abstracts of free papers presented at the obstetric ...€¦ · oral presentations 1. opioids are...

InternakmaI Journal of Obsfetric Anesthesia (1998) 1, 194-214 0 1998 Harcourt Brace & Co. Ltd

Abstracts of free papers presented at the Obstetric Anaesthetists’ Association Meeting in Harrogate, UK on7-8May1997

ORAL PRESENTATIONS

1. Opioids are unlikely to provide effective and safe analgesia in labour

M. Jones,* V. Bythell,* S.G. Graham** *Department of Anaesthesia, Royal Victoria Injirmary, Newcastle-upon-Tyne, UK

**University Department of Anaesthesia, Newcastle University, Newcastle-upon-Tyne, UK

Introduction: Recent work has again implied that despite their widespread use in labour (and perceived efficacy) pethidine and morphine do not provide analgesia in labour, but rather sedation and amnesia.’ The pain of contractions may be perceived as unchanged by the opioid even when the dose administered is sufficient to produce respiratory depression between contractions.2 Austin et al3 demonstrated that an inadequate level of opioid produced no analgesia

whatever. This implies that for an opioid analgesic to be effective in labour the onset time needs to be comparable to that of the pain, while elimination should be rapid enough to produce an acceptable level of respiratory depression between the contractions.

Methods: We used computer modelling (Stanpump, freely available from the author, Steven Shafer) to pre- dict the concentrations in the effect site after administration of the currently available opioids for which kinetic data sets are available, and compared them to the time course of the contractions of labour.

Results: The times to peak effect site concentrations of the tested drugs were: sufentanil 33Os, fentanyl 227s, alfentanil 89s, remifentanil 83s. The effect site kinetics (compared to plasma concentrations of remifentanil and the time course of a contraction) are shown in the figure for remifentanil, currently the fastest opioid available in the UK.

- - - - - Plasma concentration

- Effect site concentration

~~~~~~~~~~Cardiotocograph record

200 Time (seconds)

Figure (Paper 1) The time course of the plasma and effect site concentrations of a single bolus of remifentanil, in comparison with that of uterine contractions.

194

Abstracts 195

Conclusions: It is apparent that the effect site concentrations of remifentanil are poorly matched to the time course of a contraction. These data suggest strongly that even with patient controlled analgesia, using the fastest current opioid analgesics, it is unlikely that good quality analgesia with a low incidence of respiratory depression between contractions can be provided.

REFERENCES

1. Reynolds F, Crowhurst J A. Opioids in labour - no analgesic effect. Lancet 1997; 349: 4-5.

2. Olofsson Ch, Ekblom A, Ekman-Ordeberg G, Hjelm A, Irestedt L. Lack of analgesic effect of systemically administered morphine or pethidine on labour pain. Br J Obst Gynaecoll996; 103: 968-972.

3. Austin K L, Stapleton J V, Mather L E. Relationship between blood meperidine concentrations and analgesic response. Anesthesiology 1980; 53: 460-466.

2. Combined spinal-epidural or epidural? A randomized comparison of two low dose epidural techniques

M. Dresner, J. Bamber, J. Freeman, C. Calow Obstetric Anaesthesia, Leeds General Injirmary, Leeds, UK

Introduction: Combined spinal-epidural (CSE) analgesia produces greater maternal satisfaction than traditional high-dose epidural techniques,’ but the routine dural breach remains controversial. Before accepting CSE as the superior technique, it must be compared for efficacy and complications with an equivalent low-dose epidural regimen. This abstract presents the provisional results of such a study.

Methods: After obtaining Ethics Committee approval and written consent, all women requesting epidural analgesia in labour were randomized into one of two treatment groups. In the CSE group, analgesia was ini- tiated with 2.5 mg plain bupivacaine plus 25 pg fentanyl intrathecally via a 27 gauge Whitacre needle. The EPI group received 20 ml of 0.1% bupivacaine plus fentanyl 2 @ml epidurally. Both received main- tenance infusions of this mixture at 12 ml/h, with top- ups of infusate as required.

The groups were compared for spontaneous vaginal delivery (SVD), patient satisfaction score of ‘excellent’ (the best of four options), blood patch, resite and failure rates. Failure was defined as inability to perform the randomized procedure, patient score of ‘unsatisfactory’ (the worst choice), or withdrawal from the study by the anaesthetist because the randomized technique was deemed inappropriate. Data were collected using the Wansbeck Epidural Audit System and compared using x2 and Fisher’s Exact tests on SPSS Version 6.0 for Windows, regarding P < 0.05 as significant.

Table (Paper 2) Results. Denominators vary with completeness of data for each feature*

EPI Group n = 283 CSE Group n = 289 P value

SVD 141/268* (52.6%) 150/277* (54.2%) N.S. Excellent 193/254* (75.9%) 214/265* (80.8%) N.S. Patch l/268* (0.37%) 4/277* (1.44%) N.S. Resite 4/268* (1.49%) 3/277* (1.08%) N.S. Failure 19/282* (6.74%) 4/280* (2.85%) 0.001

Results: This first 572 participants in the study were assessed. There were more primiparas in the EPI group (75.6% versus 66.0%). There were no differences between the groups in the patients’ perception of motor block.

Discussion: These preliminary results show no statistical differences between the groups, except for fewer failures in the CSE group. Even this difference is open to debate, given our definition of failure. More numbers are required to allow valid comparison of subgroups and rates of complications. However, these preliminary results suggest there are no clear grounds for regarding either techniques as inherently superior.

REFERENCE

1. Collis R E, Davies D W L, Aveling W. Randomised comparison of combined spinal-epidural and standard epidural analgesia in labour. Lancet 1995; 345: 1413-1416.

3. Does motor block influence satisfaction with epidural analgesia?

C. Calow, M. Dresner, J. Bamber, J. Freeman Obstetric Anaesthesia, Leeds General Infirmary, Leeds, UK

Introduction: Minimizing epidural motor block is a popular goal in obstetric practice. Anticipated benefits of reduced operative deliveries and decreased postnatal backache remain unsubstantiated, but increased maternal satisfaction is reported.‘+2 This study investigates whether reduced motor block is prerequisite for high satisfaction. Rather than com- paring different dosage regimens, we have examined the range of motor block associated with a single low- dose technique.

Methods: All women in our unit receive a strictly stan- dardized low-dose epidural or combined spinal- epidural (CSE) technique based on infusion of 0.1% bupivacaine with 2 pg/ml fentanyl. Comprehensive data are recorded prospectively using the Wansbeck Epidural Audit System. Patients’ perception of motor

196 International Journal of Obstetric Anesthesia

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90

80

5 70 = 8

d 60

P .- P

50

E 8 40

t a 30

20

10

0 Motor block

Figure (Paper 3) Midwife and maternal satisfaction.

block and satisfaction are assessed by multiple choice questionnaire on the first postnatal day; the midwife’s assessment is recorded on delivery. For this study, patients assigned to one of three motor block groups (mild, moderate, severe) were compared for ‘excellent’ maternal and midwife satisfaction (the best of four options). Data from the first 671 patients on our database were examined. Complete patient data were available on 605 patients, and midwife data on 564. Statistics used were x2 and x2 trend tests, regarding P c 0.05 as significant.

Results: Demography, CSE usage, and modes of delivery were similar in the three motor block groups. Differences in maternal and midwife ‘excellent’ satisfaction were not significant (see Fig).

Conclusion: Although we have not compared the motor block groups for all confounding factors, this study suggests patient and midwife satisfaction are not influenced by maternal perception of motor block. We conclude that the pursuit of greater mobility by further dose reductions will not necessarily be rewarded by superior satisfaction.

REFERENCES

1. Russell R, Reynolds E Epidural infusion of low-dose bupivacaine and opioid in labour. Anaesthesia 1996; 51: 266-213.

2. Russell R, Dundas R, Reynolds F. Long term backache after childbirth: prospective search for causative factors. BMJ 1996; 312: 1384-1388.

Motor block moderate

n Excellent - Patient view 0 Excellent - Midwife view

Motor block severe

4. A comparison of epidural bolus administration of bupivacaine 0.25% and bupivacaine 0.1% with 0.0002% fentanyl for labour analgesia James K S, McGrady E M, Quasim I, Patrick A Glasgow Royal Maternity Hospital, Rottenrow, Glasgow, UK Introduction: Adding an opioid to local anaesthetic agents given for epidural analgesia in labour can reduce bupivacaine requirements and motor blockade. The combined spinal-epidural analgesia technique has been described where effective analgesia is provided but mothers can still walk in labour,’ but complications have been described related to dural puncture.‘,* The aim of this study is to compare a ‘mobile epidural’ solution, 0.1% bupivacaine with fentanyl, omitting the intrathecal dose, with 0.25% bupivacaine for epidural analgesia in labour.

Method: Following approval from the Hospital Ethics Committee and written patient consent, 80 women requesting epidural analgesia in labour were randomly allocated for double-blind administration of the following initial bolus: group A - 15 ml 0.1% bupiva- Caine and 50 pg fentanyl, group B-15 ml 0.25% bupivacaine. Women received 10 ml top-ups of bupivacaine 0.1% with 2 kg/ml fentanyl (group A) or bupivacaine 0.25% (group B), on request.

Results: Visual analogue and verbal scores of analgesia were similar in the two groups. All women had good analgesia 30 min after the initial bolus, though

Abstracts 197

Table (Paper 4) Data presented as median and interquartile range where appropriate

Time between Satisfaction top-ups with analgesia (min) VAS (mm)

Duration 2nd stage (h)

Instrumental delivery (number)

Group A 90 (60-l 17.5) 84 (76-90) 0.78 (0.33-0.96) 2 Group B 110 (82-140) 77.5 (72-88) 1.5 (0.83-2.5) 9 P-value 0.000 1 0.04 0.0003 0.03

time between top-ups was shorter in group A. Thirty- nine of 40 women in group A and 8 of 40 in group B were assessed as able to get out of bed. Twenty-four women in group A and 2 in group B actually mobi- lized. Duration of second stage was shorter in group A and fewer women had instrumental deliveries (Table).

Discussion: We have shown that a ‘mobile epidural’ can be provided using an epidural alone, avoiding complications of dural puncture. Bupivacaine 0.1% and fentanyl provided comparable analgesia to 0.25% bupivacaine, and women were able to mobilize if they wished. Satisfaction scores were higher in group A, who had a shorter second stage and were less likely to require instrumental delivery.

REFERENCES

1. Collis R E, Baxandall M L, Srikantharajah I D, Edge G, Kadim M Y, Morgan B M. Combined spinal-epidural analgesia with the ability to walk throughout labour. Lancet 1993; 341: 767-768.

2. Harding S A, Collis R E, Morgan B M. Meningitis after combined spinal-extradural anaesthesia in obstetrics. Br J Anaesth 1994; 73: 545-547.

5. Is a fluid preload necessary with low-dose epidural analgesia in labour?

A. Slaymaker, J. Bamber, L. Hawthorne, M. Dresner Obstetric Anaesthesia, Leeds General Injirmary, Leeds, UK

Introduction: It is common practice to administer a fluid preload before instituting epidural analgesia in an attempt to prevent hypotension. Disadvantages include inhibition of uterine contractions’ and concern about pulmonary oedema in preeclampsia or cardiac disease. It is our impression that low-dose epidural analgesia is remarkably cardiostable and fluid preloading may not be necessary. In this abstract we present the provisional results of a randomized comparison of preload versus no preload on haemo- dynamics after low-dose epidural analgesia.

Method: With Ethics Committee approval and after obtaining written consent, 26 women requesting epidural analgesia in labour were recruited. They were randomly allocated into two groups, one receiving a preload of 7 ml/kg normal saline and the other no

O! 1 0 5 10 15 20

Time (min)

Figure (Paper 5) Changes in cardiac index (mean and standard deviation).


preload. All patients received a standard epidural technique consisting of 20 ml 0.1% bupivacaine plus 2 yg/ml fentanyl. Mean arterial pressure (MAP) was measured by Dinamap automated blood pressure machine. Cardiac index (CI) was measured by transthoracic bioimpedence cardiography (BOMED), a non-invasive technique previously shown to correlate well with thermo/dye dilution in pregnant subjects2 Baseline readings were taken prior to intravenous can- nulation, and for 20 min after epidural drug administration. Results were compared using appropriate parametric and non-parametric tests.

Results: Demography was similar in the two groups. No significant changes in CI or MAP were observed within or between groups at any time during the study. The results for CI are shown in the figure.

Conclusions; It is known that blood pressure can be maintained despite reductions in cardiac output. The measurement of cardiac index is, therefore, important if subtle effects are to be detected. Our results show no significant changes in haemodynamic variables during epidural analgesia with or without preload. We conclude that the described epidural regimen confers haemodynamic stability and routine preloading can be safely abandoned.

REFERENCES

Zamora J E, Rosaeg 0 P, Lindsay M P, Crossan M L. Haemodynamic consequences and uterine contractions following 0.5 or 1.0 litre crystalloid infusion before obstetric epidural analgesia. Can Anaesth 1996; 43: 347-352. Van Oppen A C, Stigter R H, Bruinse H W. Cardiac output in normal pregnancy: a critical review. Obstet Gynecol 1996; 87: 310-318.

6. Evaluation of an oscillometric wrist blood pressure monitor for use in labour

S. Sudunagunta, A. Shennan, E Plaat Queen Charlotte’s and Chelsea Hospital, London, UK Introduction: Recently accurate oscillometric wrist monitors to measure blood pressure (BP) ,have been introduced into clinical practice. They may have a number of advantages over conventionally-placed blood pressure cuffs. These include portability, com- fort, and less interference with intravenous infusions. They may also have advantages in women who are required to avoid aortocaval compression, such as those receiving regional analgesia in labour, by allow- ing the monitor to remain approximately level with the heart. In the light of recent concerns addressed by the Health and Safety Executive regarding the use of mercury sphygmomanometry, the evaluation of any

Table (Paper 6) Upper vs lower differences

Site Mean BP mmHg (SD)

Upper arm systolic 114(15)# Lower arm systolic 118 (13) Upper wrist systolic 124 (23)# Lower wrist systolic 124 (14) Upper arm diastolic 67 (13)* Lower arm diastolic 75 (10) Upper wrist diastolic 69 (16)# Lower wrist diastolic 77 (10)

# = NS; *P c 0.02

new BP measuring technology is of particular impor- tance.

We, therefore, decided to evaluate a wrist monitor in women who required BP measurement following a regional blockade in labour. The Omron Rx (Omron Healthcare, Germany) is a light-weight accurate monitor which is applied at the wrist. The device weighs only 150 g. Its use has not yet been evaluated in labour. We decided to compare BP determined in the upper and lower limbs using a standard oscillometric monitor (Space Labs model 90207) applied to the arm with the Omron device applied to the wrist.

Patients and Methods: Four paired BP measurements were made in each of 15 women in labour. All parturi- ents had their BP measured for a period of 20 min at 5 min intervals following the insertion of a regional block. Each assessment of BP was made in pairs (wrist and arm consecutively) following the regional block. The uppermost arm in the lateral position was used for the initial measurements at 5 and 10 min and the cuffs were then applied to the opposite arm and paired recordings were made at 15 and 20 min.

Conclusions: As expected lower arm BP tended to be higher than that in the uppermost arm (systolic: 118 vs 114 mmHg, diastolic 75 vs 67 mmHg, P < 0.02). However, lower and upper wrist SBP readings were similar (124 vs 124 mmHg). The use of a wrist monitor to determine BP has significant advantages in women in labour, including reducing the errors related to posture.

7. Should epidural diamorphine be withheld after caesarean section from women who suffer severe pruritus following intrathecal fentanyl?

T. Kathir, S. M. Yentis Magi11 Department of Anaesthetics, Chelsea & Westminister Hospital, London, UK

Introduction: Pruritus is a common complication of spinal opioids.‘-3 Our combined spinal epidural (CSE)

Abstracts 199

technique for caesarean section (CS) involves intrathecal fentanyl initially, and later epidural diamorphine for postoperative analgesia. However, if a patient suf- fers severe pruritus after intrathecal fentanyl, there are no data on whether she is also likely to experience itching after epidural diamorphine. The aim of this study was to assess the correlation between pruritus after intrathecal fentanyl and that after epidural diamorphine.

Methods: Thirty-seven consecutive women undergoing CS under CSE were studied. All received 2.5-2.8 ml heavy bupivacaine 0.5% with lo-25 pg fentanyl intrathecally. Patients were asked to score their pruritus using a verbal rating scale (VRS; 0 = none, 10 = severe pruritus) at end of surgery. When pain returned, they received 2.5 mg diamorphine in 10 ml saline epidurally. VRS was assessed again 24-36 h postoperatively. Spearman correlation coefficient (p) was calculated for VRS-fentanyl and VRS-diamorphine, with statistical significance taken as P = 0.05.

Results: Five women underwent emergency and 32 elective surgery. Three received 10 pg intrathecal fentanyl; two received 20 pg; and 32 received 25 pg. None received sedative or histamine-affecting drugs. There was poor correlation between VRS-fentanyl and VRS- diamorphine and this was not statistically significant (Figure).

Discussion: The incidence of pruritus after intrathecal fentanyl has been reported as 43-83%’ and that after epidural diamorphine as 33-55%*v3 although the mechanism is unclear. Taking a VRS score of > 2 to define pruritus, we found 14% and 32% of patients itched after intrathecal fentanyl and epidural diamorphine respectively. However, our results suggest those who itch after intrathecal fentanyl do not necessarily itch after epidural diamorphine, suggesting different mechanisms. Thus, there is no reason to withhold epidural diamorphine for postoperative analgesia if a patient has suffered severe itching perioperatively following intrathecal fentanyl.

REFERENCES

1. Hunt C 0, Naulty J S, Bader A M et al. Perioperative analgesia with subarachnoid fentanyl-bupivacaine for cesarean deliverv. Anesthesioloav 1989: 71: 535-540.

2. Smith i D, Klubein K-E, Wood M L B, Macrae D J, Carli F. Diamorphine analgesia after caesarean section, Anaesthesia 1991; 46: 970-973.

3. Roulson C J, Bennett J, Shaw M, Carli E Effect of extradural diamorphine on analgesia after caesarean section under subarachnoid block. Br J Anaesth 1993; 71: 810-813.

7-

6-

0 Y AA I t v 7 1 0 1 2 3 4 5 0

VRS-diamorphlne

Figure (Paper 7) PzO.16 (95% CI -0.19 to +0.47); PzO.36.

8. The wedged supine position predisposes to haemodynamic instability and unpredictable block height during onset of obstetric spinal anaesthesia

M. Stoneham, J. Eldridge, M. Popat, R. Russell Nuf$eld Department of Anaesthetics, Oxford Radcliffe Hospital, Oxford, UK

Introduction: Spinal anaesthesia for caesarean section is commonly performed with the woman sitting, following which she is placed supine with a wedge under the right hip. This technique may produce unpredictable block heights and significant hypotension due to aortocaval compression.’ In the ‘Oxford’ position described by Carrie* the woman is placed in the left lateral position with an inflated bag under the shoul- der and pillows supporting the head. This reproduces the normal thoracic concavity seen in the supine position. Thus, viewed from the side, an upward slope is produced at the mid-thoracic level, preventing the spread of hyperbaric bupivacaine above T3-4. After spinal injection, the woman is turned to an identical right lateral position to prevent unilateral block, which is maintained until just before surgery to mini- mize aorto-caval compression.

Methods: With ethical approval and written informed consent, 40 women undergoing elective caesarean section were given 15 ml.kg’ crystalloid and then randomized. In group S, spinal anaesthesia was performed with the woman sitting following which she was placed supine with wedge. In group 0, the ‘Oxford’ position was used as described above. Both groups received 12.5 mg hyperbaric bupivacaine with 12.5 pg fentanyl. The block height, assessed by pinprick, and haemodynamic data were recorded at


350 5 10 15 20 25 30 35 40 min

Figure (Paper 8) Fall in systolic BP following spinal anaesthesia (mean + SD).

baseline and every 5 min thereafter until delivery. Ephedrine 6 mg was administered intravenously whenever blood pressure fell 20% below baseline. Times from spinal injection to incision and delivery were recorded.

Results: In group S, 7/20 women had a block to T4 at 5 min compared with O/20 in group 0 (x2 test, P = 0.0125). Block height was more variable in group S compared with Group 0 Cftest, P = 0.003). Group S women required more ephedrine (16.8 + 12.9 versus 7.5 + 7.Omg, t test, P = 0.007). Blood pressure fell faster and by a greater amount in group S (Figure). Times to incision were faster in group S women (28 f 5 versus 34 5 8 min, t test, P = 0.01). There were no significant differences in neonatal outcome between groups assessed by Apgar scores and umbilical cord blood gases.

Discussion: We have shown that spinal anaesthesia for caesarean section is more predictable and haemodynamically stable if the wedged supine position is avoided until just before incision. This may be due to the effect of gravity on the spread of hyperbaric bupivacaine with different positioning techniques and partial aorto-caval compression, which is not completely abolished by the wedged supine position.’

REFERENCES

1. Kinsella S M, Whitwam J G, Spencer J A D. Reducing aortocaval compression: how much tilt is enough? BMJ 1992; 305: 539-540.

2. Westbrook J L, Carrie L E. Combined spinaYepidura1 anaesthesia for caesarean section. Anaesthesia 1993; 48: 172-173.

9. Spinal anaesthesia for caesarean section: good for mother and baby? J. Noden, G. R. Lyons St James University Hospital, Leeds, UK Introduction: Neonatal acidosis is regarded as an indi- cation for emergency caesarean section. The aim of this prospective observational study was to assess neonatal acidosis occurring during elective spinal anaesthesia for CS.

Method: Our hospital ethics committee does not wish to consider observational studies. One hundred consecutive elective caesarean sections of singleton fetuses for maternal reasons other than ill health were studied. All the pregnancies were of 37+ weeks gestation in women of ASA grade 1 or 2 with no suspicion of utero-placental or fetal dysfunction. Antenatal blood pressure measurements were recorded.

Preload of 500 ml Gelofusine was infused whilst the epidural was sited. A combined spinaYepidura1 was performed as previously reported’ using l&15 mg 0.5% heavy bupivacaine and diamorphine 4-8 @kg. As this injection was given, rapid infusion of a second 500 ml of Gelofusine containing 30 mg ephedrine was started. Block height was assessed for the level of cold, blunt and pinprick and if full motor block and loss of sensation of pinprick to T5 or higher was not achieved, the patient was excluded. The following were measured: systolic, mean and diastolic pressure; heart rate; total dose of ephedrine given; block height; times of spinal, skin and uterine incisions and delivery.

At the time of delivery, the umbilical cord was immediately double clamped and samples from artery and vein were analysed within 5 min. A paediatrician or midwife assigned 1 and 5 min Apgar scores scores and umbilical cord blood gases

Abstracts 201

Results: There were 18 cases of neonatal acidosis (UApH < 7.2). Seven babies had UApH < 7.1. All the acidotic babies had 5-min Apgar scores of 9 or 10 and only one of them had a one minute score below 7. Fall in systolic blood pressure to less than 80% of baseline values occurred in 11 of the acidotic group (61%) and 27 of non-acidotic (34%). Initial statistical analysis of the results indicates that the only parameters that are predictive of neonatal pH are percentage change in systolic blood pressure and the diastolic pressure at 36 weeks gestation.

Conclusion: It is disappointing that despite prophylac- tic ephedrine 38% of women had a fall in systolic blood pressure to less than 80% of baseline. Low umbilical artery pH is associated with a fall in systolic blood pressure. However, neonatal acidosis occurred in 7% of deliveries without any nausea or vomiting, hypotension or bradycardia.

Given the satisfactory clinical outcome, the impor- tance of neonatal acidosis as measured by pH is uncertain.

This reports work in progress and further statistical analysis of clinical and demographic data is being performed to try and identify any factors that might predispose to neonatal acidosis.

REFERENCES

1. Lyons G, MacDonald R, Mikl B. Combined epidural/spinal anaesthesia for caesarean section. Anaesthesia 1992; 47: 199-201.

10. Spinal vs epidural anaesthesia for caesarean section in pregnancy-induced hypertension

E. G. Watson, V. A. Clark, G. Sharwood-Smith Department of Anaesthesia, Simpson Memorial Maternity Pavilion, Lauriston Place, Edinburgh, UK

Introduction: Pregnancy-induced hypertension affects 5-8% of pregnancies. It appears to involve an abnor- mal microvascular pathology, leading to an increase in vessel permeability and the development of systemic vasoconstriction. The use of epidural analgesia in this group of patients has become popular in recent years, but spinal anaesthesia, with its theoretical risk of pro- ducing rapid hypotension, was not undertaken in these patients. As no prospective study has compared the two techniques, this study was undertaken to assess their effects, particularly with regard to cardio- vascular stability, maternal and neonatal morbidity.

Methods: The study was approved by the local ethics committee. Twenty-eight women with pregnancy- induced hypertension severe enough to warrant anti-hypertensive therapy, and requiring caesarean section, consented to receive either epidural or

spinal anaesthesia by a standard technique. Baseline measurements of blood pressure were carried out in the anaesthetic room for 5 min before the instituting any regional block. All patients received 250 ml of Ringer’s solution during establishment of block; thereafter i.v. fluids were given solely to replace intraoperative blood losses. Spinal anaesthesia was achieved with 2.75 ml of 0.5% heavy bupivacaine. Epidural analgesia consisted of a test dose of 4 ml 2% lignocaine followed by 16 ml of 0.5% bupiva- Caine with 50-75 ug fentanyl. Anaesthesia was deemed adequate on achievement of a sensory block to T5; sometimes this necessitated the administration of supplementary bupivacaine in the epidural group. Blood pressure was measured and hypotension defined as a fall in systolic of 30% or more from baseline values. This was treated with incremental ephedrine. Any episode of bradycardia, nausea/ vomiting or light-headedness was also noted. Neonatal outcomes were obtained from paediatric notes and a questionnaire to ascertain maternal well-being was sent approximately one month postpartum.

Results: Twenty-eight women were initially included in the study. Six were excluded due to protocol viola- tions. Twelve women had spinals and 10 had epidurals. Half the women in each group received no ephedrine during their section. There were no differences in ephedrine requirement between the groups. Mean ephedrine usage was 6.25 mg (range O-24 mg) in the spinal group and 6.3 mg (range O-27 mg) in the epidural group. Neonatal outcomes were similar in the two groups. The incidence of maternal nausea was similar in the two groups, but analgesia was much better in the spinal group. No patient in this group complained of intraoperative pain. However, four patients in the epidural group required intraoperative analgesia. Because of this, it became unethi- cal to continue the study, which was originally scheduled to include 40 women.

Conclusion: Epidural anaesthesia has been advocated as the method of choice for caesarean section in women with pregnancy-induced hypertension, as hypotension is theoretically less brisk than with spinal anaesthesia. Our study shows no support for this theory as ephedrine requirements were similar following the two regional techniques. As maternal and neonatal outcomes were similar in the two groups and as spinal anaesthesia results in more rapid onset and better analgesia for caesarean section, it has become the preferred method of regional blockade for women with pregnancy-induced hypertension in our unit.


11. What height of block is needed for manual removal of placenta under spinal anaesthesia?

C. R. Broadbent, R. Russell John Radcliffe Hospital, Oxford, UK

Introduction: For manual removal of placenta, spinal anaesthesia avoids the hazards of general anaesthesia. There are few data on what level of block is necessary for pain-free surgery. Two studies have suggested a TlO block,‘,* but in both, 10% of women experienced intraoperative pain. We aimed to study anaesthetic management of spinal anaesthesia for retained placenta and to establish what block height was necessary for pain-free surgery.

Method: Anaesthetic management was chosen by the attending anaesthetist. Volume of local anaesthetic, maternal position and fluid management were recorded. Level of block (determined by loss of cold sensation) was documented immediately before and after surgery. The force applied by the surgeon to deliver the placenta was graded by the anaesthetist. Maternal sensations of pressure and pain were noted, graded according to severity and treated if appropriate.

Results: Over a 1Zmonth period, 70 women received spinal anaesthesia for manual removal of placenta. Hyperbaric 0.5% bupivacaine was used in all cases, with volumes ranging between 1.5 and 3.0 ml. Spinals were performed in 25 sitting patients and 43 in the lateral position, Position was not documented in two cases. Block heights ranged from L2 to T2 pre-surgery, and from L2 to Tl post-surgery.

Hypotension occurred in 14 women (20%), (defined as systolic pressure > 100 mmHg or a fall of > 30% of the initial pressure). Hypotension was unrelated to block height, volume of bupivacaine, position during injection, volume of i.v. fluid given or blood loss.

Five patients (7%) felt pain (two moderate and three severe) and two (3%) felt moderate pressure during surgery. Mild pressure was felt by 23 (300/) and nothing by 42 patients (60%). No patient with a block above T7 (total 26) felt more than mild pressure. The incidence of pain, or moderate or severe pressure was unrelated to the volume of bupivacaine used or the position during injection, or the force applied during surgery,

Discussion: We examined patients who experienced pain and those who felt moderate to severe pressure as one group, as we felt these all represented a sub-optimal result. In our study no woman with a block to T7 or above experienced pain, or moderate or severe pressure. We did not observe any increase in the incidence of hypotension with the higher blocks. However, the

patient must be well resuscitated, and intravenous fluid and ephedrine should be used as appropriate.

REFERENCES

1. Brownridge I? Spinal anaesthesia revisited: an evaluation of subarachnoid block in obstetrics. Anaesth Intens Care 1984; 12: 334-342.

2. Crawford J S. Experience with spinal analgesia in a British obstetric unit. Br J Anaesth 1979; 51: 531-534.

12. Evaluation of a midwife managed risk assessment protocol for selective administration of H, receptor blockade in labour

A. C. Norton, B. Agarwal Department of Anaesthesia, Pilgrim Hospital, Sibsey Road, Boston, UK

Introduction: Prophylaxis against acid aspiration using H, receptor blockade in all labouring women is a current area of controversy.’ Although there is wide vari- ation in policy, there is little evidence whether policies that permit feeding in labour based on obstetric risk assessment are effective in ensuring that women who require operative delivery receive appropriate gastric preparation before delivery. Using risk assessment on admission, Samaan et al* reported that 33/99 mothers undergoing general anaesthesia had been classified low risk and had not received ranitidine. This study was designed to evaluate a protocol employing continuing risk assessment in labour.

Methods; The protocol for selective feeding or ranitidine administration was introduced in July 1997 after midwife training. Midwives were asked to perform risk assessment of mothers on admission to the labour ward and if one or more of a number of defined events or findings occurred during labour. Low risk women were allowed to feed from an approved list. High risk women were given six hourly ranitidine and restricted to small amounts of clear fluids. Specific standards had been previously defined to evaluate the protocol.

Results: In the study period there were 303 deliveries. Risk assessments were not completed for 11 mothers. There were 225 normal deliveries, 2 vaginal breech delivery, 1 twins, 32 instrumental deliveries, 20 emergency and 12 elective caesarean sections. Overall, the protocol had been correctly followed and applied in 273 (93.5%) of mothers. In mothers requiring caesarean section 31 of 32 (96.9%) had been preopera- tively classified as high risk and ranitidine correctly administered. In one unassessed case, the mother presented with a footling breech and fetal bradycardia requiring immediate operation.

Abstracts 203

Only 72/225 normal deliveries were classed as low risk at the time of delivery. This was largely due to use of opiates, accounting for 108/l 50 (72%) documented risk assessments in mothers who ultimately had normal deliveries. The protocol for ranitidine administration was correctly followed in 96.8% of caesarean sections, 90.6% of instrumental deliveries and 89.6% of vaginal deliveries.

Discussion: We feel that the results support continued evaluation of this policy as we achieved a high sensi- tivity in accurately classifying high-risk patients who ultimately required intervention, at the cost of low specificity - many normal deliveries had been classified high risk. In view of the effects of opiates on gastric function in pregnancy, we continue to classify mothers who receive opiates as high risk. Reducing the use of opiates would permit more women to be regarded as low risk throughout labour.

REFERENCES

1. O’Sullivan G, May A E. Controversies - thankfully the era of ranitidine for every woman in labour has passed. International Journal of Obstetric Anesthesia 1997; 6: 173-177.

2. Samaan A K, Swanson L, Jackson I J B, Madej T H, Wheatley R G. Criterion based audit of gastric preparation in obstetric patients having general anaesthesia, in a unit with a selective feeding policy. International Journal of Obstetric Anesthesia 1995; 4: 63-64.

13. A comparison of two methods of securing epidural catheters in women during labour

H. A. Swales, N. Barnes Anaesthetic Department, St Mary’s Hospital, Portsmouth, UK

Introduction: Following insertion of an epidural for analgesia during labour the catheter has to be secured in a way that maintains sterility at the site and prevents the catheter moving from its correct position within the epidural space.

The method employed in our unit was to place a sterile swab over a loop of catheter and secure this with Sleek waterproof tape. We decided to compare this method with a combination of an Opsite dressing over the catheter loop secured with Hypafix tape around the edges to determine which method had a lower incidence of catheter migration.

Method: Following Ethics Committee approval and informed patient consent, 60 women were randomly assigned to each of the two groups. The anaesthetist secured the catheter using the assigned materials then recorded the length of catheter in the epidural space and the total length of catheter in the patient’s back. Following delivery the midwife was first asked to

assess the integrity of the dressing and then to measure the length of catheter removed from the back against a scale. Other variables recorded included the time the epidural was in situ, the mother’s weight and the temperature of the delivery room.

Results: In the Sleek group 16 of the 60 dressings were not intact before removal or had required additional securing during labour. This compared with only 5 of the dressings in the Opsite/Hypafix group (x’ = 5.8; P < 0.02).

None of the catheters in the Opsite group fell out compared with three in the Sleek group, however two in each group migrated out so far that they could no longer have been in the epidural space.

In the Sleek group 77% of the catheters migrating 1 cm or more from their skin exit point (Figure) and 63% of the dressings failing to adhere adequately did so in rooms that were deemed hot. There was no relationship between room temperature and catheter migration or dressing status in the Opsite/Hypafix group.

Conclusion: We demonstrated that the HypafixlOpsite combination is a superior epidural dressing - there is a lower incidence of catheter migration and fall out and it adheres better, especially in the hot environment found on labour wards, thus providing improved sterility at the site. In addition it permits viewing of the catheter to check that the correct position is being maintained and appears to be less irritant to the skin.

P 20 2

10

0 no movement 2cm or greater fell out

1 cm or greater out of space Catheter movement

m Sleek Opsite

Figure (Paper 13) Epidural catheter migration

204 International Journal qf Obstetric Anesthesia

14. Epidural loading-doses for primiparous women in labour - a double-blind randomized comparison of 0.2% ropivacaine, 0.1% ropivacaine with 0.0002% fentanyl and 0.1% bupivacaine with 0.0002% fentanyl

J. Eldridge, R. Russell Nuffield Department of Anaesthetics, John Radcliffe Hospital, Oxford, UK

Introduction: Low-dose epidural local anaesthetic- opioid mixtures are used for analgesia in labour while maintaining mobility.’ This study compared analgesia and clinical motor block produced by 10 ml of 0.2% ropivacaine (Group-R), 15 ml of 0.1% ropivacaine with 0.0002% fentanyl (Group-RF) and 15 ml of 0.1% bupivacaine with 0.0002% fentanyl (Group-BF).

Methods: Sixty primiparous women in the first stage of labour were recruited. An epidural was inserted at L2/3 or L3/4. Women were randomized to receive one of the above loading-dose regimens, given in a double-blind manner as two equal aliquots separated by 5 min. Every 5 min women were asked to rate the pain of the preceding contraction using a verbal numerical score (VNS). After 20 min Bromage and Medical Research Council (MRC) motor scores were recorded and sensory levels to cold assessed. If the VNS was not zero after 20 min, a supplement of 5 ml of study drug was given. The time to request a top-up was noted.

Results: The groups were comparable in age, weight, height, gestation, cervical dilation at insertion of epidural and use of oxytoxic drugs. A supplement was required after 20 min in 13/20 patients in all groups. There was no significant differences in VNS at any point (Figure), nor in time to request a top-up (Group-RF 90 f 36 min, Group-BF 79 + 29 min, Group-R 79 + 25 min). MRC motor scores were normal in 82% of mothers in Group-RF, in 80% of

Group-BE and 72% of Group-R (not significant). All mothers had normal Bromage scores.

Discussion: A differential effect on sensory and motor modalities has been proposed for ropivacaine, although ropivacaine may simply be less potent than bupivacaine.’ Using low doses of these agents should make either differential motor block or different potencies more apparent.* This study demonstrated that 20 mg ropivacaine, 15 mg ropivacaine with 30 pg of fentanyl and 15 mg bupivacaine with 30 yg fentanyl produce equivalent analgesia and motor block.

REFERENCES

1. Norman B, Jenkins G. The effect on obstetric outcome of introducing low-dose epidurals for obstetric analgesia. International Journal of Obstetric Anesthesia 1997; 6: 211-212.

2. Reynolds E Does the right hand know what the left hand is doing? International Journal of Obstetric Anesthesia 1997; 6: 257-269.

POSTER PRESENTATIONS

1. Obstetric anaesthesia in Asian and non-Asian women matched demographically

J. Morgh-Siddall, V. E. Bythell Department of Anaesthesia, Royal Victoria Infirmary, Newcastle-upon-Tyne, UK

Introduction: It has previously been shown that Asian women may be more likely to have general anaesthesia for obstetric procedures than Caucasian women.’ This may contribute to the apparent increased risk of maternal mortality in this group of women, as high- lighted in the 1991-1993 report of the Confidential Enquiry into Maternal Deaths.2 We have audited retro- spectively the relative incidence of regional anaesthesia for caesarean section in Asian women in our unit compared with that in matched Caucasian controls.

10 1 - + - Group-RF

- *. -Group-R

-C-Group-BF

2- .'-,a..-...... ,..........,.......-...

0 I I I I I I I I 0

1 5 10 15 20 25 30 35 Time (min)

Figure (Paper 14) Verbal numerical pain scores.

Abstracts 205

Table (Poster 1) Number n (%) of patients in each group. Differences between the two groups are significant P < 0.05 (see text).

Group Asian women Controls

n General Regional

Total

46 19 (41) 21(59)

Elective

13 4(31) 9 (70)

Emergency

33 15 (45.5) 18 (55)

Total

46 10 (22) 36 (78)

Elective

12 1 63)

11 (92)

Emergency

34 9 (26.5)

25 (74)

Methods: Asian women delivered by caesarean section (CS) during one year (August 1996-July 1997) were identified by manual search of the unit anaesthetic logbook and cross-checking probable names with self- reported ethnic origin collected on all hospital admissions. Forty-six Asian women were identified as having undergone CS out of a total of 832 CS (both elective and emergency). Forty-six non-Asian women were identified by finding the next person with the same postcode to undergo CS from the logbook. The records of both the Asian subjects and the postcode- matched controls were retrieved.

Data from the two groups was compared statistically using x2 test with Yates’ correction, P < 0.05 was considered significant.

Results: Results are summarized in the Table. It is clear that in both elective and emergency CS

there is a large difference in regional anaesthesia rates, and that this is particularly striking in the elective group.

Eighty percent of women came from one postal area (NE4). There is no difference between the regional rate for all LSCS in our unit for that year (78.5%) and the total rate for group B (78%).

Discussion: We have confirmed that the effect observed by Hughes et al in Leeds (UK)’ occurs in our unit, and in fact there is an even bigger difference here. This may be related to the relatively small number of Asian women presenting to our unit (5.5% of LSCS in the study period). We plan changes to attempt to increase the uptake of regional anaesthesia in this sub- group of women followed by further audit.

Table (Poster 2)

REFERENCES 1. Hughes P, Dresner M, Prasad R P Obstetric anaesthesia for

Asian patients (Abstract). International Journal of Obstetric Anesthesia 1997; 6: 207.

2. Department of Health and others. Report on Confidential Enquiries into Maternal Deaths in the United Kingdom 1991-1993. London, HMSO 1996.

2. A retrospective survey of obstetric admissions to the intensive care unit

M. P. Margarson, D. Dob, S. M. Yentis Chelsea and Westminster Hospital, 369 Fulham Road, London, UK

Introduction: Published series of obstetric patients admitted to intensive care units report mortality rates of between 0 and 20%.’ We describe our experiences over the first 56 months since the opening of a new university hospital incorporating an obstetric unit with a high-risk service.

Methods: Data on patients admitted to the Intensive Care Unit (ICU) were collected from an ICU database. We identified a further group of patients who were not admitted to ICU, but who required invasive monitoring or significant anaesthetic input, from diaries kept on the labour ward. We also identified patients in both groups who received 10 or more units of blood, or blood products, on any one day by reviewing written records from the blood transfusion laboratory (Table). These were considered massive haemorrhage.

Results: A total of 41 patients with pregnancies >20/40 were admitted.

Parameter ICU patients (n = 41) Reported ranges’

Age (mean and range) 31 (23341) year 24-3 1 year APACHE II (median and range) 8 (l-26) 614.7 Admission rate to ICU 0.31% O.lXi.68% Preeclampsia 16/41 (39%) 22-66% Eclampsia 3/41 (7%) 7733% Haemorrhage 15/41 (37%) 5-33% DIC 5141 (12%) 1 o-22% Stay (median and range) 2.3 (0.5-27) days 2-8 days Mortality 2141 (5%) O-20%


Two deaths occurred. One in a 26/40 mother with cystic fibrosis who was admitted in respiratory failure and then developed sepsis and multi-system organ failure, and one in a 26/40 mother with Eisenmengers syndrome who was transferred to another unit post-partum and died 10 days later. Both babies survived. Five patients with massive haemorrhage were managed without admission to the ICU.

Conclusions: The demographics and reasons for admission to the ICU in this series are similar to other published reports. Of note is the overall low mortality and short stay. Statistical analyses and comparisons of series with such small numbers are very difficult, and compounded by the lack of data which allow adjust- ment for case mix and severity of disease.

REFERENCE 1. Lapinsky S E, Kruczynski K, Seaward G, Farine D, Grossman

R F. Critical care management of the obstetric patient. Can J Anaesth 1991; 44: 325-329.

3. A survey of midwife, obstetric and maternal attitudes to epidurals for pain relief in labour D. N. Lucas, S. V. Millett, S. M. Yentis, A. I? Rubin, I? N. Robinson Magi11 Department of Anaesthetics, Chelsea and Westminster Hospital and Department of Anaesthesia, Northwick Park Hospital, UK

Introduction: Epidural analgesia is not the choice of all mothers. We have previously demonstrated differences in the attitudes towards epidurals of those mothers who opt for epidural analgesia and those who do not,’ and our data supported the suggestion that mothers are ‘worrying about the wrong complications’.* Obstetricians and midwives are important information sources for women and may significantly influence their choice of analgesia. The aim of this study was to investigate the relationship between

Table (Poster 3) Comparison of median values of VAS between groups

obstetric, midwife and maternal attitudes to epidural analgesia.

Methods: The survey was performed at the above two hospitals. Midwives and obstetricians were asked to complete the same questionnaire as that previously used.’ Individual perceptions regarding epidural analgesia were assessed by a ten point visual analogue scale (VAS). Maternal data from our previous study were used for comparison.

Results: VAS scores were compared using the Kruskal Wallis test. After application of the Bonferroni correction, P < 0.05 was considered significant.

Conclusion: Women who decline epidural analgesia are more worried than the other groups about the thought of a needle in their back, being paralysed and the effect on the baby. Midwives share this group’s concerns about backache and epidurals detracting from the natural childbirth experience.

All groups believe that epidurals are painful to put in, but agree that they do work. There was a relatively high level of concern amongst all groups about the possibility of epidurals contributing to the need for forceps, whereas losing control in labour was only a moderate concern. Midwives and obstetricians are more worried than patients about the possibilities of headache and difficulty in passing urine (Table).

It would seem that obstetricians are becoming more informed about epidurals but there is still a significant lack of awareness among midwives. While information sources such as midwives remain misinformed, women will continue to worry about the wrong complications.*

REFERENCES

1. D N Lucas, S V Millett, S M Yentis, A P Rubin, P N Robinson. An investigation into maternal attitudes to epidurals for pain relief in labour. International Journal of Obstetric Anesthesia 1997; 6: 209-210.

Statements to which subjects responded OBS MID W. n ipp173

w n rg;

P n= 17 n=64

The thought of a needle in my back 1 Getting a headache afterwards 3 Being permanently paralysed 0 Getting backache afterwards 2.5 Not being able to push properly and needing forceps 4 Might affect the baby 1 Takes away from a natural childbirth experience 3 Might not work properly 2.5 Painful to put in 3 Makes it difficult to pass urine 3.5 Worried that having an epidural may mean 2 losing control in labour

3 3.2

3 1 :

i :

: 02 33 3 1.5

33 0.5 0

6.5 2 6.5

0.0001 0.0001 0.0001 0.0001 NS 0.0003 0.0001 NS NS 0.0001 NS

OBS - Obstetricians; MID - Midwives; Wepi -Women who chose epidural analgesia; Wnocpi - Women who declined epidural analgesia.

Abstracts 207

2. Reynolds F. Worrying about the wrong complications. OAA Annual Meeting (Abstract) 1995.

4. Establishing epidural analgesia for labour: a comparison of intermittent bolus and continuous infusion of local anaesthetic - preliminary analysis D. McAtamney,* C. O’Hare,? U. Carabinet *Department of Anaesthetics, Queen’s University Belfast, fDepartment of Clinical Anaesthesia, Royal Group of Hospitals Trust, Belfast

Introduction: Epidural analgesia for labour is usually established by injecting intermittent bolus doses of local anaesthetic. However, up to 30% of patients may experience insufficient analgesia when this technique of drug administration is used.’ In vitro, the flow characteristics of fluid from multi-orifice epidural catheters have been shown to vary with the rate and pressure of administration.2 The distribution of local anaesthetic in the epidural space, and the resulting block, may therefore depend on whether the drug is administered by bolus injection or slow infusion. The aim of this study was to compare the sensory block and onset of analgesia after the epidural administration of 12 ml bupivacaine 0.25%, given either by intermittent bolus or continuous infusion.

Methods: Following ethics committee approval and written informed consent ASA 1 or 2 patients in active uncomplicated labour were studied. The epidural was sited using a standard technique and a test dose of 3 ml 0.5% bupivacaine given. After 5 min, patients were randomized to receive 12 ml 0.25% bupivacaine as follows: two 6 ml bolus doses 5 min apart in group A (n = 75) or continuous infusion at 72 ml.h-’ for 10 min in group B (n = 75). All observations on the mother were performed by one of two anaesthetists blinded to group allocation. The height of the sensory block (loss of temperature sensation to ice) and the presence of a motor and sympathetic block were assessed at intervals for 90 min after test dose administration. The pain relief obtained was assessed on a verbal scale (no relief, a little relief, a lot of relief or complete relief) as well as a 100 mm visual analogue scale. The incidence of unsatisfactory block or insufficient analgesia 40 min after the test dose was noted. An infusion of bupivacaine 0.1% + fentanyl 0.0004% was started at this time. Parametric and non-parametric tests of statistical analysis were used as appropriate. A P value less than 0.05 was taken as significant.

Results: The mean gestational age was significantly greater in group B than in group A (40.1 vs 39.7 weeks, P c 0.05). Otherwise there were no demographic or obstetric differences between groups. The incidence of

unsatisfactory block 40 min after the test dose was 14/75 (19%) in group A and 8/75 (11%) in group B (P = 0.3). The time from the test dose until the patient experienced ‘a lot of relief’ was similar in the two groups. The mean height of sensory block was significantly higher in group B than in group A at each assessment up to 40 min after the test dose.

Conclusions: These preliminary findings suggest continuous infusion is a useful alternative to bolus injection to establish epidural analgesia during labour. Since bolus administration carries a theoretical risk if intravenous or intrathecal injection occurs, epidural analgesia should be established by using continuous infusions.

REFERENCES

1. Beilin Y, Bernstein H H, Zucker-Pinchoff B. The optimal distance that a multiorifice epidural catheter should be threaded into the epidural space. Anesth Analg 1995; 8 1: 301-304.

2. Power I, Thorburn J. Differential flow from multihole extradural catheters. Anaesthesia 1988; 43: 876-878.

5. Volume preloading with pentastarch in elective caesarean section: a prospective, randomized double- blind trial G. W. G. French, J. B. White, M. Popat Department of Anaesthetics, Northampton District General Hospital, UK and The Nuffield Department of Anaesthetics, John Radcliffe Hospital, Oxford, UK

Introduction: In elective caesarean section under spinal anaesthesia, crystalloids are frequently infused as a volume preload to prevent hypotension, but have a short intravascular half-life. Theoretically, colloids are a better alternative.* This prospective, randomized, double-blind trial compares Pentastarch 10% with Hartmann’s solution for preloading.

Methods: One hundred and sixty patients undergoing elective caesarean section were studied. Patients were fasted for minimum of 4 h. After a blood glucose level was measured, the women were randomized to receive 15 ml.kg’ body weight of Pentastarch or Hartmann’s solution over 10 min, in the left lateral position. The appropriate infusion was covered with a black bag by a technician to ensure the study was blinded. Spinal anaesthesia was administered in the sitting position with a standard dose of heavy 0.5% bupivacaine, after which the women were returned to a wedged supine position. BP, pulse and SpO, were monitored every minute until clamping of the cord. Block height to light touch at delivery, uterine incision to delivery (UD) interval, Apgars at 1 and 5 min and cord pH were recorded. BP readings were taken on the left (dependent) arm. Falls of


Table (Poster 5) Data on hypotensive episodes, expressed as mean (SD) for the Hartmann’s and Pentastarch groups

Pentastarch Hartmann’s Mean difference P value (n = 80) (n = 80) (95% CI)

Episodes of hypotension (n) 0.18 (0.52) 0.73 (0.97) 0.55 (0.31 to 0.79) P < 0.0001t Duration of hypotension (min) 0.28 (0.9) 1.73 (2.63) 1.45 (0.84 to 2.06) P < 0.0001~ Ephedrine dose (mg) 1.35 (3.93) 8.35 (12.56) 7.0 (4.09 to 9.91) P < 0.0001t

(t = Two tailed z test, 158” freedom).

systolic BP below 90 mmHg or >30% below baseline values, whichever was the higher and nausea were treated with ephedrine (6 mg boluses). Results were analysed using x2, z tests and linear regression.

Results: The two groups, comparable in age, weight, ASA status, parity, gestation, blood glucose and dose of bupivacaine, showed no significant differences in UD interval, height of block, Apgar scores or cord pH. Significantly more patients in the Hartmann’s group (n = 38) required intervention than in the Pentastarch group (n = 10) (x2 = 21.7, P < 0.0001). There were also significantly more episodes of hypotension and ephedrine use in the Hartmann’s group than in the Pentastarch group (Table). Linear regression modelling showed the only significant variable was the preloading fluid (P < 0.001).

Methods: Twenty-four patients for elective caesarean section were randomized into two groups in a prospective, double-blind manner. A combined spinal epidural was performed. Group S received a subarachnoid injection of 2 ml of bupivacaine 0.5% in 8.0% dextrose combined with 0.5 ml of saline. Group F received 2 ml of heavy bupivacaine as above combined with 0.5 ml (25 ug) of fentanyl. The solutions were prepared by a second anaesthetist who took no further part in the procedure. Surgery began when the block was adequate, as assessed by ethyl chloride spray, to a level > T4.

Pain was assessed using a 10 cm visual linear analogue scale (0 = no pain, 10 = worst pain imaginable) at skin incision, peritoneal incision, delivery, uterine exteriorization, uterine replacement and skin closure.

Conclusions: Pentastarch is superior to Hartmann’s solution for preloading in elective caesarean section under spinal anaesthesia.

REFERENCE

1. Mathru M, Rao T L K, Kartha R K, Shanmugham M, Jacobs H K. Intravenous albumin administration for prevention of spinal hypotension during cesarean section. Anesth Analg 1980; 59: 655-658.

16-

14

12..

10,

" 6

6%.

4.

23s

O-

6. Comparison of spinal bupivacaine versus spinal bupivacaine plus fentanyl for uterine exteriorization during caesarean section M. Chilvers, S. Gowrie-Mohan, S. Eckersall Department of Anaesthesia, Lister Hospital, Coreys Mill Lane, Stevenage, UK

16 1

Introduction: Uterine exteriorization facilitates surgical repair during caesarean section.’ However, it may cause discomfort, nausea and vomiting during regional anaesthesia. It has previously been shown that epidural fentanyl reduces the discomfort of uterine exteriorization.2 We aimed to determine whether addition of fentanyl to spinal bupivacaine resulted in a reduction in discomfort during

14

12

10

n 6

6

4

2

0 I- ;

exteriorization. Figure (Poster 6)

GroupF

Abstracts 209

Episodes of nausea, vomiting, pruritus and hypotension were recorded. Epidural local anaesthetic was given at the discretion of the anaesthetist.

Results: There were no significant differences in height, weight or neonatal weight between the groups. Additional local anaesthetic (lignocaine 2% 10 ml) was given to one patient in Group S but to none in Group F. Hypotension (SBP < 90 mmHg) occurred in three patients in each group. One patient in Group F suffered pruritus and three patients in Group S complained of nausea. The Figure summarizes the pain felt by the two groups of women.

Conclusion: The addition of spinal fentanyl to bupiva- Caine significantly increases (P < 0.05 x2) the number of women having pain free uterine exteriorization without increasing unpleasant side-effects.

REFERENCES 1.

2.

Hershey D W, Quilligan E J. Extra-abdominal uterine exteriorization at cesarean section. Obstet Gynecol 1978; 52: 189-192. Lawton G, Gowrie-Mohan S, Macdonald R, Morgan B. Comparison of spinal bupivacaine versus spinal bupivacaine plus epidural fentanyl for uterine exteriorization during caesarean section. International Journal of Obstetric Anesthesia 1995; 4: 262-263.

7. Simulated major obstetric haemorrhage

I. Dillon, K. Pannikar, A. Whitfield, A. Holdcroft Department of Anaesthesia and Intensive Care, Hammersmith Hospital, Imperial College of Science Technology and Medicine, London, UK

Introduction: Postpartum haemorrhage is a common occurrence and has an incidence of 6%’ in vaginal deliveries. Although it rarely leads to mortality, major obstetric haemorrhage is a significant cause of maternal deaths, contributing to 12% of direct deaths as reported in the Confidential Enquiries into Maternal Deaths in the UK 1991-1993.2 A major feature of deaths from haemorrhage is substandard care and the recommendations have been for a team approach using agreed protocols. In addition, because such emergencies are infrequent, staff may become unfamiliar with hospital procedures and reg- ular ‘drills’ are advocated. Simulation methods are tools which can be used to evaluate performance, enhance training and identify deficiencies in protocols. Two simulation methods are described, one using a manikin and the other an actor. In the context of obstetrics where a mother is conscious and communication skills are required, it was considered that the second method may be a more suitable approach.

Methods: After preliminary discussion with the departments of obstetrics, midwifery, haematology and the switchboard and portering services, all staff were made aware of the proposed exercises. The major obstetric haemorrhage simulation began during normal working hours at a time when clinical services were not in demand. The first scenario was started in a labour suite using a standard manikin and had an end point of attachment of monitoring in the operating theatre. The second scenario started in the post delivery ward, the furthest distance from the operating theatre, with an actor playing the role of a distressed mother until surgical control of the bleeding had been achieved. One anaesthetist was designated to monitor the proceedings and to provide input as required. All other staff involved were part of the emergency team. A debriefing session for all anaesthetic, obstetric and haematological staff was scheduled soon after the event.

Results: The first drill identified a lack of familiarity by staff with the protocol for major obstetric haemorrhage and a lack of essential equipment. These deficiencies were rapidly corrected but the second simulation was delayed because of inadequate staffing levels, The use of a ‘live’ simulation increased the realism of the situation. The drill again identified protocol deficiencies particularly relating to the supply of group specific blood and the inclusion of operating department per- sonnel. There were also essential items of management such as patient support, which could be improved.

Conclusions: Conducting ‘drills’ for major obstetric haemorrhage is essential to test protocol design and staff training. The clinical time available in which to conduct realistic scenarios within the context of a local obstetric service is very limited. Professional and managerial support for this time has to be given within training programmes for all staff.

REFERENCES

1. El-Refaey H, O’Brien P, Morafa W, Walder J, Rodeck C. Use of oral misoprostol in the prevention of postpartum haemorrhage. Br J Obstet Gynaecoll997; 104: 336339.

2. Department of Health and others. Report on the Confidential Enquiries into Maternal Deaths in the United Kingdom 1991-1993. London, HMSO 1996.

8. Anaesthetic techniques for emergency caesarean section - a survey of consultants and specialist registrars in the Mersey region

P Barclay,* G. Thind *Liverpool Women’s Hospital, Crown Street, Liverpool, UK, Fazakerley Hospital, Lower Lane, Liverpool, UK

210 International Journal sf Obstetric Anesthesia

Table (Poster 8) Type of anaesthesia selected

Spinal Epidural GA

Severe fetal distress Consultant 3 (9%) 0 (0%) 30 (91%) SPR 16 (32%) 0 (0%) 32 (67%) P = 0.01

Placenta praevia Consultant 20 (63%) 3 (9%) 9 (28%) (low lying, posterior) SpR 15 (31%) 8 (17%) 25 (52%) P = 0.02 Failed epidural Consultant 11 (33%) 4 (12%) 18 (55%) Conversion SPR 12 (26%) 4 (9%) 3 1(66%) P = 0.58

Introduction: Regional anaesthetic techniques have become increasingly popular for elective caesarean section.’ However, enthusiasm for such techniques may lead to their use by junior anaesthetists in certain emergency situations where a general anaesthetic would be more appropriate. The aim of the survey was to determine the current balance between regional and general techniques in emergency caesarean sections and to evaluate any difference in attitude between junior and senior anaesthetists in the Mersey region.

Methods: A postal questionnaire was sent to all the consultant members of the Society of Mersey Obstetric Anaesthetists and to all specialist registrar anaesthetists in the Mersey region. Respondents were asked to indicate their opinion regarding the balance between regional and general techniques for emergency caesarean section. They were also asked to indicate which anaesthetic technique they would use for three different obstetric clinical scenarios. The x2 test with Yate’s correction was used for statistical analysis.

Results: Questionnaires were returned by 33 of 39 consultants (85% response rate) and 48 of 62 specialist registrars (77% response rate). Fifty-two percent of all respondents felt that the proportion of cases con- ducted under GA was ‘too high’, 40% felt the number was ‘about right’ and 8% ‘too low’. There was no significant difference between consultants and specialist registrars’ opinions.

The responses to the clinical scenarios are summarized in the Table.

Conclusion: Significant differences of opinion exist between consultants and junior anaesthetists The results indicate that there is pressure to use regional techniques which may account for the signif+cantly greater proportion of juniors who would use spinal anaesthesia for severe fetal distress. Conversely, consultants are more willing to use a regional technique for placenta praevia, possibly reflecting their greater experience of the low risk of significant haemorrhage in this situation. The majority of anaesthetists prefer general anaesthesia following a failed epidural, indicating the uncertainty regarding the appropriate spinal dose.

REFERENCE

1. Brown G W, Russell I E A survey of anaesthesia for caesarean section. International Journal of Obstetric Anesthesia 1995; 4: 214-218.

9. Attitudes to feeding after caesarean section: a survey of the current practice of obstetric units in the UK

L. M. Worthington, A. J. Mulcahy, R. Sashidharan, S. White The Royal London Hospital, Whitechapel, London, UK

Introduction: In recent years there have been many publications examining the benefits of early feeding following surgery. Despite this, very few obstetric units have protocols to guide the dietary management of women following caesarean section. We surveyed the working practices of 100 obstetric units in the UK; the questionnaires were completed and returned by midwives.

Methods; Identical questionnaires with stamped addressed return envelopes were sent to 100 obstetric units in the UK. The data are expressed as percentages of returned valid questionnaires.

Results: Ninety-three of the 100 questionnaires dis- patched were returned; all were valid. Only 21.5% of respondents had a departmental policy concerning feeding after caesarean section. The decision to feed was taken by the midwife in 78.5% of units, the obstetrician in 37.6% and the anaesthetist in 3.2%. The women themselves were only consulted in 14% of units. Women were routinely maintained nil by mouth in 47.3% of units following caesarean section under general anaesthesia, 17.2% of them adopted this policy if the operation was done under regional anaesthesia. Of those that were maintained nil by mouth, 15.1% were starved for longer than 6 h following general anaesthesia but only 6.5% were starved for the same period following caesarean section under regional anaesthesia. The commonest factors used to assess whether women are ready to take solids orally were the ability to retain oral fluids 87. I%, hunger 69.9%, thirst 67.7%, bowel sounds

Abstracts 211

65.6% and passing flatus in 39.8%. Nausea and vomiting were considered a contraindication to feeding by 75.3% and 82.8% of midwives respectively.

Conclusion: Historically, patients have been starved following abdominal surgery until bowel sounds have returned or flatus has been passed. There is now evidence to show that early feeding following caesarean section does not increase the incidence of gastro- intestinal symptoms,‘~* and that it can actually reduce morbidity and length of stay in hospital.) Despite this, our results show that many women continue to be starved for long periods following surgery.

A worrying 78.5% of the obstetric units surveyed did not have a protocol for feeding. The absence of guidelines resulted in a variable period of starvation which was generally dependent on the preference of the individual midwife. We suggest that there should be departmental protocols to guide midwives in the feeding of women following caesarean section, this should in turn reduce the time taken to resume a normal diet.

REFERENCES

Kramer R L, Van Someren J K, Qualls C R, Curet L B. Postoperative management of cesarean patients: the effect of immediate feeding on the incidence of ileus. Obstet Gynecol 1996; 88: 29-32. Burrows W R, Gingo A J, Rose S M, Zwick S I, Kosty D L, Dierker L J, Mann L I. Safety and efficacy of early postoperative solid food consumption after cesarean section. J Reprod Med 1995; 40: 463467. Soriano D, Dulitzki M, Keidar N, Barkai G, Mashiach S, Seidman D S. Early oral feeding after cesarean delivery. Obstet Gynaecol 1996; 87: 1006-1008.

10. Oxygen transfer to the fetus: a survey of knowledge in maternity care professionals

J. Thurlow, S. M. Kinsella Anaesthetic Departments, Southmead Hospital and St Michael’s Hospital, Bristol, UK

Introduction: We were concerned with an impression that healthcare workers were not familiar with the beneficial effects for the fetus of maternal oxygen inhalation. This is well documented, although conflicting results in the past have led to differing recommendations. We surveyed maternity care professionals to check their understanding of factors affecting fetal oxygenation which are susceptible to treatment.

Method: Seventy-four anaesthetists, midwives and obstetricians were asked questions on normal values of arterial oxyhaemoglobin saturation in non-preg-

nant and pregnant adults, oxyhaemoglobin saturation in the umbilical vein of a healthy term fetus and the effect of maternal oxygen inhalation on fetal oxygenation. They were also asked to suggest other factors which might alter fetal oxygenation during labour.

Results: Normal values for arterial oxyhaemoglobin saturation were known or guessed correctly in most cases: 70 (92%) for non-pregnant and 65 (88%) for pregnant. Nine (12%) people said that they knew the value of umbilical vein oxygen saturation’-’ but only three were correct. Fifty-three guessed a value, and 10 were right. Thirty-two (43%) thought that the value is 2 90%.

Only 35 (47%) believed that maternal oxygen administration would increase oxygenation in the fetus2A with 5 equivocal; 7 (9%) people knew the expected increase in fetal umbilical vein saturation with maternal oxygen therapy.3*4 Out of the 3 other aspects of intrauterine resuscitation in UK practice (avoidance of aortocaval compression, tocolysis, attention to maternal circulation and blood pressure), 3 (4%) identified 3, 12 (16%) identified 2, 44 (59%) identified 1 and 15 (20%) did not identify any. No one mentioned amnioinfusion, or alternative positions to relieve umbilical cord compression.

Conclusions: Oxygen level in the fetal circulation is at its highest in the umbilical vein. It reflects the ade- quacy of oxygen delivery to and transfer across the placenta. Although normal values are not readily available in textbooks, the low oxygen level compared to the adult and the potential for improvement with maternal oxygen inhalation are essential facts for maternity-care professionals2

We found a poor level of knowledge about this, as well as other therapeutic possibilities for the acutely hypoxic fetus. This suggests that intrauterine resuscitation might not be carried out effectively and enthusiastically.

REFERENCES

Soothill P W, Nicolaides K H, Rodeck C H, Campbell S. Effect of gestational age on fetal and intervillous blood gas and acid-base values in human pregnancy. Fetal Therapy 1986; 1: 168-175. Bassell G M, Marx G F. Optimization of fetal oxygenation, International Journal of Obstetric Anesthesia 1995; 4: 238-243. Ramanathan S, Gandhi S, Arismendy J, Chalon J, Tumdorf H. Oxygen transfer from mother to fetus during cesarean section under epidural anesthesia. Anesth Analg 1982; 61: 576581. McNamara H, Johnson N, Lilford R. The effect on fetal arteriolar oxygen saturation resulting from giving oxygen to the mother measured by pulse oximetry. Br J Obstet Gynaecol 1993; 100: 4464l9.


11. Blood pressure measurement in late pregnancy: effect of lateral position and instrument S. M. Kinsella, M. Pirlet Anaesthetic Department, St Michael’s Hospital, Bristol, UK

Introduction: Hydrostatic differences between arms in the lateral position mean that blood pressure (BP) measured with the cuff on the uppermost arm is significantly lower than while supine.’ We investigated the size of this effect using an automatic instrument (Dinamap) and sphygmomanometry. In addition, we noted the effect of using Korotkoff sound 5 rather than 4 to identify diastolic pressure, as recently suggested.2

Method: Eleven normotensive women in the antenatal clinic were studied in the right lateral and supine with pelvic tilt positions. Two Dinamaps were used to measure BP in each arm simultaneously. The same cuffs were used for sphygmomanometric readings. Position and instrument sequence was randomized. All readings were taken in duplicate and averaged (except for K4-K5 differences).

Results:

Mean difference K4 minus K5 was 3.3 mmHg in both maternal positions (SD 3.7; range O- 20 mmHg). Dinamap diastolic was usually closer to K4 than K5. For both instruments, dependent arm BP in lateral position was close to supine, uppermost arm significantly lower (Figure).

Conclusions: K5 is now recommended as the point of determination of diastolic pressure.2 In labouring women mean K4 was found to be 10 mmHg higher than Dinamap diastolic,’ and, therefore, we expected that K5 might be closer to Dinamap diastolic. However, K5 was usually lower and K4 almost the same as Dinamap diastolic. Hydrostatic effects in

Dinamap

the lateral position are similar, qualitatively and quantitatively, using these two methods of measuring BP: BP is lower in the upper arm but similar in the dependent arm when compared with the supine position.

REFERENCES

1. Kinsella S M, Spencer J A D. Blood pressure measurement in the lateral position. Br J Obstet Gynaecol 1989; 96: 1110-1112.

2. de Swiet M, Sherman A. Blood pressure measurement in pregnancy. Br J Obstet Gynaecoll996; 103: 862-863.

3. Hasan M A, Thomas T A, Prys-Roberts C. Comparison of automatic oscillometric arterial pressure measurement with conventional auscultatory measurement in the labour ward. Br J Anaesth 1993; 70: 141-144.

12. Damage to epidural catheters by withdrawing through the Tuohy needle

I. de Beaux, A. S. Buchan Department of Anaesthesia, Simpson Memorial Maternity Pavilion, Edinburgh, UK

Introduction: Damage to epidural catheters with shearing and retention of part of the catheter within the patient is a recognized complication of epidural anaesthesia, and may occur during insertion if the catheter is withdrawn through the Tuohy needle. It is thus widely recommended that the epidural catheter should never be withdrawn through the Tuohy needle.‘s2 A survey of anaesthetists was undertaken to document the practice of epidural catheter insertion and any observed complications of withdrawing the catheter through the Tuohy needle.

Methods: A confidential questionnaire was sent to 193 anaesthetists working in the south east of Scotland enquiring about current practice in the use of modern disposable epidural needles.

Results: The study group comprised 127 (91%) of the 140 anaesthetists responding (response rate 73%) who

Sphygmomanometer

mm@2 60’ 11 60, x

!? 1 I

40’

x _ mmHg ,i 1 1 i 1

SUP SUP R Lat R Lat SUP SUP R Lat R Lat Right Left Right Left Right Left Right Left arm arm arm arm arm arm arm arm

Figure (Poster 11)

Abstracts 213

routinely sited epidurals. Sixty-seven responders were consultants, seven in non-training grades and 53 in training grades (18 senior registrars, 18 registrars and 17 senior house officers). Thirty-five responders (28%) checked that the epidural catheter passed through the Tuohy needle before insertion into the patient. Of these 26 (74%) pulled the catheter back through the needle, potentially exposing the catheter to damage. On direct questioning 40% (50 out of 125 completed replies) reported that they would never withdraw the epidural catheter through the Tuohy needle. However, when asked what they would do if there was any difficulty in threading the catheter into the epidural space, only 39 (31%) reported that they removed the needle and catheter together as recommended. The remaining 86 responders (69%) all pulled the catheter back out through the needle before performing a manoeuvre, such as rotating the needle and injecting saline or local anaesthetic, to aid threading of the catheter. This group included 49 consultants, three non-training grades, 15 senior registrars, 13 registrars and six senior house officers. Only four responders (3%), all of whom were consultants, had witnessed a single case each of catheter damage by withdrawal through the Tuohy needle.

Conclusion: Sixty-nine percent of anaesthetists routinely siting epidurals withdrew the epidural catheter through the Tuohy needle during insertion contra- vening current teaching and the manufacturers’ instructions. Damage to epidural catheters, with shearing and retention of part of the catheter within the patient, appears to be a very rare event.

REFERENCES

1. Bonica J J, McDonald J S. Epidural Analgesia and Anesthesia. In: Bonica J J, McDonald J S, eds. Principles and Practice of Obstetric Anesthesia and Analgesia, 2nd edn. Malvern: Williams and Wilkins, 1995; 439.

2. Portex Ltd. Hythe UK. Epidural Minipack Systems Instructions for Use. 1996.

13. The effect of gender, facial hair and mask wiggling on bacterial fallout H. A. McLure,T M. M. Mannan?, C. A. Talboys,$ B. S. Azadian,$ S. M. Yentist fkfagill Department of Anaesthetics and JDepartment of Medical Microbiology, Chelsea & Westminster Hospital, London, UK

Introduction: The use of surgical masks for regional anaesthesia remains controversial. There are few clinical data and laboratory evidence is conflicting. Masks prevent bacterial dispersal in front of and below the mask during talking.‘,2 However, mask

0=0.01

10 1 ‘pdl.oo1

BM CSM F

Figure (Paper 13)

wiggling may increase bacterial fallout.3 We postu- lated that differing results may be due to differing amounts of facial hair, so reproduced Schweizer’s laboratory model to compare bacterial fallout below female, bearded and clean shaven male subjects with and without mask wiggling.

Method: Thirty volunteers (10 females [F], 10 clean shaven males [CSM], 10 bearded males [BM]) wore a soft pleated mask for two 90s periods: (i) the subject remained still; (ii) the subject wiggled the mask against the face. Blood agar plates were placed 6 inches below the subjects’ lips and were changed between periods. All plates were incubated at 37°C for 24 h then the number of bacterial colonies per plate counted by a microbiolo- gist blinded to the plate sequence. Results between groups were analysed using the Kruskal-Wallis test, and within groups using one-sided Wilcoxon signed rank test (P c 0.05 taken as significant).

Results: As shown, before mask wiggling the differences between the groups BM and CSM, and between BM and F, were significant. Wiggling the face mask produced a significant difference in bacterial fallout in BM (P = 0.03) and F (P = 0.03), but not for CSM (P = 0.35).

The bacterial types isolated were coagulase nega- tive Staphylococcus (50 colonies), non-haemolytic Streptococci (8 colonies) and others (2 colonies).

Conclusion: Females and bearded males may increase bacterial contamination of the sterile field by wiggling the face mask. To reduce this risk, females should avoid wiggling, and bearded males should avoid wiggling the mask or should remove their beard. However, clean shaven men may wiggle their mask with impunity. It should be noted that bacterial


fallout induced by mask dermabrasion appears less than the bacterial dispersal from a speaking subject when face masks are not worn,“2 supporting the routine wearing of face masks when performing regional anaesthesia.

REFERENCES

Phillips B, Fergusson S, Armstrong P, Anderson F, Wildsmith J. Surgical face masks are effective in reducing bacterial contamination caused by dispersal from the upper airway. B J Anaesth 1992; 69: 407-408. McLure H A, Talboys C A, Azadian B S, Yentis S M. Surgical face masks and downward dispersal of bacteria. Anaesthesia (in press). Schweizer R. Mask wiggling as a potential cause of wound contamination. Lancet 1976; 2: 1129-l 130.

14. Women with pre-existing backache: a prospective follow-up one year after delivery

D. N. Lucas, M. R. Nel, S. M. Yentis Magi11 Department of Anaesthetics, Chelsea & Westminster Hospital, London, UK

Introduction: A common perception persists among the obstetric population that an epidural in labour might subsequently result in the development of backache, despite evidence to the contrary.’ This fear tends to be exacerbated in women with pre-existing backache although it has been demonstrated that epidural analgesia is an effective technique in this group.* We report a prospective follow-up of such women to assess their backache during the year following delivery, and elucidate any possible effect of regional analgesia.

Methods: We recruited women with pre-existing backache referred to the Obstetric Anaesthesia Assessment Clinic for advice with regard to analgesia in labour. The history of the back problem was recorded and they were asked to score the severity of backache in

the 12 months preceding conception, using a verbal rating scale. Subsequent provision of analgesia in labour was routine, and details of the mode used were recorded. A telephone questionnaire one year after delivery assessed the current status of their backache.

Results; Of 58 women initially recruited, three were excluded from follow-up because of miscarriages or neonatal deaths. Of the remainder, 38 were success- fully followed up (69%). The back problems were divided into three groups, as shown in the Table. The data was analysed using Fisher’s Exact Test.

Conclusions: The overall epidural rate amongst all women recruited was 74.5%. This figure is high in comparison with the rates for primiparas (58%) or multiparas (35%) in our unit, but compares with the 71% quoted in a previously published small series.g This high rate may reflect exacerbation of pre-existing backache during the course of labour.

The numbers followed up are currently too small to permit analysis of epidural and non-epidural groups. However, the results to date demonstrate a statistical significance (P c 0.05) between non-specific backache, which had an 83% likelihood of being better or the same at one year follow-up, and backache associated with disc lesions, for which the corresponding figure was 45%. This study is continuing.

REFERENCES

1. Breen TW, Ransil BJ, Groves PA, Oriol NE. Factors associated with back pain after childbirth. Anesthesiology 1994; 81: 29-34.

2. Roseag OP, Yarnell RW. The obstetrical anaesthesia assessment clinic: a review of six years experience. Can J Anaesth. 1993; 40: 346-356

3. Dresner M, Freeman J, Cole P. Obstetric anaesthesia for patients with chronic back problems. Br J Anaesth 1997; 78: A.349.

Table (Poster 14) Follow-up of women at one year

Scoliosis Disc problems Non-specific backache WB S WB S WB S

Epidural 1 0 0 5 4 1 4 10 4 No epidural 1 1 1 1 0 0 0 3 2

W- backache worse at one year; B - backache better at one year; S - backache unchanged at one year.

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