This house believes that point of care coagulation testing devices should be mandatory on labour ward

The argument against

Jim BamberCambridge University Hospitals

• For what purpose would I want POC coagulation testing on the labour ward?

• What POC coagulation testing devices are available?• What are the implications of having POC coagulation 

testing on the labour ward?• What is the cost of POC coagulation testing?• What is the evidence that POC coagulation testing 

would benefit my patients?• Could POC coagulation testing on the labour ward be 

harmful?

Disclosure

On one hand…• I have no expertise in POC 

coagulation testing• I have not undertaken any 

research in POC coagulation testing

• I am not a haematologist• I am not even related to a 

haematologist• I have never used TEG/ROTEM

On the other hand…• I work in a large tertiary care 

maternity hospital• I have an interest in obstetric 

haemorrhage• I have written guidelines on 

obstetric haemorrhage• I have been chair of my HTC and 

RTC• Our obstetric haematologist

thinks we should have a TEG/ROTEM on our labour ward

• I would like to have a TEG/ROTEM

Why would we want POC coagulation devices on the labour ward

• Assessing warfarin therapy in parturients• Assessing heparin therapy in parturients• Haematological screening and investigations• Regional analgesia/anaesthesia in thrombocytopenic parturients

• Management of obstetric haemorrhage

Why would we want POC coagulation devices on the labour ward

• Assessing warfarin therapy in parturients• Assessing heparin therapy in parturients• Haematological screening and investigations• Regional analgesia/anaesthesia in thrombocytopenic parturients

• Management of obstetric haemorrhage

…..and we don’t have time to wait for the lab result

Why would we want POC coagulation devices on the labour ward

• Assessing warfarin therapy in parturients• Assessing heparin therapy in parturients• Haematological screening and investigations• Regional analgesia/anaesthesia in thrombocytopenic parturients

• Management of obstetric haemorrhage

…..and we don’t have time to wait for the lab result

THE DEVICES AVAILABLE

What is available?

Prothrombin Time [PT] International Normalized Ratio [INR] Activated Partial Thromboplastin Time [aPTT]Activated Clotting Time [ACT] Platelet function testing

What is available?

Thromboelastography (TEG)  Thromboelastometry (ROTEM)

The Platelet Function Analyser

Used to screen for platelet function abnormalities  e.g. vWD, congenital platelet defects, aspirin therapy. Has a high negative predictive value.Should only be used on normal platelet count samples and on normal haematocrit samples

Low Platelets and Regional BlocksA count of > 75 x 10-9.l-1 has been proposed as an adequate level forregional blocks when there are no risk factors and the count is notdecreasing. In pre-eclampsia, a decreasing platelet count isaccompanied by other coagulation abnormalities, and this is assumed tobe the case once the platelet count decreases to below 100 x 10-9.l-1. Ifthe platelet count is below this value, a coagulation screen should beperformed – if this is normal, it would be reasonable to perform aregional block down to a level of 75 x 10-9.l-1, depending on the rate ofdecrease in platelet count. In idiopathic thrombocytopenic purpura andgestational thrombocytopenia, there are reduced platelet numbers, butnormal function. In these situations, expert opinion is that anexperienced anaesthetist might reasonably perform a neuraxialblockade providing the platelet count is > 50 x 10-9.l-1 and stable, butan individual risk–benefit assessment should be made

Association of Anaesthetists of Great Britain and Ireland, Obstetric Anaesthetists’Association and Regional Anaesthesia UK. Regional anaesthesia and patientswith abnormalities of coagulation. Anaesthesia 2013; 68: pages 966‐72

A Labour Ward Point of Care Platelet Counter

Why would we want POC coagulation devices on the labour ward

• Assessing warfarin therapy in parturients• Assessing heparin therapy in parturients• Haematological screening and investigations• Regional analgesia/anaesthesia in thrombocytopenic parturients

• Management of obstetric haemorrhage

…..and we don’t have time to wait for the lab result

Conclusion: Fibrinogen level was the parameter that best correlated with increasing volume of haemorrhage and was the most useful marker of developing haemostaticimpairment.

This house believes that point of carefibrinogen measurement  devices should be mandatory on 

labour ward

This house believes that point of care viscoelastic devices should be mandatory on labour ward

Viscoelastic Devices

TEG (A)                                           ROTEM (B)

Tynngard et al. Thrombosis Journal (2015) 13:8

What does it all mean?

Viscoelastic assessment of fibrinogen 

• The contribution of fibrinogen on clot firmness is measured by using platelet inhibitors

• TEG uses abciximab (Functional Fibrinogen)• ROTEM uses cytochalasin D (FIBTEM)• Both derive fibrinogen concentration from maximum trace amplitude (MA for TEG and MCF for ROTEM)

• Time taken to achieve MCF/MA 20‐40 mins

HOW ACCURATE IS THE VISCOELASTIC ASSESSMENT OF FIBRINOGEN?

Anesthesia & Analgesia, 2014 118(5), 933–935. 

DISCUSSIONOverall in this study, the fibrinogen level was on average overestimated by 1.0 g/L using TEG® functional fibrinogen compared with the fibrinogen plasma concentration, with similar findings in patients and healthy blood donors. It is important to note that 86% of the fibrinogen levels below 2 g/Lwere missed when analyses were done using functional

fibrinogen instead of conventional methods.

Huissoud et al (2009). Bedside assessment of fibrinogen level in postpartum haemorrhage by thrombelastometry. BJOG : 116(8), 1097–1102

“Give fibrinogen 3G if FIBTEM A5

TEG AND ROTEM ARE NOT INTERCHANGEABLE

TRAINING AND QUALITY ASSURANCE

Training and Quality Assurance

• Staff need training: standardisation of technique and interpretation

• Internal quality assurance: daily calibration• External quality assurance• Laboratory support: for assurance standards, troubleshooting, consumable supply, servicing

• Connectivity with patient record systems 

Karon (2014). Clinica ChimicaActa, 436(C), 143–148. 

The precision of the tests varied greatly for both devices, with coefficients of variances ranging from 7.1 to 39.9% for TEG and 7.0 to 83.6% for ROTEM. Some centers returned results that were sufficiently different from those obtained by other participants to predict alterations in patient management decisions. Our data indicate that regular EQA/proficiency testing is needed for these devices.

Seminars in Thrombosis and Hemostasis, 2010 36(07), 757–763. 

United Kingdom National External Quality Assessment Service

Discussion

Thissystematicinvestigationrevealslargedifferencesintheresultsofsomethromboelastometryparametersanalysesandlackofhomogeneity.Differencesappearnotonlybetweenanalysers,butalsobetweenthedifferentchannelsofthesameanalyser,betweenmorningandafternoonmeasurementsandwhenfourweeksapartmeasured.Furthermore,thereisaninconsistencywithinindividualtests(INTEM,EXTEM,FIBTEM,APTEM,HEPTEM).

Thromb Haemost 2014; 111: 1161‐1166

As with all POC devices, there is a concern that the devices are not adequately maintained, supervised, and that quality controls are not done on a regular basis. Furthermore, nonlaboratory personnel are running these POC tests, which may lead to further errors if they are not adequately trained (TEG and Sonoclot have been listed as moderate complexity tests by the Clinical Lab‐ oratory Improvement Amendment).

Alternatively, to minimize these problems and release the operating room/intensive care unit personnel, the so‐called POC coagulation analyzers have been recently moved into the central laboratory in some hospitals, thereby no longer being located at the bedside. A trained person runs the viscoelastic coagulation test and the results (evolving signatures) are submitted real‐time to the patient’s site. 

Ganter, M. T., & Hofer, C. K. (2008) Anesthesia & Analgesia, 106(5), 1366–1375.

HOW MUCH WILL IT COST?

Jackson, G. N. B., Ashpole, K. J., & Yentis, S. M. (2009). The TEG ®vs the ROTEM ®thromboelastography/thromboelastometry systems. Anaesthesia, 64(2), 212–215. 

Cost

Benefits forgone by particular use of resourcesPalmer, S., & Raftery, J. (1999) BMJ, 318(7197), 1551

Opportunity cost

“If your labour ward was given £25,000  to reduce maternal morbidity what would be your priority spend?”

An unscientific poll of obstetric anaesthetic opinion makers (aka OAA Committee)February 2016

86% response rate 

Additional staff (midwives)Midwifery education and training 

More consultant obstetric anaesthetic on‐call sessions Maternity HDU with staffA replacement blood fridge

Maybe a ROTEM  

With thanks to Nuala Lucas Polling Services

HOW OFTEN WILL I USE IT?

How often would I use a TEG/ROTEM

Number of episodes of Major Obstetric Haemorrhage* per month in England• 25%1 of labour wards will have 1 per month2

• 35%1 of labour wards will have 2 per month• 40%1 of labour wards will have >2 per month

*Massive Obstetric Haemorrhage = Blood loss  ≥ 2500mls or blood transfusion  ≥ 5 units or treatment for coagulopathy1. Based on NHS Maternity Statistics England 2013/14 (HSCIC 2014) 2. 0.6% incidence (Scottish Confidential Audit of Severe Maternal Morbidity 2014)

WHAT IS THE EVIDENCE IT WILL BENEFIT MY PATIENTS?

Cochrane Database of Systematic Reviews 2011, Issue 3. 

Authors’ conclusions

There is an absence of evidence that TEG or ROTEM improves morbidity or mortality in patients with severe bleeding. Application of a TEG or ROTEM guided transfusion strategy seems to reduce the amount of bleeding but whether this has implications for the clinical condition of patients is still uncertain. More research is needed.

Hunt H, Stanworth S, Curry N, Woolley T, Cooper C, Ukoumunne O, Zhelev Z, Hyde C. 

Cochrane Database of Systematic Reviews 2015, Issue 2.

Authors’ conclusions

We found no evidence on the accuracy of TEG and very little evidence on the accuracy of ROTEM. The value of accuracy estimates are considerably undermined by the small number of included studies, and concerns about risk of bias relating to the index test and the reference standard. We recognise that the reference standards of PT and INR are imperfect, but in the absence of embedded clinical consensus these are judged to be the best reflection of current clinical practice. We are unable to offer advice on the use of global measures of haemostaticfunction for trauma based on the evidence on test accuracy identified in this systematic review. This evidence strongly suggests that at present these tests should only be used for research. 

The Committee considered the clinical evidence on the use ofviscoelastometric testing in managing postpartum haemorrhage. It noted that the review did not identify studies that compared clinical outcomes among women with postpartum haemorrhage who were tested with viscoelastometric devices and those who were not.

The Committee concluded that more evidence is needed on theuse of viscoelastometric devices in the management of postpartumhaemorrhage.

Have I Missed Something?A Literature Search

• A Medline search with search strategy:(thrombelastography OR viscoelastography OR TEG OR ROTEM) AND (Obstetrics OR pregnancy) limits: Humans, Clinical trials, Meta‐Analysis, Randomized Controlled Trial

• No RCT ever

• 2 clinical trials since 20141.  Mallaiah, S., Barclay, P., Harrod, I., Chevannes, C., & Bhalla, A. (2015). Introduction of an algorithm for ROTEM‐guided fibrinogen concentrate administration in major obstetric haemorrhage. Anaesthesia, 70(2), 166‐75.

2. de Lange, ,N.M., van Rheenen‐Flach, ,L.E., Lancé, ,M.D., Mooyman, L., Woiski, M., van Pampus, ,E.C., Scheepers, H. C. (2014). Peri‐partum reference ranges for ROTEM(R) thromboelastometry. British Journal of Anaesthesia, 112(5), 852‐9.

IS IT REQUIRED AS A STANDARD OF CARE?

What is mandatory on the labour ward?

Saving Lives, Improving Mothers’ Care

No mother died for want of a TEG or ROTEM device (or any other point of care coagulation device)

Mothers did die because of :

• poor communication and poor teamwork• failure to recognise bleeding, • delayed resuscitation and blood transfusion• delayed provision of coagulation factors• misinterpretation of results provided by 

haemoglobin point of care devices

IS THERE A RISK OF HARM?

Risk of Harm

• We don’t know – we haven’t done the studies• Risks of misinterpretation of data that may adversely affect patient care

• Risks of misuse of the tests or failures of quality assurance

• The ‘HemoCue Lesson’ from the CEMD  

IS THE TECHNOLOGY VERY NEW?

Where are we now?

• Viscoelastic technology developed in 1948• In 2016 still no RCT of the use of viscoelastic devices in obstetrics 

• Questions remain about: how best to interpret viscoelastic data, quality assurance and staff training and competency

• No evidence to support use of any other alternative POC coagulation technology

This house believes that the obstetric anaesthetic community must sponsor and deliver a large RCT of the benefits or harms of point of care viscoelastic devices on patient 

outcomes before another decade has passed.  

I propose a new debate