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DESCRIPTION
TOPIC. EFFECT OF DEXMEDETOMIDINE AS AN ADJUVANT TO EPIDURAL ROPIVACAINE 0.75%. DR.Rajaram MD(Final). NAME: DR.J.RAJARAM. COURSE: MD FINAL(ANESTHESIA). CENTER: KILPAUK MEDICAL COLLEGE & HOSPITAL. GUIDE: DR.P.S.SHANMUGAM MD.DA PROF & HOD OF ANESTHESIA - PowerPoint PPT PresentationTRANSCRIPT
TOPIC
EFFECT OF DEXMEDETOMIDINE AS AN ADJUVANT TO EPIDURAL ROPIVACAINE
0.75%
DR.Rajaram MD(Final)
NAME : DR.J.RAJARAM
COURSE : MD FINAL(ANESTHESIA)
CENTER : KILPAUK MEDICAL COLLEGE & HOSPITAL
GUIDE : DR.P.S.SHANMUGAM MD.DA PROF & HOD OF ANESTHESIA DEPT OF ANESTHESIA KILPAUK MEDICAL COLLEGE
INTRODUCTION
Hypothesis of this study is to evaluate and compare the effect of added dexmedetomidine to epidural ropivacaine 0.75%
40 patients under going elective lower limb orthopedic procedures under epidural were selected and divided into two groups of 20 each
Control group- epidural ropivacaine 0.75% 20ml (150mg)
Dex group- epidural ropivacaine 0.75% 20ml (150mg) + Dexmedetomidine 1μg/kg
METHODS
Ethical committee approval Informed consent Randomised double blind study 40 paients under going elective
orthopedic procedures were selected Absolute fasting of 8 hours , without
premedication
METHODS
ASA I & II BOTH SEXES AGE BETWEEN 18-70
yrs ELECTIVE ORTHOPEDIC
PROCEDURE UNDER EPIDURAL
ANESTHESIA WITHOUT COMORBID
ILLNESS
ALLERGY TO LOCAL ANESTHETICS
NM DISEASES USING α2
ANTAGONISTS WEIGHT MORE THAN
120 kg
INCLUSION CRITERIA EXCLUSION CRITERIA
CONTD..
I.V line secured for administration of RL,10ml/kg/hr
Monitors include pulse oximetry, NIBP, ECG
Epidural Performed with 16G Tuohy needle Lumbar epidural space Sitting position Loss of resistance technique
GROUPS
CONTROL GROUP(N=20) : Epidural ropivacaine 0.75% 20ml(150mg)+1 ml
NS DXMEDETOMIDINE GROUP(N=20) :
Epidural ropivacaine 0.75% 20ml(150mg)+ Dexmedetomidine 1μg/kg+NS to complete 1ml
20ml 0.75% injected at the rate of 1ml/3sec Patients were treated with titrated doses
ephedrine 6mg if systolic BP<90mmhg, with atropine 0.6mg if HR<60/min
Patients were sedated on demand basis
VARIABLES
BLOCK ONSET TIME MAXIMUM DERMATOMAL LEVEL OF ANESTHESIA DURATION OF SENSORY AND MOTOR
BLOCKADE MOTOR BLOCK INTENSITY-BROMAGE MOTOR
SCALE SENSORY BLOCK-SENSORY SCALE LEVEL OF SEDATION-RAMSEY SEDATION SCALE HEMODYNAMICS DURATION POST OPERATIVE ANALGESIA-VAS
SCORE
DEFINITION OF VARIABLES
SENSORY BLOCK ONSET TIME Time interval between end of anesthetic injection and
appearance of cutaneous analgesia in dermatomes T-12,T-10,T-8,T-6
DURATION OF MOTOR BLOCK Administration of anesthetic and attainment of grade 0 in
Bromage motor scale DURATION OF ANALGESIA
Administration of anesthetic and disappearance of cutaneous level at each dermatomal level
POST-OP ANALGESIA DURATION Administration of anesthetic and time of analgesic usage in
PACU SUPPLEMENTAL SEDATION
If patient felt pain or uncomfortable , with pentazocine 0.3mg/kg and or midazolam 0.02mg I.V
BROMAGE MOTOR SCALE
GRADE CRITERIA DEGREE OF BLOCK
0 FREE MOVEMENT OF LEGS AND FEET
NIL(0%)
1 JUST ABLE TO FLEX KNEES WITH FREE MOVEMENT OF KNEES
PARTIAL(33%)
2 UNABLE TO FLEX KNEES,BUT WITH MOVEMNT OF FEET
ALMOST COMPLETE (66%)
3 UNABLE TO MOVE LEGS OR FEET COMPLETE (100%)
RAMSEY SEDATION SCALE
SENSORY SCORE
SCORE RESPONSE
0 NORMAL SENSATION
1 ANALGESIA(LOSS OF PIN PRICK SENSATION)
2 ANESTHESIA(LOSS OF TOUCH)
STATISTICS
Variables were analyzed with Student ‘t’ test, Chi Square test
Variables like age, sex, weight, height were compared using Levene’s test for equality of variance
Sample size obtained according to previous background study
‘p’ value less than 0.05 was taken as significant
RESULTS
One patient in control group was excluded for failure of epidural block and need for GA
Distributions of age, weight, height, sex and type of surgery , duration of surgery between groups(p>0.05)
Block onset time T-12,T-10,T-8,T6 between groups-shortened onset time, with less significance(p<0.08)
Regression time is prolonged in dex group(p<0.01) Maximal level of analgesia assessed after 60mins
between groups were T-4 to T-6, without significance
Block Onset Time
Regression Time
Upper Level Of Analgesia
SEX DISTRIBUTION
DISTRIBUTION OF SURGERY
EPIDURAL CATHETER LENGTH
VARIABLES CONTROL DEXAge 42.25 39.10
SexFemale 3 4Male 17 16
Height (cm) 169.35 163.15Weight (kg) 69.95 66.75
Level Of EpiduralL1-L2 2 2L2-L3 10 10L3-L4 8 8
Cathetar Length (cm) 6.5 6.85
Surgery
IM / IL Nailing 10 9Illizarao ring fixation 4 2DHS 2 5TKR 1 1THR 1 0DCS 0 1Encirclage / TBW L Patella 1 0Plate & Screw fixation 0 2Hemiarthroplasty 1 0
ASAI 12 15II 8 5
DURATION OF SURGERY (mins) 158.25 177
CONTD..
Duration of analgesia-prolonged in Dex group, level of significance-(p<0.05)
Motor block duration-prolonged in Dex group, level of significance(p<0.05)
Intensity of motor block-increased intensity in dex group,without significance(p<0.37)
Supplemental sedation-reduced need in Dex group , level of significance Patient given supplemental mask O2 if SpO2
<94% Duration of post-op analgesia-significantly
prolonged in Dex group, level of significance (p<0.01)
VARIABLES CONTROL DEX ‘P’ VALUE
Block Onset Time (T-12)mins 13.90 12.45 0.085
Duration Of Analgesia (mins) 236.35 304.25 0.021
Regression Time 115.55 177.30 0.051
Motor Block Duration (mins) 204.65 248.00 0.042
Post Of Analgesia (mins ) 309 496.95 0.001
Contd..
Need for vasopressors- similar between groups with out much significance(p>0.13) Occurrence of hypotension with need for
vasopressor Occurrence of bradycardia and need for vagolytic
Hemodynamic stability-stable in both groups without much significance(p<0.06)
Occurrence of other complications like shivering, nausea , RS depression in intra and post-op period –similar between groups
Epidural catheter was used for giving rescue analgesia with 0.2% ropivacaine 10ml (20mg)
SEDATIVE USAGE
ROPIVACAINE
ROPIVACAINE
It is a long acting amide local anesthetics Ropivacaine is ‘S’ isomer of the propyl analogue of
mepivacaine and bupivacaine Similar to bupivacaine ,but with better cadiotoxicity
profile, dissociates from Na+channels more rapidly Produces less accumulation of Na+channel block
Significantly better sensory-motor differentiation,due to lower lipid solubility than bupivacaine
Has mild intrinsic vasoconstricting properties unsuitable for infiltration in tissues without collateral
blood supply Reason for longer cutaneous anesthesia
PROPERTIES-ROPIVACAINE
pKa is 8.07 Protein binding is 94% Partition co-efficient is 115 CC:CNS ratio is 5:1 Potency 4
DISCUSSION
According to result, There is a synergistic interaction of dex and
ropivacaine during epidural administration Addition of Dex prolongs analgesic and
motor blockade duration and post-op analgesia
Decreases the requirement of supplemental sedation
It does not affect onset time
DEXMEDETOMIDINE
DEXMEDETOMIDINE
Dex is an agonist of α2 adrenergic receptor – agonist where ratio among α2 : α1 is 1600:1
Dex epidural effect is dose dependent and superior than I.V due to its high affinity for α2 adrenergic receptors in spinal cord
Dex first administered epidurally in 1997, combined with 1.5% lignocaine for patients undergoing hystrectomy
8 times greater selectivity than clonidine towards α2 adrenergic receptor
DEX..
After epidural administration of Dex , it is rapidly detected in CSF within five mins,however only 22% is absorbed into intra thecal space Dex inhibition of locus caeruleus results in
disinhibition of of NA nuclei and exerts descending inhibitory effect on nociception in spical cord
Anti-nociceptive effect is Dose dependent Related to affinity of located α2 in spinal card Higher lipid solubility
Prolonged analgesic action of LA is due to Reduced systemic absorbtion caused by local
vasoconstriction mediated byα2C in smooth muscle of epidural venous plexus
DEX..
Sedative effect of Dex, Mediated by binding to α2A receptors in locus caeruleus Diminishes release of norepinephrine During epidural administration cephalad spread into
meninges may be responsible for sedation Dex cause more sensory than motor block duration
4 times the dose is required for inhibition large ,myelinated Aα fibers when compared to small unmyelinated C fibers
Bradycardia Is dose dependent Occurs in epidural if level is higher
Shivering incidence may be reduced with α2 agonists due to central inhibition of thermoregulatory centre
CONCLUSION
DEX has significant synergistic interaction with epidural Ropivacaine in Prolonging duration of analgesia(p<0.02) Prolonging duration motor block(p<0.04) Post-op duration of analgesia(p<0.001)
Ref. brazilia scandinavia ,journal
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