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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

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  1. TOPIC EFFECT OF DEXMEDETOMIDINE AS AN ADJUVANT TO EPIDURAL ROPIVACAINE 0.75% DR.Rajaram MD(Final)

  2. 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

  3. 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

  4. 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

  5. METHODS INCLUSION CRITERIA EXCLUSION CRITERIA • 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. BROMAGE MOTOR SCALE

  11. RAMSEY SEDATION SCALE

  12. SENSORY SCORE

  13. 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

  14. 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

  15. SEX DISTRIBUTION

  16. DISTRIBUTION OF SURGERY

  17. EPIDURAL CATHETER LENGTH

  18. 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)

  19. 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)

  20. SEDATIVE USAGE

  21. ROPIVACAINE

  22. 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

  23. PROPERTIES-ROPIVACAINE • pKa is 8.07 • Protein binding is 94% • Partition co-efficient is 115 • CC:CNS ratio is 5:1 • Potency 4

  24. 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

  25. DEXMEDETOMIDINE

  26. 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

  27. 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

  28. 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

  29. 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

  30. THANK U

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