1. EFFECT OF DEXMEDETOMIDINE AS AN ADJUVANT TO EPIDURAL ROPIVACAINE 0.75%
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 ALLERGY TO LOCAL ANESTHETICS NM DISEASES USING α2 ANTAGONISTS
INCLUSION CRITERIA
EXCLUSION CRITERIA
ASA I & II
BOTH SEXES
AGE BETWEEN 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) : DXMEDETOMIDINE 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 GRADE CRITERIA DEGREE OF BLOCK
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%)

11. RAMSEY SEDATION SCALE

12. SENSORY SCORE SCORE RESPONSE NORMAL SENSATION 1
NORMAL SENSATION 1
ANALGESIA(LOSS OF PIN PRICK SENSATION) 2
ANESTHESIA(LOSS OF TOUCH)

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. Block Onset Time
Regression Time

16. Upper Level Of Analgesia

17. SEX DISTRIBUTION

18. DISTRIBUTION OF SURGERY

19. EPIDURAL CATHETER LENGTH

20. VARIABLES
CONTROL
DEX
Age
42.25
39.10
Sex
Female 3 4
Male 17 16
Height (cm)
169.35
163.15
Weight (kg)
69.95
66.75
Level Of Epidural
L1-L2 2
L2-L3 10
L3-L4 8
Cathetar Length (cm)
6.5
6.85
Surgery
IM / IL Nailing 9
Illizarao ring fixation
DHS 5
TKR 1
THR
DCS
Encirclage / TBW L Patella
Plate & Screw fixation
Hemiarthroplasty
ASA I 12 15 II
DURATION OF SURGERY (mins)
158.25
177

21. 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)

22. Block Onset Time (T-12)mins 13.90 12.45 0.085
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 

24. 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)

25. SEDATIVE USAGE

26. ROPIVACAINE

27. 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

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

29. 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

30. DEXMEDETOMIDINE

32. 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

33. 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

34. 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

35. 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

36. THANK U