EFFECT OF DEXMEDETOMIDINE AS AN ADJUVANT TO EPIDURAL ROPIVACAINE 0.75%

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

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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

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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 a2 ANTAGONISTS
• WEIGHT MORE THAN 120 kg

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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

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GROUPS

• CONTROL GROUP(N20)
• Epidural ropivacaine 0.75 20ml(150mg)1 ml NS
• DXMEDETOMIDINE GROUP(N20)
• Epidural ropivacaine 0.75 20ml(150mg)
  Dexmedetomidine 1µg/kgNS to complete 1ml
• 20ml 0.75 injected at the rate of 1ml/3sec
• Patients were treated with titrated doses
  ephedrine 6mg if systolic BPlt90mmhg, with
  atropine 0.6mg if HRlt60/min
• Patients were sedated on demand basis

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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

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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

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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)
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RAMSEY SEDATION SCALE
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SENSORY SCORE
SCORE RESPONSE
0 NORMAL SENSATION
1 ANALGESIA(LOSS OF PIN PRICK SENSATION)
2 ANESTHESIA(LOSS OF TOUCH)
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STATISTICS

• Variables were analyzed with Student t test,
  Chi Square test
• Variables like age, sex, weight, height were
  compared using Levenes test for equality of
  variance
• Sample size obtained according to previous
  background study
• p value less than 0.05 was taken as significant

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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(pgt0.05)
• Block onset time T-12,T-10,T-8,T6 between
  groups-shortened onset time, with less
  significance(plt0.08)
• Regression time is prolonged in dex group(plt0.01)
• Maximal level of analgesia assessed after 60mins
  between groups were T-4 to T-6, without
  significance

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Block Onset Time
Regression Time
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Upper Level Of Analgesia
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SEX DISTRIBUTION
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DISTRIBUTION OF SURGERY
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EPIDURAL CATHETER LENGTH
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VARIABLES CONTROL DEX
Age Age 42.25 39.10
Sex Female 3 4
Sex Male 17 16
Height (cm) Height (cm) 169.35 163.15
Weight (kg) Weight (kg) 69.95 66.75
Level Of Epidural L1-L2 2 2
Level Of Epidural L2-L3 10 10
Level Of Epidural L3-L4 8 8
Cathetar Length (cm) Cathetar Length (cm) 6.5 6.85
Surgery IM / IL Nailing 10 9
Surgery Illizarao ring fixation 4 2
Surgery DHS 2 5
Surgery TKR 1 1
Surgery THR 1 0
Surgery DCS 0 1
Surgery Encirclage / TBW L Patella 1 0
Surgery Plate Screw fixation 0 2
Surgery Hemiarthroplasty 1 0
ASA I 12 15
ASA II 8 5
DURATION OF SURGERY (mins) DURATION OF SURGERY (mins) 158.25 177
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CONTD..

• Duration of analgesia-prolonged in Dex group,
  level of significance-(plt0.05)
• Motor block duration-prolonged in Dex group,
  level of significance(plt0.05)
• Intensity of motor block-increased intensity in
  dex group,without significance(plt0.37)
• Supplemental sedation-reduced need in Dex group ,
  level of significance
• Patient given supplemental mask O2 if SpO2 lt94
• Duration of post-op analgesia-significantly
  prolonged in Dex group, level of significance
  (plt0.01)

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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 
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Contd..

• Need for vasopressors- similar between groups
  with out much significance(pgt0.13)
• Occurrence of hypotension with need for
  vasopressor
• Occurrence of bradycardia and need for vagolytic
• Hemodynamic stability-stable in both groups
  without much significance(plt0.06)
• 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)

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SEDATIVE USAGE
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ROPIVACAINE
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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 Nachannels more rapidly
• Produces less accumulation of Nachannel 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

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PROPERTIES-ROPIVACAINE

• pKa is 8.07
• Protein binding is 94
• Partition co-efficient is 115
• CCCNS ratio is 51
• Potency 4

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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

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DEXMEDETOMIDINE
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DEXMEDETOMIDINE

• Dex is an agonist of a2 adrenergic receptor
  agonist where ratio among a2 a1 is 16001
• Dex epidural effect is dose dependent and
  superior than I.V due to its high affinity for
  a2 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 a2 adrenergic receptor

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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 a2 in spinal card
• Higher lipid solubility
• Prolonged analgesic action of LA is due to
• Reduced systemic absorbtion caused by local
  vasoconstriction mediated bya2C in smooth muscle
  of epidural venous plexus

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DEX..

• Sedative effect of Dex,
• Mediated by binding to a2A 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 Aa 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 a2
  agonists due to central inhibition of
  thermoregulatory centre

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CONCLUSION

• DEX has significant synergistic interaction with
  epidural Ropivacaine in
• Prolonging duration of analgesia(plt0.02)
• Prolonging duration motor block(plt0.04)
• Post-op duration of analgesia(plt0.001)
• Ref. brazilia scandinavia ,journal

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THANK U