Dr Kapil Gupta,
Associate Professor, Department of Anaesthesia and Critical care,
V.M.M.C & Safdarjung Hospital, New Delhi-110029, INDIA
Mobile: 91-9811859019 Fax: 91-11-45626460
Type of manuscript – Research manuscript
TITLE -COMPARATIVE EVALUATION OF ISOBARIC ROPIVACAINE (0.75%) WITH ADJUVANT – CLONIDINE AND DEXMEDETOMIDINE ADMINISTERED INTRATHECALLY IN ADULT PATIENTS UNDERGOING INFRA-UMBLICAL SURGERIES
Author- Dr Kapil Gupta, Associate Professor, Anesthesia, VMMC & Safdarjung Hospital, Delhi
Key words - Regional anaesthesia, analgesia, adjuvant
Work done in:
Department of Anaesthesia and Critical care,
V.M.M.C & Safdarjung Hospital,
New Delhi-110029, INDIA
IMPORTANT NOTE- THIS USE OF DEXMEDETOMIDINE INTRATHECALLY IS ‘OFF LABEL’
Introduction: Ropivacaine is widely used for regional anaesthesia and different adjuvants are added to prolong its sensory and motor block, with good safety profile (1, 2). The alpha agonists like clonidine, dexmedetomidineand ephedrine, are assuming greater importance as anaesthetic adjuvants to local anaesthetics and opioids. They provide neuraxial analgesia via alpha-adrenergic receptors and opioid independent mechanisms (3).Intrathecal α-2 -receptor agonists are found to have antinociceptive action for both somatic and visceral pain (4).
Objective: We conducted a double blind, randomized, study to evaluate the efficacy and safety profile of clonidine or dexmedetomidine, added as adjuvant to intrathecal ropivacaine.
Methods: Ninety ASA I/II patients of age 18-65 yrs with height 150-180cm and weight 50-75 kg scheduled to undergo infra-umbilical surgery, were randomized into three groups of 30 each:
- Group RS - They were administered 3.0ml of 0.75% isobaric Ropivacaine + 0.2ml of Isotonic Saline intrathecally
- Group RC - They were administered 3.0ml of 0.75% isobaric Ropivacaine + 30µg of Clonidine intrathecally
- Group RD - They were administered 3.0ml of 0.75% isobaric Ropivacaine + 5µg of Dexmedetomidine intrathecally
The following variables were recorded:
- Time to onset of sensory block to T10 and T8 dermatomal levels (time between injection and no sensation to prick at T10 and T8 levels).
- Maximum upper dermatomal level of sensory block and time taken to achieve it.
- Duration of sensory block (time between injection and recovery to L1 dermatomal level).
- Total duration of analgesia (time between the injection and first request for analgesia).
- Time to onset of maximum degree of motor block (complete motor block).
- Total duration of motor block ( from initial onset until complete recovery)
- Heart Rate, Blood Pressure (SBP, DBP, MBP).
Results: Total duration of analgesia was significantly higher in RD group, compared to RC group (379.33 ± 32.39 mins vs 344.97 ± 42.91 mins)( p<0.001) (Figure 1). Total duration of motor block was 177.10 mins, 246.70 mins and 231.63 mins in groups RS, RC and RD respectively (Figure 2) (p<0.001). Total duration of sensory block was maximum in group RC (239 min) and minimum in group RS (174 min); and was found to be statistically significant among the three groups (Figure 3) ( p<0.001). Time to onset of maximum sensory block and motor block was minimum in RC group (Figure 4 & 5). There was no episode of hypotension or bradycardia in any of the three groups.
Discussion & Conclusion: Both drugs, clonidine and dexmedetomidine can be safely added as adjuvant to intrathecal ropivacaine, in view of similar sensory and motor block characteristics. Our study concluded that dexmedetomidine is superior to clonidine, as intrathecal adjuvant to plain isobaric ropivacaine as it significantly prolonged the sensory and motor block, even greater than clonidine. The onset of action of motor and sensory block is faster with clonidine, compared to dexmedetomidine.
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