A study to assess the effect of intravenous dexmedetomidine oncis-atracurium induced neuromuscular blockade -A prospective double blind randomized controlled study

Abstract

Introduction: Ideal neuromuscular blocking agent should act through the mechanism of nondepolarizing agent, have rapid onset of action, be highly potent, have rapid recovery and completely reversible by cholinesterase inhibitors, should not release histamine, should have good hemodynamic stability, with pharmacologically inactive metabolites and effects should be non-cumulative. Materials and Methods: Sixty patients of ASA physical status 1 &2 aged 18-60 years of both gender undergoing general anaesthesia for surgery lasting less than 2 hours were randomly allocated into two groups (n=30), group D received dexmedetomidine 1μg/kg iv diluted to 10 ml infusion and group C received equal volume of normal saline infusion ten mins prior to propofol induction and both groups were relaxed with Inj cisatracurium 0.15mg/kg. Neuromuscular transmission was assessed by NMT (Avance GE). Time of onset of neuromuscular blockade i.e time to achieve TOF count 0, duration of neuromuscular blockade ( till TOF ratio of 0.6 / TOF count of 2) and recovery time that is time from administration of reversal at TOF ratio of ≥0.65/TOF 3 till extubation was noted. Infusion of normal saline or Inj dexmedetomidine 0.5μg/kg was started at the same rate via infusion pump during maintenance. Anaesthesia was maintained with oxygen, nitrous, isoflurane and Inj cisatracurium 0.03 mg/kg iv boluses for muscle relaxation. Results: In the control group mean duration was 46.80 ± 6.74 min and recovery time was 15.93 ± 2.79 min and in dexmedetomidine group mean duration was 60.40 ± 9.36 min and recovery time was 19.60 ± 2.82 min, which is statistically significant however there was no significant difference in mean time taken for onset of neuromuscular blockade. Conclusion: Intravenous dexmedetomidine prior to induction and during maintenance prolongs duration and recovery of cisatracurium induced neuromuscular blockade.