Prospective comparative randomized controlled study to determine the optimal priming dose of atracurium

Introduction: The advantages of the use of muscle relaxants in the current practice of balanced anesthesia are well documented. Most often, nondepolarizing muscle relaxants (NDMR) with minimal side effects are used to serve the purpose. Atracurium is a commonly used NDMR in day-to-day anesthetic practice, although it is not desirable for rapid sequence induction and intubation due to its late onset of action. To overcome this problem priming principle was introduced. Aim: This study aims to determine optimal priming dose of atracurium to speed up the onset of action. Patients and Methods: In this prospective randomized controlled study, 90 patients were allocated into one of the three groups by a computer-generated table of random numbers, i.e., Group A, B, and C. Total dose of atracurium used in all patients was 0.5 mg/kg body weight, including the priming dose. Each group received different priming doses of atracurium as follows: Group A received 0.05 mg/kg body weight, Group B received 0.025 mg/kg body weight, whereas Group C (control) received saline as priming dose. Results: Patients were comparable with respect to demographic data. The mean duration in seconds for train-of-four (TOF) count to reach zero were 147 s, 193, and 218 s in Group A, B, and C, respectively, with statistically significant P values. Of 60 patients who were administered atracurium as priming drug, two patient had ptosis at the end of 3 min after priming with 0.05 mg/kg body weight, with no other side effects. Conclusions: Priming principle employing atracurium reduces the time required for TOF count to reach zero by approximately 71 s while using 0.05 mg/kg body weight and by around 25 s while employing 0.025 mg/kg body weight, with clinically insignificant incidence of adverse effects