Susanta Sarkar

Bispectral index score and observer's assessment of awareness/sedation score may manifest divergence during onset of sedation: Study with midazolam and propofol

Background: Correlation between the clinical and electroencephalogram-based monitoring has been documented sporadically during the onset of sedation. Propofol and midazolam have been studied individually using the observers assessment of awareness/sedation (OAA/S) score and Bispectral index score (BIS). The present study was designed to compare the time to onset of sedation for propofol and midazolam using both BIS and OAA/S scores, and to find out any correlation. Methods: A total of 46 patients (18-60 years, either sex, American Society of Anesthesiologists (ASA) I/II) posted for infraumbilical surgeries under spinal anaesthesia were randomly allocated to receive either injection propofol 1 mg/kg bolus followed by infusion 3 mg/kg/h (Group P, n=23) or injection midazolam 0.05 mg/kg bolus followed by infusion 0.06 mg/kg/h (Group M, n=23). Spinal anaesthesia was given with 2.5 ml to 3.0 ml of 0.5% bupivacaine heavy. When sensory block reached T6 level, sedation was initiated. The time to reach BIS score 70 and time to achieve OAA/S score 3 from the start of study drug were noted. OAA/S score at BIS score 70 was noted. Data from 43 patients were analyzed using SPSS 12 for Windows. Results: Time to reach BIS score 70 using propofol was significantly lower than using the midazolam (P<0.05). Time to achieve OAA/S score 3 using propofol was comparable with midazolam (P=0.358). Conclusion: A divergence exists between the time to reach BIS score 70 and time to achieve OAA/S score 3 using midazolam, compared with propofol, during the onset of sedation.

A comparison of haemodynamic responses between clinical assessment-guided tracheal intubation and neuromuscular block monitoring-guided tracheal intubation: A prospective, randomised study

Background and Aims: Haemodynamic responses to laryngoscopy and endotracheal intubation and their hazards are well documented. The purpose of the study was to compare the effects of laryngoscopy and intubation on cardiovascular responses when the appropriate moment for intubation was directed by either clinical judgment or train-of-four assessment. Methods: A total of 68 patients, posted for laparoscopic cholecystectomy, were randomised into two groups. In Group M patients, the trachea was intubated after train of four counts became zero in adductor pollicis muscle, whereas in Group C patients, the trachea was intubated after the clinical judgment of jaw muscle relaxation. Changes in heart rate (HR) and mean arterial pressure, intubating conditions and the time between the administration of a neuromuscular blocking agent and endotracheal intubation were recorded. Results were analysed by the Analysis of variance and chi-square tests. Results: HR and mean arterial pressure were significantly higher in Group C as compared to Group M after laryngoscopy and tracheal intubation (P < 0.05). The mean time required for intubation was significantly shorter in Group C compared to Group M (175 ± 7 s vs. 385 ± 101 s). Excellent and good intubation conditions were observed in all Group M patients, whereas 24 out of 34 patients (70%) in Group C showed excellent and good intubation conditions. Conclusion: Haemodynamic responses to laryngoscopy and tracheal intubation can be significantly attenuated if tracheal intubation is performed following complete paralysis of laryngeal muscles, detected by neuromuscular monitoring of adductor pollicis muscle.