Sample size considerations for studies comparing intubating conditions using quantitative monitoring versus a fixed interval during onset of neuromuscular blockade.

INTRODUCTION: Data in the literature are still scarce to establish any recommendations on the use of quantitative monitoring during tracheal intubation. PATIENTS AND METHODS: In this monocentric study, non-morbidly obese adult female patients without risk factors for difficult tracheal intubation were prospectively included. After 0.5 mg.kg-1 atracurium during propofol-sufentanil anaesthesia, intubation conditions were evaluated using the Copenhague and Cormack-Lehane classification at the complete twitch suppression at the TOF to the AP (monitor group) or after a fixed 3 min waiting time after atracurium injection (3-min group). We also examined sample size for future studies. RESULTS: We included 102 (monitor group) and 97 (3-min group) adult non-obese female patients without different characteristics. Intubation conditions were acceptable in 96/102 (94%) in the monitor group vs. 84/97 (87%) in the 3-min group, p = 0.07. The presence of a Cormack and Lehane view of 1 was marginally better in the monitor group as compared to the 3-min group, p = 0.041. We propose two possibility of sample size based on a difference of observed events based on acceptable intubation conditions, n = 602, or on excellent intubation conditions, n = 550. DISCUSSION: This observational study shows that the use of a neuromuscular TOF monitoring of the ulnar nerve as compared to a fixed 3-min waiting time after atracurium injection could improve laryngoscopic view and show a tendency to better intubation conditions without conclusive statistical significance. We suggest that researchers consider our recommendations in terms of the sample size to include in their future research, keeping in mind the limitations of our study.

Use of Neuromuscular Blockers During Therapeutic Hypothermia After Cardiac Arrest: A Nursing Protocol.

BACKGROUND: Neuromuscular blockers used to prevent shivering during therapeutic hypothermia in comatose patients after out-of-hospital cardiac arrest are associated with adverse events. OBJECTIVE: To assess the influence of a nurse-implemented protocol on use of neuromuscular blockers in patients treated with 24-hour therapeutic hypothermia after out-of-hospital cardiac arrest. METHODS: A before and after study was done in a 24-bed cardiac arrest center. During the before period, paralysis was maintained by continuous infusion of vecuronium during therapeutic hypothermia. During the after period, a nurse-implemented protocol was used to strictly control use of neuromuscular blockers. The primary outcome measure was duration of infusion of neuromuscular blockers; secondary end points included rates of ventilator-associated pneumonia and intensive care unit mortality. RESULTS: Among the 22 patients in the before group and the 23 patients in the after group, most were men (78%) with a median age of 66 years. Baseline characteristics were similar between the 2 groups. Median duration of sedation was 36 hours, shorter in the after group (34 hours) than in the before group (38 hours; P = .02). Median duration of infusion of neuromuscular blockers was significantly shorter in the after group (6 hours) than in the before group (33 hours; P < .001). Ventilator-associated pneumonia occurred more frequently in the before group (45%) than in the after group (13%; P = .02). Overall intensive care unit mortality rate was 58%, similar in both groups (P = .44). CONCLUSION: Use of a nurse-implemented protocol to reduce use of neuromuscular blockers is feasible.