Tracheal intubating conditions in elderly patients when train-of-four count is zero after rocuronium 0.6 or 0.9 mg/kg. A secondary analysis.

PURPOSE: The neuromuscular blocking agent rocuronium can be administered to facilitate tracheal intubation. We hypothesized that rocuronium 0.9 mg/kg provided a larger proportion of patients with vocal cords in abducted position compared to rocuronium 0.6 mg/kg at train-of-four (TOF) 0. METHODS: This secondary analysis was based on 52 elderly surgical patients of which 36 patients received rocuronium 0.6 mg/kg and 16 patients received rocuronium 0.9 mg/kg. Neuromuscular block was monitored with acceleromyography with TOF stimulation at the ulnar nerve. The primary outcome was the proportion of patients with vocal cords in abducted position at TOF 0. Secondary outcomes were intubating conditions evaluated by the Fuchs-Buder scale, the Intubating Difficulty Score (IDS), onset time, and duration of action of rocuronium. RESULTS: At TOF 0, a significantly larger proportion of patients had vocal cords in abducted position in the rocuronium 0.9 mg/kg group (81%) compared with the rocuronium 0.6 mg/kg group (53%); difference (%) 28, 95% Cl 3-53, P = 0.05. Excellent intubating conditions (Fuchs-Buder) were more common in the rocuronium 0.9 mg/kg group (62.5%); difference (%) 32.5, 95% Cl 4-61), P = 0.03. No significant difference was found in IDS or onset time of rocuronium (difference 19 s, 95% Cl: -5-43). Duration of action was significantly longer (difference 29 min, 95% Cl: 10-47) in the 0.9 mg/kg group. CONCLUSION: The proportion of patients with vocal cords in abducted position was significantly larger after rocuronium 0.9 mg/kg compared to rocuronium 0.6 mg/kg at TOF 0 monitored at the ulnar nerve.

Comparison of onset time, duration of action, and intubating conditions after cisatracurium 0.15 mg/kg in young and elderly patients.

INTRODUCTION: Tracheal intubation during anesthesia can be facilitated by the neuromuscular blocking agent cisatracurium. However, limited data exists about onset time, duration of action and effect on intubating conditions in elderly patients above 80 years of age. We hypothesized that elderly patients would present a longer onset time and duration of action compared to younger adults. METHODS: This prospective observational study included 31 young (18-40 years) and 29 elderly (≥ 80 years) patients. Patients were given fentanyl 2 µg/kg and propofol 1.5-2.5 mg/kg for induction of anesthesia and maintained with remifentanil and propofol. Monitoring of neuromuscular function was performed with acceleromyography. Primary outcome was onset time defined as time from injection of cisatracurium 0.15 mg/kg (based on ideal body weight) to a train-of-four (TOF) count of 0. Other outcomes included duration of action (time to TOF ratio ≥ 0.9), intubation conditions using the Fuchs-Buder scale and the Intubating Difficulty Scale (IDS), and occurrence of hoarseness and sore throat postoperatively. RESULTS: Elderly patients had significantly longer onset time compared with younger patients; 297 seconds (SD 120) vs. 199 seconds (SD 59) (difference: 98 seconds (95% CI: 49-147), P < 0.001)). Duration of action was also significantly longer in elderly patients compared with younger patients; 89 minutes (SD 17) vs. 77 minutes (SD 14) (difference: 12 minutes (95% CI: 2.5-20.5) P = 0.01)). No difference was found in the proportion of excellent intubating conditions (Fuchs-Buder); 19/29 (66%) vs 21/31 (68%) (P = 0.86) or IDS score (P = 0.74). A larger proportion of elderly patients reported hoarseness 24 hours postoperatively; 62% vs 34% P = 0.04. CONCLUSION: In elderly patients cisatracurium 0.15 mg/kg had significantly longer onset time and duration of action compared with younger patients. No difference was found in intubating conditions at a TOF count of 0. TRIAL REGISTRATION: Clinicaltrials.gov (NCT04921735, date of registration 10 June 2021).