Effects of cardiac output on the onset of rocuronium-induced neuromuscular block in elderly patients

Rocuronium action can be affected by hyperventilation: a case report and computational simulation

The neuromuscular blocking potency of rocuronium varies with respiratory pH changes, increasing at lower pH and decreasing at higher pH; thus, hyperventilation-induced respiratory alkalosis is expected to decrease the potency of rocuronium. We report a case of anesthetic management of modified electroconvulsive therapy (m-ECT) for a patient monitored with electromyography-based neuromuscular monitoring during two patterns of ventilation to elucidate their relationship and propose the possible mechanisms underlying the effects by computational simulations. Case presentation: The patient was a 25-year-old man with schizophrenia. In m-ECT, hyperventilation may be used to produce longer seizures. We compared the neuromuscular monitoring data recorded during hyperventilation and during normal ventilation while receiving the same dose of rocuronium. Despite receiving the same dose of rocuronium, the time required for the first twitch to decrease to 80% of the control value was delayed in hyperventilation compared to normal ventilation. Conclusions: This case report and computational simulation suggest that respiratory alkalosis might delay the action of rocuronium. It is necessary to consider the delayed action of rocuronium when hyperventilation is performed.

Rocuronium ≤1.5 mg/kg versus >1.5 mg/kg and inadequate paralysis in prehospital and retrieval intubation: A retrospective study

OBJECTIVE

Greater Sydney Area Helicopter Emergency Medical Service encouraged an increased dose of rocuronium for rapid sequence intubations (RSIs) from 1.5 mg/kg to 2.0 mg/kg from the end of 2017 in response to a number of inadequately paralysed patients identified by our airway audit processes. Subsequent protocol change incorporated 2.0 mg/kg rocuronium. This retrospective observational study was undertaken to see if doses over 1.5 mg/kg rocuronium were associated with a reduction in the number of inadequately paralysed patients.

METHODS

Retrospective review of patient prehospital notes and airway database records from 2017 to 2018 for all cases using rocuronium for RSI. Primary outcome of interest was physician notes describing skeletal muscle activity at laryngoscopy. Patients with tissued vascular access were excluded. Dose of rocuronium, estimated patient actual weight and grade of laryngoscopy were recorded. Comparisons were made between rocuronium doses ≤1.5 mg/kg and >1.5 mg/kg by estimated weight.

RESULTS

From 211 patients receiving rocuronium ≤1.5 mg/kg, five cases were inadequately paralysed, compared with two cases from 384 patients receiving >1.5 mg/kg rocuronium.

CONCLUSIONS

Although there were fewer inadequately paralysed patients with rocuronium doses >1.5 mg/kg, this did not reach statistical significance, presumably because of the low event rate. Further investigation into rocuronium dose for RSI is warranted.

A blinded randomized study comparing intubating conditions after either rocuronium 0.6 mg·kg-1 or remifentanil 2 µg·kg-1 in elderly patients

BACKGROUND

To facilitate tracheal intubation, either a neuromuscular blocking agent or a bolus dose of remifentanil can be administered. We hypothesized that rocuronium 0.6 mg·kg^-1 provided a larger proportion of excellent intubating conditions compared to remifentanil 2 µg·kg^-1 in patients above 80 years.

METHODS

A total of 78 patients were randomized to either rocuronium 0.6 mg·kg^-1 or remifentanil 2 µg·kg^-1 . General anaesthesia was initiated with fentanyl and propofol. Two minutes after the administration of either rocuronium or remifentanil, tracheal intubating conditions were evaluated using the Fuchs-Buder scale by a blinded investigator, and our primary outcome was the proportion of patients presenting intubating conditions deemed as excellent. Further outcomes included the Intubating Difficulty Scale (IDS), hoarseness or sore throat 24 h postoperatively, and intervention against hypotension.

RESULTS

No difference in the occurrence of excellent intubating conditions was found comparing the rocuronium group with the remifentanil group; 10 (28%) versus 15 (39%) (p = .29), respectively, relative risk = 0.72. Interventions against hypotension were used in 24 (67%) versus 28 (74%) (p = .51), respectively. Hoarseness and sore throat 24 h postoperatively were found in 37% versus 35% p = .86, and 14% versus 5% p = .20, respectively. The IDS score was 2 versus 2 p = .48.

CONCLUSION

No difference in intubating conditions was found 2 min after the administration of either rocuronium 0.6 mg·kg^-1 or remifentanil 2 µg·kg^-1 in patients aged above 80 years. Intubation conditions were less than optimal in a large proportion of this patient population.

CLINICAL TRIALS REGISTRATION

NCT04287426.

Neuromuscular block in patients 80 years and older: a prospective, controlled study

Background

An increasing number of patients older than 80 years are undergoing anesthesia, but little information is available regarding pharmacodynamic effects of myorelaxants in this population. This study aims to compare the time course of rocuronium neuromuscular block in patients ≥ 80 years with those of younger adults.

Methods

Under total intravenous anesthesia with propofol and sufentanil, time course of a bolus of rocuronium 0.6 mg/kg neuromuscular block was assessed with acceleromyography in patients ≥ 80 and in patients 20–50 years old. Onset time, clinical duration, duration until 90% and 100% recovery of baseline were determined.

Results

Data from 32 patients were analyzed, 16 were ≥ 80 years and 16 were 20–50 years old. Demographic data are shown in Table 1. In the group ≥ 80, onset time was 190 s ± 46 s compared to 123 s ± 40 s in the group 20–50, P < 0.001 and the clinical duration was 52 [48–69.5] min and 36 [34–41] min, respectively, P < 0.001. Duration to 90% recovery of baseline was 77.5 [71–88.5] min and duration to 100% recovery of baseline was 91.2 [82.2–98] min in patients ≥ 80 years and the corresponding values in the patients 20–50 years old were 53.5 [49–55.5] min and 59.5 [56.5–70.25] min, respectively, P < 0.001.

Conclusion

Compared to younger adults rocuronium shifted in patients ≥ 80 years from a rapid onset, intermediate acting compound to a slower onset, long-acting compound.

Trial registration

ClinicalTrials.gov identifier: NCT03551652 (29/05/2018).

High-dose rocuronium-induced paralysis of the adductor pollicis muscle facilitates detection of the timing for tracheal intubation in elderly patients: a randomized double-blind study

Purpose

Methods

Results

Conclusions

Onset time and duration of action of rocuronium 0.6 mg/kg in patients above 80 years of age: A comparison with young adults

BACKGROUND

The number of elderly is increasing, and a large proportion of these people will require surgery and anaesthesia. However, little data exist regarding rocuronium in patients above 80 years of age. The aim of this study was to determine the onset time and duration of action for rocuronium 0.6 mg/kg in patients above 80 years compared with young adults.

METHODS

This prospective observational study included 16 young (18-40 years) and 16 elderly (>80 years) patients scheduled for total intravenous anaesthesia. Neuromuscular block following rocuronium 0.6 mg/kg was monitored with acceleromyography using train-of-four (TOF) stimulation. The primary outcome was onset time (from administration of rocuronium until TOF count = 0). Secondary outcomes were duration of action (from administration to TOF ratio >0.9) and intubating conditions according to Intubation Difficulty Score.

RESULTS

Elderly patients, median age of 84 years, had significantly prolonged onset time compared to younger patients; median 135 seconds (135-158) vs 90 seconds (90-105), respectively, a mean difference of 82 seconds (40-124) and Wilcoxon Mann-Whitney odds (WMW) of 19.48 (7.48-X). Duration of action in elderly patients was significantly longer, with a median time of 81 minute (71-97) vs 53 minute (42-73), respectively, a mean difference of 31 minute (14-48), and WMW odds of 6.35 (2.59-X). There was no significant difference in intubating conditions.

CONCLUSIONS

Patients above 80 years had significantly prolonged onset time and duration of action after rocuronium 0.6 mg/kg compared with patients aged 18-40 years.