Saline Flush After Rocuronium Bolus Reduces Onset Time and Prolongs Duration of Effect: A Randomized Clinical Trial

Ishigaki, Sayaka MD; Masui, Kenichi MD, PhD; Kazama, Tomiei MD, PhD

doi: 10.1213/ANE.0000000000001094
Anesthetic Pharmacology: Research Report

BACKGROUND: Circulatory factors modify the onset time of neuromuscular-blocking drugs. Therefore, we hypothesized that infusion of a saline flush immediately after rocuronium administration would shorten the onset time without influencing the duration of the rocuronium effect.

METHODS: Forty-eight patients were randomly allocated to the control or saline flush group. Anesthesia was induced and maintained with propofol and remifentanil, and all patients received 0.6 mg/kg rocuronium in 10 mL of normal saline. In the saline flush group, 20 mL normal saline was immediately infused after rocuronium administration. Neuromuscular blockade was assessed using acceleromyography at the adductor pollicis muscle with train-of-four (TOF) stimulation. The neuromuscular indices for rocuronium were calculated as follows: the latent onset time, defined as the time from the start of rocuronium infusion until first occurrence of depression of the first twitch of the TOF (T1) ≥5%; onset time, defined as the time from the start of rocuronium infusion until first occurrence of depression of the T1 ≥95%; clinical duration, defined as the time from the start of rocuronium administration until T1 recovered to 25% of the final T1 value; recovery index, defined as the time for recovery of T1 from 25% to 75% of the final T1 value; and the total recovery time, defined as the time from the start of rocuronium administration until reaching a TOF ratio of 0.9. Significance was designated at P <0.05.

RESULTS: The measured latent onset time and onset time were significantly shorter in the saline flush group than the control group by 15 seconds (95.2% confidence interval, 0–15, P = 0.007) and 15 seconds (0–30, P = 0.018), respectively. Saline flush significantly depressed the T1 height at 30, 45, and 60 seconds after the rocuronium bolus by 17%, 24%, and 14%, respectively. In addition, the recovery phase was significantly prolonged in the saline flush group. The mean clinical duration (5th–95th percentile range) in the saline flush group and control group was 35 minutes (27–63 minutes) and 31 minutes (19–48 minutes; P = 0.032), respectively; the recovery index was 13 minutes (8–25 minutes) and 10 minutes (7–19 minutes; P = 0.019), respectively; and the total recovery time was 61 minutes (44–108 minutes) and 50 minutes (35–93 minutes; P = 0.048), respectively.

CONCLUSIONS: Administering a 20-mL saline flush immediately after infusion of 0.6 mg/kg rocuronium in 10 mL normal saline shortened the onset time and prolonged the recovery phase of neuromuscular blockade.

Published ahead of print November 23, 2015

From the Department of Anesthesiology, National Defense Medical College, Tokorozawa, Saitama, Japan.

Accepted for publication October 6, 2015.

Published ahead of print November 23, 2015

Funding: Departmental/institutional.

The authors declare no conflicts of interest.

This report was previously presented in part at the 14th Eurosiva Annual Scientific Meeting in Amsterdam on June 10, 2011, and at the 51st annual scientific meeting of a local branch of the Japanese Society of Anesthesiologists in Chiba, September 10, 2011.

Reprints will not be available from the authors.

Address correspondence to Kenichi Masui, MD, PhD, Department of Anesthesiology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359–8513, Japan. Address e-mail to kenichi@masuinet.com.

© 2016 International Anesthesia Research Society