Ephedrine for Reducing Onset Time of Rocuronium in Elderly Patients: A Randomised Study

Onset time of rocuronium is prolonged in elderly patients compared to younger patients. Ephedrine reduces onset time of rocuronium in younger adults, but in elderly patients, the effect of ephedrine on onset time of rocuronium has not been investigated. The aim of this study was to determine the onset time of rocuronium 0.6 mg kg^-1 after administration of ephedrine 0.15 mg kg^-1 in patients aged 80 years or above. The hypothesis was that ephedrine reduces onset time compared to placebo (saline).

We included patients aged ≥ 80 years with American Society of Anesthesiologists physical health Classes I-III scheduled for surgery under total intravenous anaesthesia with rocuronium. Patients were randomised to administration of ephedrine 0.15 mg kg^-1 or saline (placebo) before administration of rocuronium 0.6 mg kg^-1. Primary outcome was time to Train-of-Four (TOF) count 0 measured from the end of administration of rocuronium. Secondary outcomes included intubating conditions, occurrence of new cardiac arrhythmia, change in mean arterial blood pressure (MAP) and occurrence of hoarseness and sore throat at 24 and 72 h after surgery.

Forty-four patients were allocated to receive ephedrine and 43 patients to receive saline, but the primary endpoint could only be analysed in 38 and 37, respectively. Time to TOF 0 was 134 s (IQR, 107 to 180) in the ephedrine group compared to 139 s (IQR, 121 to 185) in the placebo group (p = 0.60), difference 9 s (95% CI, -14 to 31). Change in MAP was 4 mmHg (SD 21) in the ephedrine group compared to -6 mmHg (SD 22) in the placebo group (p = 0.03), difference 10 mmHg (95% CI 1 to 20). Cardiac arrythmias occurred more often in the ephedrine group compared to the placebo group (p < 0.001). No difference was found in intubating conditions or occurrence of hoarseness or sore throat after surgery.

No reduction was found in onset time of rocuronium 0.6 mg kg^-1 in elderly patients after administration of ephedrine 0.15 mg kg^-1 compared to placebo during induction of anaesthesia. The ephedrine group had more stable blood pressure, but a larger occurrence of tachycardia compared to placebo.

Ephedrine intravenous treatment, which can be given around the time of anesthesia induction and muscle relaxant administration, is thought to shorten rocuronium effect onset time for some patients. In this study, this was tested in an elderly cohort, in a blinded trial compared to a placebo treatment. Ephedrine was noted to have predictable cardiovascular effects, but did not have an effect on rocuronium onset time in this cohort.

NCT06681662.