Influence of preoperative oral rehydration on arterial plasma rocuronium concentrations and neuromuscular blocking effects: A randomised controlled trial.

BACKGROUND: The influence of preoperative rehydration on the action of rocuronium has not yet been investigated. OBJECTIVE: The objective is to evaluate the hypothesis that preoperative rehydration lowers arterial rocuronium plasma concentrations and changes its associated neuromuscular blocking effects during induction of anaesthesia. DESIGN: Randomised, single-blinded study. SETTING: A secondary hospital from October 2013 to July 2014. PATIENTS: In total, 46 men undergoing elective surgery were eligible to participate and were randomly allocated into two groups. Exclusion criteria were severe hepatic, renal or cardiovascular disorder; neuromuscular disease; history of allergy to rocuronium; BMI more than 30 kg m; receiving medication known to influence neuromuscular function. INTERVENTION: Participants received 1500 ml of oral rehydration solution (rehydration group) or none (control group) until 2 hours before anaesthesia. Arterial blood samples were obtained 60, 90 and 120 s and 30 min after rocuronium (0.6 mg kg) administration during total intravenous anaesthesia. Responses to 0.1-Hz twitch stimuli were measured at the adductor pollicis muscle using acceleromyography. MAIN OUTCOME MEASURES: Arterial plasma rocuronium concentrations. RESULTS: Arterial plasma rocuronium concentrations at 60, 90 and 120 s in the rehydration and control groups were 9.9 and 13.7, 6.8 and 9.5 and 6.2 and 8.1 µg ml, respectively (P = 0.02, 0.003 and 0.02, respectively); the onset times in the rehydration and control groups were 92.0 and 69.5 s (P = 0.01), and the times to twitch re-appearance were 25.3 and 30.4 min (P = 0.004), respectively. CONCLUSION: Preoperative rehydration significantly reduces arterial plasma rocuronium concentrations in the first 2 minutes after administration, prolonging the onset time and shortening the duration of effect. A higher dose or earlier administration should be considered for patients who receive preoperative rehydration. TRIAL REGISTRATION: Umin identifier: UMIN000011981.

[The Effect of Preoperative Oral Rehydration on Hemodynamic Changes during Induction of Anesthesia and Intraoperative Fluid Management].

BACKGROUND: Preoperative oral rehydration solution (ORS) prevents dehydration before surgery. Therefore taking enough ORS possibly reduces the hemodynamic changes during induction of anesthesia, and reduces the amount of fluid needed during anesthesia. METHODS: Forty patients undergoing elective surgery were randomly assigned to two groups: drinking 1,500 ml ORS 6 to 2 hours before anesthesia (ORS group) and nothing by mouth from 6 hours before anesthesia (Control group). Anesthesia induction was performed using propofol and remifentanil. To evaluate the hemodynamic changes, hemodynamic parameters including heart rate, blood pressure, cardiac index (CI), and stroke volume variation (SVV) were recorded before induction, after propofol administration, and after remifentanil administration. Total urine volume and the amount of fluid were also recorded at the end of the anesthesia. RESULTS: In ORS group, CI showed a significantly higher value after propofol administration (P = 0.046). SVV was significantly lower (P < 0.0001) and total amount of fluid during anesthesia was significantly reduced (P < 0.0001) in ORS group. CONCLUSIONS: Preoperative oral rehydration increases circulating blood volume, it keeps high CI during induction of anesthesia, and reduces the amount of intraoperative fluid.

[Effect of Preoperative Oral Rehydration on Onset Time and Recovery Time of Rocuronium].

BACKGROUND: Preoperative oral rehydration solution (ORS) prevents hypovolemia. The aim of this study was to compare the effect of intubating dose of rocuronium in patients taking and those not taking preoperative ORS. METHODS: Twenty patients, ASA I aged 20-50 years scheduled for elective surgery, were investigated and randomly assigned to two groups: drinking 1,500 ml ORS 6 to 2 hours before anesthesia (ORS group) and nothing by mouth from 6 hours before anesthesia (control group). Anesthesia was maintained with propofol and remifentanil, and rocuronium 0.6 mg x kg(-1) was administrated. To evaluate the effect of rocuronium, acceleromyography at the adductor pollicis was performed using 0.1 Hz stimulation. Cardiac index (CI) and stroke volume variation (SVV) from FloTra/Vigileo, times to 95% twitch depression as onset time (OT), and times to first twitch re-detection (TR) were recorded. RESULTS: SVV was significantly lower in ORS group (P = 0.03), and CI showed no difference. In ORS group, TR was significantly shorter than that of control group (P=0.002), and OT tended to be prolonged (99.0 ± 36.3 s vs. 84.0 ± 37.5 s), but not significantly. CONCLUSIONS: Preoperative oral rehydration possibly increases circulating blood volume, and shortens the duration of rocuronium effect.