Incidence of akathisia after postoperative nausea and vomiting prophylaxis with droperidol and ondansetron in outpatient surgery: A multicentre controlled randomised trial.

BACKGROUND: Akathisia, a distressing movement disorder induced by butyrophenones, has been described with low doses of droperidol used for postoperative nausea and vomiting (PONV) prophylaxis, but the incidence remains unclear. OBJECTIVES: To determine the incidence of akathisia after PONV prophylaxis with two doses of droperidol in comparison with ondansetron, in patients undergoing ambulatory surgery. We hypothesised that the incidence of akathisia is higher with droperidol than that with ondansetron. DESIGN: Randomised controlled double blind trial. SETTING: Two University Hospital Centres and two private Clinics from January to September 2014. PATIENTS: Patients (n=297) undergoing general anaesthesia for ambulatory surgery were randomly allocated to receive PONV prophylaxis with droperidol (0.625 or 1.25 mg) or ondansetron 4 mg; patients of the three groups also received 4 mg of dexamethasone. Exclusion criteria were contraindication to droperidol and ondansetron, use of psychotropic medications or benzodiazepines or history of psychotic illness. INTERVENTIONS: Participants received droperidol (0.625 or 1.25 mg) or ondansetron 4 mg during general anaesthesia. After discharge from the postanaesthesia care unit presence and severity of akathisia were assessed using the Barnes Akathisia Rating Scale at 4 h postoperatively. MAIN OUTCOME MEASURES: Score of the Global Clinical Assessment of Akathisia of Barnes Akathisia Rating Scale. RESULTS: The number of akathisia observed was 1/118 (0.8%) in the ondansetron group, 1/84 (1.2%) in droperidol 0.625 mg group, and 3/87 (3.4%) in droperidol 1.25 mg group. The akathisia rate difference among the three groups was not significant (P = 0.52). We could not demonstrate significant differences in the incidence of akathisia between the two doses of droperidol. The only case of marked akathisia treated with benzodiazepines was observed after droperidol 1.25 mg. CONCLUSION: The use of droperidol or ondansetron for PONV prophylaxis is associated to a low incidence of akathisia (0.8 to 3.4%) after general anaesthesia for ambulatory surgery. TRIAL REGISTRATION: Clinicaltrials.gov: NCT01942343.

Apparent Km of mitochondria for oxygen computed from Vmax measured in permeabilized muscle fibers is lower in water enriched in oxygen by electrolysis than injection.

BACKGROUND: It has been suggested that oxygen (O2) diffusion could be favored in water enriched in O2 by a new electrolytic process because of O2 trapping in water superstructures (clathrates), which could reduce the local pressure/content relationships for O2 and facilitate O2 diffusion along PO2 gradients. MATERIALS AND METHODS: Mitochondrial respiration was compared in situ in saponin-skinned fibers isolated from the soleus muscles of Wistar rats, in solution enriched in O2 by injection or the electrolytic process 1) at an O2 concentration decreasing from 240 µmol/L to 10 µmol/L (132 mmHg to 5 mmHg), with glutamate-malate or N, N, N', N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD)-ascorbate (with antimycin A) as substrates; and 2) at increasing adenosine diphosphate (ADP) concentration with glutamate-malate as substrate. RESULTS: As expected, maximal respiration decreased with O2 concentration and, when compared to glutamate-malate, the apparent Km O2 of mitochondria for O2 was significantly lower with TMPD-ascorbate with both waters. However, when compared to the water enriched in O2 by injection, the Km O2 was significantly lower with both electron donors in water enriched in O2 by electrolysis. This was not associated with any increase in the sensitivity of mitochondria to ADP; no significant difference was observed for the Km ADP between the two waters. CONCLUSION: In this experiment, a higher affinity of the mitochondria for O2 was observed in water enriched in O2 by electrolysis than by injection. This observation is consistent with the hypothesis that O2 diffusion can be facilitated in water enriched in O2 by the electrolytic process.