Compared effects on cerebral oxygenation of ephedrine vs phenylephrine to treat hypotension during carotid endarterectomy.

While both ephedrine and phenylephrine are currently used to treat hypotension occurring during carotid endarterectomy (CEA) under general anaesthesia, phenylephrine may have deleterious effects on the cerebral watershed, due to its exclusively vasoconstrictive action. In this controlled, double-blind randomised trial, we compared the effects of ephedrine and phenylephrine administered in a standardised algorithm to treat the first hypotensive event occurring since induction of anaesthesia until carotid cross-clamping. The algorithm consisted of 1-to-3 boluses of 6 mg of ephedrine or 50 µg of phenylephrine, after a goal-directed fluid therapy. In case of failure, the treatment switched to the other study drug. Cerebral tissue oxygen saturation (SctO2 ) was monitored by near infrared spectroscopy (NIRS), and the primary outcome was the restoring effect of SctO2 (ipsilateral to surgery) to baseline values. Secondary postoperative outcomes were: contralateral SctO2 , neurological outcomes, and plasma S100B protein measured at discharge from post-anaesthesia care unit. Ephedrine treatment provided a higher rate of restoration of ipsilateral SctO2 than phenylephrine (93.2% vs 85.1%, P=.034); this was also noted for contralateral SctO2 (93.5% vs 90.7%, P=.026). The gain in SctO2 on the lowest value during hypotension was also higher under ephedrine than phenylephrine (6.4% vs 4.3% ipsilateral, 5.1% vs 4% contralateral), but not significantly so. Clinical outcomes were unaffected by the treatment, but S100B protein plasma concentration was higher in the phenylephrine group. To conclude, this pilot trial, focusing on intermediate outcomes, suggests that ephedrine should be preferred to phenylephrine to treat hypotension during CEA.

Pupil diameter during postanesthetic recovery is not influenced by postoperative pain, but by the intraoperative opioid treatment.

STUDY OBJECTIVE: To investigate whether pupil diameter (PD) measured during scotopic conditions is influenced by pain in conscious patients in the early postoperative period. DESIGN: Prospective, observational, cohort study. SETTING: Single-center, postanesthesia care unit (PACU). PATIENTS: Patients scheduled for a surgery during general anesthesia. INTERVENTIONS: Baseline PD was measured the day before surgery. Patients were observed on admission to the PACU, immediately after extubation, during the different steps of analgesic intervention (demand, relief, plus intermediate measures when relevant), and either at discharge or 3 hours after admission. MEASUREMENTS: PD, pain (numerical rating scale), and alertness (Observer's Assessment of Alertness/Sedation scale). MAIN RESULTS: Of 103 patients enrolled, 80 required analgesia in the PACU and completed follow-up. Pain intensity evolved in line with expectations (temporary increase then relief), and alertness increased with time. PD increased from low mean values at admission to the PACU (40% of baseline) to a plateau throughout the rest of the study period (80% of baseline) and was not related to pain intensity. Multivariate analyses suggested that the factors influencing PD (or its value related to baseline) were time since extubation and the type of opioid (remifentanil, sufentanil, or sufentanil at high doses) administered during surgery. CONCLUSIONS: Because of a residual effect of intraoperative opioids and a level of nociceptive stimulation lower than in surgical conditions, PD is not significantly influenced by early postoperative pain or pain relief.