Effects of Two Target-controlled Concentrations (1 and 3 ng/ml) of Remifentanil on MACBARof Sevoflurane

Background The aim of this prospective, randomized, double-blind study was to determine the effects of two different target-controlled concentrations of remifentanil (1 and 3 ng/ml) on the sevoflurane requirement for blunting sympathetic responses after surgical incision (MACBAR). Methods Seventy-four patients aged 20-50 yr, with American Society of Anesthesiologists physical status I, were anesthetized with propofol, cisatracurium, and sevoflurane with a mixture of 60% nitrous oxide in oxygen. Then, patients were randomly allocated to receive no remifentanil infusion (n = 27) or a target-controlled plasma concentration of 1 ng/ml (n = 27) or 3 ng/ml remifentanil (n = 20). Sympathetic responses to surgical incision (presence or absence of an increase in either heart rate or mean arterial blood pressure of 15% or more above the mean of the values measured during the 2 min before skin incision) were determined after a 20-min period of stable end-tidal sevoflurane and target-controlled remifentanil concentrations. Predetermined end-tidal sevoflurane concentrations and the MACBAR for each group were determined using an up-and-down sequential-allocation technique. Results The MACBAR of sevoflurane was higher in the group receiving no remifentanil (2.8% [95% confidence interval: 2.5-3.0%]) as compared with patients of the groups receiving 1 ng/ml (1.1% [0.9-1.3%]; P = 0.012) and 3 ng/ml remifentanil (0.2% [0.1-0.3%]; P = 0.006). When considering a minimum anesthetic concentration (MAC) value in this age population and the contribution of 60% nitrous oxide (0.55 MAC), the combined MACBAR values, expressed as multiples of the MAC, were 1.95 MAC, 1.1 MAC, and 0.68 MAC, in the three groups, respectively. Conclusion A target-controlled concentration of 1 ng/ml remifentanil results in a 60% decrease in the MACBAR of sevoflurane combined with 60% nitrous oxide. Increasing the target concentration of remifentanil to 3 ng/ml produces a further 30% decrease in the MACBAR values of sevoflurane

Sevoflurane vs propofol in high risk cardiac surgery: design of the randomized trial “Sevo-Aifa”

Objective. Recent evidence indicates that volatile anesthetics improve post-ischemic recovery. In a meta-analysis of 22 randomized studies, the use of volatile anesthetics was associated with significant reduction in myocardial infarction and mortality. All the studies in this meta-analysis included low risk patients undergoing isolated procedures (mostly isolated coronary artery bypass grafting). We want to confirm the cardioprotective effects of volatile anesthetics, in cardiac surgery, as indicated by a reduced intensive care unit stay and/or death in a high risk population of patients, undergoing combined valvular and coronary procedures. Methods. Four centres will randomize 200 patients to receive either total intravenous anesthesia with propofol or anesthesia with sevoflurane. All patients will receive a standard average dose of opiates. Perioperative management will be otherwise identical and standardized. Transfer out of the intensive care unit will follow standard criteria. Results. Reduced cardiac damage will probably translate into better tissue perfusion and faster recovery, as documented by a reduced intensive care unit stay. The study is powered to detect a reduction in the composite end point of prolonged intensive care unit stay (>2days) and/or death from 60% to 40%. Conclusions. This will be the first multicentre randomized controlled trial comparing the effects of volatile anesthetics and total intravenous anesthesia in high risk patients undergoing cardiac procedures. Our trial should help clarify whether or not volatile agents should be recommended in high risk patients undergoing cardiac surgery

Perioperative fenoldopam for the prevention of acute renal failure in non-cardiac surgery, randomized clinical trial

Purpose. Acute renal failure is a serious complication of surgery causing morbidity and mortality. The aim of this study was to evaluate the efficacy of fenoldopam, a selective dopamine-1 receptor agonist, in patients at high risk of perioperative renal dysfunction. Methods. In this prospective single-center randomized double-blind trial we enrolled 64 patients undergoing major surgery. Patients received either fenoldopam at a dosage of 0.05 mcg/kg/min or dopamine at a dosage of 2.5 mcg/kg/min after anesthesia induction for a 12-hour period. The primary endpoint was defined as 25% serum creatinine increase from baseline after surgery. Results. All the patients included were at high risk of perioperative renal dysfunction and underwent major surgery. The two groups (fenoldopam versus dopamine) were homogenous cohorts and no difference in outcome was observed. The incidence of acute renal failure was similar: 11/32 (34%) in the fenoldopam group and 14/32 (44%) in the dopamine group (p=0.6). The postoperative serum creatinine peak was also similar in the two groups. No in-hospital death was observed. Conclusion. Despite an increasing number of reports suggesting renal protective properties of fenoldopam, we observed no difference in clinical outcome compared to dopamine in a high-risk population undergoing major surgery