Minimum Alveolar Concentration of Sevoflurane as a Single Hypnotic Agent to Maintain BIS Below 50 in Patients During Normothermic Cardiopulmonary Bypass

OBJECTIVES: Minimum alveolar concentration (MAC) of volatile anesthetic agents to maintain bispectral index (BIS) below 50 in 50% of patients was defined as MACBIS50. The primary objective of this study was to determine the minimum alveolar concentration of sevoflurane as a single hypnotic agent to maintain BIS below 50 in patients during normothermic cardiopulmonary bypass. DESIGN: Prospective and observational study. SETTING: Dante Pazzanese Institute of Cardiology, Brazil. PARTICIPANTS: Eighteen consecutive patients scheduled for elective coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) under general anesthesia, American Society of Anesthesiologists physical status classes III and IV, between the ages of 40 and 70, were included in the study. METHODS: All patients underwent inhalation induction with facial mask using sevoflurane (Cristália) in 100% oxygen, pancuronium (Cristália) 0.1 mg/kg, and sufentanil (Cristália) 0.5 µg/kg intravenously (IV) administered. A single bolus dose of sufentanil, 1.0 µg/kg IV, was administered before surgical incision. MACBIS50 was calculated using the midpoint concentration of patients involving a crossover (BIS < or ≥50) according to Dixon's Up-and-Down method. The Up-and-Down sequence also was analyzed by probit test that enabled the authors to obtain the effective dose 50 (ED50) and effective dose 95 (ED95) of sevoflurane to maintain a BIS value <50, with a 95% confidence interval (95% CI) of the mean. RESULTS: A total of 15 patients were analyzed in this study. MACBIS50 of sevoflurane as a single hypnotic agent was 0.82% (95% CI 0.47-1.16) in patients aged 40 to 70 undergoing CABG during normothermic CPB. The ED50 and ED95 of sevoflurane to maintain a BIS value <50 for the same context were 0.73% (95% CI 0.45-1.00) and 1.39 (95% CI 0.42-2.37) by means of probit analysis, respectively. CONCLUSION: MACBIS50 of sevoflurane as a single hypnotic agent was 0.82% in patients undergoing CABG during normothermic CPB.

Use of lyophilized fibrinogenconcentrate in cardiac surgery: a systematic review

Use of fibrinogen concentrate among cardiac anesthetists is growing especially for the benefitsrelated to the reduction in the administration of bleeding and allogeneic blood components, which are exacerbatedby cardiopulmonary bypass. Moreover, these products underwent complete viral inactivation, reducingthe risks of contamination associated with transfusion. The purpose of this research was to review the literaturelooking for randomized controlled trials regarding fibrinogen concentrate and its benefits in cardiac surgery.Method: The papers used in this review were searched in BioMed Central, PubMed, Embase, and the CochraneCentral Register of Clinical Trial by two investigators. The full search strategy was performed to identify allrandomized controlled trials in the last 10 years, comparing the use of fibrinogen in the adult treatment of perioperativebleeding to standard treatment or placebo.Results: Only four articles matching the selection criteria for final analysis were identified and only 79 patientsreceived therapy with fibrinogen concentrate in randomized trials performed in cardiac surgery.Conclusions: During the last 10 years, few randomized controlled trials were performed to confirm the realbenefit of using lyophilized fibrinogen to reduce bleeding in cardiac surgery. However, when indicated, it may bea good option in order to reduce the consumption of blood products in the treatment of perioperative bleeding,following an algorithm based on point-of-care testing.