Davide Bracco

Volatile anaesthetics have gained more popularity recently due to the potential for cardiac protection. Ultra-fast-track anaesthesia implies the immediate extubation after cardiac surgery. The purpose of this prospective randomized double-blind controlled study is to compare the cardioprotective effects of sevoflurane and isoflurane in off-pump cardiac bypass surgery. Forty patients undergoing elective off-pump cardiac bypass surgery with high thoracic epidural analgesia and immediate extubation at the end of surgery were randomized into two groups. During surgery, anaesthesia was provided with either 1 minimum alvelolar anaesthetic concentration of sevoflurane or 1 minimum alvelolar anaesthetic concentration of isoflurane. Troponin-T, creatine kinase-MB, left ventricular wall motion anomalies, time to extubation, respiratory functions and haemodynamic parameters were compared between the two groups by analysis of variance. All patients were successfully extubated in the operating theatre with minimal postoperative pain. Serial creatine kinase-MB and troponin-T concentrations were not significantly different between the two volatile agents. Haemodynamic stability throughout surgery and contractility was not different between groups. However, extubation time was significantly shorter with sevoflurane (10 +/- 5 min) compared to isoflurane (18 +/- 4 min). This study indicates that during off-pump cardiac bypass surgery, sevoflurane and isoflurane provide the same ischaemic cardioprotective effects. There is no difference for heart contractility and haemodynamic values during and after off-pump cardiac bypass surgery between the two agents. Sevoflurane allows a more rapid recovery from anaesthesia, but this does not translate into better pulmonary function or haemodynamics. Both agents are similar in ultra-fast-track off-pump cardiac bypass surgery.

This study was performed on patients after coronary artery bypass surgery, and in healthy volunteers to assess discrepant oxygen consumption (VO2) measurement between indirect calorimetry and Fick methods. Further evaluations were performed to point out the technical failure. In this prospective study, the VO2 was assessed in the patients using a commercial indirect calorimeter and the reverse Fick method. This calorimeter does not directly measure gas flow, but it assumes a constant preset flow. Bench testing of the calorimeter was performed in spontaneous and respirator mode using a reference calorimeter in healthy volunteers. An important overestimation of VO2 and carbon dioxide production (VCO2) of approximately 30% was found in both groups. The actual flow was lower than the preprogrammed value. This lead to spuriously high fractions of carbon dioxide and low fraction of oxygen. VCO2 and VO2, calculated with the overestimated gas flow value were overestimated, while respiratory quotient remained unchanged. Technical check-up revealed leaks in the mixing chamber and in the sampling lines. Indirect calorimetry is a useful clinical tool, but the investigator has to be very attentive to all potentially interfering factors and hazards.

Fungal infections are increasingly common in burn patients. We performed this study to determine the incidence and outcomes of fungal cultures in acutely burned patients. Members of the American Burn Association's Multicenter Trials Group were asked to review patients admitted during 2002-2003 who developed one or more cultures positive for fungal organisms. Data on demographics, site(s), species and number of cultures, and presence of risk factors for fungal infections were collected. Patients were categorized as untreated (including prophylactic topical antifungals therapy), nonsystemic treatment (nonprophylactic topical antifungal therapy, surgery, removal of foreign bodies), or systemic treatment (enteral or parenteral therapy). Fifteen institutions reviewed 6918 patients, of whom 435 (6.3%) had positive fungal cultures. These patients had mean age of 33.2 +/- 23.6 years, burn size of 34.8 +/- 22.7%TBSA, and 38% had inhalation injuries. Organisms included Candida species (371 patients; 85%), yeast non-Candida (93 patients, 21%), Aspergillus (60 patients, 14%), other mold (39 patients, 9.0%), and others (6 patients, 1.4%). Systemically treated patients were older, had larger burns, more inhalation injuries, more risk factors, a higher incidence of multiple positive cultures, and significantly increased mortality (21.2%), compared with nonsystemic (mortality 5.0%) or untreated patients (mortality 7.8%). In multivariate analysis, increasing age and burn size, number of culture sites, and cultures positive for Aspergillus or other mold correlated with mortality. Positive fungal cultures occur frequently in patients with large burns. The low mortality for untreated patients suggests that appropriate clinical judgment was used in most treatment decisions. Nonetheless, indications for treatment of fungal isolates in burn patients remain unclear, and should be developed.