Comparison of lactate or BE during out-of-hospital cardiac arrest to determine metabolic acidosis.

During cardiopulmonary resuscitation, pH and base excess (BE) decrease to a variable degree due to metabolic acidosis. The main cause has been shown to be lactate, which cannot be eliminated sufficiently because of low perfusion during cardiac massage. Both BE and lactate can be measured in the prehospital phase. The aim of the study was to determine if BE and lactate are comparable variables during cardiopulmonary resuscitation (CPR) and if the measurement of lactate level alone would be sufficient to determine the patient's metabolic status and sufficiently reliable to determine the administration of buffer solutions. During the observation period, we registered 31 patients (21 males, ten females) who were resuscitated according to European Resuscitation Council recommendations, who had blood gas analysis and lactate levels measured in blood taken by arterial puncture or arterial line. The first measurement from each patient was taken after primary resuscitation (within 5-20 min). The mean lactate level was 9.85+/-2.98 (range, 4.1-18.7) mmol/l, and the mean BE was -15.0+/-5.98 (range, 5.5 to -24.3). There were statistically significant correlations between the lactate level and BE and pH (linear correlation, r=-0.673, P<0,001 and r=-0,683, P<0,001, respectively), but not with pO2 and pCO2. The receiver-operated curve analysis showed that a cut-off point of 7.0 mmol/l lactate indicates a BE below -10 with a sensitivity of 96% and a specificity of 67%. Lactate measurement is a valuable tool to determine metabolic acidosis during CPR and may be able to replace blood gas analysis in this situation.

Can ASA grade or Goldman's cardiac risk index predict peri-operative mortality? A study of 16,227 patients.

This trial was designed to study the correlation between peri-operative mortality in patients undergoing elective surgery and the physical status classification of the American Society of Anesthesiologists, the Goldman multifactorial cardiac risk index or the two indices combined. All patients scheduled for elective surgery over a 5-year period were evaluated pre-operatively and were scored according to both indices. Of 16,227 patients studied, 215 died within 4 weeks of operation. Both indices correlated significantly with peri-operative mortality, the ASA grade showing a closer correlation. A regression tree analysis divided the combination groups into five subgroups where the mortality was lowest (0.4%) in ASA grade < or = 2 and cardiac risk index group I (score 0-5 points) and increased up to 7.3% in ASA grade = 4 and cardiac risk index group > or = 3 (score > 13 points). We conclude that for this large number of patients peri-operative mortality can be predicted with the ASA grade and, to a lesser degree, with the cardiac risk index. Applied in the correct way, the combination of the two scores can increase the accuracy of prediction of peri-operative mortality.