Anaesthesia
-
Caesarean section carries a high risk of awareness, especially in the period prior to neonatal delivery. We investigated the concentration of sevoflurane required to maintain bispectral index (BIS) < 60 until delivery occurred. We enrolled 23 parturients into an up-down sequential allocation study. ⋯ The EC(50) for sevoflurane was 1.22% (1.08-1.33, 95% CI). The probability of maintaining BIS < 60 was < 55% at a concentration of < 1.1%; this increased to 80% at concentrations of 1.2-1.3%. We conclude that sevoflurane concentrations of at least 1.2-1.3% should be administered in uncomplicated Caesarean section, so as to minimise the risk of awareness and recall.
-
Peri-operative myocardial ischaemia is the single most important risk factor for an adverse cardiac outcome after non-cardiac surgery. The present study examines whether intermittent 12-lead ECG recordings can be used as an early warning tool to identify patients suffering from peri-operative myocardial ischaemia and subsequent myocardial cell damage. Fifty-five vascular surgery patients at risk for or with a history of coronary artery disease were monitored for peri-operative myocardial ischaemia using intermittent 12-lead ECG recordings taken pre-operatively and at 15 min, 20 h, 48 h, 72 h and 84 h postoperatively. ⋯ The concordance of mass concentration of creatine kinase myocardial band with 12-lead ECG recordings was 75%, and the corresponding value for Holter monitoring was 68%. The concordance of cardiac troponin T and I levels with the 12-lead method was 85% and 87%, respectively, and concordance with Holter monitoring was 72% and 66%, respectively. The postoperative 12-lead ECG identified peri-operative myocardial ischaemia associated with subsequent myocardial cell damage in most patients undergoing vascular surgery.
-
Alterations of electrolytes and albumin cause metabolic acid-base disorders. It is unclear, however, to what degree these plasma components affect the overall metabolic acid-base state in the course of critical illness. We performed serial analyses of the metabolic acid-base state in 30 critically ill patients over the course of 1 week. ⋯ Changes in serum chloride and unmeasured anions were responsible for changes of 41% and 22% in the metabolic acid-base state, respectively. Sodium and albumin played a minor role. In conclusion, chloride is the major determinant of metabolic acid-base state in critical illness.
-
Infusion devices for continuous and precise drug administration are indispensable tools in anaesthesia and critical care medicine. Problems such as start-up delays, non-continuous flow and susceptibility to hydrostatic pressure changes at low infusion rates resulting in accidental bolus release or prolonged flow interruption are inherent to current infusion technology. ⋯ The performance of the MVIP prototype has been evaluated and compared with standard syringe infusion pump assemblies. The novel MVIP concept has thereby proven to eliminate most problems during infusion start-up, steady state flow and vertical pump displacement, and has the potential of revolutionising infusion technology and setting a new dimension in patient safety.