Cerebral oximetry to reduce perioperative morbidity.

The use of cerebral oximetry to guide intraoperative management has been shown to improve patient outcomes in cardiac surgery. This pilot trial assessed the feasibility of performing a similar study of outcome in patients over the age of 70 years undergoing non-cardiac surgery. Patients over the age of 70 years undergoing total knee or hip arthroplasty or bowel resection surgery were randomly assigned to have cerebral oximetry values monitored (intervention group) or not monitored (control) while under general anaesthesia. Indicators of proof of concept were: rate of complications, rate of cerebral desaturation, relationship between cerebral desaturation and complications, and anaesthetist response to cerebral desaturation. Forty patients were recruited and randomised to a control group (n=20) or an intervention group (n=20). The proportion of the study population who had a complication was 40% (95% confidence interval [CI] 26% to 55%). Cerebral desaturation (<75% of baseline) occurred in only two patients (5.0% (CI 1.4% to 16%)), one in each group, and neither of those patients recorded a complication. Changes to anaesthetic management on the basis of cerebral oximetry values occurred in only two patients in the intervention group (10% (CI 2.8% to 30%)). Maintenance of cerebral oximetry values appeared to be closer to baseline in the intervention group than in the control group but this difference was not significant (P=0.15). Our results indicated that complications occurred frequently in the study population but did not appear to be associated with cerebral desaturation events. These findings do not support a larger intervention study using the current study population.

Pacemaker-driven tachycardia induced by electrocardiograph monitoring in the recovery room.

Monitoring devices are known to induce tachycardia in minute-ventilation rate-responsive pacemakers. This is because some monitoring devices measure the same parameter as do the pacemakers (change in thoracic impedance). Hence, the biological signal to the pacemaker is increased and is misconstrued as increased minute ventilation causing tachycardia which resolves when the monitoring device is removed. Whilst this could occur for all minute-volume rate responsive pacemakers, most reported interactions have been with the Telectronics META series. We present a case of an interaction between a Telectronics Tempo DR pacemaker (St. Jude Medical) and an Agilent Patient Care System (Philips). Failure to recognise the true nature and cause of such tachycardias may lead to mismanagement of the patient, including the inappropriate use of cardio-active medications.

Knowledge of cardiopulmonary resuscitation protocols and level of anaesthetic training.

Inadequate recall of resuscitation protocols has contributed to poor performance of resuscitation in simulation studies. We asked, does the level of anaesthesia training affect knowledge of cardiopulmonary resuscitation protocols? We used a questionnaire that covered the areas of basic life support, advanced adult life support and paediatric life support. The proportions of correct answers were hospital medical officers 50%, junior registrars 62%, senior registrars 84% and consultants 42%. The consultant group performed worse than all other groups for the basic life support and advanced life support questions. We suggest yearly resuscitation training for all anaesthetists and anaesthesia trainees.