Comments regarding ‘The Role of Cerebral Oximetry in Combination with Awake Testing in Patients Undergoing Carotid Endarterectomy under Local Anaesthesia’

Abstract

The search for a reliable method of identifying patients requiring a shunt during CEA under general anaesthesia (GA) has been the Holy Grail of vascular surgeons ever since it became a routine part of clinical practice. Although many authors tried to apply criteria for shunt insertion under GA data derived during LA CEA by McCleary et al clearly showed that this concept was unreliable with cerebral autoregulation being preserved during LA surgery (spontaneous rise in systemic BP and cerebral oxygenation following carotid clamping) but lost during GA CEA. This explains the high frequency with which anaesthetists increased blood pressure pharmacologically in GA patients in the GALA Trial, perhaps masking the benefit of LA CEA. It also clarified why physiological measurements during LA CEA cannot be extrapolated toGApatients. Nevertheless the current study suggests that routine measurements of rSO2 might meet these aims. Mcleary’s findings suggest that the evidence presented in this paper may be physiologically flawed. Further concern about the validity of the study is raised by the authors’ comment that the cut-off for rSO2might vary depending upon the type of equipment used, the explanation that they have given for earlier studies failing to show similar findings. This is a critical limitation particularly if the rSO2 measurements for