Perioperative Control of Cerebral Blood flow in Carotid Endarterectomy.
We are studying the effect of carotid endarterectomy on cerebral auto-regulation. Our findings suggest there is not an immediate improvement in cerebral autoregulation following surgery and that there may be a place for continuous cerebral blood flow monitoring in patients with postoperative cardiovascular instability. Reduced cerebrovascular vasodilatory reserve, whilst an important predictor of stroke in the non surgical setting, does not appear to predispose to post-operative cerebral hyper-perfusion.
Cardiopulmonary Exercise Testing and Perioperative Cardiovascular Risk
Major vascular surgery is associated with a risk of perioperative myocardial infarction and death of between 5 and 10%. There is an association between a limited cardio-respiratory reserve measured on exercise testing and perioperative cardiovascular complications. We are currently examining the association between anaerobic threshold, the stress response to surgery and quality of life after surgery. This work will lead to a clearer understanding of the mechanisms underlying perioperative complications delaying recovery and facilitate the development of strategies to enhance recovery.
Ischaemia Reperfusion Injury and Perioperative Renal Impairment
There is evidence that perioperative renal injury can be attenuated by steroids. We have completed studies of the use of steroids in patients undergoing liver transplantation and are undertaking a study in patients undergoing aortic surgery. Our findings suggest that steroids may offer some protection in hepatic surgery, although this is of a lesser magnitude than that found in cardiac surgery.
Figure 1. A cardiopulmonary exercise test in progress
Elliot SC, Paramasivam K, Bodenham AR, Howell SJ, Mallick A. Pumpless extracorporeal carbon dioxide removal for life threatening asthma. Critical Care Medicine 2007; 35: 945-8.
Brown LC, Greenhalgh RM, Howell S, Powell JT, Thompson SG. Patient fitness and survival following abdominal aortic aneurysm repair: results from the UK EVAR trials. British Journal of Surgery 2007; 94:709-16
Howell SJ, Vohra RS. Perioperative management of patients undergoing non-cardiac vascular surgery. European Journal of Vascular and Endovascular Surgery 2007; 34:625-31.