Specific aims: is randomized trial will assess the impact of hypotensive versus normotensive anesthesia on cognitive, cardiac and renal complications in an elderly population undergoing total hip replacement. Secondly, this trial will document and comprehensively assess the incidence of persistent, post-operative josses in cognitive function in an elderly population undergoing elective non-cardiac surgery. Thirdly, this trial will assess the impact of deliberate hypotensive anesthesia on intraoperative blood loss and the need for non-autologous transfusions in this population. Experimental design and methods: A prospective randomized trial in elderly patients with comorbid medical conditions undergoing elective total hip replacement assessing the effect of hypotensive vs normotensive anesthesia on the outcomes of cardiac, renal and cognitive complications. Baseline clinical and demographic data and comprehensive intra-operative monitoring data will be collected and analyzed. Occurrence of persistent deterioration of performance will be assessed in three cognitive domains of linguistic, psychomotor/attention, and memory function. Outcome will be measured by intrasubject comparison of psychometric test results three months post-operatively versus pre-operatively. Occurrence of major cardiac and renal complications will be evaluated using a sensitive surveillance protocol to detect perioperative myocardial infarction, pulmonary edema, pulmonary emboli, congestive heart failure, and renal injury. The administrator of the cognitive tests, the co-investigators assessing and reviewing post-operative cardiac outcomes, and the coinvestigators reviewing and analyzing the cognitive test results will be blinded to the type of anesthesia intervention. Functional impact will be assessed with an evaluative scale administered pre-operatively and three months post-operatively. The results of the functional scale will be correlated with the results of serial psychometric testing to provide a context in which changes on psychometric tests can be interpreted. Long term objective: The long term objective is to assess the risks and benefits of hypotensive anesthesia in elderly patients undergoing elective surgery.
