Cardiac troponin I: its contribution to the diagnosis of perioperative myocardial infarction and various complications of cardiac surgery.

OBJECTIVE: To study the value of assaying cardiac troponin I (cTnI) for the early diagnosis of perioperative myocardial infarction (PMI) and various complications of cardiac surgery. DESIGN: A prospective observational clinical study. SETTING: Biochemical laboratory, anesthesia, and cardiac surgery department of Hôpital Broussais. PATIENTS: Two hundred and sixty consecutive patients undergoing cardiac surgery. INTERVENTIONS: All patients underwent coronary artery bypass grafting and/or valvular surgery under extracorporeal circulation. Per-operative and postoperative follow-up consisted of electrocardiogram, echocardiography (mainly by the transesophageal approach), and serial determinations of biochemical markers such as creatinine kinase-MB isoenzyme (CK-MB) and cTnI. PMI, new ST segment changes, and ventricular arrhythmias were considered postoperative adverse cardiac outcome. MEASUREMENTS AND MAIN RESULTS: CTnI was measured before cardiopulmonary bypass (T0) and 12 and 24 hrs after (T12, T24). CK-MB was measured on arrival in the intensive care unit and on the first postoperative day (D1). Patients were divided into three groups according to the type of surgery: coronary artery bypass graft (CABG), valvular surgery (VS), or both procedures. The plasma CK-MB and cTnI concentrations were high in all patients after extracorporeal circulation because of aortic clamping or cardioplegia. The CK-MB and cTnI values were higher in the VS group than in the CABG group. Values peaked at T12 and fell by T24, except when PMI occurred. Eight patients developed a PMI. Patients with PMI had significantly higher cTnI levels at T12 and T24, and higher CK-MB values at D1 than patients without PMI. Cutoff values of cTnI for diagnosing PMI were >19 microg/L at T12 with 100% sensitivity and 73% specificity, and >36 microg/L at T24, with 100% sensitivity and 93% specificity. Lower cTnI values were highly suggestive of the absence of PMI after CABG and/or VS. Other complications such as ST segment changes, ventricular arrhythmias and cardiac failure were indicated by high cTnI levels at T12 and T24. Myocardial protective measures were associated with a nonsignificant increase in cTnI values. CONCLUSIONS: CTnI is more sensitive and specific than CK-MB for diagnosing PMI and other forms of heart failure after cardiac surgery.

Aging prolongs recovery of psychomotor functions at emergence from propofol-alfentanil anaesthesia.

PURPOSE: To compare recovery of psychomotor function in elderly and young surgical patients at emergence from propofol-alfentanil anaesthesia. METHODS: Ten elderly (> 70 yr) and 10 younger (< 40 yr) patients scheduled for orthopaedic surgery of less than three hours, were anesthetized with nitrous oxide, propofol and alfentanil. Propofol and alfentanil cumulative doses, time from cessation of propofol infusion to eye opening (EO) on verbal command and to extubation were recorded. Psychomotor performance was assessed by the Mini-Mental State (MMS) performed the day prior to surgery and postoperatively at 30, 60, and 120 min, following extubation. Propofol blood concentrations were measured at EO and at each MMS task. RESULTS: Elderly patients were comparable with young patients for preoperative MMS scores, surgery and anaesthesia duration, propofol and alfentanil cumulative doses. Postoperative MMS scores were lower at 30, 60 and 120 min, in elderly patients. Propofol blood concentrations were not different between elderly and young patients at EO, 30, 60 and 120 min. CONCLUSION: Psychomotor performance is impaired in elderly compared with young patients at emergence from propofol-alfentanil anaesthesia. These differences are not likely to be related to propofol accumulation in elderly subjects.