Comparison of neurological outcomes in patients undergoing conventional coronary artery bypass grafting, on-pump beating heart coronary bypass, and off-pump coronary bypass.

OBJECTIVE: To study the differences in the prevalence of neurological complications following coronary artery bypass (CAB) carried out by conventional, on-pump beating and off-pump techniques. METHODS: A retrospective analysis of all isolated coronary bypass operations (n=127) performed in King Fahad Cardiac Center, Riyadh over a period of one year starting from January 2005. Out of 127 patients, 73 underwent conventional CAB graft (CABG), 33 patents on-pump beating heart coronary bypass, and 21 had off pump coronary bypass grafting (OPCAB). All patients had preoperative carotid scans and those who developed neurological complications underwent CT-brain and expert neuro-psychiatric assessment. RESULTS: Preoperative characteristics of patients in all 3 groups were similar. The bypass times in the conventional CABG group were significantly longer than the on-pump beating group. The maximum number of grafts was in the on-pump beating group, followed by the conventional CABG, and the least in the OPCAB group. Seven out of 73 cases in the conventional bypass group developed neurological events of various severities. Only one out of 33 patients developed acute confusional state in the on-pump beating group and no neurological events were noticed in 21 patients operated by the OPCAB technique. Low ejection fraction, preoperative congestive cardiac failure, non-elective surgery and preoperative catastrophic state were found to be significant risk factors independent of the bypass technique. CONCLUSION: This study shows no significant difference in the prevalence of neurological complications among different types of bypass surgery in our institution. There was a trend towards less neurological outcomes in the OPCAB and on-pump beating groups.

The effects of melatonin premedication on propofol and thiopental induction dose-response curves: a prospective, randomized, double-blind study.

BACKGROUND: The effect of melatonin on the intraoperative requirements for i.v.anesthetics has not been documented. We studied the effect of melatonin premedication on the propofol and thiopental dose-response curves for abolition of responses to verbal commands and eyelash stimulation. METHODS: This prospective, randomized, double-blind study included 200 adults with ASA physical status I. Patients received either 0.2 mg/kg melatonin or a placebo orally for premedication (n = 100 per group). Approximately 50 min later, subgroups of 10 melatonin and 10 placebo patients were administered various doses of propofol (0.5, 1.0, 1.5, 2.0, or 2.4 mg/kg) or thiopental (2.0, 3.0, 4.0, 5.0, or 6.0 mg/kg) for anesthetic induction. The ability of each patient to respond to the command, "open your eyes," and the disappearance of the eyelash reflex were assessed 60 s after the end of the injection of propofol or thiopental. Dose-response curves were determined by probit analysis. RESULTS: Melatonin premedication decreased thiopental ED50 values for loss of response to verbal command and eyelash reflex from 3.4 mg/kg (95% confidence interval, 3.2-3.5 mg/kg) and 3.7 mg/kg (3.5-3.9 mg/kg) to 2.7 mg/kg (2.6-2.9 mg/kg) and 2.6 mg/kg (2.5-2.7 mg/kg), respectively (P < 0.05). Corresponding propofol ED50 values decreased from 1.5 mg/kg (1.4-1.6 mg/kg) and 1.6 mg/kg (1.5-1.7 mg/kg) to 0.9 mg/kg (0.8-0.96 mg/kg) and 0.9 mg/kg (0.8-0.95 mg/kg), respectively (P < 0.05). CONCLUSIONS: Melatonin premedication significantly decreased the doses of both propofol and thiopental required to induce anesthesia.

Timing of revascularization after acute myocardial infarction.

The optimal timing of surgical revascularization after acute myocardial infarction remains controversial. Higher mortality after emergency coronary artery bypass has been documented. We retrospectively reviewed 278 patients who underwent coronary artery bypass between 2005 and 2007. The time from onset of myocardial infarction to surgical revascularization was the basis for dividing patients into 3 groups: surgery was performed within 24 h in group 1, at 24-72 h in group 2, and after 14 days in group 3. There was a definite relationship between the timing of revascularization and the outcome of surgery. Group 1 had a mortality rate of 11.7%, group 2 had 7% mortality, and group 3 had 2.5% mortality. Group 1 had the highest incidence of postoperative complications. Surgical revascularization within 24 h of acute myocardial infarction was associated with significantly higher risks of mortality and morbidity than procedures performed after 72 h.