Comparison of Hemodynamic Changes During Induction With Modified Propofol Protocol in Normal and Low Lv Function Patients Undergoing Cabg Surgery

Numerous studies suggested that propofol anesthesia is intuitively appealing for its simplicity, stability and safety, permitting the rapid recovery of patients undergoing cardiac surger. However, its use for induction of anesthesia is often results in transient hypotension. The aim of this study was to determine the safety of modified propofol protocol for induction in low ejection fraction cardiac patients undergoing CABG surgery. Fifty patients with ejection fraction between 30% - 60% who were planned for coronary artery bypass graft surgery were included in this study. Patients were divided into two groups of 25 patients each, according to their left ventricular ejection fractions (EF). Group N (EF between 60%-45%) and Group L (EF between 30%-45%). All the patients were given midazolam/fentanyl/vecuronium and propofol for induction according to pre-defined protocol to prevent hypotension and facilitate early intubation. Hemodynamic variables were registered at fixed points. To prevent hemodynamic compromised situation rescue noradrenaline in 5µg/ml aliquots was kept ready. Amount of propofol used, time taken for successful intubation and grading of jaw relaxation was also done. RESULTS: Four patients in Group L and one patients in Group N encountered significant hypotension (>20% of preoperative value). Amount of vasoconstriction agents used were high in group L. Cardiac index was changed 17.4% from preoperative value and returned to baseline values within 6 min in group L while in group N cardiac index was changed 12.9% from preoperative value and also returned to baseline values within 6 min. Propofol 0.5-1 mg/kg was used to induce hypnosis and all patients were intubated in less than ninety seconds. CONCLUSION: Propofol as induction agent is safe in both low and normal ejection fraction cardiac patients when used judiciously and in titrated doses. Immediate changes in hemodynamic changes can be corrected with mild doses of vasoconstriction agents. BACKGROUND: Total intravenous anesthesia with propofol and low- dose opioids for CABG surgery is now commonly used and is one of the methods that allows early extubation. Fixed dose propofol induction may cause hypotension for about 5−10 min, which is mainly due to the decrease in sympathetic activity and direct vascular smooth muscle relaxation without any direct negative inotropic effect. 1 Even minor haemodynamic changes during induction may lead to severe circulatory problem in patients posted for CABG surgery. This effect is more profound in patients with low left ventricular ejection fraction. Therefore propofol is not routinely used as sole induction agent in that situation. Modified induction technique judicious doses of propofol along with rescue vasopressor agent was described in literature for non-coronary artery cardiac surgery. 2 Preoperative optimization of intravascular fluid status, tredenlenburg position