Anesthetic Depth Control Using CLADS vs. TCI in Patients With LVSDF

Advancement in techniques for anaesthetic drug delivery and real time monitoring has facilitated safe induction and maintenance of anaesthesia in severely compromised patients. Cardiac diseases are the commonest causes of morbidity and left ventricular failure is the commonest clinical presentation at the end stage. LV systolic dysfunction is defined as reduction in LVEF ≤55%. Patients with LVEF 55%-46% have mild, 45%-36% moderate and ≤35% severe LV systolic dysfunction. Patients with heart failure have a diminished cardiac reserve capacity that may be further compromised by anaesthesia. In addition to depression of sympathetic activity, most anaesthetics interfere with cardiovascular performance, either by a direct myocardial depression or by modifying cardiovascular control mechanisms. Propofol with fentanyl is advocated as the best anaesthetic combination for induction of anaesthesia in patients undergoing CABG. Propofol is a drug with narrow therapeutic index and may cause severe hypotension and hemodynamic instability during induction of anaesthesia, especially if it is given in too large doses. Automated drug delivery systems are popular for delivery of propofol. They can be of two types, depending on whether they are based on pharmacokinetic or pharmacodynamic principles. Closed Loop Anaesthesia Delivery system has been used world-wide and in our institute in patients of various age groups and in patients undergoing cardiac surgery. But still the studies are lacking in patients with moderate to severe left ventricular systolic dysfunction. Moreover none of the studies have compared the efficacy of anaesthetic drug delivery using these two devices in this group of patients. Thus there is paucity of literature regarding PK and PD of propofol in patients with cardiac failure. The investigators hypothesized that as the Closed Loop Anaesthesia Delivery System is based on pharmacodyanamic principles, it should perform better than the Target Control Infusion syste