Comparison of rocuronium, vecuronium and atracurium in tiva for hemodynamic effects during beating heart bypass surgery

Aims: Patients requiring coronary artery bypass graft surgery are usually in compromised cardiac status and factors altering the myocardial oxygen demand and supply ratio, like, changes in heart rate, systolic diastolic and mean arterial blood pressure, myocardial contractility and vascular resistance may aggravate the underlying problem. Aim of our study was to compare the hemodynamic effects of neuromuscular blocking drugs like rocuronium, vecuronium and atracurium in patients undergoing elective coronary artery bypass graft (CABG) under Total intravenous anaesthesia. Materials and Methods: Total of 90 cases were studied who were posted for elective beating heart CABG surgery, and were categorized into 3 groups with 30 patients in each group. Patients in group A were given vecuronium and group B and group C patients were administered with rocuronium and atracurium respectively, before intubation and for maintenance according to standard calculated doses. Hemodynamic parameters like HR, MAP, MPAP, PCWP, CI, SVI etc are measured at critical events and data analysed for assessing hemodynamic stability following use of the above said skeletal muscle relaxants. Results: Overall vecuronium group was shown to be associated with decrease in HR, MAP, while other parameters were maintained. In rocuronium group there were increases in HR, MAP, MPAP, PCWP, CI, SVI, SVR, which were statistically significant but clinically not that significant. In atracurium group there was decrease in HR, MAP, MPAP, PCWP, CI, SVI, SVR which were significant but clinically not that significant. From the present study it was concluded that vecuronium had a better and more cardiac favorable variables and more cardiovascular stability when compared to rocuronium and atracurium. Rocuronium was more cardio stable than atracurium. Vecuronium >Rocuronium >Atracurium (>=is better than). Introduction Coronary artery bypass graft surgery (CABG) commonly known as heart bypass surgery is a surgical intervention to reduce mortality and morbidity in patients suffering from significant coronary artery disease. Anaesthesia for coronary bypass surgery is challenging as we have to maintain the hemodynamic stability to avoid cardiovascular accident during surgery. Cardiovascular stability is an important determinant in choosing muscle relaxants. Although anaesthetic goals for bypass surgery are identical to any other procedures, drugs available for achieving these goals are affected by the unique requirements in these patients, like maintaining myocardial oxygen demand and supply ratio consequently strictly adhering to control Heart rate, pressure changes and left ventricular function. Commonly used Vecuronium is associated with bradycardia, while atracurium is associated with histamine release. Another new long acting neuromuscular blocking agent rocuronium has faster onset of action and duration of action is similar to that of Vecuronium. This drug belonging to aminosteroidal group has not been studied widely for it's cardiovascular stability, although some initial neuromuscular studies have raised few important concerns. Neuromuscular blocking drugs interact with nicotinic and muscarinic cholinergic receptors within the sympathetic and parasympathetic nervous system and at the nicotinic receptors of the NM junction. Dose response ratios can be derived by comparing the potencies of muscle relaxants in blocking the neuromuscular junction at muscle (ED 95) with their potencies in blocking parasympathetic or sympathetic ganglion transmission (ED). The higher the dose ratio, the lower the likelihood or the greater the safety ratio for the occurrence of the particular autonomic effect. The side effect is absent (none) in clinical practice if the safety ratio is 3 or 4, moderate if 2 or 3, and strong or prominent if ratio is 1 or less. The side effect of histamine release is most Article Info Received: 5th April, 2019 Accepted: 14th June, 2019 Published Online: 22nd August, 2019