Effect of Muscle Relaxants on Heart Rate, Arterial Pressure, Intubating Conditions and Onset of Neuromuscular Block in Patients Undergoing Valve Surgery

It is important to maintain haemodynamicstability during anaesthetic induction, in patients undergoing surgery for valvular heart disease (VHD). The common practice includes, use of high dose opioids and nondepolarising muscle Sixty six patients undergoing elective valve surgery were randomized to receive rocuronium bromide 0.6 mg/Kg (Group R, n=22), pancuronium bromide 0.1 mg/Kg (Group P, n=22) and vecuronium bromide 0.1 mg/Kg (Group V, n=22). Measurements of heart rate and arterial pressure (systolic, diastolic and mean) were noted at the following stages: 1) baseline when haemodynamics were stable for 2 minutes after induction of anaesthesia (2) one, (3) three, (4) five minutes after administration of muscle relaxants, (5) one, (6) three, and (7) five minutes after intubation. In group R, the heart rate decreased 5 min after injection of muscle relaxant from 93.9±21.3 to 82.4±20.7 beats / min (p<0.001). However, it increased to 128.3 ± 25.8 beats / min (p<0.001) following intubation and returned to baseline at 5 min after intubation. In group P, heart rate increased from 98.8±32.6 to 109.6±32.7 beats/min (p<0.001), 1 min after injection of pancuronium and this increase persisted throughout the study period. In group V, heart rate decreased from 99.9±22.3 to 83.8±19.6 beats/min (p<0.001) at 5 min after injection of the drug. It increased to 118.