Effect of Pancuronium on Plasma Free‐Norepinephrine and Epinephrine in Adult Cardiac Surgical Patients

Abstract

Since diazepam-ketamine induction sequences in healthy humans cause no significant increase in plasma free-norepinephrine and epinephrine, blood pressure and heart rate, we have frequently used a diazepam-ketamine pancuronium sequence for induction of anesthesia in patients undergoing open-heart surgery. I n order to assess objectively the influence of pancuronium on sympathetic activity in cardiac patients, plasma free-norepinephrine and free-epinephrine were measured by Vendsalu's method in the arterial blood of 12 patients who were to undergo valve replacement or coronary bypass. At the same time, arterial pressure measured by a strain-gauge from the radial artery and heart rate measured by ECG were continuously recorded during induction with diazepam 0.3 mg/kg, followed 10 min later by ketamine 2.0 mg/kg. No significant changes occurred in these parameters before pancuronium administration. Plasma free-norepinephrine and free-epinephrine concentrations before and 5 min after pancuronium 0.1 mg/kg given over a 1-min period were 0.42iz0.05 (mean+s.e.mean) and 0.45k0.05 ng/ml (P>O.l) and 0.01 k0.003 and 0.02t0.009 ng/ml (P>O.l), respectively. A significant increase in heart rate followed pancuronium administration from 75.0 f 4.0 to 90.0 f6.0 beatslmin (P 50.001). The corresponding systolic and diastolic direct arterial pressures were 148.0+9.4/74.0+6.0 and 153.0*8.3/81.0*5.2 mmHg (P> 0.05). Although a statistically significant increase in heart rate was observed after pancuronium, no significant increase was found in plasma free-norepinephrine, epinephrine or direct arterial pressure.