Cardiovascular Effects of Meperidine‐N2O Anesthesia Before and After Pancuronium

The cardiovascular effects of 2 and 3 mg/kg of meperidine plus 60 to 67% N2O in O2 on cardiovascular dynamics in man were measured before and after the administration of 0.08 mg/kg of IV pancuronium. N2O and 2 mg/kg of meperidine did not change heart rate (HR) but produced a marked reduction (−49%) in cardiac output (&OV0422;T) plus significant decreases in stroke volume (SV) and blood pressure (BP) and an increase in peripheral arterial resistance (PVR). Additional meperidine did not further alter any of the variables; however, surgical stimulation caused significant increases in HR, BP, and PVR. SV and &OV0422;T were not significantly changed by surgical stimulation and were still markedly depressed when compared to control values. Pancuronium produced marked increases in HR, SV, &OV0422;T, and BP and a reduction in PVR. These changes were maximal 4 to 8 minutes after pancuronium and returned toward pre-pancuronium values thereafter. These data demonstrate that N2O-meperidine anesthesia results in a moderate reduction in BP but a marked depression in &OV0422;T. The findings also indicate that pancuronium reverses the cardiovascular depression produced by N2O-meperi-dine and is therefore, a desirable muscle relaxant when the above technic is employed.