Early response in central hemodynamics to high doses of sufentanil or morphine in dogs

Abstract

The hemodynamic effects of high doses of sufentanil, a newly synthetized highly potent analgesic, were investigated in dogs. This study compared the early (30 min) cardiovascular effects of sufentanil 0.01 mg . kg-1 and morphine 4 mg . kg-1. Sufentanil caused a moderate and insignificant decrease in mean arterial pressure (MAP). A 30% decrease in cardiac index (CI) was almost outbalanced by an increased systemic vascular resistance (SVRI). The lowering of CI was due to a more than 50% decrease in heart rate (HR) which was partly compensated for by a greater stroke volume index (SVI). In the first 5 min after morphine injection, MAP fell significantly to about 50 mmHg (below 50% of the control value). CI was reduced to about 50% of the control value because of significant decreases in both SVI and HR. The calculated SVRI was unchanged after morphine. Within 30 min some of the initially changed parameters had returned to control levels. Central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) increased immediately after sufentanil, but decreased after morphine. With time, both parameters returned towards control values. Peak left ventricular dP/dt decreased by about 25-50% after both analgesics. The rate-pressure products (RPP) were significantly decreased to less than one half of the control values after both analgesics. Mixed venous oxygen tension (PVO2), oxygen transport and oxygen consumption were significantly lowered in the sufentanil group, whereas immediate decreases after morphine were followed by gradual increases towards control values. We conclude that the use of high doses of sufentanil in dogs is safe. Apart from initial, transient changes, a stable cardiovascular state characterizes the high-dose sufentanil anesthesia, while morphine causes fluctuations in several hemodynamic parameters. Compared to morphine anesthesia, sufentanil anesthesia appears to be an attractive alternative which deserves further evaluation in humans.