High-dose analgesic anesthesia with morphine or sufentanil in propranolol-treated dogs

In propranolol-pretreated dogs (2 mg . kg -1) the immediate cardiovascular effects of sufentanil (0.01 mg . kg -1) or morphine (4 mg . kg -1) were compared. Besides a 40% decrease in cardiac index (CI), sufentanil and morphine initiated quite different hemodynamic changes. Sufentanil did not significantly change mean arterial pressure (MAP), central venous pressure (CVP) and mean pulmonary artery pressure (MPAP), while the pulmonary capillary wedge pressure (PCWP) increased by 50%. After morphine, MAP declined significantly by about 65%, and significant decreases in MPAP (14%) and PCWP (33%) were also observed. Propranolol reduced heart rate by 16%, and morphine caused no further reduction in HR. A significant decrease of about 30% was seen in HR after sufentanil. Sufentanil significantly raised systemic vascular resistance index (SVRI) by 15%, whereas morphine decreased it by 32%. Pulmonary vascular resistance index (PVRI) was unchanged after sufentanil, but significantly increased after morphine. Right ventricular stroke work index (RVSWI) was unaffected by both analgesics, and morphine decreased left ventricular work index (LVSWI) significantly by 80%. Oxygen transport index declined significantly after both analgesics. Sufentanil reduced oxygen consumption by 20%, while morphine left this parameter unaffected. We conclude that the administration of high-dose sufentanil leads to a stable circulation, even when a total beta-blockade exists.