Early hemodynamic and respiratory changes following tourniquet release - influence of large doses of methylprednisolone.

The early hemodynamic and respiratory response 5 and 15 minutes after tourniquet release in 26 patients operated upon for osteoarthrosis of the knee was studied. Fourteen randomly selected patients received 30 mg/kg of methylprednisolone before releasing the tourniquet, while 12 patients served as control. Cardiac output remained unchanged in the steroid group, but fell significantly in the control group, while mean arterial pressure fell to the same level in all patients. Systemic vascular resistance was lowered in all patients but significantly more so in the steroid group, who also had lower pulmonary vascular resistance. Pa02 fell significantly in all patients after tourniquet release implying pulmonary microembolism. The oxygen consumption increased after tourniquet release in the steroid group, which together with the lower systemic vascular resistance indicates a better nutritive blood flow in the leg. The lower pulmonary vascular resistance in steroid patients resulted in a higher pulmonary capillary flow which however went to non- or poorly ventilated parts of the lung, seen as an increased intrapulmonary shunt. The shunt was unaffected in the control group. The improved leg and pulmonary blood flow indicates a beneficial effect of steroids on patients with fractures in combination with ischaemia.