Studies of Peripheral Circulation during Sickle-Cell Crisis

In 18 Negro patients with sickle-cell anemia or sickle cell-hemoglobin C disease, gradients of oxygen and pH were measured between brachial artery and superficial and deep venous system of the upper extremity. The results obtained during crisis were compared with those obtained from asymptomatic patients. Arterial oxygen unsaturation, with normal arteriovenous gradients for oxygen and pH was observed in the 11 asymptomatic patients. Unusually low arteriovenous gradients for oxygen and pH, mainly due to abnormal venous values, were found when blood draining from cutaneous areas was compared with arterial samples in the 7 patients studied during acute crisis. The 5 patients restudied after symptoms subsided showed a return toward normal of arteriovenous differences. The evidence suggests that during crisis arterialization of venous blood is the result of anatomic or functional by passes in the superficial circulation, so that oxygen is not removed by the tissues. It is postulated that a vascular neurogenic mechanism may be the precipitating factor in sickle-cell crisis. It is also suggested that a low arteriovenous oxygen gradient or arterialization of superficial vein blood may be used as a laboratory aid in establishing the diagnosis of sickle-cell crisis in uncertain cases.