Direct measurement of human pulmonary hemodynamics during thoracotomy

Venous admixture effect during one-lung anaesthesia

The venous admixture was measured before, during, and after deflation of one lung during anaesthesia for thoracotomy in 10 subjects ventilated with 50% oxygen. The mean oxygen saturation fell from 99% before deflation of the lung to 89% after 30 minutes’ atelectasis. The pH and carbon dioxide tension did not change significantly. The shunt was 38% of cardiac output five minutes after and 41% 30 minutes after deflation. The reciprocal of the arterial venous oxygen content difference correlated positively with the shunt, suggesting that increased venous admixture is accompanied by increased cardiac output.

A study of Duroziez's murmur of aortic insufficiency in man utilizing an electromagnetic flowmeter

Femoral arterial blood flow was recorded with an electromagnetic flowmeter at the time of open heart surgery on subjects with and without aortic insufficiency. The records demonstrated that subjects with severe aortic insufficiency and Duroziez's murmur had a large amount of retrograde flow in the femoral artery. Those subjects without significant aortic insufficiency and no Duroziez's murmur had little or no backflow. When only a moderate amount of aortic insufficiency was present, the correlation was less satisfactory. In some subjects who had femoral backflow, a second recording was made from the femoral artery after the aortic valve had been replaced, and in these instances there was no longer any measurable backflow. Postoperatively these patients did not have Duroziez's murmur.

It is concluded that Duroziez's crural murmur in subjects with aortic insufficiency is associated with retrograde diastolic femoral arterial blood flow.