Simultaneous measurement of serotonin and propranolol pulmonary extraction in patients after extracorporeal circulation and surgery.

To evaluate the use of markers of pulmonary endothelial cell function in humans, we simultaneously measured the pulmonary extraction of serotonin (SER) and propranolol (PROP) in patients before and after extracorporeal circulation (ECC) for coronary bypass surgery. No change was seen in SER extraction ratio after anesthesia, ECC, and surgery. Twenty-four hours after ECC and surgery, PROP extraction ratio was decreased by 11%. It remained low for as long as 5 days thereafter. A similar drop in PROP extraction was found in 6 patients 24 h after ilioaortic bypass surgery, without ECC (from 81 to 66%, p less than 0.01). Treatment of 11 other patients with a 30-min period of continuous positive airway pressure (CPAP), 24 to 48 h after ECC, resulted in a significant increase in PROP extraction ratio from 61 to 67% (p less than 0.01). Measurement of PROP extraction appears to be more sensitive than that of SER to lung changes related to postoperative atelectasis.