Reperfusion injury and exhaled hydrogen peroxide.

Reactive oxygen species have been implicated in the pathophysiology of lung injury associated with the sequence of ischemia-reperfusion. To study this, we measured the exhaled breath hydrogen peroxide concentration [H2O2] in human and canine models of reperfusion lung injury. Our models were patients subjected to cardiopulmonary bypass (CPB) (Group 1), patients undergoing pulmonary thromboendarterectomy (Group 2), canine single lung transplant (Group 3), and patients subjected to peripheral ischemia resulting from aortic cross-clamping or tourniquet application (Group 4).

General anesthesia and exhaled breath hydrogen peroxide.

To study the role of free radical formation on the impairment of pulmonary function seen with general anesthesia, we measured the hydrogen peroxide (H2O2) concentration in the exhaled breath condensate of 27 patients. Patients were divided into three study groups: a healthy patient group (group 1, n = 15) consisting of ASA physical status 1 and 2 patients undergoing elective noncardiothoracic surgery; a specific anesthetic event group (group 2, n = 6) composed of patients undergoing cardiopulmonary bypass (CPB); and a positive control group (group 3, n = 6) consisting of patients with the adult respiratory distress syndrome (ARDS). The exhaled breath condensate was collected by diverting exhaled breath through a glass condensation coil submerged in an ice/salt water bath.