Detection of intrapulmonary hemorrhage with carbon monoxide uptake. Application in goodpasture's syndrome

We devised a noninvasive measure of pulmonary hemorrhage of value in the management of Goodpasture's syndrome. We reasoned that alveolar uptake of inhaled carbon monoxide during breath holding would increase in the presence of extravascular blood, but clearance of its radioisotope (C15O) from a lung field would be delayed. Thus, the ratio of uptake to clearance would indicate lung hemorrhage. In 15 controls and six patients with renal failure without hemorrhage, this ratio ranged from 0.73 to 1.5. In eight patients with Goodpasture's syndrome the ratio ranged from 1.5 to 16.5, returning to normal between episodes of bleeding. Measurements of carbon monoxide uptake alone in 10 patients with Goodpasture's syndrome were at times well above that predicted for their hemoglobin level, whereas in renal failure with acute pulmonary edema increased carbon monoxide uptake was rarely found. Thus, monitoring of the single-breath carbon monoxide uptake alone can detect episodes of lung hemorrhage.