Clinical correlates of the spectrum of lung microvascular injury in human noncardiac edema

Abstract

We measured the clearance from blood to pulmonary edema fluid of a small molecular weight hydrophilic radiotracer, Indium-111-DTPA (In-DTPA) and a larger molecular weight radiotracer, Iodine-125-HSA (I-HSA), in patients with pulmonary edema on either a cardiac or noncardiac (permeability) basis. In previous investigations, we had noted an apparent relationship between the magnitude of clearance of I-HSA across the alveolocapillary membrane and the severity of noncardiac pulmonary edema. In this study, we were able to distinguish at least 2 distinct groups of patients with noncardiac pulmonary edema. Patients with the greatest damage to the alveolo-capillary exchanging membrane, defined by the flux of I-HSA from blood to edema fluid, were significantly differentiated from those with a lesser microvascular injury on the basis of higher mean heart rate (HR), temperature, cardiac index (CI), pulmonary artery pressures, right ventricular stroke work index (RVSWI), and a lower mean total white blood cell count (WBC), among others. Therefore, noncardiac pulmonary edema is characterized by a spectrum of permeability injury to the pulmonary microvasculature which seems to parallel other measurable indices of the severity of the systemic response to the illness.