GAMMA-SCINTIGRAPHIC ANALYSIS OF ALBUMIN FLUX IN PATIENTS WITH ACUTE RESPIRATORY-DISTRESS SYNDROME

  • 1 January 1984
    • journal article
    • research article
    • Vol. 95  (6) , 674-682
Abstract
Computerized .gamma.-scintigraphy provides a new method for the analysis of albumin flux in patients with pulmonary permeability edema. In this technique, 10 mCi [Curie] of 99mTc-tagged human serum albumin is administered and lung; heart radioactivity ratios are determined. This ratio remains constant unless there is a leak of albumin, when a rising ratio with time, called the slope index (SI), is seen. Scintigraphic studies (35) were obtained in 28 patients by means of a portable computerized .gamma.-camera. Thirteen of these patients had clinical evidence of the acute respiratory distress syndrome (ARDS) and 6 had or were recovering from left ventricular induced congestive heart failure (CHF). Five of the patients with CHF and pulmonary capillary wedge pressure (PCWP) below 30 mm Hg had normal scintigraphic studies. One patient in florid CHF with a PCWP of 40 mm Hg had a positive SI of 1.6 .times. 10-3 U/min. The patients with ARDS were found to have significantly higher SI than patients who did not have, or had recovered from, ARDS. The arterial:alveolar O2 tension ratio (a/A)O2 was 0.30 .+-. 0.14 in patients with positive SI while receiving 11.0 .+-. 6.8 m H2O positive end-expiratory pressure (PEEP). Both the (a/A)O2 and level of PEEP were significantly (P < 0.01) worse in these patients than in patients with normal SI. Positive SI were present from 1-8 days following the apparent onset of ARDS in 7 studies of 5 patients. Recovery of gas exchange was associated with a return to a normal SI in 4 patients. Computerized .gamma.-scintigraphy was a sensitive, noninvasive tool for the findings were associated with significantly impaired gas exchange. The method documented that the leak of albumin in patients with ARDS may last for days but resolves with recovery.