Measurement of regional extravascular lung water using the double indicator-dilution isotope technique

Using the formulae of Fazio and coworkers, the regional extravascular lung water per blood volume and flow was calculated in normal volunteers, in patients with left heart failure, sarcoidosis, allergic alveolitis and pneumonia. The double-isotope technique was used. 113mIn-chloride was intravascular tracer and 123I-antipyrine extravascular tracer. They were injected intravenously as rapid bolus. The activity in the lungs was detected with gamma camera and the time-activity curves were generated with PDP-Gamma-11 computer system. Mean transit times were calculated using two different mathematical handlings of the dilution curves, with gamma fitting parameters and by the area-per-height method. The latter method gave mean transit times about double those calculated with gamma fitting parameters, because the peripheral injection decreased the peak height. Therefore, the area per height method to calculate mean transit times by peripheral injection was found to be inaccurate. The control group consisted of 16 healthy adults. In two subjects repeated studies were made in one week. Their individual, regional extravascular lung water values varied somewhat, but were on second examination found to be between the range of the values found from the first examination. The regional extravascular lung water values in patient groups were correlated with corresponding clinical, laboratory and roentgenographic findings. The values for extravascular water discussed on the next page are calculated only by means of transit times with gamma fitting parameters, although the extravascular water values determined by the area-per-height method also significantly increased in patients compared to the control group. The cardiac group consisted of 52 patients, of whom 23 had clinically compensated and 29 decompensated left heart failure. Regional extravascular lung water significantly increased in patients with decompensated heart failure when compared to patients with compensated heart failure. The cardiac group was also divided into three subgroups after radiological grading of pulmonary venous hypertension. Between GR I (n = 17) without signs of venous hypertension and GR II (n = 18) with signs of venous congestion no significant differences in regional extravascular lung water were found. However, in GR I and GR II the values for regional extravascular water increased when compared to the control group, which is probably due to increased perfusion of vessels or increased blood volume in these cardiac patients.(ABSTRACT TRUNCATED AT 400 WORDS)