Electrical impedance measured changes in thoracic fluid content during thoracentesis.
In patients (seven females and 11 males) with pleural effusion due to pulmonary (n = 13) or cardiac disease (n = 5) the change in baseline transthoracic impedance (Z0) was measured by electrical impedance (BoMed's NCCOM-3, 70 kHz) during thoracentesis. Data were obtained before and after withdrawal of each 500 ml, and at the end of the thoracentesis. We found a close linear correlation (r = 0.97) between changes in Z0 and the volume of aspirated pleural effusion (y = 0.415.x+0.093). The variability of the estimated thoracic fluid volumes was analysed with a plot of the residuals from the regression line, and we found that changes in thoracic fluid volume estimated by impedance technique would be within +/- 302 ml (= 2 SD). However, the absolute value of Z0 before thoracentesis could not differentiate the group of patients with pleural effusion from normal subjects (n = 28).
Department of Pulmonary Medicine P/Chest Clinic, Bispebjerg Hospital, Copenhagen, Denmark.
J R
JR
Petersen
B V
BV
Jensen
H
H
Drabaek
K
K
Viskum
J
J
Mehlsen
D000368:Aged; D000369:Aged, 80 and over; D001826:Body Fluids / Q000378:metabolism; D002307:Cardiography, Impedance; D005260:Female; D006331:Heart Diseases / Q000378:metabolism* / Q000628:therapy; D006801:Humans; D001239:Inhalation; D008171:Lung Diseases / Q000378:metabolism* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000378:metabolism