sodium-bromide and Lung-Diseases--Obstructive

It was previously demonstrated that single frequency bio-electrical impedance (BIA) measurement at 50 kHz is a useful method to assess total body water (TBW) in patients with chronic obstructive pulmonary disease (COPD). In the present study it was examined whether bio-electrical impedance spectroscopy (BIS) could predict extracellular water (ECW) and improve the prediction of TBW in these patients. TBW and ECW (corrected bromide space) were measured by deuterium and bromide dilution. In 37 COPD patients prediction equations were obtained using BIS (5-500 kHz) measurements, and these were cross validated in a second group of 40 COPD patients. All patients were in a clinically stable condition. TBW predicted by BIS was not significantly different from actual TBW and demonstrated a comparable standard error of estimate (SEE) as found previously in healthy subjects (male symbol correlation coefficient: r = 0.88, SEE: 2.3 L, female symbol r = 0.85, SEE: 2.9 L). Predicted ECW using BIS-measurements was not significantly different from measured ECW (male symbol r = 0.75, SEE: 1.4 L, female symbol r = 0.73, SEE: 1.2 L), but the error in the prediction was relatively large and the correlation between predicted and actual ECW relatively low compared to most studies in healthy subjects. Predicted TBW using BIS was comparable to actual TBW, but presented no improvement of the prediction of TBW using BIA at 50 kHz and a patient specific regression equation. The error of the prediction of ECW by BIS limits the ability to predict fluid shifts in individual patients with clinically stable COPD.

Topics: Aged; Body Composition; Body Height; Body Water; Bromides; Computer Simulation; Deuterium; Electric Impedance; Extracellular Space; Female; Humans; Lung; Lung Diseases, Obstructive; Male; Middle Aged; Reference Values; Sodium Compounds

Tissue depletion often occurs in patients with chronic obstructive pulmonary disease (COPD), even in those that are weight-stable. Limited data are available, however, about changes in body water compartments in chronic wasting diseases such as COPD. The purpose of this study was to measure body composition in severe COPD patients with special attention to fat-free mass (FFM) depletion and the distribution of body water compartments. Total body water (TBW) and extracellular water (ECW) were measured by deuterium and sodium bromide dilution techniques, respectively, in 38 COPD patients (age: 65 +/- 9 y, forced expiratory volume in 1 s: 38 +/- 14% of predicted) in a stable clinical condition. FFM was calculated by assuming a hydration coefficient of 73%. Underweight patients [body mass index (BMI; in kg/m2) < or = 21] were characterized by a significantly lower percentage fat mass than normal-weight patients, but no significant difference was found in the ratio of ECW to intracellular water (ICW)(BMI < or = 21: 0.72 +/- 0.12, BMI > 21: 0.71 +/- 0.16; NS). When the study population was divided into depleted patients (FFM/height2 < or = 15 kg/m2) and nondepleted patients (FFM/height2 > 15 kg/m2), there was no significant difference in the percentage fat mass, but the ECW-ICW ratio was significantly higher in the depleted patients (0.78 +/- 0.16) than in the nondepleted patients (0.66 +/- 0.12, P < 0.05); this was most pronounced in women. In conclusion, it was found that COPD patients with extreme FFM wasting are characterized by an increased ECW-ICW ratio despite a relatively spared fat mass.

Topics: Aged; Body Composition; Body Mass Index; Body Water; Bromides; Deuterium; Extracellular Space; Female; Humans; Linear Models; Lung Diseases, Obstructive; Male; Middle Aged; Sodium Compounds