Body fluid compartment volumes in chronically hypoxemic lambs

Chronic hypoxemia is associated with a decreased growth rate and a decreased rate of cell division. In lambs with experimental cyanotic heart disease, the gain in body mass was decreased. In this study, we determined to what extent the lower body mass in these lambs was related to alterations in body fluid compartment volumes, specifically whether intracellular volume was decreased. Therefore, fluid compartment volumes were studied in nine lambs, after 3 to 4 wk of experimental cyanotic heart disease, and in 13 control lambs. Hypoxemic lambs had a lower arterial oxygen saturation (65 +/- 11 versus 91 +/- 2%, p < 0.001) and a higher Hb concentration (142 +/- 16 versus 101 +/- 8 g.L-1, p < 0.001). The lower body mass in hypoxemic lambs (10.5 +/- 2.3 versus 13.0 +/- 2.8 kg) could be mainly accounted for by a decrease in intracellular water volume (4.7 +/- 1.3 versus 6.6 +/- 1.5 L, p < 0.01). Total body water (753 +/- 27 versus 780 +/- 40 mL.kg-1) and extracellular water volume (307 +/- 25 versus 277 +/- 15 mL.kg-1) in hypoxemic lambs were not significantly different from those in control lambs, but intracellular water volume was decreased (445 +/- 27 versus 501 +/- 35 mL.kg-1, p < 0.01). The ratio of extracellular to intracellular water volume was higher in hypoxemic lambs (0.69 +/- 0.10 versus 0.55 +/- 0.04, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)