Extracellular body fluid volumes in chronically hypoxemic lambs
Dalinghaus, M.; Gerding, A.M.; Koers, J.H.; Gratama, J.W.C.; Kuipers, J.R.
Pediatric Research 21(4 Part 2): 189A
ISSN/ISBN: 0031-3998 DOI: 10.1203/00006450-198704010-00136
The extent to which body fluid volumes change as a consequence of chronic hypoxemia is not exactly known. Therefore we measured extracellular and plasma volumes in 5 chronically hypoxemic lambs. Before the 10th day of life we placed an inflatable balloon around the pulmonary artery, performed an atrial septostomy and inserted catheters. On days 3-4 after surgery the balloon was gradually inflated. In another 7 lambs only catheters were placed. At 5 weeks of age the lambs were studied. We used single injections of ferrocyanide and Evans blue to measure extracellular and plasma volumes, respectively. The hypoxemic lambs had a lower aortic oxygen saturation (69±9 (SD) vs 92±2%, p<0.01), and a higher hemoglobin concentration (142±17 vs 97±10 g.1−1, p<0.001) and hematocrit (43±5 vs 29±6%, p<0.01). Total extracellular fluid volume (320±31 vs 273±17 ml·kg−1 p<0.01) and blood volume (134±33 vs 80±12 ml·kg−1, p<0.05) were increased in hypoxemic lambs. This was also true for plasma volume (81±22 vs 58±5 ml·kg−1) and interstitial fluid volume (238±29 vs 215±18 ml·kg−1), although these differences did not reach statistical significance. These results show that total extracellular fluid volume and blood volume are both increased in hypoxic lambs, and that total hemoglobin mass is even more increased than the hemoglobin concentration would lead us to expect.