The Effects of Chronic Hypoxemia on Electrolyte and Acid—Base Equilibrium: An Examination of Normocapneic Hypoxemia and of the Influence of Hypoxemia on the Adaptation to Chronic Hypercapnia*

Sapir, Daniel G.; Levine, David Z.; Schwartz, William B.

doi:10.1172/jci105538

Cited by 26 publications

(8 citation statements)

References 11 publications

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“…Plasma phosphate concentration increased slightly from a mean value of 1.4 to 1.7 mmoles/liter during hypocapnia in the normal NaCl group (P < 0.01 ); no change was observed in the low NaCl group. The mean hemato-'It is noteworthy that an almost identical increase in unmeasured anions not related to a rise in lactate concentration, also occurs in dogs with normocapneic hypoxemia (13). This finding suggests that the increase in unmeasured anions observed in the present study may have occurred in response to hypoxemia rather than hypocapnia.…”

Section: Miscellaneoussupporting

confidence: 61%

“…One might anticipate, for example, that dietary restriction of both sodium and potassium during the period of adaptation would so limit the capacity of the kidney to reduce hydrogen ion excretion, that a marked alkalosis would result. By the 'In chronic hypoxemia unaccompanied by hypocapnia, there is no significant loss of sodium, nor is there any change in net acid excretion (13). These findings indicate that the changes observed in the present study cannot be attributed to the low oxygen tension per se.…”

Section: Discussionsupporting

confidence: 45%

See 1 more Smart Citation

The nature of the renal adaptation to chronic hypocapnia

Gennari¹,

Goldstein²,

Schwartz³

1972

J. Clin. Invest.

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131

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Section: Miscellaneoussupporting

confidence: 61%

Section: Discussionsupporting

confidence: 45%

The nature of the renal adaptation to chronic hypocapnia

Gennari¹,

Goldstein²,

Schwartz³

1972

J. Clin. Invest.

Self Cite

131

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“…It is clear, however, that the hyperbicarbonatemia of the chronic phase is sustained by increased renal hydrogen secretion (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). This study and data from the rat (1) indicate that this process is mediated, in great part, by an increase in the intrinsic rate of bicarbonate reabsorption by the proximal tubule.…”

Section: Discussionmentioning

confidence: 99%

“…This study and data from the rat (1) indicate that this process is mediated, in great part, by an increase in the intrinsic rate of bicarbonate reabsorption by the proximal tubule. The effect of hypercapnia on bicarbonate reabsorption seems specific because it is independent of sodium intake (24), bicarbonate availability and rate of net acid excretion (25), potassium stores (31), mineralocorticoid activity (23), or oxygen tension (27). The present studies establish the cellular mechanism of the increased bicarbonate reabsorption in the proximal tubule in response to chronic respiratory acidosis: adaptation to chronic respiratory acidosis involves stimulation of the luminal Na/H antiporter and the basolateral Na/(HCO3)3 cotransporter.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of adaptation to chronic respiratory acidosis in the rabbit proximal tubule

Krapf

1989

Journal of Critical Care

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The hyperbicarbonatemia of chronic respiratory acidosis is maintained by enhanced bicarbonate reabsorption in the proximal tubule. To investigate the cellular mechanisms involved in this adaptation, cell and luminal pH were measured microfluorometrically using (2M,7')-bis(carboxyethyl)-(5,6)-carboxyfluorescein in isolated, microperfused S2 proximal convoluted tubules from control and acidotic rabbits. Chronic respiratory acidosis was induced by exposure to 10% CO2 for 52-56 h. Tubules from acidotic rabbits had a significantly lower luminal pH after 1-mm perfused length (7.03±0.09 vs. 7.26±0.06 in controls, perfusion rate = 10 nl/min). Chronic respiratory acidosis increased the initial rate of cell acidification (dpH1/dt) in response to luminal sodium removal by 63% and in response to lowering luminal pH (7.4-6.8) by 69%. Chronic respiratory acidosis also increased dpH,/dt in response to peritubular sodium removal by 63% and in response to lowering peritubular pH by 73%. In conclusion, chronic respiratory acidosis induces a parallel increase in the rates of the luminal Na/H antiporter and the basolateral Na/(HCO3)3 cotransporter. Therefore, the enhanced proximal tubule reabsorption of bicarbonate in chronic respiratory acidosis may be, at least in part, mediated by a parallel adaptation of these transporters.

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“…The hypoxemic lambs in our study had no signs of venous congestion either. Water and salt retention in chronic obstructive lung disease was related to hypercapnia rather than to hypoxemia (22,23). In the early phase of (simulated) high-altitude hypoxemia, voluntary sodium and water intake are decreased, and natriuresis and diuresis are increased (24).…”

Section: Discussionmentioning

confidence: 99%

Body Fluid Compartment Volumes in Chronically Hypoxemic Lambs

et al. 1993

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ABSTRACT. 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 2%, p < 0.001) and a higher Hb concentration (142 + 16 versus 101 + 8 g.L-', 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-') and extracellular water volume (307 + 25 versus 277 f 15 mL.kg-') 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-', p < 0.01). The ratio of extracellular to intracellular water volume was higher in hypoxemic lambs (0.69 + 0.10 versus 0.55 2 0.04, p < 0.01). Blood volume was increased in hypoxemic lambs (121 + 29 versus 79 + 15 m L kg-', p < 0.01), mainly due to an increased total red cell volume (48 + 12 versus 22 + 8 mL. kg-',p < 0.001). We conclude that the lower body mass in hypoxemic lambs is mainly related to a lower intracellular water volume. These results and the increased ratio of extracellular to intracellular water volume can be explained by assuming a decreased growth of the intracellular compartment. In addition, a part of the (decreased) growth in hypoxemic lambs must be expended on increased erythropoiesis. (Pediatr Res 33: 267-272, 1993) Abbreviations V,,, extracellular water volume Vi,, intracellular water volume D20, deuteriumoxide i.m., intramuscularly Congenital heart disease is often associated with a decreased growth rate, characterized by a decreased gain in body mass and length (1-3). It seems to affect children with cyanotic heart disease more than children with noncyanotic heart disease (1-3). In young experimental animals exposed to various forms of chronic hypoxemia, a decreased body mass is a common finding (4-8). Based on studies in rats and mice, it has been suggested that a decreased rate of cell division is responsible for the growth retardation (4, 5).The volumes of body fluid compartments change during growth. Both V,, and V,, increase, but per-unit body mass total water and V,, decrease and Vi, increases (9, 10). This can in part be explained by a relatively faster growth of the intracellular compartment (9, 11). In chronic hypoxemia, therefore, body fluid compartment volumes may be altered by the effects of decreased growth.Another factor that may affect fluid compartment volumes is the effect of chronic hypoxemia on blood volume. Blood ...

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The Effects of Chronic Hypoxemia on Electrolyte and Acid—Base Equilibrium: An Examination of Normocapneic Hypoxemia and of the Influence of Hypoxemia on the Adaptation to Chronic Hypercapnia*

Cited by 26 publications

References 11 publications

The nature of the renal adaptation to chronic hypocapnia

The nature of the renal adaptation to chronic hypocapnia

Mechanisms of adaptation to chronic respiratory acidosis in the rabbit proximal tubule

Body Fluid Compartment Volumes in Chronically Hypoxemic Lambs

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