Adv Exp Med Biol
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Clinical Trial Controlled Clinical Trial
The Haldane effect under different acid-base conditions in premature and adult humans.
The Haldane effect (HE) was investigated in human adults and prematures under normal metabolic acid-base conditions but at different levels of PCO2. Venous blood samples were equilibrated with low and high PCO2 in either O2 or N2. The change in plasma pH of oxygenated blood by deoxygenation did not differ between both groups. ⋯ Likewise, HE-correction is important for indirect estimation of metabolic acid-base status (BE and HCO-3st) from clinical routine PCO2- and pH-measurement. In spite of the vaste amount of literature on the Haldane effect in human blood, quantitative data for practical purpose are less available and still equivocal. By the present study, a strong inverse linear correlation between the HE-induced delta pH and 1g[HCO3-] could be shown over a wide range of acid-base changes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Septic shock and ARDS are associated with disturbed tissue oxygenation. It has been suggested to increase O2 supply (DO2) above the normal level (> 600 ml/min/m2) to compensate for the tissue hypoxia. The lack of a rise in O2 consumption (VO2) after increases of DO2 has been presumed to indicate adequate tissue oxygenation (negative O2 flux test). ⋯ An additional increase of DO2 by colloidal volume substitution caused a significant rise of pHi from 7.20 +/- 0.05 to 7.25 +/- 0.05 but did not change VO2. We conclude that a negative O2 flux test does not rule out regional tissue hypoxia, and second, an increase in DO2 may improve tissue oxygenation without measurable changes in VO2. Furthermore, adequate volume substitution is an important step in the treatment of septic shock to increase total body blood flow and more specifically regional blood flow.