Variability of oxygen affinity of blood: human subjects native to high altitude

Abstract

Whole blood O2 equilibrium curves (OEC) were measured in 46 Peruvians native to high altitude (4,540 m) and in 25 sea-level controls. A method was employed that records the entire OEC from 0 to 150 Torr with constant pH and PCO2. The data were analyzed by fitting the Adair equation describing the successive oxygenation of hemoglobin. At pH 7.4 the PO2 at which hemoglobin is half-saturated with O2 (P50) was significantly higher in the high-altitude population (31.2 +/- 1.9 Torr) than in controls (29.2 +/- 1.8 Torr, P less than 0.001). The acid-base status of the high-altitude subjects, however, was that of compensated respiratory alkalosis (plasma pH 7.439 +/- 0.065), and when the P50's were corrected to the subjects' plasma pH the values (30.1 +/- 2.2 Torr) could no longer be distinguished from the controls. We conclude that, on the average, increased P50 resulting from increased red cell 2,3-diphosphyoglycerate concentration at high altitude is offset by compensated respiratory alkalosis with the net result that the position of the OEC more closely approaches that of sea-level humans than has hitherto been thought. Considerable variation exists in P50, both at sea level and high altitude. This variation might have important consequences for acclimatization and survival under adverse environmental conditions.

The in-vivo oxyhaemoglobin dissociation curve at sea level and high altitude

“…While the increase in pH and decrease in PCO 2 are known to shift the ODC to the left, increases in [2, are known to shift the ODC to the right. Previous studies that were performed in vitro have reported that these effects cancel each other out under physiological conditions at high altitude (Winslow et al, 1981;Winslow et al, 1984;Wagner et al, 2007). However, both of our groups of subjects at high altitude exhibited marked leftward shifts in their in vivo ODCs.…”

“…(Aberman et al, 1976 were dissatisfied with the conflicting results from previous studies. They Winslow et al (1981) used a technique to plot the entire ODC rapidly and accurately under both standard and physiological conditions. This method was first applied to a population at sealevel, where it was found that there is great variation in P 50 (Winslow et al, 1978).…”

High-altitude diving in river otters: coping with combined hypoxic stresses

“…(Ostojic et al, 2002), deer mouse (Peromyscus sp.) (Snyder et al, 1982), domestic cat (Felis catus) and dog (Canis familiaris) (Cambier et al, 2004), Andean and sea-level human (Winslow et al, 1981), Himalayan human (Samaja et al, 1979), fox (Dusicyon sp.) and puma (Puma concolor) (León-Velarde et al, 1996a), guinea-pig (Cavia sp.)…”

The Effect of High or Low Oxygen Affinity Red Cells on Tissue Oxygenation and Myocardial Function in Hypoxic Newborn Lambs with or without Hypercapnia

“…Because hyperbili-atrium was never greater than 2%, indicating that there was no rubinemia is frequent in these infants, many of them are exchange left-to-right shunt through the ductus arteriosus. Samples obtained transfused with adult blood (Pm,(27)(28).…”

“…Because hyperbili-atrium was never greater than 2%, indicating that there was no rubinemia is frequent in these infants, many of them are exchange left-to-right shunt through the ductus arteriosus. Samples obtained transfused with adult blood (Pm,(27)(28).from descending aorta and pulmonary artery were used to deterIn order to evaluate whether the manipulation of oxygen affinity mine pH, Pon Pcos, hemoglobin concentration and HbOn using could result in observable differences in cardiovascular function instruments from Instrumentation Laboratory Inc. Lexington, MA and tissue oxygenation during severe hypoxia, a study was planned (213 blood gas analyser tonometer, 208 gas mixing system, 182 to simulate severe respiratory failure in the neonatal period. co-oximeter).…”