A simple microtonometric method for whole blood oxygen dissociation curve and a critical evaluation of the "single point" procedure for blood P50.

Abstract

We devised a rapid and simple method to obtain oxygen dissociation curve (ODC) for a small amount of blood with simple equipment. This system achieved the gas-blood equilibrium within 3 min. Oxygen saturation of the equilibrated blood was measured spectrophotometrically while the pH, Pco2, and Pot was measured with a Radiometer blood gas analyzer system. Whole procedures to construct ODC from the 6 point measurements could be performed within 1 hr. The standard ODC for 25 normal Japanese adults showed a mean P50 of 27.6±1.1 Torr (pH 7.40, Pco2 40 Torr, 37°C), a slightly higher value than previously reported. The discrepancy, however, can be eliminated when corrected for a slightly lower S02 by the present procedure. The standard curves for the adult blood at pH 7.20 and 7.60 and for the cord blood at pH 7.40 were also described. The "single point" procedure, a much quicker approach to measure the P50 (ABERMAN et al., 1975), was scrutinized by comparing with the "whole curve" method. The P50's by the two methods were not significantly different, mean±S.D. of the differences being 0.4±2.5 Torr (n=126) for the adult blood at pH 7.40, Pco2 40 Torr and 37°C. Similar results were obtained for the adult blood at pH 7.20 and 7.60 and for the cord blood at 7.40. We concluded that the "single point" method was sufficiently accurate and reliable.

Posttransfusional recovery of defective respiratory function of stored blood in dogs.

“…The present procedure, using a spectrophotometric determination of the Sot, is intended for a partial solution of these problems and this aim appears to be achieved fairly well (Table 2). Later the present method has been further modified by the use of the Clark electrode for blood Poz measurement, and the new version enabled us to perform a more rapid and simple determination of whole blood ODC (KOHZUKI et al, 1983). Physiological and biochemical changes of canine blood during storage in ACD.…”

High affinity of blood for oxygen reduces oxygen uptake in contracting canine gracilis muscle

“…The blood oxygen content in millilitres per decilitre (CO2) was calculated from the relationship (Shimizu, Enoki, Kohzuki, Ohga & Sakata, 1986 (Kohzuki, Enoki, Sakata & Tomita, 1983). Red cell 2,3-diphosphoglycerate was measured enzymatically (Maeda, Chang, Benesch & Benesch, 1971 Figure 1 shows representative results from one of the alternate-perfusion experiments.…”

“…HCT was measured using a microhaematocrit centrifuge and haemoglobin (Hb) concentration by the cyanomet-Hb method. P50 (P. of halfoxygenated blood at pH 7-40, PC0, of 40 mmHg at 37°C ) was determined using a single-point method (Kohzuki, Enoki, Sakata & Tomita, 1983). Red cell 2,3-diphosphoglycerate was measured enzymatically (Maeda, Chang, Benesch & Benesch, 1971).…”

Temporal changes of plasma erythropoietin level in hypobaric hypoxic mice and the influence of an altered blood oxygen affinity.

“…oxygen dissociation curves (ODC) were constructed by a modification of the previously reported microtonometric method (KoxzuKI et al, 1983). Conventionally the P50 (P02 for half oxygenation of blood at pH 7.40, Pco2 40 Torr, 37°C) was computed by one-point procedure (ABERMAN et al, 1975).…”