Thierry Clerbaux

Comparative study of the oxyhaemoglobin dissociation curve of four mammals: Man, dog, horse and cattle

1. The entire oxygen dissociation curve (ODC) and the effects of temperature, pH and 2,3-diphosphoglycerate (DPG) on this curve, have been compared in four mammalians: man, dog, horse and cattle. 2. If the oxyphoric capacities are similar between these species (around 1.39 ml O2/gHb), their P50, measured in standard conditions, i.e. at pH 7.4; pCO2 40 mmHg and T 37 degrees C, varies between 23.8 (+/- 0.8) mmHg for the horse, 25.0 (+/- 1.4) mmHg for cattle, 26.6 (+/- 1.2) for man and 28.8 (+/- 2.6) mmHg for the dog. 3. The higher dispersion of the dogs P 50 is due to difference between breeds; in seven breeds investigated, the P 50 ranges from 25.8 (spaniel) to 35.8 (hound). 4. We noted no sex difference in the four species. 5. The DPG level is confirmed to be low in cattle (< 1 mumol/gHb) as compared to man (13.5 +/- 2.1 mumol/gHb), horse (16.9 +/- 1.1 mumol/gHb) and dog (19.4 +/- 2.8 mumol/gHb). 6. The oxygen exchange fraction defined as the difference in vol% between a pO2 of 80 and 35 mmHg is, respectively, 3.6 (+/- 0.6) vol% for cattle, 4.0 (+/- 0.4) vol% for the horse, 5.5 (+/- 0.5) vol% for man and 6.6 (+/- 1.7) vol% for the dog. 7. The position and shape of the ODC, as well as T, DPG and pH effects, indicate that the haemoglobin of man and dog seem better adapted to O2 delivery as compared to the horse and cattle.

Hyperbilirubinemia Does Not Interfere with Hemoglobin Saturation Measured by Pulse Oximetry

This prospective clinical study evaluated the influence of high bilirubin plasma levels on the Nellcor pulse oximeter readings (SpO2). Twenty-nine icteric patients (mean total bilirubin 19.2 mg/dl, range 2.3-84.3 mg/dl) were compared with 46 controls. The difference between SpO2 and oxyhemoglobin percentage of hemoglobin (HbO2corr) or fractional saturation as measured by a seven wavelengths Corning Co 2500 Co-oximeter and corrected for the spectral error induced by hyperbilirubinemia in that co-oximeter was greater in icteric patients (bias and precision: 2.9% +/- 2.2% vs. 1.7% +/- 2.7%, P less than 0.03). However, icteric patients had also higher corrected carboxyhemoglobin levels (CoHbcorr) (1.8% +/- 0.7% vs. 1.3% +/- 0.8%, P less than 0.005) due to production of carbon monoxide during the catabolism of hemoglobin. Pulse oximeters read most of CoHb as oxyhemoglobin. After correcting SpO2 for carboxyhemoglobin in both groups of patients, the 99% confidence limits from the obtained regression line were the same in icteric patients (-0.81%, 1.03%) as in controls (-0.89%, 1.08%). There was thus no demonstrable direct influence of high bilirubin plasma levels on SpO2 as measured by a Nellcor pulse oximeter.

Effect of Phosphate On Oxygen-hemoglobin Affinity, Diphosphoglycerate and Blood-gases During Recovery From Diabetic-ketoacidosis

The effects of intravenous phosphate administration on the hemoglobin-oxygen affinity, the 2,3 diphosphoglycerate level and blood gases were investigated in twenty severe diabetic patients with ketoacidosis in the intensive care unit. Ten received phosphate (mean total amount for each patient = 300 mEq) and the others did not. The only significant difference noted in all indices measured during the recovery period of eight days was seen to occur after 48 h; the P50 in vivo (Torr) was slightly higher in the group who received phosphate (22.5±1.6 vs 20.5±2.2) and for the Hill coefficient (2.4±0.2 vs 2.2±0.1). This drop in the oxygen affinity of hemoglobin may be useful in subjects at risk of hypoxia, for example those with cardiac or respiratory failure and justifies the use of phosphate in the first 48 h of treatment of patients with diabetic ketoacidosis.

Effects of two inotropic drugs, dopamine and dobutamine, on pulmonary gas exchange in artificially ventilated patients.

AbstractThe inotropic agents, dopamine (DP) and dobutamine (DB), both decrease PaO2, probably by a resistribution of the

The Effects of Hypertonic Saline in Healthy and Diseased Animals

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Calculation of bovine haemoglobin oxygen saturation by algorithms integrating age, haemoglobin content, blood pH, partial pressures of oxygen and carbon dioxide in the blood, and temperature.

ratio. The aim of this study was to assess the effect of both drugs on the

Influence of age and breed on the binding of oxygen to red blood cells of bovine calves

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