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T Clerbaux

Publications and source records attributed to T Clerbaux.

At least 19 recordsLinked to original sources
PubMed1992

Reestimation of the effects of inorganic phosphates on the equilibrium between oxygen and hemoglobin.

In a previous paper, published in this journal, we showed that the data obtained in patients with severe ketoacidosis suggest that inorganic phosphates (K2HPO4) can increase their P50 and therefore enhance tissue oxygenation without concomitant alteration of the 2,3 diphosphoglycerate (DPG). In order to test the hypothesis that K2HPO4 could influence the oxyhemoglobin dissociation curve (ODC) by a mecanism which was not DPG mediated we have measured the total ODC on whole blood with and without addition of 13-80 mmol/l of inorganic phosphates. On average, the level of DPG remained unchanged when the P50 with K2HPO4 was significantly higher (p greater than 0.001) (P50 = 29.9 +/- 3.7 mmHg) than when phosphates were not administered (P50 = 25.5 +/- 2.8 mmHg). The relationship between P50 (mmHg) and K2HPO4 (= X mmol/l) was delta P50 = -2.97 10(-3)(X)2 +0.26(X)-0.42 (r = 0.78). Seeing that phosphates have an immediate action on the ODC, we calculated in our ketoacidosis patients, the relationship between the P50, the inorganic phosphates (P(i) in mg%) and the DPG in mumol/gHb. Both factors exert a highly significant effect (p less than 0.001) on the P50, according to the following equation: P50 = 0.35 DPG +0.26 P(i) + 18.92 (r = 0.73). Our data are important in two points. First it is useful to add inorganic phosphates to the treatment of patients with severe ketoacidosis in order to enhance their tissue oxygenation. Second they recall that the ODC is not only determined by the classical effects of temperature, pH and DPG but also by inorganic anions, like phosphates as described by Benesh and Benesh in their pioneering work.

2,3-Diphosphoglycerate↗
PubMed1992

[The effect of inhaled salbutamol on pulmonary gas exchange in patients with chronic obstructive bronchopneumopathy].

The aim of this study is to establish whether or not the inhalation of a puff of salbutamol (Ventoline, 100 micrograms) could induce hypoxemia. Twenty-five chronic obstructive pulmonary disease (COPD) patients were investigated. In a first group of 20 patients arterial blood gases and related indices were measured before and 5, 10, 30, 60 and 90 minutes after inhalation of salbutamol. The oxyhemoglobin dissociation curve was traced before and 90 minutes after the drug intake. Except in two subjects in whom salbutamol dramatically improves arterial blood gases, the drug had no effect on the investigated parameters. It is concluded that salbutamol does not affect the blood gases in COPD patients. In this respect the behaviour of COPD patients differs from that of asthmatics in whom salbutamol generally induced hypoxemia.

Administration, Inhalation↗
PubMed1990

Paradoxical evolution of arterial blood gases during exercise in patients with chronic obstructive bronchitis.

In more than a thousand chronic obstructive lung disease (COLD) patients we have observed in six cases, that exercise-induced hypercapnia was accompanied by a concomitant improvement in arterial oxygen tension (PaO2) and a decrease in the alveolo-arterial O2. This behaviour was not due to technical errors. We explained the increase in PaO2 during exercise by three nonmutually exclusive mechanisms: 1) an increase in the respiratory quotient; 2) the exercise induced increase in alveolar ventilation, although inadequate to match the increase in CO2 production, would be redistributed to previously poorly ventilated regions of the lung, these regions therefore receiving enough oxygen to arterialize the blood flowing through the alveolar capillaries; 3) alternatively, perfusion would be redistributed in a more efficient way during exercise, so that even in the presence of hypoventilation, oxygenation would be improved.

Aged↗
PubMed1989

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.

Adult↗
PubMed1989

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

The inotropic agents, dopamine (DP) and dobutamine (DB), both decrease PaO2, probably by a redistribution of the VA/Q ratio. The aim of this study was to assess the effect of both drugs on the VA/Q ratio, using the multiple inert gas elimination method. Ten artificially ventilated patients (eight males), aged 45-74 years were investigated. Blood gases, cardiac output and concentrations of inert gases were measured before and 30 min after infusion of DB or DP. DP and DB were administered alternatively at a rate of 5 micrograms.k-1 min-1. The decrease in PaO2 was significantly greater with DP (12 +/- 9 torr) than with DB (7 +/- 9 torr) (P less than 0.01). Both drugs similarly increased cardiac output: +2.61.min-1 +/- 1.4 for DP and 2.21.min-1 +/- 1.5 for DB. Both DP and DB significantly (P less than 0.01) increased the perfusion of alveoli with VA/Q = 0 (+4 +/- 7% for DP and +3 +/- 7% for DB) and 0 less than VA/Q less than 0.1 (+11 +/- 8.5% for DP and +5.5 +/- 10.5% for DB) (no significant difference between the drugs). When shunt and "shunt-like" effect are considered together, there was a significantly greater increase in the amount of blood going to alveoli with a low VA/Q ratio with DP compared to DB. Both drugs decreased the perfusion of alveoli with 0.1 less than VA/Q less than 10, but the decrease was significantly less for DB than for DP (-15 +/- 6.5% for DP and -8.5 +/- 7% for DB, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

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.

Adolescent↗
PubMed1989

Pulmonary gas exchange during graded exercise in normal, sedentary, non-smoking subjects.

There is some discordance in the literature on the evolution of the alveolo-arterial oxygen tension difference (A-a)DO2 from rest (R) to graded exercise (E) in healthy subjects. For some authors and not for others (A-a)DO2 increased during exercise. In order to solve this problem we have examined 9 healthy, non-smoking sedentary students (5 males). In every subject PaO2 increased from rest to the highest level of exercise. (A-a)DO2 significantly increased from R and E1 to E2 and from E3 to E4. (A-a)DO2 at rest was 7.5 +/- 4.1 torr; at E1: 7.0 +/- 4.3 torr; at E2: 11.5 +/- 4.2 torr; at E3: 12.5 +/- 3.9 torr; and at E4: 16.5 +/- 4.3 torr. The oxyhemoglobin dissociation curve (ODC) was significantly shifted to the right from 53 to 92% saturation. This shift favours the liberation of O2 from hemoglobin to the tissues but cannot explain the evolution of (A-a)DO2. We believe that the increase in (A-a)DO2 is due to an increased maldistribution of the ventilation-perfusion ratio.

Adult↗
PubMed1988

Oxygen transport properties of blood in two different bovine breeds.

1. The whole oxygen dissociation curve of oxyhemoglobin has been determined in double-muscled cattle of the Belgian White Blue breed and in Friesian cattle of different body weight. 2. In calves, P50 values are low and DPG level is high (4-20 mumol/g Hb). 3. P50 values of 25 +/- 1.4 mm Hg (mean +/- SD) and a level of DPG less than 1.5 mumol/g Hb have been found in animals weighing more than 80 kg. 4. Effects of temperature and pH on the oxygen dissociation curve have been measured at all levels of saturation. The temperature coefficient (dlog P50/dT) and the Bohr effect expressed as dlog P50/dpH were 0.017 and -0.40, respectively. 5. Hematocrit, hemoglobin concentrations and oxygen capacity of hemoglobin have been measured. 6. No difference between both breeds has been observed. 7. These data can be used to correct measured values of oxygen tension for temperature and pH and to measure oxygen content of blood in cattle.

Animals↗
PubMed1986

[Determination of the standard oxyhemoglobin dissociation curve in horses. Effects of temperature, pH and diphosphoglycerate].

The equine blood oxyhemoglobin dissociation curve has been traced in its entirety in standard conditions and the effects of temperature, pH and 2,3-diphosphoglycerate on this curve have been measured. When compared to that of human blood, the curve showed a higher oxygen affinity of hemoglobin (23.8 +/- 0.8 versus 26.6 mm Hg). The effect of the pH, expressed by d log P50/dpH, was found to be identical in man and horse (-0.47). The effect of temperature, however, expressed by d log P50/dT, proved to be lower in the horse (0.016 versus 0.024). The P50 showed an increase of 1 mm Hg each time 2,3-diphosphoglycerate was experiencing an elevation of 4 mumol/gHb in the horse. The results obtained from this experiment are intended for the replacement of the values related to the human blood which have been found to be somewhat inadequate for the horse blood, when the data of blood gases are given in algorithms.

2,3-Diphosphoglycerate↗
PubMed1985

[Effect of almitrine administered by the oral route on levels of 2,3-diphosphoglycerate and on the affinity of hemoglobin for oxygen in healthy subjects].

Clinical and pharmacological studies have shown that almitrine increased arterial blood oxygen partial pressure (PaO2) and tissular oxygenation. We have verified whether this drug could also increase the 2,3 diphosphoglycerate (DPG) level and so modify the oxyhemoglobin dissociation curve (ODC). Determinations performed 3 hours and 5 days after daily oral administration (1,5 mg/kg) of the drug showed no alterations of DPG and ODC in normal subjects. The presence of almitrine does not explain the observed PaO2 increase by means of a direct effect on the hemoglobin oxygen affinity. However, one cannot exclude almitrine long term effect; indeed, after 15 days, DPG levels and Hill coefficient increased significantly (p less than 0.05) but no the P50 (respectively + 1,5 mumole/gHb; +0.1 and 26.0 vs 26.5 mmHg).

2,3-Diphosphoglycerate↗
PubMed1985

Assessment of a bubble tonometer as a quality control system for blood gas analyzers (PO2 and PCO2).

A blood gas tonometer device, comprising an accurate gas mixer (Corning 192) associated with a dual channel bubble tonometer (Corning 184) was tested for reliability, accuracy and ease of use as a quality control system for pO2 and PCO2 blood gas analyzers. From our results it is apparent that this system can be used instead of older and more bulky tonometry devices, gas mixing systems or cylinders of fixed composition.

Blood Gas Analysis↗
PubMed1976

Computer processing of oxygen dissociation curves.

Oxygen dissociation curves (ODC) plotted by a semi-automatic analyzer are subsequently processed by a digital computer. This computer processing provides a complete determination of the ODC, hence offering more information than the single P50 generally used. The programs consist of three successive modules each with a higher degree of sophistication in the processing. The mass handling of the curves is also described.

Computers↗