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Hemoglobin oxygen affinity in patients suffering from arterial occlusive disease of the legs
K M Braumann1, W Kleemann, U Martens
1Abteilung Sport- und Arbeitsphysiologie, Hochschule Hannover.
Insights
Arterial occlusive disease (AOD) patients exhibit altered hemoglobin oxygen affinity due to smoking-induced carboxyhemoglobin (COHb). This impacts oxygen delivery, potentially affecting tissue oxygenation in AOD.
Area of Science:
- Physiology
- Cardiovascular Medicine
- Biochemistry
Background:
- Arterial occlusive disease (AOD) affects peripheral circulation.
- Hemoglobin's oxygen affinity is crucial for oxygen transport.
- Smoking is a common risk factor for AOD and affects blood parameters.
Purpose of the Study:
- To investigate hemoglobin oxygen affinity in patients with leg arterial occlusive disease (AOD).
- To compare these parameters with healthy controls.
- To understand the influence of smoking and potential metabolic factors on oxygen transport in AOD.
Main Methods:
- Blood samples from 12 male AOD patients and healthy controls were analyzed.
- Hemoglobin oxygen affinity parameters, including oxygen dissociation curve (ODC), P50, and Bohr coefficients, were measured.
- Carboxyhemoglobin (COHb) and 2,3-diphosphoglycerate levels were determined.
Main Results:
- AOD patients, particularly smokers, showed elevated COHb levels, causing a leftward shift in the ODC.
- The half-saturation pressure (P50) was initially lower in AOD patients but normalized after COHb correction.
- Corrected ODC steepness (Hill's 'n') and Bohr coefficients (BCLac) were significantly different in AOD patients compared to controls, indicating altered oxygen binding.
- Elevated 2,3-diphosphoglycerate was observed, but did not fully compensate for COHb effects.
Conclusions:
- Smoking-induced COHb significantly alters hemoglobin oxygen affinity in AOD patients.
- AOD is associated with intrinsic changes in hemoglobin oxygen binding characteristics beyond COHb effects.
- Factors such as reduced erythrocyte age or metabolic byproducts may contribute to these alterations, impacting oxygen delivery in AOD.
Abstract:
Parameters characterizing the hemoglobin oxygen affinity were determined in blood of 12 male patients suffering from arterial occlusive disease (AOD) of the legs and compared with data obtained earlier from healthy human subjects (controls). Due to a COHb content of 4.8% +/- 2.2% in the cigarette-smoking AOD patients, the standard oxygen dissociation curve (ODC) was left-shifted, the half-saturation pressure (P50) amounted to 24.8 +/- 1.7 mmHg (3.30 +/- 0.23 kPa), although the 2,3-diphosphoglycerate concentration was increased to 15.3 +/- 1.7 mumol/g Hb. Correcting the effects of elevated COHb shifts the P50 to 26.3 mmHg (3.5 kPa) and increases the steepness of the ODC (Hill's "n") from 2.79 +/- 0.27 to about 2.99, which is significantly different from controls. The Bohr coefficients after acidification of blood with lactic acid (BCLac) show high values at low oxygen saturations of hemoglobin (-0.50 +/- 0.04 in AOD patients, -0.32 +/- 0.04 in controls; P less than 0.05 at 10% SO2). The cause of the alterations in hemoglobin oxygen affinity may be a reduced mean erythrocyte age, but also the influence of unknown factors generated, e.g., from anaerobic muscle metabolism in AOD.