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Determinants of systemic vascular resistance in children with congenital heart disease
Insights
Chronic changes in hemoglobin, oxygen saturation, and acid-base state affect systemic vascular resistance, similar to acute conditions. These factors remain significant predictors in patients with congenital heart disease.
Area of Science:
- Cardiovascular Physiology
- Pulmonary Hypertension Research
- Congenital Heart Disease
Background:
- Acute changes in systemic arterial oxygen saturation, hemoglobin concentration, and acid-base state are known to alter systemic vascular resistance.
- The persistence of these effects in chronic conditions remains largely uninvestigated.
Purpose of the Study:
- To determine if factors influencing systemic vascular resistance in acute states also affect it in chronic states.
- To investigate the relationship between hemoglobin concentration, systemic arterial oxygen saturation, and acid-base balance with systemic vascular resistance in individuals with congenital heart disease.
Main Methods:
- Systemic vascular resistance was measured in 195 subjects with congenital heart disease.
- Multiple regression analysis was employed to assess the predictive significance of hemoglobin concentration, systemic arterial pH, and oxygen saturation, while accounting for patient size.
Main Results:
- Hemoglobin concentration, systemic arterial pH (or non-respiratory pH), and systemic arterial oxygen saturation were all significantly and positively correlated with systemic vascular resistance (P < 0.025).
- These correlations remained significant even after adjusting for patient size.
Conclusions:
- The physiological mechanisms influencing systemic vascular resistance in acute conditions appear to remain functional in chronic states.
- Hemoglobin concentration, systemic arterial oxygen saturation, and acid-base status are significant determinants of systemic vascular resistance in the chronic setting, particularly in congenital heart disease.
Abstract:
It is well known on the basis of acute experiments that changes in systemic arterial oxygen saturation, haemoglobin concentration and acid-base state produce changes in systemic vascular resistance. However, it is not known whether the same changes occur in the chronic state. In order to investigate this problem, we measured systemic vascular resistance in a population in whom chronic changes in these variables are common, namely 195 subjects with congenital heart disease. The significance of these factors was assessed by their ability to predict systemic vascular resistance in a multiple regression equation which also took account of the size of the patient. No matter how the size of the patient was allowed for, haemoglobin concentration, systemic arterial pH (or non-respiratory pH) and systemic arterial oxygen saturation were significantly (P less than 0.025) and positively correlated with systemic vascular resistance. We conclude that, as far as these factors are concerned, the mechanisms operating in the acute state continue to function in the chronic state.