| Abstrakt: |
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 < 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. [ABSTRACT FROM PUBLISHER] |
