[Experimental model for hemodynamic and metabolic studies of extracorporeal circulation. Apropos of 14 cases]

The authors present an homogeneous and stable experimental model, the basic characteristics of which are: 14 extracorporeal bypass with: total bypass; normothermia; total haemodilution; beating heart; continuous flow in dogs anesthetised with chloralose. Three methods were employed: continuous recording of the venous lactate concentration; invasive electromagnetic measurement of the arterial blood flow; measurement of the tissular capillary blood flow with radioactive labelled microspheres. The statistic treatment of the informations gathered confirms that those experimentations took place in normothermia and constant: pH, venous and arterial pressure, cardiac pacing and arterial carotid blood flow. We noticed no modification of the body electrolytic repartition; blood gas variations do not modify haemodynamic conditions. Increase of the lactate concentration, as noticed in the literature, is in relation with a catecholamine hypersecretion and not with an anaerobic tissular function. Tissular capillary blood flow is constant if reported to cardiac index. This model will allow us to compare those results with new series where only one of the basic elements will be modified.