THE CARDIORESPIRATORY EFFECTS OF HAEMORRHAGE AND OVERTRANSFUSION IN DOGS BY

Changes in cardiorespiratory function resulting from haemorrhage and overtransfusion were measured in forty-seven dogs during controlled ventilation. In the animals bled to a mean arterial pressure of 70 mm Hg there were significant reductions in arterial Pco,, carbon dioxide output and oxygen consumption, cardiac output and total venous admixture. In the animals transfused to a mean central venous pressure of 15 mm Hg there was a significant fall in total thoracic compliance and arterial Po3 and significant increases in the alveolar-arterial Po, difference and carbon dioxide output. There have now been a number of reports which indicate that cardio-respiratory function during mechanical ventilation is affected by the pattern of ventilation employed. However, most of these studies have been performed on patients or animals with relatively normal respiratory and circulatory systems. In the present experiments an attempt has been made to study the effects o