Brain damage and mortality in dogs following pulsatile and non-pulsatile blood flows in extracorporeal circulation.

In a series of 20 dog experiments, total cardiac bypass was followed by a high rate of mortality during the first 12 postoperative hours. Only five dogs survived for one week, but a further three dogs were perfuse-fixed after shorter periods of survival. All dogs developed pulmonary alveolar haemorrhages and seven of the eight perfuse-fixed brains exhibited brain damage. Diffuse nerve cell changes were found in the brains of dogs subjected to non-pulsatile blood flow. Focal brain lesions were found following both pulsatile and non-pulsatile blood flows. The lesions varied from staining pallor and rarefaction of the neuropil to total nerve cell loss and glial infiltration depending upon the duration of survival. When considered in conjunction with a previous series of experiments, these results show that the diffuse nerve cell changes associated with roller pump perfusions can be avoided by using a new pulsatile pump, but focal brain damage was not eliminated, and lung damage and mortality were not reduced.