SW3Brauthwaite, M. A. (1975). Thorax, 30,[258][259][260][261]. Prevention of neurological damage during open-heart surgery. A previous study of neurological damage related to openheart surgery suggested that the onset of cardiopulmonary bypass is a time of particular hazard, and there is evidence that both microemboli from the extracorporeal circulation and inadequate cerebral perfusion may be contributory factors.Measures to eliminate or minimize these hazards have been introduced, and a clinical survey has been undertaken to evaluate their efficacy. There has been a very highly significant decrease in the incidence of neurological damage as judged by comparison with the results of a similar survey carried out before these measures were introduced.In spite of limitations imposed by differences in workload, perfusion techniques, and methods of data collection, it is concluded that the prophylactic measures have been responsible for the reduction in the incidence of neurological damage.A previous clinical survey, based upon the retrospective analysis of the case notes of 417 patients submitted to open-heart surgery during 1970, revealed an incidence of neurological damage of 192% (Branthwaite, 1972). Evidence derived by monitoring cerebral function with a heavily filtered electroencephalograph (Cerebral Function Monitor, Devices Ltd) suggested that the onset of perfusion is a time of particular hazard (Branthwaite, 1973). Microemboli from the extracorporeal apparatus, and inadequate cerebral perfusion caused by an abrupt change in the character and magnitude of the perfusing pressure, could contribute to these findings, and there is experimental and clinical evidence which suggests that both factors may be of importance (Stone et al., 1967;Hasbrouck and Rigor, 1969;Javid et al., 1969;Patterson and Kessler, 1969;Hill et al., 1970;Osborn et al., 1970;Tufo, Ostfeld, and Shekelle, 1970;Egeblad et al., 1972;Sanderson, Wright, and Sims, 1972;Branthwaite, 1974 (Figure) or dilatation of the pupils. A second survey was undertaken during 1973 to evaluate the efficacy of these measures. FIGURE Record obtained from the cerebral function monitor at the onset of perfusion in a 43-year-old woman with mild mitral stenosis and hypertension (160/100 mmHg). The arterial blood pressure fell to between 30 and 40 mmHg when the aorta was crossclamped, in spite of a flow of 80 ml/kg per minute from the oxygenator. The resulting cerebral depression was reversed rapidly by the administration of metaraminol (Aramine), and the patient regained consciousness after the operation without any evidence of neurological deficit. Paper speed-6 mm/min.
MATERIAL AND METHODSThe case notes of all patients submitted to openheart surgery during 1973 were inspected. The data were collected retrospectively to preserve 258 on 11 May 2018 by guest. Protected by copyright.