Tendency Toward Hypotension in Left Lateral Recumbency

WITH THE aim of achieving a better insight into the pathogenesis of the cardiovascular accidents which still occur so frequently during surgical operations and often remain unexplained even on autopsy I observed, in 1949, a series of patients during thoracic surgical procedures. 1 Among the causes of cardiovascular complications noted, there was a shock-like state which in certain patients recurred several times when renewed attempts were made on different days to perform the intended operation or when different stages of a thoracoplasty were performed. Immediately or soon after the patient was turned to the lateral recumbent position, a pronounced fall in blood pressure was registered, and sometimes no blood-pressure readings could be obtained for certain periods. Yet, whenever the patient was returned to the supine or sitting position, the normal preoperative pressure readings were obtained immediately or a few minutes later (see Fig. 1). This positional complication occurred before the