Orthostatic function and the cardiovascular response to early mobilization after breast cancer surgery

Abstract

Early postoperative mobilization is essential for an enhanced recovery, but it can be hindered by orthostatic intolerance, characterized by signs of cerebral hypoperfusion, such as dizziness, nausea, vomiting, and ultimately syncope. Orthostatic intolerance is frequent after major surgical procedures, because of an attenuated cardiovascular response, but the cardiovascular response and the incidence of orthostatic intolerance after minor procedures have not been clarified. We investigated the cardiovascular response and the incidence of orthostatic intolerance during early mobilization after breast cancer surgery. Twenty-four women undergoing breast cancer surgery performed a mobilization procedure before and 30 min after surgery, with measurement of arterial pressure, stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) (Modelflow), besides evaluation of cerebral and muscle oxygenation (near-infrared spectroscopy) and recording of symptoms of orthostatic intolerance. There were no differences in the cardiovascular response and tissue oxygenation before and 30 min after surgery (P>0.05). Upon mobilization, systolic arterial pressure, SV, CO, and cerebral and muscle oxygenation decreased (P<0.05), whereas heart rate increased without change in TPR. After surgery, one patient (4%) experienced orthostatic intolerance, and one patient could not complete the mobilization procedure after surgery because of sedation. With the used regimen of anaesthesia, pain treatment, and fluid therapy, orthostatic intolerance is infrequent 30 min after breast cancer surgery, apparently because the cardiovascular response and tissue oxygenation are preserved. Future studies assessing orthostatic intolerance should focus on larger surgical procedures and apply interventions that potentially maintain the cardiovascular response to mobilization.