Effect of Cardiorespiratory Changes on Carotid Flow Time During Lung Resection Surgery

Cardiorespiratory changes during lung resection surgery, even though generally well tolerated, may lead to hemodynamic compromise, reducing venous return to the heart and hence cardiac output. Carotid corrected flow time is widely regarded as non-invasive index of preload status, yet its dynamic relationship with cardiac output, especially in surgical population is not well-studied. Understanding how cardiorespiratory changes affect carotid flow time in anesthesized patients remains limited. This study investigates corrected carotid flow time response to anesthesia, lateral position, one-lung ventilation, open chest, capnothorax, lung recruitment and volume expansion, hypothesizing that cFT declines in association with CO reduction during lung resection. The secondary interest of the study is to test whether carotid flow time and its recruitment-induced change can adequately predict fluid response during one-lung ventilation. In addition, the baseline preoperative carotid flow time and its position-induced change are studied as potential predictors of hemodynamic tolerance to lung recruitment and fluid response, respectively. Finally, the purpose of this study is to see if cardiorespiratory changes and volume expansion affect cerebral blood volume during lung resection surgery.