Effect of VExUS Score-Guided Intraoperative Goal-Directed Fluid Therapy on Postoperative Pulmonary Complications in Elderly Patients Undergoing McKeown Minimally Invasive Esophagectomy: A Randomized Controlled Trial

1. Background In China, esophageal cancer (EsC) is a common malignancy of the digestive tract, and surgery remains the primary treatment modality . Currently used esophageal tumor resection approaches include McKeown esophagectomy, Ivor Lewis esophagectomy, and Sweet esophagectomy, among others. Among these, thoracoscopic three-incision McKeown minimally invasive esophagectomy (McKeown MIE) offers advantages in lymph node dissection and is therefore one of the commonly used surgical approaches for esophageal cancer. Postoperative pulmonary complications (PPCs) are the most frequent type of complication following esophagectomy, accounting for 28.9%-50% of all complications , and have been demonstrated to be associated with in-hospital mortality , prolonged hospital stay, and increased medical costs .

With the implementation of enhanced recovery after surgery (ERAS) protocols, perioperative fluid management in esophageal cancer surgery has become increasingly important. Inappropriate perioperative fluid volume is an independent risk factor for lung injury . Veelo et al. emphasized that goal-directed hemodynamic therapy can significantly reduce the incidence of postoperative pneumonia . In the absence of continuous hemodynamic monitoring, total intraoperative fluid infusion exceeding 5000 mL should be avoided in patients without ongoing blood loss . Inappropriate intraoperative blood transfusion increases the incidence of PPCs, elevates postoperative mortality, and leads to poorer long-term prognosis due to higher tumor recurrence rates .

Therefore, perioperative fluid management is particularly critical in McKeown MIE. In patients undergoing this procedure, perioperative fluid overload can lead to: (a) increased capillary hydrostatic pressure, and (b) accumulation of excess fluid in the alveolar space, causing alveolar compression, collapse, and exudation, resulting in increased dead space ventilation and intrapulmonary shunt, which in turn induces pulmonary venous congestion and interstitial pulmonary edema. Conversely, inadequate fluid resuscitation may lead to insufficient organ perfusion, exacerbating organ injury such as acute kidney injury (AKI). The traditional "empiric fluid therapy" approach is gradually being replaced by goal-directed fluid therapy (GDFT). Thus, GDFT has become an important target for preventing PPCs in elderly patients undergoing McKeown MIE.

GDFT aims to optimize end-organ perfusion and improve tissue oxygen delivery through precise fluid administration, thereby reducing the risk of PPCs. Existing GDFT strategies include fluid therapy based on dynamic hemodynamic parameters (Vigileo-FloTrac™), central venous pressure (CVP)-guided fluid therapy , perfusion index-guided therapy, and transesophageal echocardiography (TEE)-guided fluid therapy. However, compared with the Venous Excess Ultrasound (VExUS) score, these monitoring modalities cannot accurately and real-time reflect overall venous congestion, nor can they provide integrated monitoring of the matching between venous return driving pressure and right ventricular function.

The VExUS score is an emerging bedside ultrasound-based volume quantification tool that evaluates important capacitance veins, including the inferior vena cava diameter, and the hepatic, portal, and renal veins. By comprehensively monitoring their vessel diameter, resistance indices, and Doppler waveforms, it provides a real-time, non-invasive, and direct reflection of the match between fluid therapy and patient status .