Intraoperative Fluid Management Guided by Internal Jugular Vein on Postoperative Complications in Abdominal Surgeries

Overview

This study investigates the role of respiratory variation in the internal jugular vein as a tool for intraoperative fluid management during abdominal surgeries under general anesthesia. The purpose of this clinical trial is to reduce postoperative complications and improve patient outcomes through proper intraoperative fluid management. The main question it aims to answer is: Can intraoperative fluid management guided by the respiratory variation of the internal jugular vein during abdominal surgeries reduce postoperative complications? Research Hypothesis (Alternative Hypothesis): We hypothesize that fluid management guided by the respiratory variation of the internal jugular vein during abdominal surgeries can reduce postoperative complications. The patients will be divided into two groups and randomized to receive either intraoperative fluid therapy guided by the respiratory variation of the internal jugular vein or standard fluid therapy. Postoperative complications, length of hospital stay, total amount of fluid administered intraoperatively, use of vasopressors in both groups, and incidence of hypotensive episodes will be recorded.

Sonographic measurement of respiratory variation of IJV will be performed with a Philips CX50 ultrasound device (Philips Healthcare, Hamburg, Germany), equipped with a linear transducer. Respiratory variation of IJV will be measured by the same anesthesiologist with sufficient experience in ultrasound guided IJV cannulation. The anesthesiologist performing the ultrasound examinations will not be involved in this study and blinded to the hemodynamic parameters; a lead plate separated the monitor from the anesthesiologist and ultrasound device. The optimal short axis of the IJV will be obtained at the level of the cricoid cartilage by placement of the transducer perpendicular to the skin on the patient's neck in a transverse plane. The vein will be identified with color Doppler imaging as well as by compression. Ultrasound measurements will be performed on the left IJV, M-mode scan will be used to record the IJV diameter at the end of inspiration (IJVmax) and expiration (IJVmin) over an entire respiratory cycle. The images will be then frozen. The respiratory variation of IJV will be calculated with the following formula: IJV RV (%) = (IJVmax - IJVmin)/ (IJVmin) × 100%. The average values of IJVmax and IJVmin from three consecutive respiratory circles will be used in the analysis. The finding of a small-diameter IJV (\<1cm) and increased IJV RV (\>18) suggest low-volume states. Conversely, a large IJV diameter (\>2.1cm) and decreased IJV RV (\<18) will suggest a high-volume state.