Detecting if change in end-tidal carbon dioxide signifies change in cardiac output for the prediction of fluid responsiveness in patients undergoing major abdominal oncosurgery: An observational study
Shreyas Arun Chawathey, Sohan Lal Solanki, Jigeeshu Vasishtha DivatiaABSTRACT
Background and Aims:
Changes in end-tidal carbon dioxide (ΔETCO 2 ) have been proposed as a predictor of fluid responsiveness, but the available evidence remains inconsistent. We evaluated the ability of ΔETCO 2 to predict a ≥10% increase in cardiac index (ΔCI) following administration of a 4 mL/kg crystalloid bolus in patients undergoing major abdominal surgery.
Methods:
We conducted a prospective study in 22 adults undergoing major abdominal surgery between April 2022 and January 2023. Cardiac output and stroke volume were monitored using the FloTrac™ system with a Vigileo or EV1000 monitor. Patients were mechanically ventilated with a tidal volume of 8 mL/kg predicted body weight and a respiratory rate of 12–16 breaths/min. An intravenous bolus of Ringer’s lactate (4 mL/kg actual body weight over 10 minutes) was administered when haemodynamic parameters suggested hypovolaemia. Patients with a ΔCI ≥10% were classified as fluid responders, with ΔCI serving as the reference standard. ΔETCO 2 was evaluated against changes in stroke volume index (ΔSVI) and compared with pulse pressure variation (PPV) and stroke volume variation (SVV). Diagnostic performance was assessed using the area under the receiver operating characteristic (AUROC) curve.
Results:
ΔETCO
2
moderately predicted fluid responsiveness, with an AUROC of 0.823 [95% confidence interval (CI): 0.688–0.955] at a threshold of 1.5 mmHg (Youden index: 0.588,
Conclusion:
ΔETCO 2 may be a useful marker of fluid responsiveness after a fluid challenge.