The predictive value of tidal volume challenge-induced hemodynamic changes for fluid responsiveness in patients...

Video-assisted thoracic surgery (VATS) relies on one-lung ventilation (OLV) to achieve optimal surgical conditions. However, the lung protective ventilation strategies commonly employed during OLV diminish the accuracy of traditional dynamic parameters in predicting fluid responsiveness. The tidal volume challenge (TVC) has been proposed to overcome this limitation, yet its effectiveness in OLV patients remains to be validated. In this study, we used LiDCO to evaluate TVC-induced changes in SVV(ΔSVV_TVC) and PPV(ΔPPV_TVC), and assessed their ability to predict fluid responsiveness in patients receiving lung-protective OLV during VATS.

All patients received OLV in lateral position after general anesthesia induction. Upon achieving hemodynamic stability, the study protocol was initiated. Hemodynamic and respiratory parameters, including heart rate, mean arterial pressure, stroke volume variation (SVV), pulse pressure variation (PPV), stroke volume index (SVI), cardiac index, peak inspiratory pressure, and dynamic lung compliance were recorded at four time points: before TVC (T₁, tidal volume 6 mL/kg), 1 min after TVC (T₂, tidal volume 8 mL/kg), 2 min after returning to baseline tidal volume (T₃, pre-fluid challenge), and after volume loading test (VLT, T₄). The VLT consisted of infusing 7 mL/kg hydroxyethyl starch over 20-30 min. ΔSVV_TVC and ΔPPV_TVC were calculated as changes from T₁ to T₂, and the fluid responsiveness was defined as stroke volume index ≥ 10% increase after VLT.

Among the 60 patients, 26 (43%) were fluid responders. ROC analysis showed that the area under the curve (AUC) of ΔSVV_TVC for predicting fluid responsiveness was 0.83 (95% CI, 0.71-0.91), with an optimal cutoff value of > 2%, sensitivity of 77%, specificity of 76%, and a gray zone range of 1%-3% encompassing 23 patients (38%). For ΔPPV_TVC, the AUC was 0.86 (95% CI, 0.74-0.93), with a cutoff of > 3%, sensitivity of 85%, specificity of 80%, and a gray zone of 2%-4% including 13 patients (22%).Subgroup analysis revealed no significant difference in the predictive AUC values of ΔSVV_TVC or ΔPPV_TVC between the left and right lateral decubitus positions.

Tidal volume challenge -induced changes in SVV and PPV effectively predict fluid responsiveness in OLV patients, and their predictive performance is not influenced by patient position.

This trial was registered with Chinese Clinical Trial Registry, ChiCTR2300075285, August 31, 2023.