Estudio de validación de los parámetros dinámicos de respuesta a fluidos, variación de volumen sistólico (VVS) y variación de presión de pulso (VPP), durante la cirugía de resección pulmonar

Introduction: In lung resection surgery, restrictive fluid therapy is recommended due to high risk of post-resection acute lung injury attributed to the liberal use of fluids. However, this therapy can lead to vascular hypoperfusion and therefore increased morbidity and mortality. Intraoperative fluid therapy should be individualized for each patient, adjusting the supply or restriction of fluids in order to optimize cardiac output and avoid vital organs injury. Goal-guided fluid therapy enables this fluid individualization to be performed by analyzing SVV and PPV parameters. The main objective of this study is the validation of SVV and PPV in lung resection surgery, where there are surgical and ventilatory conditions that modify intrathoracic pressures. Material and method: We included 25 patients scheduled for lung resection surgery, monitored using the PiCCO system. We analyze what changes occur in SVV and PPV during lateral position and one-lung ventilation with tidal volume of 6 ml/kg and open chest. We performed a mixed linear regression analysis of the hemodynamic variables at different times of surgery. 250 ml crystalloid loads were administered if IC <2.5 l/min/m2, SVV >8% and/or PPV >10%. We classified the patients into responders (if CI >10% and/or VSI >10% after volume loading) and non-responders. We evaluated the diagnostic efficacy and the ideal cut-off point for SVV and PPV using ROC curves. Data on PaO2/FIO2, ELWI, pre and postoperative creatinine were collected at 24 hours after the intervention to detect pulmonary and renal complications. Results: One-lung ventilation during lateral decubitus produces a 27% decrease in PPV (p = 0.01); 95% CI [-6.23; -0.55] and 20% in VVS (p = 0.07); 95% CI [-5.16; 0.15]. The hemodynamic variables of contractility and preload (IC, VSI, dPmax, GEDI, GEF and CFI) do not show clinically relevant changes in relation to intrathoracic pressure changes. In the analysis of ROC curves for SVV and PPV, a discriminatory value of patients responding to a volume load was not reached from those who are not (AUC for SVV = 0.47; AUC for PPV = 0.50), despite having decreased the SVV and PPV threshold value during lung resection surgery. Conclusions: One-lung ventilation with VT 6 ml/kg and lateral position, generates a 27% decrease in PPV and 20% in SVV. Despite taking into account this decrease, the SVV and PPV parameters were not shown to be useful in diagnosing a response to fluids during lung resection surgery. The ELWI value was mostly kept below 15 ml/kg, without presenting other criteria for pulmonary edema. The ELWI value is proposed as a good parameter for monitoring pulmonary edema during intraoperative management of goal-guided fluid therapy in lung resection surgery, thus avoiding a supply of fluids that could cause lung damage. None of the study patients were diagnosed with stage I acute kidney injury according to the AKIN criteria.