Intraoperative fluid infusion rate during major pulmonary resection within an Enhanced Recovery After Surgery (ERAS) pathway: a retrospective cohort study

Background Intraoperative fluid management remains a debated component of Enhanced Recovery After Surgery (ERAS) pathways in thoracic surgery, with current guidelines recommending intraoperative infusion rates of 2–6 mL/kg/h despite limited high-quality evidence. We assessed whether the intraoperative fluid infusion rate was associated with prolonged length of stay (LOS) after major pulmonary resection. Methods We retrospectively reviewed 540 consecutive patients undergoing lobectomy, bi-lobectomy, or segmentectomy within a structured ERAS pathway, stratified by intraoperative infusion rate: G1 <4 mL/kg/h ( n= 76), G2 4–8 mL/kg/h ( n= 328, reference), and G3 >8 mL/kg/h ( n= 136). Multivariable logistic regression was performed to identify risk factors for prolonged LOS (>3 nights), before we conducted a generalised (multinomial) propensity score matching on four covariates (FEV1, blood loss, operating time, open surgical approach), yielding 59 matched triplets (177 patients). Results Prolonged LOS occurred in 206 patients (38.1%) and was independently associated with high intraoperative infusion rate (OR 2.86 [1.70–4.81]; p< 0.001). Propensity score matching confirmed a statistically significant association between prolonged LOS and infusion rate with 62.7% of G3 patients experiencing prolonged LOS compared to 42.4% in G2 and 39.0% in G1 ( p= 0.020). Conclusions Within a structured ERAS programme, high intraoperative fluid infusion rates (>8 mL/kg/h) were independently associated with prolonged length of stay after major pulmonary resection, in both multivariable and propensity-matched analyses. These findings suggest that high fluid infusion rates may be associated with longer hospital stay. Future efforts should prioritise prospective evaluation of individualised fluid strategies.