Invited commentary

Does a conservative fluid management strategy in the perioperative management of lung resection patients reduce the risk of acute lung injury?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether a conservative fluid management strategy in the perioperative management of lung resection patients is associated with a reduced incidence of postoperative acute lung injury (PALI) and/or acute respiratory distress syndrome (ARDS) in the recovery period. Sixty-seven papers were found using the reported search, of which 13 level III and 1 level IV evidence studies represented the best evidence to answer the question. Two retrospective case-control studies demonstrated a direct association between liberal fluid intake and the incidence of PALI/ARDS following lung resection on multivariate analysis (MVA) with odds ratios (ORs) of 1.42 (95% CI 1.09-4.32, P = 0.011) and 2.91 (1.9-7.4, P = 0.001). In non-PALI/ARDS cases, the mean intraoperative fluid infusion volume was significantly less [1.22 l (1.17-1.26) vs 1.68 l (1.46-1.9) P = 0.005], the fluid balance over the first 24 postoperative hours was significantly less [1.52 l positive (1.44-1.60) vs 2.0 l positive (1.6-2.4) P = 0.026] and cumulated intra- and postoperative fluid infusion was significantly less [2.0 ml/kg/h (1.7-2.3) vs 2.6 ml/kg/h (2.3-2.9) P = 0.003]. These data show that the difference between fluid regimes associated with an increased incidence of PALI/ARDS (i.e. 'liberal') and those which are not (i.e. 'conservative') is narrow but significant. However, this does not prove a causative role for liberal fluid in the multifactorial development of PALI/ARDS. On this best evidence, we recommend intra- and postoperative maintenance fluid to be administered at 1-2 ml/kg/h and that a positive fluid balance of 1.5 l should not be exceeded in the perioperative period with caution being exercised with regard to the adequacy of oxygen delivery. If the fluid balance exceeds this threshold, a high index of suspicion for PALI/ARDS should be adopted and escalation of the level of care should be considered. If a patient develops signs of hypoperfusion after these thresholds are exceeded, inotropic/vasopressor support should be considered.