Is goal-directed fluid therapy based on dynamic variables alone sufficient to improve clinical outcomes among patients undergoing surgery? A meta-analysis.

BACKGROUND: Whether goal-directed fluid therapy based on dynamic predictors of fluid responsiveness (GDFTdyn) alone improves clinical outcomes in comparison with standard fluid therapy among patients undergoing surgery remains unclear. METHODS: PubMed, EMBASE, the Cochrane Library and ClinicalTrials.gov were searched for relevant studies. Studies comparing the effects of GDFTdyn with that of standard fluid therapy on clinical outcomes among adult patients undergoing surgery were considered eligible. Two analyses were performed separately: GDFTdyn alone versus standard fluid therapy and GDFTdyn with other optimization goals versus standard fluid therapy. The primary outcomes were short-term mortality and overall morbidity, while the secondary outcomes were serum lactate concentration, organ-specific morbidity, and length of stay in the intensive care unit (ICU) and in hospital. RESULTS: We included 37 studies with 2910 patients. Although GDFTdyn alone lowered serum lactate concentration (mean difference (MD) - 0.21 mmol/L, 95% confidence interval (CI) (- 0.39, - 0.03), P = 0.02), no significant difference was found between groups in short-term mortality (odds ratio (OR) 0.85, 95% CI (0.32, 2.24), P = 0.74), overall morbidity (OR 1.03, 95% CI (0.31, 3.37), P = 0.97), organ-specific morbidity, or length of stay in the ICU and in hospital. Analysis of trials involving the combination of GDFTdyn and other optimization goals (mainly cardiac output (CO) or cardiac index (CIx)) showed a significant reduction in short-term mortality (OR 0.45, 95% CI (0.24, 0.85), P = 0.01), overall morbidity (OR 0.41, 95% CI (0.28, 0.58), P < 0.00001), serum lactate concentration (MD - 0.60 mmol/L, 95% CI (- 1.04, - 0.15), P = 0.009), cardiopulmonary complications (cardiac arrhythmia (OR 0.58, 95% CI (0.37, 0.92), P = 0.02), myocardial infarction (OR 0.35, 95% CI (0.16, 0.76), P = 0.008), heart failure/cardiovascular dysfunction (OR 0.31, 95% CI (0.14, 0.67), P = 0.003), acute lung injury/acute respiratory distress syndrome (OR 0.13, 95% CI (0.02, 0.74), P = 0.02), pneumonia (OR 0.4, 95% CI (0.24, 0.65), P = 0.0002)), length of stay in the ICU (MD - 0.77 days, 95% CI (- 1.07, - 0.46), P < 0.00001) and in hospital (MD - 1.18 days, 95% CI (- 1.90, - 0.46), P = 0.001). CONCLUSIONS: It was not the optimization of fluid responsiveness by GDFTdyn alone but rather the optimization of tissue and organ perfusion by GDFTdyn and other optimization goals that benefited patients undergoing surgery. Patients managed with the combination of GDFTdyn and CO/CI goals might derive most benefit.