A systematic review and meta-analysis published in Crit_Care reports a systematic decrease in hemoglobin concentration after rapid fluid administration, raising uncertainty about the effects of fluid on oxygen delivery in fluid non-responders.
Data analysis
The primary analysis was the mean difference with 95% confidence interval in Hb before and after rapid fluid administration . A secondary analysis was the mean difference in DO. Anticipating a high degree of heterogeneity inherent to the differences between different protocols, we used a random-effects model according to the Hartung-Knapp method. We assessed heterogeneity across studies using thestatistic.
For each trial, the risk of bias was evaluated independently by three authors using the Cochrane risk of bias tools to evaluate the quality of included randomized controlled trials and non-RCTs . A fourth author resolved any disagreements. Certainty of evidence was assessed by the Grading of Recommendations Assessment, Development and Evaluation tool.
Studies in which the mean ∆Hb with its standard deviation was reported or could be calculated were included in the meta-analysis. If a study presented data in different subgroups of patients each cohort was considered separately for the meta-analysis [The results of studies grouped according to pre-specified study-level characteristics and presence of fluid responsiveness were compared using a stratified meta-analysis or random-effects meta-regression.
All analyses were conducted using Stata software, version 17 with meta command. Statistical significance was considered at the 5% level.