Fluid infusion prior to intubation or anesthesia: A meta-analysis of randomized controlled trials

Background: The results of current randomized controlled trials (RCTs) vary regarding the effectiveness of rehydration prior to anesthesia induction. Our objective was to determine the effectiveness of pre-induction rehydration in patients undergoing tracheal intubation or surgical procedures. Methods: This meta-analysis followed PRISMA guidelines and was registered in the INPLASY database (registration number: INPLASY2022100099). Two reviewers independently searched PubMed, Embase, The Cochrane Database of Systematic Reviews, and Clinical Trials databases until October 2022, without any restrictions on date. Any randomized controlled trial investigating the administration of intravenous fluids to patients undergoing tracheal intubation or pre-surgical anesthesia induction was considered eligible. Exclusion criteria were applied to exclude certain literature. Data were analyzed using RevMan (5.4.1) software after independent extraction. The primary objective of this study was to determine if intravenous rehydration could reduce the occurrence of hypotensive events and the use of vasoactive drugs following anesthesia induction. Results: This meta-analysis included seven studies with a total of 2850 patients, including 1430 patients who received rehydration and 1420 control patients. Patients who received early rehydration had a lower incidence of hypotensive events compared to those who did not (RR 0.78, 95% CI 0.66-0.92, P = 0.004). No heterogeneity was observed (p = 0.31, I2 = 16%). However, subgroup analysis showed that rehydration before tracheal intubation did not reduce hypotensive events in critically ill patients (RR 0.99, 95% CI 0.61-1.60, P = 0.96). There were no significant differences in the use of vasoactive medications between the two study groups (RR 0.96, 95% CI 0.80-1.16, P = 0.69). No heterogeneity was observed (p = 0.26, I2 = 23%). The funnel plot indicated no evidence of publication bias. Conclusions: Pre-induction rehydration can reduce the occurrence of hypotensive events, but only in pre-surgical patients, and does not decrease the use of vasoactive medications.