Fluid balance and outcome in cardiac arrest patients admitted to intensive care unit

Although shock following cardiac arrest is common and contributes significantly to mortality, the influence of the modalities used to manage the hemodynamic situation, particularly with regard to fluid balance, remains unclear. We evaluated the association between positive fluid balance and outcome after out-of-hospital cardiac arrest (OHCA).

We conducted a multicenter study from August 2020 to June 2022, which consecutively enrolled adult OHCA patients in 17 intensive care units. The primary endpoint was 90-day survival. Multivariate Cox analysis, propensity score matching and landmark analysis were performed, along with several sensitivity analyses.

Of the 816 patients included in our study, 74% had a positive fluid balance, and 291 of 816 patients (36%) were alive at 90-day. A positive fluid balance was associated with mortality after adjusted multivariate analysis (HR = 1.8 [1.3 - 2.3], p < 0.001), after propensity score matching (n = 193 matched patient pairs, HR = 1.6 [1.1 - 2.1], p = 0.005) and after landmark analysis. We reported a dose-dependent association between fluid balance and mortality. Patients with a positive fluid balance were more likely to need renal replacement therapy (10% vs. 2%, p = 0.001) and had a lower minimum P_aO₂/F_iO₂ ratio in the first seven days (158 vs. 180, p < 0.001).

After cardiac arrest, a positive fluid balance is consistently associated with a worse outcome. Pending further data, a restrictive fluid therapy strategy may be beneficial in post-OHCA patients.

ClinicalTrial.gov cohort AfterROSC-1 NCT04167891 registered November 13th, 2019, ethics committees 2019-A01378-49 and CPP-SMIV 190901.