Fluid balance after cardiac arrest: Any impact on outcome? Insights from the MIMIC IV database

Fluid balance is closely associated with outcomes in septic shock. Post-cardiac arrest (CA) shock, which accounts for one-third of deaths after CA, shares many pathophysiological features with sepsis. However, the impact of fluid balance has not been analyzed in this setting. This study aimed to assess the impact of fluid balance on mortality during post-CA shock.

This retrospective study used the Medical Information Mart for Intensive Care (MIMIC)-IV database. Fluid balance was quantified during the first 72 h. Multivariate logistic-regression analysis identified factors associated with early (by day 3) mortality.

Among the 1800 patients resuscitated from CA, 868 (68 %) developed post-CA shock. Of these, 801 were analyzed; 334 (42 %) died within 3 days. Early non-survivors had a higher median fluid balance (+3289 mL [25th; 75th IQR + 502; +5806]) than early survivors (+930 mL [-2677; +4353]) (P < 0.001). Positive fluid balance independently predicted death by day 3 (OR 2.23, 95 % CI [1.29; 3.14]; P = 0.005). Mortality increased significantly with increasing fluid balance, especially from 1000 mL and upwards (OR 4.11, 95 % CI [2.32; 2.47]; P < 0.001). Other factors independently associated with early mortality included age >66 years, maximum catecholamines dose, and peak serum lactate.

These findings confirm that fluid balance is associated with early mortality during post-CA shock.