Comparison of balanced and unbalanced crystalloids as resuscitation fluid in patients treated for cardiogenic shock

Background The efficacy and safety of saline versus balanced crystalloid solutions in ICU-patients remains complicated by exceptionally heterogenous study population in past comparative studies. This study sought to compare saline and balanced crystalloids for fluid resuscitation in patients with cardiogenic shock with or without out-of-hospital cardiac arrest (OHCA). Methods We retrospectively analyzed 1032 propensity score matched patients with cardiogenic shock from the Munich University Hospital from 2010 to 2022. In 2018, default resuscitation fluid was changed from 0.9% saline to balanced crystalloids. The primary endpoint was defined as 30-day mortality rate. Results Patients in the saline group ( n = 516) had a similar 30-day mortality rate as patients treated with balanced crystalloids ( n = 516) (43.1% vs. 43.0%, p = 0.833), but a higher incidence of new onset renal replacement therapy (30.2% vs 22.7%, p = 0.007) and significantly higher doses of catecholamines. However, OHCA-patients with a lactate level higher than 7.4 mmol/L had a significantly lower 30-day mortality rate when treated with saline (58.6% vs. 79.3%, p = 0.013). In addition, use of balanced crystalloids was independently associated with a higher mortality in the multivariate cox regression analysis after OHCA (hazard ratio 1.43, confidence interval: 1.05–1.96, p = 0.024). Conclusions In patients with cardiogenic shock, use of balanced crystalloids was associated with a similar all-cause mortality at 30 days but a lower rate of new onset of renal replacement therapy. In the subgroup of patients after OHCA with severe shock, use of balanced crystalloids was associated with a higher mortality than saline. Trial registration : LMUshock registry (WHO International Clinical Trials Registry Platform Number DRKS00015860).