The ALT SHOCK criteria for respiratory failure in cardiogenic shock

Background and aims

Cardiogenic shock (CS) is frequently complicated by acute respiratory failure (ARF), yet no standardized definitions of ARF have been applied in this context. The Berlin definition for acute respiratory distress syndrome (ARDS) has shown predictive validity in critically ill patients but has not been tested in CS.

This study aimed to evaluate whether hypoxemia severity, as defined by the Berlin criteria, predicts outcomes in a large, prospective registry of CS patients with ARF.

Methods and Results

Patients requiring positive pressure mechanical ventilation-either non-invasive or invasive - within the AltShock-2 registry ( NCT04295252 ) were included. Demographic and clinical features were analyzed with a focus on Horowitz index along with the others ARDS Berline criteria adapted to the CS setting. Multivariable logistic regression and Cox proportional hazards models were used to identify predictors in-hospital mortality, including the others Berlin criteria adopted in CS population.

Out of 1056 enrolled patients, 476 with CS and ARF were analyzed. All-cause mortality significantly differed by RF severity: 29.9% (mild), 31.7% (moderate), and 40.5% (severe) (p = 0.043). Severe hypoxemia was independently associated with increased mortality at admission [adjusted HR 3.412 (95% CI 2.978–4.857)] and at 24 hours [adjusted HR 2.55 (1.164 – 3.872)] since hospitalization. Alongside, severity of lung congestion and etiologies were also independently associated with dismal outcome.

Conclusion

According to our results, severe hypoxemia acts as an outcome modifier and the integration of PaO2/FiO2 ratio should be considered as an additional parameter in the SCAI classification.

Clinical Trial Registration

Clinical Trials.gov https://clinicaltrials.gov/study/NCT04295252 NCT04295252