Development and validation of a clinico-biological score to predict outcomes in patients with drowning-associated cardiac arrest

Background: While several scoring systems have been developed to predict short-term outcome in out-of-hospital cardiac arrest patients, there is currently no dedicated prognostic tool for drowning-associated cardiac arrest (DACA) patients.

Methods: Patients experiencing DACA from two retrospective multicenter cohorts of drowning patients were included in the present study. Among the patients from the development cohort, risk-factors for day-28 mortality were assessed by logistic regression. A prediction score was conceived and assessed in patients from the validation cohort.

Results: Among the 103 included patients from the development cohort, the day-28 mortality rate reached 51% (53/103). Identified independent early risk-factors for day-28 mortality included cardiopulmonary resuscitation duration longer than 20 min (OR 6.40 [95% CI 1.88-23.32]; p = 0.003), temperature at Intensive Care Unit admission <34 °C (OR 8.84 [95% CI 2.66-32.92]; p < 0.001), need for invasive mechanical ventilation (OR 6.83 [95% CI 1.47-40.87]; p = 0.02) and lactate concentration > 7 mmol/L (OR 3.56 [95% CI 1.01-13.07]; p = 0.04). The Area Under the ROC Curve (AUC) of the developed score based on those variables reached 0.91 (95% CI, 0.86-0.97). The optimal cut-off for predicting poor outcomes was 4 points with a sensitivity of 92% (95% CI, 82-98%), a specificity of 82% (95% CI, 67-91%), a positive predictive value (PPV) of 84% (95% CI, 72-95%) and a negative predictive value (NPV) of 91% (95% CI, 79-96%). The assessment of this score on the validation cohort of 81 patients exhibited an AUC of 0.82. Using the same 4 points threshold, sensitivity, specificity, PPV and NPV values of the validation cohort were: 81%, 67%, 72% and 77%, respectively.

Conclusion: In patients suffering from drowning induced initial cardiac arrest admitted to ICU with a DACA score ≥ 4, the likelihood of survival at day-28 is significantly lower. Prospective validation of the DACA score and assessment of its usefulness are warranted in the future.