In-hospital emergencies versus out-of-hospital emergencies admitted to ICU: is the outcome different? An observational study

Background: Rapid Response Systems (RRS) are now commonly implemented throughout hospital health systems to manage in-hospital emergencies (IHE). There is limited data on characteristics and outcomes of such patients admitted to an intensive care unit (ICU). The goal was to determine whether the hospital mortality of ICU patients was different depending on their admission pathway: in-hospital via rapid response teams (RRT), or out-of-hospital emergencies (OHE) via prehospital emergency medical systems. Results: Out of 422 ICU admissions (Timone University Hospital ICU), 241 patients were retrospectively (2019-2020) included: 74 IHE versus 167 OHE. In-hospital mortality rates did not differ between both cohorts (n = 31(42%) vs. 63(39%) respectively, NS). IHE patients were older and had more comorbidities (immunosuppression and ongoing malignancy). OHE patients had more severe organ failures at presentation with more frequent mechanical ventilation support. Independent global hospital mortality risk factors were ongoing malignancy (OR = 10.4 [2.7-40], p < 0.001), SAPS II (OR = 1.05 [1.03-1.08], p < 0.0001) and SOFA scores (OR = 1.14 [1.01-1.3], p < 0.05), hemorrhagic stroke as admission diagnosis (OR = 8.4 [2.7-26], p < 0.001), and arterial lactate on arrival (OR = 1.11 [1.03-1.2], p < 0.01). Conclusion: This study provides a thorough and comprehensive analysis of characteristics and outcomes of ICU admissions following a mature rapid response activation system, compared to the “conventional” out-of-hospital admission pathway. Despite the more vulnerable background of IHE patients, hospital mortality does not differ, supporting the use of early RRS to identify deteriorating ward patients. Take-home message: Hospital mortality does not differ between in-hospital emergencies admitted to intensive care unit and conventional out-of-hospital admissions, supporting the use of early rapid response systems and the importance of early intensive care unit admission.