Evaluation of Acute Respiratory Distress Syndrome in Participants Enrolled in the Protocolized Care for Early Septic Shock (ProCESS) Trial

Background: Sepsis is the most common etiology of acute respiratory distress syndrome (ARDS), and the latter, if severe, has mortality rate averaging 45%. The frequency of early septic shock-associated ARDS and the subsequent short-term mortality is poorly described.

Methods: We conducted an ancillary study of the Protocolized Care for Early Septic Shock (ProCESS) trial to determine the incidence of ARDS and to describe baseline characteristics and clinical outcomes for these participants with early septic shock presenting to the emergency departments of two ProCESS study sites. We applied the Berlin Criteria for ARDS, and for participants with PaO2/FiO2 (P/F) ≤ 300, with chest radiographs independently reviewed by two radiologists to determine consistency with criteria. Discordance between the radiologists was adjudicatedby a panel of pulmonary intensivists.

Results: Of 179 participants, 47 received invasive mechanical ventilation with P/F ≤ 300. After radiographic determination, ARDS incidence was 12.3% (22/179). Of the participants who developed ARDS, the median and mean P/F ratios were 122.1 and 122.9 mmHg, respectively. ARDS case severity frequencies were “mild” (5%, P/F 201-300) “moderate” (55%, P/F 100 - 200), or “severe” (41%, P/F <100), with corresponding mortality rates of 0%, 33%, 78%, respectively. After multivariable adjustment, ARDS development was associated with a 3.7-fold higher 60-day in-hospital mortality rate (95% confidence intervals [CIs]: 1.16-5.71), 4.86-fold longer ICU length-of-stay (LOS) (95% CI: 1.69- 8.04), and 4.86-fold longer hospital LOS (95% CI: 1.69- 8.04).

Conclusion: ARDS incidence in ED participants presenting with early septic shock is high. Compared to early septic shock participants without ARDS, participants with early septic shock who developed ARDS have a significantly higher mortality rate and both ICU and hospital LOS. Further investigations are needed to verify if our findings remain true.