Systemic Inflammatory Response Syndrome (SIRS) After Extracorporeal Membrane Oxygenation (ECMO): Fact or Fiction

Karthik Thangappan, BS; Nicholas Cavarocchi, MD; Michael Baram, MD; Brandi Thoma, PharmD; Hitoshi Hirose, MD

PURPOSE: Fever and leukocytosis are commonly observed after ECMO decannulation, and it is difficult to differentiate the SIRS phenomenon from an infectious process. This study was performed to investigate the SIRS phenomenon after ECMO decannulation.

METHODS: An IRB approved review of 62 patients who survived ECMO between 2010-2014 was done to identify patients who exhibited the post-ECMO SIRS phenomenon. The SIRS phenomenon was defined as having 2 out of the 3 following criteria after ECMO decannulation: fever, leukocytosis, and/or escalation of vasopressors. Patients with the SIRS phenomenon were divided into 2 groups: those with true SIRS (Group TS) vs. infection (Group I). Infection was defined as any positive culture after decannulation. Pre-, intra-, and post-ECMO variables were compared between the two groups to identify risk factors.

RESULTS: 37 (60%) patients fit the criteria for the SIRS phenomenon (29 male, mean age of 48.5 ± 13.4 years, 24 venoarterial (VA) ECMO, 13 venovenous (VV) ECMO, mean ECMO length 10.1 ± 5.1 days). Group TS consisted of 15 patients without any identified source of infection (11 male, mean age of 45.2 ± 13.0 years, 9 VA ECMO, 6 VV ECMO, mean ECMO length 10.7 ± 5.8 days). Group I consisted of 22 patients with various infections, including bacteremia in 7 (32%), pneumonia in 12 (56%), surgical site infection in 3 (14%), and Clostridium difficile infection in 1 (4.5%); infection sites may be overlapped among the patients. Risk factor analysis did not identify pre- or intra-ECMO variables related to the development of true SIRS vs. infection. The post-decannulation duration of vasopressor use was shorter in Group TS (3.7 ± 2.5 days) vs. Group I (6.1 ± 2.9 days), p=0.015. Post-decannulation 30-day survival rate was greater in Group TS (100%) vs. Group I (77%), p=0.047. Post-decannulation leukocytosis, fever, and days on antibiotics were similar between Group TS and Group I.

CONCLUSIONS: True SIRS and infection are common after ECMO decannulation. Compared to those who developed true SIRS, patients who developed infection post-decannulation were found to require a longer course of vasopressors and their post-decannulation 30-day survival rate was found to be decreased. Risk factor analysis did not demonstrate variables to distinguish between post-ECMO true SIRS vs. infection.

Chest. 2015;148(4_MeetingAbstracts):32A. doi:10.1378/chest.2250571