Objectives: To test the hypothesis that forced-air warming of critically ill afebrile sepsis patients improves immune function compared to standard temperature management.
Design: Single-center, prospective, open-label, randomized controlled trial.
Setting: One thousand two hundred-bed academic medical center.
Patients: Eligible patients were mechanically ventilated septic adults with: 1) a diagnosis of sepsis within 48 hours of enrollment; 2) anticipated need for mechanical ventilation of greater than 48 hours; and 3) a maximum temperature less than 38.3°C within the 24 hours prior to enrollment. Primary exclusion criteria included: immunologic diseases, immune-suppressing medications, and any existing condition sensitive to therapeutic hyperthermia (e.g., brain injury). The primary outcome was monocyte human leukocyte antigen (HLA)-DR expression, with secondary outcomes of CD3/CD28-induced interferon gamma (IFN-γ) production, mortality, and 28-day hospital-free days.
Interventions: External warming using a forced-air warming blanket for 48 hours, with a goal temperature 1.5°C above the lowest temperature documented in the previous 24 hours.
Measurements and main results: We enrolled 56 participants in the study. No differences were observed between the groups in HLA-DR expression (692 vs 2,002; p = 0.396) or IFN-γ production (31 vs 69; p = 0.678). Participants allocated to external warming had lower 28-day mortality (18% vs 43%; absolute risk reduction, 25%; 95% CI, 2-48%) and more 28-day hospital-free days (difference, 2.6 d; 95% CI, 0-11.6).
Conclusions: Participants randomized to external forced-air warming did not have a difference in HLA-DR expression or IFN-γ production. In this pilot study, however, 28-day mortality was lower in the intervention group. Future research should seek to better elucidate the impact of temperature modulation on immune and nonimmune organ failure pathways in sepsis.
Trial registration: ClinicalTrials.gov NCT02706275.
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