Delayed Fever and Neurological Outcome after Cardiac Arrest: A Retrospective Clinical Study

Abstract

Background: The aim of this study was to evaluate the association between fever after the first days of ICU stay and neurological outcome after cardiac arrest (CA).

Methods: We retrospectively analyzed CA patients admitted to intensive care unit (ICU).

Inclusion criteria: age ≥18 years, Glasgow Coma Scale score ≤8 at ICU admission and assessment of body core temperature (BCT) using bladder or intravascular probes.

Exclusion criteria: ICU length of stay (LOS) <3 days and pregnancy. The primary endpoint was neurological outcome assessed with Cerebral Performance Category (CPC) scale 6 months after CA.

Results: One hundred thirty-two patients were analyzed. Fever was present in 105 (79.6%) patients. Variables associated with unfavorable outcome were (1) older age (p < 0.0025); (2) non-shockable cardiac rhythms (p < 0.0001); (3) higher Simplified Acute Physiology Score (SAPS) II (p < 0.0001); (4) pupillary abnormalities at ICU admission (p < 0.018); and (5) elevated degree of maximal BCT (Tmax) during ICU stay (p < 0.046). After multivariate analysis, Tmax maintained a significant relationship with neurological outcome. An increase of 1 °C in Tmax during ICU stay decreased the odds ratio for a favorable outcome by a factor of 31% (p < 0.001). Moreover, we discovered a significant interaction between the day of Tmax (t-Tmax) and Tmax (p = 0.004); the later Tmax occurs, the more deleterious effects are observed on outcome.

Conclusions: Fever is frequent after CA, and Tmax in ICU is associated with worsened neurological outcome. This association becomes stronger as the timing of Tmax extends further from the CA.

Keywords: Cardiac arrest; Fever; Intensive care unit; Neurological outcome; Temperature management.