Methods
Population: We performed a retrospective analysis of ECMO
patients admitted to the Johns Hopkins Hospital between 2016 and 2019.
We included all adult patients (age >18 years), excluding
patients who underwent multiple runs to minimize the potential bias
resulting from severe illness. This study was carried out with the
approval of the Johns Hopkins institutional review board (IRB00216321).
Informed consent and clinical trial registration are not applicable for
this study. Demographics, past medical history, laboratory
values, ECMO indication, hemodynamic data, and Sequential Organ Failure
Assessment (SOFA) score (day 1) were collected.11 ABI
included ischemic stroke, intracranial hemorrhage (ICH), cerebral edema,
hypoxic ischemic brain injury, seizures, and coma (Glasgow Coma
Scale<8) despite being off sedation for >24
hours.12 Systemic hemorrhage included surgical site
bleeding, gastrointestinal bleeding, disseminated intravascular
coagulation, pulmonary hemorrhage, and genitourinary bleeding.
Exposure: Temperature measurements were collected during the
first 24 hours after ECMO cannulation. Bladder temperatures were
collected hourly, while additional recordings were obtained when
clinically indicated. Metrics for hypothermia included: mean temperature
and time (hours) spent between 32-36°C.5
Outcomes: The primary outcome was neurological function at
discharge defined by modified Rankin Scale (mRS), with a score of 0-3
defined as good neurological outcome (4-6: poor).13Secondary outcomes included in-hospital mortality and systemic
hemorrhage.
Statistical analysis: Demographic and clinical variables for
hypothermia vs. no hypothermia were compared by unpaired t-test,
chi-squared test, or Mann-Whitney U test as appropriate. Results were
expressed as the mean with standard deviation if normally distributed or
as the median with quartiles if non-normally distributed for
quantitative variables and as proportions for categorical variables.
Carefully selected pre-specified variables a priori that showed
significant association with primary outcome in univariate analyses were
used in the multivariable models reported. A p value <0.05 was
considered statistically significant. Odds ratios (ORs) with 95%
confidence intervals (CIs) were reported. All analyses were carried out
in STATA 15 (College Station, TX, USA).