Hypothermia is often used to treat Out of Hospital Cardiac Arrest (OHCA) patients, who often simultaneously receive insulin for stress induced hyperglycemia. This study analyzes insulin sensitivity (SI) variability profiles of OHCA patients undergoing hypothermic treatment to assess its impact on metabolism particularly during cool period. A retrospective analysis of clinically validated model-based insulin sensitivity is identified using data from 240 patients (9988 hours) treated with hypothermia, shortly after admission at the Intensive Care Unit (ICU). The impact on SI is analyzed per-cohort and per-patient for each period of cool and warm by: 1) median SI [IQR], and 2) Hour-to-hour percentage change in SI, (%Δ SI) median [IQR]. These non-parametric metrics assess level and hour-to-hour variability of SI, which will be compared over time on 6-hour timescales.

Overall results show cohort and per-patient median SI levels increased by 35.1% and 26.4% (p < 0.001) between the 0-6 hour block and 6-12 hour block during cool period, and consistent increments are recorded for the consequent blocks. Conversely, cohort and per-patient SI variability decreased by 11.1% and 33.6% (p < 0.001) between the 0-6 hour block and 6-12 hour block. Lower variability decreases are recorded between the 6-12 hour, 12-18 hour and 18-24 hour blocks. However, SI variability rise is recorded between the 18-24 hour and 24-30 hour blocks over the cool to warm transition. It is followed by a significant decreases between the remaining 6-hour blocks. These results represent overall statistically significant trends for this patient cohorts. In summary, OHCA patients treated with hypothermia have significantly lower and more variable insulin sensitivity during the cool period, particularly during the first 12 hours of ICU stay, and improve over time. As the treatment continues, insulin sensitivity variability decreases consistently while rising SI except for a large, significant increase during the cool-warm transition. These results demonstrates a unique evolution for insulin resistance and metabolic variability in this cohort that could be exploited to improve control.