Probability trends in the assessment of cardiovascular autonomic fluctuations during cold pressor tests

Eighteen healthy volunteers between 23 and 53 years of age (mean age 34.9 plusmn 9.8 years) were exposed to CPT while continuous ECG recordings were collected. HRV parameters, including root mean square of successive differences (RMSSD) and low frequency (LF) and high frequency (HF) components, were obtained during baseline and each stage of CPT using an autoregressive (AR) model with Burgpsilas method to evaluate short windows of observation while preserving adequate frequency resolution. HRV parameters obtained during immersion of the hand in cold water, after withdrawal, and every 3 minutes after withdrawal were compared to baseline parameters. A probability trend was updated every 10 seconds for each parameter and p < 0.05 was considered significant. Preliminary results show that probability trends from RMSSD and HF provide consistent and prompt information about the sympathetic activation. These results could be applied in the setting of anesthesia and intraoperative monitoring, where sympathovagal imbalances can provide an early warning of physiological stress and thus facilitate timely interventions.