600 - Heart rate variability to assess autonomic stress response during simulated neonatal resuscitation

Poster Number: 600
Publication Number: 600.118

Helen Hu, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, United States; Rakesh Sahni, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, United States; Tina A. Leone, Columbia University, New York, NY, United States; Kathleen G. Brennan, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, United States; Diana Vargas, Columbia University, New York, NY, United States

Background: Neonatal resuscitation is an inherently stressful clinical situation. Improving understanding of individuals’ stress response through quantitative assessments of stress may impact preparation and training for these uniquely challenging clinical situations. Beat-to-beat heart rate variability (HRV) has been used as a physiologic marker of stress in various simulation studies, and may be a useful quantitative tool to assess autonomic stress response during neonatal resuscitation.

Objective: The objective of this study was to evaluate the utility of time and frequency domains of HRV as markers of stress during simulated neonatal resuscitation.

Design/Methods: This is a prospective study of neonatology fellows and neonatal advanced practice practitioners. All participants complete a survey regarding basic demographic information, neonatal training, and experience in the NICU. A 10-minute neonatal resuscitation simulation is performed while wearing the polar H10 chest strap, a biometric device that continuously measures heart rate (HR) data including beat-to-beat (RR) intervals. Required maneuvers during the simulation include positive pressure ventilation, intubation, and chest compressions. HRV analysis is performed to yield standard time- and frequency domain indices. Pearson’s correlation is used to describe the relationship between HR, RR interval, root mean square of successive RR interval differences (RMSSD; reflecting parasympathetic activity), and low to high frequency HRV ratio (LF/HF ratio; reflecting sympathetic activity).

Results: Preliminary analysis of 18 completed simulations showed an averaged mean HR 100.1±14.9 beats per minute (bpm), mean RR interval 613±95 milliseconds (ms), mean RMSSD 20.5±9.4, and average LF/HF ratio of 3.9±1.6. Across various subjects, higher HR was associated with lower RMSSD (r= -0.79, p < 0.001), while increases in RR interval were associated with increasing RMSSD (r= 0.82, p< 0.00005). HR and LF/HF ratio showed positive correlation trends (r= 0.34, p= 0.16) and RR interval and LF/HF ratio showed negative correlation trends (r= -0.35, p=0.15) in this ongoing study.Conclusion(s): Preliminary analysis shows that higher mean HR and lower mean HRV is associated with decreased parasympathetic activity/vagal tone. These data demonstrate reproducibility for HRV as a potential tool for measurement of the autonomic stress response during simulated neonatal resuscitation.
Figure 1. Relationship between (A) mean heart rate and average root mean square of successive RR interval differences (RMSSD) and (B) mean RR interval and average RMSSDA: Increased mean heart rate during simulation was associated with decreased RMSSD (r= -0.79, p < 0.001). RMSSD is a proxy for parasympathetic nervous system activity.
B: Increased heart rate variability was associated with increasing RMSSD (r= 0.82, p < 0.00005).
Figure 2. Relationship between (A) mean heart rate and low to high frequency power HRV (LF/HF) ratio and (B) mean RR interval and LF/HF ratioRelationship between (A) mean heart rate and LF/HF ratio (r= 36, p= 0.16); and (B) mean RR interval and LF/HF ratio (r=0.35, p=0.15). LF/HF ratio is strongly influenced by sympathetic nervous system activity.