258 - Heart Rate Variability Analysis Detects Dynamic Physiologic Changes in Neonates on ECMO

Publication Number: 4254.258

Sara Manetta, University of Virginia School of Medicine, Charlottesville, VA, United States; Alexander E. Paget-Brown, University of Virginia School of Medicine, Keswick, VA, United States; Leigh M.. Finnegan, Children's National Health System, Washington, DC, United States; Rathinaswamy Govindan, Children's National Hospital, Washington, DC, United States; Douglas Lake, University of Virginia, Charlottesville, VA, United States; Brynne Sullivan, University of Virginia School of Medicine, Charlottesville, VA, United States; Suma B. Hoffman, Children’s National, Bethesda, MD, United States; Venkata Chaitanya Chirumamilla, Childrens National Hospital, Washingotn DC, DC, United States

Background: Neonates supported with extracorporeal membrane oxygenation (ECMO) experience substantial physiologic stress and autonomic instability. Continuous heart rate (HR) data may capture early physiologic changes not clinically evident. Quantitative analysis of HR variability may provide insights into autonomic regulation and outcomes during ECMO.

Objective: To characterize temporal changes in heart rate variability (HRV) in neonates during ECMO and evaluate associations between HRV and ECMO duration.

Design/Methods: We retrospectively studied infants with continuous HR data (sampled at 0.5 Hz) available who received ECMO at two Level IV NICUs. HRV was quantified using the standard deviation of HR, and averaged in 24-hour epochs. The peri-cannulation hour was excluded. Mixed-effects models with random intercepts estimated changes in HRV across time points: 24 hours before ECMO, and 0-24, 24-48, 48-72, and 72-96 hours during ECMO. We evaluated the associations between HRV and ECMO duration using linear regression analysis in survivors.

Results: We included 71 infants with mean gestational age of 38.7 weeks and mean birthweight of 3305g. Patients were 56% male. Median ECMO duration was 5 days (IQR 1.4-7.5) and median hospital stay was 24 days (IQR 10-36). Of 71 infants, 49 survived and 22 died with a 31% mortality rate.. Mean HRV was lowest in the 24 hours after ECMO start (Figure 1). We found significant increases in HRV occurred between early and later ECMO periods: before ECMO HRV and 0-24 hour period (p=0.012), 0-24 and 24-48 hour periods (p=0.008), 0-24 and 48-72 hour periods (p < 0.0001), and 0-24 and 72-96 hour periods (p < 0.0001, Figure 1). Increases in HRV between 0-24 and 72-96 hours were inversely correlated with ECMO duration (r=-0.91, p=0.039, R²=0.10, Figure 2).

Conclusion(s): Continuous HR monitoring revealed dynamic changes in HRV during ECMO, indicating early autonomic suppression followed by a gradual recovery. Greater HRV recovery was associated with shorter ECMO duration, indicating potential prognostic value. Continuous HR analytics may serve as a physiologic biomarker for monitoring autonomic recovery and clinical trajectory in neonates undergoing ECMO.

Figure 1. HRV Average During ECMO
Average HRV over 24-hour periods before ECMO and 0-24, 24-48, 48-72, and 72-96 hours during ECMO. Dots represent a 24-hour average of HR standard deviation. Bracketed lines show the standard deviation of the average value. Mixed effect modeling random intercept model, to estimate the significance of changes over time. * p-value <0.05, ** p-value <0.01, and **** p-value <0.0001.

Figure 2. HRV Correlation to ECMO duration.
Correlation between average HRV difference from 0-24 hour period to 72-96 hour period and ECMO duration. HRV was measured by HR standard deviation. Dark blue line indicates the fit line, light blue shadow shows the 95% confidence limits, and light blue dotted line indicates 95% prediction limits.