Pulse Rate Variability as a Predictor for Length of Stay for Patients with Bronchiolitis in the Pediatric Intensive Care Unit

Patients admitted to pediatric Intensive Care Unit (PICU) due to bronchiolitis have unpredictable length of stay (LOS). The aim of this study is to observe the difference in the relationship between pulse rate variability (PRV) and heart rate variability (HRV) for patients with bronchiolitis admitted to the PICU and its association with LOS. The first 12 hours of physiologic data after PICU admission were used for analysis. Electrocardiogram (ECG) and photoplethysmography (PPG) were divided into non-overlapping 5-minute segments, and R-peak and PPG-peak were obtained to calculate PRV and HRV. Correlation was calculated between HRV and PRV for each PICU LOS group and was tested with Fisher Z-transformation. The student’s t-test, chi-square test was performed on other independent variables, including age, gender, prematurity and ventilation type. A total of 119 patients were included in this study. For both LOS groups, PRV and HRV parameters were significantly different. However, the correlations between PRV and HRV parameters were significantly higher in the short-stay group compared to the long-stay group. This study demonstrates that the correlation between the PRV and HRV is lower in patients with longer length of stay, suggesting this can be a potential metric for LOS in PICU.