Abstract
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 h of physiologic data after PICU admission were used for analysis. Electrocardiogram (ECG) and photoplethysmogram (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 both PICU short-stay and long-stay groups. A total of 119 patients were included in this study, where 66 are short-stay and 53 are long-stay group. For both LOS groups, PRV and HRV parameters were significantly higher HRV parameters compared to PRV. SDSD, SDNN, RMSSD, pNN50, SD1, and SD2 were 13.72, 10.24, 13.72, 0.77, 9.7, 10.6, and 0.85 for HRV. For PRV it was 5.88, 4.83, 5.88, 0.75, 4.16, 5.28, and 0.85. However, in the comparison of the correlations between PRV and HRV parameters, the short-stay group had significantly higher correlation compared to the long-stay group. The correlations in the short-stay group are above 0.72-0.82, whereas for the long-stay group the correlation ranged from 0.29 to 0.67. 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.