Vital sign metrics of VLBW infants in three NICUs: implications for predictive algorithms

BACKGROUND: Continuous heart rate (HR) and oxygenation (SpO(2)) metrics can be useful for predicting adverse events in very low birth weight (VLBW) infants. To optimize the utility of these tools, inter-site variability must be taken into account. METHODS: For VLBW infants at three neonatal intensive care units (NICUs), we analyzed the mean, standard deviation, skewness, kurtosis, and cross-correlation of electrocardiogram HR, pulse oximeter pulse rate, and SpO(2). The number and durations of bradycardia and desaturation events were also measured. Twenty-two metrics were calculated hourly, and mean daily values were compared between sites. RESULTS: We analyzed data from 1168 VLBW infants from birth through day 42 (35,238 infant-days). HR and SpO(2) metrics were similar at the three NICUs, with mean HR rising by similar to 10 beats/min over the first 2 weeks and mean SpO(2) remaining stable similar to 94% over time. The number of bradycardia events was higher at one site, and the duration of desaturations was longer at another site. CONCLUSIONS: Mean HR and SpO(2) were generally similar among VLBW infants at three NICUs from birth through 6 weeks of age, but bradycardia and desaturation events differed in the first 2 weeks after birth. This highlights the importance of developing predictive analytics tools at multiple sites.

Automated summary

The study analyzed heart rate and oxygenation metrics of VLBW infants at three NICUs, finding similar trends across the sites for these metrics, but differences in bradycardia and desaturation events in the first two weeks after birth.