Peripheral perfusion index percentiles for healthy newborns by gestational age and sex in China

Peripheral perfusion index (PPI) percentiles for newborns serve as an important observation tool in clinical practice, but research pertaining to reference ranges are lacking. The aim of this study was to establish PPI percentiles for healthy newborns by gestational age and sex at 24-48hours of life. We conducted an observational study and examined PPI values at 24-48hours of life in 3814 asymptomatic newborns born between 35 and 41 weeks gestation who did not need medical treatment from June 1, 2016 to May 31, 2017 at two maternity hospitals in Shanghai. Linear regression analysis was carried out on the associations between PPI values and variables such as gestational age, sex, and birthweight. Pre-ductal PPI values linearly increased with gestational age (beta: 0.072; 95% CI: 0.037, 0.107; P=0.000). Post-ductal PPI values were also mainly related to gestational age (beta: 0.051; 95% CI: 0.018, 0.085; P=0.003). Smoothed reference curves for pre- and post-ductal PPI values by gestational age and sex were derived from LMS Chart Maker. Our study is the first study to establish PPI percentiles curves for healthy newborns by gestational age and sex at 24-48hours of life. Further research is required for the implementation of PPI curves into clinical practice.