Peripheral Perfusion Index: Normative Values from Electronically Reported CCHD Screening

Peripheral perfusion index (PPI) represents the ratio of pulsatile to non-pulsatile blood flow in an extremity and may be a valuable supplement to pulse oximetry in identification of critical congenital heart disease (CCHD). To date, reference ranges of PPI of healthy neonates have not been published in the United States. We performed an observational retrospective study evaluating the PPI of healthy neonates between 24 and 48 h of life born in Minnesota, United States based on electronic reporting of CCHD screening to the Minnesota Department of Health. We evaluated preductal and postductal PPI measured at 24-48 h of age in 11,179 healthy infants born between 35- and 41-weeks gestation. We found that preductal PPI is significantly greater than postductal PPI and that PPI increases with gestational age and with birth weight. There was no difference in PPI by sex when adjusting for birth weight. Smoothed percentile curves of preductal and postductal PPI by gestational age were derived using the GAMLSS R Package with a Sinh-Arcsinh distribution. Our study is the first large, population-based study to establish normative data for PPI in healthy neonates in the United States. Our data overall replicate trends observed in large studies from India and China. Further research is needed to determine feasibility and utility of incorporation of PPI into CCHD screening.