Perfusion index as adjunct to SNAPPE-II for early risk stratification of sepsis-dominated adverse outcomes in neonates: Exploratory prospective cohort study
Hanshmani P. Chaudhary, Syed Moiz Ahmed, Richa Joshi, Shantanu Shubham, Naini PuriBackground
Illness-severity scores such as the Score for Neonatal Acute Physiology with Perinatal Extension-II (SNAPPE-II) discriminate mortality well but morbidity less well. Whether serial perfusion index (PI), a continuous bedside perfusion measure, adds prognostic information beyond SNAPPE-II is unknown, particularly in late-preterm and term populations in low- and middle-income countries.
Methods
In this exploratory prospective cohort, 50 neonates admitted within 12 hours of birth to a level-3 neonatal intensive care unit and requiring arterial blood-gas analysis were enrolled consecutively. SNAPPE-II used worst first-12-h values; PI was measured at 6, 12 and 24 hours. Outcomes were death, major morbidity (sepsis, necrotising enterocolitis, bronchopulmonary dysplasia) and their composite. Given eight deaths, multivariable models were exploratory, using Firth-penalised regression. Discrimination was compared by change in area under the curve (ΔAUC; DeLong and bootstrap confidence intervals) with optimism correction. Serial PI was analysed using a random-intercept linear mixed model with time × outcome interaction.
Results
Mortality was 16.0% (8/50); major morbidity, exclusively sepsis, was 44.0% (22/50). Non-survivors had higher SNAPPE-II scores (median 50.5 vs 5.0) and lower PI at all time points (
Conclusions
In this selected cohort, low PI was associated with illness severity and sepsis-dominated adverse outcomes but did not demonstrably improve discrimination beyond SNAPPE-II. Unblinded ascertainment precludes excluding incorporation bias. These hypothesis-generating findings warrant testing, with prespecified thresholds, blinded ascertainment and internal validation, in adequately powered multicentre studies of culture-proven sepsis.