Absorption spectra of early stool from preterm infants need to be considered in abdominal NIRS oximetry

Helene Isler; Daniel Schenk; Jérôme Bernhard; Stefan Kleiser; Felix Scholkmann; Daniel Ostojic; Alexander Kalyanov; Linda Ahnen; Martin Wolf; Tanja Karen

doi:10.1364/BOE.10.002784

Absorption spectra of early stool from preterm infants need to be considered in abdominal NIRS oximetry

Biomed Opt Express. 2019 May 15;10(6):2784-2794. doi: 10.1364/BOE.10.002784. eCollection 2019 Jun 1.

Authors

Affiliations

¹ Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zürich, 8091 Zürich, Switzerland.
² CARAG AG, 6340 Baar, Switzerland.

Abstract

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of the preterm infant. Low abdominal tissue oxygen saturation (StO₂) measured by near-infrared spectroscopy (NIRS) oximetry may be an early sign of NEC relevant for treating or even preventing NEC. However, current commercial NIRS oximeters provide inaccurate StO₂ readings because they neglect stool as an abdominal absorber. To tackle this problem, we determined the optical properties of faeces of preterm infants to enable a correct abdominal StO₂ measurement. In 25 preterm born infants (median age 31 0/7 ± 2 1/7 weeks, weight 1478 ± 511 g), we measured their first five stool probes with a VIS/NIR spectrometer and calculated the optical properties using the Inverse Adding Doubling (IAD) method. We obtained two absorption spectra representing meconium and transitional stool. Probabilistic cluster analysis correctly classified 96 out of 107 stool probes. The faeces spectra need to be considered to enable correct abdominal StO₂ measurements with NIRS oximetry.