Title: Statistical methods for characterizing transfusion-related changes in regional oxygenation using Near-infrared spectroscopy (NIRS) in preterm infants,
Abstract: Near infrared spectroscopy (NIRS) is an imaging-based diagnostic tool that
provides non-invasive and continuous evaluation of regional tissue oxygenation
in real-time. In recent years, NIRS has show promise as a useful monitoring
technology to help detect relative tissue ischemia that could lead to
significant morbidity and mortality in preterm infants. However, some issues
inherent in NIRS technology use on neonates, such as wide fluctuation in
signals, signal dropout and low limit of detection of the device, pose
challenges that may obscure reliable interpretation of the NIRS measurements
using current methods of analysis. In this paper, we propose new statistical
methods to analyse mesenteric rSO2 (regional oxygenation) produced by NIRS to
evaluate oxygenation in intestinal tissues and investigate oxygenation response
to red blood cell transfusion (RBC) in preterm infants. We present a mean area
under the curve (MAUC) measure and a slope measure to capture the mean rSO2
level and temporal trajectory of rSO2, respectively. Estimation methods are
developed for these measures and nonparametric testing procedures are proposed
to detect RBC-related changes in mesenteric oxygenation in preterm infants.
Through simulation studies, we show that the proposed methods demonstrate
improved accuracy in characterizing the mean level and changing pattern of
mesenteric rSO2 and also increased statistical power in detecting RBC-related
changes, as compared with standard approaches. We apply our methods to a NIRS
study in preterm infants receiving RBC transfusion from Emory Univerity to
evaluate the pre- and post-transfusion mesenteric oxygenation in preterm
infants.