Near-infrared spectroscopy measurement of abdominal tissue oxygenation is a useful indicator of intestinal blood flow and necrotizing enterocolitis in premature piglets

Abstract

Purpose: A major objective of necrotizing enterocolitis (NEC) research is to devise a noninvasive method of early detection. We hypothesized that abdominal near-infrared spectroscopy (A-NIRS) readings will identify impending NEC in a large animal model.

Methods: Piglets were prematurely delivered and received parenteral nutrition followed by enteral feedings. Serial A-NIRS readings were obtained for 5 days, and animals were monitored for NEC. Separately, A-NIRS readings were obtained in healthy piglets to validate the correlation of A-NIRS with splanchnic oxygen delivery.

Results: Of 29 piglets, 3 developed NEC. Eleven piglets without NEC died prematurely. Fifteen piglets remained healthy, had normal histologic assessment of their intestines, and served as controls. Abdominal near-infrared spectroscopy readings within 12 hours of birth were significantly lower in animals that developed NEC compared with healthy littermates (4% vs 33%, P = .02). For all time-points measured, A-NIRS readings were significantly lower in the NEC group compared with controls (21% vs 55%, P < .001). Abdominal near-infrared spectroscopy readings correlated with both decreased pulse oximetry readings during apneic episodes (r = 0.96) and increased superior mesenteric artery flow in response to glucagon-like peptide 2 (r = 0.67).

Conclusion: Abdominal near-infrared spectroscopy is capable of detecting alterations in intestinal oxygenation and perfusion in neonatal piglets and may allow early detection of neonates at risk for NEC.

Copyright © 2011 Elsevier Inc. All rights reserved.

Figures

Figure 1

Timeline of parenteral and enteral nutrition for necrotizing enterocolitis study

Figure 2

a. Gross examination of the abdominal viscera of a healthy control piglet. b. Gross examination of NEC piglet organs shows hyperemic, congested bowel with areas of necrosis in the distal small intestine. c. Histologic examination of normal small intestine of control piglet. d. Histologic examination of small intestine of NEC piglet shows inflammatory infiltrate, engorged vasculature, and the absence of intact microvilli.

Figure 3

Abdominal StO2 measurements show significantly lower A-NIRS values for NEC vs. control piglets at multiple time points (* indicates p<0.05).

Figure 4

Response of superior mesenteric artery (SMA) blood flow, abdominal StO2, and peripheral SaO2 to GLP-2 analog infusion in healthy piglets (n=10). SMA flow increases by 140% ± 7% upon GLP-2 analog infusion. Abdominal StO2 mirrors this change in SMA flow with an increase of 13% ± 1% while peripheral SaO2 remains unchanged.

Figure 5

Apnea-induced changes in StO2, SaO2, and heart rate of healthy piglets (n=3). Abdominal StO2 and peripheral SaO2 exhibit a similar proportional decline during apneic episodes with a compensatory increase in heart rate. Both StO2 and SaO2 rebound with similar slopes.