**4. Splanchnic (gut) NIRS**

Monitoring the GI tract as opposed to monitoring the brain or kidneys is more complex since the gut is a hollow or gas and stool filled, moving structure, in close proximity of stomach and bladder, which could affect its position and functioning. Proper probe placement may therefore be a challenge. In addition movements of the baby and pull on electrodes are more likely. A recent small study by Gillam-Krakauer et al. using Doppler confirmed that splanchnic NIRS reflects bloodflow to the small intestine. (Gillam-Krakauer et al., 2011)

McNeill's study of splanchnic/abdominal rSO2 in healthy preterm infants between day 0 and day 21 found that baseline changed over time. Overall abdominal rSO2 values were significantly lower than cerebral and renal values. The baseline increased over time. When comparing patients born at 32 and 33 weeks to those born at 29 and 30 weeks gestation, higher weekly means were observed in the 2nd week of life in the older group. (McNeill et al., 2010, 2011)

These changes too may indicate regional developmental maturation. For abdominal rSO2 long- and short-term variability is much higher and exceeds 20%. It may be associated with clinical and caregiving events and warrants further investigation/characterization. (McNeill et al., 2010, 2011)

Cortez found higher splanchnic rSO2-s and variability to be associated with a healthy gut, whereas infants with necrotizing enterocolitis, a condition of devastating bowel inflammation, had low splanchnic rSO2s and decreased variability. (Cortez et al., 2010, 2011)
