Multisite measurement of regional oxygen saturation in Fontan patients with and without protein-losing enteropathy at rest and during exercise

Abstract

BACKGROUND: Protein-losing enteropathy (PLE) is a severe complication of Fontan circulation with increased risk of end-organ dysfunction. We evaluated tissue oxygenation via near-infrared spectroscopy (NIRS) at different exercise levels in Fontan patients. METHODS: Assessment of multisite NIRS during cycle ergometer exercise and daily activities in three groups: Fontan patients with PLE; without PLE; patients with dextro-transposition of the great arteries (d-TGA); comparing univentricular with biventricular circulation and Fontan with/without PLE. Renal threshold analysis (<65%;<55%;<45%) of regional oxygen saturation (rSO2) was performed. RESULTS: Fontan patients showed reduced rSO2 (p < 0.05) in their quadriceps femoris muscle compared with biventricular d-TGA patients at all time points. rSO2 in renal tissue was reduced at baseline (p = 0.002), exercise (p = 0.0062), and daily activities (p = 0.03) in Fontan patients with PLE. Renal threshold analysis identified critically low renal rSO2 (rSO2 < 65%) in Fontan patients with PLE during exercise (95% of monitoring time below threshold) and daily activities (83.7% time below threshold). CONCLUSION: Fontan circulation is associated with decreased rSO2 values in skeletal muscle and hypoxemia of renal tissue solely in patients with PLE. Reduced rSO2 already during activities of daily life, might contribute to comorbidities in patients with Fontan circulation, including PLE and renal failure.

How to Administer Near-Infrared Spectroscopy in Critically ill Neonates, Infants, and Children

“…Deriving values simultaneously from several sites enables a great variety of setups according to each specific clinical or scientific question. For example, NIRS and multisite NIRS can be used outside of critical care and even during exercise 12 .…”

“…A probe on the skin emits near-infrared light (700 -1000 nm) 11 that penetrates tissue and bone up to a depth of approximately 1-3 cm, thereby being scattered, absorbed and reflected 12 . Detectors in the probe sense the amount of reflected light -representing the relative amount of deoxygenated haemoglobin -and calculate a numerical value that indicates the regional oxygenation saturation in percent (%) 2 .…”