0633. Time-resolved spectroscopy using non-invasive monitoring may detect hapatic ischemia

Introduction

The aim of the present study was to investigate whether the changes in hepatic oxygenation can be detected by time-resolved spectroscopy (TRS) placed on the skin surface above the liver.

Methods

With approval of the local Hospital Ethics Committee and informed consent, 6 healthy volunteers aged 28.8 years (25-36 years), and 5 patients with chronic renal failure aged 70.6 years (58-81 years) were studied. In 6 healthy volunteers, following the echography, TRS (TRS-10, Hamamatsu Photonics K.K., Hamamatsu, Japan) probe consisting of a near-infrared light (at 760 nm, 800 nm, 835 nm) emitter and a receiver optode, was placed 4 cm apart on the abdominal skin surface above the liver or apart from the liver at least 10 cm. In 5 patients with chronic renal failure, following the echography, TRS probes were placed 4 cm apart on the skin surface above the liver during hemodialysis (HD).

Results

In 6 healthy volunteers, the values of abdominal total hemoglobin concentration (tHb) was significantly higher in the liver area than in the other area (80.6±26.81mM vs 44.6±23.1mM, P=0.0017), while the value of abdominal SO₂ in the liver area was nearly the same as that in the other area (71.5±3.6% vs 73.6±4.6%, P=0.19). The values of mean optical path length and scattering coefficient (µ´s) at 800 nm in the liver area were significantly different from those in the other area (21.3±4.9 cm vs 29.2±5 cm, p=0.0004, and 7.97±1.14cm-1vs 9.02±0.51cm-1, P=0.015). One of 5 patients with chronic renal failure complained of the severe abdominal pain during HD, and the abdominal SO₂ was decreasing from 53% to 22%, but the pain relief occurred following cessation of HD, and SO₂ recovered to the baseline.

Conclusions

Our data suggest that the optical properties of the liver may be measured by the TRS placed on the skin surface, and the hepatic oxygenation may act as a non-invasive monitoring for early detection of intestinal ischemia.