Am. J. Respir. Crit. Care Med.,
Volume 160, Number 1, July 1999, 317-323
Novel Assessment of Acute Lung Injury by In Vivo
Near-Infrared Spectroscopy
SATOSHI
SHIBATA,
HIDEKI
OHDAN,
TOSHIO
NORIYUKI,
SHINKICHIRO
YOSHIOKA,
TOSHIMASA
ASAHARA,
and
KIYOHIKO
DOHI
Second Department of Surgery, Hiroshima University School of Medicine, Hiroshima, Japan
We investigated the feasibility and validity of near-infrared (NIR) spectroscopy for evaluation of
acute lung injury (ALI). In an in vitro model simulating the spectrophotometric characteristics of the
lung, NIR spectroscopy could precisely detect changes in water volume, suggesting its ability to assess the extent of pulmonary edema caused by ALI. The different grades of ALI were induced in rats
by administering oleic acid and varying the pulmonary ventilation conditions, and NIR spectroscopy
was employed to determine lung water content and hemoglobin (Hb) oxygenation of the lungs. NIR
spectroscopy detected increased water content even in histologically mild ALI. The changes in lung
water content measured by NIR spectroscopy were significantly correlated with gravimetric lung water content (r = 0.877, p < 0.0001). Deoxy-Hb measured by NIR spectroscopy consistently reflected
the histological changes in the lungs, and the deoxy-Hb levels correlated with changes in SaO2 (r = 
0.798, p < 0.0001). These findings demonstrate that NIR spectroscopy can evaluate lung water content and Hb oxygenation quantitatively, and may be a useful tool for assessing pathological status in ALI.
