Near infrared spectroscopy tissue oxygenation in infants with bronchiolitis during mechanical ventilation and spontaneous breathing

Abstract

Introduction. Near-infrared spectroscopy (NIRS) was used in infants with acute bronchiolitis as a noninvasive indicator of tissue oxygenation to determine regional tissue oxygen saturation (rStO2) and fractional tissue oxygen extraction (FTOE) during mechanical ventilation and spontaneous breathing. Methods. Twenty-seven infants with bronchiolitis that needed mechanical ventilation were included in a prospective study. Regional StO2 in brain, liver, kidney and skeletal muscle tissue was measured on admission to the Intensive Care Unit (ICU), on day 1 (D1); after two to three days of mechanical ventilation (D2); on the last day of mechanical ventilation (D3) and during spontaneous breathing (D4). Measurements were conducted by in-vivo optical spectroscopy. For research purposes we divided the infants according to C-reactive protein (CRP) levels, with a cut-off value of 10 mg/ml on admission, into low (l-CRP) and high (h-CRP) groups.Results. During mechanical and spontaneous breathing we found lower StO2 and higher FTOE for skeletal muscle at D4 compared to D1-D2 in the h-CRP group of patients. Differences between l- and h-CRP groups in rStO2 were found for brain tissue on D3, D4, and in rStO2 and FTOE for liver tissue on D3. A strong negative correlation was found between rStO2 and FTOE in all tissues. A positive correlation was found between CRP and rStO2 and negative between CRP and FTOE in skeletal muscle among all patients combined. Conclusion. Only Infants with acute bronchiolitis in the h-CRP group have significant changes in rStO2 and FTOE in skele-tal muscles during mechanical ventilation and spontaneous breathing. Regional StO2 and FTOE in all the other measured tissues never decreased below normal values.