Measuring tissue oxygen saturation via spectrometer in children.

BACKGROUND: : Near-infrared spectroscopy is a new noninvasive method of monitoring oxygen saturation at a tissue level. The purpose of this study was to evaluate new near-infrared tissue spectrometer InSpectra (Hutchinson Technology Inc.) in children and to determine preferable areas of the body to measure tissue oxygen saturation (StO2).

METHODS: : Prospective study at a pediatric emergency department. Children aged 0 years to 17 years with no respiratory distress participated in this study. StO2 on deltoid muscle, thenar eminence, forearm, calf, bicep, and tricep was measured at triage with a 25-mm probe.

RESULTS: : A total of 310 patients were recruited. The mean age of participants was 6.8 years +/- 4.4 years and 53% were males. Average StO2 was 84% (95% confidence interval, 81-87%) on the bicep muscle, 83.5% (95% confidence interval, 82-85%) on the deltoid muscle and significantly (p < 0.05) lower on other areas. Variation of StO2 was lower on the bicep, deltoid, and thenar muscles. Regression analysis showed significant linear relationship between patients' age and StO2 measured on the thenar eminence (beta = 0.3, R = 0.08, p < 0.001) and between patients' weight and StO2 on the thenar eminence (beta = 0.3, R = 0.07, p < 0.001). StO2 in febrile patients was similar to afebrile children, except thenar eminence where StO2 was significantly lower (p = 0.002). Less than 5% reported any type of pain or cried during StO2 measurement, which did not differ from pulse oximetry.

CONCLUSION: : Bicep and deltoid muscles are the most appropriate areas to measure StO2 using the 25-mm transducer in children of different ages. The use of near-infrared spectroscopy on the thenar eminence, which is usually used for measurement in adults, has varied results in children depending on the age, weight, and presence of fever.