SEMIPORTABLE ELECTROCHEMICAL INSTRUMENT FOR DETERMINING CARBON-MONOXIDE IN BREATH

Measurements of carbon monoxide (CO) in breath can be used for the dia gnosis of hemolytic disease. A small, semiportable, easy-to-operate CO instrument was developed at Stanford University and tested at 12 Neon atal Research Network Centers of the National Institute of Child Healt h and Human Development. A syringe pump delivers 7.7 mL of sample per minute through an activated carbon filter to an electrochemical (EC) s ensor having a sensitivity of 0.10 +/- 0.01 V per 1 mu L/L CO in air. The electronically processed sensor signal is displayed on a digital m ultimeter. For a typical end-tidal CO measurement, corrected for inhal ed CO, three 10- to 12-mL breath and room air samples are manually or mechanically collected and analyzed. CO determination in breath sample s from 108 healthy, 1-day-old infants of nonsmoking mothers compared f avorably with determinations by gas chromatography (GC), 1.3 +/- 0.8 v s 1.2 +/- 0.8 (mean +/- SD), respectively, with a regression equation of EC = 0.95 GC + 0.13 (r(2) = 0.98). The results demonstrate that the EC-CO instrument yields results that are comparable with those obtain ed by the more difficult to perform GC assay.