| 摘要 |
<p>A noninvasive device and methods for measuring the end-tidal carbon monoxide concentration in a patient's breath, particularly newborn and premature infants. The patient's breath is monitored. An average carbon monoxide concentration is determined based on an average of discrete samples in a given time period. The ratio of the end-tidal portion of the breath flow sample is separately determined, preferably based on monitoring the level of carbon dioxide in the gas sample and identifying the carbon dioxide concentration levels corresponding to the end-tidal portion of the breath sample. The sensed carbon monoxide level is converted to the end-tidal carbon monoxide level by subtracting the ambient carbon monoxide level and dividing the remainder by the ratio of end-tidal breath to breath in the breath sample. An easy to use microcontroller-based device containing a carbon dioxide detector, a carbon monoxide detector and a pump for use in a hospital, home, physician's office or clinic by persons not requiring high skill and training is described. A replaceable filter unit made of a single tri-lumen PVC extrusion and a tube segment interconnecting two of the lumens used to provide the consumable filtration material. The filtration material is interposed between the carbon dioxide sensor and the carbon monoxide sensor which are mounted inside the monitor housing. The filter unit also interfaces the canula for receiving the patient's breath sample and a hydrophobic filter between the patient and the carbon dioxide monitor. The filter unit is replaceable when the filtration medium is no longer effective or for use with different patients and may be disposable.</p> |
