45
Introduction – English - USA
The MicroCO meter is based on an electrochemical fuel cell sensor,
which works through the reaction of carbon monoxide (CO) with an
electrolyte at one electrode, and oxygen (from ambient air) at the
other. This reaction generates an electrical current proportional to CO
concentration. Output from the sensor is monitored by a micro-
processor, which detects peak expired concentrations of alveolar gas.
This is then converted to % carboxyhemoglobin (%COHb) using the
mathematical relationships described by Jarvis et al
1
, for
concentrations below 90 ppm, and by Stewart et al
2
for higher levels.
Raised levels of carboxyhemoglobin are most commonly caused by
accidental smoke inhalation/CO poisoning or cigarette smoking. The
MicroCO includes a countdown timer as an aid to timing the breath
holding period prior to exhalation.
The results are displayed on a clear LCD display. Warning lights are
provided to give an instant indication of the smoking level.
The countdown timer, warning light levels, and the alarm level are
user adjustable when the unit is connected to a PC running COBRA
software.
Note: the countdown timer, warning light levels, and the alarm
level used throughout this manual are the factory settings and
may have been changed.
References
1. Jarvis MJ, Belcher M, Vesey C, Hutchison DCS
Low cost carbon monoxide monitors in smoking
assessment
Thorax 1986; 41: 886-887
2. Stewart RD, Stewart RS, Stamm W, Seleen RP
Rapid estimation of carboxyhemoglobin levels in fire
fighters
JAMA 1976; 235, 390-392
To Next Page
Loading...
