Firefighting Case Studies

Firefighting is considered as one of the most challenging and dangerous profession due to the exposure of various hazards, chemically or physically, encountered by firefighters worldwide. The products of combustion during a fire consist of organic materials in which the primary chemical element is composed of carbon. The carbon compound evolves to carbon dioxide and water molecules when burned completely during complete combustion. However, combustion is occasionally complete. Incomplete combustion leads to formation of carbon monoxide (CO), thus making exogenous CO ever present at every fire (Stefanidou, Athanaselis, & Spiliopoulou, 2008).

It has been known that CO is responsible for a large percentage of accidental poisonings and deaths
Following absorption, CO is rapidly distributed into the blood: there is no metabolism of absorbed CO (Levine, 2003). It binds reversibly to Hb, however, due to the greater affinity of CO as compared to O2, CO not readily displaced at normal O2 concentrations: it does not spontaneously displaced from Hb but is displaced by mass action of O2. CO level in blood is represented as the percentage of Hb in the form of carboxyhemoglobin (COHb) which is a Hb-CO complex. Human body have 0.1-1.0% (Mercury, 1990), 0.4-0.7% (Widdop, 2002) endogenous COHb saturation produced through the process of natural degradation of Hb. The rate of COHb formation depends on CO concentration in inhaled air and the exertional level when an individual breathing it in. Despite the fact that COHb formation is a reversible process, the half-time of CO elimination from blood is consider long: ranging from 2-6.5 hours (Gardner, Crapo, & McClellan, 1999); 5-6 hours at normal O2 concentration (21%), 30-90 minutes at 100% O2 and 30 minutes under hyperbaric oxygen conditions (Levine, 2003). This is due to the tight binding of CO to Hb.
This study used a simple conventional spectrophotometry for assessment and percentage determination of COHb. Hb molecules are easily measured with response to various Hb derivatives: each derivatives specifically possesses altered molecular structure of heme moiety, thus, give rise to unique absorption spectra, enabling it possible to determine the percentage saturation of COHb present in blood (Haymond, 2006). This report will only cover the toxicological level of CO gas, in which among the most toxic products of