Experimental Human Exposure to High Concentrations of Carbon Monoxide

Abstract

Six healthy male human volunteers were exposed to seven high carbon monoxide (CO) concentrations ranging from 1,000 ppm for ten minutes to 35,600 ppm for 45 seconds. Carbon monoxide was rapidly absorbed and the increase in percent carboxyhemoglobin (COHb) saturation in venous blood per liter of CO mixture inhaled could be accurately predicted by the equation, log (Δ% carboxyhemoglobsn/liter) = 1.036 log (ppm CO inhaled) -4.4793. The abrupt increase in carboxyhemoglobin concentration of 11.6% and 9.1% saturation in two subjects produced the immediate onset of mild frontal headache. The subject exposed to 35,600 ppm demonstrated slight sagging of the ST-segsnent of lead II. This occurred 20 seconds after the exposure had started and persisted for ten minutes after exposure. Neither the spontaneous nor the evoked electrical activity of the brain exhibited significant changes which could be attributed to CO exposure over the range studied.