Rats were drowned in fresh water collected from a river, and kept immersed in the water for four weeks in separate bottles. When five rats were placed outside in the shade, where the temperature varied from 1 to 9°C, carboxyhemoglobin (HbCO) saturations in the blood and thoracic cavity fluid were not more than 1% and 10% respectively. When fifteen rats were immersed at 8-9°C, HbCO saturations in the body cavity fluids were more than 20 % in six. HbCO saturations in the blood, however, were not more than 10 % in all cases.
The results indicate that low carbon monoxide (CO) levels are produced in the blood and high CO levels are formed in the body cavity fluid, and that body cavity fluid should not be used for CO determination.