Double-contrast examination of the colon with carbon dioxide: the use of effervescent powder

CO2 has distinct advantages over room air for doublecontrast examination of the colon [1 -4J. Not only has CO2 been proved safe, but also it has been shown to be absorbed much more rapidly from the gastrointestinal tract than is the nitrogen in room air (absorption occurs 30 to 100 times faster) El , 2J. Thus, with CO2, there is a marked decrease in bowel distension over a much shorter period of time, with resultant increased comfort after the barium enema examination [2]. This paper describes a simplified method of using CO2 for double-contrast examination of the colon that eliminates the need to employ or store a CO2 tank.