Catheters, Nasogastric, Tonometry
Definition : Nasogastric catheters designed for indirect measurement (i.e., tonometry) of the partial pressure of carbon dioxide (PCO2) in the internal gastric mucosa. These catheters consist of a gas-impermeable sampling tube (usually with length markers) with a gas-permeable balloon attached at its distal end. The gas-permeable balloon is withdrawn after pressure equilibrium is reached, then its content is externally measured with a blood-gas analyzer. Some catheters designed for continuous PCO2 monitoring allow for periodic extraction of gas samples. The intramucosal pH may be also calculated by using the measured PCO2 value and the bicarbonate concentration in a contemporary sample of arterial blood. Tonometry nasogastric catheters are used to facilitate assessment of gastrointestinal perfusion during some surgical procedures and in hemodynamically unstable, critically ill patients.
Entry Terms : "Tonometers" , "Gastric Tonometers" , "Tonometry Catheters" , "Tonometers, Gastric" , "Manometric Catheters" , "Catheters, Manometric"
UMDC code : 18724