title: Airflow-based PCO2 monitoring delivers O2 and removes CO2 from the monitored environment.
abstract: Previous investigation has suggested that the use of airflow-based gastrointestinal intraluminal PCO2 (GI PiCO2) monitoring systems may affect the local tissue microenvironment, making it not representative of the organ system as a whole. Therefore, we investigated the effects of using an airflow-based PCO2 monitoring system in a sealed environment. A 250-mL Erlenmeyer flask was filled with 10% CO2/90% N2 and was sealed with probes in place. Using a fiber-optic (Neotrend, Diametrix Medical, St. Paul, MN) system, the PCO2 and PO2 were continuously monitored with and without the airflow-based (Tonocap, Tonometrics, Datex-Ingstrom, Helsinki, Finland) system operating. PCO2 and PO2 remained constant when the airflow-based system was not in operation. PCO2 decreased 25.3 mmHg and PO2 increased 30 mmHg from a starting value of 0 mmHg when the airflow-based system was in operation for 12 h. The use of airflow-based methods for determining GI PiCO2 may influence the values obtained. Nonsample removing techniques such as fiber-optic methods for monitoring GI PiCO2 are preferable because they neither deliver O2 to nor remove CO2 from the local microenvironment.
authors.affiliation: Drake University, Department of Chemistry, Des Moines, Iowa, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Vincent
authors.forename: Brian
authors.initials: B
authors.lastname: Freeman
authors.forename: Eric
authors.initials: E
authors.lastname: Weatherford
authors.forename: LaRhee
authors.initials: L
authors.lastname: Henderson
authors.forename: Charisse
authors.initials: C
authors.lastname: Buising
authors.forename: Piper
authors.initials: P
authors.lastname: Wall
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism*; D004064:Digestive System / Q000098:blood supply* / Q000378:metabolism*; D006801:Humans; D008365:Manometry / Q000295:instrumentation*; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D009102:Multiple Organ Failure / Q000175:diagnosis* / Q000503:physiopathology; D010101:Oxygen Consumption / Q000502:physiology*; D011237:Predictive Value of Tests; D011312:Pressure; D012039:Regional Blood Flow; D012680:Sensitivity and Specificity; D012771:Shock, Hemorrhagic
chemical_list: D002245:Carbon Dioxide