title: Reliability of capnography in identifying esophageal intubation with carbonated beverage or antacid in the stomach.
abstract: To evaluate the reliability of capnography in identifying esophageal intubation in the presence of a carbonated beverage in the stomach, we first investigated the amount of CO2 released from different carbonated beverages and antacids in a simulated stomach; next we measured the end-expired CO2 level during esophageal ventilation with a carbonated beverage in the stomachs of six swine. CO2 levels of approximately 20% were consistently observed in all carbonated beverages. The CO2 levels obtained with sodium bicarbonate, Maalox, and sodium citrate were 19.3%, 2.0%, and 0%, respectively. CO2 waveforms were observed during esophageal ventilation in five of six animals after intragastric administration of a carbonated beverage. An end-expired CO2 level of 2.5% or more was observed in two swine. The highest end-expired CO2 level measured was 5.3%. We conclude that although capnography is convenient and effective, it lacks all the attributes of an ideal monitor for detecting esophageal intubation.
authors.affiliation: Department of Anesthesia, University of Iowa, College of Medicine, Iowa City 52242.
authors.forename: S T
authors.initials: ST
authors.lastname: Sum Ping
authors.forename: M P
authors.initials: MP
authors.lastname: Mehta
authors.forename: T
authors.initials: T
authors.lastname: Symreng
mesh_terms: D000818:Animals; D000863:Antacids; D002245:Carbon Dioxide / Q000032:analysis* / Q000378:metabolism; D002253:Carbonated Beverages; D004947:Esophagus; D005766:Gastrointestinal Contents; D007440:Intubation; D012121:Respiration, Artificial; D013552:Swine
chemical_list: D000863:Antacids; D002245:Carbon Dioxide