Assessing the Position of the Tracheal Tube: The Reliability of Different Methods

Anderson KH, Hald A Anaesthesia 1989 Pages 984-985

Various methods have been developed to confirm proper intubation of the trachea. This blind, randomized study evaluates some of these quantitatively and qualitatively. Twelve anaesthetists and 10 nurse anaesthetists participated as investigators. Forty patients had both their trachea and esophagus intubated. A procedure that included auscultation of the upper abdomen and lungs was 100% reliable independent of which tube was ventilated. Auscultation of the lungs resulted in a wrong conclusion 15% (6-30, 95% confidence limits) of the cases when the esophagus was ventilated: the sounds were misinterpreted as normal breath sounds. Suction on the tubes with a 60 ml syringe was also a reliable test. Attempts to aspirate air from an esophageal tube proved impossible. Other methods assessed were observation for condensation of water vapour (Always present during tracheal intubation, but also occurred 34/40 times [85%] during esophageal intubation), and abnormal movements of the upper abdomen: these were unreliable. Unrecognized intubation of the esophagus is a frequent cause of death or cerebral damage in anaesthesia. This investigation evaluated some easy and inexpensive methods to determine correct intubation of the trachea.