Detection of tracheal malpositioning of nasogastric tubes using endotracheal cuff pressure measurement

Background:  Insertion of a gastric tube (GT) in anaesthetized, paralyzed and intubated patients may be difficult. Tracheobronchial malposition of a GT may result in deleterious consequences. The purpose of this study was to determine the reliability of tracheal cuff pressure measurement to detect endobronchial malposition of GTs. We compared this new method with the measurement of exhaled CO2 through the GT. Methods:  Thirty patients under general anesthesia and orotracheal intubation were analysed. First, the cuff pressure of the low-volume endotracheal tube (ET; ID 7.0–8.5 mm) was increased to 40 cmH2O. Then, in a randomized fashion, the GT (18 Charriere) was inserted consecutively into the trachea and oesophagus or vice versa. Cuff pressure was monitored continuously while advancing the GT. Furthermore, a capnograph was connected to the gastric tube and the aspirated PCO2 was monitored. Results:  Advancement of the gastric tube into the oesophagus increased ET cuff pressure by 1 ± 1 cmH2O, while endotracheal placement of the GT increased cuff pressure by 28 ± 8 cmH2O (P 10 cmH2O in cuff pressure detected endotracheal malpositioning of the GT with 100% sensitivity and specificity. In 28 out of 30 cases, PCO2 increased by more than 2.6 kPa. Thus, the PCO2 approach failed to detect tracheal malpositioning in two cases resulting in a sensitivity of 93.3%. Conclusions:  In intubated patients, cuff pressure measurement during insertion of a gastric tube is a new, simple and reliable bedside method to detect endotracheal malpositioning of a GT.