Abstract
Undiagnosed oesophageal intubation during anaesthesia is a major cause of anaesthetic-related morbidity and mortality. A test was devised and evaluated to distinguish between placing an endotracheal tube in the trachea and in the oesophagus. The test involves threading a lubricated nasogastric tube through the endotracheal tube, applying continuous suction to the nasogastric tube and then attempting to withdraw the nasogastric tube. Four aspects distinguish an endotracheal tube in the trachea from one in the oesophagus: 1. the length of nasogastric tube inserted and the feel of the final obstruction to further insertion, 2. the ability to maintain unobstructed suction through the nasogastric tube, 3. the ease of withdrawal of the nasogastric tube during continuous suction, 4. the nature of any aspirate (i.e. mucus or gastric contents). An evaluation was performed on twenty patients in whom both the trachea and oesophagus were intubated simultaneously. In all twenty cases, each of the two endotracheal tubes was correctly identified as being either tracheal or oesophageal. The ability to maintain suction and the ease of withdrawal most clearly distinguished between the two positions.