Continuous spirometry for detection of double-lumen endobronchial tube displacement.

Flow-volume and pressure-volume loops were measured with continuous spirometry in 49 patients in whom the trachea was intubated "blindly" with a double-lumen endobronchial tube for thoracic surgery. Nineteen endobronchial tubes were malpositioned by fibreoptic bronchoscopic criteria; 63% of these were suspected because of the configuration of the spirometric loops. During positioning of the patient and during operation, 34.7% of the endobronchial tubes migrated from the initially correct or corrected position. The secondary displacements were identified by abnormal loop configurations and confirmed with fibreoptic bronchoscopy. Continuous spirometric monitoring is helpful in detecting endobronchial tube displacement during intubation and surgery.