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A Bronchoscopic, Computer‐assisted Examination of the Changes in Dimension of the Infant Tracheal Lumen with Changes in Head Position: Implications for Emergency Airway Management

Background Resuscitation guidelines caution against extreme extension or flexion of an infant's head because tracheal obstruction may occur. No data support this recommendation. The authors therefore examined the dimensions of the tracheal lumen in neutral, extended, and flexed head positions in infants undergoing general endotracheal anesthesia for elective surgery. Methods Eighteen healthy full‐term infants were studied. A flexible fiberoptic bronchoscope was passed through a previously inserted endotracheal tube and positioned above the cricoid cartilage. Video recordings were taken in each of three head positions. Recordings were analyzed by an investigator blinded to head position. A computer‐digitized technique was used to measure anterior‐posterior and lateral dimensions and cross‐sectional area. Data were analyzed using paired t tests and sign tests. Results No significant differences in mean tracheal dimensions with changes in head position were found. No infant had complete tracheal obstruction. Infants were equally as likely to have a small increase as they were to have a small decrease in tracheal dimension with changes in head position. Conclusions Despite the belief that infants and neonates have obstruction at the level of the trachea with extreme positions of the head, the authors were unable to demonstrate this phenomenon.