Pediatric airway anatomy may not be what we thought: implications for clinical practice and the use of cuffed endotracheal tubes

One of the long held tenets of pediatric anesthesia has been the notion that the pediatric airway is conical shape with the narrowest area being the cricoid region. However, recent studies using radiologic imaging techniques (magnetic resonance imaging and computed tomography) or direct bronchoscopic observation have questioned this suggesting that the narrowest segment may be at or just below the glottic opening. More importantly, it has been clearly demonstrated that the airway is elliptical in shape rather than circular with the anterior-posterior dimension being greater than the transverse dimension. These findings coupled with the development of a new generation of cuffed endotracheal tubes (ETTs) with a thin, polyurethane cuff have caused a transition in the practice of pediatric anesthesiology with an increased use of cuffed ETTs, even in neonates and infants. The following article reviews the historical data leading to the assumption that the pediatric airway is conical as well as the more recent imaging and direct bronchoscopic observational studies which refute this tenet. The transition to the use of cuffed ETTs is discussed and potential advantages presented in both the operating room and the intensive care unit. Issues regarding the monitoring of intracuff pressure and techniques to limit potential morbidity related to a high intracuff pressure are outlined.