Endotracheal Tubes and Cuffs for Infants and Children August 2020
Endotracheal tube sizing, and endotracheal tube cuffs, have been updated in the section Endotracheal Tubes and Cuffs, under the section ENDOTRACHEAL TUBE EQUIPMENT. For premature infants, use an uncuffed endotracheal tube. For fullterm infants and children to age 12, use a cuffed endotracheal tube. Tube size for children ≥ 2 years old is estimated by the formula: (Age in years/4) + 3.5
Garth Meckler, MD, MPH
Children have distinct characteristics that result in differences in the approach to supporting oxygenation and ventilation compared to adults. In addition, there are significant physiologic, anatomic, and equipment differences between children and adults that must be considered when managing the pediatric airway. The presentation of a critically ill child requiring significant support of oxygenation or ventilation, potentially leading to endotracheal intubation, is relatively uncommon compared to adults.1–4 This chapter presents some unique characteristics of pediatric respiratory physiology as well as distinct anatomic characteristics of the pediatric airway. It also discusses strategies for effective airway management, including strategies to select equipment and dose drugs with the goal to minimize errors.5
Due to a higher metabolic rate, oxygen consumption is increased in children, especially in infants. As a result, children are vulnerable to rapid desaturation when oxygenation or ventilation is reduced. Children have relatively small-volume lungs with small functional residual capacities, and tachypnea is the initial response to most insults to oxygenation and ventilation. This also translates into a reduced oxygen reservoir, which decreases the length of safe apnea time after neuromuscular blockade, even when preoxygenation is optimized. Therefore, be prepared to support oxygenation with bag-mask ventilation (BMV) before an intubation attempt, while awaiting the onset of induction and paralysis, and during the apneic period after paralytics have been administered. Below an oxygen saturation of 90%, desaturation is particularly rapid.6 The vast majority of children are easily bag ventilated when the proper technique is used, even when partial obstruction is present. The key is anticipation and early use of good BMV.
Children can develop gastric distention from swallowing air during distress as well as insufflation during BMV. Gastric distention can further compromise functional residual capacity, tidal volume, and ventilation. Gastric insufflation is generally a more significant problem the younger the age of the child. Proper BMV technique can reduce the risk, and early placement of an orogastric or nasogastric tube may help. Gastric tubes are also recommended to minimize the risk of reflux from an incompetent gastroesophageal junction, but the incidence of aspiration in children appears to be quite low, even in emergent intubation.
Children have a proportionally larger extracellular fluid compartment than adults. This results in a quicker onset and shorter duration of action of drugs and may require higher doses per kilogram for many of the drugs used to facilitate rapid-sequence intubation.