Pediatric emergency medicine trisk 0169 0169
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clinical circumstances where airway diameter may change over the course of
treatment (e.g., inhalational injury, angioedema), as a protective measure for
children at risk for aspiration, and in any child in whom underlying lung disease
may necessitate high ventilator pressures (e.g., bronchiolitis, status asthmaticus,
chronic lung disease). The risk associated with the use of cuffed ETTs is
excessive cuff pressures, which could lead to ischemia of the tracheal mucosa.
Various recommendations suggest that pressures higher than 20 to 30 cm H2 0
should be avoided. Measurement of cuff pressure can be achieved either through
listening for an air leak while applying positive pressure through the ETT, or by
using an ETT cuff manometer. The practice of “feeling” the cuff balloon has been
demonstrated to be inaccurate in assessing the cuff pressure.
ETT sizes are reported based on the internal diameter, measured in millimeters
(mm). Available sizes range from 2.0 mm (suitable for a preterm infant) to adult
sizes of 7.0 mm or more. Resistance to airflow as well as risk of tube obstruction
is increased in smaller tubes. Tube selection in pediatrics therefore aims to
balance these factors associated with smaller tubes, with the need to select a tube
that will pass easily through the vocal cords and not create excessive pressure on
the tracheal wall. Methods of selecting the appropriate tube size include use of a
length-based resuscitation tape, pediatric sizing programs available online or on
mobile devices, and use of an age-based formula. Each has been shown to be
effective, though inclusion of options for cuffed tube sizing is not offered in each.
3.0- or 3.5-mm uncuffed ETTs are normally used for term newborns. Smaller
tubes are used for premature newborns. For older children, the uncuffed ETT
sizing age-based formula: 4 + (age in years/4) has been shown to be accurate
until adult sizes of 7.0 (most females) to 8.0 (most males). For newer, low-profile
cuffed ETTs, selecting a tube one-half size smaller is recommended: 3.5 + (age in
years/4) . Regardless of the method chosen in selecting the initial tube size, it is
important to have additional tubes available, one size smaller in the event that
tube passage is difficult and one size larger if a large air leak results in inadequate
ventilation, despite inflation of the cuff where appropriate.
ETT stylets provide rigidity and shape to the ETT, facilitating tube guidance
through the glottic opening. Stylets have become particularly important with the
growing use of videolaryngoscopy (VL), during which tube passage is often done
indirectly, requiring manipulation around the curve of the tongue and then into
the glottic opening. Various stylet sizes exist to accommodate both pediatric and
adult-sized ETTs. The stylet should not project past the tip of the tube or through
the Murphy eye side hole. Bending the stylet over the adapter at the proximal end
of the tube prevents inadvertent movement during intubation.
