The endotracheal tube air leak test does not predict extubation outcome in critically ill pediatric patients

Abstract

Objective: Endotracheal tube air leak pressures are used to predict postextubation upper airway compromise such as stridor, upper airway obstruction, or risk of reintubation. To determine whether the absence of an endotracheal tube air leak (air leak test >/=30 cm H2O) measured during the course of mechanical ventilation predicts extubation failure in infants and children.

Design: Prospective, blinded cohort.

Setting: Multidisciplinary pediatric intensive care unit of a university hospital.

Patients: Patients younger than or equal to 18 yrs and intubated >/=24 hrs.

Interventions: The pressure required to produce an audible endotracheal tube air leak was measured within 12 hrs of intubation and extubation. Unless prescribed by the medical care team, patients did not receive neuromuscular blocking agents during air leak test measurements.

Measurements and main results: The need for reintubation (i.e., extubation failure) was recorded during the 24-hr postextubation period. Seventy-four patients were enrolled resulting in 59 observed extubation trials. The extubation failure rate was 15.3% (9 of 59). Seven patients were treated for postextubation stridor. Extubation failure was associated with a longer median length of ventilation, 177 vs. 78 hrs, p = 0.03. Extubation success was associated with the use of postextubation noninvasive ventilation (p = 0.04). The air leak was absent for the duration of mechanical ventilation (i.e., >/=30 cm H2O at intubation and extubation) in ten patients. Absence of the air leak did not predict extubation failure (negative predictive value 27%, 95% confidence interval 6-60). The air leak test was >/=30 cm H2O before extubation in 47% (28 of 59) of patients yet 23 patients extubated successfully (negative predictive value 18%).

Conclusions: An endotracheal tube air leak pressure >/=30 cm H2O measured in the nonparalyzed patient before extubation or for the duration of mechanical ventilation was common and did not predict an increased risk for extubation failure. Pediatric patients who are clinically identified as candidates for an extubation trial but do not have an endotracheal tube air leak may successfully tolerate removal of the endotracheal tube.

Figure 1

Length of mechanical ventilation (LOV) is divided into three known risk groups LOV ≤ 2 days, LOV between 2 and 10 days, and LOV≥10 days. The percentage of patients who failed extubation (i.e., were reintubated within 24 hours) increases as the length of ventilation increases (p=0.3).