Postextubation Stridor: What’s All That Beyond the Noise?

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Postextubation stridor (PES) is an often encountered and unintended complication of intubation for mechanical ventilation in the ICU (1). The occurrence rate of PES varies from anywhere between 3.5% and 30%, the wide variation being mainly accounted for by heterogeneity in the study populations and diagnostic criteria. The term “PES” is used to imply extrathoracic airway obstruction from laryngeal or subglottic edema. In some instances, PES may also result from poor clearance of secretions, brainstem dysfunction, vocal cord paralysis, vocal cord granuloma, or subglottic stenosis. Occasionally, an otherwise subclinical upper airway obstruction may be aggravated by increased respiratory effort causing wide intrathoracic pressure changes due to coexistent pulmonary disease or cardiac dysfunction.
PES is associated with increased morbidity including prolonged hospital stay and risks of reintubation, airway trauma and nosocomial infection (2). Therapies to treat PES are often associated with their own risks and expense. Various treatment options for PES include vasonstrictor nebulizations, mixture of helium and oxygen, and corticosteroids. Because of their efficacy in treating viral laryngotracheobronchitis (3, 4), corticosteroids have often been used in either treatment or prevention of PES in adults, children, and neonates. A recent Cochrane review showed benefit of corticosteroids in neonates at high risk for PES but not in children outside the neonatal period (5). In adults with high risk for PES, there is benefit in using multiple dose steroids 12–24 hours prior to extubation (5). A single-center randomized controlled trial (RCT) showed that parenteral administration of multiple doses of steroids is effective in prevention of PES in children (6).
Even a short duration of systemic steroid use for prevention or treatment of PES is often associated with side effects like hypertension, hyperglycemia, and gastrointestinal bleeding (6, 7). To minimize these adverse effects, interest in the use of inhaled steroids has been generated. Short-term inhaled steroids have been shown to be effective in the treatment of viral laryngotracheobronchitis without the side effects of the systemic therapy (8, 9). Inhaled steroids make pharmacologic sense since the droplet size for airway deposition is between 2 and 5 μm and most nebulizers generate a particle size of 1–5 μm (10) ensuring adequate topical delivery to the airways provided there is no supraglottic obstruction. Whether inhaled steroids are as efficacious as systemic steroids in treating PES is yet to be proven.
Although clinically similar in symptomatology, the pathophysiology of PES may be different from viral laryngotracheobronchitis. Unlike stridor from croup which is infection-associated edema and inflammation of the subglottic larynx and trachea, PES is a manifestation of trauma-associated laryngeal edema with vocal cord ulceration and mucosal disruption (11). PES may have coexisting supraglottic, glottic, and subglottic components of trauma-associated inflammation.
In this issue of Pediatric Critical Care Medicine, Prasertan et al (12) report the results of their well-designed, double-blind RCT with the primary objective of evaluating the efficacy of a single dose nebulized fluticasone propionate compared with placebo immediately after extubation in prevention of PES. Occurrence of PES within 6 hours after extubation was the primary outcome. The authors found no benefit of nebulized fluticasone over placebo. Although not the primary endpoint of the study, the time to start noninvasive positive pressure ventilation, in those that needed it, was longer in the fluticasone group especially in patients who were emergently intubated. This is suggestive of corticosteroids having had an ameliorating effect on progression of postextubation obstruction in this group of patients. Also, the modified Westley scores at 30 and 60 minutes in the control group were significantly higher than in the treatment group, respectively, even though the occurrence of PES at 6 hours was similar.

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