Effects of Dexamethasone and Oxymetazoline on “Postintubation Croup”: A ferret model

Abstract

Several studies recommend the use of steroids and racemic epinephrine for treatment of postintubation croup. Few controlled clinical or laboratory studies, however, support their effectiveness, and many questions remain about their use. The present study was undertaken to develop a reproducible animal model for postintubation croup and to perform initial controlled studies of the effects of dexamethasone (4 mg/kg) and the long-acting vasoconstrictor oxymetazoline (0.01 solution). An animal model for intubation trauma was developed with ten 10-week-old ferrets. Two models were created to reflect the spectrum of trauma—from simple mucosal contusion to mucosal ulceration. The first was to surgically strip mucosa in a circumferential manner at the level of the cricoid ring; the second was intubation trauma to the glottic and subglottic regions by use of a circular brush. Neither dexamethasone nor oxymetazoline had any statistically significant effect on subglottic edema in the mucosal stripping model. In the brush intubation model, oxymetazoline decreased subglottic edema at 2, 4, and 8 hours (P < 0.05), while dexamethasone and combination therapy decreased edema at 2,4, 8, and 24 hours (P < 0.05). At 24 hours, combination therapy was demonstrated to be the most effective in reducing subglottic edema. Oxymetazoline was as effective as dexamethasone and combination therapy at 2, 4, and 8 hours (P < 0.05). In this preliminary study, we have established the potential usefulness of the brush intubation model for the study of this disorder. This model was shown to have a reproducible and reversible lesion. The mucosal stripping model was not shown to have reversible lesion and—while further study needs to be performed—may only be useful as a model for very severe cases of this disorder. These initial studies also demonstrated high-dose dexamethasone and oxymetazoline to be effective in treatment of subglottic edema secondary to mucosal trauma. They also indicate that combination therapy is a more effective treatment than either agent alone.