Effects of dexamethasone on laryngeal edema following short-term intubation.

Following short-term intubation for general anesthesia, respiratory difficulty may result from laryngeal or subglottic edema after extubation. We have hypothesized that this problem could be pretreated by administering a high-dose of dexamethasone intravenously before extubation. After glottic injuries were made under direct laryngoscopic view, intubation was performed and maintained for 1 hour in 33 rabbits. The rabbits were divided into 3 groups; dexamethasone (1 mg/kg) was administered to group 1(n=12) immediately after intubation and group 2(n=10) just before extubation; group 3(n=11) received normal saline, just before extubation. After extubation, subglottic excursion pressure was measured for 4 hours. 15 injured rabbit larynges and 3 normal ones were extracted for histologic section. 2 of 12 rabbits in group 1; 3 of 10 in group 2; and 5 of 11 in group 3, showed mild stridor after extubation(p>0.05). All rabbits developed maximum increase in subglottic pressure within 2 hours after extubation. Group 1 and 2 showed less increase in pressure compared to group 3(P<0.05), but here was no statistical difference between group 1 and 2(P>0.05). Histologic sections of the larynges showed less submucosal edema, including other changes in group 1 and 2, than in group 3(P<0.05). In conclusion, administering a high-dose of dexamethasone before extubation, is effective in prophylaxis and treatment of laryngeal injuries following short-term intubation in rabbits. This is especially true in edema.