The "Safe Index" Considering Body Surface Area for Prolonged Dexamethasone Regimen in Airway Control After Head and Neck Microsurgical Reconstruction.

[BACKGROUND] Dexamethasone (Dexa) is frequently administrated to patients receiving head and neck microsurgical reconstruction with nasotracheal intubation postoperatively for airway control. Infection is the greatest concern when prolonging the treatment course. We aimed to find out the relationship between flap infection and the safe dose of Dexa.

[MATERIALS AND METHODS] A retrospective review of enrolling total 156 patients underwent microsurgical free flap reconstruction for head and neck cancers with nasotracheal intubation from December 2015 to December 2016 was conducted. Among them, 139 patients had received prolonged Dexa treatment course (>2 days). Safe index was then defined as the total amount of used Dexa (in milligrams) over body weight (in kilograms), body mass index (in kilograms per square meter) and body surface area (BSA, in square meter). Statistics were performed for the cutoff level of the safe index and to find out the independent risk factors.

[RESULTS] The cutoff level of the safe index was 0.76 for body weight group, 2.28 (10-3 m2) for body mass index group, and 33.84 mg/m2 for BSA group. Safe index for BSA group also outweighed other risk factors in multivariant analysis (odds ratio = 6.242, 95% confidence interval = 2.292-17.002, P = 0.000), which is the only independent risk factors for flap infection in our cohort.

[CONCLUSIONS] Throughout our study, the "safe index" helps clinician easily predict flap infection risk when using Dexa as the medication for airway control after head and neck microsurgical reconstruction.