Study objective: We evaluate changes in endotracheal tube intracuff pressures among intubated patients during aeromedical transport. We determine whether intracuff pressures exceed 30 cm H2O during aeromedical transport. Methods: During a 12-month period, a helicopter-based rescue team prospectively recorded intracuff pressures of mechanically ventilated patients before takeoff and as soon as the maximum flight level was reached. With a commercially available pressure manometer, intracuff pressure was adjusted to <= 25 cm H2O before loading of the patient. The endpoint of our investigation was the increase of endotracheal tube cuff pressure during helicopter transport. Results: Among 114 intubated patients, mean altitude increase was 2,260 feet (95% confidence interval [Cl] 2,040 to 2,481 feet; median 2,085 feet; interquartile range [IQR] 1,477.5 to 2,900 feet). Mean flight time was 14.8 minutes (95% Cl 13.1 to 16.4 minutes; median 13.5 minutes; IQR 10 to 16.1 minutes). Intracuff pressure increased from 28.7 cm H2O (95% Cl 27.0 to 30.4 cm H2O [median 25 cm H2O; IQR 25 to 30 cm H2O]) to 62.6 cm H2O (95% Cl 58.8 to 66.5 cm H2O; median 58; IQR 48 to 72 cm H2O). At cruising altitude, 98% of patients had intracuff pressures cm H2O, 72% had intracuff pressures >= 50 cm H2O, and 20% even had intracuff pressures >= 80 cm H2O. Conclusion: Endotracheal cuff pressure during transport frequently exceeded 30 cm H2O during aeromedical transport. Hospital and out-of-hospital practitioners should measure and adjust endotracheal cuff pressures before and during flight. [Ann Emerg Med. 2010;56:89-93.]