Introduction Air medical services routinely transport patients who are intubated and mechanically ventilated. Transporting this patient population is safe but patients subject to changes in barometric pressure in flight. Aircraft used typically maintain a cabin pressures of 3000 to 7000 feet above sea level. This compares to commercial aircraft that maintain cabin pressures of 5000 to 8000 feet. A known volume of gas will expand as the ambient pressure decreases. If the gas cannot expand, pressure exerted by the gas in an enclosed space will increase. An aircraft cabin with an ambient pressure of 3000 to 7000 feet altitude results in a 9 to 23% decrease in ambient pressure compared to sea level. Tracheal tube cuffs are subject to changes in ambient pressure that occur in transport. Tracheal tube cuffs minimize the risk of tracheal mucosal injury, but high pressures occur. A recent series of intubated adult patients undergoing transfer by helicopter showed that 58% had initial pressures greater than 40 cm H2O . A subsequent study revealed pressures exceeding 40 cm H2O in two thirds of patients and 30 cm H2O in nearly three quarters. There is a risk because tracheal mucosa blood flow is compromised at 30 cm H2O, and ceases at lateral wall pressures of 50 cm H2O. These high pressures can result in complications ranging from sore throat to major complications such as tracheal ischemia and fistula formation. To avoid tracheal injury and related complications, tracheal tube cuff pressures should be maintained at less than 30 cm H2O.