LETTER TO THE EDITOR: Patients with Hemoglobinopathies Require Continuous Flow Supplemental Oxygen During Commercial Airline Flights

Patients with hemoglobinopathies are known to experience complications e.g. bone pain [1], splenic infarction [2] and osteonecrosis (avascular necrosis) of the hip (anecdotal report) subsequent to commercial airline flights. These complications are due to prolonged decrease in oxygen delivery at high altitudes. There is no study in the literature that has measured the oxygen saturation in these patients on commercial airline flights where planes ascend to altitudes of 30,000 feet or greater. At these altitudes, there is a low partial pressure of oxygen which is about a quarter of that at sea level. Humans would not be able to breathe without a pressurized environment and modern commercial jets are pressurized to an altitude of 5000-8000 feet. Ideally an airplane would be pressurized to ground level pressure (760 Torr). However this is not practical as the fuselage of a plane would have to be incredibly strong (and hence very heavy and expensive to fly) to withstand the outward force caused by 760 Torr while cruising at altitudes of 30,000 feet or greater [3]. At ground level, the partial pressure of oxygen is about 150 Torr or mm of mercury (20% of atmospheric pressure at 760 Torr). Inside a plane at cruising altitude oxygen partial pressure is reduced to about 125 Torr, In most people, this is a negligible change and their blood will remain fully saturated with oxygen at this pressure. This is not the case in patients with hemoglobinopathies in which tissue oxygen delivery is already compromised. We set out to determine the changes in oxygen saturation in seven patients with and without supplemental oxygen (continuous flow and pulse dose) provided during commercial airline travel. These patients with a mix of Hgb SS and SC were stable and without any underlying conditions. We provided them with a Sequal SmartPulseTM fingertip pulse oximeter to monitor oxygen saturation as well as with a SequalTM Eclipse 3 oxygen concentrator (Sequal Technologies, San Diego, California. Phone 858 202-3100). This oxygen concentrator is one of a few that are approved by the Federal Aviation Administration (FAA) for supplemental oxygen delivery on commercial