Last weekend, my wife and I went to Trang, a province in Southern Thailand. The quickest way to get there is by plane. I was confident that my blood oxygen saturationBlood Oxygen Saturation (SpO2) The oxygen saturation (SpO2) of a person's blood is defined as a percentage of the maximum amount (100%) of oxygen it can transport. A healthy person's SpO2 percentage should be between 96% and 99%. - Source: What is oxygen saturation (SpO2)? What is the normal range for SpO2??. Retrieved 11 November 2022, from ihealthlabs.com (SpO2Blood Oxygen Saturation (SpO2) The oxygen saturation (SpO2) of a person's blood is defined as a percentage of the maximum amount (100%) of oxygen it can transport. A healthy person's SpO2 percentage should be between 96% and 99%. - Source: What is oxygen saturation (SpO2)? What is the normal range for SpO2??. Retrieved 11 November 2022, from ihealthlabs.com) would be fine during the flight. At the same time, I was very curious to see how my SpO2 would be affected by being up in the air.

I underwent successful BPABalloon Pulmonary Angioplasty Balloon pulmonary angioplasty, or BPA for short, is a technique for widening narrowed or blocked blood vessels in the lungs of CTEPH patients. Small balloons attached to a catheter restore blood flow to areas of the lungs that do not receive blood due to the disease.  When successful, BPA eliminates or reduces shortness of breath, increases exercise tolerance and quality of life, and extends life expectancy. treatment (four interventions) in Japan in late 2022, and now I feel like a new person with new lungs. I no longer require supplemental oxygen while traveling on a plane.

To satisfy my curiosity, I had my trusted pulse oximeter with me and checked SpO2 several times during the flight. All checks while seated.

Here is what happened.

Nothing dramatic!

Pulse oximeter in the author's hand showing and SpO2 of 97%.
My SpO2 was between 96% and 98% at the gate and while the aircraft was taxiing to the take-off position. – Photo Gregor Rasp

My SpO2 was between 96% and 98% at the gate and while the aircraft was taxiing to the take-off position.

Several minutes into the flight, the aircraft was still climbing, and SpO2 gradually began to slip. First to 95% … then 90%, bottoming at 88%.

During the flight at cruising altitude, SpO2 varied between 89% and 91%, with a trend toward the upper value.

Two pulse oximeter in the author's hand showing different SpO2 percentages, 95% and 90% respectively.
In-flight SpO2 percentages. – Photos by Gregor Rasp

As soon as the airplane began to descend, SpO2 immediately started to rise. First to 91% and then quickly to 95%-96%.

A few days later, I saw similar values and changes in SpO2 percentages on the return flight.

I felt completely normal at all times.

During the flight, I felt completely normal. I had no shortness of breath, lightheadedness, chest pressure, irregular heartbeat (palpitations), etc.

Some background information.

It was a relatively short flight, under 2 hours in duration. Flight duration matters, and SpO2 tends to reach lower percentages on longer flights. [1]

The pressure in the cabin of commercial aircraft is always lower than at sea level. Typically, an atmospheric pressure corresponding to an altitude of 2,438 m (8,000 feet) is maintained. The lower atmospheric pressure results in 15% breathable oxygen compared to 21% at sea level, leading to lower oxygen saturation in the blood of those aboard the aircraft. In contrast to healthy individuals, low SpO2 percentages are typical in patients with CTEPHChronic Thromboembolic Pulmonary Hypertension CTEPH is short for chronic thromboembolic pulmonary hypertension, a rare form of high blood pressure in the lungs caused by blood clots or narrowed blood vessels. High blood pressure in the lungs is often also called pulmonary hypertension. (or PHPulmonary Hypertension (PH) High pressure in the blood vessels leading from the heart to the lungs is called pulmonary hypertension. The arteries in the lungs and the right side of the heart are affected by pulmonary hypertension. If untreated, the right side of the heart will weaken over time, eventually leading to heart failure and death. The WHO has defined five distinct groups of pulmonary hypertension, each with a different cause. CTEPH is a form of PH (WHO group 4). - References: mayoclinic.org and cdc.gov in general) when traveling by air. CTEPH (PH and lung or heart) patients are at increased risk for in-flight complications and should consult their physician before flying. [1] Your doctor may recommend supplemental oxygen while traveling on a plane.

Important: Please understand that every person is different, which also applies to the oxygen saturation of the blood. Your experience might be entirely different from mine.

References

[1] Ekici B. (2021). Can a patient with pulmonary hypertensionPulmonary Hypertension (PH) High pressure in the blood vessels leading from the heart to the lungs is called pulmonary hypertension. The arteries in the lungs and the right side of the heart are affected by pulmonary hypertension. If untreated, the right side of the heart will weaken over time, eventually leading to heart failure and death. The WHO has defined five distinct groups of pulmonary hypertension, each with a different cause. CTEPH is a form of PH (WHO group 4). - References: mayoclinic.org and cdc.gov travel safely by plane? Anatolian journal of cardiology, 25(Suppl 1), 29–30. https://doi.org/10.5152/AnatolJCardiol.2021.S111.