21 March 2019 Every year, millions of people travel all around the world on commercial planes. With the increase in average age, the number of comorbidities increases and, consequently, so does the risk of hypoxia (low oxygen content in the tissues) occurring during flight - during which time the percentage of oxygen in the inspired air is 15%. What is a hypoxia altitude simulation test? The hypoxia altitude simulation test simulates, in sea-level laboratory conditions, the hypoxia resulting from being at an altitude of 2,438 metres. To do this it uses a gaseous mixture containing 15% oxygen. How is the hypoxia altitude simulation test carried out? The test involves asking people to breathe in the hypoxic gas mixture for around 20 minutes, with continuous monitoring by pulse oximetry. Who is the hypoxia altitude simulation test suitable for? The test can be indicated for individuals with peripheral oxygen saturation of between 92% and 95% who have at least one of the following risk factors: Dyspnoea or thoracic pain during a previous aeroplane journey; Inability to walk 50 metres without dyspnoea occurring; Hypercapnia (increased carbon dioxide in blood); Forced expiratory volume in one second (FEV1) of <50% of that expected; Reduction of the alveolar-capillary transfer of carbon dioxide; Restrictive lung diseases; Cerebrovascular or cardiac disease; Exacerbation of chronic lung disease within the 6 weeks prior to travel; Pulmonary hypertension. What is the purpose of the hypoxic altitude simulation test? This test determines whether or not additional oxygen is required during a flight . Ideally, it should take place between 1 and 14 days before the planned air travel. Patients with oxygen saturation greater than 95% will be able to travel without additional oxygen . Therefore, they do not need to be subjected to additional examinations. However, for those with saturation of less than 92% or who are receiving long-term oxygen therapy, additional oxygen is formally indicated for travel. This article was written with the support of physicians and other clinical professionals from the Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
