Updated recommendations on respiratory specialist referral and the need for in-flight oxygen are made in a new clinical statement on air travel for passengers with respiratory disease.
Published in Thorax, the statement developed by the British Thoracic Society (BTS) says several developments have taken place in the area of air travel-related hypoxia since the last guidelines were published in 2011, “requiring a new look at the advice for healthcare professionals”.
As such, the new guidance compiled by an expert group of secondary and primary healthcare professionals spanning paediatrics, nursing, respiratory physiology, and physiotherapy, focuses on three key areas: the role of the hypoxic challenge test (HCT) to predict hypoxaemia during flight; how respiratory conditions respond differently to altitude; and logistics of air travel with equipment such as portable oxygen concentrators (POCs).
The guidelines stress that all patients should undergo careful initial evaluation – with history and physical examination – by a competent clinician, who should review symptoms, baseline exercise capacity, recent exacerbation history, treatments and previous experience of air travel.
Those whose screening raises concerns should be referred to a respiratory specialist, who might advise HCT if appropriate. While HCT is not able to predict respiratory symptoms during air travel, limited evidence does suggest that those who desaturate during the test, in-flight oxygen can help to alleviate symptoms.
According to the guidelines, patients who shouldn’t need HCT include: those with stable disease who have previously undergone the test; COPD patients with baseline SpO2 ≥95% and either MRC score 1-2 or desaturation to no less than 84% during walking tests; those previously unable to tolerate air travel; and preterm infants who have not reached their due date at the time of travel.
Those is should be considered include: COPD patients with resting SpO2 of ≤95%, MRC score 3 or greater, or desaturation to <84% walking tests; infants and children with a history of neonatal respiratory problems; adults and children with severe asthma; ILD patients whose SpO2 drops to less than 95% on exercise, and whose resting sea level arterial oxygen tension (PaO2) is ≤9.42 kPa or whose TLCO is ≤50%; those with severe respiratory muscle weakness or chest wall deformity in whom forced vital capacity (FVC) is less than 1 L; patients with existing or previous hypercapnia and those at risk of hypercapnia; and patients with a history of type 2 respiratory failure already on long-term oxygen therapy at sea level.
In-flight oxygen is then only recommended if HCT results show a PaO2 of less than 6.6 kPa (<50 mm Hg) or SpO2 of less than 85%.