Hypoxic challenge flight assessments in patients with severe chest wall deformity or neuromuscular disease at risk for nocturnal hypoventilation

Abstract

Background: The British Thoracic Society (BTS) recommendations for patients with respiratory disease planning air travel suggest that an oxygen saturation (SaO 2 ) .95% precludes the need for any further assessment of the need for supplemental oxygen during flight. A hypoxic challenge test (HCT) is recommended for patients with a resting SaO 2 between 92% and 95% with an additional risk factor, including kyphoscoliosis (KS) or neuromuscular disease (NMD). However, this recommendation was based on very few data. Patients and methods: HCTs were performed on 19 adult patients with KS and/or NMD (age 22-73 years, forced expiratory volume in 1 s (FEV 1 ) 0.76, forced vital capacity (FVC) 0.92, SaO 2 95%, partial pressure of arterial CO 2 (PaCO 2 ) 5.7 kPa) who were at risk for nocturnal hypoventilation. 15 were home ventilator users. Arterial blood gas measurements were made before and at the end of the hypoxic challenge. Results:The results of HCTs show that the majority (15 of 19) of this cohort of patients met the criteria suggested by the BTS Standards of Care Committee for in-flight oxygen regardless of baseline SaO 2 . Conclusions: This finding suggests that all patients with severe extrapulmonary restrictive lung disease should undergo assessment with HCT prior to air travel. The study confirms that even patients with a resting saturation of .95% can desaturate significantly during hypoxic challenge. This study does not address the question of whether desaturation at altitude has any adverse consequences for patients. A decision as to whether it is safe for a patient to fly should be made by an experienced clinician and based on a number of factors, which should include previous travel experience, the patient's overall condition and the results of an HCT.In 2002 the British Thoracic Society (BTS) Standards of Care Committee published recommendations for managing patients with respiratory disease planning air travel.1 It was recommended that assessment should include pulse oximetry, with arterial blood gas analysis being preferred if hypercapnia is suspected. Supplemental oxygen during flight is not recommended for patients with a resting oxygen saturation (SaO 2 ) at sea level of . 95% or for those with a saturation between 92% and 95%, without an additional risk factor. For those with an SaO 2 between 92% and 95% at sea level and an additional risk factor, a hypoxic challenge test (HCT) is recommended. If the SaO 2 is ,92%, supplemental oxygen should be advised for use throughout flight. Preflight assessment is recommended for a variety of specific groups of patients, including those with severe restrictive disease (including chest wall and respiratory muscle disease) with hypoxaemia and/or hypercapnia; these patients should therefore have an HCT if their resting saturation is (95%. If during the hypoxic challenge the partial pressure of arterial O 2 (PaO 2 ) falls below 6.6 kPa, supplemental oxygen is recommended during flight; if it remains above 7.4 kPa, supplemental oxygen is not needed, with val...

Managing passengers with stable respiratory disease planning air travel: British Thoracic Society recommendations

“…A recent study205 examined 21 patients (16 with idiopathic kyphoscoliosis and five with neuromuscular disease). Thirteen were male and the median age was 58 years (range 22–73).…”

Oxygen or ventilation during flight for patients with neuromuscular disease?

“…We read with great interest the paper by Mestry et al 1 which analysed hypoxic challenge flight assessments in patients with restrictive disorders. In their study they dispute the current British Thoracic Society recommendations, demonstrating that, in this subgroup, all patients planning air travel should have a pre-flight evaluation because, even in patients with normal baseline oxygen saturation (Sa o 2 ), arterial oxygen tension (Pa o 2 ) can fall below 6.6 kPa during hypoxic challenge.…”

Pre‐flight assessment in patients with obesity hypoventilation syndrome

“…According to the Aerospace Medical Association guideline published in 2003, baseline PaO 2 is considered the best predictor of altitude PaO 2 , but our data do not support this observation. Several previous studies in both obstructive and non‐obstructive lung diseases have also shown that baseline PaO 2 does not reliably predict the degree of desaturation during HCT …”