Studies comprising patients with chronic obstructive pulmonary disease (COPD) for prediction of hypoxaemia during air travel
| Author [ref.] | Year | Patients | Test/condition used | Results |
| Gong [33] | 1984 | 22 moderate COPD | HCT | Sea level PaO2 predicted acute resting altitude PaO2 |
| Dillard [51] | 1989 | 18 severe COPD | Hypobaric chamber | Ground PaO2 correlated with expected altitude PaO2, combination of FEV1 and ground PaO2 improved prediction of PaO2 at 8000 ft |
| Schwartz [52] | 1984 | 13 severe COPD | Inflight ABGs at 1650 m and 2250 m | PaO2 measured <2 h before the flight in room air or a 17.2% oxygen mixture correlated with PaO2 at 1650 m. PaO2 measured several weeks before flight did not correlate with any in-flight measurements |
| Berg [31] | 1992 | 18 severe COPD | Hypobaric chamber | Oxygen supplementation via nasal cannula or Venturi mask corrects altitude hypoxaemia |
| Christensen [30] | 2000 | 15 severe COPD | HCT | Pre-flight PaO2 >70 mmHg, FEV1 or TLCO values do not predict altitude hypoxaemia. Light exercise may provoke hypoxaemia and there was a correlation between aerobic capacity and altitude PaO2 |
| Robson [53] | 2000 | 20 COPD (15 severe) and 8 other RD | HCT | Altitude PaO2 could not be predicted from either FEV1 or pre-test SpO2 |
| Seccombe [35] | 2004 | 10 COPD and 15 ILD | HCT with 50-m walk test | Resting sea level PaO2 is poor for predicting the hypoxaemic response in both COPD and ILD groups. Means of PaO2 of both groups fell below recommended levels at both resting and when walking during HCT |
| Akero [34] | 2005 | 18 COPD | In-flight ABG | Significant desaturations were observed during flight, which were worsened with activity. A pre-flight PaO2 >70 mmHg did not predict in-flight hypoxaemia. Aerobic capacity showed the strongest correlation with in-flight PaO2 |
| Chetta [54] | 2007 | 15 COPD and 15 ILD | HCT and 6MWT | SpO2 in 6MWT can predict oxygen desaturation during HCT |
| Kelly [55] | 2008 | 13 severe COPD | In-flight SpO2, post-flight HCT and 6MWT | Significant desaturations were observed during flight, which were worsened with activity. HCT SpO2 was well correlated with in-flight SpO2. Resting PaO2 and the post-flight 6MWT result did not correlate with in-flight SpO2 |
| Akero [50] | 2008 | 100 COPD | HCT | Pre-flight SpO2 does not help to discriminate patients adequately for in-flight O2 supplementation. 30% of patients with pre-flight SpO2 >95% and 67% of patients with pre-flight SpO2 between 92–95% and without additional risk factors dropped PaO2 below 50 mmHg during HCT |
| Robson [49] | 2008 | 74 COPD and 44 other RD | HCT | Desaturation during HCT cannot be predicted reliably from either FEV1 or sea level SpO2. All patients with sea level SpO2 >95% maintained O2 saturation >90% during HCT. One-third of patients with sea level SpO2 between 92–95% and with no risk factor desaturated during HCT |
| Kelly [56] | 2009 | 18 severe COPD | Mount Hutt (2086 m altitude) | Ascent from sea level to altitude caused significant hypoxaemia (PaO2 75±9 versus 51±6 mmHg, respectively), and worsened during walk test (41±7 mmHg) which was partially reversed by supplemental oxygen (64±9 mmHg). KCO correlated both with resting altitude SaO2 and exercise PaO2 |
| Edvardsen [57] | 2012 | 100 severe COPD | HCT and 6MWT | An algorithm was constructed using a combination of resting and 6MWT SpO2. Resting SpO2 >95% combined with 6MWT SpO2 >84% had a sensitivity of 100% and specificity of 80% for fitness to fly |
| Edvardsen [58] | 2013 | 82 moderate-to-severe COPD | HCT and pre- and post-flight symptom questionnaire | Post-flight questionnaire results showed that there was no difference in HCT PaO2 between patients with and without symptoms; however, planned use of in-flight supplemental oxygen in patients with HCT PaO2 <50 mmHg resulted in a lower frequency of respiratory symptoms |
RD: respiratory disease; ILD: interstitial lung disease; HCT: hypoxic challenge test; ABG: arterial blood gas; 6MWT: 6-min walk test; SpO2: arterial oxygen saturation measured by pulse oximetry; PaO2: arterial oxygen tension; FEV1: forced expiratory volume in 1 s; TLCO: transfer factor of the lung for carbon monoxide; KCO: transfer coefficient of the lung for carbon monoxide.