Chest
Hypoxemia During Altitude Exposure: A Meta-Analysis of Chronic Obstructive Pulmonary Disease
Section snippets
METHODS
We evaluated mean hypoxemic responses from five published studies involving 71 patients with COPD.4, 5, 6, 7, 8 We searched for studies of patients with COPD published since 1966 that involved acute hypoxic exposure and also reported mean values for arterial blood oxygen tensions before and after exposure, barometric pressure (PB) or altitude conditions, fraction of inspired oxygen (FIO2) if other than ambient air, and results of spirometry, specifically FEV1.
We developed two measures of
RESULTS
Table 1 presents mean values for selected data from the five studies involving 71 patients. Age varied from 53 to 68 years in the studies. The weighted mean age equaled 64 ±5 years (n = 61). Mean values for FEV1 in the separate studies ranged from 0.975 to 1.400 L. Each study provided sufficient data for computation of linear and semilog slopes (Table 1, Fig 1).
Linear slope (Table 1), the change in PaO2 per unit change in P1O2 as defined in equation 1, correlated with FEV1 in a negative
DISCUSSION
We evaluated studies involving a specific disease entity with a finite range of inspired oxygen partial pressure. We do not expect the slope indices to correlate with FEV1 in normal subjects. The indices of hypoxia which we developed, however, may be applicable to other patient care settings involving changes in inspired oxygen partial pressure.
The present study provides further evidence of the utility of FEV1 as a predictor of PaO2 during altitude exposure in COPD patients.8 In COPD and other
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2018, Respiratory MedicineCitation Excerpt :The evidence surrounding which ILD patients to refer for HCT is currently lacking. Predictive equations are alternatives that have been developed for use in clinical practice, to predict PaO2 at altitude [10,14–18], but have been developed almost exclusively using patients with COPD and their role in patients with ILD has not been fully defined. The primary aim of this study was to explore the concordance of existing published equations, used to predict in-flight hypoxaemia, with the outcome of HCT in patients with ILD.
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2011, Sleep MedicineCitation Excerpt :According to the British Thoracic Society (BTS) recommendations published in 2002, if the resting oxygen saturation (SpO2) exceeds 95%, further assessment or supplemental in-flight oxygen is not required and if resting SpO2 is between 92% and 95% hypoxic challenge is needed only if an additional risk factor is present [3]. Most studies investigating the risk of in-flight hypoxemia have been carried out on subjects with COPD [8–10], interstitial and restrictive lung disease [10,11]. The hypoxic challenge test (HCT), also known as hypoxia inhalation test, is performed as a part of the pre-flight assessment in many centres [12,13].
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2008, FMC Formacion Medica Continuada en Atencion Primaria
Supported by WRAMC DCI protocol No. 1724.
The opinions contained herein represent solely the views of the authors and are not to be construed as representing the views of the Department of Defense or the Department of the Army.
Presented at the annual meeting of the American Thoracic Society, May 1992, Miami Beach, Fla.
Manuscript received January 27; revision accepted June 26.