PT  - JOURNAL ARTICLE
AU  - Christine Costa
AU  - André Barros
AU  - João Valença Rodrigues
AU  - Richard Staats
AU  - Mariana Alves
AU  - Pilar Cardim
AU  - Carlos Lopes
AU  - Cristina Barbara
AU  - Luís F. Moita
AU  - Susana Moreira
TI  - Comparison Between Normobaric Hypoxia Altitude Simulation Test and Altitude Hypoxia Predictive Equations in Cystic Fibrosis Patients
AID  - 10.1101/570754
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 570754
4099  - http://biorxiv.org/content/early/2019/03/09/570754.short
4100  - http://biorxiv.org/content/early/2019/03/09/570754.full
AB  - Background: The Hypoxia Altitude Simulation Test (HAST) is the Gold Standard to evaluate hypoxia in response to altitude and to decide on in-flight requirements for oxygen supplementation. Several equations are available to predict PaO2 in altitude (PaO2alt), but it remains unclear whether their predictive value is equivalent. We aimed to compare the results obtained by the available methods in a population of cystic fibrosis (CF) adults.Methods: Eighty-eight adults (58 healthy controls and 30 CF patients) performed a spirometry followed by an HAST. HAST results were compared with the predicted PaO2alt made by five equations: 1st: PaO2alt= 0,410 x PaO2ground + 1,7652; 2nd: PaO2alt= 0,519 x PaO2ground + 11,855 x FEV1 (L) − 1,760; 3rd: PaO2alt= 0,453 x PaO2ground + 0,386 x FEV1 (%) + 2,44; 4th: PaO2alt= 0,88 + 0,68 x PaO2ground; 5th: PaO2alt= PaO2ground − 26,6.Results: None of the controls required in-flight oxygen neither by HAST or by the five predictive equations. Eleven CF-patients had PaO2alt < 50 mmHg, accessed by HAST. The positive predictive value was 50% (1st), 87.5% (2nd and 3rd), 77.78% (4th) and 58.33% (5th). Areas under the curve were 78.95% (1st), 84.69% (2nd), 88.04% (3rd) and 78.95% (4th and 5th). FEV1 and PaO2ground were correlated with HAST results.Conclusions: The 3rd equation gave the best predictions in comparison with results obtained by HAST. However, because the individual differences found were substantial for all equations, we still recommend performing a HAST whenever possible to confidently access in-flight hypoxia and the need for oxygen.