Arterial blood gases and ventilation at rest by age and sex in an adult Andean population resident at high altitude

González-García, Mauricio; Maldonado, Darío; Barrero, Margarita; Casas, Alejandro; Padilla, Rogelio Pérez; Torres-Duque, Carlos A.

doi:10.1007/s00421-020-04498-z

Cited by 25 publications

(26 citation statements)

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“…The increase in ventilation with the decrease of the arterial carbon dioxide pressure (PaCO 2 ) is the main compensating mechanism that attenuates the drop in the PaO 2 (West, 2004). In Bogotá, a city located at high altitude (2,640 m, BP 560 mm Hg), the PaCO 2 at rest in healthy subjects decreases to approximately 33 mm Hg, and the PaO 2 is 65 mm Hg, with values less than 60 mm Hg in the elderly (Gonzalez-Garcia et al, 2020) and even lower values in COPD patients (Gonzalez-Garcia et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Exercise Capacity, Ventilatory Response, and Gas Exchange in COPD Patients With Mild to Severe Obstruction Residing at High Altitude

2021

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BackgroundExercise intolerance, desaturation, and dyspnea are common features in patients with chronic obstructive pulmonary disease (COPD). At altitude, the barometric pressure (BP) decreases, and therefore the inspired oxygen pressure and the partial pressure of arterial oxygen (PaO2) also decrease in healthy subjects and even more in patients with COPD. Most of the studies evaluating ventilation and arterial blood gas (ABG) during exercise in COPD patients have been conducted at sea level and in small populations of people ascending to high altitudes. Our objective was to compare exercise capacity, gas exchange, ventilatory alterations, and symptoms in COPD patients at the altitude of Bogotá (2,640 m), of all degrees of severity.MethodsMeasurement during a cardiopulmonary exercise test of oxygen consumption (VO2), minute ventilation (VE), tidal volume (VT), heart rate (HR), ventilatory equivalents of CO2 (VE/VCO2), inspiratory capacity (IC), end-tidal carbon dioxide tension (PETCO2), and ABG. For the comparison of the variables between the control subjects and the patients according to the GOLD stages, the non-parametric Kruskal–Wallis test or the one-way analysis of variance test was used.ResultsEighty-one controls and 525 patients with COPD aged 67.5 ± 9.1 years were included. Compared with controls, COPD patients had lower VO2 and VE (p < 0.001) and higher VE/VCO2 (p = 0.001), A-aPO2, and VD/VT (p < 0.001). In COPD patients, PaO2 and saturation decreased, and delta IC (p = 0.004) and VT/IC increased (p = 0.002). These alterations were also seen in mild COPD and progressed with increasing severity of the obstruction.ConclusionThe main findings of this study in COPD patients residing at high altitude were a progressive decrease in exercise capacity, increased dyspnea, dynamic hyperinflation, restrictive mechanical constraints, and gas exchange abnormalities during exercise, across GOLD stages 1–4. In patients with mild COPD, there were also lower exercise capacity and gas exchange alterations, with significant differences from controls. Compared with studies at sea level, because of the lower inspired oxygen pressure and the compensatory increase in ventilation, hypoxemia at rest and during exercise was more severe; PaCO2 and PETCO2 were lower; and VE/VO2 was higher.

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Section: Introductionmentioning

confidence: 99%

Exercise Capacity, Ventilatory Response, and Gas Exchange in COPD Patients With Mild to Severe Obstruction Residing at High Altitude

2021

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“…As expected, there were differences in arterial blood gases between cities of different altitude. In patients from Bogotá and Mexico City, PaCO 2 was lower, explained by the adaptive mechanism of hyperventilation at altitude ( 10 , 29 ). Due to the decrease in PAO 2 , PaO 2 and saturation at rest and during exercise were significantly lower in patients from higher altitude cities.…”

Section: Discussionmentioning

confidence: 95%

“…We highlight the higher percentage of subjects with PH in the TE in the cities of higher altitude (51.7 vs. 15.3%, p < 0.001). The mechanism of hypoxic vasoconstriction with a secondary increase in pulmonary vascular resistance triggered by lower PAO 2 values at altitude, the pulmonary artery remodeling described in long-term exposure to hypoxia and the erythrocytosis described in altitude in healthy subjects and in patients with respiratory disease (10,26), could explain the development of PH in these patients (14,15). Along the same lines of our data, in previous studies in Mexico City and Bogotá, high prevalence of PH have been described in patients with chronic respiratory disease (27,28).…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, in cities located at high altitude such as Mexico City (2,240 m) and Bogotá (2,640 m), due to the decrease in barometric pressure (PB) and inspired oxygen pressure, the alveolar (PAO 2 ) and arterial oxygen pressure (PaO 2 ) are lower compared to sea level. This PaO 2 decreases even more with age (9,10) and in subjects with lung disease (6,(11)(12)(13). Although the decreased PAO 2 causes hypoxic pulmonary vasoconstriction, which can increase pulmonary artery pressure at less advanced stages of respiratory disease (14,15), there are no studies reporting more PH in patients with IPF living at high altitude.…”

Section: Introductionmentioning

confidence: 99%

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Comorbidities of Patients With Idiopathic Pulmonary Fibrosis in Four Latin American Countries. Are There Differences by Country and Altitude?

et al. 2021

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Background: Comorbidities in idiopathic pulmonary fibrosis (IPF) affect quality of life, symptoms, disease progression and survival. It is unknown what are the comorbidities in patients with IPF in Latin America (LA) and if there are differences between countries. Our objective was to compare IPF comorbidities in four countries and analyze possible differences by altitude.Methods: Patients with IPF according 2012 ATS/ERS/JRS/ALAT guidelines, from two cities with an altitude of ≥2,250 m: Mexico City (Mexico) and Bogotá (Colombia) and from three at sea level: Buenos Aires (Argentina) and Lima and Trujillo (Peru). Comorbidities and pulmonary function tests were taken from clinical records. Possible pulmonary hypertension (PH) was defined by findings in the transthoracic echocardiogram of systolic pulmonary arterial pressure (sPAP) >36 mmHg or indirect signs of PH in the absence of other causes of PH. Emphysema as the concomitant finding of IPF criteria on chest tomography plus emphysema in the upper lobes. ANOVA or Kruskal Wallis and χ2-tests were used for comparison.Results: Two hundred and seventy-six patients were included, 50 from Argentina, 86 from Colombia, 91 from Mexico and 49 from Peru. There prevalence of PH was higher in Colombia and Mexico (p < 0.001), systemic arterial hypertension in Argentina (p < 0.015), gastro-esophageal reflux and dyslipidemia in Colombia and Argentina (p < 0.001) and diabetes mellitus in Mexico (p < 0.007). Other comorbidities were obesity (28.4%), coronary artery disease (15.2%) and emphysema (14.9%), with no differences between countries. There was more PH in the altitude cities than those at sea level (51.7 vs. 15.3%, p < 0.001). In patients from Bogotá and Mexico City, arterial oxygen pressure, saturation (p < 0.001) and carbon monoxide diffusing capacity (p = 0.004) were significantly lower than in cities at sea level.Conclusions: In this study with a significant number of patients, we were able to describe and compare the comorbidities of IPF in four LA countries, which contributes to the epidemiological data of this disease in the region. The main results were the differences in comorbidities between the countries and more PH in the subjects residing in the cities of higher altitude, a finding that should be validated in future studies.

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“…PaO 2 values fall with age (between 0.25 and 0.3 Torr or mmHg per year) and with increasing weight, among other factors 23 . PaCO 2 remains more constant throughout life, although an increase in PaCO 2 with age, especially in postmenopausal women, has been described 24 .…”

Section: Acclimatization To Altitudementioning

confidence: 99%

Adaptation to Moderate Altitude Hypoxemia: The Example of the Valley of Mexico

Pérez-Padilla¹

2022

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A large world population resides at moderate altitude. In the Valley of Mexico (2,240 m above sea level), its inhabitants, breathe approximately 29% more on average and have 10% increased hemoglobin concentrations compared to sea level residents, among other differences. These compensations reduce but not eliminate the impact of altitude hypoxemia. The objective of the manuscript is to review and describe the information available on health and disease at moderate altitudes, mainly with data in Spanish language from Latin-American countries. Young adults in Mexico City have an SaO 2 between 92% and 94% versus 97% at sea level, frequently decreasing below 90% during sleep and intense exercise. It is likely that among the population living at this altitude, lung growth, and development during pregnancy and infancy are enhanced, and that after residing for several tens of thousands of years, more important adaptations in oxygen transport and utilization have developed, but we are not certain about it. For patients with respiratory diseases, residing at moderate altitudes implies increased hypoxemia and clinical deterioration, unless supplementary oxygen is prescribed or patients move to sea level. Hyperventilation increases exposure of residents to air pollutants compared to those living in cities with similar concentrations of pollutants, although at sea level. Humans evolved at sea level and lack the best-known adaptations to reside at moderate or high altitudes.Residents of moderate altitudes breathe deeply the city´s air with all its pollutants, and more often require supplementary oxygen. (REV INVEST CLIN. 2022;74(1):4-15

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Arterial blood gases and ventilation at rest by age and sex in an adult Andean population resident at high altitude

Cited by 25 publications

References 35 publications

Exercise Capacity, Ventilatory Response, and Gas Exchange in COPD Patients With Mild to Severe Obstruction Residing at High Altitude

Exercise Capacity, Ventilatory Response, and Gas Exchange in COPD Patients With Mild to Severe Obstruction Residing at High Altitude

Comorbidities of Patients With Idiopathic Pulmonary Fibrosis in Four Latin American Countries. Are There Differences by Country and Altitude?

Adaptation to Moderate Altitude Hypoxemia: The Example of the Valley of Mexico

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