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IntroductionImpulse oscillometry (IOS) is used to measure airway impedance. It is an effective tool for diagnosing and treating respiratory diseases, and it has the advantage that it does not require forced respiratory maneuvers. IOS reference values are required for each population group.ObjectiveThis study aimed to determine the IOS reference values and bronchodilator response in healthy preschool children living in Bogotá, Colombia.MethodsWe performed a cross-sectional study in preschool children who had no history of respiratory disease; 96 children fit the parameters for testing to determine normal values according to the American Thoracic Society and European Respiratory Society criteria.ResultsValues for respiratory resistance (Rrs) and reactance (Xrs) at 5, 10, and 20 Hz, respiratory impedance (Zrs, and resonance frequency (Fres) were established. Height was the most influential independent variable for IOS values; an increase in height led to a reduction in Rrs5 and Rrs20 and an increase in Xrs5. After the administration of 400 mcg of salbutamol the values for Rrs5(−17.48%), Rrs20(−8.63%), Fres (−10.68%), and area of reactance (−35.44%) were reduced, meanwhile Xrs5 (15.35%) was increased.ConclusionsNormal IOS values before and after the administration of 400 mcg of salbutamol were determined for a population of children aged 3–5 years at 2,640 m. Reference IOS equations for these children are presented. A relative change of up to −28% and 36% after the use of salbutamol for respiratory resistance and reactance, respectively, should be considered as an upper limit of the normal range, and possible appropriate cut-off values for defining significant response for evaluating therapeutic interventions.

Background: Pulmonary hypertension (PH) is associated with decreased exercise tolerance in chronic obstructive pulmonary disease (COPD) patients, but in the altitude the response to exercise in those patients is unknown. Our objective was to compare exercise capacity, gas exchange and ventilatory alterations between COPD patients with PH (COPD-PH) and without PH (COPD-nonPH) residents at high altitude (2640 m). Methods: One hundred thirty-two COPD-nonPH, 82 COPD-PH, and 47 controls were included. Dyspnea by Borg scale, oxygen consumption (VO2), work rate (WR), ventilatory equivalents (VE/VCO2), dead space to tidal volume ratio (VD/VT), alveolar-arterial oxygen tension gradient (AaPO2), and arterial-end-tidal carbon dioxide pressure gradient (Pa-ETCO2) were measurement during a cardiopulmonary exercise test. For comparison of variables between groups, Kruskal-Wallis or one-way ANOVA tests were used, and stepwise regression analysis to test the association between PH and exercise capacity. Results: All COPD patients had a lower exercise capacity and higher PaCO2, A-aPO2 and VD/VT than controls. The VO2 % predicted (61.3 ± 20.6 vs 75.3 ± 17.9; p < 0.001) and WR % predicted (65.3 ± 17.9 vs 75.3 ± 17.9; p < 0.001) were lower in COPD-PH than in COPD-nonPH. At peak exercise, dyspnea was higher in COPD-PH ( p = 0.011). During exercise, in COPD-PH, the PaO2 was lower ( p < 0.001), and AaPO2 ( p < 0.001), Pa-ETCO2 ( p = 0.033), VE/VCO2 ( p = 0.019), and VD/VT ( p = 0.007) were higher than in COPD-nonPH. In the multivariate analysis, PH was significantly associated with lower peak VO2 and WR ( p < 0.001). Conclusion: In COPD patients residing at high altitude, the presence of PH was an independent factor related to the exercise capacity. Also, in COPD-PH patients there were more dyspnea and alterations in gas exchange during the exercise than in those without PH.

Objective:The goal of this study was to compare the microbiology of severe exacerbations of chronic obstructive pulmonary disease (COPD) requiring admission to the intensive care unit (ICU), in patients with pneumonia compared to those that did not have. Methods: We conducted a retrospective cross-sectional study that included patients with severe COPD exacerbation. We took microbiologic and serologic samples to study the etiology of the exacerbation and chest X-ray to see whether or not it had associated pneumonia. Results: Ninety-one patients were included in the study. 53/91 (58%) had pneumonia. The most prevalent bacteria isolated were H. influenzae (25.3%), Moraxella spp (22%), H. parainfluenza (14.3%), Serratia marcescens (13.2%), mixed flora (9.9%) and methicillin-susceptible Staphylococcus aureus (9.9%). A statistically significant difference could not be demonstrated between the two groups. We detected 24.2% of bacterial resistance in both groups, the most frequent being AMPc (13 cases). Discussion: Bacterial pneumonia in COPD patients is higher in comparison with patients with acute exacerbation. Even though we did not find a significant difference in the microbiology of the groups with or without pneumonia, there are variables such as past smoking related to having pneumonia. Patients with pneumonia also had higher severity scores.