title: Effects of hypercapnia on peripheral vascular reactivity in elderly patients with acute exacerbation of chronic obstructive pulmonary disease.
abstract: Blood acid-base imbalance has important effects on vascular reactivity, which can be related to nitric oxide (NO) concentration and increased during hypercapnia. Release of NO seems to be linked to H+ and CO2 concentration and to exacerbation of chronic obstructive pulmonary disease (COPD), a common medical condition in the elderly. Flow-mediated dilation (FMD), a valuable cardiovascular risk indicator, allows assessment of endothelial-dependent vasodilation, which is to a certain extent mediated by NO. We investigated the effects of hypercapnia and acid-base imbalance on endothelial-dependent vasodilation by measurement of FMD in 96 elderly patients with acute exacerbation of COPD. Patients underwent complete arterial blood gas analysis and FMD measurement before (phase 1) and after (phase 2) standard therapy for acute exacerbation of COPD and recovery. Significant differences between phase 1 and phase 2 were observed in the mean values of pH (7.38±0.03 versus 7.40±0.02, P<0.001), pO2 (59.6±4.9 mmHg versus 59.7±3.6 mmHg, P<0.001), pCO2 (59.3±8.63 mmHg versus 46.7±5.82 mmHg, P<0.001), FMD (10.0%±2.8% versus 8.28%±2.01%, P<0.001) and blood flow rate (1.5±0.3 m/s versus 1.5±0.3 m/s, P=0.001). FMD values were positively correlated with pCO2 values (r=0.294, P=0.004) at baseline. A significant correlation was also found between relative changes in FMD and pCO2 levels, passing from phase 1 to phase 2 (r=0.23, P=0.023). Patients with higher baseline endothelium-dependent vasodilation as evaluated by FMD showed greater modification with regard to pCO2 changes (2.6±1.39 versus 1.59±1.4, P=0.012). In conclusion, endothelium-dependent vasodilation as evaluated by FMD was elevated during hypercapnia, and varied significantly according to pCO2 changes in patients with higher baseline levels, suggesting that vascular reactivity in acute COPD exacerbations in the elderly depends on integrity of the vascular endothelium.
authors.affiliation: Division of Internal Medicine and Chronobiology Unit, Foggia, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: de Matthaeis
authors.affiliation: Geriatrics Unit and Gerontology, Geriatrics Research Laboratory, Department of Medical Sciences, Foggia, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Greco
authors.affiliation: Geriatrics Unit and Gerontology, Geriatrics Research Laboratory, Department of Medical Sciences, Foggia, Italy.
authors.forename: Mariangela Pia
authors.initials: MP
authors.lastname: Dagostino
authors.affiliation: Geriatrics Unit and Gerontology, Geriatrics Research Laboratory, Department of Medical Sciences, Foggia, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Paroni
authors.affiliation: Unit of Biostatistics, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Fontana
authors.affiliation: Division of Internal Medicine and Chronobiology Unit, Foggia, Italy ; Euro-Mediterranean Institute of Sciences and Technology, Palermo, Italy ; University College London, Institute for Liver and Digestive Health, Division of Medicine, Royal Free Campus, London, UK.
authors.forename: Manlio
authors.initials: M
authors.lastname: Vinciguerra
authors.affiliation: Division of Internal Medicine and Chronobiology Unit, Foggia, Italy.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Mazzoccoli
authors.affiliation: Geriatrics Unit and Gerontology, Geriatrics Research Laboratory, Department of Medical Sciences, Foggia, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Seripa
authors.affiliation: Geriatrics Unit, University of Foggia, Foggia, Italy.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Vendemiale
mesh_terms: D000137:Acid-Base Imbalance / Q000150:complications / Q000503:physiopathology; D000368:Aged; D000369:Aged, 80 and over; D001775:Blood Circulation / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000150:complications* / Q000503:physiopathology; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology; D014664:Vasodilation / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide
keywords: chronic obstructive pulmonary disease; elderly; flow-mediated dilation; hypercapnia; vascular reactivity