Effects of hypercapnia on peripheral vascular reactivity in elderly patients with acute exacerbation of chronic obstructive pulmonary disease

Angela de Matthaeis,1 Antonio Greco,2,* Mariangela Pia Dagostino,2 Giulia Paroni,2 Andrea Fontana,3 Manlio Vinciguerra,1,4,5 Gianluigi Mazzoccoli,1,* Davide Seripa,2 Gianluigi Vendemiale61Division of Internal Medicine and Chronobiology Unit, 2Geriatrics Unit and Gerontology, Geriatrics Research Laboratory, Department of Medical Sciences, 3Unit of Biostatistics, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, 4Euro-Mediterranean Institute of Sciences and Technology, Palermo, Italy; 5University College London, Institute for Liver and Digestive Health, Division of Medicine, Royal Free Campus, London, UK; 6Geriatrics Unit, University of Foggia, Foggia, Italy*These authors contributed equally to this workAbstract: 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