Publications
514 results found
Hopkinson NS, Polkey MI, Curtis K, et al., 2015, Acute dietary nitrate supplementation and exercise performance in COPD: a double-blind, placebo-controlled, randomised controlled pilot study, PLOS One, Vol: 10, ISSN: 1932-6203
BackgroundDietary nitrate supplementation can enhance exercise performance in healthy people, but it is not clear if it is beneficial in COPD. We investigated the hypotheses that acute nitrate dosing would improve exercise performance and reduce the oxygen cost of submaximal exercise in people with COPD.MethodsWe performed a double-blind, placebo-controlled, cross-over single dose study. Subjects were randomised to consume either nitrate-rich beetroot juice (containing 12.9mmoles nitrate) or placebo (nitrate-depleted beetroot juice) 3 hours prior to endurance cycle ergometry, performed at 70% of maximal workload assessed by a prior incremental exercise test. After a minimum washout period of 7 days the protocol was repeated with the crossover beverage.Results21 subjects successfully completed the study (age 68±7years; BMI 25.2±5.5kg/m2; FEV1 percentage predicted 50.1±21.6%; peak VO2 18.0±5.9ml/min/kg). Resting diastolic blood pressure fell significantly with nitrate supplementation compared to placebo (-7±8mmHg nitrate vs. -1±8mmHg placebo; p = 0.008). Median endurance time did not differ significantly; nitrate 5.65 (3.90–10.40) minutes vs. placebo 6.40 (4.01–9.67) minutes (p = 0.50). However, isotime oxygen consumption (VO2) was lower following nitrate supplementation (16.6±6.0ml/min/kg nitrate vs. 17.2±6.0ml/min/kg placebo; p = 0.043), and consequently nitrate supplementation caused a significant lowering of the amplitude of the VO2-percentage isotime curve.ConclusionsAcute administration of oral nitrate did not enhance endurance exercise performance; however the observation that beetroot juice caused reduced oxygen consumption at isotime suggests that further investigation of this treatment approach is warranted, perhaps targeting a more hypoxic phenotype.
Suh E-S, Mandal S, Harding R, et al., 2015, Neural respiratory drive predicts clinical deterioration and safe discharge in exacerbations of COPD, Thorax, Vol: 70, Pages: 1123-1130, ISSN: 0040-6376
Rationale Hospitalised patients with acuteexacerbation of COPD may deteriorate despite treatment,with early readmission being common.Objectives To investigate whether neural respiratorydrive, measured using second intercostal space parasternalmuscle electromyography (EMGpara), would identifyworsening dyspnoea and physician-defined inpatientclinical deterioration, and predict early readmission.Methods Patients admitted to a single-site universityhospital with exacerbation of COPD were enrolled.Spirometry, inspiratory capacity (IC), EMGpara, routinephysiological parameters, modified early warning score(MEWS), modified Borg scale for dyspnoea and physiciandefinedepisodes of deterioration were recorded daily untildischarge. Readmissions at 14 and 28 days post dischargewere recorded.Measurements and main results 120 patients wererecruited (age 70±9 years, forced expiratory volume in 1 s(FEV1) of 30.5±11.2%). Worsening dyspnoea, defined asat least one-point increase in Borg scale, was associatedwith increases in EMGpara%max and MEWS, whereas anincrease in EMGpara%max alone was associated withphysician-defined inpatient clinical deterioration.Admission-to-discharge change (Δ) in the normalised valueof EMGpara (ΔEMGpara%max) was inversely correlated withΔFEV1 (r=−0.38, p<0.001) and ΔIC (r=−0.44, p<0.001).ΔEMGpara%max predicted 14-day readmission (OR 1.13,95% 1.03 to 1.23) in the whole cohort and 28-dayreadmission in patients under 85 years (OR 1.09, 95% CI1.01 to 1.18). Age (OR 1.08, 95% CI 1.03 to 1.14) and12-month admission frequency (OR 1.29, 1.01 to 1.66),also predicted 28-day readmission in the whole cohort.Conclusions Measurement of neural respiratory drive byEMGpara represents a novel physiological biomarker thatmay be helpful in detecting inpatient clinical deteriorationand identifying the risk of early readmission amongpatients with exacerbations of COPD.
Savi D, Simmonds N, Di Paolo M, et al., 2015, Relationship between pulmonary exacerbations and daily physical activity in adults with cystic fibrosis, BMC Pulmonary Medicine, Vol: 15, ISSN: 1471-2466
Background: The aim of this study was to examine the relationship between pulmonary exacerbations andphysical activity (PA) in adults with cystic fibrosis (CF).Methods: We grouped adults with CF according to their exacerbation status in the year before study enrolment:(1) <1 exacerbation/year; (2) 1–2 exacerbations/year; and (3) >2 exacerbations/year. PA was assessed objectively bymeans of an accelerometer at the time of study enrolment.Results: Patients with >2 exacerbations/year spent less time in PA; specifically, fewer activities of mild intensity [>3metabolic equivalents (METs)], and lower active energy expenditure (P = 0.01 and P = 0.03, respectively). Aftercorrecting for relevant confounders, PA levels were not related to the exacerbation frequency in the preceding year.PA at moderate intensity (4.8–7.2 METs) or greater (>7.2 METs) was independently associated with gender and FEV1% predicted (P = 0.007 and P = 0.04, respectively). Compared with men, women had reduced vigorous activities(P = 0.01) and active energy expenditure (P = 0.01).Conclusions: Adult CF patients with more pulmonary exacerbations in the preceding year have more advanceddisease and are less active than their peers. PA was independently associated with gender and airflow obstruction.Gender differences in PA are evident in CF adults
Hopkinson NS, Hart N, Jenkins G, et al., 2015, Embracing social media., Thorax, Vol: 70, ISSN: 0040-6376
Boutou AK, Zoumot Z, Nair A, et al., 2015, The Impact of Homogeneous Versus Heterogeneous Emphysema on Dynamic Hyperinflation in Patients With Severe COPD Assessed for Lung Volume Reduction, COPD: Journal of Chronic Obstructive Pulmonary Disease, Vol: 12, Pages: 598-605, ISSN: 1541-2555
Dynamic hyperinflation (DH) is a pathophysiologic hallmark of Chronic Obstructive Pulmonary Disease (COPD). The aim of this study was to investigate the impact of emphysema distribution on DH during a maximal cardiopulmonary exercise test (CPET) in patients with severe COPD. This was a retrospective analysis of prospectively collected data among severe COPD patients who underwent thoracic high-resolution computed tomography, full lung function measurements and maximal CPET with inspiratory manouvers as assessment for a lung volume reduction procedure. ΔIC was calculated by subtracting the end-exercise inspiratory capacity (eIC) from resting IC (rIC) and expressed as a percentage of rIC (ΔIC %). Emphysema quantification was conducted at 3 predefined levels using the syngo PULMO-CT (Siemens AG); a difference >25% between best and worse slice was defined as heterogeneous emphysema. Fifty patients with heterogeneous (62.7% male; 60.9 ± 7.5 years old; FEV1% = 32.4 ± 11.4) and 14 with homogeneous emphysema (61.5% male; 62.5 ± 5.9 years old; FEV1% = 28.1 ± 10.3) fulfilled the enrolment criteria. The groups were matched for all baseline variables. ΔIC% was significantly higher in homogeneous emphysema (39.8% ± 9.8% vs.31.2% ± 13%, p = 0.031), while no other CPET parameter differed between the groups. Upper lobe predominance of emphysema correlated positively with peak oxygen pulse, peak oxygen uptake and peak respiratory rate, and negatively with ΔIC%. Homogeneous emphysema is associated with more DH during maximum exercise in COPD patients.
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