The Coupling of Peripheral Blood Pressure and Ventilatory Responses during Exercise in Young Adults with Cystic FibrosisReportar como inadecuado




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Purpose

Cystic fibrosis CF is commonly recognized as a pulmonary disease associated with reduced airway function. Another primary symptom of CF is low exercise capacity where ventilation and gas-exchange are exacerbated. However, an independent link between pathophysiology of the pulmonary system and abnormal ventilatory and gas-exchange responses during cardiopulmonary exercise testing CPET has not been established in CF. Complicating this understanding, accumulating evidence suggests CF demonstrate abnormal peripheral vascular function; although, the clinical implications are unclear. We hypothesized that compared to controls, relative to total work performed WorkTOT, CF would demonstrate increased ventilation accompanied by augmented systolic blood pressure SBP during CPET.

Methods

16 CF and 23 controls age: 23±4 vs. 27±4 years, P = 0.11; FEV1%predicted: 73±14 vs. 96±5, P<0.01 participated in CPET. Breath-by-breath oxygen uptake , ventilation , and carbon dioxide output were measured continuously during incremental 3-min stage step-wise cycle ergometry CPET. SBP was measured via manual sphygmomanometry. Linear regression was used to calculate slope from rest to peak-exercise.

Results

Compared to controls, CF performed less WorkTOT during CPET 90±19 vs. 43±14 kJ, respectively, P<0.01. With WorkTOT as a covariate, peak 62±8 vs. 90±4 L-min, P = 0.76, 1.8±0.3 vs. 2.7±0.1 L-min, P = 0.40, and SBP 144±13 vs. 152±6 mmHg, P = 0.88 were similar between CF and controls, respectively; whereas CF demonstrated increased slope 38±4 vs. 28±2, P = 0.02 but lower peak versus controls 22±5 vs. 33±4 mL-kg-min, P<0.01. There were modest-to-moderate correlations between peak SBP with r = 0.30, r = 0.70, and r = 0.62 in CF.

Conclusions

These data suggest that relative to WorkTOT, young adults with mild-to-moderate severity CF demonstrate augmented slope accompanied by increased SBP during CPET. Although the underlying mechanisms remain unclear, the coupling of ventilatory inefficiency with increased blood pressure suggest important contributions from peripheral pathophysiology to low exercise capacity in CF.



Autor: Erik H. Van Iterson , Courtney M. Wheatley, Sarah E. Baker, Thomas P. Olson, Wayne J. Morgan, Eric M. Snyder

Fuente: http://plos.srce.hr/



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