Read by QxMD icon Read

Exercise induced dyspnea with normal oxygen levels

Rainer Gloeckl, Sebastian Teschler, Inga Jarosch, Jeffrey W Christle, Wolfgang Hitzl, Klaus Kenn
The two-minute walk test (2MWT) is less well validated than the well-known six-minute walk test (6MWT) as a field walking test in patients with chronic obstructive pulmonary disease (COPD). The primary objective of this study was to compare the accuracy of the 2MWT to the 6MWT in detecting exercise-induced oxygen desaturation in patients with severe COPD. Twenty-six patients with COPD (age: 61 ± 10 years, forced expired volume in one second: 37 ± 10%) that were normoxemic at rest performed a 2MWT and a 6MWT under normal ambient conditions on two consecutive days in random order...
March 8, 2016: Chronic Respiratory Disease
Robert Naeije, Rebecca Vanderpool, Bishnu P Dhakal, Rajeev Saggar, Rajan Saggar, Jean-Luc Vachiery, Gregory D Lewis
Exercise stresses the pulmonary circulation through increases in cardiac output (.Q) and left atrial pressure. Invasive as well as noninvasive studies in healthy volunteers show that the slope of mean pulmonary artery pressure (mPAP)-flow relationships ranges from 0.5 to 3 mm Hg.min.L(-1). The upper limit of normal mPAP at exercise thus approximates 30 mm Hg at a .Q of less than 10 L.min(-1) or a total pulmonary vascular resistance at exercise of less than 3 Wood units. Left atrial pressure increases at exercise with an average upstream transmission to PAP in a close to one-for-one mm Hg fashion...
March 15, 2013: American Journal of Respiratory and Critical Care Medicine
Nikunj R Shah, M Bilal Iqbal, Andrew Barlow, John Bayliss
We report the case of a 27-year-old male athlete presenting with severe dyspnoea 24 hours after completing an "Ironman Triathlon." Subsequent chest radiology excluded pulmonary embolus but confirmed an acute lung injury (ALI). Echocardiography corroborated a normal brain natriuretic peptide level by demonstrating good biventricular systolic function with no regional wall motion abnormalities. He recovered well, without requiring ventilatory support, on supplemental oxygen therapy and empirical antibiotics. To date, ALI following severe physical exertion has never been described...
November 2011: Clinical Journal of Sport Medicine
Gordon L Snider
This essay summarizes 16 reports, published since 1956, that describe the effects of hyperoxia on exercise endurance in persons with COPD who have severe airflow obstruction (ie, FEV(1) < 1.0 L or < 39% of predicted) and mild hypoxemia at rest (ie, PaO(2) > 62 mm Hg or arterial oxygen saturation [SaO(2)] measured by pulse oximetry of > 91%). The term hyperoxia is used because, in a proportion of study participants, oxygen administration increased exercise endurance in a dose-dependent fashion, up to a fraction of inspired oxygen of 0...
November 2002: Chest
M A Babcock, B D Johnson, D F Pegelow, O E Suman, D Griffin, J A Dempsey
We examined the effects of hypoxia on exercise-induced diaphragmatic fatigue. Eleven subjects with a mean maximal O2 uptake of 52.4 +/- 0.7 completed one normoxic (arterial O2 saturation 96-94%) and one hypoxic (inspiratory O2 fraction = 0.15; arterial O2 saturation 83-77%) exercise test at 85% maximal O2 uptake to exhaustion on separate days. Supramaximal bilateral phrenic nerve stimulation (BPNS) was used to determine the pressure generation of the diaphragm pre- and postexercise at 1, 10, and 20 Hz...
January 1995: Journal of Applied Physiology
R G Haller, S F Lewis, R W Estabrook, S DiMauro, S Servidei, D W Foster
A 27-yr-old woman with lifelong severe exercise intolerance manifested by muscle fatigue, lactic acidosis, and prominent symptoms of dyspnea and tachycardia induced by trivial exercise was found to have a skeletal muscle respiratory chain defect characterized by low levels of reducible cytochromes a + a3 and b in muscle mitochondria and marked deficiency of cytochrome c oxidase (complex IV) as assessed biochemically and immunologically. Investigation of the pathophysiology of the exercise response in the patient revealed low maximal oxygen uptake (1/3 that of normal sedentary women) in cycle exercise and impaired muscle oxygen extraction as indicated by profoundly low maximal systemic arteriovenous oxygen difference (5...
July 1989: Journal of Clinical Investigation
P M Simon, R M Schwartzstein, J W Weiss, K Lahive, V Fencl, M Teghtsoonian, S E Weinberger
Various theories about the genesis of dyspnea have often assumed that the sensation is similar from patient to patient and is generated by a single underlying mechanism. To investigate whether breathlessness induced in normal volunteers by different stimuli represents one or more than one sensation, we studied 30 subjects in whom breathlessness was induced by each of 8 different stimuli: breath-holding, CO2 inhalation, inhalation of CO2, with ventilation voluntarily targeted below the level dictated by chemical drive, breathing with a resistive load, breathing with an elastic load, voluntary elevation of functional residual capacity, voluntary limitation of tidal volume, and exercise...
October 1989: American Review of Respiratory Disease
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"