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Respiratory exchange ratio in performance

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https://www.readbyqxmd.com/read/28624095/fontan-circulation-over-time
#1
Djoeke Wolff, Joost P van Melle, Beatrijs Bartelds, Floris-Jan S Ridderbos, Graziella Eshuis, Elisabeth B H J van Stratum, Salvador J Recinos, Brigitte W M Willemse, Hans Hillege, Tineke P Willems, Tjark Ebels, Rolf M F Berger
The unique, unphysiological Fontan circulation is associated with an impaired functional status of the patients that is suggested to deteriorate over time. Unfortunately, previous studies did not integrate both pulmonary and cardiac determinants of functional status. In addition, a comparison with the natural decrease in exercise capacity in healthy subjects (in both children and adults) is lacking. This single-center study aims to investigate the functional status in a cohort of Fontan patients in relation to time since Fontan completion and to identify its determinants, including cardiac characteristics and pulmonary characteristics...
May 11, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/28578113/safety-of-percutaneous-dilatational-tracheostomy-in-patients-with-acute-brain-injury-and-a-reduced-pao2-fio2-ratio-a-retrospective-analysis-of-54-patients
#2
Claudia Ditz, Jann F Wojak, Emma Smith, Abdulkareem Abusamha, Volker M Tronnier, Jan Gliemroth, Jan N Kuechler
OBJECTIVE: Percutaneous Dilatational Tracheostomy (PDT) is a commonly performed method in neurocritical care, whose safety has been proven in numerous studies. Nevertheless, there are poor data regarding the application in patients with acute brain injury and poor respiratory function. The purpose of this study was to evaluate the incidence of hypoxemia and hypercapnia during PDT in those patients. METHODS: In a retrospective analysis, we acquired data from 54 patients with an acute brain injury (ABI) and a reduced PaO2/FiO2 ratio (PaO2/FiO2<300mmHg)...
May 31, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28515830/how-different-respiratory-rate-patterns-affect-cardiorespiratory-variables-and-performance
#3
Minas Nalbandian, Zsolt Radak, Jun Taniguchi, Takeda Masaki
This study aims to elucidate how respiratory rate (RR) patterns may affect respiratory gas exchange variables and performance during incremental intensity- exercise. 10 healthy young men (mean ± SD, age: 20.7 ± 0.5 years, height: 174.3 ± 5.7 cm, and body mass: 72.6 ± 10.4 kg) performed three incremental tests on a cycle ergometer at three different RR (60, 45 and 30 breaths per min) in each trial. During the tests, tidal volume (TV), minute ventilation (VE), fractional content of oxygen (FeO2), fractional content of carbon dioxide (FeCO2), oxygen uptake (VO2), expiratory carbon dioxide (VCO2), equivalent of oxygen (EqO2), VE/VCO2, and respiratory exchange ratio (RER) were determinate breath-by-breath...
2017: International Journal of Exercise Science
https://www.readbyqxmd.com/read/28510504/cardiopulmonary-exercise-testing-basics-of-methodology-and-measurements
#4
Alessandro Mezzani
Cardiopulmonary exercise testing adds measurement of ventilation and volume of oxygen uptake and exhaled carbon dioxide to routine physiological and performance parameters obtainable from conventional exercise testing, furnishing an all-round vision of the systems involved in both oxygen transport from air to mitochondria and its utilization during exercise. Peculiarities of cardiopulmonary exercise testing methodology are the use of ramp protocols and calibration procedures for flow meters and gas analyzers...
May 16, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28468260/6mwt-performance-and-its-correlations-with-vo%C3%A2-and-handgrip-strength-in-home-dwelling-mid-aged-and-older-chinese
#5
Qing Zhang, Hailin Lu, Shiqin Pan, Yuan Lin, Kun Zhou, Li Wang
Six-minute walk test (6MWT) performance is more commonly used in clinic patients with chronic cardiopulmonary diseases but not in home-dwelling individuals of similar age, and its correlations with oxygen uptake (VO₂) and muscle strength require further investigation. The current study determined the 6MWT performance of 106 home-dwelling residents (mean age of 62 years) in Suzhou, China. VO₂ at a respiratory exchange ratio (R) of 1 was measured through graded cycling exercise tests on 46 participants. Handgrip strength of all participants was tested...
April 29, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/28466818/evaluation-of-relationship-between-aerobic-fitness-level-and-range-of-isocapnic-buffering-periods-during-incremental-exercise-test
#6
S Algul, O Ozcelik, B Yilmaz
The purpose of this study is to examine the relationship between the amount of O2 uptake (VO2) in the range of isocapnic buffering (ICB) periods and aerobic fitness levels of subjects with different exercise tolerance levels. A total of 50 young male subjects (20.8±0.4 years) performed an incremental exercise test using a cycle ergometer to determinetheir anaerobic threshold (AT), respiratory compensation point (RCP) and maximal exercise capacity (Wmax). The ICB period is defined as the region between AT and RCP...
March 31, 2017: Cellular and Molecular Biology
https://www.readbyqxmd.com/read/28442632/effect-of-aerobic-exercise-training-on-ventilatory-efficiency-and-respiratory-drive-in-obese-subjects
#7
Mehdi Chlif, Anis Chaouachi, Said Ahmaidi
BACKGROUND: Obese patients show a decline in exercise capacity and diverse degrees of dyspnea in association with mechanical abnormalities, increased ventilatory requirements secondary to the increased metabolic load, and a greater work of breathing. Consequently, obese patients may be particularly predisposed to the development of respiratory muscle fatigue during exercise. The aim of this study was to assess inspiratory muscle performance during incremental exercise in 19 obese male subjects (body mass index 41 ± 6 kg/m(2)) after aerobic exercise training using the noninvasive, inspiratory muscle tension-time index (TT0...
April 25, 2017: Respiratory Care
https://www.readbyqxmd.com/read/28408022/left-ventricular-assist-device-as-a-bridge%C3%A2-to-recovery-for-patients-with-advanced-heart-failure
#8
Djordje G Jakovljevic, Magdi H Yacoub, Stephan Schueler, Guy A MacGowan, Lazar Velicki, Petar M Seferovic, Sandeep Hothi, Bing-Hsiean Tzeng, David A Brodie, Emma Birks, Lip-Bun Tan
BACKGROUND: Left ventricular assist devices (LVADs) have been used as an effective therapeutic option in patients with advanced heart failure, either as a bridge to transplantation, as destination therapy, or in some patients, as a bridge to recovery. OBJECTIVES: This study evaluated whether patients undergoing an LVAD bridge-to-recovery protocol can achieve cardiac and physical functional capacities equivalent to those of healthy controls. METHODS: Fifty-eight male patients-18 implanted with a continuous-flow LVAD, 16 patients with LVAD explanted (recovered patients), and 24 heart transplant candidates (HTx)-and 97 healthy controls performed a maximal graded cardiopulmonary exercise test with continuous measurements of respiratory gas exchange and noninvasive (rebreathing) hemodynamic data...
April 18, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28382972/bio-inspired-murray-materials-for-mass-transfer-and-activity
#9
Xianfeng Zheng, Guofang Shen, Chao Wang, Yu Li, Darren Dunphy, Tawfique Hasan, C Jeffrey Brinker, Bao-Lian Su
Both plants and animals possess analogous tissues containing hierarchical networks of pores, with pore size ratios that have evolved to maximize mass transport and rates of reactions. The underlying physical principles of this optimized hierarchical design are embodied in Murray's law. However, we are yet to realize the benefit of mimicking nature's Murray networks in synthetic materials due to the challenges in fabricating vascularized structures. Here we emulate optimum natural systems following Murray's law using a bottom-up approach...
April 6, 2017: Nature Communications
https://www.readbyqxmd.com/read/28356130/parecoxib-reduced-ventilation-induced-lung-injury-in-acute-respiratory-distress-syndrome
#10
Fan-You Meng, Wei Gao, Ying-Nan Ju
BACKGROUND: Cyclooxygenase-2 (COX-2) contributes to ventilation induced lung injury (VILI) and acute respiratory distress syndrome (ARDS). The objective of present study was to observe the therapeutic effect of parecoxib on VILI in ARDS. METHODS: In this parallel controlled study performed at Harbin Medical University, China between January 2016 and March 2016, 24 rats were randomly allocated into sham group (S), volume ventilation group/ARDS (VA), parecoxib/volume ventilation group/ARDS (PVA)...
March 29, 2017: BMC Pharmacology & Toxicology
https://www.readbyqxmd.com/read/28346316/impact-of-direction-of-unloading-influence-on-template-rate-of-perceived-exertion
#11
Beau Kjerulf Greer, Patrick R Young, Brooke Thompson, Brendan J Rickert, Matthew F Moran
It is suggested that exercisers engage in a process of teleoanticipation and create an exercise template based upon previous experience with the exercise task which guides their perceptions of the amount of effort required for task completion. The present study examined how altering workload intensity during a positive-pressure treadmill task may impact ratings of perceived exertion (RPE). In a counter-balanced design, 15 collegiate cross country runners (7 males, 8 females) performed two 25-min runs at a constant velocity while bodyweight (BW) was either increased from 60% to 100% (INC) or decreased from 100% to 60% (DEC) in 5 min increments...
March 23, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28340236/diet-density-during-the-first-week-of-life-effects-on-energy-and-nitrogen-balance-characteristics-of-broiler-chickens
#12
D M Lamot, D Sapkota, P J A Wijtten, I van den Anker, M J W Heetkamp, B Kemp, H van den Brand
This study aimed to determine effects of diet density on growth performance, energy balance, and nitrogen balance characteristics of broiler chickens during the first wk of life. Effects of diet density were studied using a dose-response design consisting of 5 dietary fat levels (3.5, 7.0, 10.5, 14.0, and 17.5%). The relative difference in dietary energy level was used to increase amino acid levels, mineral levels, and the premix inclusion level at the same ratio. Chickens were housed in open-circuit climate respiration chambers from d 0 to 7 after hatch...
March 11, 2017: Poultry Science
https://www.readbyqxmd.com/read/28255088/oral-n-acetylcysteine-and-exercise-tolerance-in-mild-chronic-obstructive-pulmonary-disease
#13
Daniel M Hirai, Joshua H Jones, Joel T Zelt, Marianne L da Silva, Robert F Bentley, Brittany Ann Edgett, Brendon James Gurd, Michael E Tschakovsky, Denis E O'Donnell, J Alberto Neder
Heightened oxidative stress is implicated in the progressive impairment of skeletal muscle vascular and mitochondrial function in chronic obstructive pulmonary disease (COPD). Whether accumulation of reactive oxygen species contribute to exercise intolerance in the early stages of COPD is unknown. We examined the effects of oral antioxidant treatment with N-acetylcysteine (NAC) on respiratory, cardiovascular and locomotor muscle function and exercise tolerance in patients with mild COPD. Thirteen patients with forced expiratory volume in one second and forced vital capacity ratio (FEV1/FVC) < lower limit of normal (LLN) and FEV1 ≥ LLN were enrolled in a double-blind, randomized crossover study to receive NAC (1800 mg/day) or placebo for 4 days...
March 2, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28229577/maximal-aerobic-capacity-can-be-increased-by-enhancing-performers-expectancies
#14
Jeff Montes, Gabriele Wulf, James W Navalta
BACKGROUND: Maximum aerobic capacity (VO2max) is widely accepted as the best measure of cardiovascular fitness and aerobic power. The present study investigated whether enhancing participants' performance expectancies through positive social-comparative feedback would increase VO2max. METHODS: Participants were experienced runners who regularly ran for exercise or competitively. All participants completed two VO2max tests within a 2-week period at similar times of the day...
February 22, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28203337/comparison-of-the-efficacy-of-three-natural-surfactants-curosurf-survanta-and-alveofact-in-the-treatment-of-respiratory-distress-syndrome-among-neonates-a-randomized-controlled-trial
#15
Mirhadi Mussavi, Keyvan Mirnia, Khairollah Asadollahi
BACKGROUND: Although several different types of natural surfactants are available, including Alveofact, Curosurf, and Survanta, the preferred type and the magnitude of their effects are unknown. OBJECTIVES: This study was designed to compare the effects of these three surfactants on the gas exchange and clinical outcomes of neonates with respiratory distress syndrome (RDS). METHODS: This triple-blind randomized clinical trial studied all preterm neonates ≤ 37 weeks with RDS who were admitted to the neonatal intensive care unit (NICU) of Taleghani hospital (Tabriz, Iran) between 2012 and 2013...
October 2016: Iranian Journal of Pediatrics
https://www.readbyqxmd.com/read/28153947/corp-measurement-of-the-maximum-oxygen-uptake-vo2max-vo2peak-is-no-longer-acceptable
#16
David C Poole, Andrew M Jones
The maximum rate of VO2 uptake (i.e., VO2max), as measured during large muscle mass exercise such as cycling or running, is widely considered to be the gold standard measurement of integrated cardiopulmonary-muscle oxidative function. The development of rapid-response gas analyzers, enabling measurement of breath-by-breath pulmonary gas exchange, has led to replacement of the discontinuous progressive maximal exercise test (that produced an unambiguous VO2-work rate plateau definitive for VO2max) with the rapidly-incremented or ramp testing protocol...
February 2, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28119843/influence-of-low-peak-respiratory-exchange-ratio-on-cardiac-rehabilitation-in-patients-with-coronary-artery-disease
#17
Chul Kim, Hee Eun Choi, Ki Hoon Lee, Young Joo Kim, Sang Jae Lee
OBJECTIVE: To compare and analyze the effects of cardiac rehabilitation (CR) in two groups based on the peak respiratory exchange ratio (RERpeak) 1.1 values using the exercise tolerance test (ETT) results, and to investigate the reasons for early termination of ETT. METHODS: Patients with acute coronary syndrome who participated in CR exercise training were selected and all subjects underwent 6 weeks of CR exercise training. ETT was performed on a treadmill using a Modified Bruce Protocol before and after CR exercise training...
December 2016: Annals of Rehabilitation Medicine
https://www.readbyqxmd.com/read/28090142/the-midpoint-between-ventilatory-thresholds-approaches-maximal-lactate-steady-state-intensity-in-amateur-cyclists
#18
A B Peinado, Dm Pessôa Filho, V Díaz, P J Benito, M Álvarez-Sánchez, A G Zapico, F J Calderón
The aim was to determine whether the midpoint between ventilatory thresholds (MPVT) corresponds to maximal lactate steady state (MLSS). Twelve amateur cyclists (21.0 ± 2.6 years old; 72.2 ± 9.0 kg; 179.8 ± 7.5 cm) performed an incremental test (25 W·min(-1)) until exhaustion and several constant load tests of 30 minutes to determine MLSS, on different occasions. Using MLSS determination as the reference method, the agreement with five other parameters (MPVT; first and second ventilatory thresholds: VT1 and VT2; respiratory exchange ratio equal to 1: RER = 1...
December 2016: Biology of Sport
https://www.readbyqxmd.com/read/28075500/very-short-short-term-benefit-of-inpatient-outpatient-cardiac-rehabilitation-programs-after-coronary-artery-bypass-grafting-surgery
#19
Dejan Spiroski, Mojsije Andjić, Olivera Ilić Stojanović, Milica Lazović, Ana Djordjević Dikić, Miodrag Ostojić, Branko Beleslin, Snežana Kostić, Marija Zdravković, Dragan Lović
BACKGROUND: Exercise-based rehabilitation is an important part of treatment patients following coronary artery bypass graft (CABG) surgery. HYPOTHESIS: To evaluate effect of very short/short-term exercise training on cardiopulmonary exercise testing (CPET) parameters. METHODS: We studied 54 consecutive patients with myocardial infarction (MI) treated with CABG surgery referred for rehabilitation. The study population consisted of 50 men and 4 women (age 57...
January 11, 2017: Clinical Cardiology
https://www.readbyqxmd.com/read/28035015/case-studies-in-physiology-maximal-oxygen-consumption-and-performance-in-a-centenarian-cyclist
#20
Véronique Billat, Gilles Dhonneur, Laurence Mille-Hamard, Laurence Le Moyec, Iman Momken, Thierry Launay, Jean Pierre Koralsztein, Sophie Besse
The purpose of this study was to examine the physiological characteristics of an elite centenarian cyclist who, at 101 yr old, established the 1-h cycling record for individuals ≥100 yr old (24.25 km) and to determine the physiological factors associated with his performance improvement 2 yr later at 103 yr old (26.92 km; +11%). Before each record, he performed an incremental test on a cycling ergometer. For 2 yr, he trained 5,000 km/yr with a polarized training that involved cycling 80% of mileage at "light" rate of perceived exertion (RPE) ≤12 and 20% at "hard" RPE ≥15 at a cadence between 50 and 70 rpm...
March 1, 2017: Journal of Applied Physiology
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