Comparative physiological study of arbutamine with exercise in humans

2000 ◽  
Vol 98 (4) ◽  
pp. 489-494 ◽  
Author(s):  
Sharon L. LOVELL ◽  
Suzanne M. MAGUIRE ◽  
Frances TURTLE ◽  
Garry McDOWELL ◽  
Norman P. S. CAMPBELL ◽  
...  
Keyword(s):  
Minute Ventilation ◽  
Volume Ratio ◽  
Serum Lactate ◽  
Gas Analysis ◽  
Pharmacological Stress ◽  
Direct Stimulation ◽  
Oxygen Pulse ◽  
Pharmacological Stress Testing ◽  
Artery Disease ◽  
End Tidal

Pharmacological stress testing may be used in the diagnosis of coronary artery disease when there are contra-indications to the use of conventional exercise protocols.The responses to such testing using arbutamine and to conventional treadmill exercise were compared in eight patients. Respiratory gas analysis and cardiovascular observations were performed during both tests. For an equivalent increment in heart rate, both protocols increased systolic blood pressure and serum lactate. Minute ventilation and oxygen consumption also rose during both protocols, but much more so with exercise. The end-tidal partial pressure of CO2 [35.1 (S.D. 3.1) to 30.8 (6.6) mmHg] and the dead space/tidal volume ratio (VD/VT) [0.37 (0.09) to 0.33 (0.08)] fell significantly during arbutamine infusion, but the respiratory exchange ratio did not change during either protocol. Oxygen pulse, a marker of stroke volume, did not change significantly after arbutamine, but rose markedly after exercise [arbutamine, 3.9 (1.1) to 3.37 (0.7) ml·min-1·beat-1; exercise, 4.7 (1.4) to 16.1 (4.6) ml·min-1·beat-1 (P < 0.0001 compared with baseline); difference between peak responses: P < 0.0001]. We conclude that arbutamine simulates some of the physiological responses to exercise, although a number of these responses are less marked than during conventional exercise, in particular cardiac output (oxygen pulse). An increase in ventilation is produced, possibly due to direct stimulation of arterial chemoreceptors. These data suggest that the main action of arbutamine is to increase central drive rather than to establish peripheral demand.

Cardiorespiratory Changes During Prolonged Downhill Versus Uphill Treadmill Exercise

2019 ◽  
Vol 41 (02) ◽  
pp. 69-74 ◽  
Author(s):  
Yoann Garnier ◽  
Romuald Lepers ◽  
Hervé Assadi ◽  
Christos Paizis
Keyword(s):  
Treadmill Exercise ◽  
Minute Ventilation ◽  
Force Production ◽  
Oxygen Pulse ◽  
Cardiorespiratory Response ◽  
Downhill Exercise ◽  
Ventilation Pattern ◽  
Neural Factors ◽  
Level 1 ◽  
End Tidal

AbstractOxygen uptake (V̇O2), heart rate (HR), energy cost (EC) and oxygen pulse are lower during downhill compared to level or uphill locomotion. However, a change in oxygen pulse and EC during prolonged grade exercise is not well documented. This study investigated changes in cardiorespiratory responses and EC during 45-min grade exercises. Nine male healthy volunteers randomly ran at 75% HR reserve during 45-min exercise in a level (+1%), uphill (+15%) or downhill (−15%) condition. V̇O2 , minute ventilation (V̇E ) and end-tidal carbon dioxide (PetCO2) were recorded continuously with 5-min averaging between the 10th and 15th min (T1) and 40th and 45th min (T2). For a similar HR (157±3 bpm), V̇O2 , V̇E , and PetCO2 were lower during downhill compared to level and uphill conditions (p<0.01). V̇O2 and V̇E decreased similarly from T1 to T2 for all conditions (all p<0.01), while PetCO2 decreased only for the downhill condition (p<0.001). Uphill exercise required greater EC compared to level and downhill exercises. EC decreased only during the uphill condition between T1 and T2 (p<0.01). The lowest V̇O2 and EC during downhill exercise compared to uphill and level exercises suggests the involvement of passive elastic structures in force production during downhill. The lower cardiorespiratory response and the reduction in PetCO2 during downhill running exercise, while EC remained constant, suggests an overdrive ventilation pattern likely due to a greater stimulation of efferent neural factors.

scholarly journals Acetazolamide reduces exercise capacity following a five-day ascent to 4559 m on Monte Rosa

2017 ◽  
Author(s):  
Arthur R. Bradwell ◽  
Kimberly Ashdown ◽  
Carla Gallagher ◽  
John Delamere ◽  
Owen D. Thomas ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Minute Ventilation ◽  
Acute Mountain Sickness ◽  
Bicycle Ergometer ◽  
Gas Analysis ◽  
Base Line ◽  
Older Individuals ◽  
Double Blind ◽  
Age Related ◽  
End Tidal

Acetazolamide (Az) is widely used to prevent and treat the symptoms of acute mountain sickness (AMS) but whether it alters exercise capacity at high altitude is unclear. Az (250 mg twice daily) or placebo were administered to 20 healthy adults (age range, 21-77 years) in a double-blind, randomized manner. Participants ascended over five days to 4559 m, before undertaking an incremental exercise test to exhaustion on a bicycle ergometer, with breath-by-breath gas measurements recorded using a portable gas analysis system. Maximum power output (Pmax) was reduced on Az compared with placebo (p=0.03), as was maximum O2 uptake (VO2max) (20.7 vs 24.6 mL/kg/min; p=0.06) and maximum expired CO2 (VCO2max) (23.4 vs 29.5 mL/kg/min; p=0.01). Comparing individuals matched for similar characteristics, Az-treated participants had smaller changes than placebo-treated participants in minute ventilation (88 vs 116 L/min: p=0.05), end tidal O2 (6.6 vs 9.3 mm Hg: p=0.009), end-tidal CO2 (−2.3 vs −4.2 mm Hg: p=0.005), VO2max (9.8 vs 13.8 mL/kg/min; p=0.04) and VCO2max (14.7 vs 20.8 mL/kg/min; p=0.009). There was a negative correlation between the mean ages of paired vs placebo-treated individuals and differences in Pmax reductions from base-line to altitude (r =−0.83: p<0.005) and HRmax at altitude (r=−0.71; p=0.01). Glomerular filtration rate (measured at sea-level) declined with increasing age (r=−0.69; p=0.001). Thus, 250mg of Az twice daily reduced exercise performance, particularly in older individuals. The age-related effects of Az may reflect higher tissue concentrations due to reduced drug clearance in older people.

Optimal pharmacological stress testing for the diagnosis of coronary artery disease: a probabilistic approach

1995 ◽  
Vol 16 (suppl M) ◽  
pp. 3-10 ◽  
Author(s):  
M. L. Geleijnse ◽  
T. H. Marwick ◽  
E. Boersma ◽  
J. W. Deckers ◽  
J. A. Melin ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Stress Testing ◽  
Probabilistic Approach ◽  
Pharmacological Stress ◽  
Pharmacological Stress Testing ◽  
Artery Disease

Pharmacologic Stress Testing

2015 ◽  
Author(s):  
Ankur Gupta ◽  
Gilbert J. Zoghbi ◽  
Fadi G. Hage
Keyword(s):  
Patient Management ◽  
Stress Testing ◽  
Maximal Exercise ◽  
Significant Coronary Artery Disease ◽  
Pharmacologic Stress ◽  
Pharmacological Stress ◽  
Stress Agent ◽  
Pharmacological Stress Testing ◽  
Artery Disease ◽  
Coronary Artery Disease Detection

Pharmacological stress testing plays an important role in patient management. Pharmacologic stress agents (adenosine, dipyridamole, regadenoson, dobutamine) produce coronary hyperemia, which is at least as high as that achieved by maximal exercise, by a completely different set of mechanisms than that achieved during exercise. Regadenoson, a relatively newer agent, offers ease of administration and fewer side effects than older stress agents and has become the agent of choice in many stress laboratories. The choice of the stress agent should be individualized based on its indications, contraindications and safety profile. The diagnostic accuracy of pharmacological stress testing for significant coronary artery disease detection is comparable to or exceeds that of exercise myocardial perfusion imaging.

scholarly journals Association between ventilatory efficiency, oxygen uptake, and Glittre-ADL test results in patients with chronic heart failure: a preliminary study

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Hebert Olímpio Júnior ◽  
Agnaldo José Lopes ◽  
Fernando Silva Guimarães ◽  
Sergio Luiz Soares Marcos da Cunha Chermont ◽  
Sara Lúcia Silveira de Menezes
Keyword(s):  
Heart Failure ◽  
New York ◽  
Chronic Heart Failure ◽  
Functional Capacity ◽  
Treatment Plan ◽  
Minute Ventilation ◽  
Heart Association ◽  
Gas Analysis ◽  
Ventilatory Efficiency ◽  
Scale Scores

Abstract Objective The Glittre-ADL test (GA-T) is a functional capacity test that stands out for encompassing multiple tasks similar to activities of daily living. As ventilatory efficiency is one of the variables valued in the prognosis of chronic heart failure (CHF), this study aimed to evaluate associations between functional capacity and ventilatory variables in patients with CHF during the GA-T. Results Eight patients with CHF and New York Heart Association (NYHA) functional classification II–III underwent the GA-T coupled with metabolic gas analysis to obtain data by means of telemetry. The median total GA-T time was 00:04:39 (00:03:29–00:05:53). Borg dyspnoea scale scores before and after the GA-T were 2 (0–9) and 3 (1–10), respectively (P = 0.011). The relationship between the regression slope relating minute ventilation to carbon dioxide output (VE/VCO2 slope) was correlated with the total GA-T time (rs = 0.714, P = 0.047) and Borg dyspnoea score (rs = 0.761, P = 0.028). The other ventilatory variables showed no significant correlations. Our results suggest that the total GA-T time can be applied to estimate the ventilatory efficiency of patients with CHF. Future studies may use the GA-T in conjunction with other functional capacity tests to guide the treatment plan and evaluate the prognosis.

Upper airway muscle responsiveness to rising Pco 2 during NREM sleep

2000 ◽  
Vol 89 (4) ◽  
pp. 1275-1282 ◽  
Author(s):  
Giora Pillar ◽  
Atul Malhotra ◽  
Robert B. Fogel ◽  
Josee Beauregard ◽  
David I. Slamowitz ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Slow Wave Sleep ◽  
Minute Ventilation ◽  
Upper Airway ◽  
Nrem Sleep ◽  
Dilator Muscle ◽  
Pharyngeal Muscles ◽  
Stage 2 Sleep ◽  
Significant Change ◽  
End Tidal

Although pharyngeal muscles respond robustly to increasing Pco 2 during wakefulness, the effect of hypercapnia on upper airway muscle activation during sleep has not been carefully assessed. This may be important, because it has been hypothesized that CO2-driven muscle activation may importantly stabilize the upper airway during stages 3 and 4 sleep. To test this hypothesis, we measured ventilation, airway resistance, genioglossus (GG) and tensor palatini (TP) electromyogram (EMG), plus end-tidal Pco 2(Pet CO2 ) in 18 subjects during wakefulness, stage 2, and slow-wave sleep (SWS). Responses of ventilation and muscle EMG to administered CO2(Pet CO2 = 6 Torr above the eupneic level) were also assessed during SWS ( n = 9) or stage 2 sleep ( n = 7). Pet CO2 increased spontaneously by 0.8 ± 0.1 Torr from stage 2 to SWS (from 43.3 ± 0.6 to 44.1 ± 0.5 Torr, P < 0.05), with no significant change in GG or TP EMG. Despite a significant increase in minute ventilation with induced hypercapnia (from 8.3 ± 0.1 to 11.9 ± 0.3 l/min in stage 2 and 8.6 ± 0.4 to 12.7 ± 0.4 l/min in SWS, P < 0.05 for both), there was no significant change in the GG or TP EMG. These data indicate that supraphysiological levels of Pet CO2 (50.4 ± 1.6 Torr in stage 2, and 50.4 ± 0.9 Torr in SWS) are not a major independent stimulus to pharyngeal dilator muscle activation during either SWS or stage 2 sleep. Thus hypercapnia-induced pharyngeal dilator muscle activation alone is unlikely to explain the paucity of sleep-disordered breathing events during SWS.

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