Arterial oxygen desaturation during treadmill and bicycle exercise in patients with chronic obstructive airways disease

1985 ◽  
Vol 68 (3) ◽  
pp. 327-332 ◽  
Author(s):  
A. Cockcroft ◽  
A. Beaumont ◽  
L. Adams ◽  
A. Guz
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Carbon Dioxide Production ◽  
Arterial Oxygen ◽  
Chronic Obstructive ◽  
Bicycle Exercise ◽  
Arterial Lactate ◽  
Exercise Ventilation ◽  
Obstructive Airways Disease ◽  
Chronic Obstructive Airways Disease

1. Nine men with severe chronic obstructive airways disease (COAD), known to desaturate on exercise, performed a 6 min self-paced walk on a treadmill, followed by a bicycle exercise with workloads adjusted to mimic the oxygen consumption achieved on the treadmill. During both exercises, ventilation, oxygen consumption, carbon dioxide production, Pao2, Paco2, pH and arterial lactate were measured and subjective breathlessness recorded. 2. A reasonable match of oxygen consumption between the two exercises was achieved. In all subjects Pao2 fell to a lower level during treadmill compared with bicycle exercise. Ventilation, carbon dioxide production and arterial lactate were higher during bicycle exercise. Subjective breathlessness was greater during bicycle exercise, in proportion to the higher ventilation on the bicycle. 3. The greater anaerobiosis occurring on the bicycle led to acidosis and an increased ventilation, minimizing the exercise fall in Pao2. 4. Bicycle testing may seriously underestimate exercise desaturation occurring during level walking in patients with severe COAD.

Arterial oxygen saturation and breathlessness in patients with chronic obstructive airways disease

1987 ◽  
Vol 72 (6) ◽  
pp. 693-698 ◽  
Author(s):  
R. Lane ◽  
A. Cockcroft ◽  
L. Adams ◽  
A. Guz
Keyword(s):  
Visual Analogue Scale ◽  
Analogue Scale ◽  
Arterial Oxygen Saturation ◽  
Supplemental Oxygen ◽  
Arterial Oxygen ◽  
Chronic Obstructive ◽  
Exercise Ventilation ◽  
Vas Scores ◽  
Obstructive Airways Disease ◽  
Chronic Obstructive Airways Disease

1. Nine patients with chronic obstructive airways disease performed a 6 min self-paced walk (breathing air) on a treadmill and then identical (but operator-controlled) treadmill walks breathing either air or supplemental oxygen sufficient to just prevent arterial oxygen desaturation during the exercise. 2. During the exercises, ventilation was recorded and patients recorded their sensation of breathlessness on a visual analogue scale (VAS) every 30 s. 3. Breathing supplemental oxygen produced a small fall in mean exercise ventilation and a large and consistent reduction in mean exercise breathlessness. In seven patients the VAS scores were higher on air than with supplemental oxygen, at similar levels of ventilation. An analysis of co-variance, to control for reduction in ventilation, showed a decrease in mean breathlessness when breathing supplemental oxygen, significant at the 8% level. 4. The reduction in breathlessness produced by preventing exercise desaturation cannot be explained by the decrease in ventilation. This suggests that hypoxia may be a stimulus for breathlessness. The mechanism is unknown.

Factors Determining the Ventilatory Response to Carbon Dioxide in Chronic Obstructive Airways Disease

1970 ◽  
Vol 39 (5) ◽  
pp. 653-662 ◽  
Author(s):  
T. K. C. King ◽  
D. Yu
Keyword(s):  
Carbon Dioxide ◽  
Response Curve ◽  
Ventilatory Response ◽  
Chronic Obstructive ◽  
Co2 Response ◽  
Arterial Pco2 ◽  
Obstructive Airways Disease ◽  
End Tidal ◽  
Chronic Obstructive Airways Disease ◽  
Carbon Dioxide Response

1. The ventilatory response to carbon dioxide was measured in a group of patients with chronic obstructive airways disease using a rebreathing method. 2. The slope of the carbon dioxide response curve was obtained by plotting the ventilation at successive half minutes against the corresponding mean end tidal Pco2. 3. The slope of the carbon dioxide response curve was positively correlated with (a) the FEV1 and (b) the reciprocal of the resting arterial Pco2, both these correlations being statistically significant. 4. Reference to FEV1 alone could explain more than 80% of the variation in the slope of the CO2 response curve. This explained variation was not significantly improved by the additional consideration of the resting arterial Pco2. 5. It was suggested that whatever the underlying complex mechanisms that determine the response to CO2, the FEV1 can be used as an empirical factor for the prediction of this response in patients with chronic obstructive airways disease.

Metabolism during normoxia, hyperoxia, and recovery in newborn rats

1992 ◽  
Vol 70 (3) ◽  
pp. 408-411 ◽  
Author(s):  
Peter B. Frappell ◽  
Andrea Dotta ◽  
Jacopo P. Mortola
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Carbon Dioxide Production ◽  
Oxygen Availability ◽  
Aerobic Metabolism ◽  
Newborn Rats ◽  
Ambient Temperatures ◽  
Positive Effects

Aerobic metabolism (oxygen consumption, [Formula: see text], and carbon dioxide production, [Formula: see text]) has been measured in newborn rats at 2 days of age during normoxia, 30 min of hyperoxia (100% O2) and an additional 30 min of recovery in normoxia at ambient temperatures of 35 °C (thermoneutrality) or 30 °C. In normoxia, at 30 °C [Formula: see text] was higher than at 35 °C. With hyperoxia, [Formula: see text] increased in all cases, but more so at 30 °C (+20%) than at 35 °C (+9%). Upon return to normoxia, metabolism readily returned to the prehyperoxic value. The results support the concept that the normoxic metabolic rate of the newborn can be limited by the availability of oxygen. At temperatures below thermoneutrality the higher metabolic needs aggravate the limitation in oxygen availability, and the positive effects of hyperoxia on [Formula: see text] are therefore more apparent.Key words: neonatal respiration, oxygen consumption, thermoregulation.

GASEOUS METABOLISM IN PREMATURE INFANTS AT 32-34°C AMBIENT TEMPERATURE

PEDIATRICS ◽  
1964 ◽  
Vol 33 (1) ◽  
pp. 75-82
Author(s):  
Forrest H. Adams ◽  
Tetsuro Fujiwara ◽  
Robert Spears ◽  
Joan Hodgman
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Premature Infants ◽  
Rectal Temperature ◽  
Respiratory Quotient ◽  
Carbon Dioxide Production ◽  
Open Circuit ◽  
Co2 Production ◽  
O2 Consumption ◽  
Rate Of Increase

Thirty-four measurements of oxygen consumption, carbon dioxide production, respiratory quotient, and rectal temperature were made on 22 premature infants with ages ranging from 2½ hours to 18 days. The studies were conducted at 32-34°C utilizing an open circuit apparatus and a specially designed climatized chamber. Oxygen consumption and carbon dioxide production were lowest in the first 12 hours and increased thereafter. The rate of increase in O2 consumption was greater than that of CO2 production, with a consequent fall in respiratory quotient during the first 76 hours of life. A reverse relation of O2 consumption and CO2 production was found following the 4th day of life with a consequent rise in respiratory quotient. There was a close correlation between O2 consumption and rectal temperature regardless of age. A respiratory quotient below the value of 0.707 for fat metabolism was observed in 7 premature infants with ages ranging from 24 to 76 hours.

Review paper on Bronchiectasis

1970 ◽  
Vol 1 (1) ◽  
pp. 39-42
Author(s):  
Sudhir Lohani
Keyword(s):  
Internal Medicine ◽  
Chronic Infection ◽  
Review Paper ◽  
Management Strategies ◽  
Airflow Limitation ◽  
Chronic Obstructive ◽  
Obstructive Airways Disease ◽  
Chronic Obstructive Airways Disease

Bronchiectasis is characterized by dilatation of bronchi, airflow limitation and chronic infection/ inflammation. The aetiology, pathology and management are discussed in this review. It is vital that we distinguish bronchiectasis from other obstructive airways disease like Asthma and Chronic obstructive airways disease as management strategies are different. DOI: http://dx.doi.org/10.3126/jaim.v1i1.5839 Journal of Advances in Internal Medicine. 2012; 1(1): 39-42

Measurement of ‘Basal’ and Total Metabolism in Hereditarily Obese-Hyperglycemic Mice

1958 ◽  
Vol 193 (3) ◽  
pp. 495-498 ◽  
Author(s):  
Ruth McClintock ◽  
Nathan Lifson
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Voluntary Movement ◽  
Carbon Dioxide Production ◽  
Open Circuit ◽  
Energy Output ◽  
Obese Mice ◽  
Energy Expenditures ◽  
Isotope Method

Measurements of oxygen consumption and carbon dioxide production were made by the Haldane open circuit method on hereditarily obese mice and littermate controls, and the energy expenditures were estimated. Studies were made on mice for short periods under ‘basal’ conditions, and for periods of approximately a day with the mice fasted and confined, fasted and relatively unconfined, and fed and unconfined. The total energy expenditures of fed and unconfined obese mice were found to be higher than those of nonobese littermate controls by virtue of a) increased ‘basal metabolism’, b) greater energy expenditure associated with feeding, and possibly c) larger energy output for activity despite reduced voluntary movement. The values obtained for total metabolism confirm those previously determined by an isotope method for measuring CO2 output.

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