A SYSTEM FOR THE CONTINUOUS MEASUREMENT OF OXYGEN UPTAKE AND CARBON DIOXIDE OUTPUT IN ARTIFICIALLY VENTILATED PATIENTS

Two men ran for 20 or 60 seconds while inhaling air, oxygen or 4% carbon dioxide. Inspired respiratory minute volume was determined for each breath. Ventilation increased suddenly in the first breath with minimal changes in end-expiratory carbon dioxide tension and respiratory exchange ratio to a rate that remained constant for 20 seconds before increasing further. The rate of carbon dioxide output was uniform during the first 20 seconds. A 12% grade did not increase ventilation or oxygen uptake during runs of 20 seconds, but in the first minute of recovery, ventilation was 64% greater than after level runs. Inhalation of oxygen inhibited ventilation by 24% in the 20-second periods before and after the end of a 60-second run. Inhalation of carbon dioxide begun at rest produced increments in ventilation and end-expiratory carbon dioxide tension that varied little during running and recovery. In the 20-second runs ventilation varied with speed but appeared independent of ultimate metabolic cost. Submitted on January 21, 1960

Download Full-text

Use of respiratory quotients in assessment of aerobic work capacity

Journal of Applied Physiology ◽

10.1152/jappl.1962.17.1.47 ◽

1962 ◽

Vol 17 (1) ◽

pp. 47-50 ◽

Cited By ~ 104

Author(s):

B. Issekutz ◽

N. C. Birkhead ◽

K. Rodahl

Keyword(s):

Carbon Dioxide ◽

Oxygen Uptake ◽

Work Load ◽

Work Capacity ◽

Bicycle Ergometer ◽

Carbon Dioxide Output ◽

Ergometer Test ◽

Aerobic Work Capacity ◽

Bicycle Ergometer Test ◽

Better Than

Oxygen uptake and carbon dioxide output were measured in 32 untrained subjects during exercise on the bicycle ergometer. It was shown that the work respiratory quotient (RQ) under standardized conditions can be used as a measure of physical fitness. ΔRQ (work RQ minus 0.75) increases logarithmically with the work load and maximal O2 uptake is reached at a ΔRQ value of 0.40. This observation offered the possibility of predicting the maximal O2 uptake of a person, based on the measurement of RQ during a single bicycle ergometer test at a submaximal load. For each work RQ between 0.95 and 1.15 a factor was presented, together with the aid of a simple equation, which gave a good approximation (generally better than ±10%) of the maximal O2 uptake.

Download Full-text

Intratest reliability and test–retest reproducibility of the oxygen uptake efficiency slope in healthy participants

European Journal of Cardiovascular Prevention & Rehabilitation ◽

10.1097/hjr.0b013e32832c88a8 ◽

2009 ◽

Vol 16 (4) ◽

pp. 493-498 ◽

Cited By ~ 24

Author(s):

Christophe Van Laethem ◽

Johan De Sutter ◽

Wim Peersman ◽

Patrick Calders

Keyword(s):

Carbon Dioxide ◽

Oxygen Uptake ◽

Minute Ventilation ◽

Exercise Duration ◽

Peak Oxygen Uptake ◽

Exercise Tests ◽

Uptake Efficiency ◽

Carbon Dioxide Output ◽

Oxygen Uptake Efficiency Slope ◽

Healthy Participants

Background The oxygen uptake efficiency slope (OUES) is a newer ventilatory exercise parameter, used in the evaluation of healthy participants and patients with cardiovascular disease. However, few data about the reliability and reproducibility of OUES are available. Our study assessed intratest reliability and test-retest reproducibility of OUES in healthy participants. Design and methods Eighteen participants (age 28 ± 6 years, BMI 22.1 ± 1.9 kg/m2, 10 men) performed two identical maximal exercise tests on a bicycle ergometer. To assess test-retest reproducibility, we performed Bland-Altman analysis and calculated the coefficient of repeatability of the main ventilatory variables. Results OUES remained stable during the second part of the exercise test. Mean values varied 2.4 ± 4.0% between OUES calculated at 70% (OUES70) and at 100% of exercise duration. Mean variation decreased to 1.4 ± 2.3% when OUES was calculated at 90% of exercise duration (OUES90). The Bland-Altman 95% limits of agreement for OUES90 were +3 and –6%, those for OUES70 were +11 and –8%. The coefficient of repeatability for OUES was 597 ml/min or 18.7% of the average value of repeated OUES measurements. These results were similar to those of peak oxygen uptake and minute ventilation/carbon dioxide output. However, the test-retest reproducibility for submaximal-derived values of OUES was lower, as we noted higher coefficients of repeatability for OUES90 and OUES70, increasing up to 27% of the average of repeated values. Conclusion OUES shows excellent intratest reliability and has a test-retest reproducibility that is similar to that of peak oxygen uptake and minute ventilation/carbon dioxide output slope. However, its reproducibility becomes higher when it is calculated from increasing levels of achieved exercise intensity.

Download Full-text

Changes in Ventilation, Oxygen Uptake, and Carbon Dioxide Output during Recovery from Isoflurane Anesthesia

Anesthesiology ◽

10.1097/00000542-198905000-00004 ◽

1989 ◽

Vol 70 (5) ◽

pp. 737-741 ◽

Cited By ~ 103

Author(s):

M. J. Clofolo ◽

F. Clergue ◽

C. Devillers ◽

M. Ben Ammar ◽

P. Viars

Keyword(s):

Carbon Dioxide ◽

Oxygen Uptake ◽

Carbon Dioxide Output ◽

Isoflurane Anesthesia

Download Full-text

Physiological responses and air consumption during simulated firefighting tasks in a subway system

Applied Physiology Nutrition and Metabolism ◽

10.1139/h10-061 ◽

2010 ◽

Vol 35 (5) ◽

pp. 671-678 ◽

Cited By ~ 7

Author(s):

F. Michael Williams-Bell ◽

Geoff Boisseau ◽

John McGill ◽

Andrew Kostiuk ◽

Richard L. Hughson

Keyword(s):

Carbon Dioxide ◽

Oxygen Uptake ◽

Energy Requirement ◽

Average Energy ◽

Peak Oxygen Uptake ◽

Search And Rescue ◽

Moderate Intensity ◽

Physiological Strain ◽

Carbon Dioxide Output ◽

Subway System

Professional firefighters (33 men, 3 women), ranging in age from 30 to 53 years, participated in a simulation of a subway system search and rescue while breathing from their self-contained breathing apparatus (SCBA). We tested the hypothesis that during this task, established by expert firefighters to be of moderate intensity, the rate of air consumption would exceed the capacity of a nominal 30-min cylinder. Oxygen uptake, carbon dioxide output, and air consumption were measured with a portable breath-by-breath gas exchange analysis system, which was fully integrated with the expired port of the SCBA. The task involved descending a flight of stairs, walking, performing a search and rescue, retreat walking, then ascending a single flight of stairs to a safe exit. This scenario required between 9:56 and 13:24 min:s (mean, 12:10 ± 1:10 min:s) to complete, with an average oxygen uptake of 24.3 ± 4.5 mL·kg–1·min–1 (47 ± 10 % peak oxygen uptake) and heart rate of 76% ± 7% of maximum. The highest energy requirement was during the final single-flight stair climb (30.4 ± 5.4 mL·kg–1·min–1). The average respiratory exchange ratio (carbon dioxide output/oxygen uptake) throughout the scenario was 0.95 ± 0.08, indicating a high carbon dioxide output for a relatively moderate average energy requirement. Air consumption from the nominal “30-min” cylinder averaged 51% (range, 26%–68%); however, extrapolation of these rates of consumption suggested that the low-air alarm, signalling that only 25% of the air remains, would have occurred as early as 11 min for an individual with the highest rate of air consumption, and at 16 min for the group average. These data suggest that even the moderate physical demands of walking combined with search and rescue while wearing full protective gear and breathing through the SCBA impose considerable physiological strain on professional firefighters. As well, the rate of air consumption in these tasks classed as moderate, compared with high-rise firefighting, would have depleted the air supply well before the nominal time used to describe the cylinders.

Download Full-text

Dependence of mitosis and respiration in roots upon oxygen tension

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1961.0023 ◽

1961 ◽

Vol 154 (954) ◽

pp. 109-129 ◽

Cited By ~ 17

Keyword(s):

Carbon Dioxide ◽

Oxygen Uptake ◽

Oxygen Tension ◽

Oxygen Requirement ◽

Anaerobic Conditions ◽

Root Tips ◽

Carbon Dioxide Output ◽

Lower Oxygen ◽

Oxygen Tensions ◽

The Relationship

Excised pea-root tips were incubated for 4 h in gas mixtures containing 0.00001 to 100% oxygen, in order to determine the effect upon mitosis. Below 0.0005% oxygen, mitosis was completely arrested. Between 0.001 and 0.02% oxygen, cells initially in mitosis completed division, but no more cells started dividing. Between 0.05 and 0.2% oxygen, cells initially in interphase entered division, but did not finish. Above 0.5% oxygen, all cells not prevented from dividing by excision finished division within 4 h. After exposure to 0.05% oxygen for 4 h, an excessive proportion of cells was found in prophase; in 0.1% oxygen an excess of metaphases, and in 0.2% oxygen an excess of telophases resulted. The oxygen uptake and carbon dioxide output of root tips were measured in a range of oxygen tensions and in anaerobic conditions. The relationship between oxygen uptake and oxygen tension was hyperbolic; a half maximum rate of oxygen uptake was obtained at about 10% oxygen. It was concluded that the respiration of root tips was limited by slow diffusion of oxygen through the tissue. From the carbon dioxide output it was estimated that the amount of energy available to isolated root tips under anaerobic conditions was about 1% of that available under aerobic conditions. Possible mechanisms whereby extreme oxygen-lack could arrest mitosis were considered. It was shown that the arrest was not due to abolition of a gross supply of energy. No evidence was obtained as to what other mechanism might be operative. An hypothesis was formulated in an attempt to explain the complicated relationship between mitosis and oxygen tension. It was assumed that the visible phases of mitosis are immediately preceded by a phase with a higher requirement for oxygen than mitosis, and that preceding this is an earlier phase with a lower oxygen requirement than mitosis.

Download Full-text

STUDIES IN THE MODE OF ACTION OF ROYAL JELLY IN HONEYBEE DEVELOPMENT: II. RESPIRATION OF NEWLY EMERGED LARVAE ON VARIOUS SUBSTRATES

Canadian Journal of Zoology ◽

10.1139/z59-081 ◽

1959 ◽

Vol 37 (5) ◽

pp. 803-813 ◽

Cited By ~ 51

Author(s):

R. W. Shuel ◽

S. E. Dixon

Keyword(s):

Carbon Dioxide ◽

Oxygen Uptake ◽

Mode Of Action ◽

Royal Jelly ◽

Water Soluble ◽

Older Worker ◽

Carbon Dioxide Evolution ◽

Carbon Dioxide Output ◽

Nutritional Balance

Measurements were made of oxygen uptake and carbon dioxide evolution, during the first 24 hours of life, by larvae on substrates of different age and type. These substrates included royal jelly, the pharyngeal secretion fed to larvae destined to become queens, which varied in age from 0 to 96 hours; the pharyngeal secretion fed to young larvae destined to be workers, which varied in age from 0 to 60 hours and which was termed "worker jelly"; and the food supplied to older worker larvae, composed of a pharyngeal secretion modified by an admixture of honey and pollen, and termed "modified jelly". The pattern and magnitude of oxygen uptake was similar on all substrates. Net carbon dioxide evolution by larvae on royal jelly or modified jelly was highly positive; net carbon dioxide evolution by larvae on worker jelly was slightly negative. Microchemical analyses showed that royal jelly differed in composition from worker jelly and modified jelly. The composition of royal jelly remained relatively constant with age. The addition of sugars to worker jelly produced an increase in carbon dioxide output which was nullified by the further addition of an extract of the water-soluble acids of royal jelly. The differences observed in carbon dioxide evolution by young larvae on worker jelly and royal jelly are considered to be an expression of the initiation of female dimorphism. An hypothesis of nutritional balance is advanced to account for this dimorphism.

Download Full-text

Metabolism of Exercising and Resting Human Skeletal Muscle, in the Post-Prandial and Fasting States

Clinical Science ◽

10.1042/cs0440479 ◽

1973 ◽

Vol 44 (5) ◽

pp. 479-491 ◽

Cited By ~ 14

Author(s):

Patricia G. B. Baker ◽

R. F. Mottram

Keyword(s):

Carbon Dioxide ◽

Skeletal Muscle ◽

Oxygen Uptake ◽

Glucose Uptake ◽

Maximal Voluntary Contraction ◽

Human Skeletal Muscle ◽

Voluntary Contraction ◽

Contraction Force ◽

Carbon Dioxide Output

1. Methods are described for study of metabolism of human skeletal muscle in situ, at rest and during mild sustained contraction in the fed and fasted states. 2. At rest the average oxygen uptake was 0.29 ml min−1 100 ml of muscle−1 and the carbon dioxide output was 0.22 ml. Glucose uptake was 0.49 mg min−1 100 ml of muscle−1. The respiratory quotient was 0.75, indicating that most of the glucose was being stored. 3. When subjects made hand-grips of 5% of their maximal voluntary contraction force (5% MVC) the oxygen and carbon dioxide exchanges both increased by six times while the glucose uptake increased by 70% of the resting value. 4. A 7 h fast before the observations were made severely decreased both resting and exercising glucose uptake but produced no other alteration in the metabolism of the muscle.

Download Full-text