Quantitative methanol-burning lung model for validating gas-exchange measurements over wide ranges of F I O 2

1998 ◽  
Vol 84 (6) ◽  
pp. 2177-2182 ◽  
Author(s):  
Saul Miodownik ◽  
Jose Melendez ◽  
Vittoria Arslan Carlon ◽  
Brian Burda
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Gas Exchange ◽  
Combustion Rate ◽  
Respiratory Quotient ◽  
Infusion Rate ◽  
Carbon Dioxide Production ◽  
Lung Model ◽  
Burner Device ◽  
Extended Range

The methanol-burning lung model has been used as a technique for generating a predictable ratio of carbon dioxide production (V˙co 2) to oxygen consumption (V˙o 2) or respiratory quotient (RQ). Although an accurate RQ can be generated, quantitatively predictable and adjustableV˙o 2 andV˙co 2 cannot be generated. We describe a new burner device in which the combustion rate of methanol is always equal to the infusion rate of fuel over an extended range of O2 concentrations. This permits the assembly of a methanol-burning lung model that is usable with O2 concentrations up to 100% and provides continuously adjustable and quantitativeV˙o 2 (69–1,525 ml/min) and V˙co 2 (46–1,016 ml/min) at a RQ of 0.667.

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.

scholarly journals The respiratory quotient in the newborn pig

1969 ◽  
Vol 23 (2) ◽  
pp. 407-413 ◽  
Author(s):  
L. E. Mount
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Energy Metabolism ◽  
Respiratory Quotient ◽  
Carbon Dioxide Production ◽  
Mean Value ◽  
Open Circuit ◽  
Mean Values ◽  
The Mean ◽  
Environmental Temperatures

1. Rates of oxygen consumption and carbon dioxide production were measured in pigs from birth to 3 days of age in an open-circuit system.2. The mean respiratory quotient (RQ) during the first 6 h following birth was 0.95 in fasted pigs and 0.91 in pigs which were allowed to feed.3. The RQ fell during the remainder of the first postnatal day to mean values close to 0.85, whether the pigs were allowed to feed from birth or were fasted.4. From 1 to 3 days of age the RQ had a mean value of 0.79.5. There was little difference in the RQ of pigs exposed to environmental temperatures of either 32 or 16°.6. It is concluded that the baby pig is not exclusively dependent on carbohydrate for its energy metabolism.

Measurement of oxygen consumption and carbon dioxide production rates by a tracer-bolus method

1981 ◽  
Vol 50 (4) ◽  
pp. 898-904 ◽  
Author(s):  
J. S. Clark ◽  
A. H. Bigler ◽  
A. Cutillo ◽  
S. Watanabe ◽  
A. D. Renzetti
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Pulmonary Function Tests ◽  
Normal Subjects ◽  
Carbon Dioxide Production ◽  
Lung Model ◽  
Injection System ◽  
Single Compartment ◽  
Perfused Lung ◽  
Standard Gas

A new method for measuring oxygen consumption and carbon dioxide production is described. The method is based on the injection of a helium bolus into the inspired gas for repeated breaths; the helium can be delivered through the mouth or through a nostril (the injection system being controlled by the integrated flow signal or by the signal of a thermistor, respectively). Compared with the conventional gas-collection technique, the tracer-bolus method allows more rapid and frequent measurements. The method does not necessarily require an airtight respiratory circuit, so that it can be conveniently applied in less cooperative subjects, including children. The results of validation studies based on a comparison with the standard gas-collection technique are presented; these results indicate that the measurements by the tracer-bolus method are accurate in normal subjects. In patients with obstructive lung disease, the determinations are associated with a systematic error, which is expected, the tracer-bolus method being based on a single-compartment, uniformly ventilated and perfused lung model; the error is, however, predictable from the degree of functional impairment and can be corrected using equations based on routine pulmonary function tests.

scholarly journals Hyperoxia Reversibly Alters Oxygen Consumption and Metabolism

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Patrick Lauscher ◽  
Sabine Lauscher ◽  
Harry Kertscho ◽  
Oliver Habler ◽  
Jens Meier
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Respiratory Quotient ◽  
Carbon Dioxide Production ◽  
Pure Oxygen ◽  
Whole Body ◽  
Fick Principle ◽  
Methodological Problems ◽  
Hyperoxic Ventilation ◽  
The Impact

Aim. Ventilation with pure oxygen (hyperoxic ventilation: HV) is thought to decrease whole body oxygen consumption (VO2). However, the validity and impact of this phenomenon remain ambiguous; until now, under hyperoxic conditions,VO2has only been determined by the reverse Fick principle, a method with inherent methodological problems. The goal of this study was to determine changes ofVO2, carbon dioxide production (VCO2), and the respiratory quotient (RQ) during normoxic and hyperoxic ventilation, using a metabolic monitor.Methods. After providing signed informed consent and institutional acceptance, 14 healthy volunteers were asked to sequentially breathe room air, pure oxygen, and room air again.VO2, VCO2, RQ, and energy expenditure (EE) were determined by indirect calorimetry using a modified metabolic monitor during HV.Results. HV reducedVO2from 3.4 (3.0/4.0) mL/kg/min to 2.8 (2.5/3.6) mL/kg/min (P<0.05), whereas VCO2remained constant (3.0 [2.6/3.6] mL/kg/min versus 3.0 [2.6/3.5] mL/kg/min, n.s.). After onset of HV, RQ increased from 0.9 (0.8/0.9) to 1.1 (1.0/1.1). Most changes during HV were immediately reversed during subsequent normoxic ventilation.Conclusion. HV not only reducesVO2, but also increases the respiratory quotient. This might be interpreted as an indicator of the substantial metabolic changes induced by HV. However, the impact of this phenomenon requires further study.

FETAL OXYGEN CONSUMPTION, CARBON DIOXIDE PRODUCTION, AND GLUCOSE UPTAKE IN A CHRONIC SHEEP PREPARATION

PEDIATRICS ◽  
1972 ◽  
Vol 50 (3) ◽  
pp. 361-371
Author(s):  
Elizabeth J. James ◽  
John R. Raye ◽  
Edwin L. Gresham ◽  
Edgar L. Makowski ◽  
Giacomo Meschia ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Glucose Uptake ◽  
Glucose Concentration ◽  
Respiratory Quotient ◽  
Carbon Dioxide Production ◽  
Concentration Difference ◽  
Umbilical Blood ◽  
Arterial Blood ◽  
Arterial Glucose

Metabolic studies were carried out in 22 sheep fetuses free of operative stress. The studies included measurements of umbilical blood flow (175 ± 8 ml/min/kg), fetal oxygen consumption (5.99 ± 0.15 ml/min/kg), carbon dioxide production (5.65 ± 0.17 ml/min/kg), glucose uptake (3.06 ± 0.28 mg/min/kg), respiratory quotient (0.94 ± 0.01), and glucose/oxygen quotient·(0.41 ± 0.03). The studies demonstrated that fetal glucose uptake could be correlated with the glucose concentration difference betsveen maternal arterial and fetal umbilical arterial blood, as well as with maternal arterial glucose concentration. Umbilical arterial glucose concentration was a function of maternal arterial concentration over the concentration range studied. The study demonstrates that the fetal respiratory quotient is significantly less than one. These data suggest that the accumulation of carbon in the fetus for growth represents approximately 40% of the carbon intake in the growing fetal lamb.

scholarly journals The Relative Efficiency of Gaseous Exchange Across the Lungs and Gills of an African Lungfish Protopterus Aethiopicus

1970 ◽  
Vol 52 (1) ◽  
pp. 1-15
Author(s):  
B. R. McMAHON
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Gas Exchange ◽  
Direct Measurement ◽  
Relative Efficiency ◽  
Lung Ventilation ◽  
Carbon Dioxide Production ◽  
Gaseous Exchange ◽  
Terrestrial Vertebrates ◽  
African Lungfish

1. The efficiency of gas exchange over the lung and gill surfaces of Protopterus has been investigated. 2. Animals confined in water or in air showed an increased respiratory frequency in the remaining medium, indicating that both routes were important in the total gas exchange. 3. Direct measurement of the oxygen and carbon dioxide tensions of pulmonary air and inspired and expired branchial water showed gas exchange ratios (R) of 0.2 for the lung and 5.0 for the gills approximately, demonstrating that more oxygen was consumed via the lungs and more carbon dioxide excreted via the gills. 4. Oxygen consumption and carbon dioxide production were measured directly in a respirometer in which respiratory air and water streams could be kept separate except during lung ventilation. At least 90% of the animals' oxygen consumption occurred in the lung, while 60 % of the carbon dioxide excreted passed via the aquatic route. 5. The results are discussed with reference to the animals' adaptation to its environment and with reference to the evolution of the terrestrial vertebrates.

scholarly journals The influence of temperature on the metabolic regulation and gas exchange of the Highveld scorpion, Opistophthalmus latimanus ( Koch ) ( Scorpionidae )

2012 ◽  
Vol 31 (1) ◽  
Author(s):  
Willie J. Van Aardt ◽  
Japie Mienie ◽  
J.M. Le Roux
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Gas Exchange ◽  
Oxygen Consumption Rate ◽  
Metabolic Regulation ◽  
Consumption Rate ◽  
Carbon Dioxide Production ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Carbon Dioxide Production Rate

Adult scorpions (2.4g – 4.5 kg) were collected near Potchefstroom (26° .55’10” – 27° 10” 5”). Oxygen consumption rate (MO2) and carbon dioxide production rate (MCO2) were measured together with the metabolism of injected radioactive glucose.

scholarly journals The Energetic and Metabolic Effect of Ringerfundin (B. Braun) Infusion and Comparison with Plasma-Lyte (Baxter) in Healthy Volunteers

2010 ◽  
Vol 53 (3) ◽  
pp. 131-137 ◽  
Author(s):  
Zdeněk Zadák ◽  
Radomír Hyšpler ◽  
Miloslav Hronek ◽  
Alena Tichá
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Total Energy ◽  
Healthy Volunteers ◽  
Respiratory Quotient ◽  
Energy Requirement ◽  
Carbon Dioxide Production ◽  
Metabolic Effect ◽  
Ionic Solution ◽  
Rate Of Oxygen Consumption

Measurement of parameters of energy requirement, respiratory quotient (RQ), rate of oxygen consumption (VO2) and rate of carbon dioxide production (VCO2) reveal Ringerfundin as an excellent and metabolically stable-acting balanced ionic solution, which does not increase the consumption of O2 or the total energy requirement. In conclusion, Ringerfundin was very well tolerated and in no case were observed undesirable effects.

Alterations in ventilation and gas exchange during exercise-induced carbohydrate depletion

1979 ◽  
Vol 57 (6) ◽  
pp. 615-618 ◽  
Author(s):  
H. Green ◽  
M. Houston ◽  
J. Thomson ◽  
P. Reid
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Gas Exchange ◽  
Respiratory Exchange Ratio ◽  
Treadmill Exercise ◽  
Carbon Dioxide Production ◽  
Progressive Reduction ◽  
Energy Substrate ◽  
Carbohydrate Depletion ◽  
Exercise Induced

The relationships between ventilation [Formula: see text], oxygen consumption [Formula: see text], and carbon dioxide production [Formula: see text] during work were studied in four trained males during exercise-induced carbohydrate depletion. Repeated bouts of heavy treadmill exercise (6 min at 95% [Formula: see text]max) were performed once per hour for 24 h in order to promote a shift in energy substrate from carbohydrate to fat. Measurements of [Formula: see text] and [Formula: see text] recorded during each minute indicated that [Formula: see text] was unaffected by the number of runs, whereas [Formula: see text] showed a progressive reduction which amounted to 24% during the final run. A corresponding decline of 19% was observed in the respiratory exchange ratio. No significant change in [Formula: see text] occurred between any of the runs. It is concluded that during heavy, repeated, muscular exercise, reductions in [Formula: see text], strongly suggestive of an increased fat oxidation, are not accompanied by a corresponding change in ventilation.

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