scholarly journals Indirect Calorimetry: From Expired CO2 Production, Inspired O2 Consumption to Energy Equivalent

2015 ◽  
Vol s5 ◽  
Author(s):  
Priscila Giacomo
Keyword(s):  
Indirect Calorimetry ◽  
Co2 Production ◽  
O2 Consumption ◽  
Energy Equivalent

Mismatch between lipid mobilization and oxidation: glycerol kinetics in running African goats

1993 ◽  
Vol 264 (4) ◽  
pp. R797-R803 ◽  
Author(s):  
J. M. Weber ◽  
T. J. Roberts ◽  
C. R. Taylor
Keyword(s):  
Fatty Acid ◽  
Aerobic Capacity ◽  
Indirect Calorimetry ◽  
Treadmill Exercise ◽  
Large Fraction ◽  
O2 Consumption ◽  
Glycerol Release ◽  
Intense Exercise ◽  
Lipid Mobilization ◽  
Relative Contribution

Glycerol kinetics and total fatty acid (FA) oxidation of trained African pygmy goats were measured by continuous infusion of [2-3H]glycerol and indirect calorimetry during treadmill exercise at 40, 60, and 85% maximal O2 consumption (VO2max). Our main goals were 1) to determine whether rates of FA mobilization and utilization are eventually matched as exercise intensity increases, thereby minimizing reesterification to supply more FA to working muscles, and 2) to test the hypothesis that lipolytic rate is proportional to aerobic capacity by comparing low-aerobic goats with published values from highly aerobic dogs and humans. Mean rate of glycerol release in the circulation (Ra glycerol) was 3.83 +/- 0.11 at rest, 7.69 +/- 0.88 at 40% VO2max, reached a maximum of 15.32 +/- 0.95 at 60% VO2max, and returned to 10.53 +/- 0.76 mumol.kg-1 x min-1 at 85% VO2max. Lipolytic rate did not match total FA oxidation, implying that Ra glycerol cannot be used as an index of FA utilization, even during intense exercise. A large fraction of total FA released by lipolysis was reesterified at 60 and 85% VO2max, showing that FA mobilization does not limit whole animal FA oxidation at these intensities. Comparing goat, dog, and human responses reveals that mammalian lipolytic rate is scaled with aerobic capacity. High- and low-aerobic species exercising at the same %VO2max mobilize FA in exact proportion with their metabolic rate, suggesting that the relative contribution of FA to total energy provision is independent of VO2max.

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.

Comparison of indirect calorimetry and a new breath 13C/12C ratio method during strenuous exercise

1992 ◽  
Vol 263 (1) ◽  
pp. E64-E71 ◽  
Author(s):  
J. A. Romijn ◽  
E. F. Coyle ◽  
J. Hibbert ◽  
R. R. Wolfe
Keyword(s):  
Indirect Calorimetry ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Co2 Production ◽  
Strenuous Exercise ◽  
Ratio Method ◽  
O2 Uptake ◽  
Underlying Assumption ◽  
Oxidation Rates

A new stable isotope method for the determination of substrate oxidation rates in vivo is described and compared with indirect calorimetry at rest and during high-intensity exercise (30 min at 80-85% maximal O2 uptake capacity) in six well-trained cyclists. This method uses the absolute ratios of 13C/12C in expired air, endogenous glucose, fat, and protein in addition to O2 consumption and is independent of CO2 production (VCO2). Carbohydrate and fat oxidation rates at rest, calculated by both methods, were not significantly different. During exercise the breath 13C/12C ratio increased and reached a steady state after 15-20 min. Carbohydrate oxidation rates during exercise were 39.4 +/- 5.2 and 41.7 +/- 5.7 mg.kg-1.min-1 [not significant (NS)], and fat oxidation rates were 7.3 +/- 1.3 and 6.9 +/- 1.2 mg.kg-1.min-1 (NS), using indirect calorimetry, and the breath ratio method, respectively. We conclude that the breath 13C/12C ratio method can be used to calculate substrate oxidation under different conditions, such as the basal state and exercise. In addition, the results obtained by this new method support the validity of the underlying assumption that indirect calorimetry regards VCO2 as a reflection of tissue CO2 production, during exercise in trained subjects, even up to 80-85% maximal O2 uptake.

Longitudinal Measurements of Resting Energy Expenditure by Indirect Calorimetry in Healthy Term Infants during the First 2 Months of Life

2018 ◽  
Vol 36 (09) ◽  
pp. 918-923
Author(s):  
Sourabh Verma ◽  
Sean M. Bailey ◽  
Pradeep V. Mally ◽  
Heather B. Howell
Keyword(s):  
Pilot Study ◽  
Energy Expenditure ◽  
Indirect Calorimetry ◽  
Resting Energy Expenditure ◽  
Co2 Production ◽  
Term Infants ◽  
Longitudinal Measurements ◽  
Expired Gas ◽  
Carbon Dioxide Co2 ◽  
Resting Energy

Objective To determine longitudinal measurements of resting energy expenditure (REE) by indirect calorimetry (IC) in healthy term infants during the first 2 months of life. Study Design An outpatient prospective pilot study was performed in healthy term infants to estimate REE by measuring expired gas fractions of oxygen (O2) and carbon dioxide (CO2) with IC in a respiratory and metabolic steady state. Results A total of 30 measurements were performed. Fourteen subjects completed measurements at both 1 and 2 months of life, and two subjects had only measurements made at 1 month of life. Mean REE values were 64.1 ± 12.7 and 58.4 ± 14.3 kcal/kg/d at 1 and 2 months of age, respectively. Mean O2 consumption and CO2 production measurements were 9.3 ± 2.0 and 7.7 ± 1.2 mL/kg/min and 8.1 ± 2.2 and 6.4 ± 1.1 mL/kg/min at 1 and 2 months of age, respectively. Conclusion This pilot study demonstrates longitudinal measurements of REE by IC in healthy term infants during the first 2 months of life. We also demonstrate that, overall, there is consistency in REE values in this population, with a likely decrease in individual longitudinal measurements over the first 2 months of life.

scholarly journals CURRENT POSSIBILITIES OF USE OF INDIRECT CALORIMETRY IN PERIOPERATIVE ENERGY MONITORING

2020 ◽  
Vol 2 (12) ◽  
pp. 79-89
Author(s):  
V.I. Cherniy ◽  
A.I. Denysenko
Keyword(s):  
Indirect Calorimetry ◽  
Lung Ventilation ◽  
International Standards ◽  
Low Flow ◽  
Narcotic Analgesics ◽  
Energy Monitoring ◽  
Perioperative Therapy ◽  
Surgical Interventions ◽  
Energy Equivalent ◽  
Arterial Blood

The purpose of the study is to develop a method of perioperative energy monitoring and to implement it in clinical practice. Material and methods. The study involved 125 patients who underwent various surgical interventions under general anesthesia using sevoflurane (inhalation anesthetics) and fentanyl (narcotic analgesics) in low-flow artificial lung ventilation. Methods of perioperative monitoring (International Standards for a Safe Practice of Anesthesia 2010, WFSA) were supplemented using indirect calorimetry. Results. Analyzing the literature data, a close correlation was found between the energy equivalent of oxygen (EEE2) and the respiratory factor (RQ). The authors obtained the corresponding one-factor linear regression formula, which had the form: EEE2 = 1.157 × RQ + 4,037. Using the basic principles of gas exchange in the lungs of Bohr-Engoff, a method of perioperative energy monitoring was developed, based on indirect calorimetry, taking into account the real values ​​of the energy equivalent of patients' oxygen. The universal formula for determining the level of metabolism of the patient (MR, cal / min) in the form of: MR = [0,863 × VE × (PECO2 / PaCO2) × (FiO2 - FeO2)] (1,157 × RQ + 4,037) where, VE - total ventilation of the lungs per minute (ml / min), PECO2, PaCO2 - partial pressure, respectively, in a mixture of gases, which is exhaled and in the arterial blood (mm Hg). FiO2 and FEO2 are the oxygen fraction in the gas mixture that is inhaled and exhaled in units (% / 100). The method is implemented as a computer program created on the basis of the developed formula. The methods of intensive perioperative therapy taking into account the level of metabolism are presented. Conclusion. The method of perioperative energy monitoring substantially complements the "International Standards for Safe Anesthesiology Practice", WFSA (2010) enhances the perioperative safety of patients by detecting metabolic disorders and conducting appropriate pathogenetic correction.

Chloral Hydrate and the Carbon Dioxide Chemoreceptor Response: A Study of Puppies and Infants

PEDIATRICS ◽  
1982 ◽  
Vol 70 (3) ◽  
pp. 447-450
Author(s):  
Martin H. Lees ◽  
George D. Olsen ◽  
Kip L. McGilliard ◽  
James D. Newcomb ◽  
Cecille O. Sunderland
Keyword(s):  
Carbon Dioxide ◽  
Tidal Volume ◽  
Eye Movement ◽  
Chloral Hydrate ◽  
Nrem Sleep ◽  
Co2 Production ◽  
O2 Consumption ◽  
Rapid Eye Movement ◽  
Natural Sleep ◽  
Co2 Elimination

CO2 chemoreceptor function was assessed during natural sleep and following the administration of 100 mg/kg of chloral hydrate to 26 puppies. With chloral hydrate-induced sleep, there were no significant changes in ventilation or in CO2 chemoreceptor response. The ventilation and CO2 chemoreceptor response of a group of infants in natural sleep were compared with those of a group receiving 50 mg/kg of chloral hydrate. Tidal volume, O2 consumption, and CO2 elimination were slightly higher in the group given chloral hydrate. There was no difference in the CO2 chemoreceptor response. The proportion of time spent in rapid eye movement (REM) and non-rapid eye movement (NREM) sleep in chloral hydrate-induced sleep was similar to that occurring in natural sleep. Use of chloral hydrate stabilizes O2 consumption and CO2 production, and it greatly facilitates the assessment of chemoreceptor function in infants. The CO2 chemoreceptor response appears not to be altered in puppies or infants.

Determining energy expenditure in preterm infants: comparison of 2H(2)18O method and indirect calorimetry

1992 ◽  
Vol 263 (3) ◽  
pp. R685-R692 ◽  
Author(s):  
C. L. Jensen ◽  
N. F. Butte ◽  
W. W. Wong ◽  
J. K. Moon
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Preterm Infants ◽  
Indirect Calorimetry ◽  
Water Flux ◽  
High Ratio ◽  
Individual Variability ◽  
Study Time ◽  
Co2 Production ◽  
Turnover Rates

The doubly labeled water (2H(2)18O) method used to estimate total energy expenditure (EETotal) is particularly sensitive to analytic error in preterm infants, because of their high percentage of body water and the high ratio of water flux to CO2 production. To evaluate further use of this method, the EE of 12 preterm infants was measured by indirect calorimetry and 2H(2)18O simultaneously and continuously for 5 days. Initial infant weight, age, and postconceptional age were (means +/- SD) 1,674 +/- 173 g, 4.4 +/- 2.6 wk, and 34.6 +/- 1.6 wk, respectively. The indirect calorimeter system included an air-temperature-controlled chamber and heart rate monitor. EE was measured by indirect calorimetry for 85.6 +/- 4.7% of study time and estimated from the linear regression of heart rate on EE for 14.4 +/- 4.7% of study time. The 2H(2)18O method entailed an initial dose of 100 mg 2H2O and 250 mg 18O/kg and a final dose of 75 mg 18O/kg; urine was collected twice daily. 2H and 18O enrichments were measured by gas-isotope-ratio mass spectrometry. EE was calculated from measured 2H and 18O dilution spaces (NH, NO), turnover rates (kH, kO), and measured respiratory quotient. The ratio of 2H to 18O dilution spaces was 1.01 +/- 0.01 and the ratio of kO to kH was 1.16 +/- 0.04. Estimation of EE from 2H(2)18O and indirect calorimetry agreed within 1%, although individual variability in methods was large.

Fast-response whole body indirect calorimeters for infants

1993 ◽  
Vol 74 (1) ◽  
pp. 476-484 ◽  
Author(s):  
J. K. Moon ◽  
C. L. Jensen ◽  
N. F. Butte
Keyword(s):  
Eye Movement ◽  
Fast Response ◽  
Full Term ◽  
Whole Body ◽  
Co2 Production ◽  
Sleep Stages ◽  
System Response ◽  
O2 Consumption ◽  
Rapid Eye Movement ◽  
Term Infants

Portable whole body indirect calorimeters were constructed for full-term (2.5- to 8-kg) and preterm (1- to 2.5-kg) infants. A new calibration system significantly increased the accuracy of flowmeters and gas analyzers. Performance tests with N2 and CO2 infusions and butane combustion demonstrated that the error of individual measurements of O2 consumption and CO2 production were within +/- 2%. The measured error was close to the theoretical uncertainty of approximately +/- 1% calculated from test results of the flowmeters and gas analyzers. System response to a step change in butane combustion rate exceeded 90% within 2 min. Error of +/- 2% and response of 2 min are likely to be the practical lower limits for whole body infant indirect calorimeters with current technology. The calorimeters demonstrated a rapid increase in O2 consumption after feeding (preterm infants) and in the transition from non-rapid-eye-movement to rapid-eye-movement sleep stages (full-term infants).

Effects of glycogen depletion and work load on postexercise O2 consumption and blood lactate

1979 ◽  
Vol 47 (3) ◽  
pp. 514-521 ◽  
Author(s):  
S. S. Segal ◽  
G. A. Brooks
Keyword(s):  
Blood Lactate ◽  
Slow Component ◽  
Minute Ventilation ◽  
Co2 Flux ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Co2 Production ◽  
O2 Consumption ◽  
Glycogen Depletion ◽  
Heavy Exercise

To study a possible relationship between blood lactate and O2 consumption (VO2) after exercise, 11 male subjects exercised on a bicycle ergometer at moderate and heavy work loads in both normal glycogen and glycogen-depleted states. At rest, glycogen depletion resulted in significantly lowered blood glucose and lactate concentrations, CO2 production (VCO2), respiratory exchange ratio (R), and minute ventilation (VE). With the exception of glucose, these variables changed more in response to heavy exercise (HE: 2 min at a mean of 1,750 kg.m/min) than to moderate exercise (ME: 2 min at a mean of 1,000 kg.m/min). At either work load, VCO2, R, and lactate showed consistently greater responses in the normal glycogen state. The slope of the initial component of the postexercise VO2 curve was unaffected by either work load or lactate. Although the slope of the slow component of the postexercise VO2 curve became significantly more negative after HE, it was unaffected by the level of lactate. These results are inconsistent with the hypothesis of a “lactacid O2 debt.” Exercise intensity was the predominant factor influencing the magnitude and kinetics of postexercise VO2. Glycogen depletion resulted in lower VCO2, R, and blood lactate, but higher VE during heavy exercise. The results suggest that factors, in addition to CO2 flux to the lungs, influence VE during exercise.

Respiratory stimulation by female hormones in awake male rats

1991 ◽  
Vol 71 (1) ◽  
pp. 37-42 ◽  
Author(s):  
K. Tatsumi ◽  
M. Mikami ◽  
T. Kuriyama ◽  
Y. Fukuda
Keyword(s):  
Tidal Volume ◽  
Ventilatory Response ◽  
Blood Gases ◽  
Male Rats ◽  
Co2 Production ◽  
Male Rat ◽  
O2 Consumption ◽  
Estradiol Treatment ◽  
Respiratory Stimulation ◽  
Ventilatory Response To Co2

The respiratory effect of progestin differs among various animal species and humans. The rat does not hyperventilate in response to exogenous progestin. The present study was conducted to determine whether administration of combined progestin and estrogen prompts ventilatory stimulation in the male rat. Ventilation, blood gases, and metabolic rates (O2 consumption and CO2 production) were measured in the awake and unrestrained male Wistar rat. The combined administration of a synthetic potent progestin (TZP4238) and estradiol for 5 days significantly increased tidal volume and minute expiratory ventilation (VE), reduced arterial PCO2, and enhanced the ventilatory response to CO2 inhalation (delta VE/delta PCO2). On the other hand, respiratory frequency, O2 consumption, CO2 production, and body temperature were not affected. The arterial pH increased slightly, with a concomitant decrease in plasma [HCO3-]. Administration of either TZP4238 or estradiol alone or vehicle (Tween 80) had no effect on respiration, blood gases, and ventilatory response to CO2. The results indicated that respiratory stimulation following combined progestin plus estradiol treatment in the male rat involves activation of process(es) that regulate tidal volume and its augmentation during CO2 stimulus.

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