Continuous Measurement Of Oxygen Consumption Research Articles

Instrumentation for the continuous measurement of gas exchange and ventilation of infants during assisted ventilation.

A system of instrumentation for continuous measurement of oxygen consumption (VO2), carbon dioxide production (VCO2) and minute ventilation (V1) in human newborns on assisted ventilation is described. VO2 and VCO2 are measured by open-circuit indirect calorimetry utilizing a Servomex OA 184 differential paramagnetic oxygen analyzer and a Beckman LB 2 infrared CO2 analyzer. Minute volume is measured with a body plethysmograph. Bench performance is described, limitations of the system are defined, and sample clinical data are presented. The instrumentation can measure safely, accurately, and continuously physiologic variables in sick infants on assisted ventilation.

Continuous and Simultaneous On-Line Measurements of &OV0312;o2 and &OV0312;co2 during Endotracheal Anesthesia

A single method was developed for the continuous measurement of oxygen consumption (VO2) and carbon dioxide production (VCO2) during endotracheal anesthesia. The total vented flow from a Bain circuit was measured during anesthesia in 28 adult patients and was found to attain at least 97% of a 6-L/min fresh gas inflow (FGI). Therefore, the circuit overflow was assumed to approximate the FGI. Total volume of vented oxygen was calculated by multiplying FGI by oxygen concentration in the vented (mixed expired) gas. VO2 was assessed as the difference between the oxygen volumes entering and leaving the circuit. VCO2 was derived from the product of FGI and mixed expired CO2 concentration. VO2 measured on the Bain circuit correlated with measurements made on a non-breathing circuit (n = 60 pairs, r = 0.99). A good correlation was also found between VCO2 obtained on both circuits (n = 60 pairs, r = 0.99).

An accurate method for the continuous measurement of oxygen consumption in infants during cardiac catheterization.

This paper describes the assessment of a method for measuring the oxygen consumption of infants and young children that is suitable for use in the cardiac catheterization laboratory. It is based upon the open-circuit technique and permits the continuous display of the oxygen consumption during the investigative procedures. The accuracy of the apparatus was assessed over the range 40-200 ml/min, both in vitro and in vivo. It was found that the apparatus was free from systematic error and that it had a random error of approximately 2% of the measured value.

Role of copper dimers and the participation of copper(III) in the copper-catalysed autoxidation of ascorbic acid. Part II. Kinetics and mechanism in 0.100 mol dm–3potassium nitrate

The kinetics of the copper(II)-catalysed oxidation of ascorbic acid by molecular oxygen have been investigated in the range pH 1.80–5.00 using 0.100 mol dm–3 KCl as background electrolyte. The reaction was followed both by continuous measurement of oxygen consumption (using a Clark-type oxygen-sensitive electrode) and by direct spectrophotometric measurement (on samples) of the unchanged ascorbic acid. At constant [H+] the rate law conforms to (i) where [L]T is the total concentration of ascorbic acid and [Cu]T is the total concen-, –d[L]T/dt=–d[O2]/dt=k[Cu]T[L]T½[O2]½(i) tration of CuII. On the basis of this, and on thermodynamic evidence, a chain mechanism is proposed in which a copper–copper binuclear species (containing both ascorbate and chloride ligands) is the reactive species. The dependence on [H+] is too complex, however, to be fully explained. Both one- and two-electron transfer mechanisms are discussed and preference is shown for that involving an initial two-electron transfer to the dioxygen and consequently to the participation of what is formally CuIII.

The Purkinje-muscle junction: A determinant of proximal bundle branch action potential duration

The Purkinje-muscle junction: A determinant of proximal bundle branch action potential duration

An automatic, closed-circuit oxygen consumption apparatus for small animals.

An apparatus suitable for the continuous measurement of oxygen consumption of rats and mice is described. The system uses a motorized syringe dispenser to deliver fixed volumes of oxygen to a closed animal chamber. The dispenser is controlled by a micro-differential pressure switch to maintain chamber pressure slightly above ambient. The rate of oxygen consumption is determined by timing the interval between successive operations of the dispenser. The system has proved suitable for a range of experimental conditions and treatments.

Studies in Experimental Animals on Disseminated Intravascular Coagulation (DIC)

Changes in the clotting system, as well as morphological and functional alterations corresponding to that of the pathologic phenomenon of disseminated intravascular coagulation (DIC) or consumption coagulopathy, were produced by thrombin infusion (550 NIH U X kg-1 X h-1) in rats and simultaneous inhibition of fibrinolysis by PAMBA (100 mg/kg). Changes in the fibrinogen level and platelet count as well as the appearances of fibrin monomers and the formation of microthrombi in several organs were evaluated. Simultaneously, the function of the respiratory system was investigated by continuous measurement of oxygen consumption as well as elasticity and water content of the lung. From the time course of the alterations in the several parameters, conclusions can be drawn for the pathogenesis and the possible therapeutic influence on DIC.

A method for the continuous measurement of oxygen comsumption.

ArticleA method for the continuous measurement of oxygen comsumption.C T Kappagoda, J B Stoker, and R J LindenC T Kappagoda, J B Stoker, and R J LindenPublished Online:01 Oct 1974https://doi.org/10.1152/jappl.1974.37.4.604MoreSectionsPDF (765 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByChemical Measurement13 April 2011Serum tumour necrosis factor alpha and insulin resistance in gastrointestinal cancer8 December 2005 | British Journal of Surgery, Vol. 79, No. 12The performance of a variable-flow indirect calorimeter1 January 1999 | Physiological Measurement, Vol. 17, No. 1Indirect CalorimetryMetabolic Measurements in the Critically IllCritical Care Clinics, Vol. 11, No. 1Loss of exercise training‐induced bradycardia with continued improvement in fitness1 February 2008 | Journal of Sports Sciences, Vol. 12, No. 5A Single, Accurate Measurement of Resting Metabolic Expenditure2 July 2016 | Journal of Parenteral and Enteral Nutrition, Vol. 15, No. 3Protein status and metabolic expenditure determine the response to intravenous nutrition - a new classification of surgical malnutritionBritish Journal of Surgery, Vol. 78, No. 1Measurement of Energy Expenditure in Man: A Review of Available Methods13 July 2009 | Journal of Nutritional Medicine, Vol. 1, No. 4Influence of Energy Source upon Body Composition in Patients Receiving Intravenous Nutrition2 July 2016 | Journal of Parenteral and Enteral Nutrition, Vol. 13, No. 5Energy Measurements and Requirements of Critically Ill PatientsCritical Care Clinics, Vol. 3, No. 1Errors in measurements of CO2 with the use of drying agentsClinica Chimica Acta, Vol. 158, No. 3Portable device for monitoring oxygen uptakeMedical & Biological Engineering & Computing, Vol. 24, No. 2An automated method for the measurement of oxygen consumption and carbon dioxide excretion in man14 February 2001 | Clinical Physics and Physiological Measurement, Vol. 6, No. 4Calculation of short-term changes in body fat from measurement of respiratory gas exchangeMetabolism, Vol. 33, No. 9Measurement of short-term changes in the fat content of the body: a comparison of three methods in patients receiving intravenous nutrition9 March 2007 | British Journal of Nutrition, Vol. 52, No. 2Indirect Calorimetry System for Assessment of Resting Energy Expenditure2 July 2016 | Journal of Parenteral and Enteral Nutrition, Vol. 8, No. 5Clinical Applications of Gas Exchange MeasurementsClinics in Anaesthesiology, Vol. 1, No. 3Effect of the Energy Source on Changes in Energy Expenditure and Respiratory Quotient During Total Parenteral Nutrition2 July 2016 | Journal of Parenteral and Enteral Nutrition, Vol. 7, No. 1The effect of gastrointestinal malignancy on resting metabolic expenditureBritish Journal of Surgery, Vol. 69, No. 8Effect of Added Insulin on Body Composition of Gastroenterologic Patients Receiving Intravenous Nutrition—a Controlled Clinical TrialGastroenterology, Vol. 81, No. 2An accurate method for the continuous measurement of oxygen consumption in infants during cardiac catheterizationCatheterization and Cardiovascular Diagnosis, Vol. 7, No. 3Physical training after heart valve replacement.Heart, Vol. 44, No. 6A modified open-circuit method for estimation of oxygen consumption and carbon dioxide excretion in adults, infants and small animalsPfl�gers Archiv European Journal of Physiology, Vol. 380, No. 2 More from this issue > Volume 37Issue 4October 1974Pages 604-7 https://doi.org/10.1152/jappl.1974.37.4.604PubMed4411666History Published online 1 October 1974 Published in print 1 October 1974 Metrics

An instrument for continuous measurement of oxygen consumption.

An instrument for continuous measurement of oxygen consumption.

Mechanisms of Oxidation of Ta‐10W Alloy Coated With Tungsten Disilicide

Continuous oxygen consumption measurements have been made on two commercially available W/Si type coatings, the TRW duplex coating and Solar's TNV‐13, at temperatures between 1000° and 1800°C and an oxygen partial pressure of 150 Torr in helium. The coatings were applied by the vendors to small cylindrical pellets of Ta‐10 a/o W. It was shown that the coated samples undergo significant changes in properties if preheated in nonoxidizing atmospheres. Although the as‐received TRW and TNV‐13 samples are both nominally similar, they exhibit totally different oxidation behavior under the conditions investigated. Oxidation of the TNV‐13 coated samples is parabolic between 1000° and 1700°C, and the parabolic rate constant increases with temperature. Oxidation of the TRW coated samples is logarithmic, and the extent of oxidation in a 1‐hr time period decreases as the temperature is increased from 1000° to 1250° to 1500°C. At 1700°C, the TNV‐13 coating provides protection, while the TRW coating fails catastrophically. The results of electron microprobe analysis suggest that the basic differences in oxidation mechanism between the two coating systems may be ascribed to the presence of a small amount of titanium in the TNV‐13 coating.

A volumetric respirometer for long-term studies of small aquatic animals

A modified volumetric respirometer was constructed for an extended series of precise determinations of the respiration of small aquatic animals. Food could be introduced and all operations could be carried out without disturbance to the animal. Provisions were made for the introduction of filtered, bacteria-free sea water between experimental runs. The advantages of the volumetric technique were combined with those of a running-water system to allow the continuous measurement of oxygen consumption under controlled conditions.

A method for the continuous measurement of oxygen consumption in the presence of inert gases during controlled ventilation.

SUMMARYA method is described which permits continuous determination of oxygen consumption during anaesthesia in the presence of inert gases. Owing to the diffusion characteristics of an inert gas as nitrous oxide, there are two conditions which must be fulfilled in order to measure the oxygen uptake:— A constant volume in the ventilatory system, which includes the patient's lungs, the anaesthesia machine and the measuring device. Constant partial pressures of gases in the system. These conditions are fulfilled when the Engström respirator in a closed system is connected to a volume‐controlling device which automatically adjusts the flow of metabolic oxygen into the system in such a way that the volume is kept constant. The oxygen is delivered from a hydrostatic spirometer of new design which permits a direct linear relationship between the change in hydrostatic pressure of the spirometer and the volume of delivered oxygen at atmospheric pressure. The oxygen is fed into the respirator system through a special slide valve, controlled by the changes in volume, and with a reciprocal action which keeps the volume constant. Constancy of partial pressures is maintained by adding the inert gas (nitrous oxide) through a precision rotameter into the system. Due to the reciprocal action of the oxygen slide valve a constant volume is ensured. A Beckman oxygen analyser is used as a zero instrument for the control of partial pressures.Model experiments with an artificial lung and a constant artificial oxygen consumption and gas mixtures of different composition have shown that the method has an error of 1.1 per cent. (S.D. ± 11.4 ml at a mean oxygen output from the spirometer of 1008 ml).Experiments on dogs with determination of the oxygen consumption by the method of Krogh utilising oxygen alone, and the method described in this paper when nitrous oxide was present, showed close agreement between the values for determined oxygen, which were all within the margins of error.Determinations during anaesthesia and surgical procedures have shown that the method is simple and permits accurate continuous monitoring of the oxygen uptake during various conditions.ZUSAMMENFASSUNGEs wird eine Methode beschrieben, die eine kontinuierliche Bestimmung des Sauerstoffverbrauches in Gegenwart inaktiver Gase während der Narkose gestattet. Infolge der Diffusionsbesonderheiten eines inaktiven Gases wie Stickoxydul, müssen zwei Bedingungen bei der Messung des Sauerstoffverbrauches erfüllt werden: Ein konstantes Volumen im Ventilationssystem, das die Lunge des Patienten, den Narkoseapparat und das Messgerät umfasst. Ein konstanter Partialdruck der Gase im System. Diese Bedingungen werden erfüllt, wenn der als geschlossenes System verwendete Engströmrespirator mit einer Volumenkontrollvorrichtung verbunden wird, die den Ersatz des im Stoffwechsel verbrauchten Sauerstoffes automatisch so regelt, dass das Volumen im System konstant gehalten wird. Der Sauerstoff wird von einem hydrostatischen Spirometer neuer Konstruktion geliefert, bei dem ein direktes lineares Verhaltnis zwischen der Änderung des hydrostatischen Druckes im Spirometer und dem Volumen des gelieferten Sauerstoffes bei atmosphärischem Druck besteht. Der Sauerstoff wird dem Respiratorsystem über ein besonderes Schieberventil zugeführt, das durch Volumsänderungen betätigt wird und so durch den gegensinnigen Ventilmechanismus das Volumen konstant hält. Der Partialdruck im System wird durch Zusetzen des inaktiven Gases (Stickoxydul) mit Hilfe eines Präzisionsrotameters konstant gehalten. Ein Beckman'scher Sauerstoffanalysator dient als Eichinstrument zur Kontrolle der Partialdrucke.Modellversuche mit einer künstlichen Lunge bei Verwendung von Gasgemischen verschiedener Zusammensetzung und einem konstanten künstlichen Sauerstoffverbrauch zeigten, dass die Methode eine Fehlerbreite von 1,1% hat. (Mittlere Abweichung: ± 11,4 ml. bei einem durchschnittlichen Sauerstoffzufluss aus dem Spirometer von 1008 ml.)Die Bestimmung des Sauerstoffverbrauches an Hunden mit der Krogh'schen Methode (mit Sauerstoff allein) und mit der in dieser Arbeit beschriebener Methode (Sauerstoff in Gegenwart von Stickoxydul) ergab weitgehend übereinstimmende Werte, die alle innerhalb der Fehlerbreite lagen. Bestimmungen wahrend Narkose und Operationen zeigten, dass die Methode einfach ist und eine genaue kontinuierliche Messung des Sauerstoffverbrauches unter verschiedenartigen Bedingungen erlaubt.