Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Consumption”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed2004

Diurnal rhythm and effect of temperature on oxygen consumption in earthworms, Amynthas gracilis and Pontoscolex corethrurus.

Different species of earthworms show distinct patterns of oxygen consumption pattern. Amynthas gracilis has a diurnal rhythm of oxygen consumption, consuming more oxygen at night, whether being incubated at 20, 25, or 30 degrees C. The higher oxygen consumption of A. gracilis is directly related to its behavior, as it shows higher activity at night. In contrast, Pontoscolex corethrurus showed no obvious diurnal rhythms of oxygen consumption or behavior. In addition, its oxygen demand is not related to temperature. A. gracilis has higher oxygen consumption than P. corethrurus at 20 and 30 degrees C. The difference in temperature adaptation of oxygen consumption between these two species may be a strategy by which earthworms adapt to different temperatures. This might explain why A. gracilis disperses on the soil surface at night after a rain, in contrast to P. corethrurus for which such behavior was not been observed.

Analysis of Variance↗
PubMed1997

Oxygen consumption of calvarial bone cells in vitro.

Tissues with tortuous and narrow diffusion pathways and cells that are remote from blood vessels nonetheless can show high metabolic activity of which the underlying bases (transport mechanisms) are not fully understood. In one such bone tissue, the O2 consumption was measured by analyzing the decrease in the partial pressure of oxygen (Po2) in a closed chamber containing calvarial fragments from adult guinea pigs (250-400 g) or from neonatal rats and guinea pigs. The O2 consumption of fragments from adult guinea pigs amounted to 0.05, 0.066, and 0.095 ml/100 g* minute at 24, 27, and 36.5 degrees C, respectively. When the temperature exceeded 43 degrees C, O2 consumption irreversibly stopped. Both antimycin A and rotenone, which block the respiratory chain, reduced O2 consumption to approximately 20% of control values. O2 consumption was significantly higher in neonatal animals (0.369 ml/100 g* minute at 27 degrees C) and could be blocked completely by antimycin A. On the basis of the high consumption of O2 by bone cells, we hypothesize that specialized transport systems, i.e., gap junctions, are required to provide a sufficient supply of nutrients to cells in osseous tissue.

Age Factors↗
PubMed2002

Non-respiratory oxygen consumption pathways in anaerobically-grown Saccharomyces cerevisiae: evidence and partial characterization.

Despite the absence of an alternative mitochondrial ubiquinol oxidase, Saccharomyces cerevisiae consumes oxygen in an antimycin A- and cyanide-resistant manner. Cyanide-resistant respiration is typically used when the classical respiratory chain is impaired or absent (i.e in anaerobically-grown cells shifted to normoxia or in respiratory-deficient cells). We characterized the non-respiratory oxygen consumption pathways operating during anoxic-normoxic transitions in glucose-repressed resting cells. High-resolution oxygraphy confirmed that the cellular non-respiratory oxygen consumption pathway is sensitive to high concentrations of cyanide, azide, SHAM and TTFA, and revealed several new characteristics. First, the use of sterol biosynthesis inhibitors showed that this pathway makes a considerable contribution (about 25%) to both endogenous and glucose-dependent oxygen consumption. Anaerobically-grown glucose-repressed cells exhibited high apparent oxygen affinities (K(m) for oxygen = 0.5-1 micro M), even in mutants deficient in respiration or sterol synthesis. Exogeneously added glucose and endogenous stored carbohydrates were the only substrates that were efficient for cellular oxygen consumption (apparent K(m) for exogenous glucose = 2-3 mM). On the other hand, fluorimetric measurements of the cellular NAD(P)H pool showed that the cellular oxygen consumption (sterol biosynthesis and unknown pathways) was dependent more on the intracellular level of NADPH than of NADH. High oxygen affinity NADPH-dependent oxygen consumption systems were thought to be mainly localized in microsomal membranes, and several data indicated a significant contribution made by uncoupled p450 systems, together with still uncharacterized systems. Such activities are associated in vitro with a massive production of O(2) (.-) and, to a lower extent, H(2)O(2) and a likely concomitant production of H(2)O.

Anaerobiosis↗
PubMed2000

Impaired nitric oxide modulation of myocardial oxygen consumption in genetically cardiomyopathic hamsters.

We investigated the role of kinin and nitric oxide (NO) in the modulation of cardiac O(2)consumption in Syrian hamsters with overt heart failure (HF) and age-matched normal hamsters. Using echocardiography, the hamsters with heart failure had reduced ejection fraction [31(+/-8) v 76(+/-5)%] and LV dilation [4.9(+/-0. 2) v 5.7(+/-0.3) mm, both P<0.05 from normal]. O(2)consumption in the left ventricular free wall was measured using a Clark-type O(2)electrode in an air-tight chamber, containing Krebs solution buffered with Hepes (37 degrees C, pH 7.4). Concentration response curves to bradykinin (BK), ramiprilat (RAM), amlodipine (AMLO) and the NO donor, S -nitroso- N -acetyl-penicillamine (SNAP) were performed. Basal myocardial O(2)consumption was lower in the HF group compared to normal [316(+/-21) v 404(+/-36) nmol O(2)/min/g, respectively, P<0.05]. In the hearts from normal hamsters BK (10(-4)mol/l), RAM (10(-4)mol/l), and AMLO (10(-5)mol/l) all significantly reduced myocardial O(2)consumption by 42(+/-6)%, 29(+/-7)% and 27(+/-5)% respectively. This reduction was attenuated in the presence of N -nitro- l -arginine methyl ester (l -NAME) [BK: 3.3(+/-1.5)%, RAM: 3.3(+/-1.2)%, AMLO: 2.3(+/-1.2)%, P<0.05]. Interestingly in the hearts from HF group, BK, RAM and AMLO caused a significantly smaller reduction in myocardial O(2)consumption [10(+/-2)%, 2.5(+/-1.3)%, 6.3(+/-2.3)%, P<0.05]. In contrast, the NO donor SNAP reduced myocardial O(2)consumption in both groups and all those responses were not affected by l -NAME. These data indicate that endogenous NO production through the kinin-dependent mechanism is impaired at end-stage heart failure. The loss of kinin and NO control of mitochondrial respiration may contribute to the pathogenesis of heart failure.

Amlodipine↗
PubMed1994

Investigation of the human oxygen transport system during conditions of rest and increased oxygen consumption by means of fractionation. Effects of oxygen isotopes.

The aim of the study was to assess various pathways of the oxygen transport system at rest and ergometer work by the utility of information derivable from different behaviour of the isotopic oxygen molecules 16O2 and 16O18O during transport. 6 healthy humans were studied at rest and at different levels of ergometer work, ranging from 50 to 250 W. Isotope analysis was performed by applying a reference technique. Samples of inspiratory and expiratory gas, taken during steady state conditions, were analysed by a respiratory mass spectrometer on their 16O18O/16O2 ratios by comparing them with a reference gas of appropriate composition. Ventilatory minute volume, oxygen consumption and end-expiratory oxygen partial pressure were also measured. At rest, the delta IU-value quantifying the isotope effect of the overall oxygen transport amounted to 0.74 +/- 0.08%. During ergometer work, the fractionation factor steadily decreased with increasing oxygen consumption, yielding the regression line delta IU [%] = 0.74 -1.3.10(-4).VO2, where VO2 is oxygen consumption given in ml/min. With respect to oxygen transport from inspiratory gas to tissue, this result suggests: convective processes of oxygen transport become more limiting with increasing oxygen consumption, whereas diffusion does not become a major limiting step up to oxygen consumption rates of 3600 ml/min, otherwise a reverse relationship between fractionation factor and oxygen consumption should have been found.

Biological Transport, Active↗
PubMed1978

[Oxygen consumption of the spontaneous and artificially induced skincycle at different times of day (author's transl)].

In the "clean" rat skin purified from the panniculus carnosus the oxygen consumption of the spontaneous and artificially induced skincycle was measured at different times of day. The level of oxygen consumption correlated to diurnal and nocturnal periods. During the skincycle the oxygen consumption showed fluctuations. There were indications that the value of oxygen consumption of the early anagen is influenced by that phase of the cycle at which the new cycle is artificially induced. Furthermore, it was found that a certain decrease of oxygen consumption stimulates the quiescent hair follicles to spontaneous proliferation. During the katagen the peak value of the oxygen consumption seemed to be correlated with specially morphofunctional perifollicular changes. The application of these findings to the pathophysiology of human hair growth disturbances is discussed.

Animals↗
PubMed1977

Direct determination of local oxygen consumption of the brain cortex in vivo.

A method is described to determine local oxygen consumption quantitatively in the brain cortex under in vivo conditions. Local oxygen consumption is calculated from the slope of local tissue PO2 decrease during a few seconds of total ischemia of the brain for each second after the stop of circulation. The decrease of tissue PO2 is recorded simultaneously at several measuring sites. To be independent of oxygen chemically bound to hemoglobin, tissue PO2 values are raised above 100 Torr. The calculation of local oxygen consumption for each second during the short period of ischemia showed that the O2 consumption remains constant only for a few seconds ranging from 5 to maximally 15 s at different locations. The O2 consumption decreases continuously although the tissue PO2 values are still above the full saturation of hemoglobin. The rate of local oxygen consumption varies considerably at different measuring sites of the superficial layers of the brain cortex (cat). The mean value amounts to 3 +/- 1.5 ml O2/100 g tissue and minute.

Animals↗
PubMed1986

Effect of short-term energy intake level and exercise on oxygen consumption in men.

The influence of short-term energy intake and cycle exercise on oxygen consumption in response to a 1.5 MJ test meal was investigated in ten young, adult men. On the morning after a previous day's "low-energy" intake (LE regimen) of 4.5 MJ, the mean resting oxygen consumption increased by 0.7 ml X kg-1 X min-1 after the test meal (P less than 0.025). After a "high-energy" intake (HE regimen) of 18.1 MJ, the resting measurement was unchanged (+0.4 ml X kg-1 X min-1) after the meal (n.s.). These trends are the reverse of what would be expected if oxygen consumption in response to feeding is a factor in the acute control of body weight. The mean fasting oxygen consumption during cycle exercise at 56% of VO2max (constant work) for both LE and HE prior intakes was not different at 31.1 ml X kg-1 X min-1. Oxygen consumption during exercise increased after feeding by 0.5 ml X kg-1 X min-1 on the LE regimen (n.s.) and decreased by 1.2 ml X kg-1 X min-1 on the HE regimen (n.s.). These results are also the reverse of what would be expected if oxygen consumption in response to exercise is related to short-term energy intake.

Body Weight↗
PubMed1992

Oxygen consumption and mixed venous oxygen saturation monitoring during orthotopic liver transplantation.

Mixed venous oxygen saturation (SvO2) monitoring has been advocated for some critically ill patients. Patients with end-stage hepatic failure have oxygen consumption rates that are lower than normal. Using the Fick equation, oxygen consumption may be calculated if mixed venous and arterial oxygen tensions (and saturations), hemoglobin, and cardiac output are determined simultaneously. This report describes a unique pattern of changes in SvO2 and oxygen consumption in 7 patients undergoing liver transplantation. A previous study correlated plasma carbohydrate (glucose) levels with early hepatic graft survival. After induction, the 7 patients reported here had low oxygen consumption and high SvO2 values. The oxygen consumption rates decreased to the lowest point during the anhepatic phase and rose above baseline by the end of the case. The SvO2 and oxygen consumption data reported here follow the presence of presumed hepatic metabolic activity (increased CO2 and ionized calcium). Further research must be completed to determine whether these measurements indicate early hepatic nonfunction.

Adult↗
PubMedDate not supplied

Experimental hyperthyroidism IV. Myocardial muscle mechanics and oxygen consumption in euand hyperthyroidism.

Myocardial mechanics and oxygen consumption were studied in right ventricular papillary muscles taken from cats pretreated with cristalline L-thyroxine (1 mg/kg/day, i.p.) 8-18 days prior to the examination. Isotonic afterloaded and isometric contractions were employed. Oxygen consumption was determined polarographically. Data obtained were compared with control studies on papillary muscles taken from euthyroid cats. In isotonic afterloaded contractions the extent of shortening was nearly identical in both groups. However, maximum rate of isometric tension development and velocity of isotonic shortening were considerably increased in hyperthyroid myocardium. Myocardial oxygen consumption was significantly increased in hyperthyroidism, primarily due to an increased maximum rate of isometric tension development and-to a lesser extent-to increased isotonic contraction velocity. In isometric contractions maximum tension development (preload near Lmax) was similar in both groups. However, maximum rate of isometric tension development was markedly increased in hyperthyroidism. A close and linear relationship was found between maximum rate of isometric tension development (isometric contraction) and myocardial oxygen consumption. The results demonstrate increases of velocity factors of myocardial performance in experimental hyperthyroidism. Myocardial oxygen consumption is significantly increased. This increase in oxygen consumption quantitatively has its mechanical equivalent in increased isometric contraction velocity and, to a small amount, in increased isotonic contraction velocity.

Animals↗
PubMed2001

Acetyl-L-carnitine treatment stimulates oxygen consumption and biosynthetic function in perfused liver of young and old rats.

The effect of treatment with acetyl-L-carnitine on hepatic mitochondrial respiration and biosynthetic function in perfused liver from young (90 days) and old (22-24 months) rats was studied. Rats were given a 1.5% (w/v) solution of acetyl-L-carnitine in their drinking water for 1 month and oxygen consumption together with the rate of gluconeogenesis, urea synthesis, and ketogenesis with and without added substrates were measured in perfused liver. Mitochondrial oxygen consumption was also assessed in liver homogenate and isolated mitochondria to determine the maximal capacity for oxidative phosphorylation. Acetyl-L-carnitine treatment almost completely restored the age-dependent decline in oxygen consumption, gluconeogenesis, urea synthesis, and ketogenesis found in perfused liver of old rats to the levels found in young rats. In addition, acetyl-L-carnitine treatment increased oxygen consumption and biosynthetic function in perfused liver from young rats. After acetyl-L-carnitine treatment, we found detectable 3-oxoacyl-CoA-transferase activity associated with a consumption of ketone bodies in young and old rats. Finally, oxygen consumption measured in homogenate and isolated mitochondria did not change with age and acetyl-L-carnitine treatment. Our results show that in perfused liver, acetyl-L-carnitine treatment slows the age-associated decline in mitochondrial respiration and biosynthetic function. In addition, treatment of young rats with acetyl-L-carnitine has a stimulating effect on liver metabolism, probably through an increase in ATP production.

Acetyl-CoA C-Acyltransferase↗
PubMed2004

Light dependence of oxygen consumption by blowfly eyes recorded with a magnetic diver balance.

We measured the oxygen (O2) consumption of isolated blowfly eyes using a magnetic diver balance, a device for high-resolution volumetric O2 consumption measurements. The light-induced O2 consumption is at most three times the value of the dark consumption, which is 0.6 nl O2 s(-1) eye(-1), and is in good agreement with the estimates based on electrophysiological data. With longer stimuli the increase follows a double exponential time course. The respective time constants are approximately 2 and 20 s and show no dependence on light intensity, whereas the dependence of amplitudes can be fitted by a Hill equation. Decreasing the stimulus duration reveals that the peak in O2 consumption overshoots the time course induced by long stimuli. We suggest this may be a general feature of mitochondrial activation. The dependence of the O2 consumption peak on stimulus duration at high light intensity has a hump with stimulus durations of 10-20 ms, coinciding with the stimulus durations that start to induce the adaptation of the receptor potential.

Algorithms↗
PubMed2000

Cyclic GMP attenuates cyclic AMP-stimulated inotropy and oxygen consumption in control and hypertrophic hearts.

We tested the hypothesis that increasing myocardial cyclic GMP would attenuate cyclic AMP induced positive inotropy and O2 consumption, in part, through changes in cyclic AMP and that renal hypertension-induced cardiac hypertrophy (HYP) would alter this relationship. Anesthetized, open chest rabbits (N = 48) were divided into four groups of control (CON) and HYP animals which received vehicle (VEH), isoproterenol 10(-6)M (ISO), 3-morpholinosyndnonimine 10(-4)M, (SIN-1), or a combination of ISO+SIN-1. Coronary blood flow (microspheres) and O2 extraction (microspectrophotometry) were used to determine O2 consumption in both subepicardium (EPI) and subendocardium (ENDO). Left ventricular change in wall thickness (%) was increased significantly by ISO in both CON (16 +/- 4 to 31 +/- 6) and HYP (17 +/- 2 to 24 +/- 3). Percent change in wall thickness was similar in the CON, SIN-1, and ISO+SIN-1 groups. Myocardial O2 consumption (ml O2/min/100 g) was increased by ISO in CON (10.3 +/- 1.0 to 13.6 +/- 2.0 EPI; 10.9 +/- 1.0 17.1 +/- 1.7 ENDO) and HYP (8.2 +/- 1.4 to 12.3 +/- 2.2 EPI; 6.6 +/- 1.4 to 14.8 +/- 1.8 ENDO). Oxygen consumption was unaffected by SIN-1 in CON and HYP animals. ISO+SIN-1 caused attenuated ISO-induced increases in O2 consumption in CON in EPI and ENDO, and in EPI in HYP. Cyclic GMP (pmol/g) was unchanged by ISO in CON and HYP, and increased by SIN-1 in CON (8.1 +/- 1.3 to 19.2 +/- 2.3 EPI) and HYP (9.1 +/- 1.5 to 12.8 +/- 2.0 EPI). Cyclic GMP remained elevated with ISO+SIN-1 in both groups. Cyclic AMP (pmol/g) was increased significantly by ISO in CON (496 +/- 43 to 725 +/- 106 EPI; 534 +/- 44 to 756 +/- 148 ENDO) and insignificantly in HYP (435 +/- 50 to 566 +/- 35 EPI; 497 +/- 51 to 583 +/- 47 ENDO). Cyclic AMP levels were unaffected by SIN-1 in either group. Isoproterenol induced increases in cyclic AMP were blunted by ISO+SIN-1 in CON (496 +/- 43 to 537 +/- 59 EPI) and not affected in HYP. The current study demonstrated attenuation of cyclic AMP mediated increased inotropy and O2 consumption by increasing cyclic GMP, which appeared, in part, related to cyclic GMP-induced reduction in cyclic AMP. This effect of cyclic GMP on cyclic AMP was not observed in myocardial hypertrophy.

Animals↗
PubMed2004

Differences between cytotoxicity in photodynamic therapy using a pulsed laser and a continuous wave laser: study of oxygen consumption and photobleaching.

Oxygen consumption at the targeted site has a significant effect on dosimetry in photodynamic therapy (PDT). However, oxygen consumption in PDT using a pulsed laser as a light source has not been clarified. We therefore investigated the dependence of cytotoxicity on the oxygen consumption and the photosensitizer photobleaching of PDT using a pulsed laser by comparing with that using a continuous wave (CW) laser. Mouse renal carcinoma cells (Renca) were incubated with a second-generation photosensitizer, PAD-S31. The cells were then irradiated with either a 670-nm nanosecond pulsed light from the 3rd harmonics of a Nd:YAG laser-pumped optical parametric oscillator with a peak fluence rate of approximately 1 MW/cm(2) at 30 Hz or a 670-nm CW diode laser with a total light dose of 40 J/cm(2). Regardless of laser source, cytotoxic effects exhibited cumulative dose responses to the photosensitizer ranging from 12 to 96 microg/ml. However, cytotoxic effect of PDT using the pulsed light was significantly less than that using the CW light with the photosensitizer concentrations of 24 and 48 microg/ml under identical fluence rates. During PDT, the cells exposed to the pulsed light consumed oxygen more slowly, resulting in a lower amount of oxygen consumption when compared with PDT using CW light. In accordance with oxygen consumption, the pulsed light induced significantly less photobleaching of the photosensitizer than the CW light did. These results indicate that the efficiency of PDT using pulsed light is less when compared with CW light, probably being related to suppressed oxygen consumption during the pulsed light irradiation.

Animals↗
PubMed2006

Oxygen consumption and respiration during and after two yoga relaxation techniques.

Cyclic meditation (CM) is a technique which combines "stimulating" and "calming" practices, based on a statement in ancient yoga texts suggesting that such a combination may be especially helpful to reach a state of mental equilibrium. The oxygen consumption, breath rate and breath volume of 50 male volunteers (group mean age+/-SD, 27+/-6.3 years) were assessed before, during, and after sessions of CM and sessions of supine rest in the corpse posture (shavasana, SH). The sessions were one day apart and the order was alternated. The oxygen consumption, breath rate and breath volume increased during the "stimulating" practices of CM, returned to the baseline during the "calming" practices, and the oxygen consumption decreased by 19.3 percent below baseline values after CM. During the SH session the oxygen consumption, breath rate and breath volume reduced; however the decrease in oxygen consumption after SH was less than after CM (i.e., 4.8 percent). The results support the idea that a combination of yoga postures with supine rest (in CM) reduces the oxygen consumption more than resting supine alone does.

Adolescent↗
PubMed1984

Effect of morphine on regional cerebral oxygen consumption and supply.

The effects of acute opiate receptor stimulation on regional cerebral oxygen consumption and blood flow were examined in 9 regions of the artificially respired, alpha-chloralose-anesthetized cat. Regional cerebral arterial and venous oxygen saturation were examined microspectrophotometrically and regional cerebral blood flow was monitored using radioactively tagged microspheres (15 +/- 3 micron in diameter). Oxygen consumption was calculated as the product of flow and oxygen extraction. In 8 cats, after control cerebral blood flow was obtained, and in 8 experimental cats after this same measurement was obtained before and 40 min after the administration of 1.5 mg/kg morphine sulfate; the cats' heads were simultaneously sawed in 3 places and quickly frozen in liquid nitrogen-cooled propane. Systolic and diastolic blood pressure were significantly decreased by treatment. The heterogeneity of venous oxygen saturation was significantly reduced by morphine. Average cerebral blood flow, oxygen extraction and consumption were not altered significantly by morphine. Regional cerebral blood flow in the hypothalamus, thalamic oxygen extraction, and hypothalamic and thalamic oxygen consumption were significantly decreased by treatment. This low dose of morphine may produce changes in cerebral neuronal and/or synthetic activity which lowers oxygen consumption in some regions rich in opiate receptors, while not affecting overall brain oxygen supply or consumption.

Animals↗
PubMed1988

Effects of excitatory amino acids on the oxygen consumption of hippocampal slices from the guinea pig.

The effects of excitatory amino acids such as glutamate (Glu) and aspartate (Asp), and their receptor agonists, kainate (Ka), N-methyl-D-aspartate (NMDA), and quisqualate (Quis) on the neuronal activity and the oxygen consumption were investigated using hippocampal slices of the guinea pig. Bath application of these excitants elevated the amplitude of the postsynaptic field potential (PSP) to approximately 120% of the original level at low concentrations, although effective doses varied for the different excitants (Ka greater than NMDA greater than Quis greater than Glu greater than Asp). At concentrations over each effective dose the PSP was diminished and subsequently abolished. The application of Ka (1 x 10(-8) to 1 x 10(-6) M), NMDA (1 x 10(-8) to 1 x 10(-4) M), Quis (1 x 10(-7) to 1 x 10(-4) M), Glu (1 x 10(-5) to 5 x 10(-4) M), and Asp (1 x 10(-5) to 5 x 10(-3) M) enhanced the oxygen consumption dose-dependently, to a maximum of 120-146% of the resting level (8.43 mumol/g protein/min). It was notable that the initial increase in the oxygen consumption was associated with neuronal excitation and the doses of the excitants producing maximal oxygen consumption was in good agreement with those demonstrating disappearance of the PSP, probably because of massive depolarization of the neurones. The increase of the oxygen consumption and the neuronal activity induced by the excitants were specifically inhibited by their antagonists, such as glutamic acid diethylester (GDEE), DL-2-amino-5-phosphonovaleric acid (APV), and Joro spider toxin (JSTX). The present results strongly suggest that the enhancement of oxygen consumption due to the excitatory amino acids and agonists must reflect the neuronal activation induced by them.

2-Amino-5-phosphonovalerate↗
PubMed1989

Independent measurement of oxygen consumption and oxygen delivery.

This experiment investigated the relationship between oxygen consumption and oxygen delivery (cardiac output X arterial oxygen content) in an acute canine model. Previous studies investigating this relationship have largely utilized methods in which oxygen consumption and oxygen delivery were each calculated using the same measured variables resulting in mathematical coupling of variables. In this study, oxygen consumption was measured directly by closed-circuit spirometry. Oxygen delivery was independently controlled using right atrial bypass. These techniques assured that the values for oxygen consumption and oxygen delivery were derived entirely independently. In our study using 11 dogs, we found that oxygen consumption was constant and independent of oxygen delivery at oxygen delivery levels greater than 8.0 cc/kg/min (normal canine oxygen delivery 20-25 cc/kg/min). Oxygen consumption was linearly related to oxygen delivery at oxygen delivery levels less than or equal to 8.0 cc/kg/min. Below this critical level of oxygen delivery, animals were more acidotic and hypotensive than at higher delivery levels.

Animals↗