Www.research.ed.ac.uk



AbstractObjectiveTo determine agreement in oxygen consumption (VO2) values calculated using Sykes’ formula VO2 = (FIO2 – Fe′O2 ) X V?E (where FI and FE are the inspired and end-tidal fractional concentrations of O2 respectively and VM = minute volume; ADDIN EN.CITE <EndNote><Cite><Author>Sykes</Author><Year>2010</Year><IDText>Oxygen monitoring during low flow anaesthesia</IDText><DisplayText>(Sykes, 2010)</DisplayText><record><dates><pub-dates><date>2010//</date></pub-dates><year>2010</year></dates><urls><related-urls><url> monitoring during low flow anaesthesia</title><secondary-title>Journal of Clinical Monitoring and Computing</secondary-title></titles><pages>141-141</pages><number>2</number><contributors><authors><author>Sykes, Oliver</author></authors></contributors><added-date format="utc">1489502591</added-date><ref-type name="Journal Article">17</ref-type><rec-number>185</rec-number><last-updated-date format="utc">1489502591</last-updated-date><electronic-resource-num>10.1007/s10877-010-9222-8</electronic-resource-num><volume>24</volume></record></Cite></EndNote>(Sykes, 2010)) with values derived using Brody’s formula (VO2 = 10kg3/4; ADDIN EN.CITE <EndNote><Cite><Author>Brody</Author><Year>1945</Year><IDText>Bioenergetics and growth: with special reference to the efficiency complex in domestic animals</IDText><DisplayText>(Brody, 1945)</DisplayText><record><titles><title>Bioenergetics and growth: with special reference to the efficiency complex in domestic animals</title><secondary-title>Bioenergetics and growth: with special reference to the efficiency complex in domestic animals.</secondary-title></titles><contributors><authors><author>Brody, Samuel</author></authors></contributors><added-date format="utc">1489502686</added-date><ref-type name="Journal Article">17</ref-type><dates><year>1945</year></dates><rec-number>186</rec-number><publisher>New York: Reinhold Publishing Corporation</publisher><last-updated-date format="utc">1489502686</last-updated-date></record></Cite></EndNote>(Brody, 1945)). It was hypothesized that the two methods would not yield statistically significant differences in calculated values.Study DesignProspective, clinical, pilot study.AnimalsTwenty-two client-owned dogs.MethodsThe minute volume of ventilation (Vm), FIO2 and Fe′O2 were measured during positive pressure ventilation of the lungs (Vt: 10 mL kg-1; fr: 8–12 breaths minute-1) in dogs undergoing surgery anaesthetized with either isoflurane or sevoflurane. Oesophageal temperature was maintained between 37.0 and 38.5 ?C. Values for VO2 derived by Sykes’ and Brody’s methods were compared and agreement determined using Bland-Altman analysis.ResultsMean VO2, calculated using Brody’s formula, was 4.67 (±0.51) mL kg -1 min-1 whilst the mean value using Sykes’ equation was 5.32 (±1.69) mL kg -1 min-1. There was greater variability in the values obtained from Sykes’ equation. The Bland-Altman plot revealed a proportional error with correlation but poor agreement between values. Conclusion and clinical relevanceBoth methods yielded VO2 values of approximately 5 mL kg-1min-1 with no statistically significant differences between the two methods. IntroductionOxygen consumption (VO2) - the volume of O2 used per unit time - depends on factors including basal metabolic rate, body temperature, body composition, gender and age. When oxygen delivery per unit time (DO2) falls below VO2, anaerobiosis occurs. Brody (1945) proposed oxygen consumption (VO2) in conscious homeotherms could be estimated by the equation: VO2 = 10 BW (body weight)3/4 mL minute-1. Whilst VO2 is normally reduced during anaesthesia, anaesthetics may reduce DO2 in a disproportionally greater manner, especially when factors limiting DO2 are present, or VO2 is elevated, e.g. in pregnancy, during surgical stimulation, hyperthyroidism, and malignant hyperthermia. For any values of VO2, O2 delivery into breathing systems must ensure that the inspired gas composition does not become a factor limiting DO2. This can be assured by measuring – and increasing when necessary - the fractional concentration of inspired O2 (FiO2).Based as it is on body mass alone, Brody’s law is unlikely to provide adequately accurate estimates of VO2 in anaesthetized, sick subjects. In these, application of the Fick principle is more appropriate, i.e.VO2 = Qt X C(a-v)O2wWhere Qt = cardiac output, and C(a-v)O2 is the arteriovenous O2 content difference.However, Fick’s method requires pulmonary arterial catheterisation so may be unjustifiably invasive and costly. An alternative method involves measuring VO2 under anaesthesia using the formula:VO2 = (FIO2 - Fe/O2) X V?E. (Sykes, 2010) where VO2 = oxygen consumption, FIO2 = fraction of inspired oxygen, Fe/O2 = end tidal fraction of oxygen and V?E = minute volume.This method is non-invasive, achievable using widely available technology and enables the frequent adjustment of oxygen flows by a simple calculation in real time. The objective of this study was to compare the values for VO2 in anaesthetized dogs calculated using Sykes’ formula with those derived using Brody’s equation. The null hypothesis was that the two methods would not yield statistically significant differences in calculated values.Material and MaterialsThe study received ethical approval from the veterinary ethical review committee of the XXXXX. Dogs of either gender, and all ages and habitus, scoring 1, 2 or 3 on the American Society of Anaesthesiologists physical status scale ADDIN EN.CITE <EndNote><Cite><Author>New Classification of Physical</Author><Year>1963</Year><IDText>American Society of Anaesthesiologists</IDText><DisplayText>(New Classification of Physical, 1963)</DisplayText><record><titles><title>American Society of Anaesthesiologists</title><secondary-title>Anaesthesiology</secondary-title></titles><contributors><authors><author>New Classification of Physical, status</author></authors></contributors><added-date format="utc">1537195240</added-date><ref-type name="Journal Article">17</ref-type><dates><year>1963</year></dates><rec-number>296</rec-number><last-updated-date format="utc">1537195240</last-updated-date><volume>24</volume></record></Cite></EndNote>(New Classification of Physical, 1963) and admitted to the XXXX hospital to undergo orthopaedic and soft tissue surgery under general anaesthesia were studied. In all cases the animals’ body mass was measured using a Marsden V-150 veterinary scale (Marsden, Rotherham, UK) no more than 12 hours before anaesthesia. Body condition score was recorded ADDIN EN.CITE <EndNote><Cite><Author>Laflamme</Author><Year>1997</Year><IDText>Development and validation of a body condition score system for dogs</IDText><DisplayText>(Laflamme, 1997)</DisplayText><record><dates><pub-dates><date>1997</date></pub-dates><year>1997</year></dates><urls><related-urls><url> and validation of a body condition score system for dogs</title><secondary-title>Canine Pract.</secondary-title></titles><pages>10-15</pages><contributors><authors><author>Laflamme, D.</author></authors></contributors><added-date format="utc">1510828941</added-date><ref-type name="Journal Article">17</ref-type><rec-number>258</rec-number><last-updated-date format="utc">1510828941</last-updated-date><volume>22</volume></record></Cite></EndNote>(Laflamme, 1997). Pre-anaesthetic medication and induction agents were selected by individual anaesthetists based on animal and operative requirements. However, in all cases, the trachea was intubated, the lungs were ventilated, and anaesthesia was maintained with either isoflurane or sevoflurane delivered in oxygen. Physiological monitoring consisted of capnography, electrocardiography, non-invasive arterial blood pressure, oesophageal temperature and pulse oximetry. The lungs of all animals were mechanically ventilated using a Datex Smartvent (Ohmeda 7900,?Datex-Ohmeda, GE Healthcare, UK) and V?E, FIO2 and Fe/O2 were recorded using a Datex S5 monitor and pitot tube spirometry. The same anaesthetic machine and monitor wereas used for all animals. Initially, a tidal volume of 10 mL kg -1 was delivered at an fR of 12 breaths per minute. The fR was adjusted to maintain end-tidal CO2 (Fe/CO2) values of 5.2 - 5.4 kPa (39 - 42 mm Hg). Oesophageal body temperature was measured using a Datex S5 K-type thermistor and maintained between 37.0 and 38.5?C using blankets, bubble wrap, minimal clipping and a 3M Bair Hugger. Baseline values for V?E, FiO2 and Fe/O2 were recorded once a surgical plane of anaesthesia had been achieved (as indicated by ocular position, palpebral areflexia and other signs of cranial nerve inactivity including jaw tone) but before surgery began. Values for VO2 using Sykes’ formula were compared with values using Brody’s formula. Consequently 22 pairs of VO2 values were obtained. Statistical AnalysisOxygen consumption data are shown as mean and standard deviation (± SD). Using MedCalc () a Bland & Altman plot (1986) was used to assess agreement between VO2 from Sykes’ formula and Brody’s formula (Figure 1). The difference in VO2 was calculated using (Sykes’ – Brody). Limits of agreement and bias are plotted on the graph. The plot was examined for evidence of bias or proportional error. In case of proportional error a regression line was drawn. Statistical significance was set at p < 0.05. Results A total of 22 dogs were studied. Body weight and ASA classification values are detailed in Table 1. Median body weight was 23.2 kg (range of 7.2 to 40 kg). Most dogs (15/22) were scored as body condition score 2-6. Mean VO2, calculated using Brody’s formula, was 4.67 (±0.51) mL kg -1 minute-1 whilst the mean measured value using Sykes’ formula was 5.32 (±1.69) mL kg -1 minute-1. There was no statistically significant difference between the values for oxygen consumption usding the different formulae. A Bland and Altman plot (Figure 1) revealed a bias of 0.6518 and limits of agreement were -2.487 and 3.79. There was a proportional error with correlation but poor agreement between values. The regression line did not demonstrate statistical significance. The plot showed decreased agreement at higher values of oxygen consumption. DiscussionThe measured mean value for VO2 using Sykes' formula was not significantly different from that using Brody’s formula which was unexpectedexpected and therefore supported our hypothesis.: The limits of agreement for the formulae were wide and as values of oxygen consumption increased the difference between the two methods became greater. The wide limits of agreement are unacceptable in a clinical context and this demonstrates that the two methods are not interchangeable. Brody’s formula was based on values obtained in conscious animals, while isoflurane anaesthesia causes a 15% reduction in metabolic rate - and, therefore, VO2 ADDIN EN.CITE <EndNote><Cite><Author>Rolly</Author><Year>1984</Year><IDText>Cardiovascular, metabolic and hormonal changes during isoflurane N2O anaesthesia</IDText><DisplayText>(Rolly et al., 1984)</DisplayText><record><dates><pub-dates><date>Dec</date></pub-dates><year>1984</year></dates><keywords><keyword>Adult</keyword><keyword>*Anesthesia, Inhalation</keyword><keyword>Blood Glucose/metabolism</keyword><keyword>Blood Pressure/drug effects</keyword><keyword>Carbon Dioxide/blood</keyword><keyword>Cardiac Output/drug effects</keyword><keyword>Epinephrine/blood</keyword><keyword>Female</keyword><keyword>Heart Rate/drug effects</keyword><keyword>Hemodynamics/*drug effects</keyword><keyword>Hormones/*blood</keyword><keyword>Humans</keyword><keyword>Hydrocortisone/blood</keyword><keyword>Hysterectomy</keyword><keyword>Isoflurane/*pharmacology</keyword><keyword>Methyl Ethers/*pharmacology</keyword><keyword>Middle Aged</keyword><keyword>Nitrous Oxide</keyword><keyword>Norepinephrine/blood</keyword><keyword>Oxygen/blood</keyword><keyword>Oxygen Consumption/*drug effects</keyword><keyword>Prolactin/blood</keyword><keyword>Stroke Volume/drug effects</keyword></keywords><isbn>0265-0215 (Print)&#xD;0265-0215</isbn><titles><title>Cardiovascular, metabolic and hormonal changes during isoflurane N2O anaesthesia</title><secondary-title>Eur J Anaesthesiol</secondary-title><alt-title>European journal of anaesthesiology</alt-title></titles><pages>327-34</pages><number>4</number><contributors><authors><author>Rolly, G.</author><author>Versichelen, L.</author><author>Moerman, E.</author></authors></contributors><edition>1984/12/01</edition><language>eng</language><added-date format="utc">1510080844</added-date><ref-type name="Journal Article">17</ref-type><remote-database-provider>NLM</remote-database-provider><rec-number>251</rec-number><last-updated-date format="utc">1510080844</last-updated-date><accession-num>6443092</accession-num><volume>1</volume></record></Cite></EndNote>(Rolly et al., 1984). Furthermore, mechanical ventilation reduces oxygen requirements beyond the reductions caused by anaesthesia ADDIN EN.CITE <EndNote><Cite><Author>Aubier</Author><Year>1982</Year><IDText>Respiratory muscle contribution to lactic acidosis in low cardiac output</IDText><DisplayText>(Aubier et al., 1982)</DisplayText><record><dates><pub-dates><date>Oct</date></pub-dates><year>1982</year></dates><keywords><keyword>Abdominal Muscles/metabolism</keyword><keyword>Acidosis/complications/*metabolism</keyword><keyword>Animals</keyword><keyword>Cardiac Output, Low/complications/*metabolism</keyword><keyword>Diaphragm/metabolism</keyword><keyword>Dogs</keyword><keyword>Glycogen/metabolism</keyword><keyword>Intercostal Muscles/metabolism</keyword><keyword>Lactates/*metabolism</keyword><keyword>Muscles/*metabolism</keyword><keyword>*Respiration</keyword><keyword>Shock, Cardiogenic/metabolism</keyword></keywords><isbn>0003-0805 (Print)&#xD;0003-0805</isbn><titles><title>Respiratory muscle contribution to lactic acidosis in low cardiac output</title><secondary-title>Am Rev Respir Dis</secondary-title><alt-title>The American review of respiratory disease</alt-title></titles><pages>648-52</pages><number>4</number><contributors><authors><author>Aubier, M.</author><author>Viires, N.</author><author>Syllie, G.</author><author>Mozes, R.</author><author>Roussos, C.</author></authors></contributors><edition>1982/10/01</edition><language>eng</language><added-date format="utc">1510082491</added-date><ref-type name="Journal Article">17</ref-type><remote-database-provider>NLM</remote-database-provider><rec-number>252</rec-number><last-updated-date format="utc">1510082491</last-updated-date><accession-num>6214978</accession-num><electronic-resource-num>10.1164/arrd.1982.126.4.648</electronic-resource-num><volume>126</volume></record></Cite></EndNote>(Aubier et al., 1982). These reducing effects are offset during surgery by the associated stress response. However, the values obtained in the current study were recorded before surgery began, so a straightforward explanation is not forthcoming. The differences in oxygen consumption were not statistically significant and both mean values were approximately 5mL kg-1 minute-1. This is considerably less than the oxygen flow recommendations for a circle breathing system (10 mL kg-1 minute-1) ADDIN EN.CITE <EndNote><Cite><Author>Duke-Novakovski</Author><Year>2016</Year><IDText>BSAVA manual of canine and feline anaesthesia and analgesia</IDText><DisplayText>(Duke-Novakovski, 2016)</DisplayText><record><isbn>1905319614</isbn><titles><title>BSAVA manual of canine and feline anaesthesia and analgesia</title></titles><contributors><authors><author>Duke-Novakovski, Tanya</author></authors></contributors><added-date format="utc">1528964155</added-date><ref-type name="Book">6</ref-type><dates><year>2016</year></dates><rec-number>285</rec-number><publisher>John Wiley &amp; Sons</publisher><last-updated-date format="utc">1528964155</last-updated-date></record></Cite></EndNote>(Duke-Novakovski, 2016). The limits of agreement for the formulae were wide and as values of oxygen consumption increased the difference between the two methods became greater. The wide limits of agreement are unacceptable in a clinical context and this demonstrates that the two methods are not interchangeable.Factors affecting metabolic rate and therefore VO2 include alterations in body temperature, the subject’s tissue composition, disease, the drugs used for sedation and anaesthesia and activation of a stress response. These may be secondary to - amongst other things - tracheal intubation and surgery PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5LaW5nPC9BdXRob3I+PFllYXI+MTk1MTwvWWVhcj48SURU

ZXh0PlJlZmxleCBjaXJjdWxhdG9yeSByZXNwb25zZXMgdG8gZGlyZWN0IGxhcnluZ29zY29weSBh

bmQgdHJhY2hlYWwgaW50dWJhdGlvbiBwZXJmb3JtZWQgZHVyaW5nIGdlbmVyYWwgYW5lc3RoZXNp

YTwvSURUZXh0PjxEaXNwbGF5VGV4dD4oS2luZyBldCBhbC4sIDE5NTEsIFJvYmluc29uIGV0IGFs

LiwgMTk4Myk8L0Rpc3BsYXlUZXh0PjxyZWNvcmQ+PGRhdGVzPjxwdWItZGF0ZXM+PGRhdGU+U2Vw

PC9kYXRlPjwvcHViLWRhdGVzPjx5ZWFyPjE5NTE8L3llYXI+PC9kYXRlcz48a2V5d29yZHM+PGtl

eXdvcmQ+KkFuZXN0aGVzaWE8L2tleXdvcmQ+PGtleXdvcmQ+KkFuZXN0aGVzaWEsIEdlbmVyYWw8

L2tleXdvcmQ+PGtleXdvcmQ+KkNhcmRpb3Zhc2N1bGFyIFN5c3RlbTwva2V5d29yZD48a2V5d29y

ZD5IdW1hbnM8L2tleXdvcmQ+PGtleXdvcmQ+KkludHViYXRpb24sIEludHJhdHJhY2hlYWw8L2tl

eXdvcmQ+PGtleXdvcmQ+KkxhcnluZ29zY29weTwva2V5d29yZD48a2V5d29yZD4qUmVmbGV4PC9r

ZXl3b3JkPjxrZXl3b3JkPipBbmVzdGhlc2lhLCBlbmRvdHJhY2hlYWw8L2tleXdvcmQ+PGtleXdv

cmQ+KkNhcmRpb3Zhc2N1bGFyIHN5c3RlbTwva2V5d29yZD48L2tleXdvcmRzPjxpc2JuPjAwMDMt

MzAyMiAoUHJpbnQpJiN4RDswMDAzLTMwMjI8L2lzYm4+PHRpdGxlcz48dGl0bGU+UmVmbGV4IGNp

cmN1bGF0b3J5IHJlc3BvbnNlcyB0byBkaXJlY3QgbGFyeW5nb3Njb3B5IGFuZCB0cmFjaGVhbCBp

bnR1YmF0aW9uIHBlcmZvcm1lZCBkdXJpbmcgZ2VuZXJhbCBhbmVzdGhlc2lhPC90aXRsZT48c2Vj

b25kYXJ5LXRpdGxlPkFuZXN0aGVzaW9sb2d5PC9zZWNvbmRhcnktdGl0bGU+PGFsdC10aXRsZT5B

bmVzdGhlc2lvbG9neTwvYWx0LXRpdGxlPjwvdGl0bGVzPjxwYWdlcz41NTYtNjY8L3BhZ2VzPjxu

dW1iZXI+NTwvbnVtYmVyPjxjb250cmlidXRvcnM+PGF1dGhvcnM+PGF1dGhvcj5LaW5nLCBCLiBE

LjwvYXV0aG9yPjxhdXRob3I+SGFycmlzLCBMLiBDLiwgSnIuPC9hdXRob3I+PGF1dGhvcj5HcmVp

ZmVuc3RlaW4sIEYuIEUuPC9hdXRob3I+PGF1dGhvcj5FbGRlciwgSi4gRC4sIEpyLjwvYXV0aG9y

PjxhdXRob3I+RHJpcHBzLCBSLiBELjwvYXV0aG9yPjwvYXV0aG9ycz48L2NvbnRyaWJ1dG9ycz48

ZWRpdGlvbj4xOTUxLzA5LzAxPC9lZGl0aW9uPjxsYW5ndWFnZT5lbmc8L2xhbmd1YWdlPjxhZGRl

ZC1kYXRlIGZvcm1hdD0idXRjIj4xNDg5NTA1NTUyPC9hZGRlZC1kYXRlPjxyZWYtdHlwZSBuYW1l

PSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48cmVtb3RlLWRhdGFiYXNlLXByb3ZpZGVy

Pk5MTTwvcmVtb3RlLWRhdGFiYXNlLXByb3ZpZGVyPjxyZWMtbnVtYmVyPjE4OTwvcmVjLW51bWJl

cj48bGFzdC11cGRhdGVkLWRhdGUgZm9ybWF0PSJ1dGMiPjE0ODk1MDU1NTI8L2xhc3QtdXBkYXRl

ZC1kYXRlPjxhY2Nlc3Npb24tbnVtPjE0ODY4ODkxPC9hY2Nlc3Npb24tbnVtPjx2b2x1bWU+MTI8

L3ZvbHVtZT48L3JlY29yZD48L0NpdGU+PENpdGU+PEF1dGhvcj5Sb2JpbnNvbjwvQXV0aG9yPjxZ

ZWFyPjE5ODM8L1llYXI+PElEVGV4dD5UaGUgZWZmZWN0cyBvZiBib2R5IHNpemUgYW5kIHRlbXBl

cmF0dXJlIG9uIG1ldGFib2xpYyByYXRlIG9mIG9yZ2FuaXNtczwvSURUZXh0PjxyZWNvcmQ+PGRh

dGVzPjxwdWItZGF0ZXM+PGRhdGU+MTk4My8wMi8wMTwvZGF0ZT48L3B1Yi1kYXRlcz48eWVhcj4x

OTgzPC95ZWFyPjwvZGF0ZXM+PHVybHM+PHJlbGF0ZWQtdXJscz48dXJsPmh0dHA6Ly9keC5kb2ku

b3JnLzEwLjExMzkvejgzLTAzNzwvdXJsPjwvcmVsYXRlZC11cmxzPjwvdXJscz48aXNibj4wMDA4

LTQzMDE8L2lzYm4+PHRpdGxlcz48dGl0bGU+VGhlIGVmZmVjdHMgb2YgYm9keSBzaXplIGFuZCB0

ZW1wZXJhdHVyZSBvbiBtZXRhYm9saWMgcmF0ZSBvZiBvcmdhbmlzbXM8L3RpdGxlPjxzZWNvbmRh

cnktdGl0bGU+Q2FuYWRpYW4gSm91cm5hbCBvZiBab29sb2d5PC9zZWNvbmRhcnktdGl0bGU+PC90

aXRsZXM+PHBhZ2VzPjI4MS0yODg8L3BhZ2VzPjxudW1iZXI+MjwvbnVtYmVyPjxhY2Nlc3MtZGF0

ZT4yMDE3LzAzLzE0PC9hY2Nlc3MtZGF0ZT48Y29udHJpYnV0b3JzPjxhdXRob3JzPjxhdXRob3I+

Um9iaW5zb24sIFcuIFJpY2hhcmQ8L2F1dGhvcj48YXV0aG9yPlBldGVycywgUm9iZXJ0IEhlbnJ5

PC9hdXRob3I+PGF1dGhvcj5aaW1tZXJtYW5uLCBKZXNzPC9hdXRob3I+PC9hdXRob3JzPjwvY29u

dHJpYnV0b3JzPjxhZGRlZC1kYXRlIGZvcm1hdD0idXRjIj4xNDg5NTA1NzY2PC9hZGRlZC1kYXRl

PjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48cmVjLW51bWJl

cj4xOTA8L3JlYy1udW1iZXI+PHB1Ymxpc2hlcj5OUkMgUmVzZWFyY2ggUHJlc3M8L3B1Ymxpc2hl

cj48bGFzdC11cGRhdGVkLWRhdGUgZm9ybWF0PSJ1dGMiPjE0ODk1MDU3NjY8L2xhc3QtdXBkYXRl

ZC1kYXRlPjxlbGVjdHJvbmljLXJlc291cmNlLW51bT4xMC4xMTM5L3o4My0wMzc8L2VsZWN0cm9u

aWMtcmVzb3VyY2UtbnVtPjx2b2x1bWU+NjE8L3ZvbHVtZT48L3JlY29yZD48L0NpdGU+PC9FbmRO

b3RlPn==

ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5LaW5nPC9BdXRob3I+PFllYXI+MTk1MTwvWWVhcj48SURU

ZXh0PlJlZmxleCBjaXJjdWxhdG9yeSByZXNwb25zZXMgdG8gZGlyZWN0IGxhcnluZ29zY29weSBh

bmQgdHJhY2hlYWwgaW50dWJhdGlvbiBwZXJmb3JtZWQgZHVyaW5nIGdlbmVyYWwgYW5lc3RoZXNp

YTwvSURUZXh0PjxEaXNwbGF5VGV4dD4oS2luZyBldCBhbC4sIDE5NTEsIFJvYmluc29uIGV0IGFs

LiwgMTk4Myk8L0Rpc3BsYXlUZXh0PjxyZWNvcmQ+PGRhdGVzPjxwdWItZGF0ZXM+PGRhdGU+U2Vw

PC9kYXRlPjwvcHViLWRhdGVzPjx5ZWFyPjE5NTE8L3llYXI+PC9kYXRlcz48a2V5d29yZHM+PGtl

eXdvcmQ+KkFuZXN0aGVzaWE8L2tleXdvcmQ+PGtleXdvcmQ+KkFuZXN0aGVzaWEsIEdlbmVyYWw8

L2tleXdvcmQ+PGtleXdvcmQ+KkNhcmRpb3Zhc2N1bGFyIFN5c3RlbTwva2V5d29yZD48a2V5d29y

ZD5IdW1hbnM8L2tleXdvcmQ+PGtleXdvcmQ+KkludHViYXRpb24sIEludHJhdHJhY2hlYWw8L2tl

eXdvcmQ+PGtleXdvcmQ+KkxhcnluZ29zY29weTwva2V5d29yZD48a2V5d29yZD4qUmVmbGV4PC9r

ZXl3b3JkPjxrZXl3b3JkPipBbmVzdGhlc2lhLCBlbmRvdHJhY2hlYWw8L2tleXdvcmQ+PGtleXdv

cmQ+KkNhcmRpb3Zhc2N1bGFyIHN5c3RlbTwva2V5d29yZD48L2tleXdvcmRzPjxpc2JuPjAwMDMt

MzAyMiAoUHJpbnQpJiN4RDswMDAzLTMwMjI8L2lzYm4+PHRpdGxlcz48dGl0bGU+UmVmbGV4IGNp

cmN1bGF0b3J5IHJlc3BvbnNlcyB0byBkaXJlY3QgbGFyeW5nb3Njb3B5IGFuZCB0cmFjaGVhbCBp

bnR1YmF0aW9uIHBlcmZvcm1lZCBkdXJpbmcgZ2VuZXJhbCBhbmVzdGhlc2lhPC90aXRsZT48c2Vj

b25kYXJ5LXRpdGxlPkFuZXN0aGVzaW9sb2d5PC9zZWNvbmRhcnktdGl0bGU+PGFsdC10aXRsZT5B

bmVzdGhlc2lvbG9neTwvYWx0LXRpdGxlPjwvdGl0bGVzPjxwYWdlcz41NTYtNjY8L3BhZ2VzPjxu

dW1iZXI+NTwvbnVtYmVyPjxjb250cmlidXRvcnM+PGF1dGhvcnM+PGF1dGhvcj5LaW5nLCBCLiBE

LjwvYXV0aG9yPjxhdXRob3I+SGFycmlzLCBMLiBDLiwgSnIuPC9hdXRob3I+PGF1dGhvcj5HcmVp

ZmVuc3RlaW4sIEYuIEUuPC9hdXRob3I+PGF1dGhvcj5FbGRlciwgSi4gRC4sIEpyLjwvYXV0aG9y

PjxhdXRob3I+RHJpcHBzLCBSLiBELjwvYXV0aG9yPjwvYXV0aG9ycz48L2NvbnRyaWJ1dG9ycz48

ZWRpdGlvbj4xOTUxLzA5LzAxPC9lZGl0aW9uPjxsYW5ndWFnZT5lbmc8L2xhbmd1YWdlPjxhZGRl

ZC1kYXRlIGZvcm1hdD0idXRjIj4xNDg5NTA1NTUyPC9hZGRlZC1kYXRlPjxyZWYtdHlwZSBuYW1l

PSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48cmVtb3RlLWRhdGFiYXNlLXByb3ZpZGVy

Pk5MTTwvcmVtb3RlLWRhdGFiYXNlLXByb3ZpZGVyPjxyZWMtbnVtYmVyPjE4OTwvcmVjLW51bWJl

cj48bGFzdC11cGRhdGVkLWRhdGUgZm9ybWF0PSJ1dGMiPjE0ODk1MDU1NTI8L2xhc3QtdXBkYXRl

ZC1kYXRlPjxhY2Nlc3Npb24tbnVtPjE0ODY4ODkxPC9hY2Nlc3Npb24tbnVtPjx2b2x1bWU+MTI8

L3ZvbHVtZT48L3JlY29yZD48L0NpdGU+PENpdGU+PEF1dGhvcj5Sb2JpbnNvbjwvQXV0aG9yPjxZ

ZWFyPjE5ODM8L1llYXI+PElEVGV4dD5UaGUgZWZmZWN0cyBvZiBib2R5IHNpemUgYW5kIHRlbXBl

cmF0dXJlIG9uIG1ldGFib2xpYyByYXRlIG9mIG9yZ2FuaXNtczwvSURUZXh0PjxyZWNvcmQ+PGRh

dGVzPjxwdWItZGF0ZXM+PGRhdGU+MTk4My8wMi8wMTwvZGF0ZT48L3B1Yi1kYXRlcz48eWVhcj4x

OTgzPC95ZWFyPjwvZGF0ZXM+PHVybHM+PHJlbGF0ZWQtdXJscz48dXJsPmh0dHA6Ly9keC5kb2ku

b3JnLzEwLjExMzkvejgzLTAzNzwvdXJsPjwvcmVsYXRlZC11cmxzPjwvdXJscz48aXNibj4wMDA4

LTQzMDE8L2lzYm4+PHRpdGxlcz48dGl0bGU+VGhlIGVmZmVjdHMgb2YgYm9keSBzaXplIGFuZCB0

ZW1wZXJhdHVyZSBvbiBtZXRhYm9saWMgcmF0ZSBvZiBvcmdhbmlzbXM8L3RpdGxlPjxzZWNvbmRh

cnktdGl0bGU+Q2FuYWRpYW4gSm91cm5hbCBvZiBab29sb2d5PC9zZWNvbmRhcnktdGl0bGU+PC90

aXRsZXM+PHBhZ2VzPjI4MS0yODg8L3BhZ2VzPjxudW1iZXI+MjwvbnVtYmVyPjxhY2Nlc3MtZGF0

ZT4yMDE3LzAzLzE0PC9hY2Nlc3MtZGF0ZT48Y29udHJpYnV0b3JzPjxhdXRob3JzPjxhdXRob3I+

Um9iaW5zb24sIFcuIFJpY2hhcmQ8L2F1dGhvcj48YXV0aG9yPlBldGVycywgUm9iZXJ0IEhlbnJ5

PC9hdXRob3I+PGF1dGhvcj5aaW1tZXJtYW5uLCBKZXNzPC9hdXRob3I+PC9hdXRob3JzPjwvY29u

dHJpYnV0b3JzPjxhZGRlZC1kYXRlIGZvcm1hdD0idXRjIj4xNDg5NTA1NzY2PC9hZGRlZC1kYXRl

PjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48cmVjLW51bWJl

cj4xOTA8L3JlYy1udW1iZXI+PHB1Ymxpc2hlcj5OUkMgUmVzZWFyY2ggUHJlc3M8L3B1Ymxpc2hl

cj48bGFzdC11cGRhdGVkLWRhdGUgZm9ybWF0PSJ1dGMiPjE0ODk1MDU3NjY8L2xhc3QtdXBkYXRl

ZC1kYXRlPjxlbGVjdHJvbmljLXJlc291cmNlLW51bT4xMC4xMTM5L3o4My0wMzc8L2VsZWN0cm9u

aWMtcmVzb3VyY2UtbnVtPjx2b2x1bWU+NjE8L3ZvbHVtZT48L3JlY29yZD48L0NpdGU+PC9FbmRO

b3RlPn==

ADDIN EN.CITE.DATA (King et al., 1951, Robinson et al., 1983). Brody’s formula excludes these factors whilst Sykes’ method does not, explaining the greater variability between VO2 values obtained with the latter method. Every effort was made to reduce heat loss in the dogs studied but temperatures as low as 37°C were recorded in some dogs. This represents mild hypothermia and can be attributed to abolished behavioural responses, increased heat loss, the cooling effect of anaesthetic gases and vapours and reduced heat production due to decreased muscle activity and brain metabolism. In humans, hypothermia decreases cerebral metabolic rate by approximately 8% for each degree Celsius below normal. Given that the brain accounts for 25% of total body oxygen consumption, hypothermia may alter VO2 considerably. However, in the current study, reduced core temperatures were not associated with lower measured VO2 values, which means other, unidentified factors were present. It is known that some types of neoplasia and renal disease can lead to increased VO2 PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5UYW5ha2E8L0F1dGhvcj48WWVhcj4yMDEwPC9ZZWFyPjxJ

RFRleHQ+VGhlIHJvbGUgb2YgaHlwb3hpYSwgaW5jcmVhc2VkIG94eWdlbiBjb25zdW1wdGlvbiwg

YW5kIGh5cG94aWEtaW5kdWNpYmxlIGZhY3Rvci0xIGFscGhhIGluIHByb2dyZXNzaW9uIG9mIGNo

cm9uaWMga2lkbmV5IGRpc2Vhc2U8L0lEVGV4dD48RGlzcGxheVRleHQ+KFRhbmFrYSBhbmQgTmFu

Z2FrdSwgMjAxMCwgTWFjYmV0aCBhbmQgQmVrZXNpLCAxOTYyKTwvRGlzcGxheVRleHQ+PHJlY29y

ZD48ZGF0ZXM+PHB1Yi1kYXRlcz48ZGF0ZT5KYW48L2RhdGU+PC9wdWItZGF0ZXM+PHllYXI+MjAx

MDwveWVhcj48L2RhdGVzPjxrZXl3b3Jkcz48a2V5d29yZD5BbmltYWxzPC9rZXl3b3JkPjxrZXl3

b3JkPkh1bWFuczwva2V5d29yZD48a2V5d29yZD5IeXBveGlhLypwaHlzaW9wYXRob2xvZ3k8L2tl

eXdvcmQ+PGtleXdvcmQ+SHlwb3hpYS1JbmR1Y2libGUgRmFjdG9yIDEsIGFscGhhIFN1YnVuaXQv

YW50YWdvbmlzdHMgJmFtcDs8L2tleXdvcmQ+PGtleXdvcmQ+aW5oaWJpdG9ycy9jaGVtaXN0cnkv

KnBoeXNpb2xvZ3k8L2tleXdvcmQ+PGtleXdvcmQ+S2lkbmV5L2Jsb29kIHN1cHBseS9pbmp1cmll

cy9waHlzaW9wYXRob2xvZ3k8L2tleXdvcmQ+PGtleXdvcmQ+T3h5Z2VuIENvbnN1bXB0aW9uPC9r

ZXl3b3JkPjxrZXl3b3JkPlByb2NvbGxhZ2VuLVByb2xpbmUgRGlveHlnZW5hc2UvYW50YWdvbmlz

dHMgJmFtcDsgaW5oaWJpdG9ycy9jaGVtaXN0cnkvcGh5c2lvbG9neTwva2V5d29yZD48a2V5d29y

ZD5Qcm90ZWluIFN0cnVjdHVyZSwgVGVydGlhcnk8L2tleXdvcmQ+PGtleXdvcmQ+UmVuYWwgSW5z

dWZmaWNpZW5jeSwgQ2hyb25pYy9kcnVnIHRoZXJhcHkvKmV0aW9sb2d5L3BoeXNpb3BhdGhvbG9n

eTwva2V5d29yZD48L2tleXdvcmRzPjxpc2JuPjEwNjItNDgyMTwvaXNibj48dGl0bGVzPjx0aXRs

ZT5UaGUgcm9sZSBvZiBoeXBveGlhLCBpbmNyZWFzZWQgb3h5Z2VuIGNvbnN1bXB0aW9uLCBhbmQg

aHlwb3hpYS1pbmR1Y2libGUgZmFjdG9yLTEgYWxwaGEgaW4gcHJvZ3Jlc3Npb24gb2YgY2hyb25p

YyBraWRuZXkgZGlzZWFzZTwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5DdXJyIE9waW4gTmVwaHJv

bCBIeXBlcnRlbnM8L3NlY29uZGFyeS10aXRsZT48YWx0LXRpdGxlPkN1cnJlbnQgb3BpbmlvbiBp

biBuZXBocm9sb2d5IGFuZCBoeXBlcnRlbnNpb248L2FsdC10aXRsZT48L3RpdGxlcz48cGFnZXM+

NDMtNTA8L3BhZ2VzPjxudW1iZXI+MTwvbnVtYmVyPjxjb250cmlidXRvcnM+PGF1dGhvcnM+PGF1

dGhvcj5UYW5ha2EsIFQuPC9hdXRob3I+PGF1dGhvcj5OYW5nYWt1LCBNLjwvYXV0aG9yPjwvYXV0

aG9ycz48L2NvbnRyaWJ1dG9ycz48ZWRpdGlvbj4yMDA5LzA5LzI2PC9lZGl0aW9uPjxsYW5ndWFn

ZT5lbmc8L2xhbmd1YWdlPjxhZGRlZC1kYXRlIGZvcm1hdD0idXRjIj4xNDg5NTA2MDc0PC9hZGRl

ZC1kYXRlPjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48YXV0

aC1hZGRyZXNzPkRpdmlzaW9uIGZvciBIZWFsdGggU2VydmljZSBQcm9tb3Rpb24sIFVuaXZlcnNp

dHkgb2YgVG9reW8sIEJ1bmt5by1rdSwgVG9reW8sIEphcGFuLjwvYXV0aC1hZGRyZXNzPjxyZW1v

dGUtZGF0YWJhc2UtcHJvdmlkZXI+TkxNPC9yZW1vdGUtZGF0YWJhc2UtcHJvdmlkZXI+PHJlYy1u

dW1iZXI+MTkxPC9yZWMtbnVtYmVyPjxsYXN0LXVwZGF0ZWQtZGF0ZSBmb3JtYXQ9InV0YyI+MTQ4

OTUwNjA3NDwvbGFzdC11cGRhdGVkLWRhdGU+PGFjY2Vzc2lvbi1udW0+MTk3NzkzMzc8L2FjY2Vz

c2lvbi1udW0+PGVsZWN0cm9uaWMtcmVzb3VyY2UtbnVtPjEwLjEwOTcvTU5ILjBiMDEzZTMyODMz

MjhlZWQ8L2VsZWN0cm9uaWMtcmVzb3VyY2UtbnVtPjx2b2x1bWU+MTk8L3ZvbHVtZT48L3JlY29y

ZD48L0NpdGU+PENpdGU+PEF1dGhvcj5NYWNiZXRoPC9BdXRob3I+PFllYXI+MTk2MjwvWWVhcj48

SURUZXh0Pk94eWdlbiBDb25zdW1wdGlvbiBhbmQgQW5hZXJvYmljIEdseWNvbHlzaXMgb2YgSHVt

YW4gTWFsaWduYW50IGFuZCBOb3JtYWwgVGlzc3VlPC9JRFRleHQ+PHJlY29yZD48dXJscz48cmVs

YXRlZC11cmxzPjx1cmw+aHR0cDovL2NhbmNlcnJlcy5hYWNyam91cm5hbHMub3JnL2NvbnRlbnQv

MjIvMi8yNDQuYWJzdHJhY3Q8L3VybD48L3JlbGF0ZWQtdXJscz48L3VybHM+PHRpdGxlcz48dGl0

bGU+T3h5Z2VuIENvbnN1bXB0aW9uIGFuZCBBbmFlcm9iaWMgR2x5Y29seXNpcyBvZiBIdW1hbiBN

YWxpZ25hbnQgYW5kIE5vcm1hbCBUaXNzdWU8L3RpdGxlPjxzZWNvbmRhcnktdGl0bGU+Q2FuY2Vy

IFJlc2VhcmNoPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBhZ2VzPjI0NDwvcGFnZXM+PG51

bWJlcj4yPC9udW1iZXI+PGNvbnRyaWJ1dG9ycz48YXV0aG9ycz48YXV0aG9yPk1hY2JldGgsIFJv

YmVydCBBLiBMLjwvYXV0aG9yPjxhdXRob3I+QmVrZXNpLCBKLiBHZW9yZ2U8L2F1dGhvcj48L2F1

dGhvcnM+PC9jb250cmlidXRvcnM+PGFkZGVkLWRhdGUgZm9ybWF0PSJ1dGMiPjE0ODk1MDcxMzU8

L2FkZGVkLWRhdGU+PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10eXBl

PjxkYXRlcz48eWVhcj4xOTYyPC95ZWFyPjwvZGF0ZXM+PHJlYy1udW1iZXI+MTkyPC9yZWMtbnVt

YmVyPjxsYXN0LXVwZGF0ZWQtZGF0ZSBmb3JtYXQ9InV0YyI+MTQ4OTUwNzEzNTwvbGFzdC11cGRh

dGVkLWRhdGU+PHZvbHVtZT4yMjwvdm9sdW1lPjwvcmVjb3JkPjwvQ2l0ZT48L0VuZE5vdGU+

ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5UYW5ha2E8L0F1dGhvcj48WWVhcj4yMDEwPC9ZZWFyPjxJ

RFRleHQ+VGhlIHJvbGUgb2YgaHlwb3hpYSwgaW5jcmVhc2VkIG94eWdlbiBjb25zdW1wdGlvbiwg

YW5kIGh5cG94aWEtaW5kdWNpYmxlIGZhY3Rvci0xIGFscGhhIGluIHByb2dyZXNzaW9uIG9mIGNo

cm9uaWMga2lkbmV5IGRpc2Vhc2U8L0lEVGV4dD48RGlzcGxheVRleHQ+KFRhbmFrYSBhbmQgTmFu

Z2FrdSwgMjAxMCwgTWFjYmV0aCBhbmQgQmVrZXNpLCAxOTYyKTwvRGlzcGxheVRleHQ+PHJlY29y

ZD48ZGF0ZXM+PHB1Yi1kYXRlcz48ZGF0ZT5KYW48L2RhdGU+PC9wdWItZGF0ZXM+PHllYXI+MjAx

MDwveWVhcj48L2RhdGVzPjxrZXl3b3Jkcz48a2V5d29yZD5BbmltYWxzPC9rZXl3b3JkPjxrZXl3

b3JkPkh1bWFuczwva2V5d29yZD48a2V5d29yZD5IeXBveGlhLypwaHlzaW9wYXRob2xvZ3k8L2tl

eXdvcmQ+PGtleXdvcmQ+SHlwb3hpYS1JbmR1Y2libGUgRmFjdG9yIDEsIGFscGhhIFN1YnVuaXQv

YW50YWdvbmlzdHMgJmFtcDs8L2tleXdvcmQ+PGtleXdvcmQ+aW5oaWJpdG9ycy9jaGVtaXN0cnkv

KnBoeXNpb2xvZ3k8L2tleXdvcmQ+PGtleXdvcmQ+S2lkbmV5L2Jsb29kIHN1cHBseS9pbmp1cmll

cy9waHlzaW9wYXRob2xvZ3k8L2tleXdvcmQ+PGtleXdvcmQ+T3h5Z2VuIENvbnN1bXB0aW9uPC9r

ZXl3b3JkPjxrZXl3b3JkPlByb2NvbGxhZ2VuLVByb2xpbmUgRGlveHlnZW5hc2UvYW50YWdvbmlz

dHMgJmFtcDsgaW5oaWJpdG9ycy9jaGVtaXN0cnkvcGh5c2lvbG9neTwva2V5d29yZD48a2V5d29y

ZD5Qcm90ZWluIFN0cnVjdHVyZSwgVGVydGlhcnk8L2tleXdvcmQ+PGtleXdvcmQ+UmVuYWwgSW5z

dWZmaWNpZW5jeSwgQ2hyb25pYy9kcnVnIHRoZXJhcHkvKmV0aW9sb2d5L3BoeXNpb3BhdGhvbG9n

eTwva2V5d29yZD48L2tleXdvcmRzPjxpc2JuPjEwNjItNDgyMTwvaXNibj48dGl0bGVzPjx0aXRs

ZT5UaGUgcm9sZSBvZiBoeXBveGlhLCBpbmNyZWFzZWQgb3h5Z2VuIGNvbnN1bXB0aW9uLCBhbmQg

aHlwb3hpYS1pbmR1Y2libGUgZmFjdG9yLTEgYWxwaGEgaW4gcHJvZ3Jlc3Npb24gb2YgY2hyb25p

YyBraWRuZXkgZGlzZWFzZTwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5DdXJyIE9waW4gTmVwaHJv

bCBIeXBlcnRlbnM8L3NlY29uZGFyeS10aXRsZT48YWx0LXRpdGxlPkN1cnJlbnQgb3BpbmlvbiBp

biBuZXBocm9sb2d5IGFuZCBoeXBlcnRlbnNpb248L2FsdC10aXRsZT48L3RpdGxlcz48cGFnZXM+

NDMtNTA8L3BhZ2VzPjxudW1iZXI+MTwvbnVtYmVyPjxjb250cmlidXRvcnM+PGF1dGhvcnM+PGF1

dGhvcj5UYW5ha2EsIFQuPC9hdXRob3I+PGF1dGhvcj5OYW5nYWt1LCBNLjwvYXV0aG9yPjwvYXV0

aG9ycz48L2NvbnRyaWJ1dG9ycz48ZWRpdGlvbj4yMDA5LzA5LzI2PC9lZGl0aW9uPjxsYW5ndWFn

ZT5lbmc8L2xhbmd1YWdlPjxhZGRlZC1kYXRlIGZvcm1hdD0idXRjIj4xNDg5NTA2MDc0PC9hZGRl

ZC1kYXRlPjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48YXV0

aC1hZGRyZXNzPkRpdmlzaW9uIGZvciBIZWFsdGggU2VydmljZSBQcm9tb3Rpb24sIFVuaXZlcnNp

dHkgb2YgVG9reW8sIEJ1bmt5by1rdSwgVG9reW8sIEphcGFuLjwvYXV0aC1hZGRyZXNzPjxyZW1v

dGUtZGF0YWJhc2UtcHJvdmlkZXI+TkxNPC9yZW1vdGUtZGF0YWJhc2UtcHJvdmlkZXI+PHJlYy1u

dW1iZXI+MTkxPC9yZWMtbnVtYmVyPjxsYXN0LXVwZGF0ZWQtZGF0ZSBmb3JtYXQ9InV0YyI+MTQ4

OTUwNjA3NDwvbGFzdC11cGRhdGVkLWRhdGU+PGFjY2Vzc2lvbi1udW0+MTk3NzkzMzc8L2FjY2Vz

c2lvbi1udW0+PGVsZWN0cm9uaWMtcmVzb3VyY2UtbnVtPjEwLjEwOTcvTU5ILjBiMDEzZTMyODMz

MjhlZWQ8L2VsZWN0cm9uaWMtcmVzb3VyY2UtbnVtPjx2b2x1bWU+MTk8L3ZvbHVtZT48L3JlY29y

ZD48L0NpdGU+PENpdGU+PEF1dGhvcj5NYWNiZXRoPC9BdXRob3I+PFllYXI+MTk2MjwvWWVhcj48

SURUZXh0Pk94eWdlbiBDb25zdW1wdGlvbiBhbmQgQW5hZXJvYmljIEdseWNvbHlzaXMgb2YgSHVt

YW4gTWFsaWduYW50IGFuZCBOb3JtYWwgVGlzc3VlPC9JRFRleHQ+PHJlY29yZD48dXJscz48cmVs

YXRlZC11cmxzPjx1cmw+aHR0cDovL2NhbmNlcnJlcy5hYWNyam91cm5hbHMub3JnL2NvbnRlbnQv

MjIvMi8yNDQuYWJzdHJhY3Q8L3VybD48L3JlbGF0ZWQtdXJscz48L3VybHM+PHRpdGxlcz48dGl0

bGU+T3h5Z2VuIENvbnN1bXB0aW9uIGFuZCBBbmFlcm9iaWMgR2x5Y29seXNpcyBvZiBIdW1hbiBN

YWxpZ25hbnQgYW5kIE5vcm1hbCBUaXNzdWU8L3RpdGxlPjxzZWNvbmRhcnktdGl0bGU+Q2FuY2Vy

IFJlc2VhcmNoPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBhZ2VzPjI0NDwvcGFnZXM+PG51

bWJlcj4yPC9udW1iZXI+PGNvbnRyaWJ1dG9ycz48YXV0aG9ycz48YXV0aG9yPk1hY2JldGgsIFJv

YmVydCBBLiBMLjwvYXV0aG9yPjxhdXRob3I+QmVrZXNpLCBKLiBHZW9yZ2U8L2F1dGhvcj48L2F1

dGhvcnM+PC9jb250cmlidXRvcnM+PGFkZGVkLWRhdGUgZm9ybWF0PSJ1dGMiPjE0ODk1MDcxMzU8

L2FkZGVkLWRhdGU+PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10eXBl

PjxkYXRlcz48eWVhcj4xOTYyPC95ZWFyPjwvZGF0ZXM+PHJlYy1udW1iZXI+MTkyPC9yZWMtbnVt

YmVyPjxsYXN0LXVwZGF0ZWQtZGF0ZSBmb3JtYXQ9InV0YyI+MTQ4OTUwNzEzNTwvbGFzdC11cGRh

dGVkLWRhdGU+PHZvbHVtZT4yMjwvdm9sdW1lPjwvcmVjb3JkPjwvQ2l0ZT48L0VuZE5vdGU+

ADDIN EN.CITE.DATA (Tanaka and Nangaku, 2010, Macbeth and Bekesi, 1962). Brody’s formula was proposed using data from presumably healthy animals and so this might have accounted for some of the differences encountered in the current study. Furthermore Brody studied a large number of different animals and the value is likely to be an average from different species. A previous study by Haskins et al., (2005), which collated cardiopulmonary variables from unsedated, instrumented dogs, found a VO2 of 6.0 ± 2.6 mL kg -1 minute-1 ADDIN EN.CITE <EndNote><Cite><Author>Haskins</Author><Year>2005</Year><IDText>Reference Cardiopulmonary Values in Normal Dogs</IDText><DisplayText>(Haskins et al., 2005)</DisplayText><record><dates><pub-dates><date>//</date></pub-dates><year>2005</year></dates><urls><related-urls><url> Cardiopulmonary Values in Normal Dogs</title><secondary-title>Comparative Medicine</secondary-title></titles><pages>156-161</pages><number>2</number><contributors><authors><author>Haskins, Steve</author><author>Pascoe, Peter J.</author><author>Ilkiw, Jan E.</author><author>Fudge, James</author><author>Hopper, Kate</author><author>Aldrich, Janet</author></authors></contributors><added-date format="utc">1528904166</added-date><ref-type name="Journal Article">17</ref-type><rec-number>284</rec-number><last-updated-date format="utc">1528904166</last-updated-date><volume>55</volume></record></Cite></EndNote>(Haskins et al., 2005). This suggests that dogs may have a higher VO2 than previously indicated suggested by Brody’s formula.There were several limitations to the study. Body condition and ASA physical status scores were not taken into account. Preferably, In addition, body temperature would should have been maintained within normal physiological limits (38.3-38.9 °C). It is possible that the useing of a range of anaesthetic techniques in the current study increased variance in the data recorded. However, the clinical nature of the study rendered the use of a standardised protocol infeasible. One further major limitation was the lack of calibration of the spirometer. While the anaesthetic machine we used hads been recently purchased and commissioned check by the manufacturer, no calibration was done at the time of the study. Further work would include standardising the anaesthetic protocol and reducing pathophysiological variation by only including ASA 1 or 2 animals would limit some of the variability inherent in our study. In addition, segregating data according to body condition score, fitness and age categories may allow further insight into how VO2 varies with body composition. Obese dogs with higher proportions of adipose tissue compared with normal dogs may account for alterations in VO2 and this may be an area for further study. Research in humans suggests that oxygen consumption decreases with the degree of obesity ADDIN EN.CITE <EndNote><Cite><Author>Hallgren</Author><Year>1989</Year><IDText>Influence of age, fat cell weight, and obesity on O2 consumption of human adipose tissue</IDText><DisplayText>(Hallgren et al., 1989)</DisplayText><record><dates><pub-dates><date>Apr</date></pub-dates><year>1989</year></dates><keywords><keyword>Adipose Tissue/*metabolism/pathology</keyword><keyword>Adult</keyword><keyword>Aging/*metabolism</keyword><keyword>Body Composition</keyword><keyword>Body Height</keyword><keyword>Body Weight</keyword><keyword>Carbon Dioxide/metabolism</keyword><keyword>Child, Preschool</keyword><keyword>Energy Metabolism</keyword><keyword>Female</keyword><keyword>Glucose/metabolism</keyword><keyword>Humans</keyword><keyword>Infant</keyword><keyword>Male</keyword><keyword>Middle Aged</keyword><keyword>Obesity/*metabolism/pathology</keyword><keyword>*Oxygen Consumption</keyword><keyword>Triglycerides/metabolism</keyword><keyword>Weight Loss</keyword></keywords><isbn>0002-9513 (Print)&#xD;0002-9513</isbn><titles><title>Influence of age, fat cell weight, and obesity on O2 consumption of human adipose tissue</title><secondary-title>Am J Physiol</secondary-title><alt-title>The American journal of physiology</alt-title></titles><pages>E467-74</pages><number>4 Pt 1</number><contributors><authors><author>Hallgren, P.</author><author>Sjostrom, L.</author><author>Hedlund, H.</author><author>Lundell, L.</author><author>Olbe, L.</author></authors></contributors><edition>1989/04/01</edition><language>eng</language><added-date format="utc">1517490638</added-date><ref-type name="Journal Article">17</ref-type><auth-address>Department of Medicine, Sahlgren&apos;s Hospital, Goteborg, Sweden.</auth-address><remote-database-provider>NLM</remote-database-provider><rec-number>262</rec-number><last-updated-date format="utc">1517490638</last-updated-date><accession-num>2495730</accession-num><electronic-resource-num>10.1152/ajpendo.1989.256.4.E467</electronic-resource-num><volume>256</volume></record></Cite></EndNote>(Hallgren et al., 1989). In conclusion, values for VO2 calculated using two methods produced results which were not statistically significantly different from one another. However, VO2 values calculated using Sykes’ formula were more variable and unexpectedly higher than that calculated using Brody’s equation. Overall, O2 flows recommended for use in rebreathing systems appear to be in excess of requirements. Using the simple formula proposed by Sykes may enable lower flows to be used safely, minimising environmental pollution and cost.References ADDIN EN.REFLIST Aubier, M., Viires, N., Syllie, G., Mozes, R. and Roussos, C. (1982) 'Respiratory muscle contribution to lactic acidosis in low cardiac output', Am Rev Respir Dis, 126(4), pp. 648-52.Brody, S. (1945) 'Bioenergetics and growth: with special reference to the efficiency complex in domestic animals', Bioenergetics and growth: with special reference to the efficiency complex in domestic animals.Duke-Novakovski, T. (2016) BSAVA manual of canine and feline anaesthesia and analgesia. John Wiley & Sons.Hallgren, P., Sjostrom, L., Hedlund, H., Lundell, L. and Olbe, L. (1989) 'Influence of age, fat cell weight, and obesity on O2 consumption of human adipose tissue', Am J Physiol, 256(4 Pt 1), pp. E467-74.Haskins, S., Pascoe, P. J., Ilkiw, J. E., Fudge, J., Hopper, K. and Aldrich, J. (2005) 'Reference Cardiopulmonary Values in Normal Dogs', Comparative Medicine, 55(2), pp. 156-161.King, B. D., Harris, L. C., Jr., Greifenstein, F. E., Elder, J. D., Jr. and Dripps, R. D. (1951) 'Reflex circulatory responses to direct laryngoscopy and tracheal intubation performed during general anesthesia', Anesthesiology, 12(5), pp. 556-66.Laflamme, D. (1997) 'Development and validation of a body condition score system for dogs', Canine Pract., 22, pp. 10-15.Macbeth, R. A. L. and Bekesi, J. G. (1962) 'Oxygen Consumption and Anaerobic Glycolysis of Human Malignant and Normal Tissue', Cancer Research, 22(2), pp. 244.New Classification of Physical, s. (1963) 'American Society of Anaesthesiologists', Anaesthesiology, 24.Robinson, W. R., Peters, R. H. and Zimmermann, J. (1983) 'The effects of body size and temperature on metabolic rate of organisms', Canadian Journal of Zoology, 61(2), pp. 281-288.Rolly, G., Versichelen, L. and Moerman, E. (1984) 'Cardiovascular, metabolic and hormonal changes during isoflurane N2O anaesthesia', Eur J Anaesthesiol, 1(4), pp. 327-34.Sykes, O. (2010) 'Oxygen monitoring during low flow anaesthesia', Journal of Clinical Monitoring and Computing, 24(2), pp. 141-141.Tanaka, T. and Nangaku, M. (2010) 'The role of hypoxia, increased oxygen consumption, and hypoxia-inducible factor-1 alpha in progression of chronic kidney disease', Curr Opin Nephrol Hypertens, 19(1), pp. 43-50. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download