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| '''Blood gas tension''' refers to the [[partial pressure]] of gases in [[blood]].<ref name="pmid9563770">{{cite journal| author=Severinghaus JW, Astrup P, Murray JF| title=Blood gas analysis and critical care medicine. | journal=Am J Respir Crit Care Med | year= 1998 | volume= 157 | issue= 4 Pt 2 | pages= S114-22 | pmid=9563770 | doi= | pmc= | url= }}</ref> There are several significant purposes for measuring gas tension;<ref name="pmid16215371">{{cite journal| author=Bendjelid K, Schütz N, Stotz M, Gerard I, Suter PM, Romand JA| title=Transcutaneous PCO2 monitoring in critically ill adults: clinical evaluation of a new sensor. | journal=Crit Care Med | year= 2005 | volume= 33 | issue= 10 | pages= 2203–6 | pmid=16215371 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16215371 }}</ref> the most common gas tensions measured are oxygen tension<ref name="pmid14736638">{{cite journal| author=Yildizdaş D, Yapicioğlu H, Yilmaz HL, Sertdemir Y| title=Correlation of simultaneously obtained capillary, venous, and arterial blood gases of patients in a paediatric intensive care unit. | journal=Arch Dis Child | year= 2004 | volume= 89 | issue= 2 | pages= 176–80 | pmid=14736638 | doi= | pmc=1719810 | url= }}</ref> (P<sub>x</sub>O<sub>2</sub>), the carbon dioxide tension<ref name="pmid14736638"/> (P<sub>x</sub>CO<sub>2</sub>) and carbon monoxide tension<ref name="pmid14736638"/> (P<sub>x</sub>CO). The ''x'' factor in the symbol for each would be replaced by the source of the gas being measured; "''a''" meaning [[artery|arterial]],<ref name="pmid14736638"/> "''A''" being alveolar,<ref name="pmid14736638"/> "''v''" being [[vein|venous]],<ref name="pmid14736638"/> "''c''" being [[capillary]].<ref name="pmid14736638"/> | | I'm Jonelle and I live with my husband and our 3 children in Valley Trudde, in the south area. My hobbies are Nordic skating, Microscopy and LARPing.<br><br>Check out my web site; [http://tinyurl.com/l2yjyvf http://tinyurl.com/l2yjyvf] |
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| ==Oxygen tension==
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| ;Arterial blood oxygen tension (normal)
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| '''P<sub>a</sub>O<sub>2</sub>''' — Partial pressure of oxygen at sea level (765 mmHg) in arterial blood is between 75 mmHg and 100 mmHg.<ref name="pmid9390851">{{cite journal| author=Shapiro BA| title=Temperature correction of blood gas values. | journal=Respir Care Clin N Am | year= 1995 | volume= 1 | issue= 1 | pages= 69–76 | pmid=9390851 | doi= | pmc= | url= }}</ref><ref name="pmid17652681">{{cite journal| author=Malatesha G, Singh NK, Bharija A, Rehani B, Goel A| title=Comparison of arterial and venous pH, bicarbonate, PCO2 and PO2 in initial emergency department assessment. | journal=Emerg Med J | year= 2007 | volume= 24 | issue= 8 | pages= 569–71 | pmid=17652681 | doi=10.1136/emj.2007.046979 | pmc=2660085 }}</ref><ref name="pmid14569318">{{cite journal| author=Chu YC, Chen CZ, Lee CH, Chen CW, Chang HY, Hsiue TR| title=Prediction of arterial blood gas values from venous blood gas values in patients with acute respiratory failure receiving mechanical ventilation. | journal=J Formos Med Assoc | year= 2003 | volume= 102 | issue= 8 | pages= 539–43 | pmid=14569318 | doi= | pmc= | url= }}</ref>
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| ;Venous blood oxygen tension (normal) | |
| '''P<sub>v</sub>O<sub>2</sub>''' — Oxygen tension in venous blood at sea level is between 30 mmHg and 40 mmHg.<ref name="pmid14569318"/><ref name="pmid20018607">{{cite journal| author=Walkey AJ, Farber HW, O'Donnell C, Cabral H, Eagan JS, Philippides GJ| title=The accuracy of the central venous blood gas for acid-base monitoring. | journal=J Intensive Care Med | year= 2010 | volume= 25 | issue= 2 | pages= 104–10 | pmid=20018607 | doi=10.1177/0885066609356164 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20018607 }}</ref>
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| ==Carbon dioxide tension==
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| Carbon dioxide is a by-product of food metabolism and in high amounts has toxic effects including: [[dyspnea]], [[acidosis]] and [[altered consciousness]].<ref name="pmid2535633">{{cite journal| author=Adrogué HJ, Rashad MN, Gorin AB, Yacoub J, Madias NE| title=Assessing acid-base status in circulatory failure. Differences between arterial and central venous blood. | journal=N Engl J Med | year= 1989 | volume= 320 | issue= 20 | pages= 1312–6 | pmid=2535633 | doi=10.1056/NEJM198905183202004 | pmc= | url= }}</ref>
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| ;Arterial blood carbon dioxide tension
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| '''P<sub>a</sub>CO<sub>2</sub>''' — Partial pressure of carbon dioxide at sea level (765 mmHg) in arterial blood is between 35 mmHg and 45 mmHg.<ref name="pmid9794863">{{cite journal| author=Williams AJ| title=ABC of oxygen: assessing and interpreting arterial blood gases and acid-base balance. | journal=BMJ | year= 1998 | volume= 317 | issue= 7167 | pages= 1213–6 | pmid=9794863 | doi= | pmc=1114160 | url= }}</ref>
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| ;Venous blood carbon dioxide tension
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| '''P<sub>v</sub>CO<sub>2</sub>''' — Partial pressure of carbon dioxide at sea level in venous blood is between 40 mmHg and 50 mmHg.<ref name="pmid9794863"/>
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| ==Carbon Monoxide tension==
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| ;Arterial Carbon Monoxide tension (normal)
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| '''P<sub>a</sub>CO''' — Partial pressure of CO at sea level (765 mmHg) in arterial blood is approximately 0.02. It can be slightly higher in smokers and people living in dense urban areas.
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| ==Significance==
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| The partial pressure of gas in blood is significant because it is directly related to ventilation and oxygenation.<ref name="pmid2661120">{{cite journal| author=Hansen JE| title=Arterial blood gases. | journal=Clin Chest Med | year= 1989 | volume= 10 | issue= 2 | pages= 227–37 | pmid=2661120 | doi= | pmc= | url= }}</ref> When used alongside the pH balance of the blood the PaCO2 and HCO3 (and Lactate) lets the health care practitioner know what interventions need to be made, if any.<ref name="pmid2661120"/><ref name="pmid3144222">{{cite journal| author=Tobin MJ| title=Respiratory monitoring in the intensive care unit. | journal=Am Rev Respir Dis | year= 1988 | volume= 138 | issue= 6 | pages= 1625–42 | pmid=3144222 | doi= | pmc= | url= }}</ref>
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| == Equations ==
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| === Oxygen content ===
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| :<math>C_a O_2 = 1.36 * Hgb * \frac{S_a O_2}{100} + 0.0031 * P_a O_2</math> | |
| The constant, 1.36, is the amount of oxygen (ml at 1 atmosphere) bound per gram of hemoglobin. The exact value of this constant varies from 1.34 to 1.39, depending on the reference and the way it is derived. The constant 0.0031 represents the amount of oxygen dissolved in plasma. The dissolved oxygen term is generally small relative to the hemoglobin-bound oxygen, but becomes significant at very high PaO2 (as in a hyperbaric chamber) or in severe anemia.
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| === Oxygen saturation ===
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| :<math> SO_2 = (\frac{23,400}{pO_2^3 + 150 pO_2} +1)^{-1}</math>
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| This is an estimation and does not account for differences in temperature, pH and concentrations of 2,3 DPG.<ref>Severinghaus, J. W. Simple, accurate equations for human blood O2 dissociation computations. J Appl Physiol. 46(3): 599-602. 1979.</ref>
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| ==See also==
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| * [[Fick's laws of diffusion]]
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| * [[Alveolar air equation]]
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| ==References==
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| <references/>
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| [[Category:Hematology]]
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| [[Category:Respiratory therapy]]
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| [[Category:Pulmonology]]
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I'm Jonelle and I live with my husband and our 3 children in Valley Trudde, in the south area. My hobbies are Nordic skating, Microscopy and LARPing.
Check out my web site; http://tinyurl.com/l2yjyvf