Oxygen saturation 1096360 220971047 2008-06-22T13:29:10Z DOI bot 6652755 Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. '''Oxygen saturation''' is a relative measure of the amount of [[oxygen]] that is [[dissolve]]d or carried in a given medium. It can be measured with a dissolved oxygen probe such as an [[oxygen sensor]] or an [[optode]] in liquid media, usually water. ==Medical science== In [[medicine]], '''oxygen saturation''' (S<sub>O<sub>2</sub></sub>), commonly abbreviated as "sats", measures the percentage of [[hemoglobin]] binding sites in the bloodstream occupied by oxygen. At low partial pressures of oxygen, most hemoglobin is deoxygenated. At around 90% (the value varies according to the clinical context) oxygen saturation increases according to an [[oxygen-hemoglobin dissociation curve]] and approaches 100% at partial oxygen pressures of >10 kPa. A [[pulse oximeter]] relies on the light absorption characteristics of saturated hemoglobin to give an indication of oxygen saturation. An Sa<sub>O<sub>2</sub></sub> (arterial oxygen saturation) value below 90% is termed [[hypoxemia]]. This may be due to various medical conditions. The Sv<sub>O<sub>2</sub></sub> (venous oxygen saturation) is measured to see how much oxygen the body consumes. Under clinical treatment, a Sv<sub>O<sub>2</sub></sub> below 60%, indicates that the body is in lack of oxygen, and ischemic diseases occur. This measurement is often used under treatment with a heart-lung machine (Extra Corporal Circulation), and can give the perfusionist an idea of how much flow the patient needs to stay healthy. Tissue [[oxygen]] saturation (St<sub>O<sub>2</sub></sub>) can be measured by [[near infrared spectroscopy]]. Although the measurements are still widely discussed, they give an idea of tissue oxygenation in various conditions. Saturation of Peripheral Oxygen (Sp<sub>O<sub>2</sub></sub>) is an estimation of the oxygen saturation level usually measured with a [[pulse oximeter]] device. == Environmental sciences == [[Image:AYool WOA surf O2.png|thumb|right|Annual mean sea surface dissolved '''oxygen''' for the [[World Ocean]]. Data from the [[World Ocean Atlas]] [http://www.nodc.noaa.gov/OC5/WOA01/ 2001].]] [[Image:AYool WOA AOU 180E.png|thumb|right|[[Pacific Ocean]] sections of dissolved oxygen and [[apparent oxygen utilisation]]. Data from the [[World Ocean Atlas]] [http://www.nodc.noaa.gov/OC5/WOA05/pr_woa05.html 2005].]] In [[water|aquatic]] environments, '''oxygen saturation''' is a relative measure of the amount of [[oxygen]] (O<sub><small>2</small></sub>) dissolved in the water. Supersaturation can sometimes be harmful for organisms and cause decompression sickness. '''Dissolved oxygen''' ('''DO''') is measured in standard solution units such as millilitres O<sub>2</sub> per litre (ml/L), millimoles O<sub><small>2</small></sub> per litre (mmol/L), milligrams O<sub><small>2</small></sub> per litre (mg/L) and moles O<sub>2</sub> m<small>3</small>. For example, in freshwater under atmospheric pressure at 20°C, O<sub>2</sub> saturation is 9.1 mg/L. Solubility tables (based upon temperature) and corrections for different salinities and pressures can be found at the [http://water.usgs.gov/owq/FieldManual/Chapter6/6.2.4.pdf USGS web site]. Tables such as these of ''DO'' in milliliters per liter (ml/L) are based upon empirical equations that have been worked out and tested (e.g. Weiss, 1970): <center> <math>ln(DO) = A1 + A2*100/T + A3*ln(T/100) + A4*T/100 + S*[B1 + B2*T/100 + B3*(T/100)^2]</math> </center> Where ''ln'' is the [[natural log]] and the other variables take the following values: <center> {| |- | ''A1'' | = | -173.4292 | | ''B1'' | = | -0.033096 |- | ''A2'' | = | 249.6339 | | ''B2'' | = | 0.014259 |- | ''A3'' | = | 143.3483 | | ''B3'' | = | -0.001700 |- | ''A4'' | = | -21.8492 |- | ''T'' | = | temperature ([[kelvin]]s) | | ''S'' | = | salinity (g/kg) |} </center> To convert the calculated ''DO'' above from ml/L to mg/L, multiply the answer by 1.4276. ==See also== * [[Pulse oximetry]] * [[Apparent oxygen utilisation]] * [[Arterial blood gas]] * [[Wastewater quality indicators]] discusses both [[Biochemical oxygen demand|BOD]] and [[Chemical oxygen demand|COD]] as indicators of wastewater quality. ==References== * {{cite journal |author=Weiss, R. |title=The solubility of nitrogen, oxygen, and argon in water and seawater |journal=Deep-Sea Res. |date=1970 |volume=17 |issue= |pages=721–35}} * [http://www.altitude.org/calculators/saturationgraph/saturationgraph.htm Interactive haemoglobin saturation graph] ==External links== [[Category:Aquatic ecology]] [[Category:Blood]] [[Category:Water quality indicators]] [[Category:Oxygen]] [[da:Iltmætning]] [[de:Sauerstoffsättigung]] [[ko:포화 산소량]] [[ja:溶存酸素量]] [[pl:Saturacja (medycyna)]] [[fi:Happisaturaatio]]