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My Heartbeat and Peripheral Oxygen Saturation (SpO2)

My pulse rate is 79 to 80 beats per minute. 🌞

 

Baruch HaShem! !ברוך השם

Blessed is The Name!!

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SpO2 Defined as Peripheral Oxygen Saturation

incenter.medical.philips.com/doclib/enc/fetch/586262/5864...

 

Introduction

The body's need for oxygen is certain. Its availability at a tissue level is some- times in doubt. Blood gas measurements provide critical information regard- ing oxygenation, ventilation, and acid-base status.

However, these measurements only provide a snapshot of the patient's condition taken at the time that the blood sample was drawn. It is well known that oxygenation can change very quickly. In the absence of continuous oxygenation monitoring, these changes may go undetected until it is too late.

Pulse oximeters measure blood oxygen saturation noninvasively and continuously.

 

What is SpO2?

A blood-oxygen saturation reading indicates the percentage of hemoglobin molecules in the arterial blood which are saturated with oxygen. The reading may be referred to as SaO2. Readings vary from 0 to 100%. Normal readings in a healthy adult, however, range from 94% to 100%.

The term SpO2 means the SaO2 measurement determined by pulse oximetry. As explained in the section "Considerations When Using Pulse Oximetry," under some circumstances pulse oximetry gives different readings, and the use of a different term indicates this.

 

How Does Pulse Oximetry Work?

Within the Sp02 sensor, light emitting diodes shine red and infrared light through the tissue. Most sensors work on extremities such as a finger, toe or ear. The blood, tissue and bone at the application site absorb much of the light. However, some light passes through the extremity. A light-sensitive detector opposite the light source receives it.

 

SpO2 Sensors

Most sensors work on extremities such as a finger, toe or ear. The sensor measures the amount of red and infrared light received by the detector and calcu- lates the amount absorbed. Much of it is absorbed by tissue, bone and venous blood, but these amounts do not change dramatically over short periods of time.

The amount of arterial blood does change over short periods of time due to pulsation (although there is some constant level of arterial blood). Because the arterial blood is usually the only light absorbing component which is changing over short periods of time, it can be isolated from the other compo- cents.

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Oxygen Saturation As Presented in Wikipedia:

en.wikipedia.org/wiki/Oxygen_saturation_(medicine)

 

Oxygen saturation is a term referring to the fraction of oxygen-saturated hemoglobin relative to total hemoglobin (unsaturated + saturated) in the blood. The human body requires and regulates a very precise and specific balance of oxygen in the blood. Normal blood oxygen levels in humans are considered 95-100 percent. If the level is below 90 percent, it is considered low resulting in hypoxemia.[1] Blood oxygen levels below 80 percent may compromise organ function, such as the brain and heart, and should be promptly addressed. Continued low oxygen levels may lead to respiratory or cardiac arrest. Oxygen therapy may be used to assist in raising blood oxygen levels. Oxygenation occurs when oxygen molecules (O

2) enter the tissues of the body. For example, blood is oxygenated in the lungs, where oxygen molecules travel from the air and into the blood. Oxygenation is commonly used to refer to medical oxygen saturation.

 

Contents [hide]

1Definition

2Physiology

3Measurement

4Pulse oximetry

5Medical significance

6See also

7References

8External links

Definition[edit]

 

 

In medicine, oxygen saturation (SO2), commonly referred to as "sats," measures the percentage of hemoglobin binding sites in the bloodstream occupied by oxygen.[2] 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.

 

Physiology

The body maintains a stable level of oxygen saturation for the most part by chemical processes of aerobic metabolism associated with breathing. Using the respiratory system, red blood cells, specifically the hemoglobin, gather oxygen in the lungs and distribute it to the rest of the body. The needs of the body's blood oxygen may fluctuate such as during exercise when more oxygen is required [3] or when living at higher altitudes. A blood cell is said to be "saturated" when carrying a normal amount of oxygen.[4] Both too high and too low levels can have adverse effects on the body.

 

Measurement[edit]

 

An SaO2 (arterial oxygen saturation, as determined by an arterial blood gas test[5]) value below 90% causes hypoxemia (which can also be caused by anemia). Hypoxemia due to low SaO2 is indicated by cyanosis. Oxygen saturation can be measured in different tissues:

 

Venous oxygen saturation (SvO2) is measured to see how much oxygen the body consumes. Under clinical treatment, a SvO2 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 (extracorporeal circulation), and can give the perfusionist an idea of how much flow the patient needs to stay healthy.

Tissue oxygen saturation (StO2) can be measured by near infrared spectroscopy. Although the measurements are still widely discussed, they give an idea of tissue oxygenation in various conditions.

Peripheral oxygen saturation (SpO2) is an estimation of the oxygen saturation level usually measured with a pulse oximeter device. It can be calculated with pulse oximetry according to the following formula:

SpO2 = HbO2/ (HbO2 + Hb)

 

 

Example: Pulse Oximeter

Pulse oximetry is a method used to estimate the percentage of oxygen bound to hemoglobin in the blood. This approximation to SaO2 is designated SpO2 (peripheral oxygen saturation). The pulse oximeter consists of a small device that clips to the body (typically a finger, earlobe or an infants foot) and transfers its readings to a reading meter by wire or wirelessly. The device uses light-emitting diodes in conjunction with a light-sensitive sensor to measure the absorption of red and infrared light in the extremity. The difference in absorption between oxygenated and deoxygenated hemoglobin makes the calculation possible.[5]

 

Medical significance

Effects of decreased oxygen saturation[6]

SaO2Effect

85% and aboveNo evidence of impairment

65% and lessImpaired mental function on average

55% and lessLoss of consciousness on average

Healthy individuals at sea level usually exhibit oxygen saturation values between 96% and 99%, and should be above 94%. At 1600 meters altitude (about one mile high) oxygen saturation should be above 92%.[7]

 

An SaO2 (arterial oxygen saturation) value below 90% causes hypoxia (which can also be caused by anemia). Hypoxia due to low SaO2 is indicated by cyanosis, but oxygen saturation does not directly reflect tissue oxygenation. The affinity of hemoglobin to oxygen may impair or enhance oxygen release at the tissue level. Oxygen is more readily released to the tissues (i.e., hemoglobin has a lower affinity for oxygen) when pH is decreased, body temperature is increased, arterial partial pressure of carbon dioxide (PaCO2) is increased, and 2,3-DPG levels (a byproduct of glucose metabolism also found in stored blood products) are increased. When the hemoglobin has greater affinity for oxygen, less is available to the tissues. Conditions such as increased pH, decreased temperature, decreased PaCO2, and decreased 2,3-DPG will increase oxygen binding to the hemoglobin and limit its release to the tissue.[8]

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Uploaded on October 10, 2016
Taken on October 10, 2016