Oximetry is the measurement of blood hemoglobin (Hb) saturations using spectrophotometry. Several types of Oximetry are used in clinical practice. The methods most commonly encountered in RT clinical practice include:

Hemoximetry (also called CO-oximetry) – performed in arterial blood gas analysis

Pulse Oximetry – portable, noninvasive monitoring technique
Pulse Oximetry

Pulse Oximetry provides estimates of arterial blood oxyhemoglobin saturation levels, but as not actual SaO2 measures. Therefore, pulse oximetry readings are recorded as SpO2. Supplemental oxygen should be “prescribed” to a target blood hemoglobin saturation according to the population served and clinical presentation (Kacmarek et al, 2013.)

Pulse oximetry can be performed at rest, exercise, and during activity. The Sp02 measured with the oximeter is widely used in clinical practice. Some refer to the oxygen saturation as the fifth vital sign. It is important to fully understand the appropriate applications and limitations of this technology.

Guidelines for pulse oximetry are available from the American Association of Respiratory Care (ARRC) at:

Key Points to Remember

Follow manufacturers protocol;
Always use compatible sensors;
Ensure correct type, size and fit of sensor;
Confirm adequacy and accuracy of reading (validate with ABG Sa02 when applicable);
Adjust alarm according to the clinical situation;
Apply standard precautions infection control;
Inspect and change sensor site as needed;
Never act on Sp02 alone, reading should reflect the patient’s clinical condition; and

Avoid using pulse oximetry to monitor hyperoxia in neonates.

This CBPG was not meant to be the last resource you will need to access to answer your clinical and professional practice questions. Alternatively, we have provided you with links to other important resources that you may need to access in order to obtain required information. Websites will change and we encourage you to let us know if you are unable to access any of the websites that we have connected you to. This is a “living document” and will have to adapt as the evidence and clinical best practice guidelines change.

We encourage all CRTO Members to be active in the ongoing development of this Oxygen Therapy CBPG and to continue to advocate for safe and ethical practices in your practice environment.


(ATP) Ambient Temperature and Pressure = (STP) standard temperature and pressure = 0C and 1 atmosphere

BTPS = Body Temperature and ambient Pressure Saturated = 37 °C, 1 atmosphere, and 44 mg H2O/L

Conserving Devices - How long liquid and cylinder systems last before refilling depends on the amount of oxygen a person uses. Conserving devices extend the length of time. Oxygen systems deliver oxygen continuously during inspiration and exhalation. Conserving devices can be programmed to deliver oxygen during inspiration only, therefore reducing the amount wasted during exhalation.

Cryogenic Vessel - A static or mobile vacuum insulated container designed to contain liquefied gas at extremely low temperatures. Mobile vessels could also be known as "Dewars". Retrieved from:

Drug Identification Number (DIN) - a computer-generated eight-digit number assigned by Health Canada to a drug product prior to being marketed in Canada. It uniquely identifies all drug products sold in a dosage form in Canada and is located on the label of prescription and over-the-counter drug products that have been evaluated and authorized for sale in Canada. A DIN uniquely identifies the following product characteristics: manufacturer; product name; active ingredient(s); strength(s) of active ingredient(s); pharmaceutical form; route of administration. Retrieved from:

Fractional Distillation - the process of separating the portions of a mixture by heating it and condensing the components according to their different boiling points. Retreived from:

Medical gas - (either a single gas or a mixture of gases) is a gas that requires no further processing in order to be administered, but is not in its final package (e.g., liquefied oxygen) and is known as a bulk gas. Retrieved from:

Manifold (rampe) - Equipment or apparatus designed to enable one or more medical gas containers to be filled at a time.


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  2. Becker, D. E., & Casabianca, A. B. (2009). Respiratory monitoring: physiological and technical considerations. Anesthesia Progress, 56(1), 14-20. doi: 10.2344/0003-3006-56.1.14.
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  4. Canadian Standards Association. (2016). Z305.12-06 (R2012) - Safe Storage, Handling, and Use of Portable Oxygen Systems in Residential Buildings and Health Care Facilities. Retrieved from:,%20Handling,%20and%20Use%20of%20Portable%20Oxygen%20Systems%20in%20Residential%20Buildings%20and%20Health%20Care
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  8. Mariciniuk, D. D., Goodridge, D., Hemandez, P., Rocker, J., Balter, M., Bailey, P., Brown, C. (2011). Managing dyspnea in patients with advanced chronic obstructive pulmonary disease: A Canadian Thoracic Society clinical practice guideline. Canadian Respiratory Journal, 18(2), 69–78. Retrieved from
  9. Ministry of Health and Long-Term Care. Policy and Procedures Manual for the Assistive Devices Program (May 2016). Conflict of Interest. Retrieved from: Policies and Procedures Manual of the Assistive Devices Program (
  10. O'Driscoll, B. R., Howard, L. S., Earis, J., & Mak, V. (2017). British Thoracic Society Guideline for oxygen use in adults in healthcare and emergency settings. BMJ open respiratory research, 4(1), e000170. Retrieved from:
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