Co-oximeter

by Chris Nickson, Last updated April 27, 2016

USES

measurement of blood concentration of various forms of haemoglobin

DESCRIPTION

a device that uses spectrophotometry to measure relative blood concentrations of oxyhemoglobin, carboxyhemoglobin, methemoglobin, and reduced haemoglobin

METHOD OF INSERTION AND/OR USE

a laboratory test involving a blood sample heated to 37 C and subjected to light of various length and assesses absorption spectra.
does not require pulsatile flow
measures MetHb, COHb and other forms of Hb
uses many other wavelengths

OTHER INFORMATION

measures either venous, arterial or capillary oxygenation

COMPLICATIONS

Causes of HIGH Co-oximetery and LOW Pulse Oximetry Readings

Poor peripheral perfusion
Ambient light
Poor probe contact
Dyes (e.g. methylene blue)
Tricuspid regurgitation (and other causes of venous pulsations)

Causes of LOW Co-oximetry and HIGH Pulse Oximetry Readings

COHb
MetHb
Radiofrequency interference
Leukocyte larceny (oxygen consumption by cells in the collection tube, may also occur in situations such as severe thrombocytosis)

References and links

FOAM and Web resources

About Chris Nickson

FCICM FACEM BSc(Hons) BHB MBChB MClinEpid(ClinTox) DipPaeds DTM&H GCertClinSim

Chris is an Intensivist at the Alfred ICU in Melbourne and is an Adjunct Clinical Associate Professor at Monash University. He is also the Innovation Lead for the Australian Centre for Health Innovation and the Chair of the Australian and New Zealand Intensive Care Society (ANZICS) Education Committee. He has a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia's Northern Territory, Perth and Melbourne. He has since completed further training in emergency medicine, clinical toxicology, clinical epidemiology and health professional education. He coordinates the Alfred ICU's education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the 'Critically Ill Airway' course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of Lifeinthefastlane.com, the RAGE podcast, the Resuscitology course, and the SMACC conference. His one great achievement is being the father of two amazing children. On Twitter, he is @precordialthump.

Comments

Malini says

April 27, 2016 at 6:54 am

what does TR stand for?

Reply

Leave a Reply Cancel reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

×