Does your oximeter work for all of your patients? How can you know?
COPD PATIENTS OFTEN PRESENT WITH COMPLEX CO-MORBIDITIES
PULSE WAVE DISTORTIONS CAN CAUSE INNACCURATE OXIMETER READINGS2
When a COPD patient is desaturating, the following may be present:
- Low pulse strength – poor blood circulation can result in low pulse strength. Cold hands from a variety of reasons/conditions can also result in low pulse strength.
- Little or no oxygen reserve – COPD patients have little or no oxygen reserve capacity in their lungs and can be living on the edge of hypoxemia.3
- Labored breathing – dyspnea can cause labored breathing and chest heaving, which can create pulse wave distortions.
As a result… it becomes harder for the oximeter to find the true pulse, particularly when the patient’s oxygen level is dropping.
Which oximeters are accurate in tracking desaturations?
Follow Nonin Medical’s invention of the fingertip oximeter in 1995 there has been a proliferation of brands introduced.
MANY OF THE NEW OXIMETERS ARE MADE BY TWO MANUFACTURERS2
- Beijing Choice Electronic Technology Co Ltd. (Beijing, China)
- Contec Medical Systems Co Ltd. (Qinhuangdao, China)
These two companies make over 30 different oximeter brands and models2 – major retailer brands, distributor brands, and internet brands. Some are FDA-cleared while some are “health and wellness” devices.
CURRENT ACCURACY ASSESSMENT METHODS CAN BE FLAWED
- Often clinicians assess an oximeter by comparing the oximeter to a tabletop or multi-parameter oximeter using a healthy individual or a COPD patient who is in stable condition.
- Accuracy assessment is most relevant when done on a COPD patient who is desaturating with associated labored breathing (dyspnea) and low pulse strength.
WHITE PAPER SUMMARY
Fingertip Pulse Oximeter Performance in Dyspnea and Low Perfusion During Hypoxic Events
P.B. Batchelder, RRT, LRCP, Clinimark Laboratories, Boulder, Colorado
CLINIMARK, LLC – CLINICAL TESTING AND VALIDATION SERVICES FOR MEDICAL DEVICES
Clinimark is an independent laboratory whose purpose is to provide impartial research and clinical laboratory testing for medical device development and FDA regulatory validation in invasive and non-invasive monitoring intended for the medical setting. Clinimark is actively involved with standards organizations, such as the ASTM, ISO, and IEC, working with the FDA in development of worldwide harmonized pulse oximetry standards.
OXIMETER PERFORMANCE COMPARISON
Clinimark conducted a test on human subjects in which they induced the conditions typical of a COPD patient with low pulse strength, dyspnea, experiencing a desaturation, or hypoxic event. They then tested devices from three manufacturers to see which ones could track the hypoxic event.
TEST METHODOLOGY
- An arm of each subject was cooled with cold air to reduce blood circulation and create a low pulse strength condition.
- Multiple desaturation events were induced along with dyspnea (labored breathing).
- A Nonin oximeter along with a Beijing Choice or Contec Medical fingertip pulse oximeter and a reference device were placed on the test hand.
- A Nellcor N600x tabletop oximeter was used as the reference device.
FIGURE 1: Example of Frozen Reading
The green reference pulse oximeter shows a hypoxic event. The purple pulse oximeter tracked the event. The blue oximeter was frozen.
Figure 2: Example of No Tracking
The green reference pulse oximeter shows a hypoxic event. The purple pulse oximeter tracked the event. The blue pulse oximeter was >10% inaccurate.
Only the Nonin oximeter, with PureSAT technology, was able to accurately track desaturations in humans with low pulse strength and labored breathing.
RESULTS
The charts below show the percentage of subjects in which oxygen level changes were accurately tracked.
- The oximeters made by Beijing Choice and Contec Medical failed to track many of the desaturations.
- These two companies make many of the oximeter brands sold by retailers, internet sellers and distributors.
Trust Nonin Oximeter, even for your sickest patients.
Your oximeter needs to work on all your patients, especially the sickest. Only Nonin makes Nonin.
REFERENCES
- PHC4-provided hospital discharges between October 1, 2007 and September 30, 2008. Pittsburgh Regional Health Initiative 2010.
- Mechanisms of Disease: Congestive Heart Failure. Loyola University Medical Education Network. http://www.meddean.luc.edu/lumen/meded/mech/cases/case4/chf.htm
- Nonin Medical, Inc. Data on file.
- Batchelder, P.B., Fingertip Pulse Oximeter Performance in Dyspnea and Low Perfusion During Hypoxic Events. Clinimark Laboratories, Boulder, Colorado. 2016. White Paper.