In response to the onslaught of the fifth wave of COVID-19 and the soaring number of confirmed cases, many patients are required to self-quarantine at home. Some patients may purchase their own fingertip pulse oximeter to monitor their blood oxygen level, so as to observe whether their health condition has deteriorated or whether medical attention is needed. Nevertheless, as some fingertip pulse oximeters on the market, especially the non-medical use ones that may not have been reviewed by medical regulatory authorities, the product quality may not be guaranteed. Besides, the accuracy of their readings could easily be affected by different factors. If consumers fail to use them correctly, they may misjudge their health condition or even lead to delay in seeking treatment. At present, there is no specific legislation in Hong Kong to regulate medical devices such as fingertip pulse oximeters. The Consumer Council urges the Government to introduce regulations to ensure the quality of these medical devices to safeguard consumer rights.
Oximeters are non-invasive devices that measure the oxygen saturation of haemoglobin of peripheral capillaries (SpO2). It is usually worn on the part of the user with more capillaries, for instance, fingers or toes. After completing each measurement, the oximeter will display two sets of numbers, namely the SpO2 and pulse rate. Medical oximeters are used for monitoring the blood oxygen level and pulse and their accuracy should have been confirmed by clinical tests. As for non-medical oximeters, they are more commonly used for recording the blood oxygen level during exercise. However, as non-medical oximeters may not have been reviewed by medical regulatory authorities, the respective reading should only be taken for reference or for non-medical use. This April, the Council reviewed fingertip pulse oximeters on the market with retail prices ranging from $85 to over $2,000, a difference of over 22 times.
Accuracy of Oximeters Affected by Multiple Factors
The Council reminds consumers that the blood oxygen level displayed on the fingertip pulse oximeter is only one of the reference indicators in monitoring health conditions. The reading could be affected by many factors, and discrepancies might even occur. The condition of the fingers, cold and clammy hands, overly long fingernails or shaky hands, environmental conditions, and measuring techniques could all affect the accuracy of the oximeter. Therefore, patients cannot rely solely on the reading of oximeters as health indicators, nor should the readings be used to substitute for the importance of examining clinical symptoms or observations. In addition, the SpO2 reading for healthy people should be in the range of 95% to 100%, with a pulse rate of 60 to 100 times per minute. However, if the patient is suffering from diseases that affect breathing, such as chronic obstructive pulmonary disease and pulmonary fibrosis, having a measured reading below 95% might not be related to hypoxia from COVID-19 infection. Besides, as the current mainstream Omicron variant is relatively less likely to cause pneumonia, consumers should not rely solely on oximeter readings to determine the need to seek medical attention. If patients experience other serious symptoms, such as persistent fever, difficulty breathing or shortness of breath, chest pain, lips turning blue, or pale complexion, they should see a doctor even if the oximeter shows a SpO2 of 95% or above.
Post-pandemic Surge in Consumer Demand for Medical Devices
Establish Legislation to Enhance Safeguard
Due to the pandemic, many families may purchase oximeters as a safeguard at home. Currently, there is no specific legislation regulating medical devices in Hong Kong. The Department of Health (DH) started to implement the voluntary “Medical Device Administrative Control System (MDACS)” in 2004 which lists the products that meet the requirements in terms of safety, quality, and performance, and there are currently over 20 models of oximeters on the list. However, the Council found that the name of 1 model in a retail store, which was marked with the HKMD Number of the DH’s Medical Device Division, was actually inconsistent with the product name listed on the DH’s official website, while only the company name of the local responsible person was found to match. The relevant product information has been forwarded to the DH for follow-up. The Council stressed that given the voluntary MDACS has been adopted for almost 20 years, it is time to impose tighter regulations in safeguarding the quality of medical devices. In Europe, oximeters for clinical diagnostic use are considered medical devices bound by regulations, requiring manufacturers to display valid compliance markings on packaging and devices, and report serious incidents involving their medical use.
Read Manuals Carefully to Master Usage Techniques
Fingertip pulse oximeters may seem convenient and easy to use. However, if consumers neglect their limitations and usage techniques or do not follow the instructions, it may lead to inaccurate readings. Therefore, consumers should pay heed to the following points when using them:
- After purchasing an oximeter, measure the blood oxygen level several times when the user is in a physically fit and stable condition. These measurements serve as a monitoring benchmark for testing the blood oxygen status for future comparisons, so as to determine whether blood oxygen remains at a normal level;
- Monitoring focuses on observing the trend rather than a single reading. If the reading shows a downward trend for a period of time, the user should pay attention to any possible health issues;
- Talking while measuring or having shaky hands might affect the results. If both hands shake severely, it is recommended to use toes for measurement. However, the pulse of toes is weaker, and the accuracy of the reading may be lower;
- It is not advisable to measure both blood pressure and blood oxygen of the same hand at the same time, because the armband of the sphygmomanometer will inflate and tighten on the arm, which will affect the blood flow. If the fingertip on the same side is used to measure blood oxygen, the reading may be affected;
- When measuring, it is best to use a suitable finger according to the instructions in the manual. The finger should be suitably sized. Fingernails that are too long or painted, and hands that are too cold or clammy, may affect the reading;
- First understand which age group the oximeter model is designed for, especially when used on children. If the device is too loose and unstable after clipping on the finger, it may increase the chance of reading error;
- The measurement environment should not be too bright, so as not to affect the light collected by the probe;
- Oximeters might not be suitable for patients with arrhythmia or atrial fibrillation;
- Consumers should follow the oximeter manufacturer’s product instructions in cleaning and using the medical device correctly. If an issue with the oximeter occurs, stop using it and enquire with the manufacturer or agent. Do not disassemble and repair it yourself.
Download the article (Chinese only): https://ccchoice.org/548oximeter
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