School of Health Sciences and Welfare, Helen McArdle Institute of Nursing and Nursing, University of Sunderland, Sunderland, UK
Nicholas Harland, School of Health Sciences and Welfare, Helen McArdle Institute of Nursing and Nursing, University of Sunderland City Campus, Chester Road, Sunderland SR1 3SD, UK.
School of Health Sciences and Welfare, Helen McArdle Institute of Nursing and Nursing, University of Sunderland, Sunderland, UK
Nicholas Harland, School of Health Sciences and Welfare, Helen McArdle Institute of Nursing and Nursing, University of Sunderland City Campus, Chester Road, Sunderland SR1 3SD, UK.
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The COVID-19 Oximetry@Home service has been activated nationwide. This allows high-risk patients with mild COVID-19 symptoms to stay at home and obtain a pulse oximeter to measure their oxygen saturation (SpO2) 2 to 3 times a day for two weeks. Patients record their readings manually or electronically and are monitored by the clinical team. The clinical decision to use the algorithm is based on SpO2 readings within a narrow range, where 1-2 point changes may affect care. In this article, we discussed multiple factors affecting SpO2 readings, and some “normal” individuals will have a “low normal” score at the clinical management threshold without any known breathing problems. We discussed the potential severity of this problem based on relevant literature, and considered how this will affect the use of the Oximetry@home service, which may partially confuse its purpose; reduce face-to-face medical treatment.
There are many advantages to managing less severe COVID-19 cases in the community, although this restricts the use of medical equipment such as thermometers, stethoscopes, and pulse oximeters during the evaluation. However, since the patient’s pulse oximetry measurement at home is useful in preventing unnecessary emergency department visits (Torjesen, 2020) and early identification of asymptomatic hypoxia, however, NHS England recommends that the whole country Entrust the “Spo2imetry@Home” service (NHSE, 2020a)) For patients with mild COVID-19 symptoms but a higher risk of deterioration, a pulse oximeter can be used for 14 days of treatment, in order to 2-3 times a day Self-monitoring of its oxygen saturation (SpO2).
Patients referred to the Oximetry@Home service are usually directed to use an app or paper diary to record their observations. The app either provides automatic responses/recommendations, or the clinician monitors the data. If necessary, the clinician can contact the patient, but usually only during normal working hours. Patients are told how to interpret their results so that they can act independently when needed, such as seeking emergency care. Due to the higher risk of worsening the disease, people over 65 years of age and/or with multiple comorbidities who are defined as extremely vulnerable are becoming the target of this approach (NHSE, 2020a).
The evaluation of patients in the Oximetry@Home service is first to measure their oxygen saturation through the pulse oximeter SpO2, and then to consider other signs and symptoms. Using red, amber, and green (RAG) ratings, if a patient’s SpO2 is 92% or lower, the patient is classified as red, and if their SpO2 is 93% or 94%, they are classified as amber, if If their SpO2 is 95% or higher, they are classified as green. Generally, only green patients are eligible to use Oximetry@Home (NHSE, 2020b). However, various non-disease-related factors can affect the SpO2 score, and these factors may not be considered in the pathway. In this article, we discussed the various factors affecting SpO2 that may affect patients’ access to Oximetry@Home services. These factors may partially confuse its purpose of reducing the pressure of face-to-face medical services.
The acceptable range of “normal” blood oxygen saturation measured by a pulse oximeter (SpO2) is 95%-99%. Despite the existence of documents such as the World Health Organization Pulse Oximetry Training Manual (WHO, 2011), the statement is so ubiquitous that medical articles rarely cite it. When searching for regulatory data on SpO2 in non-medical populations, little information is found. In a study of 791 people 65 years and older (Rodríguez-Molinero et al., 2013), after considering variables such as COPD, the average 5% SpO2 score was 92%, indicating a 5% measurement The blood oxygen saturation of the population is significantly lower than that without any known medical explanation. In another study of 458 individuals aged 40-79 (Enright & Sherrill, 1998), the oxygen saturation range before the 6-minute walk test was 92%-98% in the 5th percentile, and in the 95th percentile. The first percentile is 93%-99% percentile. Both studies did not document the procedures used to measure SpO2 in detail.
A population study of 5,152 people in Norway (Vold et al., 2015) found that 11.5% of people had SpO2 below or equal to the 95% low or lower limit of normal. In this study, only a small number of individuals with low SpO2 were reported to have asthma (18%) or COPD (13%), while a statistically significant majority of individuals had a BMI of more than 25 (77%), and a large proportion Are 70 years of age or older (46%). In the United Kingdom, 24.4% of the cases tested for COVID-19 between May and August 2020 were 60 years or older, and 15% were 70 years or older[8] (Ministry of Health and Social Care, 2020). Although the Norwegian study shows that 11.5% of any population may have a low SpO2, and most of these cases have no known respiratory diagnosis, the literature indicates that there may be “millions” of undiagnosed COPD (Bakerly & Cardwell, 2016). ) And potentially high rates of undiagnosed obesity hypoventilation syndromes (Masa et al., 2019). A statistically significant proportion of unexplained “low normal” SpO2 scores found in population studies may have undiagnosed respiratory diseases.
In addition to the overall variance, specific factors of the protocol used to measure SpO2 may affect the results. There is a statistically significant difference between the measurement taken at rest and the measurement taken while sitting (Ceylan et al., 2015). In addition, as well as age and obesity factors, SpO2 may decrease within 5-15 minutes of rest (Mehta and Parmar, 2017), more specifically during meditation (Bernardi et al., 2017). Limb temperature related to ambient temperature may also have a statistically significant effect (Khan et al., 2015), as is anxiety, and the presence of anxiety may reduce scores by a full point (Ardaa et al., 2020). Finally, it is well known that the standard error of pulse oximeter measurement is ± 2% compared with the synchronized arterial blood gas measurement SaO2 (American Thoracic Society, 2018), but from a clinical point of view, from a practical point of view, Because there is no way to account for this difference, it is necessary to measure and act on the face value.
Changes in SpO2 over time and repeated measurements are another problem, and there is very little information about this in the non-medical population. A small sample size (n = 36) study examined SpO2 changes within one hour [16] (Bhogal & Mani, 2017), but did not report variability during repeated measurements over several weeks, as in Oximetry@ During Home.
During the 14-day Oximetry@Home monitoring period, SpO2 was measured 3 times a day, which may be more frequent for anxious patients, and 42 measurements can be taken. Even assuming that the same measurement protocol is used in each case and the clinical condition is stable, there is reason to believe that there are certain differences in these measurements. Population studies using one measurement indicate that 11.5% of people’s SpO2 may be 95% or lower. Over time, in compliance with COVID-19, over time, one time or It is suggested that the possibility of multiple low readings may be higher than 11.5%.
The algorithm behind the Oximetry@Home service suggests that poor results are associated with lower SpO2 scores [17] (Shah et al., 2020); those with SpO2 falling to 93% to 94% should undergo face-to-face medical evaluation and be considered for admission, 92 % And below should receive emergency secondary medical care. With the implementation of the Oximetry@Home service nationwide, repeated SpO2 measurements taken by patients at home will become an important factor in explaining their clinical conditions.
SpO2 measurement is most often performed within a short period of time when the oximeter is placed. The patient sits and does not rest for a period of time. Walking from the waiting area to the clinical area, the rest will be physically interrupted. With the activation of the Oximetry@Home service, the NHS YouTube video (2020) has been released. The video recommends that patients taking measurements at home lie down for 5 minutes, place the oximeter, and then get the most stable reading 1 minute after placement. This video link has been circulated through the future NHS collaboration platform page related to the person setting up the Oximetry@Home service, but it does not seem to indicate that this may provide lower readings compared to the readings taken while sitting. It is worth noting that another NHS health education video in England in the Daily Mail newspaper recommends a completely different protocol, which is to read while sitting (Daily Mail, 2020) .
In a generally unknown individual, a low score of 95%, even a drop of 1 point due to COVID-19 infection may result in an Amber rating, leading to direct clinical care. What is unclear is whether a single point of decline will make direct clinical care an effective use of resources among individuals with low pre-morbid scores.
Although the national algorithm also mentions the SpO2 drop, since the vast majority of cases did not record the pre-disease SpO2 score, this factor cannot be assessed before any initial drop caused by the virus that caused the SpO2 assessment. From a decision-making perspective, it is clinically unclear whether an individual’s optimal saturation/perfusion level while sitting should be used as the baseline for tissue care, or whether the reduced saturation/perfusion level when lying down after a rest should be used as the baseline. There does not seem to be a policy agreed to by the country on this.
SpO2% is a compelling publicly available parameter for evaluating COVID-19. NHS England has purchased 370,000 oximeters for use by multiple patients for distribution to services.
The factors described may cause many single-point SpO2 measurement changes, triggering face-to-face patient reviews in primary care or emergency departments. Over time, thousands of patients in the community may be monitored for SpO2, which may lead to a large number of unnecessary face-to-face reviews. When the impact of factors affecting SpO2 readings in COVID-19 cases is analyzed and placed in the context of population-based clinical and household measurements, the potential impact is statistically significant, especially for those “missing millions”. There may be a critical SpO2. In addition, the Oximetry@Home service is more likely to select people with a cut-off score by targeting people over 65 and those who may have a higher BMI associated with comorbidities. Studies have shown that the “low normal” population will account for at least 11.5% of all individuals, but due to the selection criteria of the Oximetry@Home service, this percentage seems to be much higher.
Since the factors that have been documented to influence SpO2 scores are at work, patients with generally lower scores, especially those with 95% scores, may move between the green and amber ratings multiple times. This action may even occur between the routine clinical practice measurement when the referral to Oximetry@Home and the first measurement when the patient uses the 6-minute lying down protocol at home. If the patient feels unwell, the anxiety during the measurement may also reduce those with a cut-off score below 95% and seek care. This may result in multiple unnecessary face-to-face care, putting additional pressure on services that have reached or exceeded capacity.
Even in addition to commissioning the Oximetry@Home route and providing patients with medical supplies of oximeters, news reports on the usefulness of pulse oximeters are widespread, but it is not known how many people may have pulse oximeters in response to COVID- The 19 pandemic, although there are many different vendors offering relatively cheap equipment and reports of equipment sold out (CNN, 2020), this number may be at least hundreds of thousands. The factors described in this article may also affect these people and put further pressure on the service.
We declare that each of the authors listed has made a substantial contribution to the production of this article, and contributed to the ideas and written content.
Due to the approval of the literature analysis and research ethics committee, it is not applicable to this article submission.
Data sharing does not apply to this article because no data sets were generated or analyzed during the current research period.
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Post time: Jul-09-2021