Innovative Appendix-Oxygen Saturation Measurement.
This appendix lists innovative ideas/pilots from across General Practice to give examples of the opportunities that exist to deliver care differently.
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Oxygen saturation probe work for remote Covid-19 monitoring and how to move equipment safely around your community for remote monitoring
Following the recommendation that the ROTH score is not used in primary care and the University of Oxford findings that smartapps cannot be reliably used as indicators of hypoxia in the Covid-19 pandemic, this document sets out the background to monitoring and the steps GPs can take to assess patients remotely with some ideas about how oxygen saturations could be performed dependent on setting.
Which patients could this apply to?
- Direct patient contact with a GP practice or “hot-hub” with COVID-19 symptoms
- Patients directed to primary care from the CCAS service (which require monitoring)
- Patients discharged from secondary care services perhaps not meeting admission threshold criteria
- Recovering Covid positive patients in the community
What new evidence has emerged about saturation monitoring?
A rapid systematic review(1) was undertaken to review the efficacy and safety of exertional desaturation tests in Covid-19. This is was performed as it is becoming clear that some patients have normal pulse oximetry at rest but their readings deteriorate on exertion (unpublished data).
Indeed, front-line clinicians have identified the late transfer of patients with exertional desaturation (i.e. a fall of 3% or more in pulse oximetry reading on exercise) as a possibly remediable cause of poor outcome. In other words, if we could better identify those with exertional desaturation and escalate their care more promptly, we could reduce mortality. (1)
Two tests have potential: the 1-minute sit-to-stand test (in which the patient goes from sit to stand as many times as they can in one minute) and the 40-step test (in which the patient takes 40 steps on a flat surface). The former correlates well with the validated 6-minute exercise test. The latter is less demanding (hence safer) and in more widespread use, but does not appear to have been validated. (1)
Conclusion: There is no evidence of harm (e.g. precipitation of cardiopulmonary compromise) from either test, but neither is there firm confirmation of their safety. Neither test has been studied in the context of covid-19; they were validated on patients with chronic interstitial lung disease and airways obstruction. An exertional desaturation test should be used with clinical judgement, and only on patients whose resting oximetry reading is 96% or above unless they are in a supervised care setting. It should be terminated if the patient experiences adverse effects. (1)
What benefits might an oxygen saturation assessment in addition to a remote consultation provide?
- Objective measure of deterioration (protection for GPs that an “adequate” assessment has been performed) and reassurance for patient.
- Key factor in admission and severity assessment, preventing unneeded admission/contact with high risk areas for the patient
- Allow a desaturation assessment
- Predict which patients might be at greatest risk, especially highlighting the seemingly well but silent hypoxic patients (unknown but aspirational aims might be noticing earlier deterioration for a potential improved outcome).
What models of care have been used elsewhere?
It is important to remember that these are new models of care delivery, with little known about the effectiveness/outcomes and are based upon many factors which need to be considered at a local level.
- “Drive-by" assessments face to face after being triaged - asking patients to come for ‘in-car’ assessments (pulse oximeter through window, respiratory rate, ‘eye-ball’ assessment). Variations of this are a “monitoring bay” (attend a hub, but not a full assessment)
- “On-site”-making ‘in-hub’ or GP face-to-face consultations as brief as possible
- “Vital signs visiting service”: collecting vital observations (pulse oximetry) - perhaps only ‘at-door’ oximetry without entering dwelling. Video link for history, RR, HR etc. This is the model in South West London (with 2 volunteer cars, collecting after each assessment)
- “Patient led” service (e.g. home delivery of oxygen saturation probes, which patient keeps for the duration of the illness or the “risk time” or are collected/returned after the assessment as part of a visiting team (or mobile family, friends or volunteers)
- Harrow HOMS and Barnet volunteers service are assisting with a home loaning system.
- The North West London collaboration are also trialling home loaning of saturation probes and patients uploading the recorded saturations onto an online app (MEDOPAD). This app clinically scores the risk features and prioritises the calls at the hot hub, calculating which patients have clinical features which are worsening.
- A Londonwide response has been developed using a hotline number.
Factors to consider:
- Demand: This might be rapidly changing, affecting the model of care. High volume performed by drive-by assessment, compared to low volume of cases managed through a “patient-led” approach.
- Geography of the practice population. Urban/rural practices have different challenges. Are rural outlining patients challenging? Visit time to patients? How the locality has set up their care delivery
- Physical site: Does the site allow traffic flow and parking?
- Access to the equipment (saturation probes, PPE, human resource/volunteer network)
- Patient factors: patient or carer must be willing and ability to report data reliably
- Consultation factors: the mode chosen to assess patient (i.e. video/telephone) must be suitable for patient
- Clinical relevance: for use in the patients where a change in level of severity would warrant a change in care, e.g. admission for oxygen therapy/intubation etc. This requires that the ceiling of care is agreed early in discussions with all patients
- Staff factors: Risk to staff, availability of staff. How are abnormal vital signs reported, and who to, and how are they managed? This needs clear processes.
- Identification of appropriate patient whose current health presentation is COVID-19.
- Clinical decision that patient falls into the higher risk period of their COVID illness e.g. 5-10 days from illness onset.
- Potentially has other additional risk factors (e.g. age, sex, co-morbidity).
- Treatment escalation plan is discussed and agreed. Saturation monitoring would be beneficial to onward patient management and aid clinician in decision making.
- Patient is assigned into the model of care which works in this locality (this could be coordinated through the social prescriber in practices (e.g. mobilising the volunteer sectors/family etc.)
Cleaning the equipment:
The recommended decontamination of equipment is shown here .
Patient information and resources:
- If performing a remote assessment using video, verbal instructions can be given to the patient on device use.
- Written instructions have been left with the device in some localities.
What to do with the results that you are given
- Follow your local protocol, this is a rapidly changing area. In general (at the time of publication of this document 23/4/20) saturations of < 94% prompt consideration if an admission is warranted based on the inclusion of other parameters and patient wishes, comorbidity and risk factors.
- You also may be more concerned if a patient desaturates on exertion. A significant desaturation has been defined as 3% in the North West London guidelines. (2)
- Consideration might be needed for patients with compromised lung function (e.g. COPD patients) and those already on oxygen. As an example, the British Thoracic Guidelines have suggested that in COPD Patients:
- Mild deterioration would be defined as up to 2% below their baseline
- Moderate deterioration would be defined as between 3-4% below their baseline
- Severe deterioration would be defined as 5% or more below their baseline
- If on Long Term Oxygen Therapy (LTOT) discuss ceiling of care and consider admission if saturations <88% on their standard dose of LTOT.
- Further guidance can be located here.
How to safety-net patients:
Follow your local guidance on the frequency of monitoring and calls dependent on the patient risk features and also clinical parameters. Safety-net on progressive symptoms such as confusion, dizziness and shortness of breath when walking and in activities of daily living. Other red flags are highlighted in the remote assessment of Covid patients. (3)
Resources list to help triage/add decision making and used in the production of this document
3. https://www.bmj.com/content/368/bmj.m1182 (last accessed 23/04/2020)