Clinical Notes : Infection and Sepsis
210. CovidCare@Home
GP led Home Oximetry solutions
Home Observation Chart interpretation
Home Oximetry Patient Instruction Booklet
Hospital led Home Oximetry solutions
Rapid excercise tests for exertional desaturation
NEW2 Guidance on how to complete Observation Chart
Overview
Many individuals who have tested COVID-19 positive are well enough to be treated in self-isolation at home.
Overburdened hospitals are under pressure to quickly discharge COVID-19 patients who have recovered and are well enough to be cared for in at home (1) (2).
The first 14 days after contracting a COVID-19 infection are often characterised by a variety of symptoms that do not warrant referral to A+E or admission to hospital (3)
However, it has been recognised that a proportion of patients presented to hospital significantly hypoxic without perceiving themselves to be overly unwell or breathless, so called Silent Hypoxia (4)
This late presentation leads to them requiring intensive therapies and often poor outcomes. Identifying such patients at an earlier phase in their illness when they are starting to become hypoxic will give opportunities for therapies to be instituted earlier with fewer needing escalation of care to intensive care and ventilation (5)
CovidCare@Home is a system of care, where individuals at home are enabled to measure their own oxymetry, temperature and pulse for 2 weeks.
They report to either their GP or, when discharged from hospital, to a "Virtual Ward" where nurses and doctors monitor the results. They receive a box containing the required eqipment and instructions, to be returned after 14 days.
GP led Home Oximetry solutions
Persons who are well enough to self-isolate at home are ideal candidates for GP led CovidCare@Home monitoring.
In some locations, a Hospital led Virtual Ward is not available. Persons in these locations are prime candidates for GP led CovidCare@Home monitoring.
The GP practice provides the selected patients with a CovidCare@Home box containing the required equipment and instructions.
The box may be collected from the GP's surgery by a Covid free friend or relative for delivery to the patient in isolation at home.
The patient reports directly back to the GP at approved times, and records data daily on the Home Record chart (Observation Chart).
Patients who are chronically hypoxic due to pre-existing disease or for whom escalation to hospital care would be undesirable will need to receive additional care and support to determine their ongoing care needs and may require more bespoke approaches.
Example of GP led CovidCare@Home (UK) : Access
Home Observation Chart
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The normal ranges given in the colored column may need adjustment for individuals with pre-existing co-morbidities
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In the upper box, insert the patient's name
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In the lower box, insert the name and telephone number of the person to be contacted when reporting
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Ensure the patient is familiar with the correct technique for the measurement of :
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temperature, using fit for purpose thermometer
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pulse, obtained from pulse oxymeter
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oxygen saturation, obtained from pulse oxymeter
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Instruct the patient on frequency of data recording
10 reading are recorded on each page. Provide sufficient pages to cover the period or quarantine/monitoring
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The normal ranges given in the colored column may need adjustment for individuals with pre-existing co-morbidities
-
In the upper box, insert the patient's name
-
In the lower box, insert the name and telephone number of the person to be contacted when reporting
-
Ensure the patient is familiar with the correct technique for the measurement of :
-
temperature, using fit for purpose thermometer
-
pulse, obtained from pulse oxymeter
-
oxygen saturation, obtained from pulse oxymeter
-
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Instruct the patient on frequency of data recording
10 readings are recorded on each page. Provide sufficient pages to cover the expected period of quarantine/monitoring.
Home Oximetry Patient Instruction Booklet
Hospital led Home Oximetry solutions
Selected patients are issued a CovidCare@Home box when discharged from hospital.
The patients report directly back to the hospital approved times, and record data daily on the Home Record sheet.
Hospital running a Virtual Ward service usually have a dedicated team comprising a designated :
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nurse to receive and triage the data, support patients and escalate to doctor when required
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doctor to assess and manage red flag cases reported by triage
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contacts in auxillary services for referral as deemed necessary to meet the patient needs arising (mental health, physio, social welfare, etc.)
Example of Health Service Provider led CovidCare@Home (Canada) : Access
Example of Hospital led CovidCare@Home (India) : Access
Example of Consortium led CovidCare@Home (Belgium) : Access
CovidCare@Home box content
The CovidCare@Home box would typically contain :
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digital thermometer
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pulse oxymeter
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home observation chart
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instructions sheet
Further optional content includes :
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surgical masks
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N-95 masks
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gloves
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hand sanitiser
Other equipment that may be issued in specific cases includes :
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home BP recording device
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glucometer
CovidCare@Home algorithm
Rapid excercise tests for exertional desaturation
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) (6).
The 1-minute sit-to-stand test is validated and correlates well with the validated 6-minute exercise test.
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patient stands up fully and sits down as many times as they can in one minute
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oximetry readings taken before and after the test are compared
The 40-step test is less demanding (hence safer) and in more widespread use, but does not appear to have been validated.
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the patient is asked to walk 40 steps on the flat
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oximetry readings taken before and after the test are compared
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.
A 3% drop in polse oximeter reading on excercise is cause for concern in Covid-19.
NEWS2 scoring system
Early warning scores (EWS) are forms of track and trigger scoring systems.
These involve checking basic physiological signs at intervals – tracking and responding to abnormal physiological parameters – triggers.(7)
Concerns regarding the lack of standardisation of EWS across the NHS in the UK, led to the development of the National Early Warning System (NEWS).
The National Early Warning Score (NEWS) was launched by the Royal College of Physicians (RCP) in 2012 to improve the identification, monitoring and management of unwell patients in hospital. (8)
was updated in 2017 to NEWS2
NEWS2 uses six simple physiological parameters as the basis of the scoring system:
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respiration rate
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oxygen saturation
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systolic blood pressure
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pulse rate
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level of consciousness or new confusion
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temperature.
A score iof 0-3 is allocated to each parameter as they are measured, with the magnitude of the score reflecting how extremely the parameter varies from the norm.
The score is then aggregated and uplifted by 2 points for people requiring supplemental oxygen to maintain their recommended oxygen saturation.
Higher scores indicate the need for escalation, medical review and possible clinical intervention and more intensive monitoring (see table one).
NEW2 Score Chart
Note :
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White = Low clinical risk
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Yellow = Low-Medium clinical risk
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Amber = Medium clinical risk
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Red = High clinical risk
Interpretation in Hospital setting
The score can and must be used in its entirety
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score 0-4 = Ward based response
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score 3 in any individual parameter OR aggregare score 5-6 = Response by a clinician or team with competence in the assessment and treatment of acutely ill patients and in recognising when the escalation of care to a critical care team (ICU) is appropriate
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Aggregate score 7 or more = The response team must also include staff with critica care skills, including airways management
NEW2 Observation Chart
NEW2 Guidance on how to complete Observation Chart
Causes of false pulse oximeter readings :
Known factors that can produce falsely HIGH estimates of arterial hemoglobin saturation by pulse oximetry include :
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Dark skin pigmentation, e.g. black and Hispanic race (9)
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As much as 12% of dark skinned individuals with oximeter readings of 92-96% could in fact have a true spO2 as low as 88%
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the presence of carboxyhemoglobin, i.e. CO poisoning, e.g.house fire, motor-vehicle exhaust, faulty domestic heating systems (10)
Known factors that can produce falsely LOW estimates of arterial hemoglobin saturation by pulse oximetry include :
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incorrect technique (11)
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best site is the index finger (thumb ok in children)
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attach sensor flush with tissue surface
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do not compress the probe
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deflate BP cuff if on same arm
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take all readings when the probe is at heart level (not above or below)
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blood pressure should be >80 systolic
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heart rate should be <30 or >200
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the finger should be well perfused (no hypothermia or peripheral vasoconstriction)
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blue or green fingernail polish (12)
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certain skin dyes, e.g. black henna dye (not red henna dye) (13)
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motion, e.g. in Parkinson’s tremor, or fever induced rigors, moving vehicle (14)
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calloused skin (15)
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anemia combined with hypotension (16)
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induced nail dystrophy, e.g. in chemotherapy (17)
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the presence of methemoglobin, e.g. exposure to certain drugs and toxins : e.g. topical benzocaine, herbicides, pesticides, (18)
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severe tricuspid regurgitation (19)
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dyes used in surgery and imaging , e.g. methylene blue, indocyanide green (20)
1. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study.
Zhou F, Yu T, Du R, Fan G, Liu Y, Liu Z, et al.
The Lancet.
2020;395(10229):1054-62
2. Clinical findings in a group of patients infected with the 2019 novel coronavirus (SARS-Cov-2) outside of Wuhan, China: retrospective case series.
Xu XW, Wu XX, Jiang XG,Xu KJ, Ying LJ, Ma CL, et al.
BMJ (Clinical research ed).
2020;368:m606
3. RCGP paper on Virtual Wards, Silent Hypoxia and improvingCOVID outcomes
Royal College of General Practitioners
October 2020
4. Silent hypoxia: A harbinger of clinical deterioration in patients with COVID-19.
Wilkerson RG, Adler JD, Shah NG, Brown R.
The American journal of emergency medicine.
2020:S0735-6757(20)30390-9
5. Early intervention likely improves mortality in COVID-19 infection.
Goyal DK, Mansab F, Iqbal A, Bhatti S.
Clinical Medicine. 2020;20(3):248-50.
6. What is the efficacy and safety of rapid exercise tests for exertional desaturation in covid-19?
Greenhalgh T. et al
CEBM. COVID-19 Evidence Service Team Centre for Evidence-Based Medicine, University of Oxford
April 2020
7. Systematic review and evaluation of physiological track and trigger warning systems for identifying at risk patients on the ward.
Gao H, McDonnell A, Harrison DA, et al.
Intensive Care Medicine. 2007;33:667–79.
8. National Early Warning Score (NEWS) 2
Royal College of Physicians
2012. Updated 2017
9. Dark skin decreases the accuracy of pulse oximeters at low oxygen saturation: the effects of oximeter probe type and gender
J R Feiner et al.
Anaest. Analg.2007 Dec;105(6 Suppl):S18-23
10. Causes and clinical significance of increased carboxyhemoglobin
Higgins C
Acuteceretesting.org
October 2005
11. Factors Affecting Pulse Oximeter Readings
Monroe Community College, State University, New York
Accessed online February 2021
12. The effect of nail polish on pulse oximetry.
Cote CJ, Goldstein EA, Fuchsman WH, Hoaglin DC.
Anesth Analg 1988;67:683–6
13. The effect of henna paste on oxygen saturation reading obtained by pulse oximetry.
al-Majed SA, Harakati MS.
Trop Geogr Med 1994;46:38–9.
14. The effects of motion on the performance of pulse oximeters in volunteers
Barker SJ, Shah NK.
Anesthesiology 1997;86:101–8
15. Pulse oximeter a valuable tool, but has limitations
L. Kirkland
ACP Hospitalistt
December 2009
16. Effect of anemia on pulse oximeter accuracy at low saturation.
Severinghaus JW, Koh SO
J Clin Monit 1990;6:85–8.
17. Falsely Low Pulse Oximetry Values in Patients Receiving Docetaxel
Paige M et al
Anesthesia & Analgesia: August 2004 - Volume 99 - Issue 2 - p 622-623
18. Pulse oximetry in methemoglobinemia
Watcha MF, Connor MT, Hing AV
Am J Dis Child 1989;143:845–7.
19. Inaccuracy of pulse oximetry in patients with severe tricuspid regurgitation.
Stewart KG, Rowbottom SJ
Anaesthesia 1991;46:668–70
20. Sources of error in pulse oximetry
Anaesthesia UK
October 2004
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