Pulse Oximetry is Essential in Home Management of Elderly COVID-19 Patients

Background: Coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) is in Pandemic form and has affected people of 215 countries. It produces symptoms like fever, cough, shortness of breath, sore throat, headache, loss of taste, smell or appetite and many other rare symptoms. But the most important symptom is shortness of breath due to hypoxia. In a normal individual oxygen saturation (SpO 2 ) is at least 95% and patient feels shortness of breath when SpO 2 falls below 90% with some exception. SARS-CoV-2, a newly emergent coronavirus has the peculiarity to produce silent hypoxia, meaning SpO 2 < 90% or less like 80%, 70%, 60% without shortness of breath. Silent hypoxia can be diagnosed by monitoring SpO 2 with pulse oximeter. For management of COVID-19, early symptoms like fever & cough, SpO 2 should be monitored by pulse oximeter, followed by immediate correction of hypoxia by O 2 supplementation and prophylactic oral or injectable anticoagulant to prevent thromboembolism and thus death rate can be reduced. Case summary: A 72-year-old man presented with the complaints of fever and headache followed by cough, fatigue, anorexia, loss of taste and appetite in next few days but no shortness of breath. The patient was clinically diagnosed as a case of COVID-19 & positive result of Real time-Polymerase Chain Reaction (RT-PCR) test confirmed the diagnosis. From the first day, SpO 2 was regularly monitored with pulse oximeter and SpO 2 on day 1, it was 96-98%. On day 8, SpO 2 fell to 89-93%, pulse 96/min, respiratory rate>30/min, temperature 101 F, taste sensation was reduced. According to sign and symptoms, the patient was diagnosed as COVID-19 with severe pneumonia. Management was started at home with continuous monitoring, lying in prone position for 5-6 hours/day, supplemental oxygenation to maintain level of SpO 2 between 94-96%, injectable anticoagulant enoxaparin to prevent venous thromboembolism (VTE) and disseminated intravascular coagulation (DIC) was given. Prophylactic antibiotics and symptomatic treatment were also given. Results: According to this case report, patient’s SpO 2 was monitored by pulse oximeter on first day; on day 08, SpO 2 fell to 89-93% & on day 10, further dropped to 85-88% which **Details of the authors and contributors included at the end of the article. Address of Correspondence: Md. Abdullah Al Harun, Assistant Professor (ENT), Shaheed Suhrawardy Medical College, Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh, +8801678139788, Email: harun.dr.99@gmail.com

Affected cases are confirmed by Real time-Polymerase Chain Reaction (RT-PCR) test was done for SARS-CoV-2 (COVID- 19) and positive result confirmed the diagnosis. There may be many cases having COVID-19 like clinical symptoms without going for RT-PCR test, so total number of COVID-19 cases may be more. COVID-19 infected patients develop only mild (40%) or moderate indicated severe pneumonia but there was no complaint of breathlessness as it was silent hypoxia. Sometimes the patient spent 30 minutes or more in toilet and SpO 2 used to fall to 82-83% without any subjective shortness of breath but with only mild heaviness of chest and cough. Therefore SpO 2 monitoring by pulse oximeter is essential in early diagnosis of silent hypoxia. Correction of hypoxia by supplemental oxygenation and prevention of VTE and DIC by using anticoagulant was the mainstay of treatment and patient had significant improvement on day 14. The patient was managed completely at home except X-ray being done in a hospital. (40%) symptoms and approximately 15% develop severe disease that requires oxygen (O 2 ) supplementation and 5% have critical diseases with complications such as respiratory failure, ARDS, sepsis and septic shock, thromboembolism and/or multiple organ failure including acute kidney injury and cardiac injury. Most of the SARS-CoV-2 infected patients are men (73%) 2 . Older age, smoking, co-morbidities such as diabetes, hypertension, cardiac disease, chronic lung disease are the risk factors for severe disease 4,6,7 . Severe coronavirus disease is commonly complicated with coagulopathy and DIC may exist in the majority of death 8,9 .
Common symptoms of COVID-19 diseases are fever, cough, fatigue, anorexia, shortness of breath, myalgias. Other non-specific symptoms such as sore throat, nasal congestion, headache, diarrhoea, nausea and vomiting, loss of taste, appetite & smell may present in some cases 2,4 .Shortness of breath occurs due to hypoxia which means SpO 2 < 90% but with COVID-19 disease SpO 2 reduced below normal level may be down to 70%, 60% or 50% but patient had no feeling of breathlessness. 10,11 He can continue his own job without any breathing problem which makes the patient more vulnerable.
SpO 2 is an essential element in the management and understanding of patient's care which measures how much haemoglobin is currently bound to oxygen compared to how much haemoglobin remains unbound. 12 A pulse oximeter is a noninvasive medical device placed over a person's finger to monitor blood oxygen saturation. 13,14 It is routinely used in operation theatre, Intensive Care Unit (ICU) and postoperative ward in hospital. Investigation results other than RT-PCR test like normal or low total count of WBC, lymphopenia, nutrophil lymphocyte ratio, high C-Reactive Protein(CRP), low procalcitonin, significant elevation of D-Dimer & S. Ferritin level, associated with bilateral pneumonia in CXR or ground glass opacities (GGO) and Crazy paving appearance in CT scan of chest suggest presence of COVID-19 during this pandemic situation. 15 Till today O 2 supplementation to correct hypoxia and prevention of VTE and DIC by using anticoagulant is the mainstay of treatment for COVID-19. Other advice like lying in prone position, mild breathing exercise, adequate nutrition & symptomatic treatment like antibiotics to prevent secondary infections, paracetamol for fever, montelukast and other medications are used during management. For home management of COVID-19 patients, proper caring by relatives or a professional nurse and required medication should be confirmed. 6 This case study focuses on early diagnosis of hypoxia without shortness of breath by pulse oximeter which monitors SpO 2 , also can be monitored by pulse oximetry apps installed on smart mobile phones. When SpO 2 is 94% or less, O 2 supplementation should be given to maintain SpO 2 above 94% 4 and oral anticoagulant apixaban/ rivaroxaban or injectable Low Molecular Weight Heparin (LMWH) Enoxaparin may be given to prevent VTE or DIC in home management.

Case Presentation:
A 72-year-old man, father of the first author staying with him at the same home developed symptoms like fever and headache on May 21, 2020 [day 1of COVID-19 (D-1)]. First author developed symptoms of COVID-19 on May 13, 2020 and confirmed by RT-PCR test on May 16, 2020. The first author was isolated in a room with attached toilet and for contact tracing RT-PCR test was done to patient (father of 1 st author), patient's wife (mother of 1 st author) and 6 th author (wife of 1 st author) on May 21, 2020 and all RT-PCR test result became positive. As RT-PCR test is a confirmatory test, patient was diagnosed as a case of COVID-19.
The patient is hypertensive controlled on drug and according to risk factors for COVID-19 advised by World Health Organization (WHO) patient's age being more than 60 years, had co-morbidity like hypertension, so the patient was in risk group and monitored from D-1. Pulse oximeter was arranged at home to monitor SpO 2 which was 96-98%. From D-1 patient's SpO 2 , temperature, pulse, respiratory rate & taste sensation was routinely monitored 3 times a day. Patient gradually developed cough, fatigue, anorexia, nausea, nasal congestion, loss of appetite & taste which gradually deteriorated. He had no sign of shortness of breath, sore throat, diarrhoea or loss of smell (Tabel:I).
Presence of symptoms (D 1 to D 21). D 7-D12 all symptoms were present( Shaded area).
From May 26, 2020 (D-6) SpO 2 fell to 93-96% and gradually deteriorated. On May 28, 2020 (D-8) SpO 2 fell to 89-93%, respiratory rate>30/min, pulse 96/min, temperature 101 o F and taste sensation was reduced. According to sign and symptoms, patient was clinically diagnosed as COVID-19 with severe pneumonia. Immediate management was started at home with supplemental oxygenation from O 2 cylinder with nasal cannulas to maintain the SpO 2 between 94-96%.
During management, monitoring of SpO 2 for 24 hours was difficult to maintain. During toilet use, patient refused to take O 2 and after coming from toilet, SpO 2 used to go down to 82-83% for few minutes due to absence of O 2 supply which had to immediately corrected by higher flow of oxygen than earlier. Ecchymosis developed associated with mild pain in the injection site of paraumbilical region (Fig: II) due to Enoxaparin which was gradually diminished.

Fig 3: SpO 2 and heart rate (pulse) in smart phone
CoV-2 virus is at exponentially rising state across the globe. Bangladesh is also facing this highly transmissible zoonotic disease with community transmission across the country. In Bangladesh it was declared as pandemic on April 16, 2020. 16  Other than pulse oximeter, patient's condition was monitored with total count of WBC and ratio of neutrophil to lymphocyte. Decreased number of lymphocytes or the ratio of neutrophil to lymphocyte more than 3.5 is prognostically poor sign. Rapid and significantly elevated CRP indicates possibility of secondary infection. D-dimer is a biomarker of fibrin formation and degradation which might help in early recognition of these high risk patients and also predict outcome. 15 D-dimer and Ferritin are elevated in severe cases of pneumonia, which is a potential risk factor for poor prognosis. 14 When SpO 2 falls below 94%, prophylactic injectable anticoagulant LMWH enoxaparin was given from the first day of severe pneumonia to prevent VTE & DIC which prevent further damage of lungs parenchyma. Enoxaparin given in right and left side of umbilicus on alternative days, causes ecchymosis, pain & indurations at the site of injection. Another direct oral anticoagulant (DOAC) tablet rivaroxaban 10mg daily which was started on June 7, 2020 (Day-18) for next 10 days. Elevated Ddimer indicates increased risk of abnormal blood clotting and its level above 1µg/ml was a strong and independent risk factor for death in these patients. [20][21][22][23][24] Patient with Ddimer more than six times of the upper limit of normal level comprise in a higher proportion of severe cases. 24 Early anticoagulation is necessary to prevent propagation of microthrombi at disease presentation and anticoagulation may be associated with decreased mortality. 25 Injectable LMWH enoxaparin is the best choice of anticoagulant for hospital admitted patients due to its anti inflammatory action. 26 DOAC drugs are oral selective Factor Xa inhibitors and decreases thrombin generation and blood clot formation. 18,27 The advantages of DOAC drugs like apixaban/ rivaroxaban are: they can be given as fixed doses, do not require monitoring, rapid onset of action, high oral bioavailability when being taken with food, low cost & self medication. 18 In comparison LMWH enoxaparin, apixaban/ rivaroxaban has no anti-inflammatory action and using with antiviral drugs cause high rise of plasma level of apixaban/rivaroxaban which increases haemorrhagic risk, so it should not be used with antiviral drugs. 28,29 The incidence of VTE is low in Asian population and therefore routine VTE is not frequently used. 24  These recommendations need further research and trial to establish the observation of the authors. 3 These complications ultimately cause death. To reduce death early diagnosis of silent hypoxia is strongly recommended by the authors. Pulse oximeter can diagnose hypoxia by measuring SpO 2 with or without breathlessness. Pulse oximetry apps in smart mobile phone can be a good alternative of pulse oximeter. Patients with older age, habit of smoking & co-morbidities are in risk group for severe diseases of COVID-19 30 . So, our recommendation is that, in this pandemic situation when elder patient feels fever, it should be clinically diagnosed as COVID-19 without waiting for RT-PCR test result and SpO 2 should be monitored 3 times a day to diagnose hypoxia. First oral anticoagulant apixaban/ rivaroxaban may be started as prophylaxis to prevent VTE & DIC if there is no history of bleeding disorder & patient not taking any antiviral drugs 28