Most (80-90%) COVID-19 positive patients are asked to self-isolate at home because they do not qualify for home care or inpatient admission. Alternatives to in-person care are urgently needed to: (1) manage an unpredictable clinical course; (2) identify and intercept patients rapidly deteriorating at home, (3) prevent viral spread during in-person visits; and (4) triage symptoms to minimize surges to emergency departments (EDs). In addition, fingertip pulse oximeters ("pulse oximetry") have been proposed to improve in-home early detection of respiratory deteriorations but are untested and the operational infrastructure to support large-scale monitoring is limited. While telemedicine has been widely adopted during the pandemic as an alternative to conventional outpatient care, worse COVID-19 outcomes observed among Black and Latino patients may be due, in part, to worse telemedicine access for these socially and medically disadvantaged groups.

To improve in-home monitoring and health care access for patients with suspected or confirmed COVID-19, the health innovation team at University of Pennsylvania Health System ("UPHS") developed COVID Watch, a free of charge, 24/7, automated, text message-based, home monitoring program across UPHS' large geographic catchment area. This study will answer the question, "How does the addition of pulse oximetry affect clinical outcomes for COVID-19 patients?"

COVID Watch was first implemented on March 24, 2020 and has enrolled 3,628 patients through May 21, 2020 of which 1,295 were COVID-19 positive. Understanding the effect of COVID Watch with and without pulse oximetry on Black and Latino patients is important because communities of color have had disproportionately higher rates of COVID-19 morbidity and mortality nationally, and locally in Pennsylvania, ranking 5th total deaths, and New Jersey, ranking 2nd. Symptom monitoring apps and programs are commercially available. However, COVID Watch is uniquely embedded into its host healthcare system, UPHS. Patients are enrolled using the electronic medical record (EMR), escalations are addressed by UPHS nurses, and they are referred to UPHS-based telemedicine, primary care, and social services when appropriate. COVID Watch is a scalable operational platform for monitoring patients with home pulse oximetry readings. Whether remote monitoring with or without pulse oximetry helps COVID-19 patients stay safe at home is an urgent, patient-centered question. Finally, with COVID-19 surges projected in late 2020, health systems will need to be prepared with evidence-based strategies for managing more COVID-19 patients at home.

COVID Watch (https://covidwatch.waytohealth.org/) is powered by UPHS' NIH-funded research and operational texting platform (www.waytohealth.org), integrated with UPHS' EMR. Since hypoxemia is the primary driver of admission and fatality among COVID-19 patients, the investigators focused the algorithm on shortness of breath, our closest approximation for concerning hypoxemia. Given the rapid and unpredictable decompensation of COVID-19 patients, patients receive clinical support 24 hours/day, 7 days/week. COVID Watch sends twice-daily, scheduled text messages to assess patients for shortness of breath using an algorithm to determine whether patients need an urgent escalation to a team of dedicated nurses within 1 hour. These nurses are supported by an on-call team of clinicians who can conduct urgent phone or video assessments. At each level patients' clinical needs are either managed with self-care advice, prescriptions, or a referral to the ED. The majority of COVID Watch patients (83.7%) have been enrolled by outpatient providers conducting telephone and video visits; 8.7% and 7.6% have been enrolled at ED and inpatient discharge, respectively. The program is available at all six of UPHS's hospitals and EDs, and all 530 affiliated ambulatory settings using the EMR. Any clinical staff member (e.g., RN, physician, medical assistants) logged on to the EMR is able to enroll patients. Patients can also trigger the algorithmic assessment independent of the scheduled messages. Patients only continue the intervention if they are agreeable ("opt-out") and can stop anytime. Patients are scheduled to be in COVID Watch for 14 days, with the option to extend to 21 days if interested. A Spanish-language version of COVID Watch was made available to patients on May 18, 2020, with nurses using translation lines to communicate with patients.

COVID Watch engagement is high. To date, nearly 80% of enrolled patients have engaged with the program, defined as responding to scheduled text messages at least once every two days. RNs have managed over 600 calls with a mean response time (median) of 25 minutes (11 minutes). Of the calls, 37% were asked to continue to monitor at home, 41% were scheduled for an urgent follow-up telemedicine visit, and 9% were sent to the ED for emergent evaluation.

The investigative team provides a conceptual model of how adding home pulse oximetry may potentially improve outcomes. Preventing or aggressively treating respiratory failure is essential for patients infected with COVID-19. Among all infected patients, an estimated 10-20% of patients with COVID-19 develop severe illness requiring hospitalization, of which 30-40% develop critical illness requiring support in an intensive care unit. Among the critically ill, respiratory failure is common and results from acute hypoxemic respiratory failure due to acute respiratory distress syndrome (ARDS). ARDS is a clinical manifestation of pulmonary tissue inflammation, preventing the exchange of oxygen between inhaled air and blood circulating in patients' lungs ("hypoxemia"). Increasing the concentration of oxygen in the air that patients breathe (e.g., supplemental oxygen) and reducing the degree of pulmonary inflammation can support patients with COVID-19 by reducing the severity of hypoxemia and providing sufficient oxygen supply to vital organs. Measures of pulse oximetry - the oxygen saturation in the blood - can provide an objective measure to identify which patients have or are beginning to experience declines in their respiratory function.

The investigators' conceptual model is based on emerging evidence that early medical interventions can improve clinical outcomes for COVID-19, resulting in less severe clinical sequelae and reduced mortality. For COVID-19 patients requiring supplemental oxygen, new preliminary data from a large multicenter randomized controlled trial of dexamethasone indicates that patients have markedly reduced mortality when given dexamethasone. This corticosteroid likely reduces pulmonary inflammation and prevents the development of severe ARDS. These findings suggest that earlier treatment for patients who develop more severe forms of COVID-19 may prevent unwanted outcomes. Secondly, there is additional evidence that remdesivir can speed recovery and reduce hospital days among patients with COVID-19. Finally, there is promising data that simple changes in ED care and hospital practices may improve outcomes. For example, "awake proning," which involves positioning an awake, non-intubated patients at regular intervals onto their abdomen with their face down can enable greater recruitment of lung tissue for oxygen exchange and reduce the need for subsequent intubation and mechanical ventilation. These sorts of interventions can reduce the days that patients spend in the hospital, prevent complications such as ventilator associated pneumonia, and reduce mortality related to COVID-19.

Respiratory decline needs to be identified early for patients to benefit from early medical interventions. Respiratory decline can be (a) signaled when patients report the sensation of feeling "shortness of breath" or "difficulty breathing" (i.e., dyspnea), or (b) identified when the concentration of oxygen in patients' blood or oxygen saturation are objectively measured. Current models of care ("Usual Care"), even with expanded telemedicine access, rely on patients contacting providers - a reactive process. This reactive process can delay care because most primary care practices use an intermediary (e.g., a staff member or message inbox) to screen communications for busy clinicians. Many practices do not respond to patients' concerns efficiently overnight or on weekends. These processes frustrate patients because they are concerned about contacting their providers for mild changes, irrespective of the time or day the event is occurring, because they are concerned about respiratory failure. This process is even harder for patients with limited primary care or telemedicine access or language barriers, problems disproportionately faced by Black and Latino communities. In contrast, COVID Watch is a proactive process, requesting patients report symptoms twice a day, and patients can trigger a phone call to a nurse within an hour by simply texting. COVID Watch + pulse oximetry mirrors COVID Watch but can proactively detect respiratory decline using an objective measure of oxygen saturation. In addition, COVID Watch is available free of charge and is now available in Spanish, with over 85 Spanish speaking patients enrolled to date.

To not overburden emergency departments (EDs), respiratory decline needs to be identified accurately. Both unnecessary escalations of care to the ED for patients with mild COVID-19 and delayed detection of respiratory decline in patients with severe COVID-19 may occur when managing patients with COVID-19. For usual care and COVID Watch, clinicians are reliant on the subjective sensation of dyspnea. Dyspnea is concerning enough that patients are often redirected to an urgent care center or emergency department so patients can have their oxygen saturation measured. Referring patients with an oxygen saturation \<94% would justify redirecting patients to the ED for additional clinical evaluation and supportive therapy. Referring patients with mild dyspnea who turn out to have a normal oxygen saturation may be a burden to patients and their families and requires additional resource from EDs and hospitals. During times of rapid rises in community infection rates, or surges, efficient resource allocations are imperative for supporting patients who are critically ill. At the same time, patients still benefit from enhanced connections with clinical providers to reassure them that they are not experiencing respiratory decline. COVID Watch, supplemented by pulse oximetry, could provide this highly responsive team of clinicians objective data so they can accurately assess a patient's respiratory state.

In an alternative scenario, patients may have low oxygen saturation without the sensation of dyspnea, a phenomenon unique to COVID-19 infected patients, and is commonly known as "silent" or "happy" hypoxemia. These patients receive medical interventions late because they are unaware they are hypoxemic. There have been reports of COVID-19 patients arriving in EDs with profoundly low oxygen saturation levels with relatively little or no dyspnea. This has led to proposals to use home pulse oximetry to detect silent hypoxemia which have been widely reported in the media (e.g. New York Times) and resuscitation medicine forums. To address this phenomenon, the Vermont Department of Public Health has implemented a program to mail pulse oximeters to newly diagnosed COVID-19 cases 24-48 hours after contact tracing interviews. But as reported in Science: "No one, however, has studied whether early detection of hypoxia might head off bad outcomes. Some physicians believe pulse oximeters are best used with a doctor's guidance, perhaps through telemedicine. With many COVID-19 patients frightened to visit a hospital and arriving only when their symptoms have dangerously advanced, doctors also wonder whether home monitoring could hasten treatment-and whether, for some, that could make all the difference."

Based on lack of studies determining whether pulse oximetry can hasten treatment for patients deteriorating at home relative to the current standard of care in the health system of automated text messaging paired with telemedicine, the investigators believe there is equipoise between these two treatment strategies: automated text messaging with telemedicine vs. automated text messaging with telemedicine plus pulse oximetry. Therefore, a randomized comparison is needed to guide health system programs to better address this pandemic.