Coronavirus Disease 2019 (COVID-19) in Emergency Medicine

Updated: May 11, 2023
  • Author: Melissa Kohn, MD, MS, FACEP, EMT-PHP; more...
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Coronavirus disease 2019 (COVID-19) is the illness associated with the novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus was initially noted during an outbreak of respiratory illness in the population of Wuhan, the capital of Hubei province, China. The first cases were seen in November 2019, with COVID-19 quickly spreading throughout the city. The World Health Organization (WHO) was notified of the outbreak on December 31, 2019. The cases continued to spread outside of the area and then across the world. COVID-19 was reported as a global health emergency by the end of January 2020. As the worldwide case numbers increased, the WHO declared on March 11, 2020, that COVID-19 had reached the pandemic stage. [1]

Infected persons with underlying health conditions seem to be the most vulnerable to succumbing to COVID-19, based on data out of China and Italy. Mortality rates also increase with age, as noted in data from the United States, as well as worldwide. This is related to the fact that persons over age 65 years, but especially those over age 85 years, are more likely to have a severe form of the illness. [2]


Differential Diagnosis

The initial stages of COVID-19 infection are nonspecific and include symptoms typical of multiple respiratory illnesses, viral and otherwise. [3, 4]

Viral infections (which may occur simultaneously with COVID-19) in the differential diagnosis include the following [3, 4] :

  • Influenza
  • Parainfluenza
  • Human metapneumovirus
  • Human rhinovirus
  • Adenovirus
  • Respiratory syncytial virus

Bacterial infections in the differential diagnosis include the following [3] :

  • Haemophilus influenzae pneumonia
  • Streptococcus pneumoniae pneumonia
  • Moraxella catarrhalis pneumonia

Atypical pneumonia in the differential diagnosis includes the following [3] :

  • Legionellosis
  • Mycoplasma pneumoniae pneumonia

Prehospital Care

When individuals contact local emergency services, the 911 Public Safety Answering Points (PSAPs) may ask callers if they are experiencing symptoms of a viral illness. This information is relayed to the responding provider so preparations can be made for an encounter with the patient, which includes donning the appropriate personal protective equipment (PPE). If there is no mention of COVID-19 symptoms by the caller, EMS providers can nonetheless begin their assessment of patients from a safe distance of at least 6 feet once they have arrived on the scene, with PPE worn if symptoms are concerning. Alternatively, agencies may require crews to wear PPE for all responses, regardless of the complaint. Emergency medical services (EMS) medical directors should be involved in this decision and provide guidance. [5]

Standard precautions are recommended on every call. Current recommended PPE for COVID-19 patients includes the following:

  • N95 (or higher level) respirator; providers should be fit-tested prior to use
  • Eye protection (goggles or a face shield that covers the front and sides of the face)
  • Gloves (disposable)
  • Gown (disposable)

If there is a limited supply of PPE, a facemask can be utilized if there are no aerosolizing procedures being performed. Personal glasses are not considered sufficient eye protection. Gowns may also be limited to aerosolizing procedures if there is a shortage. Once treatment is completed and care has been transferred, PPE should be doffed per agency recommendations, and hand hygiene should be performed. [6, 7]

For patients requiring treatment of respiratory symptoms, extreme caution is advised. Aerosolizing procedures are high risk for transmission of COVID-19. An N95 mask, eye protection, and gown should be required by protocols. If possible, aerosolizing procedures should be performed outside of the ambulance prior to transport. High-risk procedures include:

  • Nebulizer treatments
  • Bag-valve-mask ventilation
  • Oropharyngneal suctioning
  • Continuous positive airway pressure (CPAP) or bi-phasic positive airway pressure (BiPAP)
  • Endotracheal intubation
  • Cardiopulmonary resuscitation (CPR)

A viral and/or high-efficiency particulate air (HEPA) filter should be applied to tubing for ventilation. If transport is required, family members should not ride in the ambulance. If another person, such as a parent, guardian, or medical aide, is needed in the ambulance, he or she should wear a mask. EMS providers should communicate with the receiving facility regarding suspected COVID-19 patients in order for the facility to prepare infection-control measures. [8]

As measured via responding ambulance services, a study by Snooks et al found that in the United Kingdom, the total number of emergency ambulance calls coded as suspected COVID-19 during a 22-week period between February 1 and July 3, 2020, was 604,146, or 13.5% of all emergency ambulance calls during that time. Of those COVID-19 calls made, 79.2% resulted in ambulances being dispatched, and 43.5% resulted in the patient being taken by ambulance to the hospital. [9]



Since prenotification systems exist in most EMS systems, an emergency department (ED) can be notified when EMS is arriving with a patient suspected of having COVID-19. In addition, hospitals may have a means by which primary care offices or potential patients can let the department know that someone with symptoms will be arriving.

Patients arriving at the ED via EMS may already have had some basic triage performed by EMS providers. Critically ill patients may have already been intubated. Patients with intermediate symptoms may present on BiPAP or nebulizer treatments. Both are aerosolizing procedures that require PPE for the receiving staff members in the ED. A patient should either have the nebulizing treatment stopped before entering the department or be transitioned to a non-rebreather mask. Stable patients may only require a small amount of supplemental oxygen via a nasal cannula.

The more difficult patients to triage are those arriving at the ED independently rather than with EMS personnel. Triage staff should be aware of the possibility that any patient coming through their door may have COVID-19. Appropriate PPE should be worn by those performing triage assessments and vital signs. Patients who are suspected of being infected need to have a mask applied promptly. If a patient's symptoms and vital signs are concerning, the patient should be brought into the department for further workup, preferably into a room with a door. Individuals who are more stable may be treated in a predesignated area for patients with mild symptoms who have the potential to be discharged home after evaluation. Patients in such an area should still be kept at least 6 feet apart and remain with masks in place while their disposition is determined. [10]




Initially, a travel history was an important factor in determining which patients were at risk for COVID-19. If a patient had recently traveled to China, specifically the Hubei province, the concern was high for a COVID-19 diagnosis. [11] As the virus spread across the world, other countries were added to the travel history, such as Iran and Italy. Now, however, COVID-19 is spread within communities in the United States, with social history having replaced travel history in the workup. Social history should include whether a patient has been in close contact (within 6 feet) with a known positive patient or a patient under investigation for COVID-19. Additionally, employment questions should include whether a patient is a healthcare worker, as such personnel are potentially at higher risk of contracting the disease, depending on their type of work and/or access to PPE.

Reported symptoms of the illness include fever, fatigue, and nonproductive cough. [12] Other symptoms reported are body aches, shortness of breath, and diarrhea. New symptoms are continuing to be investigated and may include anosmia and dysgeusia. Patients are reporting onset of symptoms over a period of a week, with rapid progression to respiratory distress around day 8.

Severe conditions that patients with COVID-19 have presented with include septic shock, diabetic ketoacidosis, acute kidney injury, acute cardiac injury, and dysrhythmias. [13, 14]

A patient's age and comorbidities are a valuable part of history, with elderly patients, especially those with multiple comorbidities, having higher rates of complications and death. [15] Once patients are admitted to the hospital, there will be more time to obtain additional history. In addition, a patient's family may be able to provide more information regarding travel, social, and medical history. 

Physical exam

Evaluation of vital signs will provide some initial information regarding a possible infection. A high fever may be present, but some patients develop only a low-grade fever when infected. Tachycardia can accompany a fever and may be present in the early stages of shock. Tachypnea can indicate the beginning of respiratory distress. In addition, a pulse oximeter can be used to catch a COVID-19 infection, as many patients have been found on initial assessment to be hypoxic. [16]

Further evaluation of a patient suspected to have COVID-19 infection should be conducted in a private room, preferably one employing negative pressure. The examiner should be dressed with PPE for droplet precautions, including mask, eye protection, gown, and gloves. The remainder of a typical physical exam on a COVID-19–infected patient may reveal increased work of breathing using accessory muscles, circumoral cyanosis, and/or confusion from hypoxia. Lung sounds initially are unremarkable, but the patient can develop a mild expiratory wheeze.

As the disease progresses, fine crackles can be heard, as in early pneumonia. Once a patient has developed acute respiratory distress syndrome (ARDS), course rales and diffuse rhonchi are heard. [13]

The physical exam will continue to evolve throughout the course of the illness. As an inpatient, repeat examinations will help to assess if the patient is progressing to a more critical state. Much of the physical exam, both in the ED and during hospitalization, can be performed by merely observing the patient for outward signs of disease—ie, increased work of breathing, retractions, tachypnea, and diaphoresis—in addition to the aforementioned evaluation of vital signs.



Laboratory studies

Current recommendations regarding viral testing for COVID-19 are based on a patient being symptomatic, having had close contact with a known positive patient, or living in or having engaged in recent travel to an area with high community transmission. Employment as a healthcare worker is another indication for such testing. Priority testing is aimed at hospitalized patients and healthcare workers. The next highest priority are symptomatic patients in long-term care facilities, patients over age 65 years, those with underlying conditions, and first responders. Persons who are not symptomatic may also be considered for testing if supplies allow. [17]  In addition, viral respiratory testing can be considered based on regional prevalence of COVID-19. Although viral testing for influenza, respiratory syncytial virus, and rhinovirus may also be available, co-infection may be seen with these disorders, and therefore, positive results for these conditions would not rule out COVID-19.

SARS-CoV-2 tests can performed on a sample—collected, for example, via a nasopharyngeal, oropharyngeal, nasal midturbinate, or anterior nares swab—using a reverse-transcription polymerase chain reaction (RT-PCR) assay. [18, 19] Unfortunately, current COVID-19 testing is showing variable rates of false negatives. Repeat testing can be performed if there is still a concern regarding diagnosis. Samples from sputum or bronchial lavage are thought to be more accurate than a nasopharyngeal swab. [20]

Other laboratory testing may be indicated, as a variety of abnormalities are being found in COVID-19–infected patients. Most of these tests, however, are more useful for hospitalized patients. The tests may be trended and may indicate whether a patient is either improving or progressing to a more critical state. As may occur in other infections, leukopenia and leukocytosis are common in COVID-19. Other patients have had elevations of liver enzymes, muscle enzymes, C-reactive protein, lactate dehydrogenase, and ferritin. [12, 16]  While D-dimer remains a debatable test, it has been found to be elevated in patients with higher rates of ARDS and death. [21]


Chest radiography is a typical initial imaging study for patients with respiratory symptoms. In COVID-19, a plain chest film may show peribronchial thickening, as is typical in a viral illness; pulmonary infiltrates, which are also seen in pneumonia; or no obvious findings at all.

However, providers concerned about a diagnosis of COVID-19 tend to perform chest computed tomography (CT) scanning, since this seems to support a more definitive diagnosis. [22]  (A patient infected with COVID-19 pneumonia will likely show ground-glass opacities, usually in the lower lobes, although these can also be seen throughout the lungs. [23] ) Nonetheless, chest CT scanning is recommended for patients who are being hospitalized and not as a first-line diagnostic tool. [24] If a patient continues to worsen, a chest CT scan may be indicated to further evaluate the individual's pulmonary status.



Mildly symptomatic patients

Patients with only mild symptoms of fever, cough, and/or body aches are likely to be discharged from the ED rather than require admission, since treatment at home tends to be sufficient. Patients may use over-the-counter medications for symptomatic relief, including antipyretics, analgesics, and cough medications, along with oral hydration. Infected patients should isolate themselves from others in their home as much as possible, [25] and common areas should frequently be disinfected to reduce the risk of virus spread. If an infected patient must leave home, he or she should wear a facemask in order to protect others from infection.

Emergency department care and hospitalization

Patients with COVID-19 who require hospitalization are typically in need of respiratory support. In the ED, such support may mean only a need for oxygen via a nasal cannula, while other patients may be in respiratory arrest, requiring intubation and mechanical ventilation. Aerosol-generating procedures, such as high-flow oxygen and noninvasive positive-pressure ventilation, are high risk for healthcare providers, and strict isolation precautions should be taken. Nebulized medications can be considered in patients with acute bronchospasm who have a known diagnosis of asthma or chronic obstructive pulmonary disease (COPD). Otherwise, these agents have not been found to be useful and come with a high level of risk to providers. [26]  

If quick improvement is not seen, more aggressive measures should be considered. While in the ED, aggressive treatment would likely include preparation for mechanical ventilation. Intubation would typically be performed with the use of rapid sequence intubation, preferably by the most qualified provider. When preoxygenating via bag-valve-mask ventilation or CPAP, precautions must be taken because both are considered aerosolizing procedures. Video laryngoscopy can aid in increasing the distance between the provider and the patient during intubation.

A viral filter needs to be placed in the airway circuit once an endotracheal tube has been inserted. After the patient has been intubated, admission to the hospital will be required. Once the individual has been admitted, intensivists can work to manage the patient's care. [27, 28]

A Canadian study by Leeies et al found that despite changes in ED intubation practices aimed at protecting health-care workers from the spread of SARS-CoV-2, the inhospital mortality rate associated with adverse events from intubation did not differ significantly between patients who were positive for the virus and underwent modified intubation, and those who were negative and underwent the pre-pandemic form of intubation. Moreover, the first-pass success rate did not differ significantly between positive and negative patients, being 92.9% and 91.8%, respectively. The investigators did find that a significantly greater percentage of patients who were positive for SARS-CoV-2 experienced post-intubation hypoxemia than did those who were negative (8.9% vs 3.2%, respectively), although presentation at baseline with hypoxemia was also more common in the positive patients. The report concluded that intubation practices associated with the COVID-19 pandemic apparently produce no worse patient outcomes than do pre-pandemic practices. [29]

A study by Sangal et al looked at models to avoid shortages of qualified emergency medicine physicians across three EDs in a health system during a 12-week pandemic disaster with a 2-week quarantine. The investigators reported that in those models in which the physicians did not have immunity, a three-team unfixed cohort model could avoid ED physician shortages for the entire pandemic if the physician infection rate reached no higher than 50%, while a three-team fixed cohort model lost viability after 11 weeks. Regarding these three-team models and a two-team fixed cohort model, the study found that if immunity existed, “all models behaved similarly initially [with regard to physician attrition] but returned to adequate staffing during week 5 of the pandemic.” [30]


Questions & Answers


What are the differential diagnoses of coronavirus disease 2019 (COVID-19)?

What personal protective equipment (PPE) should emergency crews use to prevent coronavirus disease 2019 (COVID-19) if PPE supplies are limited?

What preparations are made for patients who contact local emergency services in light of coronavirus disease 2019 (COVID-19)?

What personal protective equipment (PPE) should emergency crews use to prevent coronavirus disease 2019 (COVID-19)?

What precautions should emergency crews use during transport of a patient with respiratory symptoms (possible coronavirus disease 2019 [COVID-19])?

What triage precautions should be taken to prepare for EMS hospital admission of a patient with suspected coronavirus disease 2019 (COVID-19)?

What triage precautions should be taken to prepare for hospital admission of a walk-in patient with suspected coronavirus disease 2019 (COVID-19)?

Which history details are important in the evaluation for coronavirus disease 2019 (COVID-19) in the emergency department?

What are the potential symptoms of coronavirus disease 2019 (COVID-19)?

What are the severe complications and comorbidities of coronavirus disease 2019 (COVID-19)?

What are the initial vital signs in typical patients with coronavirus disease 2019 (COVID-19)?

What precautions should be taken during physical exam for coronavirus disease 2019 (COVID-19) in the emergency department?

What are the physical findings of coronavirus disease 2019 (COVID-19) pneumonia and ARDS?

How do physical findings of coronavirus disease 2019 (COVID-19) typically progress in the emergency department?

What are the current recommendations regarding lab testing for coronavirus disease 2019 (COVID-19)?

What types of collection samples can be used for coronavirus disease 2019 (COVID-19) testing?

What lab abnormalities are typically found in coronavirus disease 2019 (COVID-19)?

Which imaging studies are performed in the workup of coronavirus disease 2019 (COVID-19) in the emergency department?

How is mildly symptomatic coronavirus disease 2019 (COVID-19) treated in the emergency department?

How is severe coronavirus disease 2019 (COVID-19) treated in the emergency department?