19 Questions and Answers on the COVID-19 Pandemic from a Emergency Medicine-based Perspective

covid 19 - from a Emergency Medicine-based Perspective

1) What is COVID-19?

Corona Virus Disease 2019 (COVID-19) is the disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

2) What is SARS-CoV-2?

SARS-CoV-2 is a virus belonging to the Coronaviridae family. Spike proteins (S proteins) on the outer surface of SARS-CoV-2 are arranged in a way that resembles the appearance of a crown when viewed under an electron microscope (see Figure 1). S proteins facilitate viral entry into host cells by binding to the angiotensin-converting enzyme 2 (ACE2) host receptor. Several cell types express the ACE2 receptor, including lung alveoli cells. [1].

Morphology of the SARS-CoV-2
Figure 1 - Morphology of the SARS-CoV-2 viewed under an electron microscope.Note the spikes that adorn the outer surface of the virus, which impart the look of a corona surrounding the virion. (https://phil.cdc.gov/Details.aspx?pid=23312)

3) How is SARS-CoV-2 transmitted?

Viral particles can spread from person-to-person through airborne transmission (e.g., large droplets) or direct contact(e.g., touching, shaking hands). We have to remember that large droplets are particles with a diameter > 5 microns and that they can be spread by coughing, sneezing, talking, etc., so do not forget to wear full PPE in the Emergency Department (ED). Other potential routes of transmission are still being investigated.

4) What is the incubation time?

In humans, the incubation period of the SARS-CoV-2 varies from 4 days to 14 days, with a median of about 4 days [2].

5) Can we say the COVID-19 is like the seasonal flu?

No, we can’t say that. COVID-19 differs from the flu in several ways:

  • First of all, SARS-CoV-2 replicates in the lower respiratory tract at the level of the pulmonary alveoli (terminal alveoli). In contrast, Influenza viruses, the causative agents of the flu, replicate in the mucosa of the upper respiratory tract.
  • Secondly, SARS-CoV-2 is a new virus that has never met our adaptive immune system.
  • Thirdly, we do not currently have an approved vaccine to prevent infection by SARS-CoV-2.
  • Lastly, we do not currently have drugs of proven efficacy for the treatment of disease caused by SARS-CoV-2.

6) Who is at risk of contracting the COVID-19?

We are all susceptible to contracting the COVID-19, so it is essential that everyone respects the biohazard prevention rules developed by national and international health committees. Elderly persons, patients with comorbidities (e.g., diabetics, cancer, COPD, and CVD), and smokers appear to exhibit poor clinical outcome and greater mortality from COVID-19 [3]

7) What are the symptoms of the COVID-19?

There are four primary symptoms of COVID-19: feverdry coughfatigue; and shortness of breath (SOB).

Other symptoms are loss of appetite, muscle and joint pain, sore throat, nasal congestion and runny nose, headache, nausea and vomiting, diarrhea, anosmia, and dysgeusia.

8) What is the severity of symptoms from COVID-19?

In most cases, COVID-19 mild or moderate symptoms, so much so it can resolve after two weeks of rest at home. However, onset of severe viral pneumonia requires hospital admission.

9) Which COVID-19 patients we should admit to the hospital?

The onset of severe viral pneumonia requires hospital admission. COVID-19-associated pneumonia can quickly evolve into respiratory failure, resulting in decreased gas exchange and the onset of hypoxia (we can already detect this deterioration in gas exchange with a pulse oximeter at the patient’s home). This clinical picture can rapidly further evolve into ARDS and severe multi-organ failure.

The use of the PSI/PORT score (or even the MuLBSTA score, although this score needs to be validated) can help us in the hospital admission decision-making process.

10) Do patients with COVID-19 exhibit laboratory abnormalities?

Most patients exhibit lymphocytopenia [11], an increase in prothrombin time, procalcitonin (> 0.5 ng/mL), and/or LDH (> 250 U/L).

11) Are there specific tests that allow us to diagnose COVID-19?

RT-PCR is a specific test that currently appears to have high specificity but not very high sensitivity [12]. We can obtain material for this test from nasopharyngeal swabs, tracheal aspirates of intubated patients, sputum, and bronchoalveolar lavages (BAL). However, the latter two procedures increase the risk of contagion.

However, since rapid tests are not yet available, RT-PCR results may take days to obtain, since laboratory activity can quickly saturate during epidemics. Furthermore, poor pharyngeal swabbing technique or sampling that occurs during the early stage of COVID-19 can lead to further decreased testing sensitivity.

Consequently, for the best patient care, we must rely on clinical symptoms, labs, and diagnostic imaging (US, CXR, CT). The use of a diagnostic flowchart can be useful (see Figure 2).

diagnostic flow chart
Figure 2 - A possible diagnostic flow chart for an ill patient admitted to hospital with suspected COVID-19 (from EMCrit Blog)

12) Can lung ultrasound help diagnose COVID-19?

Yes, it can help! The use of POCUS lung ultrasound is a useful method both in diagnosis and in real-time monitoring of the COVID-19 patient.

In addition, we could monitor the patient not only in the emergency department (ED) or intensive care unit (ICU), but also in a pre-hospital setting, such as in the home of a patient who is in quarantine.

In fact, POCUS lung ultrasounds not only allows one to anticipate further complications such as lung consolidation from bacterial superinfection or pneumothorax, but it also allows detection of viral pneumonia at the early stages. Furthermore, the use of a high-frequency ultrasound probe, which is an adoption of the 12-lung areas method [4] and the portable ultrasound (they are easily decontaminated), allow this method to be repeatable, inexpensive, easy to transport, and radiation-free.

There are no known pathognomonic patterns of COVID-19.

The early stages COVID-19 pneumonia results in peripheral alveolar damage including alveolar edema and a proteinaceous exudate [5]. This interstitial syndrome can be observed via ultrasound by the presence of scattered B lines in a single intercostal space (see videos below).

Subsequently, COVID-19 pneumonia progression leads to what’s called “white lung”, which ultrasound represents as converging B lines that cover the entire area of the intercostal space; they start from the pleura to end at the bottom of the screen.

Finally, the later stages of this viral pneumonia lead to “dry lung”, which consists of a pattern of small consolidations (< 1 cm) and subpleural nodules. Unlike bacterial foci of infection, these consolidations do not create a Doppler signal within the lesions. We should consider the development from “white lung” to “dry lung” as an unfavorable evolution of the disease.[6]

(the 5 videos above come from the COVID-19 gallery on the Butterflynetwork website)

13) Can CXR/CT help us in the diagnosis of COVID-19?

Yes, it can help! There are essentially three patterns we observed in COVID-19.

In the early stages, the main pattern is ground-glass opacity (GGO)[7]. Ground glass opacity is represented at the lung bases with a peripheral distribution (see videos below) .

The second pattern is constituted by consolidations, which unlike ground-glass opacity, determine a complete “opacification” of the lung parenchyma. The greater the extent of consolidations, the greater the severity and the possibility of admission in ICU.

The third pattern is called crazy paving[8]. It is caused by the thickening of the pulmonary lobular interstitium.

However, we should consider four things when we do a CXR/CT exam. First, many patients, especially in the elderly, exhibit multiple, simultaneously occurring pathologies, so it is possible to clinically observe nodular effusions, lymph node enlargements, and pleural effusions that are not typical of COVID-19 pneumonia. Secondly, we have to be aware that other types of viral pneumonia can also cause GGO, so they cannot be excluded during the diagnostic process. Thirdly, imaging can help evaluate the extent of the disease and alternative diagnoses, but we cannot use it exclusively for diagnosis. Lastly, we should carefully assess the risk of contagion from transporting these patients to the CT room.

14) What is the treatment for this type of patient?

COVID-19 patients quickly become hypoxic without many symptoms (apparently due to “silent” atelectasis). Therapy for these clinical manifestations is resuscitation and support therapy. In patients with mild respiratory insufficiency, oxygen therapy is adopted. In severe patients in which respiratory mechanics are compromised, non-invasive ventilation (NIV) or invasive ventilation should be adopted.

15) How can we non-invasively manage the airways of patients with COVID-19?

In the presence of a virus epidemic, we should remember that all the procedures that generate aerosolization (e.g., NIV, HFNC, BMV, intubation, nebulizers) are high-risk procedures.

Among the non-invasive oxygenation methods, the best-recommended solution is to have patients wear both a high-flow nasal cannula (HFNC) and a surgical mask[9]. Still, we should also consider using CPAP with a helmet interface. Furthermore, we should avoid the administration of medications through nebulization or utilize metered-dose inhalers with spacer (Figure 3).

Figure 3 – General schema for Respiratory Support in Patients with COVID-19 (from PulmCrit Blog)

16) How can we invasively manage the airways of patients with COVID-19?

We should intubate as soon as possible, even in non-critical conditions (Figure 3). Intubation is a high contagion risk procedure. As a result, we should adopt the highest levels of precaution[10]. To be more precise:

  • As healthcare operator, we should wear full PPE. Only the most skilled person at intubation in the staff should intubate. Furthermore we should consider using a video laryngoscope. Last but not least, we should ensure the correct positioning of the endotracheal tube without a stethoscope (link HERE).
  • The room where intubation occurs should be a negative pressure room. When that is not feasible, the room should have doors closed during the intubation procedure.
  • The suction device  should have a closed-circuit so as not to generate aerosolization outside.
  • Preoxygenation should be done using means that do not generate aerosols. Let us remember that HFNC and BVM both can generate aerosolization. So, it is important to remember to turn off the flow of the HFNC before removing it from the patient face to minimize the risk and to use a two-handed grip when using BVM, interposing an antiviral filter between the BVM and resuscitation bag and ventilating gently.
  • Intubation drugs that do not cause coughing should be used. In addition, we should evaluate the use of Rocuronium in the Rapid Sequence Intubation (RSI) since it has a longer half-life compared to succinylcholine and thus prevents the onset of coughing or vomiting.

In conclusion, let us remember that intubation, extubation, bronchoscopy, NIV, CPR prior to intubation, manual ventilation etc. produce aerosolization of the virus, therefore, it is necessary that we wear full PPE.

17) What is the drug therapy for COVID-19?

Currently, there is no validated drug therapy for COVID-19. Some drugs are currently under study. They include Remdesivir (blocks RNA-dependent RNA polymerase), Chloroquine and Hydroxychloroquine (both block the entry of the virus into the endosome), Tocilizumab and Siltuximab (both block IL-6).

18) Is there a vaccine available for COVID-19?

No, there is still no vaccine currently available to the public.

19) What precautions should we take with COVID-19 infected patients?

As healthcare professionals, we should wear full personal protective equipment (PPE) and know how to wear them (“DONning”) and how to remove them properly (“DOFFing”) (see video below). Furthermore, we should wear full PPE for the entire shift and when in contact with patients with respiratory problems.

Resources on COVID-19

Cite this article as: Francesco Adami, Italy, "19 Questions and Answers on the COVID-19 Pandemic from a Emergency Medicine-based Perspective," in International Emergency Medicine Education Project, March 27, 2020, https://iem-student.org/2020/03/27/19-questions-and-answers-on-the-covid-19/, date accessed: November 25, 2020


[1] Zheng YY, Ma YT, Zhang JY, Xie X. COVID-19 and the cardiovascular system. NatRev Cardiol. 2020 Mar 5.

[2] del Rio C, Malani PN. COVID-19—New Insights on a Rapidly Changing Epidemic. JAMA. Published online February 28, 2020. doi:10.1001/jama.2020.3072

[3] Yee J et al. Novel coronavirus 2019 (COVID-19): Emergence and Implications for Emergency Care. Infectious Disease 2020. https://doi.org/10.1002/emp2.12034

[4] Belaïd Bouhemad, Silvia Mongodi, Gabriele Via, Isabelle Rouquette; Ultrasound for “Lung Monitoring” of Ventilated Patients. Anesthesiology 2015;122(2):437-447. doi: https://doi.org/10.1097/ALN.0000000000000558.

[5] Qian-Yi Peng, Xiao-Ting Wang, Li-Na Zhang & Chinese Critical Care Ultrasound Study Group (CCUSG). Findings of lung ultrasonography of novel corona virus pneumonia during the 2019–2020 epidemic. 12 March 2020 Intensive Care Medicine.

[6]  Chan JF, Yuan S, Kok KH, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet 2020.

[7] Chest CT Findings in Cases from the Cruise Ship “Diamond Princess” with Coronavirus Disease 2019 (COVID-19)

[8] Radiographic and CT Features of Viral Pneumonia Hyun Jung Koo, Soyeoun Lim, Jooae Choe, Sang-Ho Choi, Heungsup Sung, and Kyung-Hyun Do RadioGraphics 2018 38:3, 719-739 doi: https://doi.org/10.1148/rg.2018170048

[9]  WHO – Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected.

[10] Safe Airway Society. Consensus Statement: Safe Airway Society Principles of Airway management and Tracheal Intubation Specific to the COVID-19 Adult Patient Group. MJA 2020.

[11] GUAN WJ, Ni ZY, Hu Y, Liang WH, et al  Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020 Feb 28. doi: 10.1056/NEJMoa2002032

[12] Tao Ai et al. Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases. Radiology, published online February 26, 2020; doi: 10.1148/radiol.2020200642

Goals in Mechanical Ventilation: Concepts for the Students

Goals in Mechanical Ventilation: Concepts for the Students
Authors: Dr. Job Heriberto Rodríguez Guillén (@job_rdz), Dr. Sergio Edgar Zamora Gómez (@ezg_galeno)


Mechanical ventilation (MV) is one of the cornerstones of life support in the emergency department. It provides time for establishing therapeutic management aimed at the triggering cause of injury until the patient improves physiologic balance (1). Therefore, MV can not be a unique and specific treatment for any disease by itself; but it has two general and fundamental goals: to support the injured lung and protect the healthy lung.

Set your goals: Support and Protect


MV supports the respiratory system; meanwhile, the primary disease becomes under control.

Example: A patient with acute respiratory distress syndrome (ARDS) due to pneumonia, where MV provides support to improve gas exchange and reduce work of breathing (WOB) meanwhile antibiotic treatment induces remission of the infectious disease.


MV is aimed to avoid complications not related to the primary disease. The patient-ventilator relationship becomes of benefit for the patient as his respiratory function is in the risk of injury because the primary disease does not allow him to breathe properly or because therapeutic interventions can reduce protective airway reflexes and lead to respiratory complications.

Example: Patients presenting neuromuscular diseases (Guillain-Barre syndrome), diseases affecting bulbar muscles (myasthenic crisis), decreased consciousness (stroke, poisoning) or severe traumatic brain injury, all these without lung injury at first but in high risk of pneumonitis and pneumonia due to aspiration of gastric content.

Goals of Mechanical Ventilation
Mechanical ventilation has two general and fundamental goals: to support the injured lung and protect the healthy lung.

Specific goals of mechanical ventilation

One of the specific objectives of MV is to promote the optimization of arterial blood gases levels and acid-base balance by providing oxygen and eliminating carbon dioxide (ventilation). MV can reduce the work of breathing by taking effort from respiratory muscles and maintaining the long-term respiratory support for patients with chronic diseases.

MV´s circle (2) begins by recognizing the patient´s need for mechanical ventilatory support. Intubation and ventilation decision making is an essential skill for emergency physicians. Consideration of the patient´s needs is the basis of this decision making. The main indications for intubation and mechanical ventilation are (3):

  1. Refractory hypoxemia
  2. Increased respiratory effort
  3. Apnea/hypopnea leading to inadequate ventilation (Hypercapnia)
  4. The inability for airway protection

The goals should be individualized and established according to the clinical situation that led the patient to required ventilatory support. Although standard criteria traditionally have been specified for the onset of MV (3), we must remember that indication for intubation and ventilation is an essential skill for every physician treating critical care patients and the key is just thinking about what the patient needs.

Standard criteria for starting mechanical ventilation
Acute Ventilatory Failure
pCO2 > 50 mmHg + pH < 7.30
Impending Ventilatory Failure
Maintains normal gasometric levels by increasing respiratory effort.
Severe Hypoxemia
pO2 < 60 mmHg + FiO2 > 50%

pCO2 and pO2 values at sea level

In general, we can encompass the specific objectives of MV in three fundamental principles that must be fulfilled in every patient by setting the goals according to the primary disease:

  1. Improve oxygenation (O2) and ventilation (CO2)
  2. Reduce respiratory effort
  3. Minimize ventilator-induced lung injury (VILI)


The goals of MV are established based on the primary disease that led the patient to need MV support, under the concept of protecting and supporting the lungs. Primum non nocere; lung-protective ventilation should be initiated in all patients who need it.

References and Further Reading

  1. Frank Lodeserto MD, “Simplifying Mechanical Ventilation – Part I: Types of Breaths”, REBEL EM blog, March 8, 2018. Available at: https://rebelem.com/simplifying-mechanical-ventilation-part/.
  2. Frank Lodeserto MD, “Simplifying Mechanical Ventilation – Part 2: Goals of Mechanical Ventilation & Factors Controlling Oxygenation and Ventilation”, REBEL EM blog, May 18, 2018. Available at: https://rebelem.com/simplifying-mechanical-ventilation-part-2-goals-of-mechanical-ventilation-factors-controlling-oxygenation-and-ventilation/.
  3. Scott Weingart. EMCrit Lecture – Dominating the Vent: Part I. EMCrit Blog. Published on May 24, 2010. Accessed on August 30th 2019. Available at [https://emcrit.org/emcrit/vent-part-1/ ].
Cite this article as: Job Guillen, Mexico, "Goals in Mechanical Ventilation: Concepts for the Students," in International Emergency Medicine Education Project, September 2, 2019, https://iem-student.org/2019/09/02/goals-in-mechanical-ventilation-concepts-for-the-students/, date accessed: November 25, 2020