What role do ventilators play in treating COVID-19?

It is important to note that the information provided in this Series is intended for your general knowledge only and is not a substitute for professional medical advice or treatment.

As the epidemic continues to spread, the world has witnessed rapidly rising demands and a widening supply gap of ventilators. Including the United States, Italy, the United Kingdom and Spain, countries with a large number of confirmed cases have been struggling to meet their demands by purchasing globally and expanding production domestically. Why are ventilators so critical in the treatment of COVID-19 patients?

Breathing difficulties are one of the clinical symptoms of severe COVID-19 patients. When the new coronavirus attacks patients' lungs, complications such as pneumonia and Acute Respiratory Distress Syndrome (ARDS) may occur. According to the Clinical Guidance for COVID-19 Pneumonia Diagnosis and Treatment (7th edition) released by the Chinese National Health Commission (NHC), in severe cases, patients present dyspnea and/or hypoxemia within one week after onset and some of them may rapidly deteriorate to ARDS. The World Health Organization (WHO) estimated that about 13 percent of confirmed cases turned critically ill and could have breathing difficulties. In such cases, using instruments to support or replace breathing is the only solution.

Ventilators are vital medical devices in improving human respiratory function. During the process of inhalation, lung volume increases and alveoli expands as a result of the contraction of respiratory muscles. Then inhalation occurs because of the pressure gradient between atmosphere and thoracic cavity. In contrast, during exhalation, respiratory muscles relax and alveoli contracts. Then exhalation happens due to increased pressure within the thoracic cavity. When patients encounter breathing difficulties, ventilators can help achieve the pressure gradient, thus replacing, controlling or changing patients' breathing. Ventilators can be divided into two categories. In non-invasive ventilation, patients receive breathing support through a face mask, nasal mask or a helmet. If the condition does not improve or gets worse, tracheal intubation and invasive mechanical ventilation should be performed timely.

Ventilators play a significant role in reducing the fatality rate of COVID-19. To date, there is still no "wonder drug" in the treatment of COVID-19 patients. Therefore, when severe and critically severe patients have symptoms of respiratory difficulty or failure, using ventilators to assist breathing and ensure oxygen supply to brain and organs lays the basis for follow-up treatment. Given the important role of ventilators in  reducing fatality rate, NHC has announced mechanical ventilation as one of the major methods in the treatment of COVID-19 patients.

Additionally, several points are worth noting in the use of ventilators to provide breathing support for COVID-19 patients. For more details, please refer to How to use ventilators to effectively support severe or critically severe patients.

References:

[1] The Chinese National Health Commission, State Administration of Traditional Chinese Medicine. Clinical Guidance for COVID-19 Pneumonia Diagnosis and Treatment (7th edition).http://www.nhc.gov.cn/yzygj/s7653p/202003/46c9294a7dfe4cef80dc7f5912eb1989.shtml

[2] Coronavirus: What are Ventilators and Why are they important?, https://www.bbc.com/news/health-52036948

[3] https://courses.lumenlearning.com/boundless-biology/chapter/breathing/

[4] http://www.chinanews.com/cj/2020/03-30/9141614.shtml

[5] http://news.sina.com.cn/c/2020-04-03/doc-iimxyqwa4986131.shtml

Author: Yu Lu,Center for International Knowledge on Development