COVID-19 is a worldwide pandemic involving the vast spread of a type of viruses called the Corona virus. These viruses are positive-stranded RNA viruses having a crown-like appearance when viewed an electron microscope. It belongs to the subfamily Orthocoronavirinae of the Coronaviridae family (order Nidovirales) and is divided into four genera of CoVs: Alphacoronavirus (alphaCoV), Betacoronavirus (betaCoV), Deltacoronavirus (deltaCoV), and Gammacoronavirus (gammaCoV). Then, the betaCoV genus divides into five sub-genera. Genomic studies have proven that bats and rodents are the gene sources of alphaCoVs and betaCoVs. On the other hand, avian species is the gene sources of deltaCoVs and gammaCoVs. This large family of viruses causes respiratory, enteric, hepatic, and neurological diseases in different species, like camels, cattle, cats, and bats. Seven viruses have been shown infecting humans (HCoVs) and these include HCoV-OC43, and HCoV-HKU1 (betaCoVs of the A lineage); HCoV-229E, and HCoV-NL63 (alphaCoVs). These human coronaviruses can lead to common colds and respiratory infections in immunocompetent individuals and the elderly.
Other human corona viruses like SARS-CoV, SARS-CoV-2, and MERS-CoV (betaCoVs of the B and C lineage can lead to respiratory problems with different clinical severity
Transmission
Like any other respiratory pathogen, it is transmitted through respiratory droplets from coughing and sneezing. Aerosol transmission is possible too.
Symptoms
Early symptoms include:
A. Fever
B. Dry cough
C. Fatigue
The virus can cause to pneumonia, respiratory failure, septic shock, and death. Severe symptoms include:
A. Problem breathing or shortness of breath
B. chest pain or pressure
C. New confusion
D. Bluish lips or face
Symptoms can show up in 2 days or to 14 varying from person to person.
Most common symptoms are:
A. Fever 83%-99%
B. Cough 59%-82%
C. Fatigue 44%-70%
D. Lack of appetite 40%-84%
E. Shortness of breath 31%-40%
F. Mucus/phlegm 28%-33%
G. Body aches 11%-35%
Risk Factors
Anyone can get COVID-19. Most infections are mild, especially in children and young adults and people over 65 are most likely to get a serious illness. So, age is an important factor in determining the severity of the disease. In addition, some manifestations increase the severity of the corona symptoms if present. This includes:
A. Moderate to severe asthma
B. Heart, lung, or liver disease
C. Severe obesity
D. Diabetes
E. Kidney disease that needs dialysis
Disease severity
The severity of the respiratory illnes is divided into categories.
Uncomplicated (mild) Illness
Most patients usually present with symptoms of an upper respiratory tract viral infection, including mild fever, cough (dry), sore throat, nasal congestion, malaise, headache, muscle pain, or malaise. Signs and symptoms of a more serious disease, such as dyspnea, are not present.
Moderate Pneumonia
Respiratory symptoms such as cough and shortness of breath (or tachypnea in children) are present without signs of severe pneumonia.
Severe Pneumonia
Fever is present with severe dyspnea, respiratory distress, tachypnea, and hypoxia.
Acute Respiratory Distress Syndrome (ARDS)
This syndrome is a form of a severe respiratory failure
Treatment and Management
There is no definite cure for corona so what is done recently is to give symptomatic treatment where symptoms are being controlled. This involves treating any infection present alongside the virus, and controls the respiratory illness and maintaining appropriate breathing. Oxygen therapy is the major treatment intervention for patients with severe infection and mechanical ventilation is important in cases of respiratory failure.
Ventilation
To maintain vital signs, artificial breathing is implemented in severely diseased patients. This is done using a ventilator. Simply, a ventilator works by pushing oxygenated air into the lungs at positive pressure and displaces fluid from the pulmonary alveoli, which the exchange of oxygen and carbon dioxide molecules to and from the bloodstream occurs.
Ventilator settings include:
Tidal volume is set low, ideally at ≤6 mL/kg predicted body weight (PBW) typically using a volume-control mode setting and an inspiratory: expiratory (I:E) ratio of 1:2.
Set stating respiratory rate (RR) to between 14 to 22 breaths per minute (bpm), but not to exceed 35 bpm.
Maintain the peripheral arterial oxygen saturation (SpO2) at 92 to 96 percent.
Need for long-term mummification and warming of inspired gases is provided by a heat and moisture exchange filter (HMEF) placed at the endotracheal tube connection to the breathing circuit
The need to manage condensed water accumulation in the breathing circuit so condensers and water traps are added.
Monitoring long-term ventilation goals for maintaining adequate oxygenation with maintenance of Pplat ≤30 cm H2O in patients with COVID-19 ARDS
Confirmation that there is no leak around the endotracheal tube cuff
Parameters to be monitored:
Inspired oxygen concentration
Inspired and expired carbon dioxide (CO2)
Inspiratory pressure
Tidal volume
Risks of Ventilators
Possible risks include:
Further infection
Collapsed lung (pneumothorax where a part ofthe lung can become weak
The pressure of putting air into the lungs with a ventilator can damage the lungs.
Conclusion
COVID-19 is becoming a serious disease outbreak. Having no cure makes it hard to combat this disease. Respiratory failure and respiratory complications in the sever stages of the disease propose a high risk that may lead to death. Ventilators form a critical intervention in trying to control and maintain respiration.
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