Dr Pham Van Phuc, who works at the National Hospital for Tropical Diseases' intensive care unit in Hanoi, said his department has received five critically ill Covid-19 patients who need ventilators.

The patients arrived at the hospital with respiratory distress and require high levels of oxygen intake through ventilators. Then emergency room (ER) doctors treat patients with a combination of antiviral drugs.

Depending on the respiratory condition of a patient, doctors use various treatment protocols. Mild cases are treated for the symptoms and provided nutrients for health improvement. Severe cases could require oxygen therapy with oxygen masks and cannulas.

If this does not work, doctors pump up the oxygen levels and resort to non-invasive mechanical ventilation. If the patient does not respond, they are transferred to the intensive care unit where doctors intubate them and put them on a ventilator.

Using extracorporeal membrane oxygenation (ECMO), which involves pumping blood out of the body and to a heart-lung machine that removes carbon dioxide and sends oxygen-filled blood back, is the last option.

"There are patients who need a breathing tube and intubation right at the emergency department," Dr Phuc said. "There are also those who need it when they arrive at the intensive care unit."

Endotracheal intubation is a high-risk technique that poses a risk of infections to doctors since they are exposed to aerosol dust generated by the procedure.

There is less risk in using ECMO, but it is a high-tech method that requires a team of specialized doctors.

On top of antiviral drugs, doctors also have to perform resuscitation and use various drugs to maintain body functions.

Covid-19 patients in critical condition often experience bacterial infections, and so antibiotics are often added.

Dr Phuc said the selection of antiviral drugs is a complicated issue and there is no consistency when it comes to antiviral drug protocols for critically ill patients. So doctors have had to refer to many studies, especially those done by doctors in China where the pandemic first broke out and others published in globally reputed medical journals.

For instance, initially, based on the Chinese regimen and Vietnamese research, Covid-19 treatment involved a drug used to treat HIV.

All medicines have varying degrees of efficacy but also side effects. The HIV drug for instance causes nausea, diarrhea and fatigue among other things. If the side effects become serious, the medication has to be stopped immediately.

Patients in intensive care are mostly older people or have underlying conditions, and so all their organs must be screened and the conditions treated.

The professional committee at the hospital has to work on every detail for each individual to come up with an appropriate treatment protocol.

Patient 20, a 64-year-old Hanoi woman, is a severe case. She had pneumonia and her health was failing when she was first admitted to the hospital. She responded very slowly to treatment and her lung lesions worsened, and she was put on a ventilator but did not improve. So doctors decided to put her on ECMO.

A British patient, 74, who was discharged from the National Hospital for Tropical Diseases on April 14, has blood cancer. The hospital spoke with his doctor in England to find out about his condition and if he was on medication.

"In addition to antibiotics and antiviral drugs for Covid-19 treatment, we combine a variety of other drugs to treat underlying medical conditions besides adjuvants, anticoagulants, etc.," Phuc said.

"We have to select suitable drugs while also minimizing side effects and mitigating harmful interactions between the various drugs."

Dr Phuc said one of the problems facing Covid-19 patients is blood coagulation disorders which clog veins and lead to multi-organ damage. "Almost all organs like the heart, lungs, kidneys, liver, brain are affected, and screening is complicated."

"The greatest difficulty in treating critical patients is that currently there is no specific protocol anywhere in the world. So patients in serious condition could die without appropriate treatment," he added.

Currently the intensive care unit at the hospital has two critically ill Covid-19 patients.

Of Vietnam’s 270 cases so far, 230 people have recovered and no deaths recorded. The country has gone two days without a new case as of Sunday evening.

No new cases of community transmission have been recorded over the past 10 days, according to the Health Ministry.