The Malaysian Insight

SILENT hypoxia, identified as one of the main reasons for severe Covid-19 cases among younger patients, can be avoided if the symptoms are discovered early, said a medical expert.

Associate Prof Dr Tan Toh Leong, an emergency physician consultant with Hospital Canselor Tuanku Muhriz UKM, said silent hypoxia is a condition that occurs when oxygen level in the blood falls to below 94%. Lethargy is one of the main tell-tale signs.

The Ministry of Health said last week that there was a 35% increase in Category 4 and 5 patients who were severely ill with Covid-19, with “happy hypoxia” being one of the reasons.

The proper medical term for the condition is silent hypoxia, but it is also known as happy hypoxia.

Tan said despite the notion that silent hypoxia happens out of the blue with no apparent clear symptoms, one could spot the red flags if they paid close attention to the signs.

A Category 4 Covid-19 infection refers to a patient suffering from symptoms of pneumonia and is given oxygen support while a Category 5 patient shares the same condition along with multi-organ failures.

The ministry said among those who were brought into the hospital seriously ill were young and healthy asymptomatic patients who were unknowingly suffering from low oxygen levels.

“They would be tired. They would want to conserve the remaining oxygen concentration in the body,” he said.

Tan said normal oxygen saturation for the body would be around 98% to 100% and if the oxygen level falls below 94%, it is then considered a health hazard and immediate medical attention is required.

“We call oxygen saturation at 91% the ICU point, everything below this point needs immediate oxygen therapy and intervention,” he said.

He said some Covid-19 patients arrived at the hospital with their oxygen levels at 50-60%. “They are as good as gasping for air silently (nyawa-nyawa ikan),” he said.

“Silent hypoxia happens in people who are fatigued after a prolonged infection, not only with Covid-19 but even pneumonia,” said Tan who is also the president of the Malaysian Sepsis Alliance.

Silent hypoxia is common in lung infections such as atypical pneumonia and is not unique to Covid-19.

Although the MoH said the condition was detected in young and healthy asymptomatic Covid-19 patients, Tan said silent hypoxia was more common in the elderly and those who have chronic diseases.

The condition is predominantly found in people with diseases linked to malnourishment, such as cancer, obesity and uncontrolled diabetes. He added that Covid-19 could also lead to malnourishment due to the loss of smell and taste.

“It develops slowly over a long time. Covid-19 won’t kill you today but it slowly develops.

“How Covid-19 happens is that the lung will slowly be impaired and the body will adapt until it hits the lowest point.”

Patients become tired after hyperventilating or breathing rapidly for a duration as they fight the infection over a period of time.

The fatigue that ensues eventually slows down the breathing and sends them into a hypoventilation (slow breathing) mode even though they might be in a state of great hypoxic distress.

Tan, however, said it is possible for a common medical practitioner or doctor to not consider lethargy as a sign of infection.

“Tiredness for us is a red flag. Malaise and lethargy are the first signs of happy or silent hypoxia,” said the doctor who treats infectious diseases.

He advised that it is important to check the oxygen levels in elderly patients if they feel tired and lack energy.

On the use of oximeters, Tan said while it is good to have it on hand, one should know how to use it. He said misreading could happen if one is not familiar with using the device.

The lack of appetite is another red flag, said Tan.

He said if food and water intake is less than 80% from the patient’s normal diet, then it is important to seek medical attention.

“You have to see whether they are too tired and lethargic to get out of the bed or go to the toilet,” he said.

Another way to monitor is to observe the breathing of a person within a minute. He said ideally a person should be able to take between 12 and 20 breaths within a minute.

“If less than 12 or more than 20, then they have to seek medical care. If more than 20 it is called rapid breathing, and it commonly happens in hypoxic patients. If the hypoxic patient is not breathing rapidly, this is called silent hypoxia. They could be ill,” he said.

Tan added that dead-on-arrival cases might be happening due to silent hypoxia as well. – June 23, 2021.