Oxygen is a drug, and it is being used regularly to treat patients everywhere. In general, any patient comes with Acute Asthma, Respiratory distress, Heart failure, Severe pneumonia, Bronchiolitis, Myocardial infarction, Diabetic ketoacidosis, Status Epilepsy, acute poisoning etc., we first give oxygen therapy by cannula or mask and it helps a lot to the patients to make their breath easier and spontaneously they feel better.

During the last COVID-19 episode, we learned the value of oxygen. Unfortunately, there was a crisis of oxygen worldwide in the COVID-19 pandemic situation. In Bangladesh, India and elsewhere, many COVID-19 patients died because of oxygen scarcity.

The air we breathe is about 78% nitrogen, 21% oxygen and 1% other gases, including carbon dioxide. But the concentration of medical oxygen in a cylinder is around 95-99%. So, while giving oxygen by cannula or mask, it mix-up with air and attention comes down to about 95-96%. Oxygen can be given to a patient by cannula, mask, headbox, high flow nasal cannula and by the ventilator.

Every drug has some toxicity and oxygen therapy also has much toxicity if not given properly. If oxygen is provided for a prolonged time in a high concentration may damage the lungs, retina, may produce encephalopathy and subsequently affect other organs like the liver, kidney, heart etc. and eventually may lead to death.

It may cause alveolar damage, collapse of lungs and breathing difficulty in the lungs. There may be retinal detachment, especially in preterm low birth weight newborns may cause blindness, which we call Retinopathy of prematurity (ROP). There may be convulsion and impaired consciousness in the central nervous system affection. There may be hemolysis, acute kidney injury and hepatocellular damage. Sometimes the death may occur. So, oxygen saves a life, but indiscriminate use may cause death.

We all became familiar with the pulse oximeter and its use. With this simple instrument, we can measure our oxygen saturation instantly. The normal value is 90-100. But less than 90 indicates there is less oxygen in the blood, so oxygen is to be given. It can also be measured by arterial blood gas analysis, usually done in ICU patients. So to avoid oxygen toxicity, oxygen is to be delivered, in the right amount, in the right indication and in the right duration in the right way by the right person.

Be happy and healthy now and always.

The author is a Professor of Paediatrics at Community Based Medical College (CBMC), Mymensingh.
E-mail: mmukkhan@gmail.com