An optimum amount of oxygen is essential for the functioning and survival of all body tissues and even a few minutes deprivation can prove fatal. When saturation level of oxygen in the body falls due to some respiratory illness or injury then we need to replenish it artificially to maintain an optimum level by giving oxygen therapy to the patient. This method of dealing with ‘respiratory failure’ was explained succinctly by Dr Girija Nair, Head Department of Pulmonary Medicine, Dr DY Patil Medical College, Mumbai on the 1st day of 20th NESCON, (20th National Conference On Environmental Sciences And Pulmonary Diseases), organized by the Academy of Respiratory Medicine in Mumbai under the auspices of Environmental Medical Association.
Oxygen therapy is one of the key treatments in respiratory care. This therapy is used to treat documented hypoxemia (as in case of smokers), severe respiratory distress, severe trauma, interstitial lung disease (ILD), chronic obstructive pulmonary disease (COPD) including chronicasthma and chronic bronchitis, pulmonary hypertension, acute myocardial infarction, and chronic lung patients during exercise. Some may need it for long term oxygen therapy at home (LTOT).
Before prescribing oxygen therapy there should be a clear indication of its need and the type of therapy needed. The doctor should list the purpose of the therapy, demonstrate the procedure and also list possible complications. For safe and effective treatment with this therapy, it should be remembered that the oxygen used in oxygen therapy is a prescription drug which is to be used under a doctor’s prescription and not like the oxygen we breathe naturally. The prescription should clearly state the air flow rate, delivery system, duration and instructions for monitoring. Regular evaluation of patient is necessary.
The basic purpose to ventilate patients through oxygen therapy is to improve gas exchange till lung functions improve. Oxygen saturation has to be within normal limits. Target should be pressure (PaO2) not less than 60mm Hg and SpO2 (saturation pressure) not less than 90mm Hg. Excess supply can do more harm than good and one should ensure that this does not happen. 100% Fi02 breathing is associated with decreased ventilation (obstruction) Dr. Nair shared her experience of having a tough time convincing the ICU staff to lower the oxygen flow while administering to patients of COPD requiring low flow oxygen, as COPD patients may worsen with high flow oxygen. Patients with chronic lung disease should never be delivered at more than 2-3 litre/minute oxygen .