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OXYGEN THERAPY -THE ESSENTIAL MEDICINE FOR FAILING LUNGS!!
- Bharat Chukka
- Oct 18
- 6 min read
Updated: Oct 19
Oxygen therapy is a vital treatment for lung health.
Oxygen is indispensable for the survival of all living beings on the earth. Example: human beings, animals and plants. The oxygen which is present in the atmospheric air at 21% concentration is inhaled into the lungs during respiration. It dissolves in the blood that flows through the lungs and reaches heart . From heart O2 reaches all the organs and tissues in the human body. Therefore respiration and circulation are crucial for the functions all vital organs like brain, kidney, liver and heart. Any pulmonary disease which impairs the oxygen intake or distribution into blood is a threat to human organs. In such conditions supplementation of oxygen or OXYGEN THERAPY is imperative for the vitality of the tissues. Oxygen is a DRUG which needs to be prescribed at accurate dose, through a sutiable device and for optimal duration.
ANCIENT HINDU CONCEPT OF OXYGEN :
Charaka and Sushruta, the two famous ancient physicians / surgeons recognized a 'PRANAVAYU' that is 'LIFE AIR'. Charaka stated that chest, head, ears, tongue, mouth and nose are the seat of PRANAVAYU which implies OXYGEN. In modern medicine it was Joseph Priestley in 1772, who isolated oxygen by heating Mercuric oxide.
The recent COVID 19 pandemic made OXYGEN a house hold name. The importance and precious nature of oxygen during the second wave of COVID 19 in 2021 was recognized by all and it came to be known as LIFE SAVING DRUG.
WHAT IS OXYGEN THERAPY?
Oxygen therapy is a critical treatment in which oxygen is supplemented from an external source in conditions of HYPOXIA (low oxygen content in the body). The supplementation makes lungs ensure that all vital organs and tissues receive oxygen so that they can function normally.
OXYGEN THERAPY CAN BE DIVIDED INTO TWO TYPES :
1. EMERGENCY oxygen therapy (Short Term)
2. HOME / DOMICILIARY / LTOT oxygen therapy (Long Term)
1. EMERGENCY oxygen therapy : is required in both pulmonary emergencies and non pulmonay emergencies where there is HYPOXIA . (Hypoxia is low levels of oxygen in the body.)
The examples of PULMONARY emergencies are Acute exacerbation of COPD, Acute Severe Asthma, Severe Pneumonia (Bacterial, Viral eg. COVID 19 and Influenza) Aspiration Pneumonia, Pulmonary Embolism ( clot in blood vessels of lung), ARDS (Acute Respiratory Distress Syndrome). These conditions are associated with hypoxia and RESPIRATORY FAILURE.
HYPOXIA detection:
Oxygen level in peripheral blood is indicated by Pulse Oximetry ie, SpO2 (Peripheral O2 Saturation). Normal SpO2 is 95%. Supplementary oxygen is initiated if patient's SpO2 falls to < 94%. It is prudent to target SpO2 between 92 to 98%.
The NON PULMONARY emergencies with hypoxia requiring EMERGENCY Oxygen therapy are Shock, Sepsis, Cardiac arrest, CPR, Anaphylaxis, Obstetric emergencies, Acute Decompensated Heart Failure, Myocardial Infarction.
Other indications are during surgery and anaesthesia, endoscopic and interventional procedures, post operative complications and cluster headache.
INDISCRIMINATE USE OF OXYGEN IN SOME EMERGENCIES MAY ACTUALLY BE HARMFUL.(eg.Paraquat Poisoning, chronic COPD)
2.HOME / DOMICILIARY / LTOT ( Long Term) Oxygen Therapy:
is required in the following conditions with chronic hypoxia:
Stable chronic COPD patient with daytime resting hypoxia requires oxygen supplementation for atleast 15 hours in a day. The target SpO2 should be 88% to 92%.
Chronic progressive ILD
Severe chronic asthma
Other indications are Chronic Bronchiectasis, Destroyed lung, Chronic heart failure and Pulmonary vascular disease.
HOME OXYGEN THERAPY includes:
Nocturnal Oxygen Therapy (NOT) : During night hours due to hypoventilation ,oxygen is supplemented in conjunction with NIV or CPAP. eg. Obesity, OSA( Obstructive Sleep Apnea), NeuroMuscular Disease.
Ambulatory oxygen therapy (AOT): During activities like exercise and other daily activities, when the SpO2 falls.
Short burst oxygen therapy (SBOT) : indicated in cluster headache.
Palliative Oxygen Therapy (POT): In advanced or life limiting disease for relieving breathlessness.
OXYGEN THERAPY IN SPECIAL CIRCUMSTANCES:
Air travel
High altitude
Diving
Hyperbaric oxygen in pressurised chambers ( eg.decompression sickness, non healing wounds, tissue damage due to radiation)
HOW IS OXYGEN THERAPY DELIVERED? WHAT ARE THE DEVICES?
The normal O2 concentration in the atmospheric air we breathe is 21%. It is called FiO2 ( Fraction of Inspired Oxygen). This is responsible for our SpO2 to be maintained at 98% and PaO2 ( Partial Pressure of Arterial O2 ) at 80-100mm 0f Hg. In conditions of Hypoxia ( low O2 levels in body ) where SpO2 is <94% or PaO2 is <80mmHg due to Pulmonary or Non Pulmonary causes, O2 is supplemented with a suitable DEVICE and required FiO2, depending on severity of hypoxia and patient's needs. These devices are divided into LOW FLOW SYSTEMS and HIGH FLOW SYSTEMS.
LOW FLOW SYSTEMS:
Eg: Nasal prongs, Cannula and Cathters, Simple Face Mask, Breathing or Non Rebreathing Face Masks with Reservoir.
These devices provide O2 at a flow rate less than patient's inspiratory flow rate. FiO2 % is maintained by mixing of atmospheric air with O2. The Fi02 is generated depending on the type of device and flow rate.
LOW FLOW SYSTEM DEVICES:
DEVICE | FLOW RATE | FiO2 |
Nasal prongs, cannula | 1-6 lit/mt. | 24-44% |
Simple face mask | 5-10 lit/mt. | 21-50% |
Face mask with reservoir (partial rebreather) | 6-10 lit/mt | 40-80% |
Face mask with reservoir (non rebreather) | 10-20 lit/mt | 60-85% |
HIGH FLOW SYSTEM DEVICES
HIGH FLOW SYSTEMS:
These devices use a blender to deliver precise and fixed FiO2 at flow rates higher than the patients inspiratory flow rate.
HIGH FLOW SYSTEM DEVICES:
DEVICE | FLOW RATE | FiO2 |
Venturi mask | adjustable | 24-60% |
HFNC | upto 60 lit/mt | 21-100% |
Mechanical ventilator | adjustable | 21-100% |
Other devices like NIPPV, BIPAP and CPAP devices or modes are also high flow systems.
WHAT IS HFNC?
HFNC is High Flow Nasal Cannula equipment for oxygen therapy. This is a relatively recent innovate therapy that can deliver very high flow (30 - 60 liters per minute) of warm, humidified oxygen through nasal cannula. High and precise FIO2 can be delivered. This became popular and a house hold name during COVID pandemic when critically ill COVID patients with respiratory failure were treated with this device.
It helped in avoiding need for mechanical ventilation in many patients.
HOME / DOMICILIARY /LTOT OXYGEN THERAPY:
DEVICES AND SOURCES:
For Long Term Oxygen Therapy (LTOT) or home oxygen therapy the delivery devices are generally nasal prongs and face masks. Oxygen may be combined with NIV or CPAP in patients with Obesity, OSA etc. The sources of oxygen in home therapy are Compressed Gas Cylinders, Liquid Oxygen System and Oxygen Concentrator.
WHAT IS OXYGEN CONCENTRATOR?
An Oxygen concentrator is ideal for use at home because there is no need to fill the oxygen cylinders regularly. The concentrator filters out nitrogen molicules, water vapour and other gases in the atmospheric air and delivers concentrated oxygen to the patient. Though the initial cost is high ,running cost is negligible. There are many models of concentrators and the Pulmonologist/Chest physician selects a safe and effective model for the patient. It can deliver upto 90 % of oxygen at flow rates upto
5 lit/ per minute. Because it is an electrical device continuous power supply is needed. A backup source of oxygen supply like a compressed oxygen cylinder is necessary in case of power failure.
HOW DOES A PULMONOLOGIST/ CHEST PHYSICIAN PRESCRIBE HOME OXYGEN TO A PATIENT WITH CHRONIC RESPIRATORY DISEASE?
In Chronic respiratory diseases like COPD, chronic asthma, ILD and Pulmonary Hypertension, the PULMONOLOGIST will assess the stability of the patient, examines the ABG profile and prescribes suitable oxygen device, source and decides flow rate, FiO2, Target SpO2 and duration just like any "DRUG".
SAFETY TIPS FOR OXYGEN THERAPY:
Oxygen equipment should be away from flames and heat. Oxygen itself is not inflammable but helps fire to burn faster and spread.
Without pulmonologist's advice, oxygen flow rate / FiO2 should not be altered because too much or too little oxygen can lead to complications.
Secure storage of cylinders , clean hands and tubing regularly.
Avoid smoking near oxygen.
Oxygen therapy is SAFE when used as directed and it does not cause addiction.
If any side effects like skin irritation, head ache, confusion, gastric distention appear or symptoms worsen, a PULMONOLOGIST should be approached.
"OXYGEN THERAPY IS A CORNER STONE IN THE TREATMENT OF INDIVIDUALS WITH RESPIRATORY ILLNESS AND CONDITIONS THAT AFFECT OXYGENATION OF VITAL ORGANS.
BY OXYGEN SUPPLEMENTATION SYMPTOMS ARE ALLEVIATED, QUALITY OF LIFE IMPROVES, FUTURE COMPLICATIONS ARE PREVENTED."
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