Last year’s COVID-19 wave was all about roti, kapda, makaan (food, clothes, shelter) – the basics, we thought then. This year's intense second wave is making us gasp for breath with a shortage in medical oxygen to treat the critical COVID-19 infected. Doctors tell us everything we need to know about oxygen – the pranavaayu, that keeps us up and about from the baby gasp (the first breath of a new born within 10 seconds of birth) to the agonal gasp (the last breath before death).
Our body on oxygen
"Oxygen fuels our living processes. It contracts our muscles, helps our cells to work, grow and regenerate, feeds our brains, calms our nerves, helps the heart to pump, cleanses the body of toxins, fights infection and boosts immunity," says Dr Narendra Nath Jena, Director, Institute of Emergency Medicine, Meenakshi Mission Hospital & Research Centre, Madurai.
Once air enters the nose or mouth, it gets humidified and reaches the alveoli, tiny air sacs that help to pull in oxygen and transfer it into the blood stream and also to pull out the carbon di oxide and push it out of the lungs and back up to breathe out. COVID-19 destroys these alveoli by thickening the walls so gas exchange becomes difficult. Liquid (mostly inflamed cells and protein) then fills up between the alveoli, further hindering breathing.
- 21% The amount of oxygen in the atmosphere
- 2,000 litres The amount of oxygen that goes into body of a healthy person every 24 hours.
- 90% The percentage of energy our body derives from oxygen; only 10% comes from food and fluid
Oxygen does piggy-back ride on the red blood cells (RBCs) by binding to the haemoglobin (Hb), the protein in each cell, and flows through the body to reach the vital organs, brains, tissues and cells. If you are anaemic, that is your Hb count is low, chances are your organs might receive less oxygen due to the decreased affinity of haemoglobin for the orygen.
The left side of your heart receives oxygen-rich blood from your lungs and pumps it through your arteries to the rest of your body. The right side of your heart receives oxygen-poor blood from your veins and pumps it to your lungs, where it gets rid of the carbon di oxide and picks up oxygen. In COVID-19, an increase in oxygen demand occurs because of compromised lungs and fear (that excites the body). This may lead to heart damage, especially if the arteries were already clogged.
The ideal diet
A diet rich in iron and vitamins helps keep our immune system strong. Foods such as broccoli, soy beans, red kidney beans, chicken, walnuts, citrus fruits, green beans, carrots help push the iron content and our haemoglobin levels and in turn uptake of oxygen. Dietary nitrates from spinach and other leafy greens, beetroot and berries help the blood vessels relax and lead to better circulation of blood and oxygen in the body, says Dr Anam Golandaz, Mumbai-based clinical dietician and consultant, Masina Hospital.
What is it?
The oxygen saturation level (also known as SPO2) stands for serum (S) pressure (P) and oxygen (O2). In most people, the body needs a minimum of 95% of oxygen in the blood to function ably. When oxygen deprived, it goes into emergency: the heart’s rhythm escalates, increasing the risk of acute pulmonary cardiac arrest, there’s brain-to-body dysfunction causing restlessness, disorientation, confusion and dizziness. A doctor needs to take a call on whether you should get started on supplemental oxygen, what duration it should be given for, and at what saturation level.
A healthy body is naturally capable of adapting to varying saturation levels. For instance, when mountaineers go scaling peaks, their bodies get acclimatized to the low oxygen level at high altitudes. The threshold is different in each person. Somebody with SPO2 between 88-94 may not show any breathing problems while somebody with a reading of 93 can be gasping for breath. Low oxygen saturation in the blood without any visible manifestation of distress is called happy hypoxemia.
When there is any physiological stress ranging from short-term infection (like the flu) or long term disease (like diabetes), or life changes like menopause or poor nutrition, the body's demand for oxygen increases because there is a drop in the count of RBCs that are otherwise required to carry enough oxygen to the different organs.
With COVID being a disease of the lungs, things are complicated. The coronavirus invades the body when we breathe it in (from another infected person nearby) and infects the cells lining the throat, airways and lungs. So, if your lungs are not in a great condition, say if you smoke, you are standing on the edge.
Even as our internal warriors, the white blood cells naturally try to fight respiratory tract infection, disease manifests in swelling and inflammation of the lungs and constriction of the airways. The air sacs get filled with mucus and make it harder for the body to take in oxygen. This leads to an abnormal rate of breathing -- either too fast or too slow, shortness of breath or difficulty in breathing.
- Dr. Lancelot Pinto, Consultant Pulmonologist, P D Hinduja Hospital, Mumbai
Devices to remember
The non-invasive device enables easy reading of SPO2. Earlier used only in health centres, COVID has turned it into a household item. Rest your hand on a flat surface and clip the stapler-like gadget on the right middle finger (or forefinger or thumb in that order). Using light sensors, the device records the percentage of oxygen in blood flowing through the body. The percentage is displayed on the screen and a reading between 94% and 100% for all age groups is safe.
The reading can be taken anytime of the day. Even one low reading below 94% requires a doctor's intervention. Just to be sure rub and warm your hands before the second reading or measure your SPO2 level with two different pulse oximeters successively. Always check on clean nail bed. Readings with artificial nails or any nail paint or colour on the surface could show error readings.
Smart wearables like the Fitbit or Apple watch, doctors remind, are fitness devices and the readings recorded by these devices may not be reliable.
These contain highly pure oxygen with no contamination and require refilling because finite amount of oxygen is compressed in the cylinder and is inhaled by the user as long as it lasts. The cylinders come in different sizes and can be purchased against medical prescription only and are used as first aid resuscitation for emergencies and life support for those who find difficulty in breathing.
A doctor’s approval is needed because caregivers should know how much oxygen flow is required per minute, based on the dip in 02 levels, the type of infection, the extent of damage to the lungs and other co-morbidities such as hypertension, diabetes.
Do remember: supplemental oxygen is a drug
A device that captures and filters the ambient air and instantly generates medical grade oxygen at an infinite supply so long as the battery that powers it are charged. So while the concentrator requires no refilling, it needs continuous supply of electricity.
Concentrators can be used only on approval and is suitable for moderately affected individuals with O2 saturation levels of 85 %. These handy devices come in sizes to supply one to 10 litres of oxygen per minute and are not advisable for ICU patients who require more oxygen.
Medical advise is necessary to know whether oxygen is to be given 24 hours or only on exertion, as there is a risk of hypoxemia (too low oxygen levels – below 90% on a pulse oximeter) causing further damage to the already incapacitated lungs. Also, any overdose of self-administered oxygen may cause harm (even death) to those with Chronic Obstructive Pulmonary Disease (COPD).
In use for critical care, they are computerized microprocessor-controlled machines, that come in invasive and non-invasive variants. Used mainly in intensive care units and emergency wards, the non-invasive ventilation is required when a patient is sleeping. It employs a simple hand operated bag valve nasal mask.
Invasive methods are required for long-term dependence, with either nasal or trachea intubation (insertion of a tube through the nose or mouth to the airway) . The machine pumps air with extra oxygen into the patient's airways when they are unable to breathe on their own. Other than when the lung functioning is severely impaired either due to injury or illness such as COVID, ventilators are also used to support breathing during any surgery.
- Dr. Sundeep Salvi