Ventilators? Respirators? Ventilation? Respiration?
As we progress through the COVID pandemic, there are many medical terms being thrown around. Some of these terms sound similar and can be very confusing. Perhaps readers may have heard the terms ventilation and respiration, but also ventilators and respirators.
The first two terms apply to how the heart and lungs work together in providing oxygen to the cells within the body. The second two terms apply to methods in which we can transport oxygen or carbon dioxide to patients.
The terms ventilators and respirators apply to devices that protect individuals, including healthcare providers.
Respirators such as the N95 mask are tight-fitting masks that block 95% of airborne particles from reaching one’s lungs. Powered air-purifying respirators, PAPRS, block particulates, gases, and other hazards via powered filtration. Unfortunately, the devices can be quite costly.
Manual and mechanical ventilators
Ventilators remove carbon dioxide and other waste products from every cell. If oxygen is not provided to brain cells for greater than six minutes, brain damage and death may occur.
A ventilator performs the act of ventilation by moving a gas in and out of the lungs. It can be performed by an automated machine or by a provider squeezing a bag connected to the patient. Most commonly, air with a high concentration of oxygen, similar to the air around us, is used as the gas that is given to the patient.
When the lungs’ alveoli are blocked or pulmonary blood flow decreases dramatically, respiration can be halted. A blocked state often occurs when individuals have pneumonia. Secretions (phlegm) cause the blockage at the alveoli level.
The level of blockage, and thus the extent of the pneumonia, determines how sick an individual may become. Pneumonia can halt respiration so much so that the heart and other-organs cannot obtain the oxygen they need to function. This is why we sometimes need mechanical ventilators.
In many illnesses where the lungs or circulatory system are damaged, including COVID-19-related sickness, respiration cannot occur without assistance. This assistance is provided by a variety of methods that include ventilators.
To effectively deliver gases further down into the lungs, a breathing tube (endotracheal tube) may be placed in the trachea (wind pipe). The act of placing this tube is known as intubation. After being intubated, patients are usually placed on mechanical ventilators.
Unfortunately, mechanical ventilation can’t always improve respiration enough to provide adequate provision of oxygen or removal of carbon dioxide.
The ventilator can be programmed to adjust the amount of gas provided or the amount of time the various gases have to exchange. The patient’s own neural respiratory cells can also drive what is done for ventilation and what the subsequent respiration is. Sometimes extreme pressure or a very quick rate of ventilation is required for adequate gas exchange.
The COVID-19 virus has barb-like projections that are thought to damage the lung surfaces. This damage can make the spongy lung tissue very stiff. Sometimes in the critically ill, as lung damage progresses making it stiffer and stiffer, no amount of pressure or time can provide adequate gas exchange.
Also as the body fights the virus, secretions occur to block further viruses or bacteria from getting in to the lungs. This defense mechanism often does more damage than good.
There is much more to discuss regarding machine ventilation in the critically ill, but the key during this pandemic is avoiding having to be on a ventilator in the first place. The things you can control are listening to the CDC guidelines and following the social distancing and hand-washing recommendations.
If a patient does require a ventilator, know that all is not lost. Your healthcare providers will do their best using the mechanical ventilators and medications to assist your body’s respiration while critically ill.