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- ANESTHESIOLOGY IN THE TIME OF COVID - 22 Apr 2020
Can anesthesia machines be used as ICU ventilators for COVID-19 patients?
Yes, they can.
Every anesthesia machine has a ventilator attached to it. The ventilator is not as complex a device as what is found in the ICU, but an anesthesia machine ventilator is fully capable of ventilating sick COVID-19 patients, who have the severe pneumonia known as Acute Respiratory Distress Syndrome (ARDS). For years physician anesthesiologists have transported sick patients from the intensive care unit (ICU) to the operating room (OR) when patients needed a surgical procedure. These sick patients have been successfully maintained on the anesthesia machine ventilator, and physician anesthesiologists have attended to them.
The most practical way to utilize an anesthesia machine as a ventilator would be to convert the existing operating room into a temporary ICU in this time of the COVID-19 pandemic, when we face a threat of inadequate numbers of ICU beds and ventilators. Who would staff these additional temporary ICUs? It could possibly be the customary staff of the operating room, i.e. a circulating nurse and an anesthesiologist. Ideally there would need to be consultation and care by a critical care attending physician, to make sure the proper management is applied to all of a patient’s physiologic systems, e.g. their heart, kidneys, lungs, their antibiotics and their nutrition.
The American Society of Anesthesiologists (ASA) held an online Town Hall meeting last Thursday night, March 19th, 2020 to discuss anesthesiology information pertaining to the COVID-19 pandemic. The question of using anesthesia machines for ICU ventilators was specifically discussed. ASA President Dr. Mary Dale Peterson said she’d already participated in a conference call with government leadership, including President Trump, regarding the pandemic. She said she’d suggested the use of anesthesia machines as ventilators for COVID-19 patients, as well as an increased role for physician anesthesiologists in the ICU care of infected patients.
A typical anesthesia machine is pictured above. The ventilator aspect of the machine is magnified below:
Anesthesia machine ventilators are capable of delivering variable amounts of oxygen, from room air 21%, to a full 100% oxygen if necessary. Most anesthesia machines are capable of delivering increasing amounts of Positive End Expiratory Pressure (PEEP) up to 20 cmH20, which is often necessary to oxygenate patients with severe ARDS. Anesthesia ventilators can function in volume control mode (by delivering a set volume of a tidal breath), or pressure control mode (by delivering a present inspiratory pressure of each tidal breath).
Anesthesia machines would need to be equipped with an inline bacterial/viral filter on the expiration limb of the disposable breathing hoses, to keep viruses from infecting the machine. This is easily done.
Will anesthesiologists be called to step forward at this time of crisis to man temporary operating rooms that are converted to ICUs? Perhaps. It will depend on the number of critical care MDs who are already available, and whether additional staffing is needed. It will depend on the supply of Personal Protective Equipment (PPE) available. (Asking anyone to step into a COVID-19 ICU without the required PPE is a dangerous request. The ongoing search for more N95 masks, face shields, gowns, and gloves is critical.) It will depend on the ages of the available anesthesia personnel. The death rate for COVID-19 infection increases markedly after age 60, so older anesthetists would be less than ideal. Is there a role for Certified Registered Nurse Anesthetists if ORs are converted into ICUs? Yes.
You can also read an earlier column I wrote on Coronavirus and ICU ventilators.
For more details on anesthesia machines and ventilators, this link will connect you to the website of North American Draeger, a leading manufacturer of anesthesia machines.
Specific information on Draeger anesthesia ventilators can be found here.