COVID-19 Resources – Respiratory Basics, Concepts, & Devices
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COVID-19 Resources – Respiratory Basics & Devices Slides
COVID-19 Resources – Respiratory Basics & Devices Notes
COVID-19 has left us with many unanswered questions about the care and treatment for our pandemic population.
In response to the rising questions and concerns, I have decided to create some educational videos that we can refer back to related to the care and treatment of our COVID-19 patients.
Let’s get started on understanding how hemodynamics and arterial blood gas results effect our COVID-19 population.
Let’s discuss oxygenation
Oxygen – we all need it! Sometimes we need more of it to maintain our oxygenation saturations. In these cases, supplemental oxygen is administered via various oxygen delivery devices, ranging from nasal cannulas to invasive ventilation.
There are two important things to consider when delivering supplemental oxygen to our patients:
The oxygen flow rate is the number we dial on the oxygen flow meter, usually between 1-15L/min for low flow devices and 10-60L/min for high flow devices
The FiO2 (fraction of inspired oxygen) is defined as the percentage of concentration of oxygen that a person inhales
Question 1: What is the FiO2 of the air you are breathing right now?
Question 2: What is the FiO2 (percentage of concentrated oxygen) of the oxygen being delivered through the oxygen flow meter on low flow rate devices as soon as you turn it on?
Question 3: Does the oxygen flow rate really change the FiO2 of the pure oxygen that is being delivered through the oxygen flow meter?
You are currently breathing air in and out of your lungs. The air that you are breathing must get from point A (the atmosphere) to point B (your lungs).
If a car was trying to get from point A to point B, it can only do this if you press the accelerator to achieve a certain speed. The faster the speed, the faster you get from point A to point B. The same principles applies to how we breathe. Every time we take a breath in, we are generating what is called the peak inspiratory flow rate.
Difference between Low Flow and High Flow Oxygen Devices
Our normal peak inspiratory flow rate ranges between 20-30L/min. Our respiratory muscles are comfortable and do not tire when we breathe at a normal respiratory rate with this peak inspiratory flow rate.
Let’s say when we are breathing normally, we maintain a peak inspiratory flow rate of 20L/min at room air.
If my patient is receiving 4L/min of oxygen via nasal cannula, is he or she breathing in an FiO2 of 100%?
Patient receives 4L/min from a low flow respiratory device → 16L/min is being diluted by the atmosphere
Low Flow Rate Respiratory Devices
Difference between Low Flow and High Flow Oxygen Devices
Our normal peak inspiratory flow rate ranges between 20-30L/min. Our respiratory muscles are comfortable and do not tire when we breathe at a normal respiratory rate with this peak inspiratory flow rate.
How can we provide more accurate FiO2 to our COVID population?
What is Non-invasive Positive Pressure Ventilation (NIPPV)?
A method to deliver positive-pressure ventilation with or without supplemental oxygen, using a facial or nasal mask with a tight seal.
Indicated for spontaneously breathing patients needing short term ventilatory support.
Mask Styles for NIPPV
Important Considerations for NIPPV
Optiflow/Airvo 2 High Flow Nasal Cannula
The Airvo 2 is a humidifier with integrated flow generator that can deliver high flow, warmed and humidified respiratory gases to spontaneously breathing patients
Let’s discuss oxygenation
Our normal peak inspiratory flow rate ranges between 20-30L/min.
High flow devices help exceed the inspiratory flow rate that the patient generates. The advantages to these systems is it allows healthcare providers to set the FiO2 accurately.
Patient receives 40L/min from a high flow respiratory device (Optiflow/Airvo 2) and has a programmed FiO2 of 50%.
Normal peak inspiratory flow is 20L/min. Every time a patient breaths in they will never exceed the liters programmed on the Airvo 2. This means the patient will receive 50% FiO2 with every breath.
The Most Important Take Points
Let’s Talk About Self-Proning, Incentive Spirometer, and Outcomes
Proning has become a standard in the management of ARDS who have difficulty achieving adequate oxygen saturation. These practices can also be implemented by all patients regardless of respiratory status to help lessen the risk of ARDS/Pneumonia from occurring.
How does it work?
Oxygen from the air goes into the lungs where it meets with blood in tiny vessels. Many tiny vessels or alveolar sacs can collapse when a patient lays supine. Additional insults such as inflammation and fluid build up in ARDS can cause greater discrepancies with oxygenation.
Proning takes weight off the lungs allowing for more alveolar recruitment and better oxygenation.
Benefits from proning can be seen in as little as minutes and many studies have shown a decrease in patient’s being placed on ventilators.
What about incentive spirometer use?
Incentive spirometer allows patients to take deep breaths that expand the lungs and provide better outcomes by