COVID-19 Resources – Respiratory Basics, Concepts, & Devices -

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:

1.The oxygen flow rate and

2.The FiO2

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?

The atmospheric air we inhale contains 21% oxygen and various additional elements

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?

100% oxygen

Question 3: Does the oxygen flow rate really change the FiO2 of the pure oxygen that is being delivered through the oxygen flow meter?

No. The oxygen flow meter is connected to the medical wall supply of oxygen. This oxygen is pure: it is 100% oxygen. Therefore, anything that comes out of the oxygen flow meter has an FiO2 of 100%

•If the oxygen flow rate is set to 1L/min, I will have 1L/min of 100% oxygen

•If the oxygen flow rate is set to 5L/min, I will have 5L/min of 100% oxygen

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%?

•Of course not. The true FiO2 the patient is breathing is based on the flow requirements of the patient (peak inspiratory flow rate).

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

How can we provide more accurate FiO2 to our COVID population?

•The flow rate must exceed the patient’s peak inspiratory flow rate. This is why we use high flow devices such as Optiflow/Airvo 2 and BiPAP.

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

Patients must be able to follow commands and compliant while on NIPPV

•The patient must have the ability to maintain his or her airway

Patients cannot be restrained on NIPPV

•The patient can vomit while on NIPPV and will need the use of his or her hands to remove the mask

Sputum, Eating, and Drinking

•Excessive sputum production can occlude the circuit > Oral fluids are important to make less sputum less viscose and tenacious

•Many patients can tolerate small breaks in NIPPV to allow for eating and drinking. Work with Respiratory Therapy to determine the patient’s ability to maintain oxygenation.

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

•Can configure to 31-37 degree Celsius (heated)

•Can deliver flows from 10 to 60 Liters per minute

•Can deliver oxygen concentrations from 21 to 100%

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

1.It is an increase in FiO2 that increases the oxygen saturations of a patient, not the oxygen flow rate

2.As the peak inspiratory demand changes for a patient, so will the oxygen flow rate demand if we want to maintain a consistent FiO2

3.Hypoxia is not a good thing, but neither is too much FiO2

a.It is important to start weaning oxygen as tolerated on all patients regardless of COVID status. Oxygen toxicity can occur leading to a manifestation of central nervous system and pulmonary toxicity.

4.Effective oxygen therapy is about finding a balance between delivering the lowest FiO2 in order to achieve normal oxygen saturations for the patient

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

1.Keeping alveoli healthy despite chronic lung diseases by maintaining the alveoli open

2.Deep breathing forces the lungs to move more than normal and helps shake excess mucus loose

3.Helps expel bacteria that can be trapped in mucus through respiratory explosion decreasing the risk for lung infections