Sponsored by Medtronic
By Tim Nowak for EMS1 BrandFocus
Taking a deep breath, inhaling then exhaling should come naturally, right? But often we take breathing for granted. Not being able to breathe easily is a huge problem for more people than you think. As EMS providers, we often refer to this condition as dyspnea.
So, what’s causing this difficulty? Is your brain telling your lungs to breathe faster or deeper are your lungs filling up with liquid? Your alveoli may not be able to physically dilate and constrict like they normally do. That then, leads to the conclusion that perhaps your patient’s lungs are non-compliant.
Lung compliance – or pulmonary compliance – is a measure of lung expansion. Imagine a balloon affixed to the end of a bag-valve ventilation device. As you squeeze the bag, the balloon expands. Two common factors are driving this expansion: volume and pressure. Issues or complicating factors affecting either of these can affect lung compliance. Decreased muscle function decreased surface area, or even congestion could all be culprits in this equation.
Now, let’s break this down a bit and investigate some of the complications – and fixes – to address lung non-compliance.
Volume vs. pressure ventilation control
Firefighters in the crowd could also relate this to volume versus pressure pump settings. Generally, they measure the amount of water pumped using GPM, or PSI. Similarly, in the ventilator world, volume control essentially involves setting the tidal volume to be delivered, while the pressure is determined afterward.
In a pressure mode, it is just the opposite. Let us say that you want to deliver 30cmH20 pressure to ventilate your patient, the volume delivered will vary with each breath. When using volume control the volume delivered is constant, the pressure varies with each breath. In pressure control, the pressure is constant, and the volume delivered varies each breath. In both examples’ lung compliance is what causes the changes in either volume or pressure.
Understanding acute respiratory distress syndrome
Acute respiratory distress syndrome (ARDS) is a condition where fluid collects in the lungs and is often associated with severely ill patients. Because of this excess fluid, the surface area available for gas exchange to occur is decreased, and supplemental oxygenation or ventilation is often required. It becomes very difficult to inflate the patient’s lungs; many clinicians call this “stiff lungs” or lungs that have low compliance and difficult to keep inflated.
By increasing the positive end-expiratory pressure (PEEP) of the air being delivered, we may be able to “force” some of the water out, thereby increasing the lung compliance making it easy to ventilate the lungs. As long as the balloon can handle this increased pressure and maintain its repeated occurrence, this may be the proper route to take.
Applying positive-end expiratory pressure
When the lungs need a little help to handle the higher repeated pressure being supplied, applying PEEP can aid your patient’s work of breathing.
This is a result of the residual “splinting” that is left as the patient exhales their inhaled volume against a little backpressure. Applying PEEP valves via bag-valve device adapter, or through providing continuous positive airway pressure (CPAP), can accomplish this for your patients. As a result, PEEP – and pressure control – can benefit dyspnea patients suffering from pulmonary edema, emphysema, bronchitis, and other surface area-restricting diseases.
Evaluating a capnograph may be your key to determining different forms of ventilatory problems affecting your patient, along with auscultating their lung sounds (and even adding-in emerging prehospital technologies like ultrasonography).
Poor saturation may be responsible for problems with oxygenation
If there are no suspected obstructions hindering the patient’s oxygenation, then increased pressure may not be the solution. The patient may just need more – or better controlled – volume.
Assuring proper seals with your supraglottic or endotracheal tubes might be your first troubleshooting turn, then adjusting the patient’s volume to verify that what you are delivering is getting “in” to their alveoli.
Hyper-saturation might acutely help in this situation, but that does not necessarily equate to hyperventilation! The key here is making sure that there is an adequate tidal volume being delivered and within the right parameters (accounting for rate, I:E ratios, concentration, etc.).
Ventilation protection
It’s only fitting that we discuss PPE or BSI in the wake of a global pandemic: COVID-19.
What will likely shape into somewhat of our new norm could also be an insight reflecting on what we probably should have been doing all along, which is protecting ourselves while providing ventilation to our patients.
Donning face masks and glasses should have been a 100% compliance item, and now it likely will be (even when the COVID-19 pandemic is over). Adding in-line HEPA filters, spacing tubes, turning on the ambulance’s interior exhaust fan, and even further evaluating which type of ventilatory management our patient needs will all likely be incorporated into our new airway management regiment.
Our focus moving forward will likely be one better emphasized on personal and group protection, along with the need for maintaining a state of compliance, rather than a state of complacency (after all, the lungs need compliance, too!)
Read Next: Troubleshooting common capnography challenges: 3 tips for better results
Get more information from Medtronic
