Why EMS Providers Should Monitor Driving Pressures During Ventilation—Not Just Plateau Pressures
When I began my career in EMS, we were often told, “You won’t have to worry about that,” during training. But I quickly learned how misleading that statement was, especially on one of my first calls. I also remember my first ventilator transfer—it was a complete disaster. After that experience, I promised myself I’d never let something like that happen again. Recently, while sipping my coffee, I wondered if I could help prevent situations like that for new providers entering EMS. That’s why I’ve decided to share blog posts about things I’ve learned along the way—lessons that might help other providers during patient care. This particular topic hits close to home, as it’s a hot issue in the critical care and EMS world. For years, we’ve been told to keep plateau pressures under 30, but now new data and studies suggest we can do even better. How exciting is that? By understanding driving pressures and their impact, we can improve patient outcomes. So, without further ado, here’s your first “side hustle” blog post from a paramedic and coffee roaster.
Mechanical ventilation is one of the most critical skills for EMS providers, especially when transporting critically ill patients. However, mastering mechanical ventilation can be daunting for new EMS providers, who are often taught to focus on specific settings like tidal volume, respiratory rate, and plateau pressures. While plateau pressures (keeping them under 30 cmH₂O) have been the gold standard for preventing barotrauma, there’s a growing understanding that this metric alone doesn’t provide the full picture of what’s happening in a patient’s lungs. That’s where driving pressure comes in—a crucial, often overlooked parameter.
In this blog, we’ll explore why EMS providers should not only be mindful of plateau pressures but should also keep an eye on driving pressures to optimize mechanical ventilation and improve patient outcomes.
What is Driving Pressure?
To understand the importance of driving pressure, let’s break it down. Driving pressure is the difference between plateau pressure and PEEP (positive end-expiratory pressure). It reflects the pressure exerted to deliver a tidal volume to the lungs and can give us insight into lung compliance (the ease with which the lungs inflate). Essentially, driving pressure helps us understand how “stiff” or “compliant” the lungs are, which is especially important when managing patients with conditions like ARDS, COPD, or other respiratory pathologies.
The formula is simple:
Driving Pressure = Plateau Pressure - PEEP
If your driving pressure is high, it may indicate that the lungs are less compliant, which could lead to overdistension and lung injury.
Why Not Just Rely on Plateau Pressure?
For years, EMS and ICU protocols have emphasized maintaining plateau pressures below 30 cmH₂O to avoid ventilator-induced lung injury (VILI). While this is a useful rule of thumb, it doesn’t always provide a complete picture. Two patients could have the same plateau pressure, but vastly different driving pressures depending on their lung compliance and the level of PEEP being applied.
Here’s why this matters
- Plateau pressure focuses on total pressure within the alveoli at the end of inspiration.
- Driving pressure focuses on the actual work the lungs are doing to expand with each breath.
- You could have a plateau pressure under 30, but if your driving pressure is still high, you’re at risk for causing lung injury due to overdistension or poor lung recruitment.
The Importance of Monitoring Driving Pressure (yes it does matter)
New EMS providers must understand that ventilator management is not about mastering one or two settings—it’s about understanding the interactions between various parameters and how they impact patient physiology. Focusing solely on plateau pressures could mask underlying problems like poor lung compliance, inadequate alveolar recruitment, or increased risk of VILI.
Here are a few reasons why driving pressures should be monitored:
- Prevents Overdistension: High driving pressures can indicate that the tidal volume being delivered is causing the lungs to stretch beyond their safe limits, even if the plateau pressure looks fine. Monitoring driving pressure ensures that we’re not overinflating the lungs, reducing the risk of barotrauma.
- Reflects Lung Compliance: Driving pressure is an indirect measure of lung compliance. If compliance is low (meaning stiff lungs), you’ll see higher driving pressures. This allows you to tailor your ventilation strategy to the patient’s actual lung condition rather than using one-size-fits-all settings.
- Improves Patient Outcomes: Research shows that keeping driving pressures below 15 cmH₂O is associated with better outcomes in mechanically ventilated patients, particularly in those with acute respiratory distress syndrome (ARDS). For EMS providers, this means monitoring driving pressure can help prevent complications and improve survival during transport.
- Helps Fine-Tune Ventilation: Driving pressure allows EMS providers to adjust PEEP and tidal volumes more precisely. For instance, you may need to increase PEEP to improve oxygenation but be cautious not to increase driving pressure to unsafe levels in the process.
Ventilation is a Balancing Act - don’t just rely on ASV ;)
For new EMS providers, understanding the interplay between settings like tidal volume, respiratory rate, PEEP, plateau pressure, and driving pressure is crucial. Ventilation isn’t just about finding one or two “safe” numbers—it’s about tailoring your approach to the patient’s specific needs and lung mechanics. I won’t go on a rant on why you can’t just put a patient in ASV mode to “set it and forget it” but I will save that for another day.
When managing a ventilated patient, follow these general guidelines:
Tidal Volume: Typically 6-8 mL/kg ideal body weight. (LIS)
Plateau Pressure: Aim to keep this below 30 cmH₂O. I like to live in the 27 neighborhood personally. This obviously can vary from patient to patient.
Driving Pressure: Keep this below 15 cmH₂O if possible, as this minimizes the risk of lung injury.
PEEP: Adjust according to the patient’s oxygenation and compliance, but always keep an eye on how it affects driving pressure. Keep in mind that as you adjust PEEP you gain more “lung” or another way of saying this is recruitment.
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For example, if your patient shows a plateau pressure (Pplat) of 30 and a driving pressure (dP) of 18, adjusting the PEEP (Positive End-Expiratory Pressure) level can reveal a lot about their lung status. Let’s say you increase the PEEP from 7 to 10—this small adjustment can provide valuable insights. If you’re using a solid lung protective strategy, you may find that your patient presents with a lower dP and a Pplat under 30 after this adjustment. Why? Because the increased PEEP improved lung compliance, creating more lung space, which in turn helped reduce the driving pressures without significantly affecting the plateau pressures. On the other hand, if increasing the PEEP leads to higher pressures, it may indicate that the lung is not ready for additional compliance, or you’ve reached the maximum recruitment for that patient. In that case, it may be time to adjust tidal volumes and respiratory rates instead.
As an EMS provider, your goal is to provide safe and effective mechanical ventilation during transport. While plateau pressures are an important metric, don’t rely on them alone. By also monitoring driving pressures, you gain a more comprehensive understanding of your patient’s lung mechanics and can make better-informed adjustments to improve their outcomes.
For new EMS providers, learning mechanical ventilation is a journey. Start by mastering the basics, but always aim to develop a more nuanced understanding of how each setting affects your patient. By doing so, you’ll not only improve your mechanical ventilation skills but also provide the best possible care for your patients. But remember that this all starts with you and your will to improve. If I have learned anything over my years of EMS it’s that “no one is coming” and if you want to be the best for your patients that you need to get after it! Let’s go!!!!
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