When I went through EMS education, I was taught that when ventilating a patient with a BVM that it was important to deliver as much of the content of the bag as possible. We would almost wring out the bag to get as much as possible. But were we really helping our patient?
Our Patient needed oxygen and if a little was good, a lot must be better. We ventilated hard, pushing the O2 in quickly. But without a secured advanced airway we ran into issue with abdominal distention.
When we bag, we must do so gently. If we push too hard we can push the epiglottis down and force all or part of the air into the stomach. Air in the stomach doesn’t help our patients and only creates a vomit fountain.
I was shown a great aid in teaching how to properly ventilate a patient. Using a BVM, attach an Endotrachial tube to the end immerse the end into a 3/4 full cup of water. If you bag fast the water will bubble out of the cup making a mess, but with practice you can ventilate without spilling the water. This is the proper way to ventilate a patient, gently.
Recent research has shown that Oxygen can destroy surfactant in the lungs. We need this to provide the “lubrication” to keep alveoli open. Think of washing sugar off of you counter-top, the water will always break up the sugar, but we we used a pressure sprayer it would break it up even faster. Fast bagging is the equivalent of a pressure sprayer while ventilating.
We’ve also found that we give far too much oxygen, we bag with 100% oxygen, under positive pressure, how long can we keep our patient’s lung compliance?
The last major faux pas of bagging is doing it too frequently. Our body breathes, in part, to maintain our acid/base balance. We rid ourselves of acid during the expiratory phase. If we bag too frequently, we prevent the body’s natural ability to rid acid. Ventilating once every 6-8 seconds for a non-perfusing patient and once every 5-6 for an a apnic yet perfusing patient would be sufficient.
Positive pressure ventilation can be very beneficial to our patient, but if we do it wrong can have many untoward effects. Slow down, be gentle and help our patients!