Exhaling During Manual Ventilation Is As Important As Inhaling

Exhalation during manual ventilation is as important as inhalation. One of my readers recently asked a very important question about ventilating a patient with a bag-valve-mask device: “Is there an outlet for the expired air of the patient?” The answer is yes. When ventilating a patient we are concentrating, and rightfully so, on watching the lungs expand and verifying that we hear breath sounds. It is just as important to verify that your patient can exhale. All ventilation devices have a built in pressure relief valve, also called a pop-off valve, which allows you to balance the force needed to expand the lungs with the ability to the patient to passively exhale. Failure to allow exhalation can lead to patient injury from barotrauma.

Illustration showing the parts of a bag-valve-mask device, using a self-filling bag as an example.

Common parts for bag-valve-mask devices, In this case a self-inflating style bag. The reservoir bag, when present, allows near 100% inspired oxygen if allowed to fill.

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Difference in Manual Ventilation: Self-Inflating Ventilation Bag vs. a Free Flow Inflating Bag

Manual ventilation with a bag-valve-mask device requires a good mask seal against the face in order to generate the pressure to inflate the lungs. But it also requires knowledge of how to effectively use the ventilation device to deliver a breath. This article will discuss the differences in ventilation technique for self-inflating vs free-flow ventilation bags. Understanding those differences is important for successful manual ventilation of your patient. Continue reading

Assisting Ventilation With Bag-Valve-Mask

As an anesthesiologist, I often run to emergencies where the patient is not breathing adequately and requires intubation. However, before any intubation, a patient in respiratory distress/failure needs ventilation. Providers who have passed ACLS are often able to ventilate an apneic patient well because they have practiced on the manikin. However, I often see that providers have more difficulty trying to assist ventilation of a patient who is still breathing spontaneously.

The typical inexperienced provider will try to provide large, slow breaths just as they were taught in ACLS. Unfortunately these breaths are often out of synch with the patient’s own breathing. Squeezing the bag while the patient is exhaling means that your inflation pressure must not only overcome the diaphragm, but also reverse the passive outflow of air, the elastic recoil of the lungs, and the rebound of the chest wall combined. The vocal cords may be closed. Ventilating out of synch with the patient won’t be as effective. The breath you deliver will take the path of least resistance to enter the stomach or escape from the mask. It often makes the patient cough.

Even worse,  providers will occasionally hesitate to try to assist a patient’s breathing while waiting for the intubation team because they feel they don’t know how. Delay in improving ventilation can place your patient at higher risk of complication. This is unfortunate because in many ways assisting ventilation is even easier than manually ventilating an apneic patient. Let’s see why. Continue reading