“Bagging a patient” describes manually providing breaths to a person who is unable to breathe adequately. This procedure uses a portable, hand-held device known as a Bag-Valve Mask (BVM), often called an Ambu bag. The BVM delivers positive pressure ventilation, forcing air into the patient’s lungs to maintain oxygenation and prevent respiratory failure. This manual intervention is used until the patient can breathe independently or a mechanical ventilator is put into place.
The Anatomy and Function of the Bag-Valve Mask
The Bag-Valve Mask is a manual resuscitator comprised of three main components: a self-inflating bag, a one-way valve system, and a face mask. The self-inflating bag acts as the device’s air reservoir and is made of a flexible material that automatically returns to its original shape after being squeezed. This re-expansion draws in either ambient air or, preferably, high-flow oxygen supplied through an attached reservoir.
When a healthcare professional compresses the bag, it forces air through the integrated one-way valve, which directs the gas into the patient’s lungs via the face mask. This valve ensures that the patient’s exhaled breath does not return into the bag, maintaining a clean supply for the next breath. An oxygen reservoir bag is often connected to the BVM to increase the concentration of oxygen delivered to nearly 100%. The system provides immediate, positive pressure ventilation without needing an external power source.
Clinical Situations Requiring Manual Ventilation
Manual ventilation is required whenever a patient’s natural breathing is insufficient to sustain life or has stopped completely, leading to inadequate oxygenation and carbon dioxide removal. One of the most recognized indications is respiratory arrest, or apnea, where the patient has completely ceased breathing. In these situations, the BVM becomes the immediate source of life-sustaining airflow.
The technique is also a standard component of cardiopulmonary resuscitation (CPR) for patients experiencing cardiac arrest. Ventilation is delivered in a specific rhythm, alternating with chest compressions, to ensure oxygen reaches the blood while circulation is artificially maintained. Furthermore, the BVM is used for patients in severe respiratory distress, whose breathing is too slow or shallow to exchange gases effectively, a condition known as hypoventilation.
The BVM is also routinely used for pre-oxygenation immediately before advanced airway management, such as placing a breathing tube (intubation). Delivering high-concentration oxygen via the BVM helps to build up an oxygen reserve in the patient’s lungs. This provides a margin of safety during the brief period when the patient cannot breathe during the intubation attempt.
Performing the Procedure Safely and Effectively
Effective bagging requires proper technique to ensure the air reaches the lungs. The first step is correctly positioning the patient’s head using maneuvers like the head tilt-chin lift or jaw thrust. These actions physically move the tongue and soft tissues away from the airway opening. Maintaining a patent, open airway is crucial for successful ventilation.
A tight seal between the mask and the patient’s face is paramount to prevent air from leaking out. The common “C-E” grip technique involves placing the thumb and index finger in a “C” shape over the mask to press it onto the face, while the remaining three fingers form an “E” shape to lift the jaw into the mask. A two-person technique, where one person focuses solely on maintaining the tight seal with both hands, is often preferred for maximum effectiveness.
Ventilation must be delivered slowly and controlled to avoid complications. For adults, the recommended rate is approximately 10 to 12 breaths per minute, or one breath every five to six seconds. The volume of each breath should be just enough to cause a visible, gentle rise of the chest, often equating to about 500 milliliters for an average adult.
Delivering breaths too quickly or with too much force is a safety concern because it can cause air to enter the stomach instead of the lungs, a complication known as gastric inflation. This occurs when high pressure overcomes the lower esophageal sphincter, allowing air to be forced down the esophagus. Gastric inflation is dangerous because it can lead to vomiting and aspiration of stomach contents into the lungs. It also restricts the movement of the diaphragm, making subsequent ventilation more difficult.