📚 AMBU Bag Mechanics
Key Points
Structure: body, inlet and outlet valves.
Compression delivers gas; release refills with ambient or oxygen.
Valves control flow: inlet opens on release, outlet on compression.
🛠️ Components of the AMBU Bag
Definition: The AMBU bag (manual resuscitator) is a self‑expanding ventilation device
consisting of a body, an inlet valve assembly, and an outlet valve assembly.
Body
Made of a material that re‑expands automatically after
compression.
Allows use of atmospheric air for ventilation when no supplemental
oxygen is available.
Inlet Valve Assembly
Closes when the bag is compressed.
Opens when the bag is released, permitting ambient air to fill the
bag for the next breath.
Outlet Valve Assembly
Contains a one‑way “fish‑mouth” valve (primary) and an optional
exhalation one‑way valve.
🌬️ Ventilation Mechanics
1. Compression Phase
The operator squeezes the bag → air (or oxygen‑enriched mixture)
is forced out through the outlet valve to the patient.
2. Release Phase
Bag re‑expands → inlet valve opens, drawing atmospheric air (or
oxygen‑rich gas) into the reservoir.
The expansion volume depends on how far the bag was squeezed.
Key Points
Structure: body, inlet and outlet valves.
Compression delivers gas; release refills with ambient or oxygen.
Valves control flow: inlet opens on release, outlet on compression.
🛠️ Components of the AMBU Bag
Definition: The AMBU bag (manual resuscitator) is a self‑expanding ventilation device
consisting of a body, an inlet valve assembly, and an outlet valve assembly.
Body
Made of a material that re‑expands automatically after
compression.
Allows use of atmospheric air for ventilation when no supplemental
oxygen is available.
Inlet Valve Assembly
Closes when the bag is compressed.
Opens when the bag is released, permitting ambient air to fill the
bag for the next breath.
Outlet Valve Assembly
Contains a one‑way “fish‑mouth” valve (primary) and an optional
exhalation one‑way valve.
🌬️ Ventilation Mechanics
1. Compression Phase
The operator squeezes the bag → air (or oxygen‑enriched mixture)
is forced out through the outlet valve to the patient.
2. Release Phase
Bag re‑expands → inlet valve opens, drawing atmospheric air (or
oxygen‑rich gas) into the reservoir.
The expansion volume depends on how far the bag was squeezed.
