Understanding the 'Ambu-Bag' and associated valves

**Caution (Medical Info from frontline specialist discussions)**

The Ambu-Bag (and similar compression ventilators) are designed for <10 hours of operation and encounter several common issues:
-the valves get sticky with condensed liquid
-dangerous levels of CO2 accumulate
-reuseable Ambu-Bag systems are not common, meaning the ones available are less sturdy.

When there are a lack of ventilators (like in the COVID-19 crisis), the built-in, tank-fed oxygen systems are routed into the bag, making it difficult to track the balance of gasses over time.

Professionals are sitting bedside, tending to the manual ventilator setups.

PEEP - Positive End Expiratory Pressure Fio2 - Fraction of Expired Oxygen - Fso2 - From O2 tank or wall fixture - Supplimental oxygen Fdo2 - Fraction of Delivered oxygen - How much got to the patient 

3 Valves at the back end
-One way check valve (Disk type) Ensuring the one way flow of breathing support gasses
-One way check valve (Disk type) allowing Room air to enter in the event of heavy negative pressure
-One way check valve (Disk type) preventing too much flow into the patient or too much positive pressure