Ambu bag or we usually call bag valve mask is a manual device that can assist breathing which required human intervention in every breath cycle, patient in critical conditions or in ICU are less likely to support or coordinate/respond to such devices, Ambu bag is more helpful in case of trauma patients, In chronic conditions, or where long-duration support or in case of therapy Ambu bag support is not a very frequent choice by healthcare providers. There is another name for them is manual resuscitator. Whereas a ventilator can take control over the human breathing cycle completely without extensive human intervention(except initial setup) It can control inhalation and exhalation cycle of breathing in a very precise manner even if the patient is totally noncooperative/unconscious state. The ventilator can also control the oxygen and air percentage as well, ventilators have a more data-driven controlled approach.
To summarize Ambu is a manual device for short support in emergency circumstances, whereas ventilators are fully automatic control for longer support with very little human intervention.
In COVID-19 situation ventilators are more suitable and perfect device as compare to Ambu bags .
Yet Ambu bag have its convenience.
Bag valve mask/manual resuscitator manufactured by Xiamen Winner Medical is widely appreciated by the end user of more over 50 countries.