An artificial resuscitation bag comprising: - a deformable bag comprising a gas inlet and a gas outlet, - a gas reservoir comprising an outlet orifice, - a first conduit element fluidly connected to the outlet orifice of the gas reservoir and to the gas inlet of the deformable bag, - a first one-way admission valve arranged in the first conduit element and fluidly communicating with the ambient atmosphere for allowing ambient air to enter into the first conduit element, and - a second one-way valve arranged in the first conduit element between the first one-way admission valve and the gas inlet of the deformable bag for allowing gas to travel only from the first conduit element to the deformable bag, and further comprising: - a first PEP exhaust valve arranged in the first conduit element and fluidly communicating with the ambient atmosphere for venting gas to the atmosphere when the gas pressure, into the first conduit element, exceeds a given threshold, and - a gas conduit arranged in fluid communication with the gas outlet of the deformable bag, - an overpressure valve arranged in the gas conduit, - a third one-way valve arranged in said gas conduit downstream of the overpressure valve, and - a gas delivery conduit in fluid communication with the gas conduct for conveying at least part of the gas circulating into the gas conduct to a patient interface, characterized in that the first PEP exhaust valve comprises a spring and a membrane, said spring applying a constant force on the membrane corresponding to the threshold pressure, the opening pressure of said PEP exhaust valve being of between 1 cmH 2 O and 30 cmH 2 O, and in that the artificial resuscitation bag further comprises: - a pneumatic control valve arranged in the gas conduit downstream of the third one-way valve, and - a derivation conduct having a first end fluidly connected to the gas conduit between the gas outlet of the deformable bag and the overpressure valve, and a second end fluidly connected to the pneumatic control valve, the pneumatic control valve further comprising an inner compartment, the second end of the derivation conduct being fluidly connected to said inner compartment of the pneumatic control valve. - a deformable bag comprising a gas inlet and a gas outlet, - a gas reservoir comprising an outlet orifice, - a first conduit element fluidly connected to the outlet orifice of the gas reservoir and to the gas inlet of the deformable bag, - a first one-way admission valve arranged in the first conduit element and fluidly communicating with the ambient atmosphere for allowing ambient air to enter into the first conduit element, and - a second one-way valve arranged in the first conduit element between the first one-way admission valve and the gas inlet of the deformable bag for allowing gas to travel only from the first conduit element to the deformable bag, - a first PEP exhaust valve arranged in the first conduit element and fluidly communicating with the ambient atmosphere for venting gas to the atmosphere when the gas pressure, into the first conduit element, exceeds a given threshold, and - a gas conduit arranged in fluid communication with the gas outlet of the deformable bag, - an overpressure valve arranged in the gas conduit, - a third one-way valve arranged in said gas conduit downstream of the overpressure valve, and - a gas delivery conduit in fluid communication with the gas conduct for conveying at least part of the gas circulating into the gas conduct to a patient interface, characterized in that the first PEP exhaust valve comprises a spring and a membrane, said spring applying a constant force on the membrane corresponding to the threshold pressure, the opening pressure of said PEP exhaust valve being of between 1 cmH 2 O and 30 cmH 2 O, and in that the artificial resuscitation bag further comprises: - a pneumatic control valve arranged in the gas conduit downstream of the third one-way valve, and - a derivation conduct having a first end fluidly connected to the gas conduit between the gas outlet of the deformable bag and the overpressure valve, and a second end fluidly connected to the pneumatic control valve, the pneumatic control valve further comprising an inner compartment, the second end of the derivation conduct being fluidly connected to said inner compartment of the pneumatic control valve. - a pneumatic control valve arranged in the gas conduit downstream of the third one-way valve, and - a derivation conduct having a first end fluidly connected to the gas conduit between the gas outlet of the deformable bag and the overpressure valve, and a second end fluidly connected to the pneumatic control valve, the pneumatic control valve further comprising an inner compartment, the second end of the derivation conduct being fluidly connected to said inner compartment of the pneumatic control valve.