Figure 1: Sampled locations of the internal breathing-circuit-system (BCS) of anesthesia machine (Primus, Draeger Medical, Germany): A, anesthesia machine „Primus“: encircled the BCS. B, bottom side: (1) inspiratory port, (2) compartment of inspiration, (3) rubber gasket toward CO2 absorber, (4) compartment of expiration, (5) expiratory port. C, centrepiece: (6) rubber gasket of the centrepiece.