An ultrasound scanning apparatus, a breathing machine, a medical system and a related method. The ultrasound scanning apparatus comprises an ultrasound scanning unit, an ultrasound controller for controlling the operation of the ultrasound scanning unit, detecting the operation state of the ultrasound scanning unit, generating a first enable signal when detecting that the operation state of the ultrasound scanning unit is transferred from an operating state to a nonoperating state and generating a second enable signal when detecting that the operation state of the ultrasound scanning unit is transferred from the nonoperating state to the operating state, and an enable output end for transmitting the first enable signal or the second enable signal to the breathing machine to control the running of the breathing machine.
