Medical and medication devices are real-time systems with safety and timing requirements. They range from hard-real-time, embedded, and reactive systems such as pacemakers to soft-real-time, stand-alone medication dispensers. Many of these devices are already connected to computer networks, especially in hospital intensive-care units, so that patients' conditions detected by sensors can be monitored in real-time at remote computer stations nearby or at other sites. However, remote adjustment of medical devices' output and actuation is typically not allowed due to safety concerns. This article discusses a number of issues such as verification that must be resolved in order to allow cyber-physical operation of medical devices. In particular, we propose using formal methods, self-stabilization, and (m,k)-firm scheduling to allow the safe cyber-physical operation of a medical ventilator, a life-critical reactive device to move breathable air into and out of the lungs of a patient with respiratory difficulties, with the ultimate goal of speeding-up the recovery of the patient.