A process is provided for controlling a ventilation procedure wherein a liquid ventilation system passes breathing liquid through at least a portion of a patient's pulmonary pathways. In this process, desired ranges for certain process parameters associated with the liquid ventilation system are established. These desired ranges are input into a central processing unit (50). Initial settings for the liquid ventilation system are then made such that the actual conditions which will initially occur during the liquid ventilation procedure fall within their respective desired ranges. Thereafter, the procedure is commenced. During the procedure, conditions are continually monitored by sensors (16, 21, 27). The CPU (50) compares the sensor readings with the desired ranges, and acts to correct any discrepancy. The CPU can trigger alarms (514).