A patient ventilator system including an alarm, the system comprising: a processor (30) connected with a memory (35), the memory for storing values of ventilator operating parameters and values of alarm thresholds； a display (50) connected to the processor for displaying ventilator operating parameters, patient data and alarm threshold data； and entry means (25) connected to the processor for selecting values of ventilator operating parameters from among a plurality of values of a plurality of ventilator operating parameters, as well as said values of alarm thresholds, wherein the processor enters an alarm condition when values of said patient data exceed said alarm thresholds； wherein in an alarm condition, the display (50) shows an analysis message (606) which gives the root cause of an alarm and which describes any dependent alarm that arises due to said root cause. <；IMAGE>；
