In a prospective study the present state of alarming by medical devices in an operative intensive care unit of a 1000 bed university hospital was recorded including the responses of the nursing staff. On a multiphase base over 190 h 2041 alarms released by 18 different alarm releasing medicotechnical devices were registrated, indicating an emergency condition in 24 cases (1%), 1345 times (66%) a warning, and in 672 cases a false alarm as judged from the view after. The mean interval between two alarms was 5½ min.
Inadequate adjustment of tolerance limits for alarm activation was found in all groups of medicotechnical devices. Switch on/off keys of alarms might better be replaced by muting buttons, which silence the signal and reactivate it spontaneous after 1 min.
The response of the attendants to the alarm signals was immediate in 94% of all alarms and a delay of more than 2 min in 1% was interpreted as missing. The first response was alarm related in most instances.
We conclude that the number of alarm devices in medicotechnical equipment should be reduced although the present state revealed effective in anticipatory warning in most conditions before the patient's physiologic parameters were concerned.