Multicentric study of monitoring alarms in the adult intensive care unit (ICU): a descriptive analysis

Objectives: To assess the relevance of current monitoring alarms as a warning system in the adult ICU. Design: Prospective, observational study. Settings: Two university hospital, and three general hospital, ICUs. Patients: Hundred thirty-one patients, ventilated at admission, from different shifts (morning, evening, night) combined with different stages of stay, early (0-3 days), intermediate (4-6 days) and late (> 6 days). Interventions: Experienced nurses were asked to record the patient's characteristics and, for each alarm event, the reason, type and consequence. Measurements and main results: The mean age of the patients included was 59.8 +/- 16.4 and SAPS1 was 15.9 +/- 7.4. We recorded 1971 h of care. The shift distribution was 78 mornings, 85 evenings and 83 nights; the stage distribution was 88 early, 78 intermediate and 80 late. There were 3188 alarms, an average of one alarm every 37 min: 23.7 % were due to staff manipulation, 17.5 % to technical problems and 58.8 % to the patients. Alarms originated from ventilators (37.8 %), cardiovascular monitors (32.7 %), pulse oximeters (14.9 %) and capnography (13.5 %). Of the alarms, 25.8 % had a consequence such as sensor repositioning, suction, modification of the therapy (drug or ventilation). Only 5.9 % of the alarms led to a physician's being called. The positive predictive value of an alarm was 27 % and its negative predictive value was 99 %. The sensitivity was 97 % and the specificity 58 %. Conclusions: The study confirms that the level of monitoring in ICUs generates a great number of false-positive alarms.