The purpose of this study was to determine whether auditory warnings in the intensive care unit (ICU) were properly adjusted. An intervention study (before- and-after assessment) was conducted in a 12-bed medical-surgical ICU of an acute-care teaching hospital in Barcelona, Spain. A total of 100 patients with stable haemodynamic and respiratory parameters were included. In the first 3-month phase of the study, minimum and maximum alarm parameters of breathing rate, expired volume/min, airway pressure, SaO(2), arterial blood pressure and heart rate were recorded. In the second 12-month phase of the study, the same alarm parameters were recorded every 4 hours in the patient's medical record. In the third 3-month phase of the study, alarm readings were recorded again as in the first phase. The change throughout coefficient of variation (CV) and the 95% confidence interval (CI) for each alarm were calculated. Following the intervention, there was a statistically significant improvement in alarm readings for expired volume, heart rate and systolic blood pressure, so that alarms had been more properly adjusted to the patient's real value. Nursing staff should be aware that auditory warnings in ICU stable patients are frequently set very far from suitable values. Recording of alarm parameters in the patient's medical record as a routine daily activity was an effective intervention for improving adjustment of auditory warnings.