Alarms and their limits in monitoring.

The need to incorporate alarms in monitoring systems is related to the growing complexity of monitoring and the large number of variables. For sophisticated alarms, information about the inputs to the patient is of importance; for example, clinical interventions such as drug administration and ventilation readjustment need to be known to the monitoring system. Alarms are triggered by signals or signal features that exceed thresholds. Each threshold must be seen as a level that needs to be set, either manually or automatically. The large number of levels to be set creates an extra workload for the clinician. Approaches to determine such levels automatically are discussed in this article. Most promising seems the multiple signal approach using an expert system. It seems reasonable to expect that information concerning alarm limits, needed for the operation of knowledge-based alarm systems, may come from integrated departmental data bases.