Therapy devices, for example, anesthesia devices for anesthetizing a patient, are used in practice, as a rule, in conjunction with at least one monitoring device for monitoring therapy parameters such as respiration parameters, anesthesia parameters and/or vital parameters of the patient being anesthetized.
These monitoring devices may be directly integrated within the particular therapy devices but also provided as independent, external monitoring device, and they trigger an alarm or an alarm report upon the onset of certain circumstances. The monitoring device may be designed as so-called monitors.
When such a monitoring device is used, it is common practice to preset respective limit values for the parameters to be monitored, above or below which an alarm report is triggered. These limit values, which are also called alarm limits, are usually set by the attending physician or his team, quite generally by the operator of the therapy device.
When such a monitoring device according to the state of the art are used, errors occur in alarm triggering, which may be directly or indirectly disadvantageous for the therapy being monitored or for the health and/or the well-being of the patient being treated. Such an error in alarm triggering is given, for example, when no alarm is triggered in case of an actually occurring error that should have led to an alarm (false negative alarm). This may be due to alarm limits that are set too generously or deactivated alarm limits. However, alarm reports are also sent regularly in case of anesthesia or therapy taking place properly without the development of a situation in which an alarm should have been triggered (false positive alarm, also called false alarm). This may be due to alarm limits set too strictly.
The appearance of a false negative alarm implies the great risk that the physician, who relies upon an alarm in the case of malfunction of the therapy device (for example, the anesthesia device) or in case of deviation of a parameter from its target range, detects the actually occurring error only late at best due to the absence of this alarm.
False positive alarm reports or false alarms are, by contrast, not directly hazardous to the health of the patient, but they may be indirectly hazardous. Thus, false alarms would be suitable for diverting the physician from his actual work or for preventing him from performing his work. False alarms could also be hazardous because their repeated occurrence could give reason to the physician or his team not to pay generally the necessary attention to future alarms, to generally ignore future alarms or to even deactivate the alarm means of the monitoring device in order to avoid future alarms altogether.
Such a deactivation by the physician, often intended as a temporary measure only, could regularly also occur in order to do away with a large number of false alarms, which are due in anesthesia devices, for example, to the curve usual for some forms of anesthesia, such as the slow build-up of a gaseous anesthetic during the induction of anesthesia up to a target concentration. There is later a risk in this case that one will forget to manually reactivate the alarm means. If a case of error that does require an alarm occurs in such a case, no alarm will be triggered because of the deactivation (false negative alarm), which may be associated with a safety risk for the patient. Lowering the alarm limits to a generous alarm setting to avoid false alarms will in turn increase the risk of false negative alarms, i.e., the absence of justified and necessary alarm reports.