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2019 ITU Kaleidoscope Academic Conference

the results are delivered to a person close to the patient or to frequent, as shown in Table 1. The alarm is mainly caused
a remote person in the home IoT platform. by an intentional and temporal removal of the respiration
circuit by a caregiver for suction of sputum or change of the
patient’s body position. An accidental removal may also be
a possible reason. The second most frequent alarm is
peak_press_hi (peak air way pressure is higher than the
setting). This alarm is mainly caused by obstruction of the
air way by sputum or secretion. These alarms are clinically
important to prevent artificial ventilator associated accidents.

Table 1 - Frequency and duration of alarms

Figure 6 - Alarm delivery system configuration

3.2 Alarm analysis

We have implemented an alarm delivery system integrating
an artificial ventilator and pulse oximeter with cooperation
of the family of a pediatric patient with intractable disease 3.3 False alarm reduction
under the study approval at the ethics committee in Kiso
Hospital, Nagano, Japan. The patient was attached to an We found differences in alarm-related functions between
artificial ventilator and pulse oximeter at night. In order to artificial ventilators provided by different manufacturers. To
reduce false alarms, we collected and analyzed alarm data manage medical devices appropriately, we need to
from medical devices for one year from 1 June 2018 to 31 understand alarms of each device behavior, as there looks
May 2019. like there are no standard specifications to handle from
clinical viewpoints [7-8].
The total number of measured days was 327 days in the case
of the artificial ventilator and 269 days for the pulse oximeter. Our alarm delivery system analyzes alarm information, such
The existence of unmeasured days are caused by the patient’s as alarm signals and vital signs data, and provides the
social hospitalization to make caregivers rest and the information and data to the most appropriate caregivers. The
disconnection of cables between medical devices and the escalation service depending on the type of alarms and their
gateway. time duration may be needed to provide better and the most
suitable treatment for a patient.
For each alarm code, we summed up the number of times for
occurrence, frequency in a day and average duration. The The system deals with the following situations: An alarm
alarms on the pulse oximeter accounted for 90% of motion, condition happens, but it lasts a very short time, less than 2
and the frequency exceeded 1200 times per day as shown in seconds. The system should be smart enough not to raise a
Table 1. The alarm means the patient’s body movement and false alarm. The system also takes care of alarm timing. For
clinical emergency is low. We understood that the motion example, when an alarm condition lasts for a short time, the
should be reduced to prevent alarm fatigue of caregivers. system may not raise an alarm immediately; instead it raises
an alarm when the condition lasts beyond a threshold number
Five alarms (pulse_search, sensor_off, loss_of_pulse, of seconds.
loss_of_pulse_with_motion, no_sensor) associate with a
connection between sensors and a patient, and clinical We propose a prototype false-alarm reduction method using
emergency of these alarms are also low in short time. The the duration of pulse oximeter and artificial ventilator alarm
frequency of these alarms is 9.8% in the pulse oximeter. conditions. Alarm priority is determined by the alarm
Three alarms (spo2_lo, pulse_rate_lo, pulse_rate_high) duration, and there are different threshold durations for
associate with vital signs of a patient, and clinical emergency different kinds of alarm. If the alarm duration exceeds an
of these alarms are high. The frequency of these alarms is escalated threshold, the alarm managing state is escalated
0.6% in the pulse oximeter. from alarm-priority Low (L) to alarm-priority Middle (M) or
from M to alarm-priority High (H). The alarm priority and
In ventilator alarms, peak_press_insp_lo (peak air way escalation method are referred to IEC 60601-1-8 [9].
pressure on inspiration is lower than the setting) is the most

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