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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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