Evaluation of Emergency Medical Dispatch in Out-Of-Hospital Cardiac Arrest in Taipei Resuscitation (2007) 73, 236—245

1. Evaluation of Emergency Medical
Dispatch in Out-Of-Hospital
Cardiac Arrest in Taipei
Resuscitation (2007) 73, 236—245

2. Introduction
Emergency medical dispatchers are the entry points
to the emergency medical services (EMS).
The implementation of dispatching system has
brought substantial gains in EMS performance with
improved patient outcomes, including increased
survival rate, reduced response time, and increased
efficiency of the EMS system.
By using medically approved and written pre-arrival
instruction (PAI), the dispatcher can instruct the
caller or layperson to start treatment immediately,
especially in the cases of OHCA.

3. Introduction
Telephone-assisted CPR (T-CPR) by dispatcher has
found to be associated with a 50% improvement in
the odds of survival to hospital discharge compared
with those who received no CPR before the arrival of
EMS.
Most people who witness a person in cardiac arrest
may not have been trained in CPR or lack the
knowledge to provide this life-saving intervention
even when facing the victim as a close relative.

4. The instruction to start T-CPR is included in
the protocol of emergency dispatch manual.
When cardiac arrest is suspected, the
dispatcher will ask caller four key questions:
1)What's the patient's skin color?
2)Is there any symptom of airway obstruction?
3)Is there anyone who can perform CPR at the scene?
4)How long has the patient remained comatose?

5. Once OHCA is presumed, the dispatcher will instruct
the caller to perform compression–ventilation CPR
via telephone according to the ERC guidelines and
dispatch an EMS response at the same time.
It is the dispatcher's responsibility to ensure that
they adhere to the instruction protocols, and their
performances are evaluated periodically by their
supervisors.

6. Emotional Content and Cooperation Score (ECCS)
1. Normal conversational speech
2. Anxious but cooperative
3. Moderately upset but cooperative
4. Uncooperative, not listening, yelling
5. Uncontrollable, hysterical

7. Emotional Content and Cooperation Score (ECCS)
 The average ECCS was remarkably low at 1.42 in
Mandarin speaking population.
 Most of the callers’ emotion is manageable and
they were cooperative with the dispatcher
interrogations.
 Female callers were slightly more emotional with a
higher ECCS compared to male callers.

8. Length of The Interview and Time Spent on
Inquiring Address
The median length of the
calls was 32.5 s (interquartile
range: 22.0–58.5) and 90%
of the calls were under
102.4 s.
The median time for
enquiring address was 7.0 s
(interquartile range: 4.0–
10.0) and 90% of the calls
were under 17.2 s.

9. Dispatcher Ability in Identifying Cases of OHCA
Among 193 OHCAs identified by the dispatcher, 189
cases were confirmed by the field provider (false
positive patient, n = 4).
6 patients initially determined as not requiring OHCA
by the dispatcher were later found to be in arrest
(false negative, n = 6).
The sensitivity and positive predictive value (PPV)
for predicting OHCA by dispatchers was 96.9% and
97.9%, respectively.

10. Dispatcher Ability in Identifying Cases of OHCA
Agonal breathing is commonly seen in the initial
phase of OHCA patients. This breathing is an
abnormal, gasping, jerking respiration that produces
movement of the thoracic, neck and mouth,
commonly described by the caller as “occasional or
breathing, barely breathing, weak breathing, heavy,
labored or noisy breathing”.
Failure to recognise agonal respiration could result
in failure to identify OHCA correctly.

11. Determination of The Level of Consciousness and
Breathing Status in The Interview
For OHCA cases, the questions
of “level of consciousness” and
“breathing status” are two of the
most important questions to be
asked to identify possible
OHCA.

12. The Percentage of “Level of Consciousness”
Determined
In 62 cases (31% = 62/199), information on the level
of consciousness was provided directly from the
interview, without it being asked for.
Of the remaining 137 patients, the dispatcher asked
about unconsciousness in 62 cases (45% = 62/137)
and did not ask about it in 75 cases (55% = 75/137).
 Of the 62 cases in which the level if consciousness
was sought, the actual consciousness level was
determined in 57 cases and in 5 cases was unclear.

13. The Percentage of “Breathing Status Determined
In 24 cases (12% = 24/199), the breathing status
was provided directly from the interview, without it
being asked for.
Of the remaining 175 patients, the dispatcher raised
the question of the patients breathing status in 119
cases (68% = 119/175) and did not raise the
question in 56 cases (32% = 56/175).
Of the 119 cases, actual breathing status was
determined in 91 cases and 28 cases it was unclear.

14. Provision of T-CPR
Only 6.5% of patients received bystander CPR prior
to any T-CPR from dispatchers. Approximately 1/3 of
victims received T-CPR provided by the dispatcher
(or duty nurse in dispatching center) and the rest of
the patients received no CPR before arrival of the
paramedics.
T-CPR by dispatcher is associated with a 50%
improvement in the odds of survival to hospital
discharge compared with those who received no
CPR before the arrival of EMS.

15. Provision of T-CPR
When instructions were offered by the dispatcher,
most bystanders agreed to attempt CPR and
actually initiated CPR.
But occasionally bystanders refused to perform CPR
even when they are provided with instructions.
The most common reasons is the fear of contracting
a communicable disease like hepatitis, TB or AIDS
through performing mouth-to-mouth resuscitation.
There is an increasing evidence to suggest that
chest compression only CPR may be as
efficacious as compression–ventilation CPR.

17. Conclusion
Most callers were emotionally stable and cooperative
when calling for help, even when facing cardiac arrest
patients.
The dispatchers have shown satisfactory interview skills
in approaching emergency calls, and the dispatcher's
ability to identify OHCA was high in this study.
The compliance of dispatchers in posing priority
questions such as the level of consciousness and the
breathing status is unsatisfactory. This could possibly be
related to the low rate of T-CPR offered to the callers in
the interviews.