Comparison of Emergency Medical Dispatch Systems for Performance of Telecommunicator-Assisted Cardiopulmonary Resuscitation Among 9-1-1 Callers With Limited English Proficiency

This cohort study evaluates the prevalence of telecommunicator-assisted cardiopulmonary resuscitation among 9-1-1 callers with limited English language skills using 2 emergency medical services dispatch systems.


Introduction
Early provision of cardiopulmonary resuscitation (CPR) is a key factor in survival from out-of-hospital cardiac arrest (OHCA). [1][2][3] Although the benefit of bystander CPR has been well established, previous literature indicates that less than 30% of patients in Los Angeles (California) who experienced cardiac arrest received bystander CPR, 4 including only 13% of cases involving African American or Latino patients. 5 Telecommunicator-assisted CPR (T-CPR), in which 9-1-1 call takers quickly identify cases of possible cardiac arrest and provide CPR instructions, has been associated with a substantially increased rate of bystander CPR 6,7 and improved survival. [8][9][10] The Los Angeles Fire Department (LAFD), the second largest municipal 9-1-1 emergency medical services (EMS) agency in the United States, used the Medical Priority Dispatch System (MPDS) for more than 25 years . In late 2014, the LAFD developed a new series of scripted questions that decreased the number of questions needed to identify individuals experiencing a potential cardiac arrest and lowered the threshold for providing T-CPR. This new program, called the Los Angeles Tiered Dispatch System (LA-TDS), went into use on December 1, 2014. Since then, LA-TDS has substantially decreased call processing times for time-critical 9-1-1 emergencies, 11 decreased undertriage in cases of field-confirmed OHCA, 12 and improved the global rates of T-CPR. 13 The objective of this cohort study was to ascertain whether implementation of LA-TDS was associated with increased prevalence of T-CPR among 9-1-1 callers with limited English proficiency in the City of Los Angeles. The predefined secondary hypothesis before LA-TDS implementation was that there would be no difference in the prevalence of T-CPR between MPDS and LA-TDS cohorts.

Methods
This cohort study was a predefined secondary analysis of a before-and-after intervention study 14 that compared telecommunicator management of OHCA at the City of Los Angeles 9-1-1 Dispatch Center during 2 separate 3-month periods: (1) between January 1 and March 31, 2014, using MPDS and (2) between January 1 and March 31, 2015, using LA-TDS. The present retrospective study was approved by the institutional review board of the University of Southern California, which granted a waiver of informed consent because the research involved no more than minimal risk to participants, the research could not be carried out practicably without the waiver, and the waiver would not adversely affect the rights and welfare of the participants. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline. 15 The LAFD is the sole 9-1-1 EMS system for the entire City of Los Angeles. As an all-life hazard emergency response agency, the LAFD provides tiered basic and/or advanced life support response using a combination of ambulances and nontransporting fire engine or fire truck resources and performs all of its own transports to the hospital.
The LAFD 9-1-1 Dispatch Center is a secondary public safety answering point that receives approximately 1.1 million calls annually, resulting in more than 400 000 EMS incidents per year according to internal LAFD data. The dispatch center is staffed by sworn firefighters who have a minimum of basic life support training and 2 years of field EMS experience. Callers interact with a single telecommunicator (ie, a 9-1-1 call taker who is otherwise known as a dispatcher) who uses LA-TDS scripted and semiscripted questions to arrive at a dispatch code, which is then entered into a homegrown Los Angeles computer-assisted dispatch system. Each dispatch code is assigned an algorithm of resource assignments on the basis of location, level of service, and need for additional personnel on scene. Telecommunicators work 24-hour platoon duty shifts and field approximately 100 calls per shift. No change to the dispatch center, computer-assisted dispatch system, dispatch or ambulance staffing, dispatch or field time-stamping procedures, or electronic health record was observed during the study periods. Further information on telecommunicator training and accreditation has been previously published. 11,12,14 Cases were selected by retrospectively reviewing LAFD electronic health records of patients who were diagnosed in the field with cardiac arrest, and filtering was based on Utstein elements 16 as well as study inclusion and exclusion criteria. In this study, we included all LAFD-attended cardiac arrests with attempted resuscitation. Incidents were excluded if they were of obvious traumatic cause, occurred in a medical clinic or nursing home, were handled by non-LAFD dispatch centers, were witnessed by EMS personnel, or if CPR was in progress before the 9-1-1 call.
For all incidents that met the inclusion criteria, personnel who were blinded to the study hypothesis located the recorded 9-1-1 call for that incident. Data were provided to a non-LAFD biostatistician (C.L.) from the Southern California Clinical and Translational Science Institute who assigned a unique nonsequential case number to each audio recording. Four trained non-LAFD abstractors listened to all recorded calls and used strict criteria to ascertain whether T-CPR was initiated and to identify the elapsed time from the start of the call until key events in the call (eg, delivery of CPR instructions, delivery of first chest compression). Twenty calls from each comparison group were screened by all abstractors to assess interrater reliability for study elements (κ = 0.76). The primary outcome of this study was the prevalence of T-CPR among 9-1-1 callers with limited English proficiency for field-confirmed nontraumatic cardiac arrests. This prevalence was defined as the number of patients who received telecommunicator-assisted chest compressions during a 9-1-1 call with callers with limited English proficiency divided by the total number of callers with limited English proficiency who met the inclusion criteria and did not meet 1 or more of the exclusion criteria.
A caller was considered to have limited English proficiency if, in the best judgment of the 9-1-1 audio recording reviewer, the person did not speak English as a primary language and thus had limited ability to speak and understand English. 17 Outcome definitions, abstractor approach to minimizing potential bias, data handling, and statistical methods have been described elsewhere. 14 Race and ethnicity of patients were classified by the EMS personnel on scene.

Statistical Analysis
Univariate characteristics of patients, electronic records of calls, and call review outcomes were described using mean (95% CI) for continuous outcomes and No. (%) for categorical outcomes. Time outcomes were examined for normality and nonparametric statistics and were investigated for any serious deviations from normality. Comparisons between LA-TDS and MPDS were made using t tests (for normally distributed continuous outcomes), Kruskal-Wallis test (for non-normally distributed continuous outcomes), or χ 2 tests (for categorical outcomes). Timed events were compared using nonparametric tests that examined the median, the range, and the distribution of times. For the primary outcome of prevalence of telecommunicator-assisted chest compressions, α = .05. Ad hoc examination was performed using logistic regression to ascertain whether language proficiency moderated the improvements in T-CPR between MPDS and LA-TDS.
Analyses were performed with IBM SPSS Statistics for Macintosh, version 24.0 (IBM Corp). Data were analyzed between January and December 2017.

Results
For the study periods of January 1 to March 31, 2014 (MPDS cohort), and January 1 to March 31, 2015 (LA-TDS cohort), a total of 1027 EMS-treated cardiac arrest cases occurred, of which 13 audio recordings could not be recovered and 417 cases were excluded per study protocol (Figure). A

JAMA Network Open | Emergency Medicine
Performance of Telecommunicator-Assisted CPR Among 9-1- broken down by language proficiency and dispatch system cohorts are shown in Table 1.
No overall differences in age, sex, or known comorbidities between excluded and included patients or between callers in MPDS and LA-TDS cohorts were observed. No significant differences were found between callers in MPDS and LA-TDS cohorts except that callers with limited English proficiency in LA-TDS cohort had a higher prevalence of heart disease. Furthermore, no significant differences between MPDS and LA-TDS cohorts were found in use of the language line for real-time As seen in

Discussion
In this cohort study, the implementation of LA-TDS was associated with a significant and disproportionate increase in T-CPR prevalence involving callers with limited English proficiency. This improvement was achieved using the same 9-1-1 dispatch personnel, minimal retraining, and only a 1-month run-in period (December 2014).
We hypothesized that the disproportionate increase in T-CPR using LA-TDS may be explained by the simplification of the initial portion of the caller interview. This simplification includes decreasing the number of questions, not asking questions that have already been answered, treating vague    This finding is consistent with a previous study that suggested language lines can promote delays in interaction. 20 We hypothesize that such delays may have implications for caller-telecommunicator tempo and rapport, caller reassurance, caller confidence, and bystander recruitment to perform more advanced response, such as chest compressions.
A key observation was that callers with limited English proficiency were notably underrepresented in OHCA incidents using both MPDS and LA-TDS. limited English proficiency to examine rates of OHCA reporting, assess attitudes and beliefs about using 9-1-1, and identify barriers to confidently accessing emergency care in these populations.
If T-CPR is as successful as shown in this study in communities with limited English proficiency, additional efforts should be made to integrate targeted teaching on bystander recognition of potential cases of OHCA, early uninterrupted bystander CPR, confident use of 9-1-1, and folowing T-CPR to improve outcomes in culturally marginalized communities. The precise elements of LA-TDS that are associated with increased T-CPR performance in distinct communities also warrant further investigation.

Limitations
This study has several limitations. First, it took place in a single city with a fire department-based EMS system that is staffed with sworn telecommunicators with training and field experience as emergency medical technicians or paramedics; thus, the setting may not be representative of other 9-1-1 response agencies. Second, Los Angeles has a high percentage of non-English-speaking residents, which may not be representative of other communities. Third, the potential of a Hawthorne effect exists given the political nature and scrutiny of this transition in dispatch systems. 22 Fourth, the caller party was not an exclusion or assessed in this study, and given the small number of callers with limited English proficiency, it is conceivable that a shift in the distribution of