Identification of cardiac arrest by emergency dispatchers

Emotions in telephone calls to emergency medical services involving out-of-hospital cardiac arrest: A scoping review

Aims

The purpose of this scoping review was to identify and synthesise existing research evidence on emotions in the context of emergency phone calls to emergency medical services (EMS) involving out-of-hospital cardiac arrest (OHCA). The specific objectives were to identify studies that (1) described emotions during emergency OHCA calls; (2) specified an instrument or method for measuring/assessing emotions; and (3) examined the relationship between emotions and call outcomes or patient outcomes.

Methods/Data sources

Five databases were searched on 18 November 2021: Medline, Embase, PsycInfo, CINAHL, and the Cochrane Review Database. Included studies required the following three concepts to be addressed: emotions in the context of EMS calls that involved OHCA. Calls also needed to be made by a ‘second-party’ caller; and each study needed to address at least one of the three specific objectives, as outlined above.

The review was conducted in accordance with the Joanna Briggs Institute guidelines for evidence synthesis for scoping reviews.

Results

Thirteen eligible studies were included for synthesis. All studies met Objective 1; six studies met Objective 2; and seven met Objective 3. One study reported patient fatality due to heightened emotions and ensuing ineffective communications between callers and call-takers.

Conclusion

The review highlights a significant gap in the evidence base of emotions in emergency OHCA-related calls, and the need for a more comprehensive and effective method in assessing and measuring emotions in this context. Relationships between emotions (their expressions and perceptions) and call outcomes (including patient outcomes) also need more rigorous investigation.

Contactless cardiac arrest detection using smart devices

Out-of-hospital cardiac arrest is a leading cause of death worldwide. Rapid diagnosis and initiation of cardiopulmonary resuscitation (CPR) is the cornerstone of therapy for victims of cardiac arrest. Yet a significant fraction of cardiac arrest victims have no chance of survival because they experience an unwitnessed event, often in the privacy of their own homes. An under-appreciated diagnostic element of cardiac arrest is the presence of agonal breathing, an audible biomarker and brainstem reflex that arises in the setting of severe hypoxia. Here, we demonstrate that a support vector machine (SVM) can classify agonal breathing instances in real-time within a bedroom environment. Using real-world labeled 9-1-1 audio of cardiac arrests, we train the SVM to accurately classify agonal breathing instances. We obtain an area under the curve (AUC) of 0.9993 ± 0.0003 and an operating point with an overall sensitivity and specificity of 97.24% (95% CI: 96.86–97.61%) and 99.51% (95% CI: 99.35–99.67%). We achieve a false positive rate between 0 and 0.14% over 82 h (117,985 audio segments) of polysomnographic sleep lab data that includes snoring, hypopnea, central, and obstructive sleep apnea events. We also evaluate our classifier in home sleep environments: the false positive rate was 0–0.22% over 164 h (236,666 audio segments) of sleep data collected across 35 different bedroom environments. We prototype our proof-of-concept contactless system using commodity smart devices (Amazon Echo and Apple iPhone) and demonstrate its effectiveness in identifying cardiac arrest-associated agonal breathing instances played over the air.

Identifying Key Words in 9-1-1 Calls for Stroke: A Mixed Methods Approach

OBJECTIVES

Identifying stroke during a 9-1-1 call is critical to timely prehospital care. However, emergency medical dispatchers (EMDs) recognize stroke in less than half of 9-1-1 calls, potentially due to the words used by callers to communicate stroke signs and symptoms. We hypothesized that callers do not typically use words and phrases considered to be classical descriptors of stroke, such as focal neurologic deficits, but that a mixed-methods approach can identify words and phrases commonly used by 9-1-1 callers to describe acute stroke victims.

METHODS

We performed a mixed-method, retrospective study of 9-1-1 call audio recordings for adult patients with confirmed stroke who were transported by ambulance in a large urban city. Content analysis, a qualitative methodology, and computational linguistics, a quantitative methodology, were used to identify key words and phrases used by 9-1-1 callers to describe acute stroke victims. Because a caller's level of emotional distress contributes to the communication during a 9-1-1 call, the Emotional Content and Cooperation Score was scored by a multidisciplinary team.

RESULTS

A total of 110 9-1-1 calls, received between June and September 2013, were analyzed. EMDs recognized stroke in 48% of calls, and the emotional state of most callers (95%) was calm. In 77% of calls in which EMDs recognized stroke, callers specifically used the word "stroke"; however, the word "stroke" was used in only 38% of calls. Vague, non-specific words and phrases were used to describe stroke victims' symptoms in 55% of calls, and 45% of callers used distractor words and phrases suggestive of non-stroke emergencies. Focal neurologic symptoms were described in 39% of calls. Computational linguistics identified 9 key words that were more commonly used in calls where the EMD identified stroke. These words were concordant with terms identified through qualitative content analysis.

CONCLUSIONS

Most 9-1-1 callers used vague, non-specific, or distractor words and phrases and infrequently provide classic stroke descriptions during 9-1-1 calls for stroke. Both qualitative and quantitative methodologies identified similar key words and phrases associated with accurate EMD stroke recognition. This study suggests that tools incorporating commonly used words and phrases could potentially improve EMD stroke recognition.

Barriers to telephone cardiopulmonary resuscitation in public and residential locations

AIM

Emergency medical telecommunicators can play a key role in improving outcomes from out-of-hospital cardiac arrest (OHCA) by providing instructions for cardiopulmonary resuscitation (CPR) to callers. Telecommunicators, however, frequently encounter barriers that obstruct the Telephone CPR (TCPR) process. The nature and frequency of these barriers in public and residential locations have not been well investigated. The aim of this study is to identify the barriers to TCPR in public and residential locations.

METHODS

We conducted a retrospective study of audio recordings of EMS-confirmed OHCAs from eight regional 9-1-1 dispatch centers between January 2012 and December 2013.

RESULTS

We reviewed 1850 eligible cases (public location OHCAs: N=223 and residential location OHCAs: N=1627). Telecommunicators less frequently encountered barriers such as inability to calm callers in public than in residential locations (2.1% vs 8.5%, p=0.002) or inability to place victims on a hard flat surface (13.9% vs 25.4%, p<0.001). However, the barrier where callers were not with patients was more frequently observed in public than in residential locations (11.8% vs 2.7%, p<0.001).

CONCLUSIONS

This study revealed that barriers to TCPR are distributed differently across public and residential locations. Understanding these differences can aid in the development of strategies to enhance bystander CPR and improve overall patient outcomes.

Telephone-assisted CPR: A literature review

Introduction

Despite numerous efforts, out-of-hospital cardiac arrest (OHCA) survival has not significantly increased in recent decades. The first telephone-assisted cardiopulmonary resuscitation (T-CPR) studies were published in the 1980s, but only in the last decade has T‑CPR been implemented in dispatch centers. T‑CPR is still not available in all dispatch centers and no national or international T‑CPR recommendations are available.

Methods

Studies from PubMed were identified and evaluated. Preliminary information from the European Dispatch Center Survey (EDiCeS) is also included.

Results

In all, 42 studies were included. T‑CPR is implemented in 87.6 % of those dispatch centers which have joined the not-yet published EDiCeS. According to German Resuscitation Registry data, about 10 % of OHCA patients received T‑CPR in 2014. Agonal breathing is the leading cause for nonrecognition of OHCA by the dispatcher. Sensitivity of OHCA recognition by the dispatcher is about 75 %, whereby 8–45 % of these patients were not in cardiac arrest. The time interval from call to first compression is 140–328 s. Instructing rescue breathing by telephone is time consuming, leads to extensive hands-off times, and often to ineffective ventilation; therefore, rescue breathing is not indicated in adults with primary cardiac arrest. Studies showed improved survival with standardized T‑CPR implementation.

Conclusion

T-CPR is established in many dispatch centers. However, emergency call interrogation and T‑CPR vary between dispatch centers and are often performed without evaluation. International recommendations with standardized quality control are necessary and may lead to improved survival.

Emergency dispatch process and patient outcome in bystander-witnessed out-of-hospital cardiac arrest with a shockable rhythm

Objective

To describe the dispatch process for out-of-hospital cardiac arrest (OHCA) in bystander-witnessed patients with initial shockable rhythm, and to evaluate whether recognition of OHCA by the emergency medical dispatcher (EMD) has an effect on the outcome.

Methods

This study was part of the FINNRESUSCI study focusing on the epidemiology and outcome of OHCA in Finland. Witnessed [not by Emergency Medical Service (EMS)] OHCA patients with initial shockable rhythm in the southern and the eastern parts of Finland during a 6-month period from March 1 to August 31 2010, were electronically collected from eight dispatch centres and from paper case reports filled out by EMS crews.

Results

Of the 164 patients, 82.3% (n=135) were correctly recognized by the EMD as cardiac arrests. The majority of all calls (90.7%) were dispatched within 2 min. Patients were more likely to survive and be discharged from the hospital if the EMS response time was within 8 min (P<0.001). Telephone-guided cardiopulmonary resuscitation (T-CPR) was given in 53 cases (32.3%). Overall survival to hospital discharge was 43.4% (n=71). Survival to hospital discharge was 44.4% (n=60) when the EMD recognized OHCA and 37.9% (n=11) when OHCA was not recognized. The difference was not statistically significant (P=0.521).

Conclusion

The rate of recognition of cardiac arrest by EMD was high, but EMD recognition did not affect the outcome. The survival rate was high in both groups. Recognized cardiac arrest patients received bystander CPR more frequently than those for whom OHCA remained unrecognized.

Barriers to recognition of out-of-hospital cardiac arrest during emergency medical calls: a qualitative inductive thematic analysis

Background

The chance of surviving out-of-hospital cardiac arrest (OHCA) depends on early and correct recognition of cardiac arrest by the emergency medical dispatcher during the emergency call. When cardiac arrest is identified, telephone guided cardiopulmonary resuscitation (CPR) and referral to an automated external defibrillator should be initiated. Previous studies have investigated barriers to recognition of OHCA, and found the caller’s description of sign of life, the type of caller, caller’s emotional state, an inadequate dialogue during the emergency call, and patient’s agonal breathing as influential factors. Though many of these factors are included in the algorithms used by medical dispatchers, many OHCA still remain not recognised. Qualitative studies investigating the communication between the caller and dispatcher are very scarce. There is a lack of knowledge about what influences the dispatchers’ recognition of OHCA, focusing on the communication during the emergency call.

The purpose of this study is to identify factors affecting medical dispatchers’ recognition of OHCA during emergency calls in a qualitative analysis of calls.

Methods

An investigator triangulated inductive thematic analysis of recordings of out-of-hospital cardiac arrest emergency calls from December 2012. Participants were the callers (bystanders) and the emergency medical dispatchers. Data were analysed using a hermeneutic approach.

Results

Based on the concept of data saturation, 13 recordings of not recognised cardiac arrest and 8 recordings of recognised cardiac arrests were analysed. Three main themes, six subthemes and an embedded theme emerged from the analysis: caller’s physical distance (caller near patient, caller not near patient), caller’s emotional distance (keeping calm, losing control), caller is a healthcare professional (responsibility is handed over to the caller, caller assumes responsibility), and the embedded theme: caller assesses the patient.

Conclusion

The physical and emotional proximity of the caller (bystander) as well as the caller’s professional background affect the dispatcher’s chances of correct recognition and handling of cardiac arrest. The dispatcher should acknowledge the triple roles of conducting patient assessment, instructing the caller, and reassuring the emotionally affected caller.

Triage By Emergency Medical Dispatchers

Purpose:

This study is an evaluation of the ability of medically trained and controlled emergency medical dispatchers to use telephone triage techniques to direct the appropriate prehospital unit to an emergency scene.

Methods:

Emergency dispatchers, educated in a formal emergency medical dispatch program, were assigned one of four triage priorities to incoming 9-1-1 calls. The actual field management delivered for each patient was compared with the dispatcher's triage to determine the appropriateness of triage.

Results:

A total of 1,045 consecutive calls were reviewed with 74.4% sorted as needing advanced life support (ALS) units on scene; 65.3% (95% CI, 61.9 to 68.6%) of these calls required ALS intervention. A total of 3.4% of the runs sorted to the non-ALS response groups were identified to have required ALS intervention. Comparing the need for ALS intervention, a significant difference was found between the triage groups.

Conclusion:

Emergency medical dispatchers, using a formal system for telephone triage, are able to direct appropriate prehospital resources to the emergency scene.

In out-of-hospital cardiac arrest patients, does the description of any specific symptoms to the emergency medical dispatcher improve the accuracy of the diagnosis of cardiac arrest: a systematic review of the literature

AIM

We sought to determine if, in patients with out-of-hospital cardiac arrest (OHCA), the description of any specific symptoms to the emergency medical dispatcher (EMD) improved the accuracy of the diagnosis of cardiac arrest.

METHODS

For this systematic review, we searched MEDLINE, EMBASE and the Cochrane Library with no restrictions, and hand-searched the gray literature. Eligible studies included dispatcher interaction with callers reporting OHCA, and reported diagnosis of cardiac arrest. Two independent reviewers used standardized forms and procedures to review papers for inclusion, quality, and to extract data from eligible studies. Findings were peer-reviewed by the International Liaison Committee on Resuscitation.

RESULTS

We identified 494 citations; 74 were selected for full evaluation (kappa=0.70) and 23 were included (kappa=0.68), including six before-after, two case-control, and 15 descriptive studies. One before-after study and ten descriptive studies report that inquiring about consciousness and breathing status can help dispatchers recognize cardiac arrest with moderate sensitivity [ranging from 38% to 97%], and high specificity [ranging from 95% to 99%]. One case-control study, three before-after studies, and four observational studies report that abnormal breathing is a significant barrier to cardiac arrest recognition. One before-after study and two descriptive studies report that seizure activity can be a manifestation of cardiac arrest.

CONCLUSION

Dispatchers should recognize cardiac arrest when a victim is described as unconscious and not breathing or not breathing normally, and consider cardiac arrest when generalized seizure is described. They should receive specific instructions on how to best recognize the presence of abnormal breathing.

How Sudden Is Sudden Cardiac Death?

Background— Out-of-hospital sudden cardiac death (SCD) is a frequent cause of death. Survival rates remain low despite increasing efforts in medical care. Better understanding of the circumstances of SCD could be helpful in developing preventive measures and facilitating proper reactions to such a pending event.

Methods and Results— Information on cases of out-of-hospital SCD was collected in the Berlin, Germany, emergency medical system via a questionnaire. Bystander interviews were performed by the emergency physician on scene immediately after declaration of death or return of circulation. Of 5831 rescue missions, 406 involved patients with presumed cardiac arrest. Sixty-six percent had a known cardiac disease. In 72%, the arrest occurred at home, and in 67%, it occurred in the presence of an eyewitness. Information on symptoms immediately preceding the arrest was available in 80% (n=323) of all 406 patients and in 274 of those with witnessed arrest. Symptoms were identical in the 2 groups. Typical angina was present for a median of 120 minutes in 25% of the 274 patients with witnessed arrest and in 33% with a symptom duration of less than 1 hour.

Conclusions— SCD occurs most often at home in the presence of relatives and after a longer period of typical warning symptoms. Although the much-hailed use of public access defibrillation is supported by several studies, the present results raise the question of whether educational measures and targeted educational programs tailored for patients at risk and their relatives should have a higher priority.

Effect of protocol compliance to cardiac arrest identification by emergency medical dispatchers

OBJECTIVES

The objective of the study was to assess the effect of protocol compliance to the accuracy of cardiac arrest (CA) identification by the dispatchers.

METHODS

The study was conducted prospectively over a 1-year period in 1996. The calls categorized as non-traumatic CAs by the dispatcher and calls where the patient was in non-traumatic CA when ambulance crew arrived were included in the study. The data was collected from emergency call tape recordings and ambulance run sheets. The compliance to the protocol was defined as gathering information to two questions: (1) Is the patient awake or can she/he be awakened? and (2) Is she/he breathing normally?

RESULTS

The number of calls included in the study was 776 and the dispatchers identified 83% of the CAs. The protocol was adhered in 52.4% of calls, more often in witnessed than unwitnessed cases (72.3% versus 45.0%, P<0.001). In correctly identified CAs, the protocol compliance was 49.4%. The compliance was higher in cases of unidentified CAs (60.3%, P=0.0326) and in cases of wrongly identified as CAs (false positives, 61.9%, P=0.0276).

CONCLUSIONS

A high identification rate of CAs seems to be achievable despite poor protocol compliance by dispatchers.

Use of automated external defibrillator by first responders in out of hospital cardiac arrest: prospective controlled trial

OBJECTIVE

To test the hypothesis that the use of an automated external defibrillator by police and fire fighters results in higher discharge rates for out of hospital cardiac arrest.

DESIGN

Controlled clinical trial with initial random allocation of automated external defibrillators to first responders in four of the eight participating regions; each region switched from control to experimental, and vice versa, every four months.

SETTING

Amsterdam and surroundings, the Netherlands.

PARTICIPANTS

Patients with witnessed out of hospital cardiac arrests, identified by the emergency medical system between January 2000 and January 2002.

MAIN OUTCOMES MEASURES

Survival to hospital discharge; return of spontaneous circulation; admission to hospital.

RESULTS

243 patients (65% in ventricular fibrillation) were included in the experimental area and 226 patients (67% in ventricular fibrillation) in the control area. The median time interval between collapse and first shock was 668 seconds in the experimental area and 769 seconds in the control area (P < 0.001). 44 (18%) patients in the experimental area versus 33 (15%) patients in the control area were discharged (odds ratio 1.3 (95% confidence interval 0.8 to 2.2), P = 0.33), 139 (57%) experimental versus 108 (48%) control patients had return of spontaneous circulation (1.5 (1.0 to 2.2), P = 0.05), and 103 (42%) experimental versus 74 (33%) control patients were admitted (1.5 (1.1 to 1.6), P = 0.02). The median delay from receipt of call to dispatch of the ambulance was 120 seconds, and the delay to dispatch of the first responder was 180 seconds.

CONCLUSIONS

Use of automated external defibrillators by first responders did not significantly increase survival to discharge from hospital, although it did improve return of spontaneous circulation and admission to hospital. Improved dispatch procedures should increase the success of programmes of first responders using external defibrillators.

Interaction between emergency medical dispatcher and caller in suspected out-of-hospital cardiac arrest calls with focus on agonal breathing. A review of 100 tape recordings of true cardiac arrest cases

AIM

One of the objectives of this study was to assess the emergency medical dispatchers (EMDs) ability for the identification and prioritisation of cardiac arrest (CA) cases, and offering and achievements of dispatcher-assisted bystander cardiopulmonary resuscitation (CPR). The other objective was to give an account of the frequency of agonal respiration in cardiac arrest calls and the caller's descriptions of breathing.

METHODS

Prospective study evaluating 100 tape recordings of the EMD calls of emergency medical service (EMS)-provided advanced life support- (ALS) cases, of out-of-hospital cardiac arrest.

RESULTS

The quality of EMD-performed interviews was highly commended in 63% of cases, but insufficient or unapproved in the remaining 37%. The caller's state of mind was not a major problem for co-operation. Among the 100 cases, 24 were suspected to be unconscious and in respiratory arrest. A further 38 cases were presented as unconscious with abnormal breathing. In only 14 cases dispatcher-assisted bystander CPR was offered by the EMD, and in 11 of these it was attempted, and completed in eight. Only four of the cases were unconscious patients with abnormal breathing. The incidence of suspected agonal breathing was estimated to be approximately 30% and the descriptions were; difficulty, poorly, gasping, wheezing, impaired, occasional breathing.

CONCLUSIONS

Among suspected cardiac arrest cases, EMDs offer CPR instruction to only a small fraction of callers. A major obstacle was the presentation of agonal breathing. Patients with a combination of unconsciousness and agonal breathing should be offered dispatcher-assisted CPR instruction. This might improve survival in out-of hospital cardiac arrest.

Emergency medical dispatch

EMD will always remain somewhat of an imprecise science by nature. 911 is, after all, the access point for lifesaving assistance, and citizens must have absolute freedom to this service. The consequence of having the freedom to request help from any location at any time is that some individuals will use it for the wrong reasons. Present-day dispatchers must serve ever-broadening communities with multiple languages, cultural diversity, and unique health needs. Along with other essential personnel that make up the fabric of the public safety net, emergency medical dispatchers have now become essential to the provision of time-critical skills and compassion for perceived medical emergency.

Dispatcher-assisted telephone CPR: a qualitative study exploring how dispatchers perceive their experiences

OBJECTIVES

To investigate how emergency medical dispatchers (EMDs) perceive their experience of identifying suspected cardiac arrests (CA), and offer and provide instructions in cardiopulmonary resuscitation via telephone (t-CPR).

DESIGN

A qualitative method using the phenomenographic design where 10 EMDs were approached for semi-structured interviews.

MAIN OUTCOME MEASURES

Perception in identifying CA, perception in offering t-CPR and perception in providing t-CPR.

RESULTS

In this analysis, 12 categories and 31 subcategories emerged. The categories for perception in identifying CA were; to trust the witness's account, to be open-minded and to be organised. The categories for perception in offering t-CPR were: to feel prepared to connect with the witness on a mental level by being organised, flexible and supportive, to obtain a basis for assessments and to be observant for diverse obstacles in a situation. Finally, the categories for perception in providing t-CPR were: to feel engaged, to be supportive of the witness, to feel secure by recognising response-feedback from the witness, to observe external conditions with regard to the locality and technical complications, to be composed and adjust to the needs of the situation, to feel competent or to feel despair.

CONCLUSIONS

By listening in an open-minded way, a vast amount of information can be collected. Using criteria-based dispatch (CBD) and their own resources, the possibilities and difficulties of the situation are analysed. The EMDs believe that they are being an empathic support, relieving the witness of the burden of responsibility, and connecting with them mentally to enable them to act at the scene. There are EMDs who feel competent and experienced in managing these cases, and other EMDs who feel insecure and despair. The choice between providing t-CPR and answering incoming calls is prioritised differently among EMDs. There is also a broad subjective assessment among EMDs of offering t-CPR, especially to persons over 70 years old whom they consider incapable of performing CPR. The competence of the EMDs in t-CPR is dependent on re-training and a feedback on patient outcome. Witnesses who are negative towards acting constitute a common problem. There are witnesses with physical impediments or psychologically not susceptible to suggestions. The EMD is also dependent on the knowledge and trustworthiness of the witness. Convincing answers from witnesses prompt a more secure feeling in the EMDs, just as lack of knowledge in the witness has a negative effect on the efforts.

A systematic review of the evidence supporting the use of priority dispatch of emergency ambulances

OBJECTIVES

Systematic reviews of the literature assist in the location, appraisal, and synthesis of available evidence. This systematic review aimed to 1) assess the existing literature evaluating the effect of the priority dispatch of emergency ambulances on clinical outcome and ambulance utilization and 2) assess the relative effectiveness of sources of literature relevant to prehospital care.

METHODS

Systematic review. The quality of each paper was assessed using a standardized seven-point scoring schedule. Sources used were: Medline, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), Bath Information & Data Services (BIDS), bibliographic searching, contacting researchers active in the field, and hand-searching relevant journals. Key words used were: "ambulance," "prioritisation," "dispatch," and "triage."

RESULTS

Three hundred twenty-six papers were identified: 64 (19.6%) were related to the prioritization of emergency ambulances, and only 20 (6.1%) contained original data. The overall quality of publications was poor, seven (35%) papers having a quality score > or = 4. Only half were identified by electronic databases, 55% were identified by people working in the field, and two (10%) were identified by hand-searching (some papers were identified by more than one source). Two high-quality papers support the concept that criteria-based dispatch (CBD) improves clinical outcome; two other papers support CBD's role in improving ambulance utilization.

CONCLUSIONS

There is very little evidence to support the effect of the prioritization of emergency ambulances on patient outcome. Electronic databases identify only approximately half of all relevant prehospital literature. Future systematic reviews in this area should use electronic databases, supplemented by contact with appropriate experts.

The emotional content and cooperation score in emergency medical dispatching

BACKGROUND

A common belief regarding scripted-protocol-driven emergency medical dispatch is that the caller is "too hysterical" or "too uncooperative" to allow a structured interrogation or to receive and act upon dispatch life support instructions.

OBJECTIVES

To examine the emotional content and cooperation scores (ECCSs) of callers in more than 6,000 cases from two communication centers and to investigate the relationships between ECCS and caller party, incident nature, time of day, and geographical location.

METHODS

The ECCS has five levels: 5, uncontrollable, hysterical; 4, uncooperative, not listening, yelling; 3, moderately upset but cooperative; 2; anxious but cooperative; and 1, normal conversational speech. The authors tabulated the ECCS as recorded during case review for a random sample of each center's ongoing quality assurance programs. Statistical tests were used to identify the presence of relationships between ECCS and caller party, arrest/nonarrest situations, time of day, and geographical location.

RESULTS

Regardless of the caller party, the type of call, the time of day, or the geographical location, the mean ECCS of emergency callers is extremely low, indicating that most emergency callers are, in fact, very calm. The average ECCS computed from more than 3,000 cases from British Columbia was 1.05; the average score from almost 3,500 cases from New York State was 1.21.

CONCLUSION

While relationships between ECCS and the different parameters were noted, the differences were so small as to be of little or no use as additional information to assist with complaint triage. The low overall ECCS shows that the typical caller who requests emergency medical assistance is calm enough to be interrogated in a scripted and structured fashion, and is cooperative enough to be responsive to dispatch life support instructions.

Possibilities of implementing dispatcher-assisted cardiopulmonary resuscitation in the community. An evaluation of 99 consecutive out-of-hospital cardiac arrests

AIM

By evaluating tape recordings of true cardiac arrest calls, to judge the dispatchers ability to (a) identify cases as suspected cardiac arrest (CA), (b) give the case the right priority, (c) identify CA cases suitable for dispatcher-assisted, telephone-guided cardiopulmonary resuscitation (T-CPR) and (d) accomplish T-CPR.

METHODS

Evaluation of 99 tape recordings of consecutive cases that had been admitted to the two city hospitals in Göteborg after out-of-hospital CA.

RESULTS

In 70% of the interviews, the dispatcher demonstrated impeccable behaviour with short, distinct questions, quickly resulting in a decision on how to handle the case. In 30%, serious criticism could be voiced as the dispatcher displayed very stressful behaviour, or omitted to ask important questions such as whether the patient was conscious and breathing. In 21%, the interviews indicated a clear opportunity to perform T-CPR. In another 10%, there was a possibility of performing T-CPR. Only in 8% was T-CPR actually accomplished.

CONCLUSIONS

(1) In the majority of the interviews, the quality was very high, while in one-third, serious criticism could be voiced. (2) In our study, only one-third (95% confidence interval, 22-41) of CA cases were suitable for T-CPR, and T-CPR was performed in only 8% of the 99 cases. (3) To optimise the dispatcher ability to identify suspected CA and initiate T-CPR, both medical knowledge and practical training are needed, preferably with protocols for pre-arrival instructions.

Out-of-hospital cardiac arrests in Amsterdam and its surrounding areas: results from the Amsterdam resuscitation study (ARREST) in 'Utstein' style

The purpose of this study was to describe the chain of survival in Amsterdam and its surroundings and to suggest areas for improvement. To ensure accurate data, collection was made by research personnel during the resuscitation, according to the Utstein recommendations. Between June 1, 1995 and August 1, 1997 all consecutive cardiac arrests were registered. Patient characteristics, resuscitation characteristics and time intervals were analyzed in relation to survival. From the 1046 arrests with a cardiac etiology and where resuscitation was attempted, 918 cases were not witnessed by EMS personnel. The analysis focussed on these 918 patients of whom 686 (75%) died during resuscitation, 148 (16%) died during hospital admission and 84 patients (9%) survived to hospital discharge. Patient and resuscitation characteristics associated with survival were: age, VF as initial rhythm, witnessed arrest and bystander CPR. EMS arrival time was significantly shorter for survivors (median 9 min) compared to non-survivors (median 11 min). In 151 cases the police was also alerted and arrived 5 min (median) earlier than EMS personnel. Using the OPC/CPC good functional health was observed in 50% of the survivors and moderate performance in 29%. All links in the chain of survival must be strengthened, but equipping the police with semi-automatic defibrillators may be the most useful intervention to improve survival.

EMT defibrillation does not increase survival from sudden cardiac death in a two-tiered urban-suburban EMS system

OBJECTIVE

The use of automatic external defibrillators (AEDs) by EMS initial responders is widely advocated. Evidence supporting the use of AEDs is based largely on the experience of one metropolitan area, with effect on survival in many systems not yet proved. We conducted this study to determine whether the addition of AEDs to an EMS system with a response time of 4 minutes for first-responder emergency medical technicians (FREMTs) and 10 minutes for paramedics would affect survival from cardiac arrest.

METHODS

This prospective, controlled, crossover study (AED versus no AED) of consecutive cardiac arrests managed by 24 FREMT fire companies took place from 1992 to 1995 in Charlotte, North Carolina, a city of 455,000. Patients were stratified using the Utstein criteria. The primary endpoint was survival to hospital discharge among patients with bystander-witnessed arrests of cardiac origin.

RESULTS

Of the 627 patients, 243 were bystander-witnessed arrests of cardiac origin. Survival to hospital discharge was accomplished in 5 of 110 patients (4.6%; 95% confidence interval [CI] 0.6% to 8.4%) with AED compared with 7 of 133 (5.3%, 95% CI 1.5% to 9.1%) without AED (P = .8). Both groups were comparable with regard to age, gender, history of myocardial infarction, congestive heart failure or diabetes, arrest at home, bystander CPR, and whether or not ventricular fibrillation (VF) was the initial rhythm. For arrests of any cause, witnessed by bystanders or EMS personnel, with an initial rhythm of VF or ventricular tachycardia (VT), 5 of 77 (6.5%, 95% CI 1.0% to 12.0%) with AED survived compared with 8 of 105 patients (7.6%, 95% CI 2.5% to 12.7%) without AED (P = .8). Statistically significant differences were noted in race and EMS response times between the two groups, which did not affect survival.

CONCLUSION

Addition of AEDs to this EMS system did not improve survival from sudden cardiac death. The data do not support routinely equipping initial responders with AEDs as an isolated enhancement, and raise further doubt about such expenditures in similar EMS systems without first optimizing bystander CPR and EMS dispatching.

Do victims of an out-of-hospital cardiac arrest benefit from a training program for emergency medical dispatchers?

In this paper, we assessed the effects of a training course for emergency medical dispatchers on the handling of out-of-hospital cardiac arrest cases in the dispatch center of a two-tiered emergency medical services system. A total of 112 cardiac arrest cases were studied; 64 before and 48 after the training course. Before the course, all relevant information was obtained in 36% of cases, only partial information in 56% and no useful medical information in 8%. The corresponding figures after the training program were 62, 38 and 0%, respectively (2 x 3 chi2 test, P = 0.01). Trends towards an increase in the percentage of cases in which a second-tier team was sent immediately after the initial call (58 vs 75%; chi2 test, P = 0.06) and towards shorter overall intervals between receipt of the call and dispatch of the second-tier team (logrank test, P = 0.10) were noticed. Similarly, the survival rate increased from 2% before, to 8% after the training course (chi2 test with Yates' correction, P = 0.24). We conclude that our training program for emergency medical dispatchers produced some beneficial effects.

Analysing calls by lay persons reporting cardiac arrest

Prior to establishing a protocol for pre-arrival instructions for cardio-pulmonary resuscitation in the Vienna emergency medical system dispatch centre, a study was performed to determine whether any problems exist which may compromise guidance for basic life-support on the telephone. To evaluate the feasibility of prearrival instructions, a retrospective analysis of cardiac arrest calls was performed. We reviewed the Vienna emergency medical services dispatch centre tape recordings, ambulance run sheets and the hospital charts of 114 patients suffering from atraumatic cardiac arrest. Analysis showed that in 59 cases the arrest occurred in the victim's home. The telephone and the patient were either in the same or in adjoining rooms in 55% of the calls. We did not experience any technical or language difficulties. The caller and victim were related in 51 cases. The callers were completely calm in 77% and fairly calm in an additional 15%. Not one caller was distraught. Our data show that most objections to the feasibility of pre-arrival instructions can be refuted. We conclude that in Vienna the setting and location of arrest will impose few problems on the performance of bystander-cardio-pulmonary resuscitation using pre-arrival instructions given by dispatchers.

Increasing the efficiency of emergency medical services by using criteria based dispatch

STUDY OBJECTIVES

To determine whether criteria based dispatch (CBD) improved the efficiency of the emergency medical services system.

DESIGN

A before and after design was used to measure effects of CBD. Data were reviewed from medical reports from January 1986 through June 1992.

SETTING

King County, Washington, excluding the city of Seattle.

PARTICIPANTS

Residents who called 911 to report a medical emergency.

INTERVENTIONS

Emergency medical dispatching (EMD), basic life support (BLS), and advanced life support (ALS).

RESULTS

Findings show a decrease in ALS responses for two tracer conditions that medical control physicians determined not require ALS intervention. The percentage of febrile seizures in which paramedics responded decreased from 41% to 21% (P < .001). The percentage of cerebrovascular accidents in which paramedics responded decreased from 41% to 28% (P < .001). CBD led to a decrease, from 4.7% to 3.8% (P < .001), in frequency of requests by BLS units for dispatch of ALS units. There was no increase in the time required to dispatch each call.

CONCLUSION

CBD increased the efficiency of the EMS system by significantly reducing ALS responses to incidents not requiring ALS intervention and reducing requests by BLS units for dispatch of ALS units while maintaining a consistent time from receipt of call to dispatch.

Telephone triage of cardiac emergency calls by dispatchers: a prospective study of 1386 emergency calls

OBJECTIVES

To evaluate the handling of potential cardiac emergency calls by dispatchers, to determine their final diagnosis and urgency, and to determine the value of the main complaint in predicting urgency and the ability of the dispatchers to recognise non-urgent conditions.

DESIGN

Prospective data collection and recording of main complaint of emergency calls placed via the 06-11 alarm telephone number with follow up to hospital when the patients were transported and the general practitioner when they were not.

SETTING

Dispatch centres of the emergency medical services in Amsterdam (urban area) and Enschede (rural area).

PATIENTS

1386 consecutive adult subjects of emergency calls placed by citizens about chest problems or unconsciousness not caused by injury.

MAIN OUTCOME MEASURES

Frequency of characteristics of the calls, outcome in diagnosis, and assessment of urgency.

RESULTS

69 (5%) patients were dead when the ambulance arrived. Diagnosis was established in 1071 patients (77%). The disorders most often reported were cardiac, with acute ischaemia in 15% of all subjects. In 28% of cases and for each presenting complaint no organic explanation was found. Overall 39% of all emergency calls were urgent; the urgency rate was lowest for calls for people with abdominal discomfort. Dispatchers correctly identified 90% of the non-urgent calls, but 55% of the calls that they identified as urgent proved to be non-urgent.

CONCLUSION

Currently, direct dialling for an ambulance without the intervention of a general practitioner imposes a high work load on emergency systems and hospitals because triage by dispatchers is not sufficiently accurate. It may be possible to increase the accuracy of triage by developing and testing decision algorithms.

Incidence of agonal respirations in sudden cardiac arrest

STUDY OBJECTIVE

To discover the frequency of agonal respirations in cardiac arrest calls, the ways callers describe them, and discharge rates associated with agonal respirations.

DESIGN

We reviewed taped recordings of calls reporting cardiac arrests and emergency medical technician and paramedic incident reports for 1991. Arrests after arrival of emergency medical services were excluded.

SETTING

King County, Washington, excluding the city of Seattle.

PARTICIPANTS

Four hundred forty-five persons with out-of-hospital cardiac arrests receiving emergency medical services.

INTERVENTIONS

Telephone CPR, emergency medical technicians-defibrillation, and advanced life support by paramedics.

MEASUREMENTS AND MAIN RESULTS

Any attempts at breathing described by callers were identified, as well as whether agonal respirations could be heard by dispatcher, emergency medical technicians, or paramedics. Agonal respirations occurred in 40% of 445 out-of-hospital cardiac arrests. Callers described agonal breathing in a variety of ways. Agonal respirations were present in 46% of arrests caused by cardiac etiology compared with 32% in other etiologies (P < .01). Fifty-five percent of witnessed arrests had agonal activity compared with 16% of unwitnessed arrests (P < .001). Agonal respirations occurred in 56% of arrests with a rhythm of ventricular fibrillation compared with 34% of cases with a nonventricular fibrillation rhythm (P < .001). Twenty-seven percent of patients with agonal respirations were discharged alive compared with 9% without them (P < .001).

CONCLUSION

There is a high incidence of agonal activity associated with out-of-hospital cardiac arrest. Presence of agonal respirations is associated with increased survival. These findings have implications for public CPR training programs and emergency dispatcher telephone CPR programs.

Dispatcher-assisted telephone CPR: common delays and time standards for delivery

STUDY OBJECTIVES

To determine the rate of bystander CPR before and after implementation of a telephone CPR program in King County; to determine the reasons for dispatcher delays in identifying patients in cardiac arrest in delivering CPR instructions over the telephone; and to suggest time standards for delivery of the telephone CPR message.

DESIGN

An ongoing cardiac arrest surveillance system to calculate the annual bystander CPR rates from 1976 through 1988. Two hundred sixty-seven taped recordings of calls reporting cardiac arrests to nine emergency dispatch centers during 1988 were reviewed and timed.

SETTING

King County, Washington, excluding the city of Seattle.

PARTICIPANTS

Two hundred sixty-seven persons with out-of-hospital cardiac arrests receiving emergency medical services. Arrests in doctors' offices, clinics, or nursing homes were excluded.

INTERVENTIONS

Dispatcher-assisted telephone CPR.

MEASUREMENTS AND MAIN RESULTS

The rate of bystander CPR increased from 32% (1976 through 1981) to 54% (1982 through 1988) after implementation of the dispatcher-assisted telephone CPR program, although an increase in survival could not be demonstrated. The median time for dispatchers to identify the problem was 75 seconds; to deliver the early protocols, 19 seconds; to deliver the ventilation instructions, 25 seconds; and to deliver compression instructions, 30 seconds. The total time to deliver the entire CPR message was 2.3 minutes. The most frequent cause for delay was unnecessary questions (57%) with questions about patient age asked most frequently (32%). Other causes included the caller not being near the patient (29%) and deviations from protocol (22%).

CONCLUSION

In a metropolitan emergency medical services system, a dispatcher-assisted telephone CPR program was associated with an increase in bystander CPR. Delays in proper delivery of telephone CPR can be minimized through training.

Prehospital resuscitation in Helsinki, Finland

Helsinki, a city of 500,000 inhabitants, is served by a two-tiered emergency medical system with basic emergency medical technicians in ordinary ambulances and one physician-staffed prehospital emergency care unit. All 266 patients with prehospital cardiopulmonary resuscitation during 1987 were studied. Two hundred twelve patients with presumed heart disease and a witnessed arrest were analyzed further. Their response times for basic life support and advanced life support were 5.5 and 10.7 minutes, respectively. The initial cardiac rhythm in 144 patients (68%) was ventricular fibrillation. In 79 of these patients, cardiopulmonary resuscitation was successful, and 39 patients (27%) were discharged from hospital. The patients who survived had shorter response times for basic life support and their arrest locations was more often outside home, compared with the nonsurvivors. The results seem comparable with emergency medical systems in the United States, but a need to reduce response times is identified.