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

Abstract

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 ∼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.

Sumàrio

Objectivo: Um dos objectivos deste estudo foi avaliar a capacidade dos Coordenadores de Equipas de Emergência Médica (EMD) em identificarem e priorizarem os casos de Paragem Cardı́aca (PC). Um outro objectivo foi identificar a frequência da respiração agónica nas chamadas por paragem cardı́aca e a descrição da respiração feita por quem faz as chamadas,. Método: Estudo prospectivo avaliando 100 registos das chamadas EMD dos Serviços de Emergência Médica (EMS)-em que foram realizadas medidas de Suporte Avançado de Vida (SAV), de paragem cardı́aca extra-hospitalar. Resultados: A qualidade das entrevistas realizadas pela EMD foi altamente comentada em 63% dos casos, mas insuficiente ou não aprovada nos restantes 37%. O estado de espı́rito de quem fez a chamada não foi problema major para a cooperação. Dos 100 casos, existiu suspeita de que 24 estivessem inconscientes e em paragem respiratória. Outros 38 casos apresentavam-se inconscientes e com dificuldade respiratória. Só em 14 casos foi fornecida informação pela equipa EMD sobre como realizar RCP por quem presenciou a paragem, que foi tentada em 11 e completada em 8. Só quatro dos doentes estavam inconscientes e com respiração anormal. A incidência de suspeita de respiração agónica foi estimada de ∼30% e as descrições foram respiração: difı́cil, pobre, gasping, sibilância, comprometida, ocasional. Conclusão: De entre os casos de suspeita de paragem cardı́aca, os EMDs apenas dão instruções sobre Reanimação Cardio-Pulmonar (CPR) num pequeno número de casos. Um obstáculo major foi a apresentação de respiração agónica. Deve ser fornecida informação-instruções sobre reanimação CPR, em todas as chamadas que identifiquem doentes inconscientes e com respiração agónica. Isto pode melhorar a sobrevivência nas paragens cardı́acas extra-hospitalares.

Resumen

Objetivo: Uno de los objetivos de este estudio fue evaluar la habilidad de los despachadores médicos de emergencia (EMDs) para identificar y priorizar casos de paro cardı́aco (CA), y de ofrecer y conseguir una adecuada reanimación cardiopulmonar (RCP) por testigo asistido por despachador. El otro objetivo fue evaluar la frecuencia de respiración agónica en llamadas de paro cardı́aco y en las descripciones de respiración que hace quien llama. Métodos: Estudio prospectivo evaluando 100 cintas de registro de las llamadas de los EMD a servicios de emergencias médicas (EMS)- casos en que se proporcionó Soporte Vital Avanzado- (ALS), de paro cardı́aco extrahospitalario. Resultados: La calidad de las entrevistas realizadas por los EMD fue altamente recomendable en el 63% de los casos, pero insuficiente o reprobable en el 37% restante. El estado mental del solicitante no fue un problema mayor para la cooperación. En 24 de los 100 casos, se sospechó que estaban inconcientes y en paro respiratorio. Otros 38 casos fueron presentados como inconscientes con respiración anormal. Solo en 14 casos el EMD propuso reanimación por testigo asistida por el despachador, y en 11 de esos se intentó, y fue completada en 8. Sólo 4 de los casos eran pacientes inconcientes con respiración anormal. La incidencia de sospecha de respiración agónica se estimó cercana al 30% y las descripciones fueron: respiración dificultosa, pobre, boqueando, jadeante, alterada u ocasional. Conclusiones: De los casos de sospecha de paro cardı́aco, los EMDs ofrecen instrucciones solo a una pequeña fracción de los solicitantes. La presentación de respiración agónica fue un obstáculo mayor. Deberı́a ofrecerse instrucciones para reanimación asistida por despachador a los pacientes con una combinación de inconciencia y respiración agónica. Esto podrı́a mejorar la sobrevida de el paro cardı́aco extrahospitalario.

Introduction

In cases of out-of-hospital cardiac arrest (CA), the most important assignment for the EMD is to dispatch a defibrillator-equipped pre-hospital response team to the scene of emergency without any untimely delay.

Early defibrillation constitutes one of the most determining factors in the treatment of survival chances among these patients. Within the chain of survival concept, comprising (1) early recognition and access, (2) early CPR, (3) early defibrillation, (4) early advanced care [1], the EMDs assignment can also be considered as a support in the second link of the chain.

As well as interviewing, recognising identifying and prioritising a life-threatening condition, according to these criteria, the EMD can also provide support whilst awaiting ambulance arrival is awaited. By using medically approved, written pre-arrival instructions (PAI), the EMD can instruct a patient or a witness to start treatment immediately, especially in cases of CA and in foreign-body airway obstruction. EMD-assisted CPR by telephone (T-CPR) can support a previously trained rescuer to initiate and improve the quality of bystander CPR. If the bystander lacks CPR experience, the provision of EMD guidance can make all the difference as to whether the victim will receive early help or not [2].

Experimental studies confronting volunteers in an artificial CA scenario have shown that dispatchers can instruct laymen by telephone to perform efficient CPR [3], [4], [5], [6]. In one study when ambulance arrival was later then 4 min, retrospective follow-up studies of patients receiving T-CPR have shown increased survival after arrest [7]. A large study recently published showed the association between T-CPR and survival. This population-based cohort study compared survival among EMS-attended adult CAs (n=7265), by using no bystander-CPR as a reference group. The odds ratio of survival was 1.45 for dispatcher-assisted bystander CPR and 1.69 for bystander CPR without dispatcher assistance, which is an almost 50% improvement in the odds of survival compared with those who received no CPR [8].

The following questions are crucial to determine the possibility of identification of a CA via telephone: (1) What is the problem? (2) Is the patient awake? does he/she respond or react when you shake him/her gently? (3) Is he/she breathing normally?

Culley et al. describes that EMDs omitted the question: “Is the patient breathing normally?” in 21% of cases (n=267). When ‘breathing normally’ was omitted, this often resulted in a delay due to the extra time it took to identify the case as a CA [7]. EMDs must adhere carefully to written protocols, since it has been shown that instructions are performed differently in each case if the protocol is not closely followed [9].

Many patients suffering a CA can continue breathing for several minutes after the arrest; however, the breathing is not normal. Presence of agonal breathing presents a difficulty for the identification of a suspected CA. There are reports showing that identification of CA via telephone fails in 15–25% due to agonal breathing [10], [12]. Clark et al. performed reviews of tape recordings on consecutive, non-traumatic pre-hospital CA cases, treated by the EMS (n=445). Descriptions of agonal activity were noted in 40% of cases; the patient was said to be barely breathing, or having heavy or laboured breathing, noisy, gasping, snorting, gurgling, moaning and groaning breathing.

The survival rate was 27% among those who had had agonal breathing compared with 9% for those without. Agonal breathing was associated with a witnessed collapse, ventricular fibrillation, and discharge alive from hospital [13].

Witnesses of CA are sometimes emotionally distraught. It is possible that they are aware of abnormal breathing, however, they need to see signs of life and, therefore, report the patient as breathing.

The assessment of an emergency call is often based on a layperson's description of the patient's condition and not on an observation conducted by medically trained persons. Laypersons have difficulties describing the situation due to lack of previous experience in a similar predicament.

In the Göteborg dispatch study from 1986, 30% of the cases were judged as feasible for T-CPR, however, this was attempted in only 8% by the EMDs [10].

Clark et al. reported cases of potential or actual CA where they showed that among the true CA cases, 37% were considered suitable or possible for T-CPR, and most were offered assistance [14].

Studies have also shown witness's psychological susceptibility towards interviews, instructions and performance, where 65–90% of the callers are described as being calm in the CA calls. This is probably crucial for co-operation between caller and EMD [7], [15], [16], [17], [18].

The percentages of witnesses's acceptance of an offer of T-CPR is reported to vary between 50 and 59% [2], [15].

The purpose of the present study was to assess the EMDs ability to identify and prioritise a CA case, and the offering and accomplishment of dispatcher-assisted bystander CPR, and to give an account of the frequency of agonal respiration in CA calls and the callers descriptions of breathing.