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

Is dispatcher-assisted cardiopulmonary resuscitation affected by a bystander's emotional stress state in out-of-hospital cardiac arrest?

AIM

The study aimed to investigate whether a bystander's emotional stress state affects dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) in out-of-hospital cardiac arrest (OHCA). The primary outcome was initiation of chest compressions (Yes/No). Secondarily we analysed time until chest compressions were initiated and assessed how dispatchers instructed CPR.

METHOD

The study was a retrospective, observational study of OHCA emergency calls from the Capital Region of Denmark. Recorded calls were evaluated by five observers using a pre-defined code catalogue regarding the variables wished investigated.

RESULTS

Included were 655 OHCA emergency calls, of which 211 callers were defined as emotionally stressed. When cardiac arrest was recognized, chest compressions were initiated in, respectively, 76.8% of cases with an emotionally stressed caller and 73.9% in cases with a not emotionally stressed caller (2.18 (0.80-7.64)). Cases with an emotionally stressed caller had a longer time until chest compressions were initiated compared to cases with a not emotionally stressed caller, however non-significant (164 s. vs. 146 s.; P = 0.145). The dispatchers were significantly more likely to be encouraging and motivating, and to instruct on speed and depth of chest compressions in cases with an emotionally stressed caller compared to cases with a not emotionally stressed caller (1.64 (1.07-2.56); 1.78 (1.13-2.88)). Barriers to CPR were significantly more often reported in cases with an emotionally stressed caller compared to cases with a not emotionally stressed caller (1.83 (1.32-2.56)).

CONCLUSION

There was no significant difference in initiation of chest compressions or in time until initiation of chest compressions in the two groups. However, the dispatchers were overall more encouraging and motivating, and likely to instruct on speed and depth of chest compressions when the caller was emotionally stressed. Furthermore, barriers to CPR were more often reported in cases with an emotionally stressed caller compared to cases with a not emotionally stressed caller.

TRIAL REGISTRATION

We applied for ethical approval from The Danish National Committee on Health Research Ethics, but formal approval was waived. We received permission for storage of data and to use these for research of OHCAs in the Capital Region of Denmark by Danish Data Protection Agency (P-2021-670) and Danish Health Authorities (R-2,005,114). The study is registered at ClinicalTrials (NTC05113706).

Prehospital triage of patients diagnosed with perforated peptic ulcer or peptic ulcer bleeding: an observational study of patients calling 1-1-2

BACKGROUND

Triage systems are used in emergency medical services to systematically prioritize prehospital resources according to individual patient conditions. Previous studies have shown cases of preventable deaths in emergency medical services even when triage systems are used, indicating a potential undertriage among some conditions. The aim of this study was to investigate the triage level among patients diagnosed with perforated peptic ulcer (PPU) or peptic ulcer bleeding (PUB).

METHODS

In a three-year period in Central Denmark Region, all patients hospitalized within 24 h after a 1-1-2 emergency call and who subsequently received either a PPU or a PUB (hereinafter combined and referred to as PPU/PUB) or a First Hour Quintet (FHQ: respiratory failure, stroke, trauma, cardiac chest pain, and cardiac arrest) diagnosis were investigated. A modified Poisson regression was used to estimate the relative risk of receiving the highest and lowest prehospital response level. Also, a linear regression analysis was used to estimate the relative risk of 30-day mortality.

RESULTS

Of 8658 evaluated patients, 263 were diagnosed with PPU/PUB. After adjusting for relevant confounding variables, patients diagnosed with PPU/PUB were less likely to receive ambulance transportation compared to patients diagnosed with stroke, RR = 1.41 (CI: 1.28-1.56); trauma, RR = 1.28 (CI: 1.15-1.42); cardiac chest pain, RR = 1.47 (CI: 1.33-1.62); and cardiac arrest, RR = 1.44 (CI: 1.31-1.42). Among patients diagnosed with PPU/PUB, 6.5% (CI: 3.3-9.7) did not receive ambulance transportation. The proportion of patients not receiving ambulance transportation was higher among patients diagnosed with PPU/PUB compared to patients diagnosed with an FHQ diagnosis. The 30-day mortality rate among patients diagnosed with PPU/PUB was 7.8% (CI: 4.2-11.1). This was lower than the 30-day mortality rate among patients diagnosed with respiratory failure (P = 0.010), stroke (P = 0.001), and cardiac arrest (P < 0.001), but comparable to the 30-day mortality among patients diagnosed with cardiac chest pain (P = 0.080) and trauma (P = 0.281).

CONCLUSION

Among patients calling 1-1-2, fewer patients diagnosed with PPU/PUB received ambulance transportation than patients diagnosed with FHQ diagnoses, despite a high mortality among patients diagnosed with PPU/PUB.

Impact of an emergency medical dispatch system on survival from out-of-hospital cardiac arrest: a population-based study

Background

In countries where a single public emergency telephone number is not in operation, different emergency telephone numbers corresponding to multiple dispatch centres (police, fire, emergency medical service) may create confusion for the population about the most appropriate service to call. In particular, out-of-hospital cardiac arrest (OHCA) requires a prompt and effective response. We compare two different dispatch systems on OHCA patient survival at 30 days in a national system with multiple emergency telephone numbers.

Methods

We conducted an observational retrospective study of 6871 patients aged 18 years or older with presumed OHCA of cardiac origin between 2005 and 2013 in three counties of the Northern French Alps region. One county had a single dispatch centre combining medical and fire emergencies, and two had multiple dispatch centres. Propensity score matching analyses were performed to compare patient survival at 30 days.

Results

A total of 2257 emergency calls for OHCA were managed by a single dispatch centre and 4614 by a multiple dispatch centre. A single dispatch centre was associated with an increase in survival (adjusted odds ratio [OR] for all patients: 1.7; 95 % confidence interval [CI] = 1.3–2.2; p <0.001; adjusted OR for propensity-matched patients: 2.0; 95 % CI = 1.2–3.4; p = 0.012).

Conclusions

A single dispatch centre was associated with a markedly improved increase of survival among OHCA patients at 30 days in a system with several emergency telephone numbers.

Electronic supplementary material

The online version of this article (doi:10.1186/s13049-016-0247-y) contains supplementary material, which is available to authorized users.

Are regional variations in activity of dispatcher-assisted cardiopulmonary resuscitation associated with out-of-hospital cardiac arrests outcomes? A nation-wide population-based cohort study

AIM

Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) impacts the rates of bystander CPR (BCPR) and survival after out-of-hospital cardiac arrests (OHCAs). This study aimed to elucidate whether regional variations in indexes for BCPR and emergency medical service (EMS) may be associated with OHCA outcomes.

METHODS

We conducted a population-based observational study involving 157,093 bystander-witnessed, resuscitation-attempted OHCAs without physician involvement between 2007 and 2011. For each index of BCPR and EMS, we classified the 47 prefectures into the following three groups: advanced, intermediate, and developing regions. Nominal logit analysis followed by multivariable logistic regression including OHCA backgrounds was employed to examine the association between neurologically favourable 1-month survival, and regional classifications based on BCPR- and EMS-related indexes.

RESULTS

Logit analysis including all regional classifications revealed that the number of BLS training course participants per population or bystander's own performance of BCPR without DA-CPR was not associated with the survival. Multivariable logistic regression including the OHCA backgrounds known to be associated with survival (BCPR provision, arrest aetiology, initial rhythm, patient age, time intervals of witness-to-call and call-to-arrival at patient), the following regional classifications based on DA-CPR but not on EMS were associated with survival: sensitivity of DA-CPR [adjusted odds ratio (95% confidence intervals) for advanced region; those for intermediate region, with developing region as reference, 1.277 (1.131-1.441); 1.162 (1.058-1.277)]; the proportion of bystanders to follow DA-CPR [1.749 (1.554-1.967); 1.280 (1.188-1.380)].

CONCLUSIONS

Good outcomes of bystander-witnessed OHCAs correlate with regions having higher sensitivity of DA-CPR and larger proportion of bystanders to follow DA-CPR.

Challenges in out-of-hospital cardiac arrest - A study combining closed-circuit television (CCTV) and medical emergency calls

The aim of this study was to explore challenges in recognition and initial treatment of out-of-hospital cardiac arrest (OHCA) by using closed-circuit television (CCTV) recordings combined with audio recordings from emergency medical calls.

METHOD

All OHCA captured by CCTV in the Capital Region of Denmark, 15 June 2013-14 June 2014, were included. Using a qualitative approach based on thematic analysis, we focused on the interval from the victim's collapse to the arrival of the ambulance.

RESULTS

Based on the 21 CCTV recordings collected, the main challenges in OHCA seemed to be situation awareness, communication and attitude/approach. Situation awareness among bystanders and the emergency medical dispatchers (dispatcher) differed. CCTV showed that bystanders other than the caller, were often physically closer to the victim and initiated cardiopulmonary resuscitation (CPR). Hence, information from the dispatcher had to pass through the caller to the other bystanders. Many bystanders passed by or left, leaving the resuscitation to only a few. In addition, we observed that the callers did not delegate tasks that could have been performed more effectively by other bystanders, for example, receiving the ambulance or retrieving an Automated External Defibrillator (AED).

CONCLUSION

CCTV combined with audio recordings from emergency calls can provide unique insights into the challenges of recognition and initial treatment of OHCA and can improve understanding of the situation. The main barriers to effective intervention were situation awareness, communication and attitude/approach. Potentially, some of these challenges could be minimized if the dispatcher was able to see the victim and the bystanders at the scene. A team approach, with the dispatcher responsible for the role as team leader of a remote resuscitation team of a caller and bystanders, may potentially improve treatment of OHCA.

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.

A prospective manikin-based observational study of telephone-directed cardiopulmonary resuscitation

INTRODUCTION

Bystander cardiopulmonary resuscitation (CPR) significantly improves the outcome from sudden cardiac arrest (SCA) and is therefore encouraged by offering telephone instructions to the bystander. The effectiveness of this technique was examined in a manikin-based study.

METHODS

Subjects performed CPR on an instrumented adult manikin by following Advanced Medical Priority Dispatch System v11.1 (AMPDS) instructions given by telephone from a different room.

RESULTS

Fifty-one volunteers (26 males, median age 56, range 27-76 years) with no previous experience of CPR were recruited. No volunteers followed the entire instructions correctly. Forty percent were unable to open the airway, only 18% achieved a median inspiration time of 2 s or greater and only 30% delivered tidal volumes within the range 700-1000 ml. Chest compressions were performed at a median rate of 52 min-1 with only 4% of subjects achieving a rate of 100 min-1. Depth of compression was also inadequate in 88% of subjects and hand positioning was incorrect in a third of subjects. The median duty cycle was 46% and there were significant delays between the commencement of the AMPDS protocol and the delivery of the first breath (123 s) and first chest compression (163 s).

DISCUSSION

Few bystanders perform CPR satisfactorily and further work is necessary to improve the effectiveness of telephone CPR instructions.

Improving the first link in the chain of survival: the Antwerp experience

OBJECTIVE

To evaluate the effects of a training programme for emergency medical dispatchers held between 1996 and 1997 in the Belgian city of Antwerp on decision-making regarding tiered emergency medical system responses (mobile intensive care unit teams or basic life support ambulances).

MATERIALS AND METHODS

Two training sessions based on standardized dispatching protocols were given to the dispatchers. To evaluate the effect of this training, 3000 emergency medical system calls were reviewed. Before and after each training session, audio recordings registered in the dispatch centre, hospital records and in-field provider registrations were analysed. The need for advanced life support was retrospectively assessed.

RESULTS

Increased dispatching sensitivity: the proportion of calls in which a mobile intensive care unit team was not dispatched along with the basic life support ambulance, although necessary, dropped from 64% at baseline to 55 and 40%, respectively, after the first and second training sessions. The main effect of the training sessions was a reduction in the amount of errors caused by lack of information. The specificity of the dispatching process, e.g. avoiding sending out mobile intensive care unit teams unnecessarily, was decreased by the first training session but returned to baseline after the second session.

CONCLUSION

Results suggest that only repetitive training efforts can result in increased dispatching sensitivity without decreasing dispatching specificity. We recommend the implementation of medically supervised and standardized dispatching protocols in a continuous education programme.

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.

Equivalence of the standard monophasic waveform shocks delivered by automated external defibrillators?

OBJECTIVE

To study whether two different types of monophasic waveform shocks (i.e. monophasic damped sinusoidal [MDS] and monophasic truncated exponential [MTE] waveform shocks) are of equivalent efficacy.

METHODS

Retrospective review of defibrillation efficacy and outcome in ventricular fibrillation/ventricular tachycardia (VF/VT) patients treated in the same EMS system with AEDs delivering either MDS waveform shocks (n=40) or MTE waveform shocks (n=40).

RESULTS

Defibrillation efficacy of the first shock was 82.5% in the MDS group and 70% in the MTE group (P=0.19). Termination of VF by at least one of the first three shocks was found in 95 and 85% of the patients treated with MDS and MTE waveform shocks, respectively (P=0.22). Restoration of spontaneous circulation occurred in 75% of the MDS group and 30% of the MTE group (P=0.0001). Hospital admission rates were 52.5% in the MDS group and 17.5% in the MTE group (P=0.001). Hospital discharge rates were 17.5% in the MDS group and 7.5% in the MTE group (P=0.18).

CONCLUSIONS

Our data suggest disparity in efficacy between MDS waveform shocks and MTE waveform shocks. Furthermore, our findings should be taken into consideration when the issue of the control group(s) in future clinical trials on new waveforms is discussed.

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.