Heart attacks (HAs) present clinically with varying symptoms, which are not always described by patients as chest pain (CP) or chest discomfort (CD). Emergency Medical Dispatchers (EMDs) select the CP/CD dispatch protocol for non-chest pain HA symptoms or classic HA complaint of CP/CD. Nevertheless, it is still unknown how often callers report HA symptoms other than CP/CD.

The objective of this study was to characterize the caller’s descriptions of the primary HA symptoms, descriptions of the other HA symptoms, and the use of a case entry (CE) question clarifier.

A retrospective descriptive study analyzed randomly selected EMD audios (where CD/CD protocol was used) from five accredited emergency communication centers in the United States. Several Quality Performance Review (QPR) experts reviewed the audios and recorded callers’ initial problem descriptions, the use of and responses to the CE question clarifier, including the EMD-assigned final determinant code.

A total of 1,261 audios were reviewed. The clarifier was used only 8.5% of the time. The CP/CD symptoms were mentioned alone or with other problems 87.0% of the time. Overall, CP symptom was mentioned alone 70.8%, HA alone 4.0%, and CD symptom alone 1.4% of the time.

9-1-1 callers report potential HA cases using a variety of terms and descriptions—most commonly CP. Other less-common symptoms associated with a HA may be mentioned. Therefore, EMDs must be well-trained to be prepared to probe the caller with a clarifying query to elicit more specific information when “having a heart attack” is the only complaint initially mentioned.

Research in cardiac care has identified significant gender-based differences across many outcomes. Women with heart disease are less likely both to be diagnosed and to receive standard care. Gender-based disparities in the prehospital setting are under-researched, but they were found to exist within rates of 12-lead electrocardiogram (ECG) acquisition within one urban Emergency Medical Services (EMS) agency.

This study evaluates the quality improvement (QI) initiative that was implemented in that agency to raise overall rates of 12-lead ECG acquisition and reduce the gap in acquisition rates between men and women.

This QI project included two interventions: revised indications for 12-lead acquisition, and training that highlighted sex- and gender-based differences relevant to patient care. To evaluate this project, a retrospective database review identified all patient contacts that potentially involved cardiac assessment over 18 months. The primary outcome was the rate of 12-lead acquisition among patients with qualifying complaints. This was assessed by mean rates of acquisition in before and after periods, as well as segmented regression in an interrupted time series. Secondary outcomes included differences in rates of 12-lead acquisition, both overall and in individual complaint categories, each compared between men/women and before/after the interventions.

Among patients with qualifying complaints, the mean rate of 12-lead acquisition in the lead-in period was 22.5% (95% CI, 21.8% - 23.2%) with no discernible trend. The protocol change and training were each associated with a significant absolute level increase in the acquisition rate: 2.09% (95% CI, 0.21% - 4.0%; P = .03) and 3.2% (95% CI, 1.18% - 5.22%; P = .003), respectively. When compared by gender and time period, women received fewer 12-leads than men overall, and more 12-leads were acquired after the interventions than before. There were also significant interactions between gender and period, both overall (2.8%; 95% CI, 1.9% - 3.6%; P < .0001) and in all complaint categories except falls and heart problems.

This QI project resulted in an increase in 12-leads acquired. Pre-existing gaps in rates of acquisition between men and women were reduced but did not disappear. On-going research is examining the reasons behind these differences from the perspective of prehospital providers.

Implementation of high-quality, dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) is critical to improving survival from out-of-hospital cardiac arrest (OHCA). However, despite some studies demonstrating the use of a metronome in a stand-alone setting, no research has yet demonstrated the effectiveness of a metronome tool in improving DA-CPR in the context of a realistic 911 call or using instructions that have been tested in real-world emergency calls.

Use of the metronome tool will increase the proportion of callers able to perform CPR within the target rate without affecting depth.

The prospective, randomized, controlled study involved simulated 911 cardiac arrest calls made by layperson-callers and handled by certified emergency medical dispatchers (EMDs) at four locations in Salt Lake City, Utah USA. Participants were randomized into two groups. In the experimental group, layperson-callers received CPR pre-arrival instructions with metronome assistance. In the control group, layperson-callers received only pre-arrival instructions. The primary outcome measures were correct compression rate (counts per minute [cpm]) and depth (mm).

A total of 148 layperson-callers (57.4% assigned to experimental group) participated in the study. There was a statistically significant association between the number of participants who achieved the target compression rate and experimental study group (P=.003), and the experimental group had a significantly higher median compression rate than the control group (100 cpm and 89 cpm, respectively; P=.013). Overall, there was no significant correlation between compression rate and depth.

An automated software metronome tool is effective in getting layperson-callers to achieve the target compression rate and compression depth in a realistic DA-CPR scenario.

Scott G, Barron T, Gardett I, Broadbent M, Downs H, Devey L, Hinterman EJ, Clawson J, Olola C. Can a software-based metronome tool enhance compression rate in a realistic 911 call scenario without adversely impacting compression depth for dispatcher-assisted CPR? Prehosp Disaster Med. 2018;33(4):399–405

Early recognition of an acute myocardial infarction (AMI) can increase the patient’s likelihood of survival. As the first point of contact for patients accessing medical care through emergency services, emergency medical dispatchers (EMDs) represent the earliest potential identification point for AMIs. The objective of the study was to determine how AMI cases were coded and prioritized at the dispatch point, and also to describe the distribution of these cases by patient age and gender.

No studies currently exist that describe the EMD’s ability to correctly triage AMIs into Advanced Life Support (ALS) response tiers.

The retrospective descriptive study utilized data from three sources: emergency medical dispatch, Emergency Medical Services (EMS), and emergency departments (EDs)/hospitals. The primary outcome measure was the distributions of AMI cases, as categorized by Chief Complaint Protocol, dispatch priority code and level, and patient age and gender. The EMS and ED/hospital data came from the Utah Department of Health (UDoH), Salt Lake City, Utah. Dispatch data came from two emergency communication centers covering the entirety of Salt Lake City and Salt Lake County, Utah.

Overall, 89.9% of all the AMIs (n=606) were coded in one of the three highest dispatch priority levels, all of which call for ALS response (called CHARLIE, DELTA, and ECHO in the studied system). The percentage of AMIs significantly increased for patients aged 35 years and older, and varied significantly by gender, dispatch level, and chief complaint. A total of 85.7% of all deaths occurred among patients aged 55 years and older, and 88.9% of the deaths were handled in the ALS-recommended priority levels.

Acute myocardial infarctions may present as a variety of clinical symptoms, and the study findings demonstrated that more than one-half were identified as having chief complaints of Chest Pain or Breathing Problems at the dispatch point, followed by Sick Person and Unconscious/Fainting. The 35-year age cutoff for assignment to higher priority levels is strongly supported. The Falls and Sick Person Protocols offer opportunities to capture atypical AMI presentations.

ClawsonJJ, GardettI, ScottG, FivazC, BarronT, BroadbentM, OlolaC. Hospital-Confirmed Acute Myocardial Infarction: Prehospital Identification Using the Medical Priority Dispatch System. Prehosp Disaster Med. 2018;33(1):29–35.

Using the Medical Priority Dispatch System (MPDS) – a systematic 911 triage process – to identify a large subset of low-acuity patients for secondary nurse triage in the 911 center is a largely unstudied practice in North America. This study examines the ALPHA-level subset of low-acuity patients in the MPDS to determine the suitability of these patients for secondary triage by evaluating vital signs and necessity of lights-and-siren transport, as determined by attending Emergency Medical Services (EMS) ambulance crews.

The primary objective of this study was to determine the clinical status of MPDS ALPHA-level (low-acuity) patients, as determined by on-scene EMS crews’ patient care records, in two US agencies. A secondary objective was to determine which ALPHA-level codes are suitable candidates for secondary triage by a trained Emergency Communication Nurse (ECN).

In this retrospective study, one full year (2013) of both dispatch data and EMS patient records data, associated with all calls coded at the ALPHA-level (low-acuity) in the dispatch protocol, were collected. The primary outcome measure was the number and percentage of ALPHA-level codes categorized as low-acuity, moderate-acuity, high-acuity, and critical using four common vital signs to assign these categories: systolic blood pressure (SBP), pulse rate (PR), oxygen saturation (SpO2), and Glasgow Coma Score (GCS). Vital sign data were obtained from ambulance crew electronic patient care records (ePCRs). The secondary endpoint was the number and percentage of ALPHA-level codes that received a “hot” (lights-and-siren) transport.

Out of 19,300 cases, 16,763 (86.9%) were included in the final analysis, after excluding cases from health care providers and those with missing data. Of those, 89% of all cases did not have even one vital sign indicator of unstable patient status (high or critical vital sign). Of all cases, only 1.1% were transported lights-and-siren.

With the exception of the low-acuity, ALPHA-level seizure cases, the ALPHA-level patients are suitable to transfer for secondary triage in a best-practices, accredited, emergency medical dispatch center that utilizes the MPDS at very high compliance rates. The secondary nurse triage process should identify the few at-risk patients that exist in the low-acuity calls.

ScottG , ClawsonJ , FivazMC , McQueenJ , GardettMI , SchultzB , YoungquistS , OlolaCHO . Using On-scene EMS Responders’ Assessment and Electronic Patient Care Records to Evaluate the Suitability of EMD-triaged, Low-acuity Calls for Secondary Nurse Triage in 911 Centers. Prehosp Disaster Med. 2016;31(1):46–57.

Shortening response time to an emergency call leads to the success of resuscitation by chest compression and defibrillation. However, response by ambulance or fire truck is not fast enough for resuscitation in Japan. In rural areas, response times can be more than 10 minutes. One possible way to shorten the response time is to establish a system of first responders (eg, police officers or firefighters) who are trained appropriately to perform resuscitation. Another possible way is to use a system of Community First Responders (CFRs) who are trained neighbors. At present, there are no call triage protocols to decide if dispatchers should activate CFRs.

The aim of this study was to determine the predictability to detect if dispatchers should activate CFRs.

Two CFR call triage protocols (CFR protocol Ver.0 and Ver.1) were established. The predictability of CFR protocols was examined by comparing the paramedic field reports. From the results of sensitivity of CFR protocol, the numbers of annual CFR activations were calculated. All data were collected, prospectively, for four months from October 1, 2012 through January 31, 2013.

The ROC-AUC values appear slightly higher in CFR protocol Ver.1 (0.857; 95% CI, 79.8-91.7) than in CFR protocol Ver.0 (0.847; 95% CI, 79.0-90.3). The number of annual CFR activations is higher in CFR protocol Ver.0 (7.47) than in CFR protocol Ver.1 (5.45).

Two call triage protocols have almost the same predictability as the Medical Priority Dispatch System (MPDS). The study indicates that CFR protocol Ver.1 is better than CFR protocol Ver.0 because of the higher predictability and low number of activations. Also, it indicates that CFRs who are not medical professionals can respond to a patient with cardiac arrest.

NarikawaK, SakamotoT, KubotaK, SuzukawaM, YonekawaC, YamashitaK, ToyokuniY, YasudaY, KobayashiA, IijimaK. Predictability of the Call Triage Protocol to Detect if Dispatchers Should Activate Community First Responders. Prehosp Disaster Med. 2014;29(5):1-5.

Diabetes mellitus, although a chronic disease, also can cause acute, sudden symptoms requiring emergency intervention. In these cases, Emergency Medical Dispatchers (EMDs) must identify true diabetic complaints in order to determine the correct care. In 911 systems utilizing the Medical Priority Dispatch System (MPDS), International Academies of Emergency Dispatch-certified EMDs determine a patient's chief complaint by matching the caller's response to an initial pre-scripted question to one of 37 possible chief complaints protocols. The ability of EMDs to identify true diabetic-triggered events reported through 911 has not been studied.

The primary objective of this study was to determine the percentage of EMD-recorded patient cases (using the Diabetic Problems protocol in the MPDS) that were confirmed by either attending paramedics or the hospital as experiencing a diabetic-triggered event.

This was a retrospective study involving six hospitals, one fire department, and one ambulance service in Salt Lake City, Utah USA. Dispatch data for one year recorded under the Diabetic Problems protocol, along with the associated paramedic and hospital outcome data, were reviewed/analyzed. The outcome measures were: the percentage of cases that had diabetic history, percentage of EMD-identified diabetic problems cases that were confirmed by Emergency Medical Services (EMS) and/or hospital records as true diabetic-triggered events, and percentage of EMD-identified diabetic patients who also had other medical conditions. A diabetic-triggered event was defined as one in which the patient's emergency was directly caused by diabetes or its medical management. Descriptive statistics were used for categorical measures and parametric statistical methods assessed the differences between study groups, for continuous measures.

Three-hundred ninety-three patient cases were assigned to the Diabetic Problems Chief Complaint protocol. Of the 367 (93.4%) patients who had a documented history of diabetes, 279 (76%) were determined to have had a diabetic-triggered event. However, only 12 (3.6%) initially assigned to this protocol did not have a confirmed history of diabetes.

Using the MPDS to select the Diabetic Problems Chief Complaint protocol, the EMDs correctly identified a true diabetic-triggered event the majority of the time. However, many patients had other medical conditions, which complicated the initial classification of true diabetic-triggered events. Future studies should examine the associations between the five specific Diabetic Problems Chief Complaint protocol determinant codes (triage priority levels) and severity measures, eg, blood sugar level and Glasgow Coma Score.

ClawsonJ , ScottG , LloydW , PattersonB , BarronT , GardettI , OlolaC . Outcome Accuracy of the Emergency Medical Dispatcher's Initial Selection of a Diabetic Problems Protocol. Prehosp Disaster Med. 2013:28(6):1-6.

In Italy, administration of medications or advanced procedures dictates the prehospital presence of a physician to initiate treatment. Nursing staff is often used as dispatchers in Italian emergency medical ambulance services. There is little data about nursing dispatch performance in detecting high-acuity patients who need prehospital medications and procedures.

To determine the ability of a dispatch center staffed by emergency ambulance nurses to detect prehospital need for physician interventions in the context of a semi-rural area Emergency Medical Services system.

A retrospective analysis of 53,606 calls from the Rovigo Emergency Ambulance Services’ database was undertaken. Physician prehospital interventions were defined as the administration of medications or procedures (advanced airway management and ventilation, pneumothorax decompression, fluid replacement therapy, external defibrillation, cardioversion and pacing). The dispatch codes (assigned by a subjective decision-making process as Red, Yellow, or Green) of all transported prehospital patient calls were matched with an out-of-hospital triage system staffed by clinicians to determine the number of correctly identified prehospital need of physician interventions. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.

The sensitivity of subjective experience-based nursing dispatch in detecting the need for physician interventions was 78.0% (95% CI, 76.9%-79.1%), with a PPV of 36.6% (95% CI, 35.8%-37.5%). Specificity was 83.8% (95% CI: 83.4%-84.1%), with an NPV of 96.9% (95% CI, 96.8%-97.1%).

A dispatch center staffed by nurses with six years of experience and three months of training correctly identified when not to send a doctor to the scene in the absence of need for physician interventions, using a subjective decision-making process. The nurses staffing the dispatch center also worked in the field. Dispatch center staff were not able to predict when there was no need for physician interventions in high-acuity dispatch code patients, resulting in an over-triage and use of emergency physicians on scene.

LeopardiM, SommacampagnaM.Emergency Nursing Staff Dispatch: Sensitivity and Specificity in Detecting Prehospital Need for Physician Interventions During Ambulance Transport in Rovigo Emergency Ambulance Service, Italy. Prehosp Disaster Med. 2013;28(5):1-6.

The Breathing Problems Chief Complaint (CC) protocol in the Medical Priority Dispatch System (MPDS) was the system's most frequently used protocol. While “severe breathing problems” is a significant predictor of cardiac arrest (CA), previous data have demonstrated that the DELTA-level determinant codes in this CC contain patients across a wide spectrum of acuity.

The hypothesis in this study was that certain combinations of caller answers to the breathing problems protocol key questions (KQs) are correlated with different but specific patient acuities.

This was a retrospective study conducted at one International Academies of Emergency Dispatch (IAED) Accredited Center of Excellence. Key Question combinations were generated and analyzed from 11 months of dispatch data, and extracted from MPDS software and the computer assisted dispatch system. Descriptive statistics were used to evaluate measures between study groups.

Forty-two thousand cases were recorded; 52% of patients were female and the median age was 61 years. Overall, based on the original MPDS Protocol (before generating KQ combinations), patients with abnormal breathing and clammy conditions were the youngest. The MPDS DELTA-level constituted the highest percentage of cases (74.0%) and the difficulty speaking between breaths (DSBB) condition was the most prevalent (50.3%). Ineffective breathing and not alert conditions had the highest cardiac arrest quotient (CAQ). Based on the KQ combinations, the CA patients who also had the not alert condition were significantly older than other patients. The percentage of CA outcomes in asthmatic patients was significantly higher in DSBB plus not alert; DSBB plus not alert plus changing color; and DSBB plus not alert plus clammy conditions cases, compared to asthmatic abnormal breathing cases.

The study findings demonstrated that MPDS KQ answer combinations relate to patient acuity. Cardiac arrest patients are significantly less likely to be asthmatic than those without CA, and vice versa. Using a prioritization scheme that accounts for the presence of either single or multiple signs and/or symptom combinations for the Breathing Problems CC protocol would be a more accurate method of assigning DELTA-level cases in the MPDS.

Clawson J, Barron T, Scott G, Siriwardena AN, Patterson B, Olola C. Medical Priority Dispatch System breathing problems protocol key question combinations are associated with patient acuity. Prehosp Disaster Med. 2012;27(4):1-6.

Paramedics accurately estimate the closest trauma hospital for ground transport.

Ground ambulance scene transports of trauma system patients to six participating trauma hospitals in Multnomah County, Oregon from 1 January 1986 to 1 January 1987 were studied. Transports involving multiple patients or pediatric patients were excluded.

A retrospective analysis was performed on consecutive patient transports to be taken to the closest trauma hospital as required by protocol. The availability of each hospital to receive trauma patients was monitored continuously by a central communications facility. Paramedics were provided hospital availability data at the time of patient system entry. When several hospitals were available, the paramedics were required by protocol to select the “closest” hospital. Subsequently, the vector distance from the trauma site to each of the available hospitals was measured using a grid map. This method was validated by odometer measurement (r2 = 0.924). Chisquare analysis was used to analyze hospital bypasses to specific hospitals.

Of the 1193 eligible patients entered into the trauma system, 160 (13%; 95% CI = 11–15%) transports bypassed the closest available hospital for a receiving hospital ≥1 mile more distant. There were 11 (1%; 0–2%) patients transported to a hospital more than five miles more distant. Of the 132 patients with a trauma score (TS) <12, 15 (11%; 6–18%) were taken to a hospital one mile or further beyond the closest hospital. None (0%; 0–2%) were transported more than five miles past the closest hospital. Of the six hospitals, three were bypassed more than one mile significantly more often then they received bypass patients. One hospital received such patients four times more than it was bypassed (p <.001).

While paramedics generally can identify the closest hospital for trauma patient transport, some systematic hospital bypass errors occur. If a community wants assurance of an equitable patient distribution among participating trauma hospitals and assignment of the closest geographic hospital for injured patients, then map vector distance determination to identify the closest available hospital should supplement paramedic dispatching.