Which emergency medical dispatch codes predict high prehospital nontransport rates in an urban community?

ICD-10 Classification in the Practice of Emergency Medical Teams: New Insights

The role of the emergency medical system is to provide assistance to every person in a state in the event of a sudden threat to health and life. Emergency medical teams (EMTs) are an important element of this system, making diagnoses based on the International Classification of Diseases (ICD-10). The study was aimed at analysing the causes of EMT intervention based on groups of diagnoses codified according to the ICD-10. The analysis was based on data from 116,278 EMT interventions in central-eastern Poland in 2017-2019. The research showed that EMT most often made diagnoses based on groups of ICD-10 codes: R00-R99-Symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified (39.11%); S00-T98-Injury, poisoning, and certain other consequences of external causes (18.23%); and I00-I99-Diseases of the circulatory system (15.57%). The analysis of the obtained results showed statistically significant differences (p < 0.0001) regarding the area of intervention (urban, rural), sex, age of the patient, and the method of completion of the activities by EMTs in relation to the group of ICD-10 diagnoses for the diagnosis. The conducted study showed the actual reasons for EMT calls. The use of the ICD-10 classification has practical application in EMTs, as it enables the identification of a disease or health problem.

Dispatch Categories as Indicators of Out-of-Hospital Time Critical Interventions and Associated Emergency Department Outcomes

OBJECTIVES

Emergency medical services (EMS) systems increasingly grapple with rising call volumes and workforce shortages, forcing systems to decide which responses may be delayed. Limited research has linked dispatch codes, on-scene findings, and emergency department (ED) outcomes. This study evaluated the association between dispatch categorizations and time-critical EMS responses defined by prehospital interventions and ED outcomes. Secondarily, we proposed a framework for identifying dispatch categorizations that are safe or unsafe to hold in queue.

METHODS

This retrospective, multi-center analysis encompassed all 9-1-1 responses from 8 accredited EMS systems between 1/1/2021 and 06/30/2023, utilizing the Medical Priority Dispatch System (MPDS). Independent variables included MPDS Protocol numbers and Determinant levels. EMS treatments and ED diagnoses/dispositions were categorized as time-critical using a multi-round consensus survey. The primary outcome was the proportion of EMS responses categorized as time-critical. A non-parametric test for trend was used to assess the proportion of time-critical responses Determinant levels. Based on group consensus, Protocol/Determinant level combinations with at least 120 responses (∼1 per week) were further categorized as safe to hold in queue (<1% time-critical intervention by EMS and <5% time-critical ED outcome) or unsafe to hold in queue (>10% time-critical intervention by EMS or >10% time-critical ED outcome).

RESULTS

Of 1,715,612 EMS incidents, 6% (109,250) involved a time-critical EMS intervention. Among EMS transports with linked outcome data (543,883), 12% had time-critical ED outcomes. The proportion of time-critical EMS interventions increased with Determinant level (OMEGA: 1%, ECHO: 38%, p-trend < 0.01) as did time-critical ED outcomes (OMEGA: 3%, ECHO: 31%, p-trend < 0.01). Of 162 unique Protocols/Determinants with at least 120 uses, 30 met criteria for safe to hold in queue, accounting for 8% (142,067) of incidents. Meanwhile, 72 Protocols/Determinants met criteria for unsafe to hold, accounting for 52% (883,683) of incidents. Seven of 32 ALPHA level Protocols and 3/17 OMEGA level Protocols met the proposed criteria for unsafe to hold in queue.

CONCLUSIONS

In general, Determinant levels aligned with time-critical responses; however, a notable minority of lower acuity Determinant level Protocols met criteria for unsafe to hold. This suggests a more nuanced approach to dispatch prioritization, considering both Protocol and Determinant level factors.

Association between initial presenting level of consciousness and patient acuity - A potential application for secondary triage in emergency ambulance calls

INTRODUCTION

Conscious state assessment is important for the triage of emergency patients. In this study, we measured the association between ambulance patients' conscious state and high versus lower acuity, with a view to informing telephone triage assessment of conscious state.

METHODS

Data were analysed from one year of emergency ambulance incidents in Perth, Western Australia. Patient conscious state at the time of paramedic arrival was compared to acuity (based on paramedic assessment and management). We determined the proportion of high-acuity patients across six levels of consciousness (Alert, Confused, Drowsy, Voice Response, Pain Response, Unresponsive) overall, and within individual protocols of the Medical Priority Dispatch System (MPDS).

RESULTS

The proportion of high acuity patients increased with each step across the consciousness scale. Applying conscious state as a binary predictor of acuity, the largest increases occurred moving the threshold from Alert to Confused (22.0-48.6% high acuity) and Drowsy to Voice Response (61.9-89.5% high acuity). The Area Under the Curve (AUC) of the Receiver Operating Characteristic was 0.65. Within individual protocols, the highest AUC was in Cardiac Arrest (0.89), Overdose/Poisoning (0.81), Unknown Problem (0.76), Diabetic Problem, (0.74) and Convulsions/Fitting (0.73); and lowest in Heart problems (0.55), Abdominal Pain (0.55), Breathing Problems (0.55), Back Pain (0.53), and Chest Pain (0.52).

CONCLUSION

Based on these proportions of high acuity patients, it is reasonable to consider patients with any altered conscious state a high priority. The value of conscious state assessment for predicting acuity varies markedly between MPDS protocols. These findings could help inform secondary triage of ambulance patients during the emergency call.

Improving ambulance dispatch triage to trauma: A scoping review using the framework of development and evaluation of clinical prediction rules

OBJECTIVE

Ambulance dispatch algorithms should function as clinical prediction rules, identifying high acuity patients for advanced life support, and low acuity patients for non-urgent transport. Systematic reviews of dispatch algorithms are rare and focus on study types specific to the final phases of rule development, such as impact studies, and may miss the complete value-added evidence chain. We sought to summarise the literature for studies seeking to improve dispatch in trauma by performing a scoping review according to standard frameworks for developing and evaluating clinical prediction rules.

METHODS

We performed a scoping review searching MEDLINE, EMBASE, CINAHL, the CENTRAL trials registry, and grey literature from January 2005 to October 2021. We included all study types investigating dispatch triage to injured patients in the English language. We reported the clinical prediction rule phase (derivation, validation, impact analysis, or user acceptance) and the performance and outcomes measured for high and low acuity trauma patients.

RESULTS

Of 2067 papers screened, we identified 12 low and 30 high acuity studies. Derivation studies were most common (52%) and rule-based computer-aided dispatch was the most frequently investigated (23 studies). Impact studies rarely reported a prior validation phase, and few validation studies had their impact investigated. Common outcome measures in each phase were infrequent (0 to 27%), making a comparison between protocols difficult. A series of papers for low acuity patients and another for pediatric trauma followed clinical prediction rule development. Some low acuity Medical Priority Dispatch System codes are associated with the infrequent requirement for advanced life support and clinician review of computer-aided dispatch may enhance dispatch triage accuracy in studies of helicopter emergency medical services.

CONCLUSIONS

Few derivation and validation studies were followed by an impact study, indicating important gaps in the value-added evidence chain. While impact studies suggest clinician oversight may enhance dispatch, the opportunity exists to standardize outcomes, identify trauma-specific low acuity codes, and develop intelligent dispatch systems.

Which health-related reasons lead to prehospital emergency care and how does subjective emergency status connect to subsequent care?

Objectives/Background

In many countries, the use of emergency medical services (EMS) increases steadily each year. At the same time, the percentage of life-threatening complaints decreases. To redesign the system, an assessment and consideration of the patients’ perspectives is helpful.

Methods

We conducted a paper-based survey of German EMS patients who had at least one case of prehospital emergency care in 2016. Four health insurance companies sent out the questionnaire to 1312 insured persons. We linked the self-reported data of 254 respondents to corresponding claims data provided by their health insurance companies. The analysis focuses a.) how strongly patients tend to call EMS for themselves and others given different health-related scenarios, b.) self-perceived health complaints in their own index case of prehospital emergency care and c.) subjective emergency status in combination with so-called “objective” characteristics of subsequent EMS and inpatient care. We report principal diagnoses of (1) respondents, (2) 57,240 EMS users who are not part of the survey and (3) all 20,063,689 inpatients in German hospitals. Diagnoses for group 1 and 2 only cover the inpatient stay that started on the day of the last EMS use in 2016.

Results

According to the survey, the threshold to call an ambulance is lower for someone else than for oneself. In 89% of all cases during their own EMS use, a third party called the ambulance. The most common, self-reported complaints were pain (38%), problems with heart and circulation (32%), and loss of consciousness (17%). The majority of respondents indicated that their EMS use was due to an emergency (89%). We could detect no or only weak associations between patients’ subjective urgency and different items for objective care.

Conclusion

Dispatchers can possibly optimize or reduce the disposition of EMS staff and vehicles if they spoke directly to the patients more often. Nonetheless, there is need for further research on how strongly the patients’ perceived urgency may affect the disposition, rapidness of the service and transport targets.

Analysis of the Interventions of Medical Emergency Teams in Older Patients in Selected Polish Cities with County Status: A Retrospective Cohort Study

Introduction: Geriatric patients account for a large proportion of interventions of medical emergency teams (METs). The aim of this study was to analyse medical emergency interventions in the Biała Podlaska and Chełm (Poland) between 2016 and 2018 in a group of patients ≥ 65 years of age. Materials and Methods: We analysed medical records of 1200 older patients treated by METs in Biała Podlaska and Chełm (Lublin Province, Poland). The research was conducted from June 2019 to March 2020 at the Emergency Medical Service Station in Biała Podlaska and the Medical Rescue Station in Chełm (Independent Public Complex of Health Care Facilities). Results: A total of 92.5% of medical emergency service interventions took place at the patient’s home. The mean time of stay at the scene was 20 min. The highest number of interventions occurred between 8:00 p.m. and 8:59 p.m. There were no statistically significant differences in the type of ambulance used depending on the patient’s sex, while there was a statistically significant relationship between priority code and sex. Cardiovascular diseases were diagnosed in 40% of patients, and the symptoms were not precisely classified in almost the same percentage of patients. Mortality cases accounted for 3.1% of the 1200 interventions analysed. Ambulance dispatch resulted in the patient being transported to the hospital emergency department in 69.1% of cases. Conclusions: METs were called for a variety of diseases due to the fact that geriatric patients are not able to distinguish a life-threatening condition. Medical procedures performed by METs from Biała Podlaska and Chełm were closely related to the initial diagnoses made by these teams. It was irrelevant whether a specialist or non-specialist medical emergency service was used. Paramedics are very well trained to practice their profession and are able to provide treatment to older patients in a state of sudden life threat.

Ambulance dispatch of older patients following primary and secondary telephone triage in metropolitan Melbourne, Australia: a retrospective cohort study

BACKGROUND

Most calls to ambulance result in emergency ambulance dispatch (direct dispatch) following primary telephone triage. Ambulance Victoria uses clinician-led secondary telephone triage for patients identified as low-acuity during primary triage to refer them to alternative care pathways; however, some are returned for ambulance dispatch (secondary dispatch). Older adult patients are frequent users of ambulance services; however, little is known about the appropriateness of subsequent secondary dispatches.

OBJECTIVES

To examine the appropriateness of secondary dispatch through a comparison of the characteristics and ambulance outcomes of older patients dispatched an emergency ambulance via direct or secondary dispatch.

DESIGN

A retrospective cohort study of ambulance patient data between September 2009 and June 2012 was conducted.

SETTING

The secondary telephone triage service operated in metropolitan Melbourne, Victoria, Australia during the study period.

PARTICIPANTS

There were 90 086 patients included aged 65 years and over who had an emergency ambulance dispatch via direct or secondary dispatch with one of the five most common secondary dispatch paramedic diagnoses.

MAIN OUTCOME MEASURES

Descriptive analyses compared characteristics, treatment and transportation rates between direct and secondary dispatch patients.

RESULTS

The dispatch groups were similar in demographics, vital signs and hospital transportation rates. However, secondary dispatch patients were half as likely to be treated by paramedics (OR 0.51; CI 0.48 to 0.55; p<0.001). Increasing age was associated with decreasing treatment (p<0.005) and increasing transportation rates (p<0.005).

CONCLUSION

Secondary triage could identify patients who would ultimately be transported to an emergency department. However, the lower paramedic treatment rates suggest many secondary dispatch patients may have been suitable for referral to alternative low-acuity transport or referral options.

Enhancing predictions of patient conveyance using emergency call handler free text notes for unconscious and fainting incidents reported to the London Ambulance Service

OBJECTIVE

Pre-hospital emergency medical services use clinical decision support systems (CDSS) to triage calls. Call handlers often supplement this by making free text notes covering key incident information. We investigate whether machine learning approaches using features from such free text notes can improve prediction of unconscious patients who require conveyance.

MATERIALS AND METHODS

We analysed a subset of all London Ambulance Service calls that were triaged through the Medical Priority Dispatch System (MPDS) as involving an unconscious or fainting patient in 2018. We use and compare two machine learning algorithms: random forest (RF) and gradient boosting machine (GBM). For each incident, we predict whether the patient will be conveyed to a hospital emergency department or equivalent using as features 1) the MPDS code, 2) the free text notes and 3) the two together. We evaluate model performance using the area under the curve (AUC) metric. Given the imbalance of outcomes (patient conveyed 71 %, not conveyed 29 %), we also consider sensitivity and specificity.

RESULTS

Using only the MPDS code resulted in an AUC of 0.57. Using the text notes gave an improved AUC score of 0.63 and combining the two gave an AUC score of 0.64 (scores were similar for RF and GBM). GBM models scored better on sensitivity (0.93 vs 0.62 for RF in the combined model), but specificity was lower (0.17 vs. 0.56 for RF in the combined model).

CONCLUSIONS

Using information contained in the free text notes made by call handlers in combination with MPDS improves prediction of unconscious and fainting patients requiring conveyance to a hospital emergency department (or equivalent) when compared with machine learning models using MPDS codes only. This suggests there is some useful information in unstructured data captured by emergency call handlers that complements MPDS codes. Quantifying this gain can help inform emergency medical service policy when evaluating the decision to expand or augment existing CDSS.

Differences between cases admitted to hospital and discharged from the emergency department after emergency medical services transport

OBJECTIVE

Rising emergency medical services (EMS) utilisation increases transport to hospital emergency departments (ED). However, some patients receive outpatient treatment (discharged) while others are hospitalised (admitted). The aims of this analysis were to compare admitted and discharged cases, to assess whether cases that were discharged from the ED could be identified using dispatch data and to compare dispatch keyword categories and hospital diagnoses.

DESIGN

Retrospective observational study using linked secondary data.

SETTING AND PARTICIPANTS

78 303 cases brought to 1 of 14 ED in the city of Munich, Germany, by EMS between 1 July 2013 and 30 June 2014.

MAIN OUTCOME MEASURES

Characteristics of admitted and discharged cases were assessed. Logistic regression was used to estimate the association between discharge and age, sex, time of day, ambulance type and dispatch keyword category. Keyword categories were compared to hospital diagnoses.

RESULTS

39.4% of cases were discharged. They were especially likely to be young (OR 10.53 (CI 9.31 to 11.92), comparing <15-year-olds to >70-year-olds) and to fall under the categories 'accidents/trauma' (OR 2.87 (CI 2.74 to 3.01)) or 'other emergencies (unspecified)' (OR 1.23 (CI 1.12 to 1.34) (compared with 'cardiovascular'). Most frequent diagnoses came from chapter 'injury and poisoning' (30.1%) of the 10th revision of the international statistical classification of disease and related health problems (ICD-10), yet these diagnoses were more frequent at discharge (42.7 vs 22.0%) whereas circulatory system disease was less frequent (2.6 vs 21.8%). Except for accidents/trauma and intoxication/poisoning many underlying diagnoses were observed for the same dispatch keyword.

CONCLUSION

Young age and dispatch for accidents or trauma were the strongest predictors of discharge. Even within the same dispatch keyword category the distribution of diagnoses differed between admitted and discharged cases. Discharge from the ED does not indicate that urgent response was unnecessary. However, these cases could be suitable for allocation to hospitals with low inpatient bed capacities and are of particular interest for future studies regarding the urgency of their condition.

Ambulance dispatch versus general practitioner home visit for highly urgent out-of-hours primary care

BACKGROUND

Patients with life-threatening conditions who contact out-of-hours primary care either receive a home visit from a GP of a GP cooperative (GPC) or are handed over to the ambulance service.

OBJECTIVE

The objective of this study was to determine whether highly urgent visits, after a call to the GPC, are delivered by the most appropriate healthcare provider: GPC or ambulance service.

METHODS

We performed a cross-sectional study using patient record data from a GPC and ambulance service in an urban district in The Netherlands. During a 21-month period, all calls triaged as life-threatening (U1) to the GPCs were included. The decision to send an ambulance or not was made by the triage nurse following a protocolized triage process. Retrospectively, the most appropriate care was judged by the patient's own GP, using a questionnaire.

RESULTS

Patient and care characteristics from 1081 patients were gathered: 401 GPC visits, 570 ambulance responses and 110 with both ambulance and GPC deployment. In 598 of 1081 (55.3%) cases, questionnaires were returned by the patients' own GP. About 40% of all visits could have been carried out with a lower urgency in retrospect, and almost half of all visits should have received a different type of care or different provider. In case of ambulance response, 60.7% concerned chest pain.

CONCLUSION

Research should be done on the process of triage and allocation of care to optimize labelling complaints with the appropriate urgency and to deploy the appropriate healthcare provider, especially for patients with chest pain.

Non-urgent Emergency Callers: Characteristics and Prognosis

OBJECTIVE

In Denmark, calls to the Danish emergency number 1-1-2 concerning medical emergencies are received by an emergency medical communication center (EMCC). At the EMCC, health care professionals (nurses, paramedics, and physicians) decide the necessary response, depending on the level of emergency as indicated by the Danish Index for Emergency Care. The index states 37 main criteria (symptoms) and five levels of emergency, descending from A (life threatening) to E (not serious). An ambulance is not sent to emergency level-E patients (level-E patients), but they are given other kinds of help/advice. No prior studies focusing on Danish level-E patients exist, hence the sparse knowledge about them. This study aimed to characterize level-E patients in the Central Denmark Region and to investigate their progress in the health care system after the 1-1-2 call, regarding contacting 1-1-2 again, general practitioner and Emergency Department (ED) visits, hospital admission, and death.

METHODS

This is a retrospective follow-up study of callers who contacted the EMCC of the Central Denmark Region and were assessed as level-E patients from August 2013 to July 2014. The study population was identified in the EMCC dispatch software, whose data were supplemented with health care data from three national registries.

RESULTS

Of the 53,414 patients who called 1-1-2 over the study period, 4,962 level-E patients were included in the study. The median age was 47 years (IQR: 24.3-67.7), and 53.4% were men. The most common main criteria were extremity pain - minor wounds. Within 1 day after their 1-1-2 call, 42.1% had a subsequent contact with the health care system. Of those, 5.9% called 1-1-2 again, 24.3% contacted an ED, and 8.6% were admitted. The fatality rate was 0.1%.

CONCLUSIONS

Level-E patients who contacted the EMCC of the Central Denmark Region were most frequently young adults. Almost 60% of level E-patients, who could be tracked, had no further contact with the health care system within a day after their 1-1-2 call. Of those who did, a quarter contacted an ED, indicating that level-E patients needed medical attention. The low fatality rates suggest limited undertriage, that is, level-E patients do not seem to need emergency medical service transportation. Further studies on undertriage among other things are needed.

Factors Influencing the Timeliness of Emergency Medical Service Response to Time Critical Emergencies

OBJECTIVE

While emergency medical service (EMS) response times (ERT) remain a leading measure of system performance in many developed countries, relatively few studies have explored the factors associated with meeting benchmark performance for potentially time critical incidents. The purpose of this study was to identify system-level and patient-level factors associated with ERT, which are readily available at the time of ambulance dispatch.

METHODS

Between July 2009 and June 2014, we included data from 1,000,458 EMS responses to time critical "lights and sirens" incidents in Melbourne, Australia. The primary outcome measure was ERT, defined as the time from emergency call to the arrival of the first EMS team on scene. Quantile regression models were used to identify system-level and patient-level factors associated with 10-percentile intervals of ERT.

RESULTS

The median ERT was 10.6 minutes (IQR: 8.1-14.0), increasing from 9.6 minutes (IQR: 7.6-12.5) in 2009/10 to 11.0 minutes (IQR: 8.4-14.7) in 2013/14 (p < 0.001). System-level factors independently associated with the 90th percentile ERT were distance to scene, activation time, turnout time, case upgrade, hour of day, day of week, workload in the previous hour, ambulance skill set, priority zero case (e.g., suspected cardiac or respiratory arrest), and average hospital delay time in the previous hour. Patient-level factors such as age, gender, chief medical complaint, and severity of complaint were also significantly associated with ERT.

CONCLUSIONS

System-level and patient-level factors available at the time of ambulance dispatch are useful predictors of ERT performance, which could be used to improve the timeliness of EMS response.

Intentional drug poisoning care in a physician-manned emergency medical service

OBJECTIVES

Severely poisoned patients can benefit from intensive and specific treatments. Emergency medical services (EMS) may therefore play a crucial role by matching prehospital care and hospital referral to the severity of poisoned patients. Our aim was to investigate EMS accuracy in this condition.

METHODS

A 3-year retrospective study was conducted in a university hospital. Emergency telephone calls about adult patients with intentional drug poisoning (IDP) were included. In daily practice, an emergency physician answers such telephone calls and dispatches either first responders or a mobile intensive care unit (MICU). According to on-scene evaluation, patients are referred to the emergency department (ED) or to an intensive care unit (ICU). We therefore calculated global EMS accuracy according to patients' actual medical needs. We further evaluated the performance of dispatch and hospital referral decision. We also performed a regression analysis to identify factors of inappropriate dispatch.

RESULTS

A total of 2,227 patients were studied. Median age was 41 years old (range 30-49) and 63% were women. Dispatch was appropriate for 1,937 (87%) patients. Sensitivity and specificity of dispatch decision were 0.43 and 0.93, respectively. Decision of patients' referral to an appropriate hospital facility had a sensitivity of 0.67 and a specificity of 0.98. Toxicological data, age, and Glasgow coma scale were significantly associated with inappropriate EMS decisions.

CONCLUSIONS

A physician-operated EMS is an accurate system to provide prehospital care to IDP patients. However, dispatch physicians should pay attention, especially to toxicological anamnesis, to anticipate proper patient care.