Accuracy of dispatch and prehospital triage performance in poisonings - A retrospective study from northern Finland.

BACKGROUND: Increasing numbers of dispatches place a burden on EMS; this study sought to assess the prehospital evaluation of poisoned patients transported to hospital. The primary aim of this study was to measure dispatch centre and EMS provider performance as well as factors contributing to the recognition of poisoning among prehospital patients. The secondary aim was to compare triage performance between dispatch centres and EMS providers. METHODS: A retrospective single-centre study in Northern Finland was conducted. Patients suspected as poisonings by dispatch centres as well as other EMS-transported patients who received a diagnosis of poisoning in hospital between June 1, 2015 and June 1, 2017, were included. RESULTS: There were a total of 1668 poisoning-related EMS missions. Dispatch centres suspected poisonings with sensitivity of 79.9% (95% CI 76.7-82.9) and specificity of 98.9% (95% CI 98.9-99.0) when all EMS missions were taken into account. In a logistic regression model, decreased state of consciousness as dispatch code (OR 7.18, 95% CI 1.90-27.05) and intravenous fluid resuscitation (OR 6.58, 95% CI 1.34-32.37) were associated with EMS transport providers not recognizing poisoning. Overtriage rate appeared significantly higher (33.6%, 95% CI 28.6-39.2) for dispatch when compared with transport (17.8%, 95% CI 13.9-22.6). CONCLUSION: Dispatch centres seem to suspect poisonings fairly accurately. Poisonings unrecognized by EMS providers may be linked with intravenous fluid resuscitation and decreased patient consciousness. Overtriage appears to resolve somewhat from dispatch to transport. There were no fatal poisonings in this study population.

Cerebral oxygen desaturation events during and functional outcomes after prehospital anaesthesia: A prospective pilot study.

BACKGROUND: During prehospital anaesthesia, oxygen delivery to the brain might be inadequate to match the oxygen consumption, with unknown long-term functional outcomes. We aimed to evaluate the feasibility of monitoring cerebral oxygenation during prehospital anaesthesia and determining the long-term outcomes. METHODS: We performed a prospective observational feasibility study in two helicopter emergency medical services units. Frontal lobe regional oxygen saturation (rSO2 ) of adult patients undergoing prehospital anaesthesia was monitored with near-infrared spectroscopy (NIRS) by a Nonin H500 oximeter. The outcome was evaluated with a modified Rankin Scale (mRS) at 30 days and 1 year. Health-related quality of life (HRQoL) was measured with a 15D instrument at 1 year. RESULTS: Of 101 patients enrolled, 83 were included. The mean baseline rSO2 was 79% (73-84). Desaturation for at least 5 min to rSO2 below 50% or a decrease of 10% from baseline occurred in four (5%, 95% CI 2%-12%) and 19 (23%, 95% CI 15-93) patients. At 1 year, 32 patients (53%, 95% CI 41-65) achieved favourable neurological outcomes. The median 15D score was 0.889 (Q1-Q3, 0.796-0.970). CONCLUSION: Monitoring cerebral oxygenation with a hand-held oximeter during prehospital anaesthesia and collecting data on functional outcomes and HRQoL are feasible. Only half of the patients achieved a favourable functional outcome. The effects of cerebral oxygenation on outcomes during prehospital critical care need to be assessed in future studies.

Emergency department admission and mortality of the non-transported emergency medical service patients: a cohort study from Northern Finland.

OBJECTIVES: A high number of emergency medical service (EMS) patients are not transported to hospital by ambulance. Various non-transport protocols and guidelines have been implemented by different EMS providers. The present study examines subsequent tertiary care ED and hospital admission and mortality of the patients assessed and not transported by EMS in Northern Finland and evaluates the factors predicting these outcomes. METHODS: Data from EMS missions with a registered non-transportation code during 1 January 2018-31 December 2018 were screened retrospectively. EMS charts were retrieved from a local EMS database and data concerning hospital admission and mortality were collected from the medical records of Oulu University Hospital, Oulu, Finland. RESULTS: A total of 12 530 EMS non-transport missions were included. Of those, a total of 344 (2.7%) patients were admitted to tertiary care ED in 48 hours after the EMS contact, and 229 (1.8%) of them were further admitted to the hospital. Patients with the dispatch code 'abdominal pain', clinical presentation with fever or hyperglycaemia, physician phone consultation and a decision not to transport during night hours were associated with a higher risk of ED admission within 48 hours after EMS contact. Overall 48-hour and 30-day mortalities of non-transported patients were 0.2% (n=25) and 1.0% (n=128), respectively. CONCLUSION: In this cohort, the rate of subsequent tertiary care ED admission and mortality in the non-transported EMS patients was low. Dispatch code abdominal pain, clinical presentation with fever or hyperglycaemia, physician phone consultation and night-hours increased the risk of ED admission within 48 hours after EMS contact.

The effect of time of measurement on the discriminant ability for mortality in trauma of a pre-hospital shock index multiplied by age and divided by the Glasgow Coma Score: a registry study.

BACKGROUND: The shock index (SI) and its derivatives have been shown to predict mortality in severely injured patients, both in pre-hospital and in-hospital settings. However, the impact of the time of measurement on the discriminative ability of the pre-hospital SI is unknown. The aim of this study was to evaluate whether the time of measurement influences the discriminative ability of the SI multiplied by age (SIA) and divided by the Glasgow Coma Score (SIA/G). METHODS: Registry data were obtained from the national helicopter emergency medical services (HEMS) on trauma patients aged ≥ 18 years. The SI values were calculated based on the first measured vitals of the trauma patients by the HEMS unit. The discriminative ability of the SIA/G, with 30-day mortality as the endpoint, was evaluated according to different delay times (0 - 19, 20 - 39 and ≥ 40 min) from the initial incident. Sub-group analyses were performed for trauma patients without a traumatic brain injury (TBI), patients with an isolated TBI and patients with polytrauma, including a TBI. RESULTS: In total, 3,497 patients were included in the study. The SIA/G was higher in non-survivors (median 7.8 [interquartile range 4.7-12.3] vs. 2.4 [1.7-3.6], P < 0.001). The overall area under the receiver operator characteristic curve (AUROC) for the SIA/G was 0.87 (95% CI: 0.85-0.89). The AUROC for the SIA/G was similar in the short (0.88, 95% CI: 0.85-0.91), intermediate (0.86, 95% CI: 0.84-0.89) and long (0.86, 95% CI: 0.82-0.89) measurement delay groups. The findings were similar in the three trauma sub-groups. CONCLUSIONS: The discriminative ability of the SIA/G in predicting 30-day mortality was not significantly affected by the measurement time of the index in the pre-hospital setting. The SIA/G is a simple and reliable tool for assessing the risk of mortality among severely injured patients in the pre-hospital setting.

Epidemiology of trauma in the subarctic regions of the Nordic countries.

BACKGROUND: The northern regions of the Nordic countries have common challenges of sparsely populated areas, long distances, and an arctic climate. The aim of this study was to compare the cause and rate of fatal injuries in the northernmost area of the Nordic countries over a 5-year period. METHODS: In this retrospective cohort, we used the Cause of Death Registries to collate all deaths from 2007 to 2011 due to an external cause of death. The study area was the three northernmost counties in Norway, the four northernmost counties in Finland and Sweden, and the whole of Iceland. RESULTS: A total of 4308 deaths were included in the analysis. Low energy trauma comprised 24% of deaths and high energy trauma 76% of deaths. Northern Finland had the highest incidence of both high and low energy trauma deaths. Iceland had the lowest incidence of high and low energy trauma deaths. Iceland had the lowest prehospital share of deaths (74%) and the lowest incidence of injuries leading to death in a rural location. The incidence rates for high energy trauma death were 36.1/100000/year in Northern Finland, 15.6/100000/year in Iceland, 27.0/100000/year in Northern Norway, and 23.0/100000/year in Northern Sweden. CONCLUSION: We found unexpected differences in the epidemiology of trauma death between the countries. The differences suggest that a comparison of the trauma care systems and preventive strategies in the four countries is required.

Shock index as a predictor for short-term mortality in helicopter emergency medical services: A registry study.

BACKGROUND: The value of shock-index has been demonstrated in hospital triage, but few studies have evaluated its prehospital use. The aim of our study was to evaluate the association between shock-index in prehospital critical care and short-term mortality. METHODS: We analyzed data from the national helicopter emergency medical services database and the Population Register Centre. The shock-index was calculated from the patients' first measured parameters. The primary outcome measure was 1- and 30-day mortality. RESULTS: A total of 22 433 patients were included. The 1-day mortality was 7.5% and 30-day mortality was 16%. The median shock-index was 0.68 (0.55/0.84) for survivors and 0.67 (0.49/0.93) for non-survivors (P = .316) at 30-days. Association between shock-index and mortality followed a U-shaped curve in trauma (shock-index < 0.5: odds ratio 2.5 [95% confidence interval 1.8-3.4], shock-index > 1.3: odds ratio 4.4 [2.7-7.2] at 30 days). Patients with neurological emergencies with a low shock-index had an increased risk of mortality (shock-index < 0.5: odds ratio 1.8 [1.5-2.3]) whereas patients treated after successful resuscitation from out-of-hospital cardiac arrest, a higher shock-index was associated with higher mortality (shock-index > 1.3: odds ratio 3.5 [2.3-5.4). The association was similar for all ages, but older patients had higher mortality in each shock-index category. CONCLUSION: The shock-index is associated with short time mortality in most critical patient categories in the prehospital setting. However, the marked overlap of shock-index in survivors and non-survivors in all patient categories limits its predictive value.

Early impact of the COVID-19 pandemic and social restrictions on ambulance missions.

BACKGROUND: The SARS-CoV-2 coronavirus disease 2019 (COVID-19) has had a major impact on health care services globally. Recent studies report that emergency departments have experienced a significant decline in the number of admitted patients in the early phase of the pandemic. To date, research regarding the influence of COVID-19 on emergency medical services (EMS) is limited. This study investigates a change in the number and characteristics of EMS missions in the early phase of the pandemic. METHODS: All EMS missions in the Northern Ostrobothnia region, Finland (population 295 500) between 1 March to 30 June 2020 were screened and analyzed as the study group. A control group was composed from the EMS calls between the corresponding months in the years 2016-19. RESULTS: A total of 74 576 EMS missions were screened for the study. Within the first 2 months after the first COVID-19 cases in the study area, the decline in the number of EMS missions was 5.7-13% compared with the control group average. EMS time intervals (emergency call to dispatch, dispatch, en-route, on-scene and hospital handover) prolonged in the COVID-19 period. Dispatches concerning mental health problems increased most in the study period (+1.2%, P < 0.001). Only eleven confirmed COVID-19 infections were encountered by EMS in the study period. CONCLUSION: Our findings suggest that the present COVID-19 pandemic and social restrictions lead to changes in the EMS usage. These preliminary findings emphasize the importance of developing new strategies and protocols in response to the oncoming pandemic waves.

An analysis of prehospital critical care events and management patterns from 97 539 emergency helicopter medical service missions: A retrospective registry-based study.

BACKGROUND: It is largely unknown how often physicians in emergency helicopter medical services (HEMS) encounter various critical care events and if HEMS exposure is associated with particular practice patterns or outcomes. OBJECTIVES: This study aimed: to describe the frequency and distribution of critical care events; to investigate whether HEMS exposure is associated with differences in practice patterns and determine if HEMS exposure factors are associated with mortality. DESIGN: A retrospective registry-based study. SETTING: Physician-staffed HEMS in Finland between January 2012 and August 2019. PARTICIPANTS: Ninety-four physicians who worked at least 6 months in the HEMS during the study period. Physicians with undeterminable HEMS exposure were excluded from practice pattern comparisons and mortality analysis, leaving 80 physicians. MAIN OUTCOME MEASURES: The primary outcome measure was a physician's average annual frequencies for operational events and clinical interventions. Our secondary outcomes were the proportion of missions cancelled or denied, time onsite (OST) and proportion of unconscious patients intubated. Our tertiary outcome was adjusted 30-day mortality of patients. RESULTS: The physicians encountered 62 [33 to 98], escorted 31 [17 to 41] and transported by helicopter 2.1 [1.3 to 3.5] patients annually, given as median [interquartile range; IQR]. Rapid sequence intubation was performed 11 [6.2 to 16] times per year. Physicians were involved in out-of-hospital cardiac arrest (OHCA) 10 [5.9 to 14] and postresuscitation care 5.5 [3.1 to 8.1] times per year. Physicians with longer patient intervals had shorter times onsite. Proportionally, they cancelled more missions and intubated fewer unconscious patients. A short patient interval [odds ratio (OR); 95% confidence interval (CI)] was associated with decreased mortality (0.87; 95% CI, 0.76 to1.00), whereas no association was observed between mortality and HEMS career length. CONCLUSION: Prehospital exposure is distributed unevenly, and some physicians receive limited exposure to prehospital critical care. This seems to be associated with differences in practice patterns. Rare HEMS patient contacts may be associated with increased mortality.

Telephone triage performed by nurses reduces non-urgent ambulance missions: A prospective observational pilot study in Finland.

BACKGROUND: The increased workload in emergency medical services (EMS) is a global phenomenon in welfare states. It has been suggested that telephone triage by nurses may reduce the increasing use of EMS services, by directing patient flow to appropriate care. This study aimed to investigate whether, after an emergency medical communication centre (EMCC) provider assessed risk, a telephone nurse could assess the patient's needs and guide patients to social and health care services in non-urgent cases. METHODS: This prospective observational study was performed in the Kainuu Hospital District in northern Finland from March to April 2018. All EMS requests classified as non-urgent by the EMCC were transferred to a telephone triage nurse. Subsequent patient guidance was recorded. The International Classifications of Primary Care categories were recorded. RESULTS: We studied phone calls of 700 patients with non-urgent needs. Of these, the nurse transferred 63.7% to EMS and 17.3% were guided to other social and health care services. Nineteen per cent of the calls were handled over the phone by the nurse, who provided health advice and instructions. The most common needs for care were general and unspecified symptoms, musculoskeletal symptoms, mental health problems and substance abuse. CONCLUSION: By providing telephone counseling, care instructions and patient guidance to other social and health services than EMS, the telephone triage reduced non-urgent EMS missions by one third. The results imply that telephone triage could be a viable model for managing non-urgent missions. Patient safety issues should be monitored when developing new service concepts.

Femoral nerve blocks for the treatment of acute pre-hospital pain: A systematic review with meta-analysis.

BACKGROUND: Pain management is one of the most important interventions in the emergency medical services. The femoral nerve block (FNB) is, among other things, indicated for pre- and post-operative pain management for patients with femoral fractures but its role in the pre-hospital setting has not been determined. The aim of this review was to assess the effect and safety of the FNB in comparison to other forms of analgesia (or no treatment) for managing acute lower extremity pain in adult patients in the pre-hospital setting. METHODS: A systematic review (PROSPERO registration (CRD42018114399)) was conducted. The Cochrane and GRADE methods were used to assess outcomes. Two authors independently reviewed each study for eligibility, extracted the data and performed risk of bias assessments. RESULTS: Four studies with a total of 252 patients were included. Two RCTs (114 patients) showed that FNB may reduce pain more effectively than metamizole (mean difference 32 mm on a 100 mm VAS (95% CI 24 to 40)). One RCT (48 patients) compared the FNB with lidocaine and magnesium sulphate to FNB with lidocaine alone and was only included here for information regarding adverse effects. One case series included 90 patients. Few adverse events were reported in the included studies. The certainty of evidence was very low. We found no studies comparing FNB to inhaled analgesics, opioids or ketamine. CONCLUSIONS: Evidence regarding the effectiveness and adverse effects of pre-hospital FNB is limited. Studies comparing pre-hospital FNB to inhaled analgesics, opioids or ketamine are lacking.

How does socioeconomic status affect the incidence of hospital-treated poisonings? A retrospective study.

BACKGROUND: Hospital-treated poisonings have a good outcome in general. The role of regional differences and socioeconomic status has been established in intensive care admissions and various causes of death, but not yet in hospital-treated poisonings. We set out to determine whether the incidence of hospital-treated poisonings is affected by the annual income of the residential area. METHODS: All poisonings in Northern Ostrobothnia region of Finland treated in Oulu University Hospital during 2013-2016 were studied. Oulu University Hospital is the primary hospital in the area. Postal code areas of the county were categorized on the basis of their median annual net income as low-, middle- and high-income areas. RESULTS: A total of 2142 poisoning cases were studied. The number of individual patients was 1525. In the low-income areas, the crude incidence of poisonings was more than 2-fold when compared with the middle- and high-income areas. In adolescents aged 13 to 17 years, the incidence in the low-income areas was almost 3-fold compared with the other two categories at 335/100 000/year (95% CI, 236-463). Four patients (0.2%) died during the hospital stay and 50 patients (2.3%) died within 6 months from the last admission. CONCLUSIONS: The incidence of hospital-treated poisoning was at least 2-fold in low-income areas when compared with middle- or high-income areas. For adolescent population from 13 to 17 years, the incidence in low-income areas was almost 3-fold when compared with other areas.

Use of prehospital emergency medical services according to income of residential area.

BACKGROUND: The increasing usage of emergency medical services (EMS) missions is a challenge in modern practice. This study was designed to examine the association of the income level of residential areas on the rate of EMS missions and the frequency of EMS use in these areas. METHODS: All EMS missions for adult patients (>18 years) encountered by one rescue department in Northern Finland between June 2015 and May 2017 were analysed. The area served was categorised into four categories, according to the median annual income of the postal code areas. EMS missions per 1000 person-years, rate of non-transport missions and the number of dispatches to frequent (>4 EMS calls/year and highly frequent (>10 calls/year)EMS users per area were investigated. RESULTS: There were 62 759 EMS missions, 34.8% of which resulted in non-transport. The crude rate of EMS dispatches was higher in the low-income area compared with other income areas (133.3 vs 108.9 vs 111.3 vs 73.6/1000 person-years) as well as the rate of high-frequency user dispatches (21.5 vs 11.5 vs 7.2 vs 4.3/1000-person years). The rate of non-transports missions was higher also (69.4 vs 43.4 vs 42.5. vs 30.6/1000 person-years). The highest crude rate of EMS use was found in people older than 65 years living in the lowest income areas (294.8/1000 person-years). After age adjustment, the highest rate of EMS use was found in rural areas with the lowest income (146.3/1000 person-years). CONCLUSIONS: The rate of the EMS missions and non-transport missions differs significantly among different income areas. Resource usage was significantly higher in the low income areas. This information can be used in planning allocation of EMS and preventive healthcare resources.

Factors related to delayed intensive care unit admission from emergency department-A retrospective cohort study.

BACKGROUND: The delays in transferring patients from emergency department (ED) to intensive care unit (ICU) are known to be linked with several adverse events, including prolonged ICU stay and increased hospital mortality. The factors associated with delayed ICU admission include shortage of ICU beds, organizational factors, ED overcrowding, and patient-related factors, including sepsis as admission diagnosis. The aim of this study was to examine ED-related factors associated with prolonged ED stay. METHODS: The study population consisted of adult patients admitted (n = 479) from ED to ICU between 31 May 2016 and 19 March 2017 in Oulu University Hospital. A patient's ED length of stay (LOS) exceeding 180 minutes was considered delayed. RESULTS: Most of the patients (380, 79.3%) were admitted to the ICU within 3 hours of hospital admission. In a logistic regression analysis, odds ratios (ORs) for ED LOS > 180 minutes were as follows: for Glasgow Coma Scale score > 9, 2.73 (1.39-5.32); for thrombocytes < 100 × 109 /mmol, 6.69 (2.32-19.26); for absence of pre-arrival notification, 5.27 (3.04-9.14); and for radiological examination, 3.95 (1.72-9.10). Trauma and intoxicated patients had shorter ED LOS while patients with medical conditions had more often prolonged admissions. CONCLUSION: The delays in ICU admissions were linked to therapeutic and diagnostic procedures and absence of pre-arrival notification. Patients were admitted to the ICU on the basis of diagnosis instead of clinical risk. However, the delays were not associated with worsening outcome, which indicates that sufficient care can be provided at the ED while the ICU admission is pending.

Correction to: Systematic reporting to improve the emergency medical response to major incidents: a pilot study.

ERRATUM: The original article [1] contains an error whereby all authors' names were mistakenly interchanged. The original article has now been corrected to present the authors' names correctly.

Systematic reporting to improve the emergency medical response to major incidents: a pilot study.

BACKGROUND: Major incidents affect us globally, and are occurring with increasing frequency. There is still no evidence-based standard regarding the best medical emergency response to major incidents. Currently, reports on major incidents are non-standardised and variable in quality. This pilot study examines the first systematic reports from a consensus-based, freely accessible database, aiming to identify how descriptive analysis of reports submitted to this database can be used to improve the major incident response. METHODS: Majorincidentreporting.net is a website collecting reports on major incidents using a standardised template. Data from these reports were analysed to compare the emergency response to each incident. RESULTS: Data from eight reports showed that effective triage by experienced individuals and the use of volunteers for transport were notable successes of the major incident response. Inadequate resources, lack of a common triage system, confusion over command and control and failure of communication were reported failures. The following trends were identified: Fires had the slowest times for several aspects of the response and the only three countries to have a single dialling number for all three emergency services had faster response times. Helicopter Emergency Medical services (HEMS) were used for transport and treatment in rural locations and for triage and treatment in urban locations. In two incidents, a major incident was declared before the arrival of the first Emergency Medical Services (EMS) personnel. CONCLUSION: This study shows that we can obtain relevant data from major incidents by using systematic reporting. Though the sample size from this pilot study is not large enough to draw any specific conclusions it illustrates the potential for future analyses. Identified lessons could be used to improve the emergency medical response to major incidents.

Drip-and-ship stroke thrombolysis in the emergency department of a healthcare center - a possibility for those fallen ill in rural settings.

Thrombolysis with tissue plasminogen activator is the mainstay in the treatment of acute stroke. Reducing the delay of thrombolysis treatment improves patient prognosis and reduces the incidence of complications. Variable telestroke regimens have improved the availability of stroke thrombolysis, especially in rural settings, where neurologists are not readily available. In the drip-and-ship strategy, stroke thrombolysis is initiated in a peripheral hospital and the patient is then transferred to a tertiary care unit. We report the first case of drip-and-ship stroke thrombolysis in a rural health care center in Northeastern Finland.

[Transluminal coronary angioplasty during resuscitation--an option not to be ignored]. / Elvytyksen aikainen sepelvaltimon pallolaajennushoito--mahdollisuus, joka tulisi muistaa.

We describe a prolonged and successful in-hospital resuscitation, during which the cause of cardiac arrest was treated by transluminal coronary angioplasty. A closed cardiac massage device was used in the resuscitation of the patient, and the treatment required close collaboration between the cardiologist and the resuscitation team. In spite of the difficult initial situation and several disturbances of vital functions the patient was discharged in good condition.

Front of neck airway in Finnish helicopter emergency medical services.

INTRODUCTION: An emergent front of neck airway (FONA) is needed when a 'can't intubate, can't oxygenate' crisis occurs. A FONA may also in specific cases be the primary choice of airway management. Two techniques exist for FONA, with literature favouring the surgical technique over the percutaneous. The reported need for a prehospital FONA is fortunately rare as the mortality has been shown to be high. Due to the low incidence, literature on FONA is limited with regards to different settings, techniques and operators. As a foundation for future research and improvement of patient care, we aim to describe the frequency, indications, technique, success, and outcomes of FONA in the Finnish helicopter emergency medical services (HEMS). MATERIALS AND METHODS: This retrospective descriptive study reviews FONA performed at the Finnish HEMS during 1.1.2012 to 8.9.2019. The Finnish HEMS consists of six units, staffed mainly by anaesthesiologists. Clinical data was gathered from a national HEMS database and trough chart reviews. Data on mortality was obtained from a population registry. Only descriptive statistics were performed. RESULTS: A total of 22 FONA were performed during the study period, 7 were primary and 14 performed after failure to intubate (missing data regarding indication for one attempt). This equals a 0.13 % (14/10,813) need for a rescue FONA and a rate of 0.20 % (22/10,813) FONA out of all advanced airway management. All but one FONA was performed using a surgical approach (20/21, 95 %, missing data = 1) and all were successful (22/22, 100 %). Indications were mainly cardiac arrest (10/22, 45 %) and trauma (6/22, 27 %), and the most common reason for a need for a secondary FONA was obstruction of airway by food or fluids (7/14, 50 %). On-scene mortality was 36 % (8/22) and 30-day mortality 90 % (19/21, missing data = 1). CONCLUSION: The need for FONA is scarce in a HEMS system with experienced airway providers. Even though the procedure is successfully performed, the mortality is markedly high.

Development and internal validation of an algorithm for estimating mortality in patients encountered by physician-staffed helicopter emergency medical services.

BACKGROUND: Severity of illness scoring systems are used in intensive care units to enable the calculation of adjusted outcomes for audit and benchmarking purposes. Similar tools are lacking for pre-hospital emergency medicine. Therefore, using a national helicopter emergency medical services database, we developed and internally validated a mortality prediction algorithm. METHODS: We conducted a multicentre retrospective observational register-based cohort study based on the patients treated by five physician-staffed Finnish helicopter emergency medical service units between 2012 and 2019. Only patients aged 16 and over treated by physician-staffed units were included. We analysed the relationship between 30-day mortality and physiological, patient-related and circumstantial variables. The data were imputed using multiple imputations employing chained equations. We used multivariate logistic regression to estimate the variable effects and performed derivation of multiple multivariable models with different combinations of variables. The models were combined into an algorithm to allow a risk estimation tool that accounts for missing variables. Internal validation was assessed by calculating the optimism of each performance estimate using the von Hippel method with four imputed sets. RESULTS: After exclusions, 30 186 patients were included in the analysis. 8611 (29%) patients died within the first 30 days after the incident. Eleven predictor variables (systolic blood pressure, heart rate, oxygen saturation, Glasgow Coma Scale, sex, age, emergency medical services vehicle type [helicopter vs ground unit], whether the mission was located in a medical facility or nursing home, cardiac rhythm [asystole, pulseless electrical activity, ventricular fibrillation, ventricular tachycardia vs others], time from emergency call to physician arrival and patient category) were included. Adjusted for optimism after internal validation, the algorithm had an area under the receiver operating characteristic curve of 0.921 (95% CI 0.918 to 0.924), Brier score of 0.097, calibration intercept of 0.000 (95% CI -0.040 to 0.040) and slope of 1.000 (95% CI 0.977 to 1.023). CONCLUSIONS: Based on 11 demographic, mission-specific, and physiologic variables, we developed and internally validated a novel severity of illness algorithm for use with patients encountered by physician-staffed helicopter emergency medical services, which may help in future quality improvement.