Using machine learning to assess the extent of busy ambulances and its impact on ambulance response times: A retrospective observational study.

BACKGROUND: Ambulance response times are considered important. Busy ambulances are common, but little is known about their effect on response times. OBJECTIVE: To assess the extent of busy ambulances in Central Norway and their impact on ambulance response times. DESIGN: This was a retrospective observational study. We used machine learning on data from nearby incidents to assess the probability of up to five different ambulances being candidates to respond to a medical emergency incident. For each incident, the probability of a busy ambulance was estimated by summing the probabilities of candidate ambulances being busy at the time of the incident. The difference in response time that may be attributable to busy ambulances was estimated by comparing groups of nearby incidents with different estimated busy probabilities. SETTING: Medical emergency incidents with ambulance response in Central Norway from 2013 to 2022. MAIN OUTCOME MEASURES: Prevalence of busy ambulances and differences in response times associated with busy ambulances. RESULTS: The estimated probability of busy ambulances for all 216,787 acute incidents with ambulance response was 26.7% (95% confidence interval (CI) 26.6 to 26.9). Comparing nearby incidents, each 10-percentage point increase in the probability of a busy ambulance was associated with a delay of 0.60 minutes (95% CI 0.58 to 0.62). For incidents in rural and urban areas, the probability of a busy ambulance was 21.6% (95% CI 21.5 to 21.8) and 35.0% (95% CI 34.8 to 35.2), respectively. The delay associated with a 10-percentage point increase in busy probability was 0.81 minutes (95% CI 0.78 to 0.84) and 0.30 minutes (95% CI 0.28 to 0.32), respectively. CONCLUSION: Ambulances were often busy, which was associated with delayed ambulance response times. In rural areas, the probability of busy ambulances was lower, although the potentially longer delays when ambulances were busy made these areas more vulnerable.

The introduction of a regional Norwegian HEMS coordinator: an assessment of the effects on response times, geographical service areas and severity scores.

BACKGROUND: Due to unwanted delays and suboptimal resource control of helicopter emergency medical services (HEMS), regional HEMS coordinators have recently been introduced in Norway. This may represent an unnecessary link in the alarm chain, which could cause delays in HEMS dispatch. Systematic evaluations of this intervention are lacking. We wanted to conduct this study to assess possible changes in HEMS response times, mission distribution patterns and patient characteristics within our region following this intervention. METHODS: We retrospectively collected timeline parameters, patient characteristics and GPS positions from HEMS missions executed by three regional HEMS bases in Mid-Norway during 2017-2018 (preintervention) and 2019 (postintervention). The mean regional response time in HEMS missions was assessed by an interrupted time series analysis (ITS). The geographical mission distribution between regional HEMS resources was assessed by a before-after study with a convex hull-based method. RESULTS: There was no significant change in the level (-0.13 min/month, p = 0.88) or slope (-0.13 min/month, p = 0.30) of the mean regional response time trend line pre- and postintervention. For one HEMS base, the service area was increased, and the median mission distance was significantly longer. For the two other bases, the service areas were reduced. Both the mean NACA score (4.13 ± SD 0.027 vs 3.98 ± SD 0.04, p < 0.01) and the proportion of patients with severe illness or injury (NACA 4-7, 68.2% vs 61.5%, p < 0.001) were higher in the postintervention group. CONCLUSION: The introduction of a regional HEMS coordinator in Mid-Norway did not cause prolonged response times in acute HEMS missions during the first year after implementation. Higher NACA scores in the patients treated postintervention suggest better selection of HEMS use.

Needs assessment of resuscitative endovascular balloon occlusion of the aorta (REBOA) in patients with major haemorrhage: a cross-sectional study.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) can be used as an adjunct treatment in traumatic abdominopelvic haemorrhage, ruptured abdominal aortic aneurysms, postpartum haemorrhage (PPH), gastrointestinal bleeding and iatrogenic injuries during surgery. This needs assessment study aims to determine the number of patients eligible for REBOA in a typical Norwegian population. METHODS: This was a retrospective cross-sectional study based on data obtained from blood bank registries and the Norwegian Trauma Registry for the years 2017-2018. Patients who received ≥4 units of packed red blood cells (PRBCs) within 6 hours and met the anatomical criteria for REBOA or patients with relevant Abbreviated Injury Scale codes with concurrent hypotension or transfusion of ≥4 units of PRBCs within 6 hours were identified. A detailed two-step chart review was performed to identify potentially eligible REBOA candidates. Descriptive data were collected and compared between subgroups using non-parametric tests for statistical significance. RESULTS: Of 804 patients eligible for inclusion, 53 patients were regarded as potentially REBOA eligible (corresponding to 5.7 per 100 000 adult population/year). Of these, 19 actually received REBOA. Among the identified eligible patients, 44 (83%) had a non-traumatic aetiology. Forty-two patients (79%) were treated at a tertiary care hospital. Fourteen (78%) of the REBOA procedures were due to PPH. CONCLUSION: The number of patients potentially eligible for REBOA after haemorrhage is low, and most cases are non-traumatic. Most patients were treated at a tertiary care hospital. The exclusion of non-traumatic patients results in a substantial underestimation of the number of potentially REBOA-eligible patients.

Changes in peripheral arterial blood pressure after resuscitative endovascular balloon occlusion of the aorta (REBOA) in non-traumatic cardiac arrest patients.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) may be an adjunct treatment to cardiopulmonary resuscitation (CPR). Aortic occlusion may increase aortic pressure and increase the coronary perfusion pressure and the cerebral blood flow. Peripheral arterial blood pressure is often measured during or after CPR, however, changes in peripheral blood pressure after aortic occlusion is insufficiently described. This study aimed to assess changes in peripheral arterial blood pressure after REBOA in patients with out of hospital cardiac arrest. METHODS: A prospective observational study performed at the helicopter emergency medical service in Trondheim (Norway). Eligible patients received REBOA as adjunct treatment to advanced cardiac life support. Peripheral invasive arterial blood pressure and end-tidal CO2 (EtCO2) was measured before and after aortic occlusion. Differences in arterial blood pressures and EtCO2 before and after occlusion was analysed with Wilcoxon Signed Rank test. RESULTS: Five patients were included to the study. The median REBOA procedural time was 11 min and median time from dispatch to aortic occlusion was 50 min. Two patients achieved return of spontaneous circulation. EtCO2 increased significantly 60 s after occlusion, by a mean of 1.16 kPa (p = 0.043). Before occlusion the arterial pressure in the compression phase were 43.2 (range 12-112) mmHg, the mean pressure 18.6 (range 4-27) mmHg and pressure in the relaxation phase 7.8 (range - 7 - 22) mmHg. After aortic occlusion the corresponding pressures were 114.8 (range 23-241) mmHg, 44.6 (range 15-87) mmHg and 14.8 (range 0-29) mmHg. The arterial pressures were significant different in the compression phase and as mean pressure (p = 0.043 and p = 0.043, respectively) and not significant in the relaxation phase (p = 0.223). CONCLUSION: This study is, to our knowledge, the first to assess the peripheral invasive arterial blood pressure response to aortic occlusion during CPR in the pre-hospital setting. REBOA application during CPR is associated with a significantly increase in peripheral artery pressures. This likely indicates improved central aortic blood pressure and warrants studies with simultaneous peripheral and central blood pressure measurement during aortic occlusion. TRIAL REGISTRATION: The study is registered in ClinicalTrials.gov ( NCT03534011 ).

REBOARREST, resuscitative endovascular balloon occlusion of the aorta in non-traumatic out-of-hospital cardiac arrest: a study protocol for a randomised, parallel group, clinical multicentre trial.

BACKGROUND: Survival after out-of-hospital cardiac arrest (OHCA) is poor and dependent on high-quality cardiopulmonary resuscitation. Resuscitative endovascular balloon occlusion of the aorta (REBOA) may be advantageous in non-traumatic OHCA due to the potential benefit of redistributing the cardiac output to organs proximal to the aortic occlusion. This theory is supported by data from both preclinical studies and human case reports. METHODS: This multicentre trial will enrol 200 adult patients, who will be randomised in a 1:1 ratio to either a control group that receives advanced cardiovascular life support (ACLS) or an intervention group that receives ACLS and REBOA. The primary endpoint will be the proportion of patients who achieve return of spontaneous circulation with a duration of at least 20 min. The secondary objectives of this trial are to measure the proportion of patients surviving to 30 days with good neurological status, to describe the haemodynamic physiology of aortic occlusion during ACLS, and to document adverse events. DISCUSSION: Results from this study will assess the efficacy and safety of REBOA as an adjunctive treatment for non-traumatic OHCA. This novel use of REBOA may contribute to improve treatment for this patient cohort. TRIAL REGISTRATION: The trial is approved by the Regional Committee for Medical and Health Research Ethics in Norway (reference 152504) and is registered at ClinicalTrials.gov (reference NCT04596514) and as Universal Trial Number WHO: U1111-1253-0322.

Developing Quality Indicators for Helicopter Emergency Medical Services Coordination in Norwegian Emergency Medical Communication Centrals: A Consensus Process.

OBJECTIVE: Efforts to optimize the use, availability, and safety of helicopter emergency medical services (HEMS) is important. A lack of consistent and comprehensive flight dispatch procedures and a lack of use of safety technology are recurring safety problems. Reports after several major incidents pointed toward a possible gain by coordinating Norwegian HEMS from regional emergency medical communication centrals. Our objective was to develop and implement relevant quality indicators before such implementation in central Norway. METHODS: We recruited an expert panel of 24 persons representing Norwegian health authorities, emergency medical communication centrals, and HEMS bases and performed a 3-step e-mail-based Delphi process to develop relevant quality indicators. Each indicator was assessed according to their feasibility, rankability, actionability, and variability. To reach a consensus, a median score of 5 or more on a 6-point Likert scale in step 3 was needed. RESULTS: A total of 61 quality indicators were proposed. Of the 14 indicators that reached a consensus, 12 of these were considered process indicators, and 2 were bordering to outcome indicators. CONCLUSION: We applied a Delphi process method to develop quality indicators for HEMS coordination and flight following. An experienced and heterogeneous expert panel suggested and reached a consensus on which quality indicators should be applied.

Pediatric hypothermic submersion incident - should we do chest compressions on a beating heart?

BACKGROUND: Drowning is the third leading cause of unintentional injury death worldwide, with the highest rates of fatality among young children. To decide how to treat these patients prehospitally could be challenging in certain situations when uncertain about the adequacy of the patent's circulation. METHODS/CASE REPORT: We describe a 2 year old boy surviving a 15 min hypothermic submersion in a cold river. In spite of the presence of some vital signs, we decided to do full cardiopulmonary resuscitation to the hospital. The main reason was that we were uncertain about the adequacy of the spontaneous circulation, and the transport to hospital was fairly long. The patient suffered no obvious harm and the outcome was good. DISCUSSION: What is regarded as adequate circulation when accidentally hypothermic between 24 and 250 C? A weak pulse was felt in the femoral artery with a rate of about 40-50 per minute. There were shallow, but regular respiration, and point of care ultrasound revealed a slightly dilated left ventricle and weak, but organised cardiac contractions. Despite these findings a decision was made to continue ventilations and chest compressions during helicopter transport to the University hospital. CONCLUSION: In an accidentally hypothermic pediatric submersion incident we decided to do full cardiopulmonary resuscitation to the hospital despite there were signs of circulation. We did no harm to the patient. Future guideline revisions should try to clarify how to handle situations with severly accidentally hypothermic patients like this, so the good outcome that is often seen in these patients could be even better.

Template for documenting and reporting data in physician-staffed pre-hospital services: a consensus-based update.

BACKGROUND: Physician-staffed emergency medical services (p-EMS) are resource demanding, and research is needed to evaluate any potential effects of p-EMS. Templates, designed through expert agreement, are valuable and feasible, but they need to be updated on a regular basis due to developments in available equipment and treatment options. In 2011, a consensus-based template documenting and reporting data in p-EMS was published. We aimed to revise and update the template for documenting and reporting in p-EMS. METHODS: A Delphi method was applied to achieve a consensus from a panel of selected European experts. The experts were blinded to each other until a consensus was reached, and all responses were anonymized. The experts were asked to propose variables within five predefined sections. There was also an optional sixth section for variables that did not fit into the pre-defined sections. Experts were asked to review and rate all variables from 1 (totally disagree) to 5 (totally agree) based on relevance, and consensus was defined as variables rated ≥4 by more than 70% of the experts. RESULTS: Eleven experts participated. The experts generated 194 unique variables in the first round. After five rounds, a consensus was reached. The updated dataset was an expanded version of the original dataset and the template was expanded from 45 to 73 main variables. The experts approved the final version of the template. CONCLUSIONS: Using a Delphi method, we have updated the template for documenting and reporting in p-EMS. We recommend implementing the dataset for standard reporting in p-EMS.

Epidemiology of paediatric trauma in Norway: a single-trauma centre observational study.

BACKGROUND: Trauma is a major cause of mortality and morbidity in children globally. The burden of injury shows substantial geographical differences, with a significant mortality reduction in children in Norway during the last four decades. The aim was to describe the current epidemiology, resource use and outcome for all potential severely injured paediatric patients admitted to a Norwegian trauma centre. METHODS: This was a single-centre retrospective observational study. All patients aged 0-17 years received by a trauma team between 01 January 2004 and 31 December 2016 (13 years) at St. Olav's University Hospital were included. Severe injury was defined as Injury Severity Score > 15. RESULTS: A total of 873 patients were included, of which 536 (61%) were male. The median age was 13 years (IQR 7-16). Six per cent (n = 52) of the patients were transferred from other hospitals. Blunt trauma constituted 98%, with traffic (n = 532/61%) and falls (n = 233/27%) as the most common mechanisms. Eight patients (1%) died within 30 days of hospital admission. Fifteen per cent (n = 128) were severely injured. Among the patients transferred from another hospital, 46% (n = 24) had severe injuries. Helicopter Emergency Medical Services (HEMS) were more used in younger age groups and in patients more severely injured. CONCLUSIONS: In a developed healthcare system, the number of potentially severely injured children is small and with very few deaths following trauma. Transport and falls represent the most common causes of injury throughout all age groups, though with a tendency towards more transport-related injuries with increasing age. In-hospital trauma care is characterized by a low threshold for a multidisciplinary reception, low use of intensive care and need for emergency surgical procedures, though with increased need in the older children.

Precision of field triage in patients brought to a trauma centre after introducing trauma team activation guidelines.

BACKGROUND: Field triage is important for regional trauma systems providing high sensitivity to avoid that severely injured are deprived access to trauma team resuscitation (undertriage), yet high specificity to avoid resource over-utilization (overtriage). Previous informal trauma team activation (TTA) at Ulleval University Hospital (UUH) caused imprecise triage. We have analyzed triage precision after introduction of TTA guidelines. METHODS: Retrospective analysis of 7 years (2001-07) of prospectively collected trauma registry data for all patients with TTA or severe injury, defined as at least one of the following: Injury Severity Score (ISS) > 15, proximal penetrating injury, admitted ICU > 2 days, transferred intubated to another hospital within 2 days, dead from trauma within 30 days. Interhospital transfers to UUH and patients admitted by non-healthcare personnel were excluded. Overtriage is the fraction of TTA where patients are not severely injured (1-positive predictive value); undertriage is the fraction of severely injured admitted without TTA (1-sensitivity). RESULTS: Of the 4,659 patients included in the study, 2,221 (48%) were severely injured. TTA occurred 4,440 times, only 2,002 of which for severely injured (overtriage 55%). Overall undertriage was 10%. Mechanism of injury was TTA criterion in 1,508 cases (34%), of which only 392 were severely injured (overtriage 74%). Paramedic-manned prehospital services provided 66% overtriage and 17% undertriage, anaesthetist-manned services 35% overtriage and 2% undertriage. Falls, high age and admittance by paramedics were significantly associated with undertriage. A Triage-Revised Trauma Score (RTS) < 12 in the emergency department reduced the risk for undertriage compared to RTS = 12 (normal value). Field RTS was documented by anaesthetists in 64% of the patients compared to 33% among paramedics.Patients subject to undertriage had an ISS-adjusted Odds Ratio for 30-day mortality of 2.34 (95% CI 1.6-3.4, p < 0.001) compared to those correctly triaged to TTA. CONCLUSION: Triage precision had not improved after TTA guideline introduction. Anaesthetists perform precise trauma triage, whereas paramedics have potential for improvement. Skewed mission profiles makes comparison of differences in triage precision difficult, but criteria or the use of them may contribute. Massive undertriage among paramedics is of grave concern as patients exposed to undertriage had increased risk of dying.