Evidence map›Paper›PMID 40186215›Full record

ArticleScandinavian journal of trauma, resuscitation and emergency medicine2025

The impact of concurrency conflicts on optimal location of air ambulance bases in Norway.

Jo Røislien, Pieter L van den Berg, J Theresia van Essen, Oddvar Uleberg, Caroline Jagtenberg

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Article in Scandinavian journal of trauma, resuscitation and emergency medicine, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.

0numbers the graph read from it
0cells of the map it votes in
5citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

5 citing papers in PubMed.

  1. Observational
  2. Article
  3. Article
  4. Selection of helicopter bases and transport modes to minimize pre-hospital times in Iceland.Scandinavian journal of trauma, resuscitation and emergency medicine · 2025
    Article
  5. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Jo RøislienDepartment of Research, The Norwegian Air Ambulance Foundation, Oslo, Norway. jo.roislien@norskluftambulanse.no.
Pieter L van den BergDepartment of Technology and Operations Management, Rotterdam School of Management, Erasmus University, Rotterdam, the Netherlands.
J Theresia van EssenDelft Institute of Applied Mathematics, Delft University of Technology, Delft, the Netherlands.
Oddvar UlebergDepartment of Research, The Norwegian Air Ambulance Foundation, Oslo, Norway.
Caroline JagtenbergDepartment of Operations Analytics, School of Business and Economics, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundHelicopter emergency medical services (HEMS) are important in many health care systems. In order to best utilize this expensive healthcare service, the location of HEMS bases is key. Concurrency conflicts is a prominent deviation for not completing missions, yet is often overlooked in mathematical modelling. The aim of the present study was to calculate optimal air ambulance base locations when accounting for the potential unavailability of helicopters due to concurrency conflicts.

methodsWe used incident data for Norway from 2015. Optimal helicopter base locations were estimated using the Maximum Expected Covering Location Problem (MEXCLP) optimization model, allowing for estimation of the impact of concurrency conflicts by introducing a busy fraction parameter in the model. We explored busy fractions of 0, 0.10, 0.20 and 0.30, representing helicopters on the HEMS bases being busy 0, 10, 20 and 30% of the time, respectively. Both greenfield scenarios and simulations conditioned on the existing base structure were explored.

resultsThe 428 municipalities had a median (5-95 percentile) of 10 (2-38) incidents. Assuming a helicopter is always available, the existing bases cover an estimated 73.6% of the incidents within 30 min. Increasing the busy fraction in the calculations resulted in a significant decrease in estimated coverage. Re-arranging the currently available 14 helicopters in a greenfield analysis increases coverage to 91.9%. Increasing the busy fraction in the models, the mathematically optimal solutions put increasingly more emphasis on the more densely populated greater Oslo area, removing helicopters from northern Norway and the coastal areas, where population is more spread.

conclusionThe busy fraction significantly impacts the optimal location of air ambulance bases, with higher busy fractions resulting in more helicopters being placed in the more densely populated areas where demand is higher. However, the actual busy fractions reported in the Norwegian HEMS system seem to be of a magnitude small enough to have little impact on the optimal location of HEMS bases and helicopters. To determine the impact of adjusting for non-homogeneous busy fractions across the country more refined busy fraction models are needed.

Indexed as

Air AmbulancesEmergency Medical ServicesHumansModels, TheoreticalNorwayAir ambulanceBusy fractionConcurrency conflictsCoverageFacility location problemHEMSIncidentsMCLPMEXCLP

Identifiers

PMID40186215
PMCPMC11969883

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.