Tag Archives: HEMS


Pre-hospital physician triage

A Swiss study examined the on site triage decision making of pre-hospital emergency physicians. Dispatch of the physicians was coordinated by trained nurses or paramedics.

OBJECTIVE: Accurate identification of major trauma patients in the prehospital setting positively affects survival and resource utilization. Triage algorithms using predictive criteria of injury severity have been identified in paramedic-based prehospital systems. Our rescue system is based on prehospital paramedics and emergency physicians. The aim of this study was to evaluate the accuracy of the prehospital triage performed by physicians and to identify the predictive factors leading to errors of triage.

METHODS: Retrospective study of trauma patients triaged by physicians. Prehospital triage was analyzed using criteria defining major trauma victims (MTVs, Injury Severity Score >15, admission to ICU, need for immediate surgery and death within 48 h). Adequate triage was defined as MTVs oriented to the trauma centre or non-MTV (NMTV) oriented to regional hospitals.

RESULTS: One thousand six hundred and eighti-five patients (blunt trauma 96%) were included (558 MTV and 1127 NMTV). Triage was adequate in 1455 patients (86.4%). Overtriage occurred in 171 cases (10.1%) and undertriage in 59 cases (3.5%). Sensitivity and specificity was 90 and 85%, respectively, whereas positive predictive value and negative predictive value were 75 and 94%, respectively. Using logistic regression analysis, significant (P<0.05) predictors of undertriage were head or thorax injuries (odds ratio >2.5). Predictors of overtriage were paediatric age group, pedestrian or 2 wheel-vehicle road traffic accidents (odds ratio >2.0).

CONCLUSION: Physicians using clinical judgement provide effective prehospital triage of trauma patients. Only a few factors predicting errors in triage process were identified in this study.

Accuracy of prehospital triage of trauma patients by emergency physicians: a retrospective study in western Switzerland
Eur J Emerg Med. 2011 Apr;18(2):86-93

Performance measures for HEMS services

A recent study highlights the need for uniform standards of outcome data collection in Helicopter Emergency Medical Services (HEMS) in Great Britain and aero-medical retrieval services in Australia. Suggested patient outcome measurements by Britsh and Australian air medical respondents to the survey included:

  1. Mortality versus TRISS predicted mortality
  2. APACHE/ TRISS predicted mortality versus actual mortality.
  3. Use of national audit tools (eg, TARN)
  4. Nationally agreed Key Performance Indicators (KPIs)
  5. Clinical outcomes benchmarked against other services
  6. In-mission clinical indicators (eg, unanticipated procedures, adverse events)
  7. Physiological scoring linked to outcome measures
  8. ISS versus survival/disability
  9. KPIs from a national body. Mortality in isolation is not a useful marker of quality
  10. Clinical KPIs provided there is a reliable method of data collection
  11. Long-term outcome
  12. Interventions performed by doctors that contribute to patient mortality/morbidity.

Background Performance outcome measures are an essential component of health service improvement. Whereas hospital critical care services have established performance measures, prehospital care services have less well-established outcome measures and this has been identified as a key issue for development. Individual studies examining long-term survival and functional outcome measures have previously been used to evaluate prehospital care delivery. There is no set of standardised patient outcome measures for Helicopter Emergency Medical Services (HEMS) in the UK or Air Medical Services (AMS) in Australia. The aim of this study is to document the patient outcome measures currently in use within British HEMS and Australian AMS.

Methods This is an observational study analysing point prevalence of practice as of November 2009. A structured questionnaire was designed to assess the method of routine patient follow-up, and the timing and nature of applied patient outcome measures.

Results Full responses were received from 17/21 (81%) British services and 6/7 (86%) Australian services. The overall response rate was 82%.

Conclusions HEMS in Britain and Australian aeromedical retrieval services do not have uniform patient outcome measures. Services tend not to follow-up patients beyond 24 h post transfer. Patient outcome data are rarely presented to an external organisation and there is no formal data comparison between surveyed services. Services are not satisfied that the data currently being collected reflects the quality of their service.

Performance measurement in British Helicopter Emergency Medical Services and Australian Air Medical Services
Emerg Med J. 2011 Feb 3. [Epub ahead of print]

Delayed door-to-balloon even with helicopters

For a whole bunch of reasons, patients with ST-elevation myocardial infarction who undergo interhospital transfer for primary percutaneous coronary intervention may not meet the required 90 minute door-to-balloon time. In a new study of patients transferred by helicopter, only 3% of STEMI patients transferred for reperfusion met the 90-minute goal. Should this result in an increase in the use of fibrinolysis at non–percutaneous coronary intervention hospitals?

Opportunity for gratuitous helicopter shot never knowingly declined

STUDY OBJECTIVE: Early reperfusion portends better outcomes for ST-segment elevation myocardial infarction (STEMI) patients. This investigation estimates the proportions of STEMI patients transported by a hospital-based helicopter emergency medical services (EMS) system who meet the goals of 90-minute door-to-balloon time for percutaneous coronary intervention or 30-minute door-to-needle time for fibrinolysis.

METHODS: This was a multicenter, retrospective chart review of STEMI patients flown by a hospital-based helicopter service in 2007. Included patients were transferred from an emergency department (ED) to a cardiac catheterization laboratory for primary or rescue percutaneous coronary intervention. Out-of-hospital, ED, and inpatient records were reviewed to determine door-to-balloon time and door-to-needle time. Data were abstracted with a priori definitions and criteria.

RESULTS: There were 179 subjects from 16 referring and 6 receiving hospitals. Mean age was 58 years, 68% were men, and 86% were white. One hundred forty subjects were transferred for primary percutaneous coronary intervention, of whom 29 had no intervention during catheterization. For subjects with intervention, door-to-balloon time exceeded 90 minutes in 107 of 111 cases (97%). Median door-to-balloon time was 131 minutes (interquartile range 114 to 158 minutes). Thirty-nine subjects (21%) received fibrinolytics before transfer, and 19 of 39 (49%) received fibrinolytics within 30 minutes. Median door-to-needle time was 31 minutes (interquartile range 23 to 45 minutes).

CONCLUSION: In this study, STEMI patients presenting to non-percutaneous coronary intervention facilities who are transferred to a percutaneous coronary intervention-capable hospital by helicopter EMS do not commonly receive fibrinolysis and rarely achieve percutaneous coronary intervention within 90 minutes. In similar settings, primary fibrinolysis should be considered while strategies to reduce the time required for subsequent interventional care are explored.

Reperfusion Is Delayed Beyond Guideline Recommendations in Patients Requiring Interhospital Helicopter Transfer for Treatment of ST-segment Elevation Myocardial Infarction.
Ann Emerg Med. 2011 Mar;57(3):213-220

Pre-hospital / HEMS podcast

I was lucky enough to be interviewed by the amazing Scott Weingart, an emergency medicine intensivist who runs the spectacular EMcrit podcast. We covered some stuff on pre-hospital airway management, physicians in pre-hospital care, and I had a rant about ‘scoop and run’ versus ‘stay and play’. Worryingly, Scott is keeping back some audio footage for a later podcast, probably containing an even bigger rant about things like ATLS.

Click the image to be taken to the EMcrit site where you can listen to the podcast.

Helicopters between hospitals

More National Trauma Databank analysis coming out in favour of helicopter transport: this time looking at interhospital transfer:

Background: Helicopter transport (HT) is frequently used for interfacility transfer of injured patients to a trauma center. The benefits of HT over ground transport (GT) in this setting are unclear. By using a national sample, the objective of this study was to assess whether HT impacted outcomes following interfacility transfer of trauma patients.

Methods: Patients transferred by HT or GT in 2007 were identified using the National Trauma Databank (version 8). Injury severity, resource utilization, and survival to discharge were compared. Stepwise logistic regression was used to determine whether transport modality was a predictor of survival after adjusting for covariates. Regression analysis was repeated in subgroups with Injury Severity Score (ISS) ≤15 and ISS >15.

Results: There were 74,779 patients transported by helicopter (20%) or ground (80%). Mean ISS was higher in patients transported by helicopter (17 ± 11 vs. 12 ± 9; p < 0.01) as was the proportion with ISS >15 (49% vs. 28%; odds ratio [OR], 2.53; 95% confidence interval [CI], 2.43-2.63). Patients transported by helicopter had higher rates of intensive care unit admission (54% vs. 29%; OR, 2.86; 95% CI, 2.75-2.96), had shorter transport time (61 ± 55 minutes vs. 98 ± 71 minutes; p < 0.01), and had shorter overall prehospital time (135 ± 86 minutes vs. 202 ± 132 minutes; p < 0.01). HT was not a predictor of survival overall or in patients with ISS ≤15. In patients with ISS >15, HT was a predictor of survival (OR, 1.09; 95% CI, 1.02-1.17; p = 0.01).

Conclusions: Patients transported by helicopter were more severely injured and required more hospital resources than patients transported by ground. HT offered shorter transport and overall prehospital times. For patients with ISS >15, HT was a predictor of survival. These findings should be considered when developing interfacility transfer policies for patients with severe injuries.

Helicopters Improve Survival in Seriously Injured Patients Requiring Interfacility Transfer for Definitive Care
J Trauma. 2011 Feb;70(2):310-4.

Helicopters and trauma: systematic review

In the midst of reconfiguring its trauma systems, the United Kingdom’s National Health Service needed to evaluate the cost effectiveness of helicopter emergency medical services (HEMS). A systematic literature review was undertaken of all population-based studies evaluating the impact on mortality of helicopter transfer of trauma patients from the scene of injury. The authors also attempted to analyse whether it is the helicopter as a transport platform or the standard of the emergency medical service that accounts for any differences seen.

A search of the literature revealed 23 eligible studies. 14 of these studies demonstrated a significant improvement in trauma patient mortality when transported by helicopter from the scene. 5 of the 23 studies were of level II evidence with the remainder being of level III evidence.

Only one eligible study assessed HEMS in the UK. The other papers reported data from the USA, Italy, Australia, the Netherlands, Germany and South Africa.

The majority of studies show a mortality benefit with HEMS: fourteen studies reported results that demonstrated a significant mortality rate improvement with HEMS, four reported data that did not reach significance and five did not report whether results reached significance.

The authors suggest this variation may be a result of any of the following factors, and provide a thorough discussion of the literature pertaining to each of them:

  1. Transport of a physician to the scene
  2. Transport of advanced airway skills to the scene
  3. Transporting a team experienced in managing trauma patients
  4. Triage to the definitive treatment facility

The full text of the review is available at the link below.

Is it the H or the EMS in HEMS that has an impact on trauma patient mortality? A systematic review of the evidence
EMJ 2010;27(9):692-701 (Free Full Text)

HEMS transport may be predictor of survival

Helicopters are controversial in EMS circles, particularly in the United States, which seems to have a high number of Helicopter Emergency Medical Services (HEMS) crashes. Although this may in part be a reflection of a large increase in HEMS missions, and the factors contributing to crash fatalities have been studied, it makes sense to limit HEMS missions to those that are likely to make a difference to the patient. Advantages of HEMS services may include the ability to deliver a patient more rapidly to the most appropriate facility, as well as being able to convey a highly skilled team more rapidly to the scene.

Analysis of patients from the National Trauma Databank identified 258,387 subjects transported by either helicopter (HT) (16%) or ground ambulance (GT) (84%). HT subjects were younger (36 years ± 19 years vs. 42 years ± 22 years; p < 0.01), more likely to be male (70% vs. 65%; < 0.01), and more likely to have a blunt mechanism (93% vs. 88%; < 0.01) when compared with GT subjects.

For every dead-on-arrival (DOA) subject in the HT group, there were 498 survivors compared with 395 survivors for every DOA subject in the GT group. When comparing indicators of injury severity, patients transported by helicopter were more severely injured (mean ISS and percentage with ISS > 15), were more likely to have a severe head injury, and were more likely to have documented hypotension or abnormal respiratory when compared with those transported by ground ambulance. Furthermore, HT subjects also had longer length of stay, higher rates for ICU admission, and mechanical ventilation, as well as an increased requirement for emergent surgical intervention.

interestingly, this study shows that <15% of HT patients nationally are discharged within 24 hours. This is much lower than the 24.1% reported previously, suggesting that the degree of over-triage may not be as significant on the national level as reported in smaller studies.

Overall survival was lower in HT subjects versus GT subjects on univariate analysis (92.5% vs. 95.6%; < 0.01). Stepwise univariate analysis identified all covariates for inclusion in the regression model. HT became an independent predictor of survival when compared with GT after adjustment for covariates (OR, 1.22; 95% CI, 1.18– 1.27; < 0.01).

Helicopters and the Civilian Trauma System: National Utilization Patterns Demonstrate Improved Outcomes After Traumatic Injury
J Trauma. 2010 Nov;69(5):1030-4

National Transportation Safety Board HEMS data

Scene times for rural retrieval in Scotland

The Emergency Medical Retrieval Service (EMRS) provides an aeromedical retrieval service to remote and rural communities in Scotland. They examined 300 retrievals over a five year period and showed a correlation between amount of critical care interventions required and total time on scene (defined as the total length of time between the aircraft landing and taking off from the scene, this includes access to patient, transfer to the helicopter and packaging for flight departure). Median scene time for both medical and trauma patients was 60 minutes.

Map of the area currently covered by the EMRS, showing medical facilities served

The authors remind us that critical care secondary retrieval from rural healthcare facilities has many similarities to prehospital care (primary retrieval), and therefore consideration of scene times is of interest.

On-scene times and critical care interventions for an aeromedical retrieval service
Emerg Med J. 2010 Aug 19. [Epub ahead of print]

Ketamine for HEMS intubation in Canada

Ketamine was used by clinical staff from the The Shock Trauma Air Rescue Society (STARS) in Alberta to facilitate intubation in both the pre-hospital & in-hospital setting (with a neuromuscular blocker in only three quarters of cases). Changes in vital signs were small despite the severity of illness in the study population.

A prospective review of the use of ketamine to facilitate endotracheal intubation in the helicopter emergency medical services (HEMS) setting
Emerg Med J. 2010 Oct 6. [Epub ahead of print]

Pre-hospital RSI

Physicians from HEMS London document their experience of 400 pre-hospital rapid sequence induction / intubations. Their data are consistent with the experience of other similar services and with the emergency airway management literature in general:

  • Failure to intubate is rare
  • Removing cricoid pressure often improves the view
  • A BURP manoeuvre can improve the view and facilitate intubation, but bimanual laryngoscopy / external laryngeal manipulation is better
  • Having an SOP optimises first-pass success rate

Cricoid pressure and laryngeal manipulation in 402 pre-hospital emergency anaesthetics: Essential safety measure or a hindrance to rapid safe intubation?
Resuscitation 2010(81):810–816