The effect of medical care by a helicopter trauma team on the probability of survival and the quality of life of hospitalised victims

doi:10.1016/S0001-4575(00)00023-3

Accident Analysis & Prevention

Volume 33, Issue 1, January 2001, Pages 129-138

https://doi.org/10.1016/S0001-4575(00)00023-3 Get rights and content

Abstract

In 1995, an experiment was started to give extra medical help by helicopter to patients who needed emergency treatment. The aim of the experiment was not to reduce the transportation time to the hospital, but to bring specialised medical care directly to patients as soon as possible. An evaluation study was carried out to assess the effect of the treatment given by the Helicopter Trauma Team (HTT) on survival and quality of life. The study focused on hospitalised patients suffering from polytrauma. A direct comparison between an experimental and control group was not possible, because the HTT group consisted of more severely injured patients. A refined severity index was constructed on the basis of the Revised Trauma Scale (RTS) and the Injury Severity Scale (ISS) and their sub-scores. Using this index, it was possible to make a clear distinction between three groups of patients, i.e. those with a high probability of survival (with or without special medical treatment), those with a very low probability of survival and the patients in between. It was shown that the HTT-treatment was effective. The survival rate increased for patients in the ‘in between’ group, but not for patients with a low probability of survival. There was no difference in the quality of life of patients from the HTT and non-HTT groups 15 months after the accident. These findings refute the hypothesis that only the most severely injured patients with a low quality of life profit from HTT-treatment.

Introduction

The Royal Dutch Touring Organisation (ANWB) and the University Hospital in Amsterdam (AZVU) initiated an experiment in which medical help by helicopter was given to patients needing emergency care. The experiment started on 1 May 1995. Medical assistance was given to polytrauma patients (PTP’s): accident victims with various injuries, which alone or in combination with other injuries, could be life-threatening. In many other countries, helicopter assistance is used to reduce the delay before arrival at the hospital. The major aim of the Dutch project is to bring medical care to the scene of the accident as soon as possible. The Helicopter Trauma Team (HTT) consisted of a doctor, a nurse and a pilot. This team was constantly available during daylight conditions. It operated in an area with a radius of 50 km around the AZVU-hospital. The helicopter was stationed on the roof of the hospital. In all cases an ambulance team was also sent out. After medical treatment, most patients were brought to hospital by ambulance, sometimes assisted by the HTT doctor. The helicopter was used to transport the patient only on rare occasions.

The SWOV Institute for Road Safety Research and the Centre for Health Policy and Law (CGBR) of the Erasmus University, Rotterdam were commissioned by the National Health Insurance Council to investigate the effectiveness of HTT’s. Also examined was the effectiveness of these activities in relation to the additional costs involved, when compared with the traditional assistance provided by ambulance. Finally considered were the conclusions to be drawn from this study in regard to the possible application of helicopter assistance throughout the Netherlands (De Charro and Oppe, 1998). In this paper only the effectiveness of HTT’s on survival and quality of life will be reported.

Section snippets

Objective of the study

The investigation into effectiveness focused on two aspects of the emergency assistance: the mortality (death rate) of the group as a whole, and the quality of life of the group of victims who survived their injuries. The investigation into the cost effectiveness of the helicopter assistance used information generated from the experiment to calculate the implications of offering helicopter assistance throughout the Netherlands. More specifically, this involved a calculation of the costs for

Previous experiences

The earliest experiences of providing air transport for emergency care were gained during wartime. During the Franco–German War in the 19th century, balloons were used to transport wounded soldiers from the battlefield to hospital. In the First and Second World War, transport of wounded soldiers by air was used on a large scale. During the Korean War, helicopters were used for the first time to transport wounded soldiers. Helicopters were also widely used during the Vietnam War.

In general,

Data related to polytrauma patients

For the purposes of this study, information was gathered regarding PTP’s who had been victims of accidents between 1 May 1995 and 31 December 1996. Data was collected from 11 Central Post Ambulance care (CPA) institutions, the Ambulance teams in the experimental region, the HTT and eight specialised (primarily academic) hospitals in the region. The standard forms, used at the intake of patients proved useful.

For each seriously injured patient, pre-clinical information was collected by the

The effect of HTT-treatment on mortality

A direct comparison of the death rate for patients treated and not treated by the HTT was not possible, because of the selective recruitment of patients: the helicopter assistance was primarily focused on the treatment of the most severely injured patients. Therefore the prior odds for survival in the HTT group were considerably lower than in the non-HTT group. This situation is an example of the so-called ‘Simpson paradox’, i.e. if the probability of survival, given a certain level of

Quality of life

From the 1026 patients who were included in this study, 240 died. Fifty one patients could not be approached for a quality of life interview for other reasons. From the remaining 735 patients, 303 could not be interviewed. The reasons were as follows: they could not be traced or could not be traced in time (168); they refused informed consent (96); they lived abroad or did not speak Dutch (25); they sustained injuries such as neurological impairment or they were mentally disabled (14). Quality

Conclusions and recommendations

The major conclusion of the study was that HTT-treatment was effective in saving lives of seriously injured victims from accidents that were taken to hospital. The effect was found almost completely in the subgroup of victims from road accidents. The patients treated effectively were not among the most seriously injured, but those with an intermediate probability of survival. The quality of life of the patients 15 months after the accident took place, although considerably reduced for PTP’s,

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Approximately one-third of all severely injured patients in the Netherlands are not initially treated at an MTC. Special attention needs to be directed to identifying patient groups with a high risk of undertriage. Furthermore, resources to overcome longer transport times to an MTC, including the availability of ambulance and helicopter services, may improve direct MTC care and result in a decrease in the variation of the undertriage of severely injured patients to MTCs among the Dutch trauma networks. Furthermore, attention needs to be directed to improving primary triage guidelines and instituting uniform interfacility transfer agreements.
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Five hundred and forty-eight articles were screened, and 16 were included. Only one study compared the performance of the different models of dispatch. A non-statistically significant reduction in the length of time for HEMS resources to reach incident scenes of 4 min was found when primary dispatch protocols were utilised compared to requests from EMS personnel at scene. No effect on mortality; severity of injury or proportion of patients admitted to intensive care was observed.
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This review identifies a lack of evidence supporting the role of primary dispatch models in targeting the deployment of Enhanced Care Teams to patients with severe injuries. It is therefore not possible to identify a model for ECT dispatch within pre-hospital systems that optimises resource utilisation.
Further studies are required to assess the efficiency of systems utilised at each stage of the process used to dispatch Enhanced Care Team resources to incidents within regionalised pre-hospital trauma systems.
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The effect of medical care by a helicopter trauma team on the probability of survival and the quality of life of hospitalised victims

Abstract

Introduction

Section snippets

Objective of the study

Previous experiences

Data related to polytrauma patients

The effect of HTT-treatment on mortality

Quality of life

Conclusions and recommendations

Annals of Emergency Medicine

Accident Analysis and Prevention

The impact of a rotorcraft aeromedical emergency care services on trauma mortality

Journal of the American Medical Association

The impact of advanced pre-hospital emergency care on mortality of severely brain-injured patients

The Journal of Trauma

Evaluating trauma care: the TRISS method

The Journal of Trauma

Modeling valuations for EuroQol Health States

Medical Care