Protocol of the DENIM study: a Delphi-procedure on the identification of trauma patients in need of care by physician-staffed Mobile Medical Teams in the Netherlands

In The Netherlands standard prehospital trauma care is provided by emergency medical services (EMS). All EMS care providers are highly trained and registered nurses with certification in either anaesthesia, intensive care, cardiac care or emergency care and additional training in prehospital trauma life support [1,2]. In order to enhance prehospital care for the severely injured patient in The Netherlands, the Mobile Medical Team (MMT) was introduced in 1995 and was extended by night flight coverage in 2006 [3]. Nowadays, The Netherlands is covered by four MMTs that are stand-by 24/7 and have the availability of either helicopter or road ambulance transportation. A MMT rapidly delivers advanced trauma life support to the trauma patient in the out-of hospital setting. A Dutch MMT consists of either a specialized anaesthesiologist or trauma surgeon and a specialized trauma nurse with at least five years of working experience in the Emergency Room or at the EMS. The MMT supplements the prehospital trauma life support performed by the EMS with advanced trauma care according to, but also beyond Advanced Trauma Life Support. Procedures performed are, amongst others, rapid sequence intubation, advanced pain management, the administration of inotropes, vasopressors and other medication. Moreover, a MMT can perform invasive surgical interventions such as surgical airway, intercostal drainage, splinting, thoracotomy and advanced haemorrhage control. The primary objective of a MMT is swift transport of advanced trauma care to the injured trauma patient in order to perform early life saving interventions. MMTs are mainly transported by helicopter (69%), but also by road [4]. In most of the cases the MMT physician accompanies the patient to the hospital in the EMS road ambulance and in 5-20% of the cases the trauma patient is transported by the MMT in the helicopter. At the scene, the MMT physician is responsible for the prehospital logistical process. The MMT physician decides on the type and order of treatment as well as to which hospital the trauma patient should be transported, based on their knowledge and experience as specialists in trauma care augmented by their frequent exposure to specific situations and patient conditions. Though MMT care has been implemented for several years now, deployment of the teams could be more efficient. A study by Giannakopoulos et al. showed an overtriage rate of 26% for one of the Dutch MMT’s [4]. Another study in the same cohort of dispatches showed that 21% of all cancellations of this MMT concerned major trauma patients [5]. This may be interpreted as undertriage, as this patient category is thought to benefit most by the prehospital assistance of the MMT. Differences in interpretation and application of the MMT dispatch and cancellation criteria by emergency medical personnel may be an underlying cause. Several reasons for this phenomenon can be listed such as regional differences in working culture (and familiarity with MMT care), professional autonomy of care takers in all involved disciplines (adherence to guidelines) and a difference in trauma-related knowledge and/or exposure. Current dispatch criteria are active since June 2013 and based on two national ambulance protocols and a study by Ringburg et al. reviewing dispatch criteria [6,7]. Key topics of the current criteria are shown in Table 1. Based on these assumptions, the nature of the incident, location and time of transport appear to be of secondary importance. In the available literature, many articles describe research in the U.S. paramedic based EMS-setting or in the German physician based prehospital system-setting. The findings of this research cannot simply be compared or extrapolated to the Dutch hybrid (EMS and MMT) prehospital system [4,6]. Current dispatch criteria are mainly based on level 4 evidence (expert opinion and experience) [8], with the exception of loss of consciousness which has been proven a reliable and validated parameter for Helicopter Emergency Medical Services (HEMS) dispatch [6]. In the event of a severe trauma, emergency operators in the dispatch centre deploy the MMT simultaneously with the EMS ambulance crew (dispatch sequence is displayed in Figure 1). The decision for dispatch is done based on information handed to the operator by a layperson. Because this information can be incomplete or incorrect the dispatch centres handles a low activation threshold for dispatch to minimise undertriage. The National Institute for Public Health and the Environment (RIVM) report on distinct differences in the absolute numbers of dispatches between the four Dutch MMTs [9]. Several possible reasons for the occurrence of these differences are suggested. Firstly, the RIVM report shows that the greater the geographical distance between the dispatch centre and the MMT-base, the less likely emergency operators are to deploy the MMT. Organisational and management factors such as limited or insufficient protocol implementation in the dispatch centre may be of influence. Finally, sociocultural aspects may play a role; including inexperience, biased working culture, individual attitudes, poor communication and levels of training of both ambulance and MMT personnel [9]. The DENIM study (‘DELphi studie in Nederland naar de Inzet van het MMT’ Delphi study in the Netherlands on the dispatch of the Mobile Medical Team) aims at reaching consensus in expert opinion on the question; ‘which trauma patient deserves the advanced care provided by a MMT?’. This consensus can then be used to invigorate MMT dispatch criteria in the future. The objective of this paper is to describe the design of the DENIM study.