Prehospital medications: thrombolytic use in cardiac events

The 2013 ACCF/AHA guidelines for ST-elevation myocardial infarction (STEMI) transitioned “door to balloon time” of ≤90 minutes to the more rigorous “first medical contact to device time” of ≤90 minutes [4]. First medical contact is typically defined as the first EMS provider on scene who can perform a 12-lead ECG, though some consider it to be the dispatcher answering the 9-1-1 call. It also describes the ability to reduce delay from symptom onset to treatment by administering prehospital fibrinolytics either by an EMS unit with a physician on board or in direct contact with a hospital-based physician. Multiple randomized controlled trials have demonstrated the safety and feasibility of prehospital fibrinolytics [5–8]. The majority of these studies were performed in the UK or Europe and the use of thrombolytics in the prehospital setting for STEMI patients in the US is rare.

Many EMS systems use telemedicine to obtain a 12-lead ECG in the field and transmit, usually by cellular phone to fax, to a receiving hospital in an effort to prenotify the hospital and activate the cardiac catheterization lab. Mavrogeni et al. reported the success of using telemedicine (remote transmission of ECGs) to supervise the administration of thrombolytics in six rural medical centers in Greece [9]. Björklund et al. showed that with the assistance of telemedicine (ECG transmission to hospital CCU and telephone review of indications with cardiologist), they were able to administer prehospital thrombolytic therapy and in doing so not only reduced time delay of treatment by approximately 1 hour but also reduced 1-year mortality by 30% compared to those STEMI patients who received in-hospital thrombolytics [10]. Similarly in Scotland, Pedley et al. were able to use telemedicine equipment (mobile telemetry link with radio to emergency physicians) to assist in making decisions to administer prehospital thrombolytics to STEMI patients, and decrease time delay of treatment by 73 minutes in comparison to patients who received in-hospital thrombolytics [11].

Telestroke

Reports from the TeleBAT (Telemedicine for the Brain Attack Team) program at the University of Maryland in 2000 and 2004 demonstrated the feasibility of performing stroke evaluations by remote neurologists using cellular narrow bandwidth videoconferencing (one image every 2 seconds) in ambulances [12,13]. A more recent pilot study has looked at the feasibility of prehospital transmission of real-time streaming video, vital data, and still picture transmission facilitating neurological evaluation. Initial conclusions have established the feasibility of teleconsultation while raising concerns over delays in care with patients managed using this system [14]. An article by Liman et al. also raised concerns over the technical implementation and clinical usability of a typical telestroke “evaluation in the ambulance” system [15]. A recent German study has shown that EMS stroke response with a computed tomography (CT) scanner equipped ambulance with an onboard neurologist and teleradiological support can potentially shorten times to stroke treatment with thrombolytics [16]. It remains to be seen how the latest generation of telemedicine systems specifically designed for use in the ambulance setting, such as LifeBot DREAMStm [17] and e-Bridge from General Devices[18], perform in facilitating examinations while preserving or enhancing timeliness to indicated thrombolytic care. Additionally, in the absence of a CT scanner in the field, the question arises whether telemedicine examinations by emergency physicians or neurologists are superior to examinations and decision making over stroke center referrals by EMS personnel with training in stroke assessment.

Refusal of medical care/treat and release

Throughout the United States, it is common practice to have prehospital providers contact direct medical oversight physicians for further direction in situations where patients refuse medical care or would like to be released after having had some form of medical treatment in the field. Studies have shown that when a patient was able to speak to a physician, there was a higher likelihood (35%, versus 3% when the patient spoke only to the EMS provider) that the patient would ultimately be transported to a hospital [19,20]. Other studies focused on the physician’s assertiveness and showed that if the physician was concerned with the patient’s clinical status, he or she was likely to be more assertive when talking to the patient, which would ultimately improve the patient transport rate [21]. In the manner of Cukor et al., the addition of video promises to enhance these interactions by creating a “social presence” in which the patient and provider can better discuss these complex issues [22].

Patient transport decision making

Air medical transport is an integral component of the EMS system, allowing patients to be moved quickly to a suitable facility for appropriate medical care. Its introduction into the civilian world began in the 1970s after military air medical evacuation experiences during the Vietnam War had shown the effectiveness of helicopters for removing wounded soldiers from the battlefield. There is growing controversy about the overutilization and cost-effectiveness of air transport over ground transport [23]. A retrospective analysis by Shatney et al. of 947 trauma patients transported by air in an urban setting showed that although transport time was decreased when using a helicopter, only 22.8% of the population benefitted from the quicker transport [24]. Similarly, Bledsoe et al. performed a metaanalysis of 37,350 trauma patients transported by helicopter from the scene of injury. They measured the severity of the injuries using Injury Severity Score, Trauma Score, and Trauma Score Injury Severity Score and found the majority of the patients had minor or non-life threatening injuries (60.0%, 61.4%, and 69.3%, respectively) [25]. In order to determine if the routine use of helicopter EMS is cost-effective, Delgado et al. developed a decision-analytic Markov model to compare the costs and outcomes of helicopter versus ground EMS. Based on the model assumptions, the study showed that helicopter transport is cost-effective only if it reduces the relative risk of death in seriously injured trauma patients by at least 15%. This implies that the best way to increase cost-effectiveness of helicopter transport would be to reduce the overtriaging of minor injuries to helicopter EMS [26].

Telemedicine should have a role in reducing overutilization, in concert with stricter guidelines for utilization. In Taiwan, Tsai et al. performed a prospective cohort study showing that when using video telemedicine to screen the patient, there was a 36.2% reduction in the use of air transport, resulting in a total annual savings of US $448,986 [27]. Similarly, in a study of interhospital burn transfers with relevance to a prehospital setting, Saffle et al. completed a review analyzing whether the use of telemedicine in evaluating burn patients would have altered the need for air, ground, or no transport from a community hospital. Of the 225 burn patients who were air transported, only 60% were deemed necessary for air transport, while 18% could have been treated at the outlying facility. In addition, 34% of the patients had air transport charges that exceeded their total charges for hospitalization [28]. Telemedicine appears to be effective in reducing the overutilization of air transport and by doing so, increasing its cost-effectiveness and helping reduce unnecessary health care costs or risks to air medical crews.