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Helicopter rescue operations involving winching of an emergency physician
Injury, Int. J. Care Injured 43 (2012) 1377–1380
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Helicopter rescue operations involving winching of an emergency physician M. Pasquier a,b,*, V. Geiser a, M. De Riedmatten b, P.N. Carron a a b
Emergency Service, University Hospital Center, Lausanne, Switzerland Air-Glaciers, Maison FXB du Sauvetage, Sion, Switzerland
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 22 June 2011
Objective: We sought to study the epidemiologic and medical aspects of alpine helicopter rescue operations involving the winching of an emergency physician to the victim. Methods: We retrospectively reviewed the medical and operational reports of a single helicopter-based emergency medical service. Data from 1 January 2003 to 31 December 2008 were analysed. Results: A total of 921 patients were identified, with a male:female ratio of 2:1. There were 56 (6%) patients aged 15 or under. The median time from emergency call to helicopter take-off was 7 min (IQR = 5–10 min). 840 (91%) patients suffered from trauma-related injuries, with falls from heights during sports activities the most frequent event. The most common injuries involved the legs (246 or 27%), head (175 or 19%), upper limbs (117 or 13%), spine (108 or 12%), and femur (66 or 7%). Only 81 (9%) victims suffered from a medical emergency, but these cases were, when compared to the trauma victims, significantly more severe according to the NACA index (p < 0.001). Overall, 246 (27%) patients had a severe injury or illness, namely, a potential or overt vital threat (NACA score between 4 and 6). A total of 478 (52%) patients required administration of major analgesics: fentanyl (443 patients or 48%), ketamine (42 patients or 5%) or morphine (7 patients or 1%). The mean dose of fentanyl was 188 micrograms (range 25–750, SD 127). Major medical interventions such as administration of vasoactive drugs, intravenous perfusions of more than 1000 ml of fluids, ventilation or intubation were performed on 39 (4%) patients. Conclusions: The severity of the patients’ injuries or illnesses along with the high proportion of medical procedures performed directly on-site validates emergency physician winching for advanced life support procedures and analgesia. ß 2011 Elsevier Ltd. All rights reserved.
Keywords: Air ambulance Aircraft Emergency medical services Mountaineering Rescue work Switzerland
Introduction The number of helicopter-based emergency medical services (HEMS) rescue operations for people involved in outdoor leisure activities has increased over the last few years.1 Helicopter rescues offer several advantages over ground transport, including the ability to perform air searches for lost victims, rapidly shuttle rescue personnel and equipment to the scene, deliver timely onsite advanced medical care decreasing both the number of rescuers required for ground evacuation and exposure to hazards associated with hostile environments, and reduce patient transport time to the hospital.2 On the other hand, HEMS operations have higher accident and fatality rates when compared to helicopter operations in other fields.3 The risk factors include night flight and poor weather, the latter being frequently the case during mountain rescues.4 Winching procedures account for a non-negligible
* Corresponding author at: Emergency Service, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland. Tel.: +41 79 556 34 22; fax: +41 21 314 08 71. E-mail address: [email protected] (M. Pasquier). 0020–1383/$ – see front matter ß 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2011.06.196
number of incidents during rescue missions,5 and therefore are not used by all HEMS and in all countries.6 Whereas the use of helicopters as a rapid means to reach victims and to bring them to a secure place is well-recognised, there are very few data available about the value of winching physicians to provide medical care for the victims directly on-site. We analysed the medical aspects of helicopter rescue operations involving winching of an emergency physician in a Swiss setting. Air-Glaciers’ helicopter-based emergency medical service Air-Glaciers (AG) is a commercial rescue company founded in 1965 based in the heart of the Alps in Sion, Switzerland. This helicopter-based emergency medical service covers a resident population of about 220,000, and grows significantly during the peak tourist seasons in winter and summer. AG intervenes at altitudes from 500 to over 4000 metres, with a time of flight from the base to the scene of generally less of 20 min. The base covers an operational area of 250 km2. About 1700 rescue flights are made each year, of which more than 90% are primary missions ranging from road traffic accidents to high altitude
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mountain rescues, whilst 10% are interhospital transfers. Most of the patients are admitted either to the local trauma and medical centre of Sion which has neurosurgery, cardiovascular surgery, intensive care and coronary angioplasty services, or to the nearby University Hospital of Lausanne. Operational aspects The AG’s base station can simultaneously deploy up to 5 helicopters equipped with medical staff during the peak tourist season. It is the only service operating in this geographical area, although helicopters from other companies can be engaged in a one-off basis for extraordinary circumstances. All rescue missions requiring a winch strategy also include a mountain guide with a paramedical training. Depending on the presumed severity of the medical situation, an emergency physician is winched either as a first course of action, or as recommended after the mountain guide’s initial evaluation of the situation. A spine board, a monitor/ defibrillator, an electric suction device and a medical bag with advanced life support material (intubation and resuscitation drugs) are taken on-site by the rescuers as needed. After immobilisation and stabilisation of the patient, extrication with the winch is followed by a short flight until landing is possible, at which point the victim and the rescuers are moved inside the helicopter cabin. During the winching procedure, the lying victim is immobilised on a spine board which is attached to a winching bag. Alternatively, the victim can also be winched in a sitting position using a harness or the KED1 system (Kendrick Extraction Device). The winching strategies are the same whether the method used is a traditional winching (where a steel cable with a hook is unrolled) or a human cargo sling (where a fixed length cable is attached directly to the helicopter). Methods We retrospectively reviewed all rescue missions conducted by Air-Glaciers from 1 January 2003 to 31 December 2008. The medical reports of the cases for which an emergency physician had been winched to the victim were collected. Cases where the emergency call clearly indicated that the victim was deceased were excluded. Data included the time from the emergency call to takeoff, the age and gender of the victim, the activity at the time of injury, the mechanism of injury, and the main body part injured as reported by the emergency physician. The severity of the illnesses or injuries was graded using the 7-level scale of the National Advisory Committee for Aeronautics (NACA) index7,8 by the emergency physician immediately after the rescue mission (1 = no need for acute physician care, 2 = therapy required without hospital admission, 3 = hospital admission, no vital threat, 4 = potentially life-threatening, 5 = acute threat to life, 6 = transport after successful resuscitation of vital signs, 7 = death, with or without reanimation efforts). Patients’ injuries were further pooled into minor (NACA 1), moderate (NACA 2–3), severe (NACA 4–6) or lethal (NACA 7) categories. The following medical procedures provided on-site were recorded: intravenous line access, fluid or drug administration, airway management, cardiopulmonary resuscitation, reduction of shoulder dislocation and femoral nerve blockade. Vasoactive drug administration (i.e., epinephrine, ephedrine or atropine), bag-mask ventilation, intubation, intravenous fluid administration of more than 1000 ml and cardiopulmonary resuscitation were defined as major life-saving procedures. Descriptive statistics were expressed as a mean and 95% CI or median with interquartile range, as appropriate. We explored differences in characteristics between patients using chi-square tests for categorical variables. We used two-sided p-values of <0.05 to assess statistical significance.
Table 1 Activity at the time of injury or medical emergency (n = 921). n (%) Mountaineering Downhill skiing Off-piste skiing Working Ski touring Snowboarding Driving a car Mountain biking Paragliding Hiking Othera
257 239 100 55 51 38 35 23 25 30 68
(28) (26) (11) (6) (6) (4) (4) (3) (3) (3) (7)
a Includes hunting (n = 6), housework (5), ice-skating (4), canyoning (2), hang gliding (2), water sports (2), parachuting (1), horseback riding (1), and unknown (n = 45).
Results 9879 rescue missions were conducted between 1 January 2003 and 31 December 2008. In 921 (9.3%) missions the emergency physician had to be winched. Characteristics of the victims and take-off time 621 (67%) of the 921 victims were male with a male:female ratio of 2:1, and a mean age of 41 years (SD 18), with a range of 2– 90 years. There were 56 (6%) paediatric patients (15 years). Most of the victims were injured whilst practising winter sports or mountain-related activities during the summer. A more detailed description of the respective activities of the victims at the time of injury is presented in Table 1. Falls accounted for the great majority of the trauma events (700 patients or 76%), followed by illnesses (81 patients or 9%). Of the 921 missions in which the physician was winched in the field, 28 (3%) were avalanche rescues and 13 (1%) were glacier crevasse rescues. The median time from emergency call to helicopter take-off was 7 min (IQR = 5–10 min, range 0– 280 min). Type and severity of injuries or illnesses Trauma to the upper and lower extremities accounted for 429 (47%) of all injuries, followed by 175 (19%) head injuries and 108 (12%) spinal lesions. Hypothermia, frostbite and altitude illnesses were diagnosed in 11 (1%) cases. In 128 (14%) cases two different diagnoses were made, and in 69 (7%) three or more diagnoses. The severity of the lesions as assessed by the NACA score is presented in Table 2. Potential or actual life-threatening injuries (NACA grades 4–6) were found in 246 (27%) victims. Medical patients had significantly more severe pathologies according to the NACA score when compared to trauma victims (p < 0.001) whereas the total number of medical victims was much smaller. Overall, 52 (6%) victims were dead at the scene (NACA 7). Forty-
Table 2 Injuries and medical emergencies by NACA score.
Minor-moderate (NACA 1–3)a Severe (NACA 4–6) Dead (NACA 7) Total number (%) a
Trauma victims (%)
Medical patientsb (%)
Total
584 210 46 840
39 36 6 81
623 246 52 921
(63) (23) (5) (91)
(4) (4) (1) (9)
(68) (27) (6) (100)
14 (2%) with NACA = 1; 216 (23%) with NACA = 2; 393 (43%) with NACA = 3. When compared to trauma victims, medical patients had significantly more severe pathologies according to the NACA index (Pearson’s chi-square test; p < 0.001). b
M. Pasquier et al. / Injury, Int. J. Care Injured 43 (2012) 1377–1380 Table 3 Main procedures performed at the scene of the incident (n = 921).
Intravenous lines Major analgesicsa Vasoactive drugsb,c Intubationc,d IV fluid administration > 1000 mlc Ventilationc Cardiopulmonary resuscitationc a b c d
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Characteristics of the patients and helicopter take-off time
n
%
574 478 26 16 16 7 7
62 52 2 2 2 1 1
Fentanyl (n = 443), ketamine (n = 42), morphine (n = 7). Epinephrine (n = 10), ephedrine (n = 10), atropine (n = 6). 72 major procedures on 39 (4%) patients. Including 10 rapid sequence intubations.
four of those (85%) were declared dead without reanimation attempts, usually in the context of trauma related asystolic arrests. Medical procedures The main medical interventions provided on-site are presented in Table 3. Major analgesia was administered to 478 (52%) victims, primarily with fentanyl (n = 443) followed by ketamine (n = 42) and morphine (n = 7). The mean dose of fentanyl was 188 micrograms, with a range from 25 to 750 micrograms. Only 267 (47%) of the patients with intravenous access received intravenous fluid therapy. On eight occasions, intra-nasal administration of fentanyl was used either because of failure to obtain an intravenous access, or as a first course of action in paediatric patients. Reductions of shoulder dislocations were performed six times and femoral blocks with ropivacaine in two cases of femoral fractures. No chest drain was placed. Major life-saving medical procedures, including ventilatory support and vascular filling onsite were provided to 39 (4%) patients. Intubation was performed 16 times, including 10 rapid sequence intubations. Apart from analgesics and vasoactive drugs, the most commonly used drugs were midazolam (n = 65 patients), droperidol (n = 30), acetylsalicylic acid (n = 11), nitroglycerin (n = 11), etomidate (n = 9), succinylcholine (n = 10), rocuronium (n = 7), and glucose (n = 4). Discussion Our results demonstrate that a total of 246 (27%) patients (both trauma and medical cases) suffered from severe injuries (NACA score of 4–6). Medical patients suffered from significantly more severe pathologies according to the NACA index (p < 0.001). Overall, 478 (52%) patients required administration of major analgesics, and most received fentanyl (mean dose of 188 micrograms, SD 127). Major life-saving medical interventions were performed on 39 (4%) patients. The data available in the literature about medical rescues involving helicopter winching procedures are extremely rare, and the best conducted and largest case series includes only 110 patients.9 Our 921-patient study is, to the best of our knowledge, by far the largest one to date. The high (9.3%) proportion of rescue flights involving winching can be explained by the alpine environment of the AG HEMS. Even lightly injured patients are typically rescued with a winch, as even minor injuries can result in severe and potentially life-threatening situations in high altitude or in a hostile or cold environment if transport is delayed. The rapidity of helicopter intervention helps to extract the victim and carry him to a secure and warm place or to the hospital in a timely manner. By avoiding manual transport of the victim on a stretcher, winching significantly shortens the rescue time and consequently the exposure of both the patient and the rescuers to environmental dangers.6
The data collected about the type of injuries and the activities at the time of injury are similar to the data related to non-winching missions conducted by AG, and with previous publications from other alpine or pre-alpine rescue teams.1,10 Some accident subgroups seem to require the use of the winch to a greater extent, such as paragliding accidents11 or avalanche rescues. The variety of environments (ski runs, rock or ice faces, icefalls, water) and technical requirements of some rescue operations (avalanche, canyon, glacier crevasse) demand highly trained crews. The specialisation of some crew members for very difficult interventions allows for greater critical mass and experience, and training sessions throughout the year including simulation exercises help refresh and maintain everyone’s skills. Although no comparative data are available in the literature, the median time to take-off of 7 min seems relatively short for such highly technical missions. Some longer delays were due to special conditions (poor meteorological conditions, night time) or unusual situations (simultaneous rescue missions). The concept of ‘‘rescue house’’, where all the crew members and materials are readily available in one location, no doubt contributed to this short time to take-off. In addition, this also improves safety, as the recommended pre-lift-off safety check and briefing involving all crew members can be expedited.12 Type and severity of injuries or illnesses The National Advisory Committee for Aeronautics (NACA) scale, developed during the Vietnam War and subsequently modified to allow its application to medical situations, is a simple score, utilisable in prehospital emergencies.7 It has been shown to adequately describe the life threat in trauma victims, and correlates well with morbidity and mortality, and to transfer to an intensive care unit.8 In an unselected population of patients rescued by medical helicopter or ground transport, the mortality rates for NACA levels 4, 5 and 6 were shown to be 8.7%, 15.3% and 63.2%, respectively.13 In another study, the 30-day survival rates were strongly and inversely associated with the severity of the emergency, as classified by the NACA score: NACA 4, 5, and 6 cases had a 30-day survival rate of 96.7%, 85.6%, and 12.8%, respectively.14 As 298 of all patients had an injury with a score between NACA 4 and 7, 32% of all rescue missions involved potential or overt vital threats. We found that victims of medical emergencies were in a higher NACA category (i.e., NACA 4–6 or severe life threat) significantly more often than trauma victims (44% versus 25%, respectively; p < 0.001). This finding is consistent with the results of another study that showed that in a helicopter-based emergency medical service, medical emergencies were correlated to poorer outcomes and lower survival rates when compared to traumatic injuries.14 Medical procedures Only 267 (47%) of the 574 patients with intravenous access received intravenous fluid therapy. This probably reflects a common practice of flushing the analgesic drugs with a saline bolus instead of with a perfusion. The reasons are first to shorten the time on-site, and second because perfusions are prone to freezing in the cold weather typically encountered in winter or at altitude. In a study of 57 patients with a head injury or multiple trauma rescued by a medically staffed helicopter equipped with a winch, rapid transport of a trained physician allowed prompt control of vital functions (respiration and circulation) at the scene of the accident,
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and was judged to be decisive in helping to prevent secondary cerebral injury.15 Helicopter transport and the influence of prehospital treatment have recently been shown to reduce the time to hospital and improve the outcomes of trauma.16–19 Early medical intervention appears to have been justified if one considers that 27% of all victims had a severe life threat (NACA 4–6), a high number of major medical interventions were provided on-site, and major analgesia was frequently administered. Although the number of rapid sequence intubations was low, it was sufficiently high to justify having personnel adequately trained in such procedures. In addition to purely medical procedures, the emergency physician also helps to stabilise the patient following PHTLS1 principles and rules, most of the time with immobilisation of the patient on a spine board.20 Haemostasis, fracture realignment and reductions (often after analgesia) and administration of oxygen, were not considered to be life-saving medical procedures and were therefore not identified in this study. Limitations Our study has several limitations. First, we were unable to validate the pre-hospital diagnosis made by the emergency physician or to determine in-hospital mortality because of the absence of related hospital follow-up in our database. The use of the NACA index has, however, been shown to correlate well with clinical outcomes in other studies.8,13 Second, we could not differentiate between the situations where only the patient was extracted using the winch. On some occasions, the rescue team and material can be discharged near the site with a winch during a stationary (hovering) flight, whilst the evacuation is conducted later through winching. However, this sequence of events is rare, as this procedure is considered riskier for the rescue team than is winching alone. Third, we could not distinguish between the administration of drugs and infusions on-site and during the flight to the hospital. However, given the short transport times (about 10 min from the site to the hospital) we have in our setting, this effect is probably minor. Finally, many ‘‘medical’’ interventions, including intubation, could easily have been carried out by advanced paramedics, if their training were as it is in some other countries. The external validity of our discussion or conclusions is therefore limited by these national differences. Conclusion About one third of patients involved in rescue winch operations had a potential or actual life threat. Since the use of helicopters as a rapid means with which to reach the victim and bring him to a secure place is well recognised, winching of physicians in the field allows for early administration of major analgesia and advanced life support measures. We believe the high number of technical and medical procedures provided directly on-site justify the winching of an emergency physician. Although not easily transferable to other helicopter-based medical services because of the regional differences between prehospital rescue epidemiology and strategies, this study allows for a better understanding and knowledge of medical aspects and capabilities in difficult rescue operations.
Conflict of interest None of the authors have any financial or personal relationships with other people or organisations to disclose that could have inappropriately influenced this work. Funding No external source of funding was used. No study sponsor was involved in any part of this work. Acknowledgment We thank Danielle Wyss for proofreading and final translation. References 1. Kaufmann M, Moser B, Lederer W. Changes in injury patterns and severity in a helicopter air-rescue system over a 6-year period. Wilderness Environ Med 2006;17:8–14. 2. Tomazin I, Kovacs T. Medical considerations in the use of helicopters in mountain rescue. ICAR-MEDCOM guidelines number 18. High Alt Med Biol 2003;4:479–83. 3. Hinkelbein J, Schwalbe M, Genzwuerker HV. Helicopter emergency medical services accident rates in different international air rescue systems. Open Access Emerg Med 2010;2:45–9. 4. Nicholl J, Turner J, Stevens K, O’keeffe C, Cross L, Goodacre S, et al. A review of the costs and benefits of Helicopter Emergency Ambulance Services in England and Wales. A report to the Department of Health. London: DH; 2003:1–73. 5. Flabouris A. A description of events associated with scene response by helicopter based medical retrieval teams. Injury 2003;34:847–52. 6. Ellerton J, Gilbert H. Should helicopters have a hoist or ‘long-line’ capability to perform mountain rescue in the UK? Emerg Med J 2010 October 28. [Epub ahead of print]. 7. Tryba M, Bru¨ggemann H, Echtermeyer V. Klassifizierung von Erkrankungen und Verletzungen im Notarztrettungssystemen. Notfallmedizin 1980;6:725–7. 8. Weiss M, Bernoulli L, Zollinger A. The NACA scale. Construct and predictive validity of the NACA scale for prehospital severity rating in trauma patients. Anaesthesist 2001;50:150–4. 9. Moeschler O, Refondini S, Ho¨fliger C, Freeman J. Difficult aeromedical rescue situations: experience of a Swiss pre-alpine helicopter base. J Trauma 1992;3:754–9. 10. Fischer MU. Aero-medical retrieval in extreme environment: the Zermatt experience. Trauma Care 2003;13:78–81. 11. Fasching G, Schippinger G, Pretscher R. Paragliding accidents in remote areas. Wilderness Environ Med 1997;8:129–33. 12. Grissom CK, Thomas F, James B. Medical helicopters in wilderness search and rescue operations. Air Med J 2006;25:18–25. 13. Sefrin P, Sellner J. Qualita¨tssicherung in der pra¨klinischen Notfallmedizin. Notfallmedizin 1993;19:267–74. 14. Bonatti J, Go¨schl O, Larcher P, Wo¨dlinger R, Flora G. Predictors of short-term survival after helicopter rescue. Resuscitation 1995;30:133–40. 15. Malacrida RL, Anselmi LC, Genoni M, Bogen M, Suter PM. Helicopter mountain rescue of patients with head injury and/or multiple injuries in southern Switzerland 1980–1990. Injury 1993;24:451–3. 16. Brown JB, Stassen NA, Bankey PE, Sangosanya AT, Cheng JD, Gestring ML. Helicopters and the civilian trauma system: national utilization patterns demonstrate improved outcomes after traumatic injury. J Trauma 2010;69:1030–4. 17. Berlot G, La Fata C, Bacer B, Biancardi B, Viviani M, Lucangelo U, et al. Influence of prehospital treatment on the outcome of patients with severe blunt traumatic brain injury: a single-centre study. Eur J Emerg Med 2009;16:312–7. 18. Ryyna¨nen OP, Iirola T, Reitala J, Pa¨lve H, Malmivaara A. Is advanced life support better than basic life support in prehospital care? A systematic review. Scand J Trauma Resusc Emerg Med 2010;18:62. 19. Yeguiayan JM, Garrigue D, Binquet C, Jacquot C, Duranteau J, Martin C, et al. Medical pre-hospital management reduces mortality in severe blunt trauma: a prospective epidemiological study. Crit Care 2011;15:R34. [Epub ahead of print]. 20. National Association of Emergency Medical Technicians. PHTLS prehospital trauma life support. 7th ed. St. Louis: Elsevier Mosby JEMS; 2011.
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Helicopter rescue operations involving winching of an emergency physician M. Pasquier a,b,*, V. Geiser a, M. De Riedmatten b, P.N. Carron a a b
Emergency Service, University Hospital Center, Lausanne, Switzerland Air-Glaciers, Maison FXB du Sauvetage, Sion, Switzerland
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 22 June 2011
Objective: We sought to study the epidemiologic and medical aspects of alpine helicopter rescue operations involving the winching of an emergency physician to the victim. Methods: We retrospectively reviewed the medical and operational reports of a single helicopter-based emergency medical service. Data from 1 January 2003 to 31 December 2008 were analysed. Results: A total of 921 patients were identified, with a male:female ratio of 2:1. There were 56 (6%) patients aged 15 or under. The median time from emergency call to helicopter take-off was 7 min (IQR = 5–10 min). 840 (91%) patients suffered from trauma-related injuries, with falls from heights during sports activities the most frequent event. The most common injuries involved the legs (246 or 27%), head (175 or 19%), upper limbs (117 or 13%), spine (108 or 12%), and femur (66 or 7%). Only 81 (9%) victims suffered from a medical emergency, but these cases were, when compared to the trauma victims, significantly more severe according to the NACA index (p < 0.001). Overall, 246 (27%) patients had a severe injury or illness, namely, a potential or overt vital threat (NACA score between 4 and 6). A total of 478 (52%) patients required administration of major analgesics: fentanyl (443 patients or 48%), ketamine (42 patients or 5%) or morphine (7 patients or 1%). The mean dose of fentanyl was 188 micrograms (range 25–750, SD 127). Major medical interventions such as administration of vasoactive drugs, intravenous perfusions of more than 1000 ml of fluids, ventilation or intubation were performed on 39 (4%) patients. Conclusions: The severity of the patients’ injuries or illnesses along with the high proportion of medical procedures performed directly on-site validates emergency physician winching for advanced life support procedures and analgesia. ß 2011 Elsevier Ltd. All rights reserved.
Keywords: Air ambulance Aircraft Emergency medical services Mountaineering Rescue work Switzerland
Introduction The number of helicopter-based emergency medical services (HEMS) rescue operations for people involved in outdoor leisure activities has increased over the last few years.1 Helicopter rescues offer several advantages over ground transport, including the ability to perform air searches for lost victims, rapidly shuttle rescue personnel and equipment to the scene, deliver timely onsite advanced medical care decreasing both the number of rescuers required for ground evacuation and exposure to hazards associated with hostile environments, and reduce patient transport time to the hospital.2 On the other hand, HEMS operations have higher accident and fatality rates when compared to helicopter operations in other fields.3 The risk factors include night flight and poor weather, the latter being frequently the case during mountain rescues.4 Winching procedures account for a non-negligible
* Corresponding author at: Emergency Service, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland. Tel.: +41 79 556 34 22; fax: +41 21 314 08 71. E-mail address: [email protected] (M. Pasquier). 0020–1383/$ – see front matter ß 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2011.06.196
number of incidents during rescue missions,5 and therefore are not used by all HEMS and in all countries.6 Whereas the use of helicopters as a rapid means to reach victims and to bring them to a secure place is well-recognised, there are very few data available about the value of winching physicians to provide medical care for the victims directly on-site. We analysed the medical aspects of helicopter rescue operations involving winching of an emergency physician in a Swiss setting. Air-Glaciers’ helicopter-based emergency medical service Air-Glaciers (AG) is a commercial rescue company founded in 1965 based in the heart of the Alps in Sion, Switzerland. This helicopter-based emergency medical service covers a resident population of about 220,000, and grows significantly during the peak tourist seasons in winter and summer. AG intervenes at altitudes from 500 to over 4000 metres, with a time of flight from the base to the scene of generally less of 20 min. The base covers an operational area of 250 km2. About 1700 rescue flights are made each year, of which more than 90% are primary missions ranging from road traffic accidents to high altitude
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mountain rescues, whilst 10% are interhospital transfers. Most of the patients are admitted either to the local trauma and medical centre of Sion which has neurosurgery, cardiovascular surgery, intensive care and coronary angioplasty services, or to the nearby University Hospital of Lausanne. Operational aspects The AG’s base station can simultaneously deploy up to 5 helicopters equipped with medical staff during the peak tourist season. It is the only service operating in this geographical area, although helicopters from other companies can be engaged in a one-off basis for extraordinary circumstances. All rescue missions requiring a winch strategy also include a mountain guide with a paramedical training. Depending on the presumed severity of the medical situation, an emergency physician is winched either as a first course of action, or as recommended after the mountain guide’s initial evaluation of the situation. A spine board, a monitor/ defibrillator, an electric suction device and a medical bag with advanced life support material (intubation and resuscitation drugs) are taken on-site by the rescuers as needed. After immobilisation and stabilisation of the patient, extrication with the winch is followed by a short flight until landing is possible, at which point the victim and the rescuers are moved inside the helicopter cabin. During the winching procedure, the lying victim is immobilised on a spine board which is attached to a winching bag. Alternatively, the victim can also be winched in a sitting position using a harness or the KED1 system (Kendrick Extraction Device). The winching strategies are the same whether the method used is a traditional winching (where a steel cable with a hook is unrolled) or a human cargo sling (where a fixed length cable is attached directly to the helicopter). Methods We retrospectively reviewed all rescue missions conducted by Air-Glaciers from 1 January 2003 to 31 December 2008. The medical reports of the cases for which an emergency physician had been winched to the victim were collected. Cases where the emergency call clearly indicated that the victim was deceased were excluded. Data included the time from the emergency call to takeoff, the age and gender of the victim, the activity at the time of injury, the mechanism of injury, and the main body part injured as reported by the emergency physician. The severity of the illnesses or injuries was graded using the 7-level scale of the National Advisory Committee for Aeronautics (NACA) index7,8 by the emergency physician immediately after the rescue mission (1 = no need for acute physician care, 2 = therapy required without hospital admission, 3 = hospital admission, no vital threat, 4 = potentially life-threatening, 5 = acute threat to life, 6 = transport after successful resuscitation of vital signs, 7 = death, with or without reanimation efforts). Patients’ injuries were further pooled into minor (NACA 1), moderate (NACA 2–3), severe (NACA 4–6) or lethal (NACA 7) categories. The following medical procedures provided on-site were recorded: intravenous line access, fluid or drug administration, airway management, cardiopulmonary resuscitation, reduction of shoulder dislocation and femoral nerve blockade. Vasoactive drug administration (i.e., epinephrine, ephedrine or atropine), bag-mask ventilation, intubation, intravenous fluid administration of more than 1000 ml and cardiopulmonary resuscitation were defined as major life-saving procedures. Descriptive statistics were expressed as a mean and 95% CI or median with interquartile range, as appropriate. We explored differences in characteristics between patients using chi-square tests for categorical variables. We used two-sided p-values of <0.05 to assess statistical significance.
Table 1 Activity at the time of injury or medical emergency (n = 921). n (%) Mountaineering Downhill skiing Off-piste skiing Working Ski touring Snowboarding Driving a car Mountain biking Paragliding Hiking Othera
257 239 100 55 51 38 35 23 25 30 68
(28) (26) (11) (6) (6) (4) (4) (3) (3) (3) (7)
a Includes hunting (n = 6), housework (5), ice-skating (4), canyoning (2), hang gliding (2), water sports (2), parachuting (1), horseback riding (1), and unknown (n = 45).
Results 9879 rescue missions were conducted between 1 January 2003 and 31 December 2008. In 921 (9.3%) missions the emergency physician had to be winched. Characteristics of the victims and take-off time 621 (67%) of the 921 victims were male with a male:female ratio of 2:1, and a mean age of 41 years (SD 18), with a range of 2– 90 years. There were 56 (6%) paediatric patients (15 years). Most of the victims were injured whilst practising winter sports or mountain-related activities during the summer. A more detailed description of the respective activities of the victims at the time of injury is presented in Table 1. Falls accounted for the great majority of the trauma events (700 patients or 76%), followed by illnesses (81 patients or 9%). Of the 921 missions in which the physician was winched in the field, 28 (3%) were avalanche rescues and 13 (1%) were glacier crevasse rescues. The median time from emergency call to helicopter take-off was 7 min (IQR = 5–10 min, range 0– 280 min). Type and severity of injuries or illnesses Trauma to the upper and lower extremities accounted for 429 (47%) of all injuries, followed by 175 (19%) head injuries and 108 (12%) spinal lesions. Hypothermia, frostbite and altitude illnesses were diagnosed in 11 (1%) cases. In 128 (14%) cases two different diagnoses were made, and in 69 (7%) three or more diagnoses. The severity of the lesions as assessed by the NACA score is presented in Table 2. Potential or actual life-threatening injuries (NACA grades 4–6) were found in 246 (27%) victims. Medical patients had significantly more severe pathologies according to the NACA score when compared to trauma victims (p < 0.001) whereas the total number of medical victims was much smaller. Overall, 52 (6%) victims were dead at the scene (NACA 7). Forty-
Table 2 Injuries and medical emergencies by NACA score.
Minor-moderate (NACA 1–3)a Severe (NACA 4–6) Dead (NACA 7) Total number (%) a
Trauma victims (%)
Medical patientsb (%)
Total
584 210 46 840
39 36 6 81
623 246 52 921
(63) (23) (5) (91)
(4) (4) (1) (9)
(68) (27) (6) (100)
14 (2%) with NACA = 1; 216 (23%) with NACA = 2; 393 (43%) with NACA = 3. When compared to trauma victims, medical patients had significantly more severe pathologies according to the NACA index (Pearson’s chi-square test; p < 0.001). b
M. Pasquier et al. / Injury, Int. J. Care Injured 43 (2012) 1377–1380 Table 3 Main procedures performed at the scene of the incident (n = 921).
Intravenous lines Major analgesicsa Vasoactive drugsb,c Intubationc,d IV fluid administration > 1000 mlc Ventilationc Cardiopulmonary resuscitationc a b c d
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Characteristics of the patients and helicopter take-off time
n
%
574 478 26 16 16 7 7
62 52 2 2 2 1 1
Fentanyl (n = 443), ketamine (n = 42), morphine (n = 7). Epinephrine (n = 10), ephedrine (n = 10), atropine (n = 6). 72 major procedures on 39 (4%) patients. Including 10 rapid sequence intubations.
four of those (85%) were declared dead without reanimation attempts, usually in the context of trauma related asystolic arrests. Medical procedures The main medical interventions provided on-site are presented in Table 3. Major analgesia was administered to 478 (52%) victims, primarily with fentanyl (n = 443) followed by ketamine (n = 42) and morphine (n = 7). The mean dose of fentanyl was 188 micrograms, with a range from 25 to 750 micrograms. Only 267 (47%) of the patients with intravenous access received intravenous fluid therapy. On eight occasions, intra-nasal administration of fentanyl was used either because of failure to obtain an intravenous access, or as a first course of action in paediatric patients. Reductions of shoulder dislocations were performed six times and femoral blocks with ropivacaine in two cases of femoral fractures. No chest drain was placed. Major life-saving medical procedures, including ventilatory support and vascular filling onsite were provided to 39 (4%) patients. Intubation was performed 16 times, including 10 rapid sequence intubations. Apart from analgesics and vasoactive drugs, the most commonly used drugs were midazolam (n = 65 patients), droperidol (n = 30), acetylsalicylic acid (n = 11), nitroglycerin (n = 11), etomidate (n = 9), succinylcholine (n = 10), rocuronium (n = 7), and glucose (n = 4). Discussion Our results demonstrate that a total of 246 (27%) patients (both trauma and medical cases) suffered from severe injuries (NACA score of 4–6). Medical patients suffered from significantly more severe pathologies according to the NACA index (p < 0.001). Overall, 478 (52%) patients required administration of major analgesics, and most received fentanyl (mean dose of 188 micrograms, SD 127). Major life-saving medical interventions were performed on 39 (4%) patients. The data available in the literature about medical rescues involving helicopter winching procedures are extremely rare, and the best conducted and largest case series includes only 110 patients.9 Our 921-patient study is, to the best of our knowledge, by far the largest one to date. The high (9.3%) proportion of rescue flights involving winching can be explained by the alpine environment of the AG HEMS. Even lightly injured patients are typically rescued with a winch, as even minor injuries can result in severe and potentially life-threatening situations in high altitude or in a hostile or cold environment if transport is delayed. The rapidity of helicopter intervention helps to extract the victim and carry him to a secure and warm place or to the hospital in a timely manner. By avoiding manual transport of the victim on a stretcher, winching significantly shortens the rescue time and consequently the exposure of both the patient and the rescuers to environmental dangers.6
The data collected about the type of injuries and the activities at the time of injury are similar to the data related to non-winching missions conducted by AG, and with previous publications from other alpine or pre-alpine rescue teams.1,10 Some accident subgroups seem to require the use of the winch to a greater extent, such as paragliding accidents11 or avalanche rescues. The variety of environments (ski runs, rock or ice faces, icefalls, water) and technical requirements of some rescue operations (avalanche, canyon, glacier crevasse) demand highly trained crews. The specialisation of some crew members for very difficult interventions allows for greater critical mass and experience, and training sessions throughout the year including simulation exercises help refresh and maintain everyone’s skills. Although no comparative data are available in the literature, the median time to take-off of 7 min seems relatively short for such highly technical missions. Some longer delays were due to special conditions (poor meteorological conditions, night time) or unusual situations (simultaneous rescue missions). The concept of ‘‘rescue house’’, where all the crew members and materials are readily available in one location, no doubt contributed to this short time to take-off. In addition, this also improves safety, as the recommended pre-lift-off safety check and briefing involving all crew members can be expedited.12 Type and severity of injuries or illnesses The National Advisory Committee for Aeronautics (NACA) scale, developed during the Vietnam War and subsequently modified to allow its application to medical situations, is a simple score, utilisable in prehospital emergencies.7 It has been shown to adequately describe the life threat in trauma victims, and correlates well with morbidity and mortality, and to transfer to an intensive care unit.8 In an unselected population of patients rescued by medical helicopter or ground transport, the mortality rates for NACA levels 4, 5 and 6 were shown to be 8.7%, 15.3% and 63.2%, respectively.13 In another study, the 30-day survival rates were strongly and inversely associated with the severity of the emergency, as classified by the NACA score: NACA 4, 5, and 6 cases had a 30-day survival rate of 96.7%, 85.6%, and 12.8%, respectively.14 As 298 of all patients had an injury with a score between NACA 4 and 7, 32% of all rescue missions involved potential or overt vital threats. We found that victims of medical emergencies were in a higher NACA category (i.e., NACA 4–6 or severe life threat) significantly more often than trauma victims (44% versus 25%, respectively; p < 0.001). This finding is consistent with the results of another study that showed that in a helicopter-based emergency medical service, medical emergencies were correlated to poorer outcomes and lower survival rates when compared to traumatic injuries.14 Medical procedures Only 267 (47%) of the 574 patients with intravenous access received intravenous fluid therapy. This probably reflects a common practice of flushing the analgesic drugs with a saline bolus instead of with a perfusion. The reasons are first to shorten the time on-site, and second because perfusions are prone to freezing in the cold weather typically encountered in winter or at altitude. In a study of 57 patients with a head injury or multiple trauma rescued by a medically staffed helicopter equipped with a winch, rapid transport of a trained physician allowed prompt control of vital functions (respiration and circulation) at the scene of the accident,
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and was judged to be decisive in helping to prevent secondary cerebral injury.15 Helicopter transport and the influence of prehospital treatment have recently been shown to reduce the time to hospital and improve the outcomes of trauma.16–19 Early medical intervention appears to have been justified if one considers that 27% of all victims had a severe life threat (NACA 4–6), a high number of major medical interventions were provided on-site, and major analgesia was frequently administered. Although the number of rapid sequence intubations was low, it was sufficiently high to justify having personnel adequately trained in such procedures. In addition to purely medical procedures, the emergency physician also helps to stabilise the patient following PHTLS1 principles and rules, most of the time with immobilisation of the patient on a spine board.20 Haemostasis, fracture realignment and reductions (often after analgesia) and administration of oxygen, were not considered to be life-saving medical procedures and were therefore not identified in this study. Limitations Our study has several limitations. First, we were unable to validate the pre-hospital diagnosis made by the emergency physician or to determine in-hospital mortality because of the absence of related hospital follow-up in our database. The use of the NACA index has, however, been shown to correlate well with clinical outcomes in other studies.8,13 Second, we could not differentiate between the situations where only the patient was extracted using the winch. On some occasions, the rescue team and material can be discharged near the site with a winch during a stationary (hovering) flight, whilst the evacuation is conducted later through winching. However, this sequence of events is rare, as this procedure is considered riskier for the rescue team than is winching alone. Third, we could not distinguish between the administration of drugs and infusions on-site and during the flight to the hospital. However, given the short transport times (about 10 min from the site to the hospital) we have in our setting, this effect is probably minor. Finally, many ‘‘medical’’ interventions, including intubation, could easily have been carried out by advanced paramedics, if their training were as it is in some other countries. The external validity of our discussion or conclusions is therefore limited by these national differences. Conclusion About one third of patients involved in rescue winch operations had a potential or actual life threat. Since the use of helicopters as a rapid means with which to reach the victim and bring him to a secure place is well recognised, winching of physicians in the field allows for early administration of major analgesia and advanced life support measures. We believe the high number of technical and medical procedures provided directly on-site justify the winching of an emergency physician. Although not easily transferable to other helicopter-based medical services because of the regional differences between prehospital rescue epidemiology and strategies, this study allows for a better understanding and knowledge of medical aspects and capabilities in difficult rescue operations.
Conflict of interest None of the authors have any financial or personal relationships with other people or organisations to disclose that could have inappropriately influenced this work. Funding No external source of funding was used. No study sponsor was involved in any part of this work. Acknowledgment We thank Danielle Wyss for proofreading and final translation. References 1. Kaufmann M, Moser B, Lederer W. Changes in injury patterns and severity in a helicopter air-rescue system over a 6-year period. Wilderness Environ Med 2006;17:8–14. 2. Tomazin I, Kovacs T. Medical considerations in the use of helicopters in mountain rescue. ICAR-MEDCOM guidelines number 18. High Alt Med Biol 2003;4:479–83. 3. Hinkelbein J, Schwalbe M, Genzwuerker HV. Helicopter emergency medical services accident rates in different international air rescue systems. Open Access Emerg Med 2010;2:45–9. 4. Nicholl J, Turner J, Stevens K, O’keeffe C, Cross L, Goodacre S, et al. A review of the costs and benefits of Helicopter Emergency Ambulance Services in England and Wales. A report to the Department of Health. London: DH; 2003:1–73. 5. Flabouris A. A description of events associated with scene response by helicopter based medical retrieval teams. Injury 2003;34:847–52. 6. Ellerton J, Gilbert H. Should helicopters have a hoist or ‘long-line’ capability to perform mountain rescue in the UK? Emerg Med J 2010 October 28. [Epub ahead of print]. 7. Tryba M, Bru¨ggemann H, Echtermeyer V. Klassifizierung von Erkrankungen und Verletzungen im Notarztrettungssystemen. Notfallmedizin 1980;6:725–7. 8. Weiss M, Bernoulli L, Zollinger A. The NACA scale. Construct and predictive validity of the NACA scale for prehospital severity rating in trauma patients. Anaesthesist 2001;50:150–4. 9. Moeschler O, Refondini S, Ho¨fliger C, Freeman J. Difficult aeromedical rescue situations: experience of a Swiss pre-alpine helicopter base. J Trauma 1992;3:754–9. 10. Fischer MU. Aero-medical retrieval in extreme environment: the Zermatt experience. Trauma Care 2003;13:78–81. 11. Fasching G, Schippinger G, Pretscher R. Paragliding accidents in remote areas. Wilderness Environ Med 1997;8:129–33. 12. Grissom CK, Thomas F, James B. Medical helicopters in wilderness search and rescue operations. Air Med J 2006;25:18–25. 13. Sefrin P, Sellner J. Qualita¨tssicherung in der pra¨klinischen Notfallmedizin. Notfallmedizin 1993;19:267–74. 14. Bonatti J, Go¨schl O, Larcher P, Wo¨dlinger R, Flora G. Predictors of short-term survival after helicopter rescue. Resuscitation 1995;30:133–40. 15. Malacrida RL, Anselmi LC, Genoni M, Bogen M, Suter PM. Helicopter mountain rescue of patients with head injury and/or multiple injuries in southern Switzerland 1980–1990. Injury 1993;24:451–3. 16. Brown JB, Stassen NA, Bankey PE, Sangosanya AT, Cheng JD, Gestring ML. Helicopters and the civilian trauma system: national utilization patterns demonstrate improved outcomes after traumatic injury. J Trauma 2010;69:1030–4. 17. Berlot G, La Fata C, Bacer B, Biancardi B, Viviani M, Lucangelo U, et al. Influence of prehospital treatment on the outcome of patients with severe blunt traumatic brain injury: a single-centre study. Eur J Emerg Med 2009;16:312–7. 18. Ryyna¨nen OP, Iirola T, Reitala J, Pa¨lve H, Malmivaara A. Is advanced life support better than basic life support in prehospital care? A systematic review. Scand J Trauma Resusc Emerg Med 2010;18:62. 19. Yeguiayan JM, Garrigue D, Binquet C, Jacquot C, Duranteau J, Martin C, et al. Medical pre-hospital management reduces mortality in severe blunt trauma: a prospective epidemiological study. Crit Care 2011;15:R34. [Epub ahead of print]. 20. National Association of Emergency Medical Technicians. PHTLS prehospital trauma life support. 7th ed. St. Louis: Elsevier Mosby JEMS; 2011.