American Journal of Emergency Medicine (2012) 30, 1591-1596

Brief Report

An example of extreme cardiology: chest pain on the high seas and helicoptered medical evacuations

The French Navy experience

Ulric Vinsonneau MD^a,?, Christiane Cavel MD^a, Christophe Bombert MD^b, Laurent Lely MD^b, Nicolas Paleiron MD^a, Claude Vergez-Larrouget MD^b, Jean-Christophe Cornily MD^c, Philippe Castellant MD^c, Martine Gilard PR^c,

Paule Paule MD^a, Jean-Ariel Bronstein MD^a

^aClermont Tonnerre Hospital of Military Training, Brest BP41 BCRM 29240 Brest Cedex 9, France

^bMedical Center of the Defense Base Armies of Brest-Lorient, Brest BCRM CC 74 29 240 Brest Cedex 9, France

^cDepartment of Cardiology, La Cavale Blanche University Hospital, Boulevard Tanguy Prigent 29200 Brest, France

Received 7 August 2011; revised 9 October 2011; accepted 10 October 2011

Abstract Medicalized high sea rescue is very different from prehospital medical evacuation. It requires specifically trained medical teams because the difficulties are marine, aerial, and medically related. The French Navy provides medical evacuations by helicopter on the Atlantic coast, up to 320 km offshore and under all Weather conditions. The epidemiology of acute chest pain in the high seas has been poorly described. Therefore, in this retrospective study, we aimed to assess the prevalence and constraints found in the management of these emergencies.

From January 1, 2000, to April 30, 2009, 286 medical evacuations by helicopter were performed, 132 of which were due to traumatological emergencies, and 154 to Medical emergencies. Acute chest pain, with 36 missions, was the leading cause of medical evacuation. All evacuated patients were men who were either professional sailors or ferry passengers. The median age was 48 years (range, 26-79). The most common prehospital diagnosis was coronary chest pain in 23 patients (64%), including 11 patients with acute coronary syndrome with ST-segment elevation. Thirty-two patients were airlifted by helicopter. All patients benefited from monitoring, electrocardiogram, peripheral venous catheter, and medical management as soon as the technical conditions allowed it.

(C) 2012

Introduction

* Corresponding author. Department of Cardiology, Clermont Ton- nerre Hospital of Military Training, Brest BP41 BCRM 29240 Brest Cedex 9, France.

E-mail address: [email protected] (U. Vinsonneau).

The ocean off the tip of Brittany is one of the busiest sea routes in the world. Indeed, 25% of the world’s seaborne trade (oil tankers, ferries, fishing vessels, yachts, and warships) runs off Brittany to gain access to the major ports in the North Sea. The navy provides medical evacuation missions (medevac) on the high seas of the peninsula of Crozon with

0735-6757/$ - see front matter (C) 2012 doi:10.1016/j.ajem.2011.10.013

Lanveoc-Poulmic helicopters. Since the early 1970s, 24/7 permanence has allowed for the rescue and treatment of more than 1,000 people. Medical studies devoted to medical transport on the high seas are rare. Through this work, we aimed to describe the epidemiology and constraints encoun- tered in the management of acute chest pain.

Procedure of a medical evacuation by helicopter on the high seas

The course of an offshore medevac is divided into 3 phases: (1) Phase 1: alert; (2) Phase 2: rescue, and (3) phase 3: transport to the hospital. Phase 1 includes the decision of an aeromedical evacuation after a medical evaluation and transit time to the area. Phase 2 corresponds to the extraction of the patient and is the most dangerous phase. After localization of the applicant ship, the pilot hovers above the ship. The diver is airlifted in a few seconds, followed by the physician. Once on the boat, if the conditions are favorable, the doctor starts patient management and conditioning for the helicopter hoist. This is usually completed on a stretcher and sometimes with a strap. Phase 3 is the evacuation of the patient to the hospital. Once aboard the helicopter, the medicalization of the patient continues until the hospital is reached.

Materials and methods

This was a retrospective, descriptive, monocenter study performed over a 9-year period, from January 1, 2000, to April 30, 2009. The inclusion criterion was the occurrence of acute chest pain while the patient was on the high seas, which required helicoptered medical evacuation. Patients treated in the framework of a mission to rescue shipwreck survivors and nonmedical interventions were excluded. Medical data were collected from the registry established by the Lanveoc- Poulmic medical service. Weather data were collected by the Meteo France weather service.

The registry of medicalized evacuations recorded the initial reason for evacuation for each patient, the patient’s personal details (age, occupation), and the time of first medical contact, defined by the time between the first symptom and the first contact with medical agents. This period was called “early” if it occurred in less than 3 hours, “moderate” between 3 and 12 hours, and “tardive” when longer than 12 hours. The registry

also contained medical data, such as Cardiovascular risk factors (treated or untreated dyslipidemia, treated or untreated hypertension, smoking, and presence of treated or untreated diabetes). The initial clinical examination was codified according to the NACA aeronautics Clinical score (Fig. 1), prehospital diagnosis, initial management, and changes during transportation, and the final diagnosis was validated by the receiving hospital. The registry also recorded data regarding the aircraft mission (time, season, distance in nautical miles, visibility in nautical miles, wave height, and wind speed according to the Beaufort scale) and the hoist technique (stretcher or belt).

Results

During this period of 9 years and 4 months, Lanveoc crews performed 286 medicalized evacuations, 154 (54%) of which were for Medical causes and 132 (46%) for traumatology emergencies. Thirty-six patients (23%) were evacuated because of acute chest pain.

Most evacuations took place during the day (n = 21, 58.3%), and there was no seasonal pattern (14 autumn, 10 cases winter). The average distance of intervention was 72 nautical miles, equivalent to 133 km. There were 2 main Geographical areas of intervention: an offshore fishing area located near the continental shelf between 90 and 100 nautical miles (between 165 and 185 km; n = 6) and the southbound/northbound lane of Ushant, located about 50 nautical miles off the coast (at 90 and 110 km). Twenty-two evacuations (61%) were carried out on a sea of force greater than or equal to 3 Beaufort. The average wind speed was 19 knots (35 km/h), corresponding to a force of 5 Beaufort, with extremes at 5 and 60 knots. In a medevac, phase 1 lasted 91 minutes on average, with extremes of 30 and 244 minutes. The average length of phase 2 was 30 minutes. Transport to the hospital was done in an average of 33 minutes. The doctor was winched down on the ship in 28 (78%) missions. The patient was hoisted by a stretcher in 26 (69%) missions and by a belt in 6 cases (16%) (Table 1). All patients underwent monitoring, electrocardi- ography (ECG), and peripheral venous catheter insertion as soon as the technical conditions allowed it.

All 36 patients studied were men. The median age was 48 years (range, 26-79). The major cardiovascular risk factor was age, with 17 (47.2%) patients aged 50 years or more,

S Severity

0 No disease or injury

1 Non-acute. life-threatening disease or injury

2 Acute intervention not necessary. further diagnostic studies required

0

N di i j

3 Severe but not life-threatening disease or injury. Acute intervention necessary

4 Development of vital (life-threatening) possible danger

5 Acute vital (life threatening) danger

6 Acute cardiac or respiratory arrest

7 Death

Fig. 1 Severity of disease or injury according to the Norwegian National Advisory Committee for Aeronautics (NACA score).

Table 1 Aeronautical characteristics of the missions (N = 36)

24-h distribution

seasonal distribution Wind (Beaufort scale)

Wave height (Beaufort scale)

Visibility Distance (NM) 0-50

50-100

N100

Mission length (min) Total

Alert (phase 1) On zone (phase 2)

Transport (phase 3) Hoist

Patients Doctor Nurse

Day: n = 21 (58%); night: n = 15

(42%)

n = 24 (67%) during the winter n = 7 (19.5%), N33 Knots (gale) n = 12 (33%), N4 (N1.5 m)

n = 8 (22%), b1500 m

n = 27 (75%), N50 NM (N 90 km)

n = 9 (25%)

n = 20 (55%)

n = 7 (19%)

159 (83-321)

86 (30-244)

30 (4-98)

33 (5-67)

n = 32

n = 32; strap, n = 6; stretcher, n = 26 n = 28 (78%)

n = 3 (8%)

n indicates number of missions; NM, nautical miles.

followed by smoking, with 14 patients (38.8%). Dyslipide- mia was found in 12 patients (33.3%), and 3 of the patients were diabetic (8.3%). In our study, 21 (58.3%) patients received medical care early or in less than 3 hours, and 13 of them were classified as tardive (36.1%). The average NACA index of clinical severity was 4.4 (2-6), and the median was

1. Two patients were determined to be in cardiopulmonary arrest at the doctor’s arrival (Table 2).

Considering the 36 studied cases, prehospital diagnosis was coronary chest pain in 23 of them (64%), 11 of which showed an acute coronary syndrome with ST-segment elevation (STEMI), and the other 12, acute coronary syndrome without ST-segment elevation (NSTEMI). Noncoronary chest pains were recorded for 13 patients (36%), including 2 pericarditis, 1 symptomatic atrial fibrillation, 1 lung disease, and 9 so-called Atypical chest pains (25%). All study patients benefited from a peripheral

Table 2 General characteristics of the patients

intravenous (IV) device, oxygen therapy, and monitoring. Of the 11 patients presentinga STEMI, 2 were determined to be in cardiopulmonary arrest at the doctor’s arrival and received cardiopulmonary resuscitation. One patient was treated by thrombolysis with Alteplase within 3 hours of pain onset. Two STEMI were complicated by ventricular fibrillation and required external Electrical shocks associated with an Amiodar- one perfusion. Nine patients received Antiplatelet therapy with IV aspirin at a dose of 250 mg together with low-molecular- weight heparin (LMWH) subcutaneously at a curative dose. Intravenous nitrates were used in 7 patients. Seven patients received Clopidogrel (four tablets) orally, once hoistered.

The management of the 12 NSTEMI patients was done with combined antiplatelet therapy with 250 mg IV aspirin, and LMWH subcutaneously was added in 7 of them. Clopidogrel was used in 9 patients always after being hoistered. Nitro derivatives were used in 8 patients. The management of noncoronary pain was symptomatic with the use of analgesics and IV aspirin in 6 patients (Table 3).

During transport, 1 patient developed a desaturation secondary to lung edema, and 1 patient experienced a rise in blood pressure immediately after winching. The remaining patient was a victim of motion sickness, complicated by vomiting. Two patients died during the 36 missions (8%). The 34 successfully transported patients were all hospitalized. The prehospital diagnosis was confirmed in 11 of 11 patients diagnosed with STEMI and 4 of 12 patients diagnosed with NSTEMI. Twenty-one noncoronary chest pains (3 atrial fibrillation, 5 pericarditis, 2 pneumonia, and 11 atypical chest pains) were recorded. Fifteen (42%) diagnoses were later corrected in total (Table 4).

4. Discussion

The helicoptered medicalized evacuations starting at the site of Lanveoc-Poulmic are offshore missions, with a long transit time, which accounts for two thirds of the mission

Professional sailors (n = 26, 72.2%)		Ferry passengers (n = 9, 25%)	State marines (n = 1, 2%)		Total (N = 36)
Age (y)	44 (28-57)	62 (52-79)	36		48 (28-79)
Age N50 y	8 (22.2%)	9 (25%)	0		17 (47.2%)
Hypertension	3 (8.3%)	3 (8.3%)	0		6 (16.6%)
Diabetes	1 (2.7%)	2 (5.5%)	0		3 (8.3%)
Smoking	10 (27.7%)	3 (8.3%)	1	(2.7%)	14 (38.8%)
Dyslipidemia	8 (22 .2%)	3 (8.3%)	1	(2.7%)	12 (33.3%)
HSTR CP	3 (8.3%)	4 (11%)	0		7 (19.4%)
FMCD
b3 H	12	8	1		21 (58.3%)
3h b X b 12H	1	1	0		2 (5.5%)
N12H	12	1	0		13 (36.2%)
NACA score (average)	4.3	4.2	5		4.8
HSTR CP indicates history of coronary pathologies; FMCD, first medical contact delay.

Pathologies	Therapy before winching	Therapy after winching
STEMI (n = 11)	ASA (n = 11), ECM (n = 2), Epi (n = 2)	O2 (n = 11), thrombolysis (n = 1), LMWH (n = 9),
		clopidogrel (n = 7), ND (n = 7), furosemide (n = 1),
		ANA (n = 4), amiodarone (n = 2)
NSTEMI (n = 12)	ASA (n = 12)	O2 (n = 12), clopidogrel (n = 9), LMWH (n = 7),
		ND (n = 8), ANA (n = 4)
Pericarditis (n = 2)	ASA (n = 2), ANA (n = 2)	O2 (n = 2)
Atrial fibrillation (n = 1)		O2, LMWH, ANA
Pneumonia (n = 1)		O2, ANA, ATB
Atypical chest pain (n = 9)	ASA (n = 3)	O2, ANA (n = 5), B2a (n = 1), ND (n = 2)
ASA indicates aspirin; ANA, analgesic; ATB, antibiotics; ND, nitro derivatives; B2a, ?2 agonist; PVR, peripheral vein route; ECM, external cardiac massage; Epi, epinephrine. Monitoring: blood pressure, heart rhythm, and O2.

time, with 42% of the flights taking place at night and in difficult weather conditions. These missions are conducted for the benefit of seriously ill patients, as 56% of the rescued patients presented a life-threatening prognosis.

Table 3 Medical management of acute chest pain (prehospital diagnosis) before and after winching (monitoring PVR and ECG as soon as possible)

These missions require significant offshore resources, both aeronautical and medical. In France, the commissioning of a medical helicopter by the military health service comprises at least 1 physician trained in emergencies and aviation constraints, and a nurse who embarks depending on the available space (aircraft type and distance). Abroad, the organization of medical aid at sea may differ. For example, in Denmark and Norway, the crew includes a doctor and a nurse trained in emergencies and aeronautical environments [1,2]. In waters adjacent to Alaska, helicopters from the United States Coast Guard are rigged by a diver-rescuer who only provides first aid [3]. The use of helicopters in medical evacuation is not without risk, though at Lanveoc, there has not been any report of serious physical injuries of the medical team. In the literature, data on the use of the helicopter on land show a significant risk of injury when compared with the road ambulance. The studies by Bledsoe and Smith [4] and Maguire et al [5] showed that air medical transport is

Table 4 Evolution of the prehospital and hospital diagnosis

responsible for 22% of deaths of Prehospital personnel in the United States, whereas it represents less than 1% of all medical transports. Grisson et al [6] emphasized on crew coordination to prevent such accidents by regular training and a briefing and debriefing of evacuations to improve both aeronautical and medical safety and efficacy.

Acute chest pain is the leading cause of evacuations related to a medical condition, with 13% of offshore emergencies managed from the Lanveoc-Poulmic Naval Air Base. On land, they represent only 4.9% of the pathologies encountered in the emergency department, behind pelvic and abdominal pain [7]. In our study, chest pain etiologies on the high seas were mainly acure coronary syndrome (ACS) (50%) and STEMI (24%). In the United Kingdom, most evacuations carried out by the Royal Air Force are emergency trauma (30.7%). Cardiac etiologies represent 7.3% of the missions conducted at sea in Scotland between 1980 and 1989 [8]. In Norway, along the Barents Sea, Haagensen et al [2] found a majority of emergency trauma. Cardiac emergencies repre- sented 12.2% of all missions, and 23.4% of all medical emergencies (behind digestive emergencies).

Our study showed a predominance of STEMI in the diagnosis of acute chest pain. This result is surprising because data from the literature concerning the general population shows a predominance of NSTEMI in the diagnosis of acute chest pain [9,10]. In contrast to ACS, Novaro et al [11] showed that NSTEMIs were more frequent among tourists of the ferry crossing along the United States. Among Cardiovascular emergencies on board, 37% were NSTEMI and 21% were STEMI.

Although the management of our patients on high seas requires the use of the helicopter, it is not totally without risk in unstable patients [12]. There is a theoretical risk, during a flight, of destabilization of cardiopathy by hypoxia second- ary to altitude and by a hyperadrenergic state associated with stress and responsible for atrial and ventricular hyperexcit- ability [13]. However, this risk is diminished in our study because the helicopters fly at low altitude (1500 ft or 450 m on average), and patients systematically benefit from oxygen therapy. Despite these theoretical risks, the literature shows

NSTEMI

Low Molecular Weight Heparin, analgesic, nitro derivative (if SBP>120mmHg, clopidogrel or prasugrel (loading dose) orally in the absence of motion sickness

O2, analgesic, nitro derivative

STEMI

Low molecular weight heparin, analgesic, nitro derivative (if SBP>120mmHg, clopidogrel or prasugrel (loading dose) orally in the absence of motion sickness Thrombolysis when primary angioplasty site >90 minutes

Dynamic ECG incompatible with acute coronary syndrome

Soft medical management

Dynamic ECG compatible with acute coronary syndrome

aggressive medical management

After winching Dynamic ECG +++

Favor IV or subcutaneous treatment

Before winching

Dynamic ECG, peripheral vein route Aspirin 250 mg IVL

Acute chest pain (regulation)

Fig. 2 Flowchart of the management of an acute chest pain in the high seas in a deteriorated aeronautical or marine situation.

no higher mortality or Cardiovascular complications in coronary patients evacuated by helicopter [14-16]. For this reason, helicopter transport should be medicalized to treat rhythmic or hemodynamic Acute complications of ACS [17]. Grine et al [18] have recently shown that medicalized helicopter transport for early revascularization by primary angioplasty does not alter the clinical benefits of the latter.

Even if the working conditions are extreme, the management of chest pain on the high seas may be optimal. The patient is conditioned with a monitoring of vital signs (heart and breathing rate, blood pressure, oximetry, temper- ature, and blood glucose), a multi-ECG, and the implemen- tation of peripheral venous catheters. The parenteral route (IV or subcutaneous) is preferred, considering the risk of motion sickness. Despite the difficult flying conditions, the pharmacopoeia of emergency cardiac treatment and moni- toring of patients allows for the safe application of current treatment recommendations.

Fibrinolysis is possible when the traumatic risk of winching is low. However, it is rare to find the right setting for thrombolysis in a medical mission (less than 3 hours from pain onset) together with satisfactory environ- mental conditions. With a hospital Transfer time of approximately 30 minutes (average time of 33 minutes in our study), the physicians should focus on primary angioplasty rather than thrombolysis.

In-flight defibrillation no longer presents restrictions in a medevac context. Dedrick et al showed that defibrillation could be performed safely when following usage pre-

cautions. Prohibited during takeoff and landing, defibrilla- tion can be done with the approval of the skipper, who must be made aware of the theoretical risks of electromagnetic interference [19].

Thus, the limits of medicalized helicopter missions are not therapeutic but diagnostic. Indeed, 42% of the initial diagnoses in our study were later corrected. In addition to the limited duration of intervention, diagnostic errors can be explained by the nuisance that being in a helicopter produces in these situations. The noise precluding auscultation, the low-intensity red lighting, the vibrations, the equipment (wetsuit), and the small space area in which to work reduce the movements’ possibilities of the caregivers.

From these findings, a reflection on the management of chest pain during these missions was conducted. A management flowchart has been proposed within the framework of the evaluation of professional practices, with a diagnostic reasoning based around the electrocardiogram and the patients’ monitoring (Fig. 2).

Conclusions

The study has highlighted the high prevalence of acute chest pain occurring in an offshore environment. These are Serious diseases predominated by acute coronary syndromes in patients with high risk. If therapeutic management is guided by recommendations, the diagnosis is difficult in a dangerous context, which makes these medicalized

evacuations singular. Intervening on the high seas on a ship is not a routine operation. It requires appropriate training, both aeronautical and in emergency practice. The medical practice in this hostile environment and within a time limit requires a plasticity of mind that it is difficult to understand in our comfortable ground emergency services.

References

1. Wegmann F, Kromann-Andersen B, Staehr Johansen T, Jessen K. Sixteen years with the Danish Search and rescue Helicopter Service. Aviat Space Environ Med 1990;61:436-9.
2. Haagensen R, Sjoborg KA, Rossing A, Ingiliae H, Markengbakken L, Steen PA. Long-range rescue helicopter missions in the Arctic. Prehosp Disaster Med 2001;121:1070-4.
3. Herrou C. US Cost Guard. Marines edition; 1997. p. 89-91.
4. Bledsoe BE, Smith MG. Medical helicopter accidents in the United States: a ten-year review. J Trauma 2004;56:1325-9.
5. Maguire BJ, Hunting KL, Smith GS, Lewick NR. Occupational fatalities in emergency medical services: a hidden crisis. Ann Emerg Med 2002;40:625-32.
6. Grisson CK, Thomas F, James B. Medical helicopters in wilderness search and rescue operations. Air Med J 2006;25:18-25.
7. Ducasse JL, Sages-Raffy C, Faber C, Dumoulin F, Houze-Cerfon V, Coulomb I. Rapport annuel sur l’activite des structures d’urgence en Midi-Pyrenees, 2008. Observatoire Regional des Urgences Midi- Pyrenees; 2009.
8. Williams MJ. A review of medical airlifts by a search rescue squadron on the east coast of England over 18 years. Arch Emerg Med 1991;8: 108-14.
9. Hasdai D, Behar S, Wallentin L, et al. A prospective survey of the characteristics, treatments and outcomes of patients with acute coronary syndromes in Europe and the Mediterranean basin. Eur Heart J 2002;23:1190-201.
10. Fox KAA, Goodman SG, Klein W, et al. Management of acute coronary syndromes. Variation in practice and outcome. Eur Heart J 2002;23:1177-89.
11. Novaro GM, Bush HSh, Fromkin KR, et al. Cardiovascular emergencies in Cruise ship passengers. Am J Cardiol 2010;105:153-7.
12. Varon J, Fromm RE, Marik P. Hearts in the air: The role of aeromedical transport. Chest 2003;124:1636-7.
13. Essebag V, Halabi AR, Churchill-Smith M, Luchmedial S. Air medical transport of cardiac patients. Chest 2003;124:1937-45.
14. Gong H. Air travel and oxygen therapy in cardiopulmonary disorders. Chest 1992;101:1104-13.
15. Bellinger R, Califf R, Mark D. Helicopter transport of patients during acute myocardial infarction. Am J Cardiol 1988;61:435-8.
16. Topol EJE, Fung AY, Kline E, et al. Safety of helicopter transport and out-of-hospital intravenous Fibrinolytic therapy in patients with evolving myocardial infarction. Catheter Cardiovasc Diagn 1986;12: 151-5.
17. Spangler D, Rogers W, Gore J, et al. Early tPA treatment and aeromedical transport of patients with acute myocardial infarction. J Interv Cardiol 1991;4:81-9.
18. Grines CL, Westerhausen DR, Grines LL, et al. A randomized trial of transfer for primary angioplasty versus on-site thrombolysis in patients with high-risk myocardial infarction: the air primary angioplasty in myocardial infarction study. J Am Coll Cardiol 2002; 39:1713-9.
19. Boissin, Hillion. Etude de la mise en place des defibrillateurs semi- automatiques dans les aeronefs de transport de l’Armee de l’Air. Rapport final. Centre d’experiences aeriennes militaires. 2004; Not published.