Medical helicopters in wilderness search and rescue operations

Characteristics and critical care interventions in drowning patients treated by the Danish Air Ambulance from 2016 to 2021: a nationwide registry-based study with 30-day follow-up

BACKGROUND

Improving oxygenation and ventilation in drowning patients early in the field is critical and may be lifesaving. The critical care interventions performed by physicians in drowning management are poorly described. The aim was to describe patient characteristics and critical care interventions with 30-day mortality as the primary outcome in drowning patients treated by the Danish Air Ambulance.

METHODS

This retrospective cohort study with 30-day follow-up identified drowning patients treated by the Danish Air Ambulance from January 1, 2016, through December 31, 2021. Drowning patients were identified using a text-search algorithm (Danish Drowning Formula) followed by manual review and validation. Operational and medical data were extracted from the Danish Air Ambulance database. Descriptive analyses were performed comparing non-fatal and fatal drowning incidents with 30-day mortality as the primary outcome.

RESULTS

Of 16,841 dispatches resulting in a patient encounter in the six years, the Danish Drowning Formula identified 138 potential drowning patients. After manual validation, 98 drowning patients were included in the analyses, and 82 completed 30-day follow-up. The prehospital and 30-day mortality rates were 33% and 67%, respectively. The National Advisory Committee for Aeronautics severity scores from 4 to 7, indicating a critical emergency, were observed in 90% of the total population. They were significantly higher in the fatal versus non-fatal group (p < 0.01). At least one critical care intervention was performed in 68% of all drowning patients, with endotracheal intubation (60%), use of an automated chest compression device (39%), and intraosseous cannulation (38%) as the most frequently performed interventions. More interventions were generally performed in the fatal group (p = 0.01), including intraosseous cannulation and automated chest compressions.

CONCLUSIONS

The Danish Air Ambulance rarely treated drowning patients, but those treated were severely ill, with a 30-day mortality rate of 67% and frequently required critical care interventions. The most frequent interventions were endotracheal intubation, automated chest compressions, and intraosseous cannulation.

First Successful Rescue of a Lost Person Using the Human Detection System: A Case Study from Beskid Niski (SE Poland)

Recent advances in search and rescue methods include the use of unmanned aerial vehicles (UAVs), to carry out aerial monitoring of terrains to spot lost individuals. To date, such searches have been conducted by human observers who view UAV-acquired videos or images. Alternatively, lost persons may be detected by automated algorithms. Although some algorithms are implemented in software to support search and rescue activities, no successful rescue case using automated human detectors has been reported on thus far in the scientific literature. This paper presents a report from a search and rescue mission carried out by Bieszczady Mountain Rescue Service near the village of Cergowa in SE Poland, where a 65-year-old man was rescued after being detected via use of SARUAV software. This software uses convolutional neural networks to automatically locate people in close-range nadir aerial images. The missing man, who suffered from Alzheimer’s disease (as well as a stroke the previous day) spent more than 24 h in open terrain. SARUAV software was allocated to support the search, and its task was to process 782 nadir and near-nadir JPG images collected during four photogrammetric flights. After 4 h 31 min of the analysis, the system successfully detected the missing person and provided his coordinates (uploading 121 photos from a flight over a lost person; image processing and verification of hits lasted 5 min 48 s). The presented case study proves that the use of an UAV assisted by SARUAV software may quicken the search mission.

Columbia Icefield Bus Rollover: A Case Study of Wilderness Mass Casualty Triage, Treatment, and Transport

Mass casualty incidents (MCIs) are rare in wilderness and mountain settings. Few case studies have reported the response of such events within jurisdictions with well-developed trauma and emergency medical services systems (EMS). Here we explore a MCI in a wilderness setting on the Columbia Icefield inside the Jasper National Park within the Canadian Rocky Mountains. An all-terrain bus was involved that had rolled over while transporting tourists to explore the glacier. The bus rolled multiple times down the slope adjacent to the road, leading to 3 deceased and 21 patients requiring transport. A massive pre-hospital response ensued.Due to the location, extreme environment, and unusual complexities, the response involved significant use of aeromedical resources, physician field deployment, and centralized coordination centers. Readers are reminded of the importance of aeromedical surge capacity in allowing for effective distribution of patients to multiple receiving facilities. Our experience aligns with and reinforces many of the recommendations for wilderness MCI management; however, future research should focus on determining optimal triage strategies for mountain MCIs. Furthermore, future research should explore optimal strategies for developing a rescue chain given the availability of mixed transport resources, as well as the role of physicians in MCI response and where they are best placed in the incident command system.

Utilizing Drones to Restore and Maintain Radio Communication During Search and Rescue Operations

INTRODUCTION

The ability of rescuers to maintain contact with incident command (IC) and each other is a critical component of search and rescue (SAR) operations. When rescuers lose radio communication with operation leaders, the effectiveness of operations may be substantially affected. This often occurs owing to the limitations of standard communications equipment in difficult terrain or when victims are beyond line-of-sight. This study investigates the viability of using an aerial drone-repeater system configuration to restore and maintain radio communications between IC and deployed rescuers.

METHODS

SAR operators in Southern Utah identified 10 areas where radio communication is compromised during live rescue operations. Trained SAR personnel were deployed to these areas in a mock exercise. After confirmed loss of communication, a repeater-equipped aerial drone was piloted 122 m above IC to restore communication. Once restored, communication was assessed at regular intervals for the duration of the mock deployment.

RESULTS

In all 10 areas tested, communication was successfully restored. In all cases, once communication was restored, no additional loss of radio contact occurred. The time between communication loss and restoration across the 10 scenarios was 6.5±1.1 (4.4-9.3) min (mean±SD with range).

CONCLUSIONS

This method of restoring radio communication among SAR personnel could drastically improve the ability to assist victims and help mitigate the risks faced by rescuers. SAR leaders should be made aware of the useful applications of drones during SAR operations, especially in instances where communication is compromised.

Challenges of helicopter mountain rescue missions by human external cargo: need for physicians onsite and comprehensive training

Background

Human external cargo (HEC) extrication during helicopter rescue missions is commonly used in mountain emergency medical services. Furthermore, longline or winch operations offer the opportunity to deliver professional medical care onsite. As the safety and quality of emergency medical care depends on training and experience, we aimed to investigate characteristics of mountain rescue missions with HEC.

Methods

We retrospectively reviewed all rescue missions conducted by Air Zermatt (a commercial rescue service in the high-alpine region of Switzerland) from January 2010 to September 2016.

Results

Out of 11,078 rescue missions 1137 (10%) required a HEC rescue. In 3% (n = 29) rapid sequence induction and endotracheal intubation, in 2% (n = 14) cardiopulmonary resuscitation, and in 0.4% (n = 3) a chest tube insertion had to be performed onsite prior to HEC extraction. The most common medical intervention onsite is analgesia or analgosedation, in 17% (n = 142) fentanyl or ketamine was used in doses of ≥ 0.2 mg or ≥ 50 mg, respectively.

Conclusions

As these interventions have to be performed in challenging terrain, with reduced personnel resources, and limited monitoring, our results point out the need for physicians onsite who are clinically experienced in these procedures and specially and intensively trained for the specific characteristics and challenges of HEC rescue missions.

Advanced airway management in hoist and longline operations in mountain HEMS - considerations in austere environments: a narrative review This review is endorsed by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM)

Background

Providing sufficient oxygenation and ventilation is of paramount importance for the survival of emergency patients. Therefore, advanced airway management is one of the core tasks for every rescue team. Endotracheal intubation is the gold standard to secure the airway in the prehospital setting. This review aims to highlight special considerations for advanced airway management preceding human external cargo (HEC) evacuations.

Methods

We systematically searched MEDLINE, EMBASE, and PubMed in August 2017 for articles on airway management and ventilation in patients before hoist or longline operation in HEMS. Relevant reference lists were hand-searched.

Results

Three articles with regard to advanced airway management and five articles concerning the epidemiology of advanced airway management in hoist or longline rescue missions were included. We found one case report regarding ventilation during hoist operations.

The exact incidence of advanced airway management before evacuation of a patient by HEC is unknown but seems to be very low (< 5%). There are several hazards which can impede mechanical ventilation of patients during HEC extractions: loss of equipment, hyperventilation, inability to ventilate and consequent hypoxia, as well as inadequacy of monitoring.

Conclusions

Advanced airway management prior to HEC operation is rarely performed. If intubation before helicopter hoist operations (HHO) and human cargo sling (HCS) extraction is considered by the rescue team, a risk/benefit analysis should be performed and a clear standard operating procedure (SOP) should be defined. Continuous and rigorous training including the whole crew is required. An international registry on airway management during HEC extraction would be desirable.

Drowning Injuries: Analysis of a Decennial Air Medical Rescue Center Experience

OBJECTIVE

Drowning is one of the leading injury death causes in younger children. Common intensive care measures seem not to improve neurologic outcome, and early prognostic options appear partially unreliable. Therefore, we evaluated a cohort of drowning patients cotreated by a helicopter emergency medical service regarding typical incident constellations, early and subsequent prognostic options, and relevant interventions.

METHODS

All patients prehospitally cotreated by helicopter emergency medical service "Christoph 4" in primary missions because of drowning incidents during a 10-year period were evaluated. Patient, prehospital, and clinical data were recorded retrospectively; correlations and prognostic values were evaluated with appropriate statistical tests.

RESULTS

Fifty-one patients were included. Various examination results (several vital, neurologic, and laboratory parameters) and sufficient prehospital first aid measures were significantly correlated with the final outcome (P < .05, respectively). Aspartate aminotransferase and alanine aminotransferase values precisely discriminated between the final outcome groups (P = .001 and area under the receiver operating characteristic curve = 1.0 in both cases).

CONCLUSION

Aspartate aminotransferase and alanine aminotransferase values were the most useful predictors of outcome in our study. Sufficient prehospital first aid measures were correlated with improved outcome. Regular first aider training is recommended.

Wilderness medicine

BACKGROUND

Human activity in wilderness areas has increased globally in recent decades, leading to increased risk of injury and illness. Wilderness medicine has developed in response to both need and interest.

METHODS

The field of wilderness medicine encompasses many areas of interest. Some focus on special circumstances (such as avalanches) while others have a broader scope (such as trauma care). Several core areas of key interest within wilderness medicine are discussed in this study.

RESULTS

Wilderness medicine is characterized by remote and improvised care of patients with routine or exotic illnesses or trauma, limited resources and manpower, and delayed evacuation to definitive care. Wilderness medicine is developing rapidly and draws from the breadth of medical and surgical subspecialties as well as the technical fields of mountaineering, climbing, and diving. Research, epidemiology, and evidence-based guidelines are evolving. A hallmark of this field is injury prevention and risk mitigation. The range of topics encompasses high-altitude cerebral edema, decompression sickness, snake envenomation, lightning injury, extremity trauma, and gastroenteritis. Several professional societies, academic fellowships, and training organizations offer education and resources for laypeople and health care professionals.

CONCLUSIONS

THE FUTURE OF WILDERNESS MEDICINE IS UNFOLDING ON MULTIPLE FRONTS: education, research, training, technology, communications, and environment. Although wilderness medicine research is technically difficult to perform, it is essential to deepening our understanding of the contribution of specific techniques in achieving improvements in clinical outcomes.

A 10-year analysis of 214 HEMS backcountry hoist rescues

BACKGROUND

Few published studies on civilian helicopter emergency medical services (HEMS) hoist programs exist. This study provides a demographic analysis of hoist rescue operations performed by the only FAA Part 135 hoist-approved civilian HEMS operator in the United States.

METHODS

All persons hoisted between May 29, 2001, and May 28, 2011, were retrospectively analyzed.

RESULTS

Over a 10-year period, 212 of 214 victims were hoisted. The most common indications were fall injuries (38%) and being stranded (21%). Victim demographics showed an average age of 35 ± 17years, predominantly male (79%), often associated with trauma (66%), with a majority (68%) of all victims requiring subsequent transport to a hospital by ground ambulance (24%) or flown by Life Flight (44%). Hoists occurred most often in the afternoon (14:07 ± 3:47 hours), during the weekend (53%), in the months of May-September (71%), at an altitude of 7,488 ± 1487 feet, with the seat harness (39%) being the most common mode of victim extraction. Hoist insertion of search and rescue (SAR) personnel occurred infrequently (5%).

CONCLUSION

The results from this demographic study on hoist operations can provide important demographic information for HEMS contemplating backcountry hoist operations and programs that interface with SAR agencies.

Emergency medical helicopter operations for avalanche accidents

BACKGROUND

In the European Alps emergency medical helicopter services are regularly involved in avalanche rescue missions. How the helicopter emergency medical system best supports avalanche rescue missions is controversial.

AIM OF THE STUDY

To study advantages and limitations of the early dispatch of emergency medical helicopters after avalanche accidents.

METHODS

Data on rescue mission characteristics and patterns and severity of medical emergencies were obtained for 221 helicopter avalanche rescue missions performed in the Austrian province of Tyrol between October 2008 and June 2011.

RESULTS

A buried avalanche victim had to be searched for in only 12 (5.5%) of the 221 rescue missions, whereas medical emergencies were encountered at the scene in 24 missions (11%). Survival rate for totally buried victims extricated after helicopter arrival was significantly lower than for victims extricated before helicopter arrival (19% versus 74%, p=0.0002). In 124 missions (56%) no victim was present at the scene when the helicopter arrived. Medical emergencies involved normothermic cardiac arrest (n=11), severe accidental hypothermia (n=6), critical trauma (n=7) and hypothermia combined with critical trauma (n=1). Survival rate at hospital discharge was 27% for arrested normothermic patients and 50% for trauma and hypothermia patients.

CONCLUSIONS

Medical emergencies are encountered at avalanche scenes twice as often as there is need to search for totally buried victims, clearly supporting the immediate dispatch of medical crew members to the accident site. The high rate of emergency medical helicopter operations to avalanche incidents where no victim is injured or buried may be characteristic for densely populated mountainous regions and can be reduced by a restrictive dispatch policy after avalanche accidents without clear information about human involvement.

Helicopter rescue operations involving winching of an emergency physician

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.

Factors impacting on the activation and approach times of helicopter emergency medical services in four Alpine countries

Background

The outcome of severely injured or ill patients can be time dependent. Short activation and approach times for emergency medical service (EMS) units are widely recognized to be important quality indicators. The use of a helicopter emergency medical service (HEMS) can significantly shorten rescue missions especially in mountainous areas. We aimed to analyze the HEMS characteristics that influence the activation and approach times.

Methods

In a multi-centre retrospective study, we analyzed 6121 rescue missions from nine HEMS bases situated in mountainous regions of four European countries.

Results

We found large differences in mean activation and approach times among HEMS bases. The shortest mean activation time was 2.9 minutes; the longest 17.0 minutes. The shortest mean approach time was 10.4 minutes; the longest 45.0 minutes. Short times are linked (p < 0.001) to the following conditions: helicopter operator is not state owned; HEMS is integrated in EMS; all crew members are at the same location; doctors come from state or private health institutions; organization performing HEMS is privately owned; helicopters are only for HEMS; operation area is around 10.000 km2; HEMS activation is by a dispatching centre of regional government who is in charge of making decisions; there is only one intermediator in the emergency call; helicopter is equipped with hoist or fixed line; HEMS has more than one base with helicopters, and one team per base; closest neighboring base is 90 km away; HEMS is about 20 years old and has more than 650 missions per year; and modern helicopters are used.

Conclusions

An improvement in HEMS activation and approach times is possible. We found 17 factors associated with shorter times.

Medical standards for mountain rescue operations using helicopters: official consensus recommendations of the International Commission for Mountain Emergency Medicine (ICAR MEDCOM)

The purpose of this article is to establish medical recommendations for safe and effective Helicopter Emergency Medical Systems (HEMS) in countries with a dedicated mountain rescue service. A nonsystematic search was undertaken and a consensus among members of International Commission for Mountain Emergency Medicine (ICAR Medcom) was reached. For the severely injured or ill patient, survival depends on approach time and quality of medical treatment by high-level providers. Helicopters can provide significant shortening of the times involved in mountain rescue. Safety is of utmost importance and everything possible should be done to minimize risk. Even in the mountainous environment, the patient should be reached as quickly as possible (optimally<20 min) and provided with on-site and en-route medical treatment according to international standards. The HEMS unit should be integrated into the Emergency Medical System of the region. All dispatchers should be aware of the specific problems encountered in mountainous areas. The nearest qualified HEMS team to the incident site, regardless of administrative boundaries, should be dispatched. The 'air rescue optimal crew' concept with its flexibility and adaptability of crewmembers ensures that all HEMS tasks can be performed. The helicopter and all equipment should be appropriate for the conditions and specific for mountain related emergencies. These recommendations, agreed by ICAR Medcom, establish recommendations for safe and effective HEMS in mountain rescue.

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

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.

Wilderness communications

When an emergency situation arises in a remote location, the ability to communicate with outside sources of assistance can prove very valuable. This article reviews the different types of communications technologies available to individuals in remote locations, including satellite telephones, personal locator beacons, satellite messengers, cellular telephones, and the different licensed and non-licensed 2-way radio services available for personal use. It also discusses basic radio communications techniques, emergency communication, requesting ground or air casualty evacuation, and selecting communications devices for different applications.

Web-based media for landing zone safety instruction

INTRODUCTION

Crew safety is paramount to successful helicopter emergency medical service transport. This study assesses using an online video to teach landing zone safety.

METHODS

This is a randomized, prospective study using a 5-minute video to teach landing zone safety. A pre- and post-test were used to assess efficacy of the initial instruction and subsequent knowledge decay. Block randomization by EMS agency or fire department assigned participants to 0, 2, 4, or 6-month post-video testing.

RESULTS

257 participants, including 62 EMTs, 114 firefighters, and 80 EMT/firefighters, were enrolled and randomized to immediate (A), 2-month (B), 4-month (C), and 6-month (D) post-video testing. 184 (71.6%) completed the study: A – 72 (93.5%), B – 27 (55.1%), C – 32 (64.0%), and D – 53 (65.4%). Mean scores (pre-test, post-test) were: A – (82.7%, 94.9%), B – (81.9%, 91.2%), C – (86.3%, 88%), and D – (82.6%, 92.2%). Statistically significant score increases were seen in groups A (11.1%, 95% CI 6.0%, 16.1%), B (9.0%, 95% CI 3.1%, 14.9%), and D (9.9%, 95% CI 5.3%, 14.5%). Group C had a mean increase of 2.3%, but this was not statistically significant (p = 0.41).

CONCLUSION

Web-based media is an effective means of teaching landing zone safety to first responders with minimal knowledge decay.

[Acute heart disease in search and rescue helicopter missions, from French Navy. A retrospective study from 2000 to 2007]

BACKGROUND

Search and rescue helicopters from the French navy conduct ambulance and search and rescue missions near the western coast of the French Britain. The team on board includes military doctor and paramedic. Operations in this area are challenging due to long distances and severe weather conditions.

METHODS

We studied retrospectively 205 search and rescue missions from 2000 to 2007 with special emphasis on acute heart disease and operative conditions.

RESULTS

12.2% of the missions (25/205) concern acute heart disease dominated by myocardial infarction elevation myocardial infarction. All of the patients are male. Most of them are seafarers and the others come from ferries with a median age of 53.4 years. Sixty-two percent of the missions were carried in darkness. The median range is about 80 nautical miles. Two patients died during search and rescue missions. All patient are hospitalized.

CONCLUSION

Ambulance and search and rescue mission near the western coasting of the French Britain are a challenge. Using a heavy helicopter from French Navy was the best way to carry medical treatment to seafarers and passengers of ferries suffering from acute heart disease.