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CHAPTER 3:  Air Medical Transport      9 proximally on the pelvis. The padded proximal end of the Hare ® splint abuts the ischial tuberosity (Figure 2-5). The proximal end of the Sager® splint rests against the pubic symphysis (Figure 2-6). These splints cannot be used if a pelvic fracture is suspected because the pressure on the pelvis may further displace a fracture and cause more bleeding. Also, do not apply a traction splint if there is open fracture, hip dislocation, suspicion for neurovascular injury to the extremity, or injury about the knee, because a traction splint may exacerbate neurovascular or knee injury. (See Video: Hare Traction Splint.) Leg traction splints also may be used for tibial shaft fractures. Traction splints should not be used for fractures near the knee because longitudinal traction may damage neurovascular structures in the popliteal region. Traction splints for the tibia should be reserved for angulated or dis placed fractures; otherwise, an air splint or a pillow splint would suffice. At the scene, clothing should be removed and the extremity assessed for injury and distal neurovascular function. If the Hare ® splint is used, the proximal half ring is placed in the crease of the buttocks against the ischial tuberosity. Traction is placed on the ankle with the padded ankle strap by one rescuer while the splint is strapped to the leg. The ankle strap is then attached to a ratcheting mechanism, and traction is tight ened. If a Sager ® splint is used, the splint is placed on the medial side of the limb up against the groin. The padded ankle hitch is applied, and traction is applied until malalignment is reduced and pain is relieved. Elastic straps are then applied to hold the splint to the leg. The Hare ® splint can be longer than an ambulance cot when fully extended, and care needs to be taken when closing the rear door of the ambulance. The Sager ® splint is shorter than the Hare ® splint, and one Sager® splint can be used to splint both legs simultaneously. The Sager ® FIGURE 2-5. Hare® traction splint. (Courtesy of Jan Smith, RN, MPH, NREMT-P; acknowledgments to Kara Smith and Lucky Bruton, EMT-P.) FIGURE 2-6. Sager Emergency Traction Splint; Model S304, Form III Bilateral, Application  step  3  “Secure.”  [Used  with  permission  from:  Minto  Research  &  Development,  Inc., Redding, CA.] splint is less bulky and therefore takes up less room in an ambulance or a helicopter.  PELVIC STABILIZERS Unstable pelvic fractures can be immobilized to minimize the risk of bleeding from patient movement and during transport. 75 A sheet wrap, applied around the patient at the level of the trochanter and fastened with a clamp or hemostat, is the simplest stabilization method. Com mercial devices, such as the SAM Pelvic Sling ®, are also available.  PHARMACEUTICAL SUPPLIES The basic emergency medical technician curriculum has modules that teach emergency medical technicians to administer a patient’s personal medication in specific circumstances. For example, modules are provided for administering nitroglycerin for chest pain, inhaled β-agonists for bronchospasm, glucagon for hypoglycemia, and epinephrine-preloaded injections for anaphylaxis. Some states have gone beyond this and allow BLS services to stock and provide the medications covered in these modules.

For example, modules are provided for administering nitroglycerin for chest pain, inhaled β-agonists for bronchospasm, glucagon for hypoglycemia, and epinephrine-preloaded injections for anaphylaxis. Some states have gone beyond this and allow BLS services to stock and provide the medications covered in these modules. The medications carried by ALS services are more extensive, but prehospital pharmaceutical interventions are limited to the few that make a real difference before or during transport. 76,77 These include oxygen, glucose, nitroglycerin, inhaled β-agonists, naloxone, parenteral narcotic and nonsteroidal analgesics, benzodiazepines, furosemide, epinephrine, lidocaine, magnesium, amiodarone, adenosine, diltiazem, calcium, and sodium bicarbonate. In the system that provides rapid-sequence intubation, neuromuscular junction–blocking agents (succinylcholine, vecuronium) are also provided. REFERENCES The complete reference list is available online at www.TintinalliEM.com. Air Medical Transport Keith C. Stone Stephen H. Thomas INTRODUCTION Air medical transport consists of helicopter (or rotor-wing) and airplane (or fixed-wing) transport and is an important component of EMS sys tems for prehospital care and interfacility transport. These specialized vehicles offer fast speeds, ranging from 100 to 200 miles per hour for helicopters to >500 miles per hour for airplanes. Although many ill and injured patients can be transported safely by ground, air medical trans port provides added medical assessment and care capabilities beyond those of the paramedic-staffed ground ambulance. Guidelines for the use of air medical transport exist, but field EMS personnel and physi cians involved in transfer decision making should be able to consider situational circumstances to determine the appropriate transportation mode. Weather can be an operational limitation, particularly for helicopters. The radius of service differs between helicopters and fixed-wing craft, but, as a general rule, fixed-wing transport is considered when weather conditions are poor or when transport distances exceed 150 to 200 miles. The complexity of air transport far exceeds the simple act of loading a patient on an airborne vehicle. National organizations such as the Air Medical Physician Association, the Committee on Accreditation of Medical Transport Systems, and the National Association of EMS Physicians have published texts, position statements, and guidelines covering aspects of air medical transport. The Air Medical Physician Association CHAPTER Tintinalli_Sec01_p0001-0018.indd 9 7/31/19 6:43 PM

n Association, the Committee on Accreditation of Medical Transport Systems, and the National Association of EMS Physicians have published texts, position statements, and guidelines covering aspects of air medical transport. The Air Medical Physician Association CHAPTER Tintinalli_Sec01_p0001-0018.indd 9 7/31/19 6:43 PM 10 SECTION 1: Prehospital Care  AIR MEDICAL CREW The primary considerations regarding medical members of the flight crew are crew configuration and training. Although there are few abso lutes with regard to optimal configuration, initial and recurrent training is at least as important as the credentials of the flight team members. The air medical team can have multiple compositions: nurse– paramedic, nurse–nurse, nurse–physician, or nurse–respiratory therapist. These differences may be one reason that the literature has failed to answer definitively the seemingly simple question of whether a physician should be on board the helicopter. Most U.S. programs agree that physicians are not a necessary component of helicopter EMS crews, and a recent survey showed that 92% of programs use nurse–paramedic crews. The capabilities of most U.S. nonphysician crews represent an extended scope of practice. For instance, flight paramedics and/or nurses frequently are credentialed to perform such procedures as neuromus cular blockade–assisted endotracheal intubation and cricothyrotomy. This example of extended practice scope is important, given the impor tance of prehospital airway considerations and the fact that flight crews represent a highly trained group with particular expertise in this area. Reported success rates for nonphysicians are as high as 94.6% for drugassisted and 97.7% for rapid sequence intubation–assisted endotracheal intubation and 90.9% for surgical cricothyrotomy. At this time, the best recommendation with regard to crew configu ration is for programs to continue to do what works for them, as the literature does not report the superiority of a particular model. Most U.S. programs perform a variety of scene and interfacility missions for trauma and nontrauma indications, so the nurse–paramedic configuration, combining the complementary skills of prehospital and hospitalbased practitioners, meets their needs. Some transport population heterogeneity can be addressed by the accommodation of extra crew members (e.g., neonatal nurses, intra-aortic balloon pump technicians) when logistics allow. Regardless of the background of the air medical crew, initial and recurrent training in both cognitive and procedural skills is necessary to ensure an optimal level of care.  ENVIRONMENTAL FACTORS OF AIR TRANSPORT Patient care in any transport vehicle differs from that provided while the patient is on a hospital stretcher. Vehicle vibrations, bumpy rides, noise, physiologic stress, ergonomic constraints (Figure 3-1), and motion sickness are among the factors that can affect monitoring and interventions. The impact of most vehicle-related issues in helicopter EMS can be eliminated, or at least reduced. Some solutions are easy (e.g., visual rather than aural alarms on ventilators), but flight crews must learn to “work around” other limitations (e.g., perform preflight intubation FIGURE 3-1. The patient care compartment in a Dauphin II helicopter. (http://www.ampa.org) Air Medical Physician Handbook is a particularly helpful resource for medical issues. The Committee on Accreditation of Medical Transport Systems (http://www.camts.org) accreditation stan dards address medical, aviation, organizational, and operational issues.

mpartment in a Dauphin II helicopter. (http://www.ampa.org) Air Medical Physician Handbook is a particularly helpful resource for medical issues. The Committee on Accreditation of Medical Transport Systems (http://www.camts.org) accreditation stan dards address medical, aviation, organizational, and operational issues. The National Association of EMS Physicians (http://www.naemsp.org) has created detailed position statements and guidelines addressing helicopter EMS trauma and nontrauma triage criteria, as well as training of physicians involved as air medical crew or medical directors. Rigorous training programs, covering both cognitive and procedural skills, enable flight crews to provide a high level of intratrans port care . In-flight communications capabilities should include the ability of the air medical crew to speak with medical control physicians, as well as arrange for any change of plan (e.g., direct transport to the operating suite) necessitated by patient condition. HELICOPTER TRANSPORT  AVIATION ISSUES Individual hospitals, hospital systems, or private for-profit enterprises run most U.S. civilian air transport programs. Because helicopters are expensive (ranging from $750,000 to more than $5 million each) and other aviation needs (e.g., maintenance, pilot training) are also resource intensive, most hospital-based programs lease their helicopters from vendors. The air medical program typically provides and equips com munications and medical personnel, whereas the aircraft vendor sup plies the helicopters, pilots, and maintenance personnel. Although costs vary depending on geographic region, patient case mix, equipment and aircraft used, and even the methods used for their calculation, annual operating costs for a rotor-wing service typically exceed $2 million. Safety is an overriding consideration for air transport. Optimization of safety begins well before an actual air transport, with training of the flight crew and of those who interact with them at scenes and hospitals. Training is especially important for scene responses, in which the helicopter may be landing in an unknown area with more nearby obstacles (e.g., wires, trees) than the hospital helipad. In addition to providing training for referring agencies, helicopter EMS pilots and medical crew should undergo both initial and recurrent safety training. For added protection, most helicopter EMS programs have followed the lessons of the military experience and adopted injury-prevention maneuvers such as the use of helmets and fire-resistant clothing. As another safety issue, the pilot should be “blinded” to the nature of the call during mission planning; this eliminates the introduction of acuityrelated subjectivity as the pilot considers whether the mission should be accepted. Safety is partially behind the transition of helicopter EMS programs from single-engine helicopters with visual flight rules capability to twinengine helicopters that can fly under instrument flight rules conditions. The latter aircraft have greater lifting capacity, range, and speed and usually can execute controlled landings in the event of failure of one engine. A visual flight rules aircraft can fly only during good visibility, whereas instrument flight rules aircraft operate safely in poorer conditions; both comply with visibility limitations imposed by the Federal Aviation Administration, but the instrument flight rules helicopter has fewer restrictions. If the pilot unexpectedly encounters bad weather during a flight, an instrument flight rules helicopter (as compared with a visual flight rules aircraft) has a better chance of completing the mission successfully and safely.

ral Aviation Administration, but the instrument flight rules helicopter has fewer restrictions. If the pilot unexpectedly encounters bad weather during a flight, an instrument flight rules helicopter (as compared with a visual flight rules aircraft) has a better chance of completing the mission successfully and safely. Due to the complexity of instrument flight rules operations, some programs (especially those with frequent bad weather periods) have elected to use two-pilot instrument flight rules. Air medical programs operate under rules established by the national aviation authority—in the United States, the Federal Aviation Adminis tration. Additionally, the industry itself has set forth stringent standards under the auspices of the Committee on Accreditation of Medical Transport Systems. On request, the Committee on Accreditation of Medical Transport Systems performs site visits of air medical programs to certify that they comply with strict safety and operational (as well as clinical) standards. As of September 2016, 183 U.S. transport programs were accredited by the Committee on Accreditation of Medical Transport Systems. Tintinalli_Sec01_p0001-0018.indd 10 7/31/19 6:43 PM

rforms site visits of air medical programs to certify that they comply with strict safety and operational (as well as clinical) standards. As of September 2016, 183 U.S. transport programs were accredited by the Committee on Accreditation of Medical Transport Systems. Tintinalli_Sec01_p0001-0018.indd 10 7/31/19 6:43 PM CHAPTER 3:  Air Medical Transport      11 on patients who appear likely to deteriorate). Some problems will be specific to a service’s particular aircraft, mission profile, or crew back ground. Individual program patient care protocols should take into account the service’s equipment and personnel-related capabilities and limitations. One transport-related issue that cannot be avoided is the question of altitude and its potential effects on the patient and the crew. In fact, altitude considerations vary with location—a Denver-based program has concerns that are different from those of a Miami service. Envi ronmental conditions also have an impact on altitude considerations, because aircraft operating under instrument flight rules frequently fly at higher altitudes than those operating under visual flight rules. Of course, fixed-wing transports have more pronounced altitude considerations. Helicopter (or fixed-wing) altitude and environment have potential effects on patient pathology as well as the crew’s ability to monitor and care for the patient. Helicopters generally transport patients at about 1000 to 3500 ft above ground level (not necessarily sea level), although sometimes these altitudes are increased for instrument flight rules flights or for clearing of obstacles or terrain. Therefore, altitude-related problems such as hypoxemia, dehydration, and low temperature tend to be mild or relatively easily to overcome. However, geographic differ ences are important. Some western U.S. programs fly with supplemental oxygen for the medical crews. Pressure-related problems related to Boyle’s law (the volume of a gas increases when the pressure decreases at a constant temperature) may represent the most important consideration for helicopter-transported patients. For example, even the relatively low transport altitude range for helicopter EMS may affect patients with certain diagnoses (e.g., decompression sickness, cerebral arterial gas embolism) or instrumen tation (e.g., tamponading devices for esophageal variceal hemorrhage). Endotracheal intracuff pressures increase an average of 33.9 cm of water at a mean altitude of 2260 ft. 3 This could raise the cuff pressure above the perfusion pressure of the tracheal mucosa, leading to injury. Hand-held commercially available devices can be used to keep cuff pressure within the target range of 20 to 30 cm of water. The devices are held in one hand and connected to the cuff inflation port. An inflation bulb can be used to further inflate the cuff, or an air-release button can be used to remove air while the cuff pressure is simultaneously measured by the device. In some cases, an understanding of altitude issues is important in preventing complications. To minimize aspiration risk, gastric intuba tion should be performed for unconscious patients transported by air. Alternatively, understanding of the relevant science can be used to prevent overreaction to potential barometric risks. For example, not all patients with small pneumothoraces who do not otherwise require tube thoracostomy require pretransport chest decompression simply because they are to be transported by air. CLINICAL USE OF HELICOPTERS While trauma still constitutes the majority of helicopter transports for most programs, as more time-critical treatments develop, more transports will be arranged for noninjured patients .

thoracostomy require pretransport chest decompression simply because they are to be transported by air. CLINICAL USE OF HELICOPTERS While trauma still constitutes the majority of helicopter transports for most programs, as more time-critical treatments develop, more transports will be arranged for noninjured patients . There are many schemes (age group, scene/interfacility mission type) for categorization of helicopter EMS transports, but the simplest categorization is into trauma and nontrauma. Logistical issues are important to both categories. Therefore, these are considered first.  LOGISTICS AND HELICOPTER EMS USE Some logistic prompts for helicopter consideration include (1) lengthy transport time for ground ambulances to reach the tertiary center, (2) ground vehicle transport time to the local hospital exceeds the time required for helicopter transport to the tertiary center, and (3) for entrapped trauma patients, extrication time is expected to exceed 20 minutes. In some cases, helicopter EMS is used because local ground EMS personnel lack the expertise to provide the indicated level of intratransport care. Another important consideration is whether a region’s ground EMS system can provide transport to the receiving tertiary center while maintaining the ability to cover its base area with appro priate advanced life support care. Questions that can assist healthcare providers in determining the appropriate transport modality for an individual patient are listed in Table 3-1.  HELICOPTER EMS FOR TRAUMA PATIENTS There is one group of trauma patients—those in traumatic cardiac arrest—for whom air medical scene response has shown a very low rate of resuscitation and essentially zero survival. 4 Most helicopter EMS programs have their crews accompany traumatic arrest patients by ground to the nearest facility. After the initial triage response decision, the larger issue is whether helicopter EMS actually improves outcome for any injured patients . There is disagreement over this question, but multiple studies have shown improved outcomes. 5-8 The recent largest study to demonstrate improved outcomes after traumatic injury related to helicopter transport analyzed 223,475 patients from the National Trauma Data Bank transported by helicopter (28%) or ground EMS (72%). For trauma patients who were admitted to level I or level II centers, patients transported by helicopter had a significantly improved survival to hospital discharge compared with patients transported by ground transport. 5 Another recent study of 14,440 trauma patients taken to a level I trauma center demonstrated that patients transported by helicopter had a reduced overall mortality and that patients transported by all other means were more likely to die in the ED. The outcomes of rural trauma patients are thought to be worse than those of urban trauma victims. After controlling for age, gender, and Injury Severity Score, a Utah study 9 of helicopter transports from rural and urban trauma scenes found no difference in mortality. This study demonstrated that the helicopter scene transport of rural trauma victims appears to be a mortality equalizer. A shortcoming of the literature is that studies generally address only the hard end point of mortality, with little emphasis on either mecha nisms for survival improvement or nonmortality end points. Regardless of these shortcomings, the primary issue for trauma helicopter EMS is not whether some patients benefit, but rather how well those patients most likely to benefit from helicopter use can be identified by improved triage criteria. Although definitive criteria are lacking, the National Association of EMS Physicians has published guidelines for clinical situations that are appropriate for air transport (Table 3-2).

benefit, but rather how well those patients most likely to benefit from helicopter use can be identified by improved triage criteria. Although definitive criteria are lacking, the National Association of EMS Physicians has published guidelines for clinical situations that are appropriate for air transport (Table 3-2).  HELICOPTER EMS FOR NONTRAUMA PATIENTS The reason that helicopter EMS trauma literature is (relatively) abun dant is that there are ready means for controlling for the differing acu ities of air- and ground-transported patients. Unfortunately, there is no such easy methodology for patients with nontrauma diagnoses, and acuity scales for nontrauma patients generally have not been accepted for use in assessing the association between transport mode and outcome. Some general guidelines are available (Table 3-3), and the logistic considerations noted previously apply to nontrauma flights. In most helicopter EMS programs, the largest single nontrauma diagnostic category is cardiac. Patients in cardiac arrest should be transported to the nearest hospital rather than loaded on an aircraft. Transport for TABLE 3-1 Questions to Aid in Determining Need for Helicopter Transport •   Is minimization of time spent out of hospital important? •   Is time-sensitive evaluation and treatment involved, and is it available at the referring facility? •   Is the patient inaccessible to ground transport? •   What are the transport route weather conditions? •   Does the weight of the patient preclude air medical transport? •   Are aircraft landing facilities available at or near the referring hospital? •   Is critical-care life support required that is not available with ground transport? •   Would ground transport leave the local area without adequate EMS coverage? •   If local ground transport is not an option, are regional ground critical-care transport services available? Tintinalli_Sec01_p0001-0018.indd 11 7/31/19 6:43 PM

tical-care life support required that is not available with ground transport? •   Would ground transport leave the local area without adequate EMS coverage? •   If local ground transport is not an option, are regional ground critical-care transport services available? Tintinalli_Sec01_p0001-0018.indd 11 7/31/19 6:43 PM 12 SECTION 1: Prehospital Care TABLE 3-2 Air Transport Indications for Scene Trauma General and mechanism of injury •  Trauma  score <12 •  Unstable  vital signs •  Significant  trauma in patients age <12 or >55 y and pregnant patients •  Multisystem  injuries •  Ejection  from vehicle •  Pedestrian  or cyclist struck •  Death  in same passenger compartment •  Penetrating  trauma of the head, neck, chest, abdomen, or pelvis •  Crush  injury of the head, chest, or abdomen •  Fall  from height •  Near  drowning Neurologic injuries •  Glasgow  Coma Scale score <10 •  Mental  status deterioration •  Obvious  skull fracture •  Spinal  cord injury Thoracic injury •  Major  chest wall injury (e.g., flail chest) •  Pneumothorax •  Hemothorax •  Suspected  cardiac injury Abdominal/pelvic injuries •  Significant  abdominal pain after injury •  Seatbelt  sign or abdominal contusion •  Rib  fractures below the nipple line •  Unstable  pelvis •  Open  pelvic fracture •  Pelvic  fracture with hypotension Orthopedic injuries •  Amputation  of limb (partial or complete) •  Finger  or thumb amputation when replantation is available •  Fracture/dislocation  with associated vascular compromise •  Limb  ischemia •  Open  long-bone fractures •  Two  or more long-bone fractures Thermal injury •  Burns  of >20% body surface area •  Burns  of face, head, hands, feet, or genitalia •  Inhalation  injury •  Chemical  or electrical burns •  Burns  associated with other traumatic injuries TABLE 3-3 Air Transport Indications for Nontrauma Conditions Cardiac •  Acute  coronary syndromes •  Cardiogenic  shock •  Cardiac  tamponade •  Mechanical  cardiac disease (cardiac rupture) Critically ill medical or surgical patients •  Pretransport  cardiac arrest •  Pretransport  respiratory arrest •  Mechanical  ventricular assist •  Continuous  vasoactive medications •  Risk  of airway deterioration •  Severe  poisoning •  Need  for hyperbaric oxygen treatment •  Emergent  dialysis •  Unstable  GI bleeding •  Surgical  emergencies (e.g., aortic dissection) Obstetric •   Delivery  will require  obstetric  or neonatal  care beyond  the capabilities  of the referring  facility •   Active premature labor <34 wk or estimated fetal weight <2000 grams •   Acute abdominal emergencies <34 wk or estimated fetal weight <2000 grams •   Preeclampsia or eclampsia •   Third-trimester hemorrhage •   Fetal hydrops •   Complicated maternal medical conditions •   Predicted severe fetal heart disease Neurologic •   CNS hemorrhage •   Spinal cord compression •   Status epilepticus Neonatal •   Gestational age <30 wk or fetal weight <2000 grams •   Supplemental oxygen exceeding 60%, continuous positive airway pressure, or mechanical ventilation •   Extrapulmonary air leak, interstitial emphysema, or pneumothorax •   Medical emergencies (e.g., congestive heart failure, disseminated intravascular coagulation) •   Surgical emergencies (e.g., diaphragmatic hernia, necrotizing enterocolitis) primary or rescue coronary intervention for ST-segment elevation myocardial infarction is a frequent indication for helicopter use and can be done rapidly and safely. 10,11 Cardiac patients with pacemakers or those who have received thrombolytic therapy can be transported safely and effectively by helicopter EMS. Another growing indication is the provision of lytic therapy or vas cular intervention for ischemic stroke.

ndication for helicopter use and can be done rapidly and safely. 10,11 Cardiac patients with pacemakers or those who have received thrombolytic therapy can be transported safely and effectively by helicopter EMS. Another growing indication is the provision of lytic therapy or vas cular intervention for ischemic stroke. 12 The American Stroke Associa tion (http://www.strokeassociation.org) Task Force on Development of Stroke Systems 13 identified helicopter EMS as an important part of stroke systems. However, a study of 122 patients transported to a stroke center after receiving recombinant tissue plasminogen activator at the referring hospital demonstrated no benefit in patient outcomes in airtransported patients. Obstetric transports are a special consideration for air transport because many high-risk patients are best delivered at tertiary care cen ters. The question for this population is primarily one of safety during transport. In-flight deliveries are a major resuscitation problem for both mother and infant. Experience has provided some reassurance that the use of helicopter EMS to transport high-risk obstetric patients did not result in deliveries in the back of the helicopter, and neonatal outcomes are not adversely impacted by transport. FIXED-WING AIR MEDICAL TRANSPORT Fixed-wing aircraft can serve a wide variety of missions, from urgent to routine, over great distances. Because airplanes land only at airports, they cannot respond to the scene, and fixed-wing transports need ground ambulance connections at both ends of the flight to transport the patient between the hospital and airport. Because of these factors, fixed-wing flights generally take longer to arrange and are uncommonly used for truly emergent patients. Helicopters are virtually always dedicated as air medical transport vehicles when used by U.S. EMS services, but fixed-wing airplanes used for medical transport may have other roles. When fixed-wing aircraft are used for air medical transport, cabins must be reconfigured. Ven dors have developed removable medical equipment modules that can be placed relatively quickly in the aircraft cabin. Tintinalli_Sec01_p0001-0018.indd 12 7/31/19 6:43 PM