Air Ambulance: Effects of Industry Changes on Services Are Unclear
Released: 2010-09-30T00:00:00

Letter

Background

Air ambulances can play an important role in transporting patients with time critical injuries and conditions to medical facilities and providing patients with advanced care while en route. Air ambulances transported more than 270,000 patients in 2008, and their use is widely believed to improve the chances of survival for trauma victims and other critical patients. Composing more than 80 percent of air ambulance aircraft, helicopter air ambulances transport patients from the scene of an accident to a hospital or perform short-distance interhospital patient transfers. Because fixed-wing aircraft only fly between airports, they are not typically used to transport injured patients from an accident scene. Patients are transported by ground to and from the airport. Fixed-wing air ambulances generally perform more long-distance interhospital transports, often moving patients from a hospital to a distant specialized facility. Just over half of air ambulance transports are for moving patients between hospital facilities, one-third are for transporting victims from the accident scene to a hospital, and the remainder are for other purposes, such as organ transports or specialty care flights such as for pediatric and neonatal patients.

Most air ambulances carry a pilot and a two-person medical crew. The medical crew may include a physician, nurse, paramedic, emergency medical technician, or other medical personnel. According to AAMS, the typical medical crew includes a critical care nurse and a paramedic. A critical care nurse has specialized training in responding to life-threatening health problems, such as those faced by many patients who are transported on air ambulances. Paramedics represent the highest licensure level of prehospital emergency care in most states, as they have enhanced skills and can administer a range of medications and interventions. Other caregivers and physicians may be added to a medical crew if the patient’s condition necessitates further care.

Air Ambulance Providers Operate Under Three Basic Business Models

In the air ambulance industry, the business model is generally defined by the entity that owns or contracts for the aviation and medical services that are provided. Air ambulance providers generally use one of the following three business models.

Hospital-based: a hospital generally controls the business by providing medical services and staff while usually contracting out for the aviation component, including the pilots, mechanics, and aircraft.

Independent: operations are not controlled or run by a specific medical facility. Independent providers may directly employ, or can contract for, the medical and flight crews to provide air ambulance services.

Government operator: a state or local government or military unit owns and operates the air ambulances.

However, a large number of variations exist within these structures. Some providers have adopted a “hybrid” model or have established joint ventures with hospitals.

Air Ambulance Providers Receive Revenue from a Variety of Sources, Including Federal Medicare and Medicaid Programs

Air ambulance companies receive payment for transports from several sources, including private health insurance, government programs such as Medicare and Medicaid, and the patient. While industry revenue and payment data are not widely available, we obtained data on the percentage of total income that four air ambulance providers receive from each source. (See fig. 1.) For these four companies, private insurance companies or Medicare paid for most of the transport costs. A relatively small percentage of the costs were paid for by the patient themselves.

From 2002 through 2006, the Centers for Medicare and Medicaid Services, the agency within the Department of Health and Human Services that administers Medicare and Medicaid, phased in a national fee schedule for air ambulance providers as a part of a series of Medicare payment reforms that Congress mandated in 1997. The national fee schedule redistributed, on a budget-neutral bases, payments among various types of ambulance services. Prior to 2002, Medicare reimbursement differed depending on the air ambulance provider’s business model: hospital-based providers were reimbursed based on reasonable costs, while independent providers were reimbursed based on reasonable charges. This policy contributed to wide variation in the reimbursement rate for the same service, with hospital- based providers generally receiving higher reimbursement than independent providers for similar services. The new national fee schedule established one payment rate for fixed-wing transports and another rate for helicopter transports. The fee schedule also provides higher reimbursement for transports in rural areas, but it does not differentiate payments according to the business model followed, the size of the aircraft used, or the level of medical or safety equipment on board.

In addition to the revenue they receive from transports, air ambulance providers may receive or generate income for their operations from other sources. For example, hospital-based providers may receive funding from the hospital, and some independent air ambulance providers have established membership programs that generate income from annual fees. Government operators may receive funding through taxes or surcharges. For example, Maryland’s government-operated air ambulance service receives funding through a surcharge on state motor vehicle registrations.

The Air Ambulance Industry Has Seen Growth and Structural Change, but Perspectives Differ on Implications for Availability, Efficient Use, Safety, and Services Provided

From 1999 through 2008, the number of patients transported by helicopter air ambulances increased from just over 200,000 to over 270,000, or about 35 percent, and the number of air ambulance helicopters increased from 360 to 677, or by about 88 percent. The data also show that between 2007 and 2008 there were an increasing number of helicopter air ambulances and a decreasing number of transports. (See fig. 2.) We were unable to determine whether the downward movement in 2008 represents a trend because 2009 data on patients transported were not available.

The number of air ambulance helicopters varies widely by state. (See fig. 3.) Most states have multiple helicopters based in their state. Vermont and Rhode Island have none, but their air transport needs are served by providers in bordering states.

Since 1999, the structure of the air ambulance industry has also changed. In the past, most air ambulance providers were hospital-based, whereas today, about half the providers are independent, with no support from hospitals in terms of ownership, risk, and financial support.

According to industry stakeholders, a variety of factors contributed to the industry’s growth and structural change. The downsizing or closing of some community hospitals, according to stakeholders, resulted in longer transports to get some patients to hospitals, making it more advantageous to use air ambulances that could transport patients over longer distances more quickly than by ground ambulances. Similarly, the establishment of regional medical facilities, such as cardiac and stroke centers that provide highly specialized care for critically ill patients, encouraged the use of air ambulances, again because they could transport patients more quickly from outlying areas. Finally, implementation of the Medicare fee schedule provided those wishing to provide air ambulance services a degree of predictability for Medicare reimbursement, which stakeholders noted enabled air ambulance providers to develop more accurate financial plans.

Growth in the Number of Air Ambulances and Movement of Their Bases into Communities Have Increased Availability

The growth in the number of helicopters and their movement into communities have generally made them more available to those in need. According to some stakeholders, having multiple air ambulances in an area increases the industry’s capacity to meet regional needs. For example, if one helicopter is unavailable because it is undergoing scheduled maintenance or responding to an air medical transport request, another helicopter in the same region is more likely to be available. Additionally, with more air ambulances available in rural communities, rural ground ambulances may be involved less frequently in transporting patients over long distances, and rural communities are less likely to be left without an ambulance or EMS crew.

Providers also relocated air ambulance bases, moving them from hospitals into surrounding communities and thereby extending their availability. (See fig. 4.) A 2005 nationwide study of access to trauma centers in the United States found that 84 percent of the population had access to a Level I or II trauma center within 60 minutes. Of that population, almost 28 percent could only access those trauma centers in an hour or less because they were located within the coverage of an air ambulance. Stakeholders concerned with the growth in the industry, noted that the increase in the number of helicopters has been focused in areas that already have multiple air ambulance services while rural areas remain underserved. They said that ensuring the availability of air ambulance services in rural areas is problematic because covering a large, sparsely populated geographic area affects profitability and impacts companies’ ability to provide services in these areas.

Literature Indicates That Questions about the Medical Necessity of Some Air Ambulance Transports Have Existed for Decades

Stakeholders concerned with industry growth believe that uncontrolled growth of air ambulances in a region leads to medically unnecessary use— that is, when an air ambulance is dispatched for a patient whose injury or illness is not severe enough for the patient to need air transport. One stakeholder group compared data on the severity of patients’ injuries and discharge rates, developed by Arizona’s Department of Health Services, with similar data for a Level I Trauma Center in New Hampshire, and an air ambulance service in Boston. According to their analysis, the injuries of patients transported in Arizona, a state with a comparatively large number of helicopters, were less severe than those of patients transported in the two other states that have fewer helicopters. However, the comparison does not examine other factors involved in decisions about how to transport patients, including transport distances, who makes the transport decision, and what protocols guide the decision maker. Additionally, the decision to request an air ambulance is generally made by the attending physician at a hospital or by first responders at an accident scene.

Concerns about medically unnecessary use of air ambulances have existed since the early 1980s. We identified 32 studies examining triage criteria using data collected from as early as 1975 to as recently as 2008. Fifteen study authors conclude that further measurement indices are needed to better identify over- and undertriage of patients transported by air ambulance. Because triage protocols and patterns of air ambulance utilization have changed considerably in the past 30 years, early reports must be interpreted with caution and their relevance to current triage protocols and air ambulance is unclear. It is also important to consider these studies in their historical context. Numerous guidelines on appropriate use of ambulances have been published. In 2006, the American College of Emergency Physicians and the National Association of EMS Physicians (NAEMSP) issued Guidelines for Air Medical Dispatch that built upon earlier guidelines published by NAEMSP, AAMS, and the American Academy of Pediatrics. The 2006 position statement recognized the continuing debate surrounding air medical transport and noted that research regarding the appropriate deployment of complex medical care systems was in its infancy. Furthermore, the position statement noted that many EMS systems have their own criteria for air medical dispatch, which usually differ between regions based on demographic, geographic, and health care resource considerations.

Work on developing national guidelines is under way. After its February 2009 air ambulance safety public hearing, NTSB recommended that the Federal Interagency Committee on Emergency Medical Services develop national guidelines for selecting the most appropriate emergency transportation mode for urgent care. In response, the committee has begun to develop guidelines for the emergency transport of trauma victims from the scene of injury. These guidelines may eventually include recommendations for the transport of patients with other medical emergencies and for interfacility transports.

Little Evidence Exists to Link Industry Growth to Safety Concerns

Proponents of increasing state regulatory authority argue that having multiple providers in the same area creates pressure to fly that can lead to a number of unsafe practices. They maintain that providers’ high fixed costs create economic pressure to fly, and the concentration of many air ambulances in a geographic area further exacerbates this pressure. Air ambulance providers’ fixed costs can amount for up to 80 percent of a provider’s total costs. The air ambulance itself can cost from $600,000 to $12 million when outfitted with varying levels of flight and medical equipment.

Participants at NTSB’s February 2009 public hearing discussed potential safety concerns with helicopter shopping. Helicopter shopping refers to the practice of calling, in sequence, various providers until a provider agrees to take a flight assignment. Stakeholders who support the existing regulatory and oversight framework noted that there are situations where calling additional providers is an appropriate and safe use of resources. (See table 1.)

Having information on prior turndowns or aborted missions could help a provider decide whether it is safe to fly. FAA has provided state EMS officials with a sample letter that could be given to dispatchers within their state that outlines sample communications policies, including policies on disclosing information about prior turndowns. However, even with information on prior turndowns, pilots are responsible for checking weather conditions and determining if the conditions meet FAA’s requirements for flying. NASEMSO representatives suggested that the time spent sequentially calling additional air ambulance providers consumes time during which a patient could be en route to a trauma center via ground ambulance.

Call jumping occurs when a provider sends an air ambulance to an accident scene without a request. If another air ambulance provider is also responding based on a request from first responders, there is a heightened risk of collision. Stakeholders who advocate for an increase in state regulatory authority maintain that, like helicopter shopping, call jumping can result from economic pressure to fly. However, some instances perceived as call jumping may stem from a lack of communication among first responders. (See table 2.)

To minimize the risk of two helicopters responding based on separate requests from first responders, states can establish communication and coordination protocols to be followed at the more than 6,000 public safety answering points, or 911 call centers, nationwide. These centers provide the opportunity to coordinate air ambulance requests and avoid dispatching two air ambulances to the same crash scene. However, these centers are locally based and operated, and their structure varies widely.

Beyond anecdotes, we found little evidence of helicopter shopping resulting in unsafe flights or of call jumping. We identified FAA’s Aviation Safety Reporting System (ASRS) as a potential source for such information. As a voluntary reporting system, ASRS contains reporting biases reflecting that not all participants in the aviation system are equally aware of ASRS or equally willing to file reports. Consequently, ASRS statistics represent a conservative measure of the number of such events that are occurring. In our review of 464 air ambulance reports submitted to ASRS over 15 years, we found 2 that contained information about call jumping and none that described instances of helicopter shopping. These data could indicate that helicopter shopping and call jumping occur infrequently. On the other hand, these practices may be underreported if air ambulance crews are unaware that they can report safety issues to ASRS.

During the summer of 2010, the Center for Leadership, Innovation and Research in EMS established the EMS Voluntary Event Notification Tool (EVENT)—an anonymous, non-punitive and confidential web-based system that allows anyone in the United States or Canada to report an event or action that leads to or has the potential to lead to a worsened patient outcome. Reports received in EVENT are sent to the EMS governing body of the state, territory or province responsible for the EMS system in which the event occurred. Once the governing body receives the anonymous notification, they would be encouraged to address systemic issues in order to improve the overall quality of care provided. As of September 1, 2010, EVENT had received one report. While it is too early to evaluate the impact of the EVENT reporting system, it appears to be a positive step that could provide useful data for state regulators.

FAA is in the process of addressing several NTSB recommendations related to safety issues that NTSB has made regarding helicopter air ambulance safety. FAA officials expect to release a notice of proposed rulemaking in the fall of 2010 that would address issues such as additional safety equipment requirements, minimum acceptable weather conditions, use of risk management practices, and additional training requirements.

Perspectives Differ on the Impact of Cost-Related Business Decisions on the Services Provided in Air Ambulances

Stakeholders concerned with the growth of the industry assert that economic pressures have led some air ambulance providers to cut costs by using smaller, less expensive helicopters and less experienced medical crews. In particular, they point to the use of small, single-engine helicopters instead of twin-engine helicopters. According to these stakeholders, larger helicopters allow access to the patient’s entire body, while the smaller helicopters that some providers use restrict medical access to the full body of the patient. However, single-engine helicopters are not always smaller than twin-engine helicopters.

During our site visits, we observed how patients were transported in one particular single-engine helicopter. We also saw that medical personnel had access to the patient’s upper body, which facilitates airway management, an important component of prehospital care. (See fig. 5.) The patient’s lower body is situated next to the pilot with a transparent barrier separating the patient and the pilot. A senior official at that provider agreed that the space inside the helicopter is limited but said the helicopter meets the medical needs of most patients. However, there are differing perspectives in the industry about the need to have access to a patient’s entire body during transport.

Stakeholders concerned with growth in the industry told us that small helicopters generally lack climate control, which results in temperatures in the aircraft that may be either too cold or too hot. According to an experienced emergency medical technician-paramedic, air that is too cold has a bad effect on trauma patients, while air that is too hot has a bad effect on cardiac patients. Stakeholders who favor the existing regulatory and oversight framework point out that the need for climate control might vary depending on the region in which the air ambulance operates. An air ambulance provider that operates in a southern climate may not need a heater, while one that operates in a northern climate may not need an air conditioner. One provider we visited that generally operates smaller helicopters told us that all of its 87 aircraft have heaters and are being outfitted with air conditioning as they undergo refurbishment. We were told that physicians and hospitals can exercise some degree of control over helicopter characteristics. For example, we were told that the requesting physician sometimes requires that an air ambulance have climate control when it is necessary for the medical care of the patient in interfacility transfers. One stakeholder we spoke with commented that physicians are often unaware that air ambulances may lack climate control and would therefore not be inclined to ask about it. According to a senior DOT official, the department was exploring whether regulation of climate control in air ambulance helicopters is under federal or state jurisdiction.

Stakeholders concerned with the growth in the industry also argue that, to save on costs, some providers are hiring less experienced medical crews, which they maintain degrade patient services. We were unable to validate this argument through our literature synthesis. We identified seven studies on the impact of a medical crew’s composition—whether, for example, the crew consists of a physician and a nurse or a nurse and a paramedic—but there was no consensus on how the composition of the medical crew influences a patient’s outcome. We also found three studies examining the impact of crew composition on transport time, and all three studies found that crew composition had no impact on transport time. We found no studies examining the impact of a medical crew’s experience on patient outcomes.

Evidence Lacking to Suggest Recent Growth Has Affected Medical Outcomes from Air Transports

Several of the concerns raised by stakeholders within the air ambulance community appear to be outcomes of industry growth and competition. For example, concerns about helicopter shopping or call jumping might arise if providers are competing to gain business. Similarly, concerns about migration toward single-engine aircraft or reductions in the qualifications of medical staff might arise as companies seek to cut costs to improve profitability. The pressure of competing for business and working to obtain maximum efficiency through cost containment arises in nearly all business endeavors. These forces are usually good for consumers because they lead to efficiency, lower prices, and service offerings better tailored to the needs and desires of consumers. However, health care markets have some imperfections and these forces might work differently in these markets. For example, health care consumers may lack information about their diagnoses, treatment needs, the quality of different providers, as well as the prices charged by different providers. Additionally, health insurance can affect consumer’s ability or inclination to make informed health care choices. Air medical patients have limited influence on air medical markets and are not typically making the choice in terms of mode of transport or provider.

For air ambulance services, medical outcomes are a critical measure of quality. Through our research, we identified numerous articles documenting rigorous research on various aspects of air ambulances, but very few shed light on the effect of the growth of the industry. For example, we found no studies that compare patient outcomes between states that have multiple providers in the same region, and states with fewer providers. Consequently, we were unable to draw definitive conclusions to support or refute many of the allegations that have been raised. DOT’s General Counsel and National Highway Traffic Safety Administration officials agreed that more data on many aspects of air ambulance operations would enlighten the debate about providing states greater regulatory authority over air ambulances. While there was consensus among the stakeholders in the industry that there is a lack of data about potential concerns, ACCT stated that the debate about the extent of state regulatory authority of air ambulances is fundamentally one of philosophical differences about the government’s role in controlling public services, such as emergency medical services.

Federal and State Courts and DOT Have Clarified Some Boundaries of Federal and State Regulation of Air Ambulances, but Questions Remain

Because air ambulances have both an aviation component, regulated by the FAA, and a medical component, regulated by the states, the boundaries of federal and state regulation have come under question. The aviation components include the aircraft itself, including its airworthiness and safety, as well as the personnel who maintain and pilot the aircraft, communicate with ground personnel, and monitor flight instruments, while medical personnel attend to the health of the patient on board. (See fig 6.) These safety components are under the jurisdiction of FAA, which administers federal aviation regulations that govern safety and operational requirements, nationwide. Hence, the industry is subject to FAA safety regulations covering areas such as pilot training requirements, flight equipment, and aircraft configuration. The medical component, on the other hand, is under state regulatory authority. DOT opinion letters and federal and state court decisions have affirmed that states have the authority to enact and enforce requirements for medical services delivered to patients in air ambulances and for the medical staffing, personnel, and equipment used to deliver those services. States also have the authority to develop training on how to use an aircraft or equipment so as to ensure proper patient care. For example, such training might focus on how pressurization in the aircraft cabin affects specific medical conditions.

As noted earlier, some stakeholders favor changing the regulatory and oversight framework so that states would have a stronger role in regulating the nature and scope of services that an air ambulance provider must offer. For example, state EMS officials believe that they should be able to determine the appropriate number of air ambulances serving a particular area and set additional standards in terms of equipment used and services provided, as they currently do for other parts of the EMS system. However, strengthening the states’ role would require federal legislation to alter the Airline Deregulation Act (ADA) of 1978 that deregulated the air carrier industry. Court decisions subsequent to the passage of the ADA determined that air ambulances were air carriers as defined by the ADA. In enacting the ADA, Congress determined that “maximum reliance on competitive market forces” would best further “efficiency, innovation, and low prices” as well as “variety quality ... of air transportation.” One ADA provision, designed to phase out state governments’ economic control over the industry, explicitly precludes state regulation of matters related to air carrier rates, routes, and services. Courts have ruled that this provision preempts states from acting in some regulatory areas, such as requiring prospective air ambulance providers to obtain a certificate of need based on the state’s assessment of the population to be served and the potential for unnecessary duplication of services.

Over the past two decades, federal and state courts, and DOT, through opinion letters issued by its Office of General Counsel, have affirmed these authorities and have determined the specific issues that states can and can not regulate. (See table 3.) Dating as far back as 1986, courts have ruled that state certificate of need laws are unenforceable because they conflict with the ADA by limiting the number of air ambulance services doing business within the state. DOT, responding to numerous inquiries from state Attorneys General and private industry, has advised that certificate of need provisions and similar “public convenience and necessity” provisions are expressly preempted by the ADA because the states are attempting to regulate in the area of price, routes, and services. Most recently and prominently, a federal district court in North Carolina found that the state’s certificate of need requirement was preempted by ADA. These rulings are limited to specific states.

Stakeholders concerned with the growth in the industry generally support a stronger role for states in regulating the air ambulance industry. They believe that many of the court rulings and DOT opinions diminish states’ ability to oversee patient care and safety. For example, DOT, in a letter to an attorney in the state of Hawaii, wrote that states cannot require, through regulation, that air ambulance providers operate on a 24/7 basis on the grounds that such a requirement constitutes economic regulation. These stakeholders view a requirement for air ambulances to operate on a 24/7 basis as a patient care issue that states should be able to control. DOT further stated in its letter that states could contract with air ambulance providers for these services. Under such circumstances, the states would be functioning as customers rather than regulators, and therefore not be subject to federal preemption of state regulation. In commenting on a draft of this report, ACCT and NASEMSO stated that contracting for air ambulance services in this manner is not a realistic option for states because of fiscal resource limitations. (See app. III for a complete description of significant federal and state court cases and DOT and state attorneys general opinions.) it is possible that a state medical program, ostensibly dealing with only medical equipment/supplies aboard aircraft, could be so pervasive or so constructed as to be indirectly regulating in the pre-empted economic area of air ambulance prices, routes or services.

Stakeholders have expressed concern that the open-ended nature of this statement allows any medical regulation to be challenged as an economic regulation and thus be preempted under the ADA. However, it is important to note that DOT did not find that any specific “medical” regulation was preempted under this reasoning and has not yet found that any state regulation to date falls within this category.

Stakeholders have raised concerns that there is no regulation at either the federal or state level to protect the public from the economic consequences of air ambulance practices. These stakeholders also expressed concerns about areas of state regulation that create uncertainty because DOT and the federal and state courts have yet to rule on them, such as a requirement for climate control on air ambulances. Uncertainty about how the courts would rule has led to calls for a federal legislative solution that would spell out federal and state authorities. Several federal legislative proposals seek to clarify the states’ role in regulating medical issues and to allow the states to institute certain types of economic regulation for air ambulances, including certificate of need requirements, by carving out an exception to the ADA’s preemption of state regulation of prices, routes, and services. However, the current scheme of regulation of air ambulances has been in place since 1978 and has generated four significant court decisions that, for the most part, have addressed fact- specific questions about the relationship between federal and state authority to oversee and regulate the industry. DOT has stated that the continued use of case-by-case departmental determinations can still clarify the appropriate role of states in regulating air ambulance services. DOT officials told us that states should address their uncertainties to DOT, and the department is more than willing to respond with an opinion based on the facts and circumstances presented. However, it appears that states have not fully utilized this option. Since 1986, DOT has issued only eight opinion letters in response to inquiries on the limits of federal and state authority over air ambulances. Stakeholders favoring increased state regulatory authority have expressed concerns with continuance of this case-by-case approach, stating that it results in piecemeal guidance, inconsistency, and confusion.

DOT officials have also raised concerns that allowing states to exert authority, in this case in the economic area, could create a patchwork of state regulation disrupting what has been, until now, a fairly well- understood set of uniform rules. Moreover, DOT, along with the Federal Trade Commission and the Department of Justice, have expressed concern that state authority to implement certificate of need laws could be used to limit market entry for air ambulances and reduce competition in the air ambulance industry—an outcome Congress sought to avoid when enacting the ADA.

Agency and External Comments and Our Evaluation

We provided a draft of this report to the Departments of Transportation (DOT) and Health and Human Services (HHS), and the National Transportation Safety Board (NTSB) for comment. We also invited representatives from the Association of Air Medical Services (AAMS), the Association for Critical Care Transport (ACCT), the Air Medical Operators Association (AMOA) and the National Association of State EMS Officials (NASEMSO) to review a draft of this report and provide comments. There was a consensus among the reviewers that there is a lack of data about the air ambulance industry and a recognition that the study had to rely on available data and information, which we obtained by conducting a comprehensive review of the existing subject area literature and recording stakeholder comments and opinions. Further, this lack of empirical evidence limited our ability to determine the full impact of changes in the industry. Our research of the air ambulance industry and discussions with stakeholders within the industry identified two distinct perspectives about the impact of the changes. To the extent that data or other information was available, we provided it to inform these perspectives. Where data or other information did not exist, we clearly attributed statements and identified the perspective of the stakeholders making the comment.

DOT’s Office of General Counsel and HHS provided technical comments that we incorporated as appropriate. NHTSA, within DOT, provided detailed comments that we also incorporated as appropriate. NTSB transmitted written comments to us in a letter. (See app. IV). NTSB’s statement in its letter that GAO was asked to “review the U.S. air ambulance industry to determine if changes in oversight authority are needed” is not accurate. As stated in the report, the objectives of our work were to examine how the air ambulance industry had changed over the last decade and the implications of these changes, as well as to examine the relationship between the federal and state oversight and regulation of the industry. While our report contains information that may be used when considering whether changes in oversight authority for the air ambulance industry may be needed, we were not asked to determine if changes are needed and thus do not address this question in our report. NTSB identified three issues that it believed should be discussed in more detail in our report. First, NTSB noted that the draft should have addressed in greater detail that competition in the air ambulance industry is restricted because of fixed fee reimbursements by payers (private insurers, Medicare, and Medicaid) for air ambulance services and the industry’s limited capacity to adjust prices. While Medicare and Medicaid reimbursement rates are fixed, private sector prices are not. As is the case with most health care services, air ambulance providers generally negotiate prices with insurance companies. NTSB further noted that such restricted competition could be linked to safety concerns. Following the Board’s February 2009 public hearing on air ambulance helicopter safety, NTSB issued several safety recommendations, including one to HHS to determine if reimbursement rates should differ according to the level of air ambulance transport safety provided. In response, HHS stated that it did not believe that payment should vary based on the level of transport safety provided but that all air ambulance operators should meet minimum FAA safety standards. Second, NTSB also noted said that the draft did not clearly state whether there is evidence that helicopter shopping and call jumping occur, and if so, to what extent. In response, we clarified that beyond anecdotes, we found little evidence of helicopter shopping resulting in unsafe flights or of call jumping. NTSB additionally raised questions about our use of ASRS as a source of information regarding the prevalence of these practices. We agree that ASRS has limitations, and opted to include it in the report because it is one of the few available data sources with information applicable to the industry. We added additional information in the report about the limitations and potential under- reporting. Finally, NTSB noted that it would be helpful to know if there is evidence to support the belief that the use of air ambulances improves the chances of survival for trauma victims and other critical patients. It was not our objective to determine if air ambulance transport is beneficial and we did not do the research necessary to comment on the validity of the belief.

AAMS provided technical comments which we incorporated where appropriate. Comments provided by ACCT, AMOA, and NASEMSO were generally reflective of their views regarding the implications of the changes in the air ambulance industry and the role of states in regulating the industry. We incorporated their comments throughout the report as appropriate.

We are sending copies of this report to the appropriate congressional committees, DOT, the Department of Health and Human Services, NTSB, and other interested parties. The report also is available at no charge on the GAO Web site at http://www.gao.gov.

If you or your staff members have any questions about this report, please contact me at (202) 512-2834 or dillinghamg@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made major contributions to this report are listed in appendix IV.

Appendix I: Scope and Methods

The scope of our review was the structure and practices of the air ambulance industry in the United States, and framework for overseeing and regulating U.S. air ambulance services.

To determine how the U.S. air ambulance industry changed from 1999 through 2008, we obtained and analyzed available data that provided information on the growth and evolution of the industry, including shifts in business models, and the types of air ambulance aircraft that are used to provide services. Specifically, we reviewed and analyzed data compiled by Ira Blumen, MD. Dr. Blumen is the Medical/Program Director, University of Chicago Aeromedical Network. His database on the air ambulance industry extends back to 1980 and includes the number of helicopter air ambulances used in the industry and the number patients transported. We also reviewed and analyzed the data contained in the Atlas and Database of Air Medical Services (ADAMS) and interviewed a senior official at the Calspan-University of Buffalo Research Center (CUBRC), the research organization that maintains and publishes the database in partnership with the Association of Air Medical Services (AAMS). ADAMS has been annually updated since 2004 and serves as a centralized source of information on air medical service providers, including the number and location of air ambulance helicopter bases. ADAMS began including data for fixed-wing air ambulances in 2007. At our request, CUBRC also provided us with an update of the types of helicopters used in the air ambulance industry. We also obtained and analyzed data on Medicare payments to air ambulance providers from the Centers for Medicare and Medicaid, the agency within the Department of Health and Human Services that administers the Medicare and Medicaid programs. Additionally we reached out to more than 400 air ambulance providers, industry associations, and state Emergency Medical Services officials asking that they provide us any data, information, published or unpublished reports, papers, articles, or other potentially relevant sources of information of which they would like us to be aware. To determine how the industry has evolved, we examined industry, National Transportation Safety Board, and stakeholder documents. To determine the implications of these changes for the availability of services, efficient use of air ambulance resources, safety, and services provided, we undertook an extensive literature synthesis covering over 250 articles describing scholarly research that produced quantitative results. For more detailed information on the literature synthesis, see appendix II. We attended two semiannual meetings of the Federal Interagency Committee on Emergency Medical Services. We also reviewed previous GAO reports; Federal Aviation Administration (FAA) documents; the transcript of a 2009 National Transportation Safety Board’s (NTSB) hearing on helicopter emergency medical services and the board’s recommendation letters; a congressional hearing transcript; and congressional testimonies, reports, and position papers published by AAMS and other stakeholder associations; and published documents of the Foundation for Air-Medical Research and Education, and the Flight Safety Foundation. In addition, we conducted interviews with representatives of AAMS; industry stakeholders who favor changing the regulatory and oversight framework, including representatives of the Association for Critical Care Transport (the leading proponent of change in the regulatory and oversight framework) and industry stakeholders who oppose changing the regulatory and oversight framework, including representatives of the Air Medical Operators Association (the key industry group favoring the existing regulatory and oversight framework). We also conducted four site visits to air ambulance providers that reflected differing geographic locations, business models, and opinions about regulatory structure. Specifically, we observed operations at a government-provided air ambulance service operated by Maryland State Police, a hospital-based air ambulance service in the mid- Atlantic region (MedStar Transport) and independent providers headquartered in Missouri (Air Evac Lifeteam) and Maine (LifeFlight of Maine). Air Evac LifeTeam’s management favors the existing regulatory structure, while LifeFlight of Maine’s management advocates increased state regulation of the air ambulance industry. We also met with representatives of Dartmouth-Hitchcock Advanced Response Team, which is a hospital-based provider, and Boston Medflight, which is consortium- owned.

To determine the relationship between federal and state oversight and regulation of the air ambulance industry, we reviewed federal aviation laws, and the Airline Deregulation Act (ADA) of 1978, and challenges to state authority to regulate in matters that are federally preempted under these acts. We also reviewed Department of Transportation (DOT) General Counsel letters and state attorneys general opinion letters to state officials or attorneys. We discussed these letters, which interpret provisions of the ADA, with DOT General Counsel officials. We also discussed the implications of industry trends and federal and state regulatory authority with the key industry stakeholders mentioned above, as well as with officials at the Federal Aviation Administration (FAA); the National Highway Traffic Safety Administration; NTSB; and representatives of the National Association of State Emergency Medical Services Officials. We also received briefings and reviewed documents provided by proponents and opponents of increased state regulation.

Appendix II: Literature Synthesis

Step 1. Literature search

To identify and evaluate literature and studies that contain empirical data related to the air ambulance industry, we conducted a literature synthesis. Our objective was to identify any studies with empirical data related to air ambulance availability, services provided in the air ambulance, competition, and cost. We initially searched for articles published in the preceding 5 years, from January 2005 to January 2010. The search focused on the safety, cost, quality, and oversight of air ambulance services, including studies and articles that addressed the issues of helicopter shopping and call jumping. The search statements included a variety of terms to capture materials that examined these issues. We queried various bibliographic research databases including ProQuest, AcademicOneFile, MEDLINE, Dialog Transportation and Transportation Business, Electronic Collections Online, Nexis for scholarly and trade literature, Congressional Research Service, Congressional Budget Office, GAO, Government Printing Office, National Technical Information Service databases for publications produced by or funded by the federal government, PolicyFile, and WorldCat for government publications and literature that is not published commercially or is not generally accessible.

The results of this search, combined with articles obtained through discussions with stakeholders in the air ambulance industry, Internet searches, and our review of air ambulance-related Web sites, yielded 36 relevant studies.

As the job progressed, and the dearth of quantifiable data became evident, we expanded our search criteria to include all articles published between January 1, 2000, and May 2010, which contained empirically derived results. We determined that this time frame would include studies performed prior to the proliferation of helicopters in the air ambulance industry that started occurring around 2002-2003. In this search, we looked at air ambulances in a broader context and aimed to be more comprehensive than in previous searches. Search statements relied primarily on subject terms (when available) for air ambulances and similar concepts and did not include any other search terms as modifiers. The databases searched were Nexis Statistical Master File, ProQuest, Academic OneFile, GAO, MEDLINE, Biosis, SciSearch, Cumulative Index to Nursing and Allied Health Literature, EMBASE, PASCAL, Gale Group Health and WellnessDatabase, National Technical Information Service, TRIS, Government Printing Office, Electronic Collections Online, and Ovid.

The librarian reviewed the search results and removed duplicate citations, foreign air ambulance service, military based, or medical procedure studies, and nonrelevant articles. A total of 641 citations were sent to the team for review.

Step 2. Abstract review

The team reviewed all the titles sent by the librarian. Articles with no abstract were excluded due to lack of empirical findings, high probability of article pertaining to current events, or an editorial commentary of current policy issues. For articles with abstracts, two team members independently reviewed the abstract to determine if the article addressed the previously identified topics and appeared to contain empirical data. If both reviewers agreed that the article was relevant or not relevant, the article was saved or rejected accordingly. When the reviewers disagreed, a third team member reviewed the abstract and made the final decision. The team requested that the librarians obtain complete copies of all saved, relevant articles. This process yielded 91 relevant studies.

Step 3. Synthesis

All relevant full text studies underwent three reviews—first by an analyst who synthesized the study, second an initial review by a methodologist, and the third and final review by a second methodologist. The methodologists determined whether the research was sufficiently rigorous to support the stated conclusions. Articles that were not based on U.S. populations or did not include empirical data were excluded. Relevant articles were summarized in a synthesis document that captured the title, authors, setting, sponsor of the research, methods, findings and conclusions, and limitations.

Step 4. Bibliography review

The team reviewed the bibliography for relevant articles synthesized in step 3 to identify additional potentially relevant articles. The team then selected articles from the bibliographies that appeared relevant and were (1) in English, (2) not based on a foreign population, (3) not international studies, and (4) not military studies. For articles that met these criteria, the team attempted to obtain the abstracts from the National Institute of Health’s, National Library of Medicine PubMed database (http://www.ncbi.nlm.nih.gov/pubmed).

The team then repeated the abstract review, synthesis, and bibliography review process one additional time (see fig. 7).

Step 5. Analysis

With a methodologist’s help, the team analyzed and aggregated the synthesized articles to develop narratives describing the findings of the literature.

Appendix III: Key Court Cases and Opinion Letters from DOT or State Attorneys General

Table 4 summarizes key court cases related to the air ambulance industry. Table 5 summarizes DOT or state Attorneys General Opinions related to the air ambulance industry.

Appendix IV: Comments from the National Transportation Safety Board

Appendix V: GAO Contact and Staff Acknowledgments

GAO Contact

Staff Acknowledgments

In addition to the contact named above, Maria Edelstein, Assistant Director; Edmond Menoche, Senior Analyst; Amy Abramowitz; Heather Bartholomew; Owen Bruce; Christine Brudevold; Leia Dickerson; Leslie Gordon; David Hooper; Karla Lopez; Ashley McCall; Sara Ann Moessbauer; Cynthia Saunders; and Kristin VanWychen made key contributions to this report.

Bibliography

Arfken, C.L., M.J. Shapiro, P.Q. Bessey, and B. Littenberg. “Effectiveness of Helicopter Versus Ground Ambulance Services for Interfacility Transfer.” The Journal of Trauma, Injury, Infection, and Critical Care vol. 45, no. 4 (1998): 785.

Baack, B.R., E.C. Smoot, J.O. Kucan, L. Riseman, and J.F. Noak. “Helicopter Transport of the Patient with Acute Burns.” The Journal of Burn Care & Rehabilitation vol. 12 no. 3(1991): 229-233, http://www.ncbi.nlm.nih.gov/pubmed/1885639.

Baxt, W.G. and P. Moody. “The Impact of Advanced Prehospital Emergency Care on the Mortality of Severely Brain-Injured Patients.” The Journal of Trauma vol. 27 no. 4 (1987): 365-369, http://www.ncbi.nlm.nih.gov/pubmed/3573084.

Baxt, W.G. and P. Moody. “The Impact of Rotorcraft Aeromedical Emergency Care Service on Mortality.” JAMA: The Journal of American Medical Association vol. 249 no. 22 (1983): 3,047-3,051.

Baxt, W. G. and P. Moody. “The Impact of a Physician as Part of the Aeromedical Prehospital Team in Patients with Blunt Trauma.” JAMA: The Journal of the American Medical Association vol. 257 no. 23 (1987): 3,246-3,250.

Benson, N.H., R.L. Alson, E.G. Norton, A.P. Beauchamp, R. Weber, and J.L. Carreras. “Air Medical Transport Utilization Review in North Carolina.” Prehospital and Disaster Medicine vol. 8 no. 2 (1993): 133-137.

Berns, K.S., J.J. Caniglia, D.G. Hankins, and S.P. Zietlow. “Use of the Autolaunch Method of Dispatching a Helicopter.” Air Medical Journal vol. 22 no. 3 (2003): 35-41.

Bledsoe, B.E., A.K. Wesley, M. Eckstein, T.M. Dunn, and M.F. O’Keefe. “Helicopter Scene Transport of Trauma Patients with Nonlife-Threatening Injuries: A Meta-Analysis.” Journal of Trauma-Injury Infection and Critical Care vol. 60 no. 6 (2006): 1,257-1,265.

Boyd, C.R., K. Corse, and R.C. Campbell. “Emergency Interhospital Transport of the Major Trauma Patient: Air Versus Ground.” Journal of Trauma vol. 29 no. 6 (1989): 789-793.

Branas, C.C., E.J. MacKenzie, J.C. Williams, H.M. Teeter, M.C. Flanigan, A.J. Blatt and C.S. ReVelle. “Access to Trauma Centers in the United States.” JAMA: Journal of American Medical Association vol. 293 no. 21 (2005): 2,626-2,633.

Brathwaite, C.E., M. Rosko, R. McDowell, J. Gallegher, J. Proenca, and M.A. Spott. “A Critical Analysis of on-Scene Helicopter Transport on Survival in a Statewide Trauma System.” Journal of Trauma vol. 45 no. 1(1998): 140-144.

Burney, R.E., D. Hubert, L. Passini, and R. Maio. “Variation in Air Medical Outcomes by Crew Composition: A Two-Year Follow-Up.” Annals of Emergency Medicine vol. 25 no. 2 (1995): 187-192.

Burney, R.E., L. Passini, D. Hubert, and R. Maio. “Comparison of Aeromedical Crew Performance by Patient Severity and Outcome.” Annals of Emergency Medicine vol. 21 no. 4 (1992): 375-378.

Burney, R.E., K.J. Rhee, R.G. Cornell, M. Bowman, D. Storer, and J. Moylan. “Evaluation of Hospital-Based Aeromedical Transport Programs using Therapeutic Intervention Scoring.” Aviation, Space, and Environmental Medicine vol. 59 no. 6 (1988): 563-566, http://www.ncbi.nlm.nih.gov/pubmed/3390116.

Carr, B.G., J.M. Caplan, J.P. Pryor, and C.C. Branas. “A Meta-Analysis of Prehospital Care Times for Trauma.” Prehospital Emergency Care vol. 10 no. 2 (2006): 198-206.

Celli, P., A. Fruin, and L. Cervoni. “Severe Head Trauma: Review of the Factors Influencing the Prognosis.” Minerva Chirurgica vol. 52 no. 12 (1997): 1,467-1,480.

Chappell, V.L., W.J. Mileski, S.E. Wolf, and D.C. Gore. “Impact of Discontinuing a Hospital-Based Air Ambulance Service on Trauma Patient Outcomes.” Journal of Trauma vol. 52 no. 3 (2002): 486-491.

Cocanour, C.S., R.P. Fischer, and C.M. Ursic. “Are Scene Flights for Penetrating Trauma Justified?” The Journal of Trauma vol. 43 no. 1 (1997): 83-86.

Cook, C.H., P. Muscarella, A.C. Praba, W.S. Melvin, and L.C. Martin. “Reducing Overtriage without Compromising Outcomes in Trauma Patients.” Archives of Surgery (Chicago, Ill.: 1960) vol. 136 no. 7 (2001): 752-756, http://www.ncbi.nlm.nih.gov/pubmed/11448384.

Cudnik, M.T., C.D.Newgard, H. Wang, C. Bangs, and R. Herrington. “Distance Impacts Mortality in Trauma Patients with an Intubation Attempt.” Prehospital Emergency Care vol. 12 no. 4 (2008): 459-466.

Cunningham, P., R. Rutledge, C. Baker, and T. Clancy. “A Comparison of the Association of Helicopter and Ground Ambulance Transport with the Outcome of Injury in Trauma Patients Transported from the Scene.” The Journal of Trauma, Injury, Infection, and Critical Care vol. 43 no. 6 (1997): 940.

Davis, D.P., J. Peay, B. Good, M.J. Sise, F. Kennedy, A.B. Eastman, T. Velky, and D.B. Hoyt. “Air Medical Response to Traumatic Brain Injury: A Computer Learning Algorithm Analysis.” Journal of Trauma vol. 64 no. 4 (2008): 889-897.

Davis, D.P., J. Peay, J.A. Serrano, C. Buono, G.M. Vilke, M.J. Sise, F. Kennedy, A.B. Eastman, T. Velky, and D.B. Hoyt. “The Impact of Aeromedical Response to Patients with Moderate to Severe Traumatic Brain Injury.” Annals of Emergency Medicine vol. 46 no. 2 (2005): 115-122.

Davis, D.P., J. Stern, M. Ochs, M.J. Sise, and D.B. Hoyt. “A Follow-Up Analysis of Factors Associated with Head-Injury Mortality After Paramedic Rapid Sequence Intubation.” Journal of Trauma-Injury Infection & Critical Care vol. 59 no. 2 (2005): 484-488.

Eckstein, M., T. Jantos, N. Kelly, and A. Cardillo. “Helicopter Transport of Pediatric Trauma Patients in an Urban Emergency Medical Services System: A Critical Analysis.” Journal of Trauma vol. 53 no. 2 (2002): 340- 344.

Emerson, C. and D.L. Funk. “Automatic Helicopter Standby Policy for Seriously Injured Patients.” Air Medical Journal vol. 22 no. 4 (2003): 32-35.

Falcone, R.E., R. Johnson, and R. Janczak. “Is Air Medical Scene Response for Illness Appropriate?” Air Medical Journal vol. 12 no. 6 (1993): 191, 193-195; http://www.ncbi.nlm.nih.gov/pubmed/10128289.

Fromm, Jr, E. Hoskins, L. Cronin, C.M. Pratt, W.H. Spencer III, and R. Roberts. “Bleeding Complications Following Initiation of Thrombolytic Therapy for Acute Myocardial Infarction: A Comparison of Helicopter- Transported and Nontransported Patients.” Annals of Emergency Medicine vol. 20 no. 8 (1991): 892-895, http://www.sciencedirect.com/science/article/B6WB0-4FR609K- 1J6/2/0e35eca494a8869353393ec49cfca80.

Fromm, R.E., R. Haider, P. Schlieter, and L.A. Cronin. “Utilization of Specialized Services by Air Transported Cardiac Patients: An Indicator of Appropriate use.” Aviation, Space, and Environmental Medicine vol. 63 no. 1 (1992): 52-55, http://www.ncbi.nlm.nih.gov/pubmed/1550534.

Gabram, S.G., S. Stohler, R.K. Sargent, R.J. Schwartz, and L.M. Jacobs. “Interhospital Transport Audit Criteria for Helicopter Emergency Medical Services.” Connecticut Medicine vol. 55 no. 7 (1991): 387-392, http://www.ncbi.nih.gov/pubmed/1935060.

Hamman, B.L., J.I. Cue, F.B. Miller, D.A. O’Brien, T. House, H.C. Polk Jr, and J.D. Richardson. “Helicopter Transport of Trauma Victims: Does a Physician make a Difference?” The Journal of Trauma vol. 31 no. 4 (1991): 490-494.

Härtl, R., L.M. Gerber, L. Iacono, Q. Ni, K. Lyons, and J. Ghajar. “Direct Transport within an Organized State Trauma System Reduces Mortality in Patients with Severe Traumatic Brain Injury.” The Journal of Trauma vol. 60 no. 6 (2006): 1,250-1,256, http://www.ncbi.nlm.nih.gov/pubmed/16766968.

Housel, F.B., D. Pearson, K.J. Rhee, and J. Yamada. “Does the Substitution of a Resident for a Flight Nurse Alter Scene Time?” The Journal of Emergency Medicine vol. 13 no. 2 (1995): 151-153, http://www.ncbi.nlm.nih/gov/pubmed/7775784.

Jacobs, L.M., R.J. Schwartz, B.B. Jacobs, D. Gonsalves, and S.G. Gabram. “A Three-Year Report of the Medical Helicopter Transportation System of Connecticut.” Connecticut Medicine vol. 53 no. 12 (1989): 703-710.

Johnson, R. and R.E. Falcone. “Air Medical Response for Illness Revisited.” Air Medical Journal vol. 14 no. 1 (1995): 11-14, http://www.ncbi.nlm.nih.gov/pubmed/10140972.

Kerr, W.A., T.J. Kerns, and R.A. Bissell. “Differences in Mortality Rates among Trauma Patients Transported by Helicopter and Ambulance in Maryland.” Prehospital and Disaster Medicine vol. 14 no. 3 (1999): 159- 164.

King, D.R., M.P. Ogilvie, M.T. Pereira Bruno, Y. Chang, R.J. Manning, J.A. Conner, C.I. Schulman, M.G. McKenney, and K.G. Proctor. “Heart Rate Variability as a Triage Tool in Patients with Trauma during Prehospital Helicopter Transport.” Journal of Trauma vol. 67 no. 3 (2009): 436-440.

Klauber, M.R., L.F. Marshall, B.M. Toole, S.L. Knowlton, and S.A. Bowers. “Cause of Decline in Head-Injury Mortality Rate in San Diego County, California.” Journal of Neurosurgery vol. 62 no. 4 (1985): 528-531, http://www.ncbi.nlm.nih.gov/pubmed/3973722.

Koury, S.I., L. Moorer, C.K. Stone, J.S. Stapczynski, and S.H. Thomas. “Air Vs Ground Transport and Outcome in Trauma Patients Requiring Urgent Operative Interventions.” Prehospital Emergency Care vol. 2 no. 4 (1998): 289-292, http://www.ncbi.nlm.nih.gov/pubmed/9799016.

Lerner, E.B., A.J. Billittier, J.M. Dorn, and Y.W. Wu. “Is Total Out-of- Hospital Time a Significant Predictor of Trauma Patient Mortality?” Academic Emergency Medicine vol. 10 no. 9 (2003): 949-954.

Mango, N. and E. Garthe. “Statewide Tracking of Crash Victims’ Medical System Utilization and Outcomes.” Journal of Trauma–Injury, Infection and Critical Care vol. 62 no. 2 (2007): 436-460.

Mann, N.C., K.A. Pinkney, D.D. Price, and D. Rowland. “Injury Mortality Following the Loss of Air Medical Support for Rural Interhospital Transport.” Academic Emergency Medicine vol. 9 no. 7 (2002): 694, http://proquest.umi.com/pqdweb?did=140733811&Fmt=7&clientId=20485& RQT=309&VName=PQD.

McCowan, C.L., E.R. Swanson, F. Thomas, and D.L. Handrahan. “Outcomes of Pediatric Trauma Patients Transported from Rural and Urban Scenes.” Air Medical Journal vol. 27 no. 2 (2008): 78-83.

McCowan, C.L., E.R. Swanson, F. Thomas, and S. Hartsell. “Scene Transport of Pediatric Patients Injured at Winter Resorts.” Prehospital Emergency Care vol. 10 no. 1 (2006): 35, http://proquest.umi.com/pqdweb?did=1107232921&Fmt=7&clientId=20485 &RQT=309&VName=PQD.

McCowan, C.L., F. Thomas, E.R. Swanson, S. Hartsell, J. Cortez, S. Day, and D.L. Handrahan. “Transport of Winter Resort Injuries to Regional Trauma Centers.” Air Medical Journal vol. 25 no. 1 (2006): 26-34.

Moront, M.L., C.S. Gotschall, and M.R. Eichelberger. “Helicopter Transport of Injured Children: System Effectiveness and Triage Criteria.” Journal of Pediatric Surgery vol. 31 no. 8 (1996): 1,183-1,186.

Moylan, J.A., K.T. Fitzpatrick, A.J. Beyer, and G.S. Georgiade. “Factors Improving Survival in Multisystem Trauma Patients.” Annals of Surgery vol. 207 no. 6 (1988): 679-685.

Murphy, M.S., S.H. Thomas, P. Borczuk, and S.K. Wedel. “Reduced Emergency Department Stabilization Time before Cranial Computed Tomography in Patients Undergoing Air Medical Transport.” Air Medical Journal vol. 16 no. 3 (1997): 73-75, http://www.sciencedirect.com/science/article/B75B6-4CC83H0- N/2/440a7d7b5c72c40fb042d45a5d73e738.

Norton, R., E. Wortman, L. Eastes, M. Daya, J. Hedges, and J. Hoyt. “Appropriate Helicopter Transport of Urban Trauma Patients.” The Journal of Trauma vol. 41 no. 5 (1996): 886-891.

O’Malley, R.J., and M. Watson-Hopkins. “Monitoring the Appropriateness of Air Medical Transports.” Air Medical Journal vol. 13 no. 8(1994): 323- 325.

Owen, J.L., Phillips, R.T., Conaway, C., and Mullarkey, D. “One Year’s Trauma Mortality Experience at Brooke Army Medical Center: Is Aeromedical Transportation of Trauma Patients Necessary?” Military Medicine vol. 164 no. 5 (1999): 361-365.

Pettett, G., G.B. Merenstein, F.C. Battaglia, L.J. Butterfield, and R. Efird. “An Analysis of Air Transport Results in the Sick Newborn Infant: Part I. the Transport Team.” Pediatrics vol. 55 no. 6 (1975): 774-782, http://pediatrics.aappublications.org/cgi/content/abstract/55/6/774.

Poste, J.C., D.P. Davis, M. Ochs, G.M. Vilke, E.M. Castillo, J. Stern, and D.B. Hoyt. “Air Medical Transport of Severely Head-Injured Patients Undergoing Paramedic Rapid Sequence Intubation.” Air Medical Journal vol. 23 no. 4 (2004): 36-40, http://www.ncbi.nlm.nih.gov/pubmed/15224081.

Purtill, M., K. Benedict, T. Hernandez-Boussard, S.I. Brundage, K. Kritayakirana, J.P. Sherck, A. Garland, and D.A. Spain. “Validation of a Prehospital Trauma Triage Tool: A 10-Year Perspective.” Journal of Trauma vol. 65 no. 6 (2008): 1,253-1,257.

Rhee, K. J., M. Strozeski, R.E. Burney, J.R. Mackenzie, and K. LaGreca- Reibling. “Is the Flight Physician Needed for Helicopter Emergency Medical Services?” Annals of Emergency Medicine vol. 15 no. 2 (1986): 174-177.

Rodenberg, H. “The Revised Trauma Score: A Means to Evaluate Aeromedical Staffing Patterns.” Aviation, Space, and Environmental Medicine vol. 63 no. 4 (1992): 308-313, http://www.ncbi.nlm.nih.gov/pubmed/1610343.

Saffle, J.R., L. Edelman, and S.E. Morris. “Regional Air Transport of Burn Patients: A Case for Telemedicine?” Journal of Trauma vol. 57 no. 1 (2004): 57-64.

Safford, S.D., T.Z. Hayward, K.M. Safford, G.S. Georgiade, H.E. Rice, and M.A. Skinner. “A Cost and Outcomes Comparison of a Novel Integrated Pediatric Air and Ground Transportation System.” Journal of the American College of Surgeons vol. 195 no. 6 (2002): 790-795.

Savitsky, E. and H. Rodenberg. “Prediction of the Intensity of Patient Care in Prehospital Helicopter Transport: Use of the Revised Trauma Score.” Aviation, Space, and Environmental Medicine vol. 66 no. 1 (1995): 11-14, http://www.ncbi.nlm.nih.gov/pubmed/7695544.

Schiller, W.R., R. Knox, H. Zinnecker, M. Jeevanandam, M. Sayre, J. Burke, and D.H. Young. “Effect of Helicopter Transport of Trauma Victims on Survival in an Urban Trauma Center.” The Journal of Trauma vol. 28 no. 8 (1988): 1,127-1,134.

Schwartz, R.J., L.M. Jacobs, and R.J. Juda. “A Comparison of Ground Paramedics and Aeromedical Treatment of Severe Blunt Trauma Patients.” Connecticut Medicine vol. 54 no. 12 (1990): 660-662.

Snow, N., C. Hull, and J. Severns. “Physician Presence on a Helicopter Emergency Medical Service: Necessary Or Desirable?” Aviation, Space, and Environmental Medicine vol. 57 no. 12 (1986): 1,176-1,178, http://www.ncbi.nlm.nih.gov/pubmed/3800817.

Stohler, S.A., R.J. Schwartz, R. Kent Sargent, and L.M. Jacobs. “Quality Assurance in the Connecticut Helicopter Emergency Medical Service.” Journal of Air Medical Transport vol. 10 no. 8 (1991): 7-11.

Strong, C., R. Hunt, and J. Sousa. “Interhospital Transfer of Cardiac Patients: Does Air Transport make a Difference?” Air Medical Journal vol. 13 no. 5 (1994): 159.

Talving, P., P.G.R. Teixeira, G. Barmparas, J. Dubose, K. Inaba, L. Lam, and D. Demetriades. “Helicopter Evacuation of Trauma Victims in Los Angeles: Does it Improve Survival?” World Journal of Surgery vol. 33 no. 11 (2009): 2,469-2,476.

Thomas, S.H., T.H. Harrison, W.R. Buras, W. Ahmed, F. Cheema, and S.K. Wedel. “Helicopter Transport and Blunt Trauma Mortality: A Multicenter Trial.” Journal of Trauma vol. 52 no. 1 (2002): 136-145.

Thomas, S.H., C.K. Stone, and D. Bryan-Berge. “The Ability to Perform Closed Chest Compressions in Helicopters.” The American Journal of Emergency Medicine vol. 12 no. 3 (1994): 296-295.

Tiamfook-Morgan, T., C. Kociszewski, C. Browne, D. Barclay, S. Wedel, and S.H. Thomas. “Helicopter Scene Response: Regional Variation in Compliance with Air Medical Triage Guidelines.” Prehospital Emergency Care vol. 12 no. 4 (2008): 443, http://proquest.umi.com/pqdweb?did=1594822161&Fmt=7&clientId=20485 &RQT=309&VName=PQD.

Urdaneta, L.F., M.K. Sandberg, A.E. Cram, T. Vargish, P.R. Jochimsen, D.H. Scott, and T.J. Blommers. “Evaluation of an Emergency Air Transport Service as a Component of a Rural EMS System.” The American Surgeon vol. 50 no. 4 (1984): 183-188.

Urdaneta, L.F., B.K. Miller, B.J. Ringenberg, A.E. Cram, and D.H. Scott. “Role of an Emergency Helicopter Transport Service in Rural Trauma.” Archives of Surgery vol. 122 no. 9 (1987): 992-996.

Williams, K.A., R. Aghababian, and M. Shaughnessy. “Statewide Helicopter Utilization Review: The Massachusetts Experience.” The Journal of Air Medical Transport vol. 9 no. 9 (1990): 14-16, 18-21, 23, http://www.ncbi.nlm.nih/gov/pubmed/10106233.

Wirtz, M.H., C.G. Cayten, D.A. Kohrs, R. Atwater, and E.A. Larsen. “Paramedic Versus Nurse Crews in the Helicopter Transport of Trauma Patients.” Air Medical Journal vol. 21 no. 1 (2002): 17-21.

Wuerz, R., J. Taylor, and J.S. Smith. “Accuracy of Trauma Triage in Patients Transported by Helicopter.” Air Medical Journal vol. 15 no. 4 (1996): 168-170.