Chapter 7. Transportation of the Critically Ill Patient

• The objective of critical care transport is to provide an equivalent or higher degree of monitoring and medical care than the patient was receiving prior to transport.
• Each contemplated transport requires an evaluation of the risks and benefits of the transport.
• The risks to the patient during interhospital and intrahospital transport can be minimized through careful planning, use of appropriately qualified personnel, selection of appropriate transport equipment, and proper patient evaluation and stabilization.
• For interfacility transport, the referring physician is responsible for the transport-related decisions. It is common and appropriate for the receiving physician or critical care transport specialist to make recommendations regarding the mode of transport or need for specialty personnel or equipment.

In recent years, advances in bedside capabilities, diagnostics, and therapeutic interventions have dramatically improved care for critically ill and injured patients. In addition, comprehensive critical care units are no longer limited to academic and urban tertiary care centers, and have expanded to other clinical settings in suburban and rural areas. Despite these advances, the movement of critical patients may still be required for optimal patient care.

Transport of critically ill patients may be divided into two categories: transport within the hospital (intrahospital) and transport between hospitals (interhospital). Despite the evolution in the bedside management of critical patients, it is anticipated that the number of critical patients who will need to be moved from one location to another will not diminish. Patients in outlying hospitals will need to be transferred to critical care centers, and patients in critical care units may require transfer to intermediate or special care units. Also, with continued advances in medical technology, it is expected that more critically ill patients will require transport for sophisticated diagnostic studies and therapeutic interventions, such as magnetic resonance imaging (MRI), computed tomography (CT), nuclear medicine imaging, angiography, and gastrointestinal contrast studies.

From a historical perspective, the United States government began to pay a great deal of attention to highway-related accidents and fatalities with the passage of the 1966 National Highway Safety Act. By the early 1970s, civilian medical helicopters were being used in the prehospital transport of trauma victims and in the interhospital transport of critically ill and injured patients.

In contrast, despite these advances in prehospital and interhospital transport, very little attention had been paid to the transport of patients within a facility. Intrahospital transports of critically ill patients are more likely to occur and require the same comprehensive and systematic approach as the interfacility transports.

The focus of this chapter is on the transport of the critically ill or injured patient. These transports can originate from a number of locations that include the various intensive care units, the emergency department (ED), the operating room (OR), and so forth. Patients may go into the operating room with nothing more than a peripheral IV, but leave the OR intubated, with chest tubes, an arterial line, and various drainage tubes. More important than where the patient comes from is the patient's condition and the need for comprehensive monitoring and highly skilled medical personnel in attendance during the patient transport.

It has been well documented that critically ill or injured patients can be transported safely, without evidence of major complications and without adverse impact on clinical outcome.1–6 These studies support the transport of critical patients if the benefits outweigh the possible harm of the transport. The goal of critical care transport must be to minimize these risks and provide necessary ongoing care.

The movement of any critically ill or injured patient is not without hazard. Though these patients may be considered “stable,” their physiologic reserve is often limited. Even minor adverse physiologic changes in these patients during transport may cascade into life-threatening complications.

It is essential for everyone involved in the care of critical patients to have a basic understanding regarding the transport environment, personnel, equipment, and vehicles. Current technology makes it possible to nearly replicate the critical care environment during transport. Even with the best planning, personnel, and equipment, there may be times during transport when monitoring may be difficult and the capability to manage emergencies may be limited. As a result, ongoing therapy may be interrupted and a patient's clinical condition may be compromised.

While there are distinct differences between interhospital and intrahospital transport, there are numerous common concerns and considerations. To reduce transport-related risks, an appropriate level of monitoring and clinical support is necessary before departing the point of origin. It is not uncommon for these complex patients to have a variety of lines, tubes, and mechanical support devices that must be addressed before any patient movement is possible. Transport represents a period of potential cardiopulmonary instability for these critical patients. Central to a safe transport is the avoidance of any inadvertent interruption in the monitoring or maintenance of the patient's vital functions. Therapeutic modalities that are in place prior to transport must be continued to support the patient's airway, breathing, circulation, and disability, and to prevent physiologic complications.

Airway

Intubated patients are at risk for accidental extubation during transport. This is especially true during multiple transfers between beds, carts, and vehicles. Endotracheal tubes are to be secured and placement documented before the transport begins. It is also recommended that the placement be verified following the movement of the patient from bed to cart, cart to CT table, vehicle to vehicle, and so forth. Physical restraints or sedation may be applied as needed to prevent accidental extubation.

Securing and maintaining a patent airway is considered the highest priority of medical transport personnel. Making the head of the bed or stretcher easily accessible will facilitate airway control. Patients with an unstable or potentially unstable airway should be accompanied during transport by personnel who have the skill and necessary equipment to reintubate.7,8

Breathing

It is essential that adequate oxygenation and ventilation be maintained throughout the transport. Improper ventilation (overventilation or underventilation) may result in hypoxemia, hypocarbia, hypercarbia, or undesirable acid-base changes.

Some transport teams routinely use a portable transport ventilator, while others favor the bag-valve-mask (BVM) and manual ventilation. Weg and Haas9 concluded that manual ventilation during intrahospital transport is safe if the person doing the manual ventilation can approximate the pretransport inspired oxygen fraction and minute ventilation. In a prospective study by Braman and colleagues involving 36 critically ill, ventilator-dependent patients transported outside the ICU, a rise in PCO2 of at least 10 mm Hg during transport occurred in 14 of 20 patients manually bagged.10 Of the 16 patients transported using a portable mechanical ventilator, six patients showed significantly fewer changes in their arterial blood gases. Braman and colleagues concluded that the use of portable mechanical ventilators during transport might reduce the incidence of acid-base changes, cardiac arrhythmias, and hypotension. Nakamura and coworkers11 studied spontaneously breathing patients who needed ventilatory support during transport out of the ICU. They concluded that although both manual and mechanical ventilation could be used safely, the use of a transport ventilator with a patient-triggering function provided more consistent ventilation and less deterioration in the PaO2/FiO2 ratio.

Regardless of whether a portable transport ventilator or BVM ventilation is used, adequate oxygenation and ventilation must be assured. It is essential to establish an appropriate FiO2, tidal volume, rate of ventilation, and level of positive end-expiratory pressure (PEEP). While there are many transport ventilators that can perform comparably to traditional ICU ventilators, not all transport ventilators are created equal.12 Pressure limitations may make some transport ventilators incapable of providing high minute ventilation, airway pressures, or PEEP when these are required. In these types of patients, manual bagging for long periods of time may prove to be impractical.

There are many monitoring devices that may be helpful to the transport team, including a spirometric device (for bag ventilation), end-tidal CO2 monitors, transcutaneous PO2 monitoring, and pulse oximetry. Transport personnel should also assess for and document the symmetric rise and fall of the chest wall.

In recent years, the therapeutic options available to treat respiratory failure have advanced to include noninvasive mask ventilation (NIMV), inhaled nitric oxide (iNO), and heliox. Without portable delivery systems to continue treatment, patients may be severely compromised or transports may be impossible. Patients who require positive pressure ventilation via NIMV to treat their acute respiratory failure may quickly deteriorate if taken off the ventilator. Discontinuation of iNO, which may be used in the treatment of acute hypoxemic respiratory failure, may result in a rebound phenomenon, with worsened gas exchange and cardiovascular instability.13 The discontinuation of inhaled heliox may raise the work of breathing in obstructed patients, causing respiratory decompensation.14

Circulation

Cardiovascular and hemodynamic complications may be a direct result of patient transport. The severity of these changes during transport generally corresponds with the patient's status before movement out of the protective critical care environment. Complications commonly include hypotension, hypertension, and cardiac dysrhythmia. To reduce the risk of these preventable complications, vasoactive agents are continued, and electrolyte abnormalities should be corrected.

During the movement of patients, there is the possibility of dislodging intravascular lines or inadvertently disconnecting lines carrying drug infusions. Battery-powered infusion pumps can also fail. It is essential that there is careful attention and supervision to prevent these problems.

Disability

Neurologic compromise may be a direct result of the potentially life-threatening complications already identified, including hypoxia, hypotension, hypertension, hypoxemia, and hypercarbia. Cerebral ischemia and secondary brain injury yield a significant rise in mortality that may be preventable.

Andrews15 found that the most common complications during intrahospital transports that led to secondary brain injury included systemic hypotension and hypertension, increased intracranial pressure (ICP), decreased cerebral perfusion pressure, and arterial desaturation. It was determined that adequate resuscitation and stabilization before transport may have prevented some of these secondary injuries. Bekar16 observed that an increase in ICP might have been prevented by appropriate pretransport ventilation, sedation, and analgesia. If possible, patients with increased ICP should be transported with the head elevated. If a transducer and ventricular drain are in place, their heights are best kept at the pretransport level to prevent inaccurate readings or major cerebrospinal fluid shifts.

Minimum standards for intrahospital and interhospital transport of critically ill patients were developed by a committee from the Society of Critical Care Medicine, the American College of Critical Care Medicine, and the American Association of Critical Care Nurses.7 These guidelines list the minimum requirements for personnel, equipment, and medication to facilitate the movement of critical patients. Other associations and publications have also written standards and guidelines to ensure the appropriate and safe transfer of critically ill patients.17–20

While there are unique considerations for interhospital transport (e.g., vehicle selection), many issues regarding preplanning, equipment, and personnel are similar for both categories of transport (Table 7-1). Written hospital policies provide consistency and reduce the likelihood of intrahospital or interhospital transport errors.

Transport Personnel

The transport of critically ill or injured patients is not a benign endeavor. Critical care transports, both intrahospital and interhospital, should be performed by specially trained transport personnel.7 Whether it is a dedicated transport team, unit-based personnel, or on-call staff, it is essential for them to have the necessary training and experience for the unique transport environment. The medical personnel must also have the clinical abilities and equipment to adequately evaluate the critical patient and initiate appropriate treatment promptly.

Transport Equipment

For both interhospital and intrahospital transport, it is necessary that all equipment be appropriate for both the specific critical care patient and the transport environment. The basic equipment requirements are essentially the same whether you are transporting a patient several floors, several miles, or several hundred miles. Monitoring during the transport of critically ill patients should be similar to that received in the ICU. However, portable monitors have limited capabilities when compared with bedside monitors.21 In addition, monitoring during transport may be compromised by vibration, motion artifacts, electromagnetic interference, and limited visibility.

Critically ill or injured patients require real-time monitoring. Pulse oximetry and electrocardiographic (ECG) monitoring can provide continuous oxygenation and cardiac assessment. The blood pressure can be measured using an automatic noninvasive blood pressure device if continuous measurements via arterial line are not indicated.

Suitable transport monitors and equipment are portable, durable, lightweight, and battery powered. The capability to be plugged directly into a power source helps prevent unnecessary battery consumption. Audible and visible alarms for monitors, infusion pumps, and ventilators are necessary in quickly assessing important patient changes or equipment failures. It is also important to be certain that transport equipment will be compatible with the lines, fittings, and power outlets at the destination unit or in the transport vehicle.

All transport equipment should fit into elevators and transport vehicles, while leaving enough room for transport personnel to function. The ability to secure the equipment within the transport vehicle or to the patient's bed improves visibility while protecting it from accidental damage. Some ICU, ED, and OR beds have footboards that can double as equipment trays. Some institutions have designed trays or carts that can attach directly to the patient bed.

Limiting the number of bed-to-bed transfers will further reduce the likelihood of an inadvertent equipment disconnect. Several military and commercially available self-contained stretcher-based miniature ICUs or modified beds have been designed for adults, children, and neonates. They are equipped with ventilators, cardiac monitors, blood pressure monitors, and infusion pumps, and some are compatible with radiologic equipment. These devices may result in a more efficient use of resources necessary to safely transport a critically ill patient and reduce movement from cart to cart.

Besides the equipment used for monitoring and physiologic support, airway (intubation) and IV equipment and medications must also be available and transportable. Transport medications include the standard resuscitation drugs, analgesics, sedative/hypnotic agents, and neuromuscular blocking agents as indicated. Commercially available carrying cases that contain these essentials help to efficiently organize these supplies.22 Numerous organizations and publications provide lists of suggested equipment and medication for in-house transport or interfacility transport.

A failure in oxygen supply can have disastrous consequences when caring for the critically ill. Therefore it is important for the oxygen source to be sufficient to exceed, by a substantially safe margin, any patient transport time.

Transport equipment often differs from routine bedside equipment. Dedicated transport personnel, working in a familiar environment, may better test, maintain, and troubleshoot complex equipment than those who only occasionally are called to accompany a patient during transport. All personnel must assure properly functioning equipment before departure.

Most commonly, interhospital transfers occur when a referring facility lacks sufficient resources, equipment, personnel, or expertise to meet the needs of the critically ill or injured patient. The patient may require further diagnosis, specialized care, or timely treatment that is not available at the referring hospital. There are data supporting the value of regional referral centers, as well as the organized systems and specialized teams to bring patients safely to them.23,24 Nevertheless, there remain common misconceptions among many physicians that some patients are too ill to transfer. This generally stems from a lack of knowledge regarding sophisticated patient transport systems.25

In the past decade, changes in how decisions regarding patient transfers are made have occurred due to changes in government regulations, methods of reimbursement to hospitals, and third-party managed care providers.26,27 It is not uncommon for patients (or their designees), their personal physicians, or managed care providers to request transfers to a specific hospital that may have similar critical care capabilities to those at the referring facility. These lateral transfers may be motivated by many factors, including continuity of care, patient (or family) preference, or insurance plan requirements, and their appropriateness is often controversial.

There are three essential participants in a successful interfacility transport that can be viewed as a “transfer triangle.” This 3-cornered approach has the referring and receiving physicians/facilities at the bottom corners of the triangle, creating the foundation for the patient transfer. Direct physician-to-physician contact and exchange of patient information is optimal, but in many situations physicians may rely on a designee to coordinate a transfer between facilities. At the apex of the triangle are the transport personnel, in contact with both the referring and receiving facility, and serving as a vital link between them. Working together, these collaborators should assure that each patient transfer results in the appropriate utilization of available resources, which include vehicles, personnel, and equipment.

Responsibilities of the Referring Physician and Facility

If a treating physician recognizes that hospital capabilities are inadequate to safely care for a critical patient, or if specialized treatment or expertise is indicated but not available, the patient will need to be transferred to a facility capable of providing these services. Knowing the services a referring hospital provides is best addressed prospectively in hospital policy so that all hospital physicians, administrators, and staff have the same information readily available.

In addition to the above medical responsibilities during interfacility patient transfers within the United States, referring facilities and physicians face several legal obligations. The interhospital transport of critical patients may be initiated from referring emergency departments, inpatient units, and other various locations. When the transfer is from an emergency department within the United States, the Emergency Medical Treatment and Active Labor Act (EMTALA)28 requires that all unstable patients be transported by qualified personnel and transportation equipment. Transport decisions are no longer merely a patient care issue, but also a federal requirement for EMTALA compliance.

EMTALA was established in 1986 and created patient stabilization and transfer requirements for hospitals and physicians. The law applies to any individual who “comes to the emergency department," but interpretation by the Centers for Medicare & Medicaid Services (CMS) has clearly expanded this to include other areas of the hospital campus. The original EMTALA regulations did not specifically address the interfacility transfer of unstable admitted patients. As a result, varying conclusions had been reached in different federal courts and regional CMS offices. However, in September 2003, CMS published new regulations to resolve this issue. CMS concluded that “the transfer and stability issues for a patient, once he or she is admitted, are governed by the Medicare hospital conditions of participation, State law, and professional considerations, not EMTALA requirements.”29 While CMS has clarified its position regarding the admitted patient, the basic EMTALA transfer provisions seem to be in the best interest of the patient and therefore warrant careful consideration.

If an individual presents to the ED with an “emergency medical condition," a hospital cannot transfer the patient unless specific requirements are met. The referring hospital is to examine the patient and “provide the medical treatment within its capacity which minimizes the risks to the individual's health.” If the hospital cannot stabilize a patient, then the patient may be transferred (an “appropriate transfer” under EMTALA) only after complying with the remaining provisions of the law. EMTALA does not allow for an “automatic transfer” from one hospital to another based on established referral patterns or affiliations (e.g., managed care, trauma systems, and perinatal networks, among others).

The referring physician determines which receiving facility and physician is most appropriate for the patient. The most appropriate hospital may not always be the closest. A more distant facility may be preferable, but not practical due to a lack of time or means of transport. In addition, a specific institution may be deemed more appropriate if they have a specialized transport team that can provide an appropriate level of care during the transport.

Ideally, in consultation with the receiving physician, the referring physician verifies that the receiving facility has the available space, can provide the appropriate medical treatment, and agrees to accept the transfer. Finally, it is also the referring physician's responsibility under EMTALA to be certain that “the transfer is effected through qualified personnel and transportation equipment, as required including the use of necessary and medically appropriate life support measures during the transfer.”

It is necessary for the referring physician to explain to the patient (or family) the reasons for transfer, the receiving facility and physician, and the method of transport. Considerable time may be lost if a transfer is set into motion only to have family members refuse the selected receiving hospital or mode of transport. Written, signed consent for transfer is to be obtained by the referring hospital. Many transport teams use their own supplemental consent forms as well.

A summary of the risks and benefits of a transfer are to be included in the patient records. It is no longer adequate to simply state that the benefits of transfer outweigh the risks. EMTALA requires that specific risks and benefits be considered and explained to the patient or the “legally responsible person acting on the individual's behalf.” Some hospitals have prepared forms with checklists to facilitate completion of the necessary transfer documents. All medical records (or copies) related to the emergency condition, preliminary diagnosis, treatment provided, results of any tests, and the informed written consent for transfer are to be sent by the referring hospital to the receiving facility.

For patients transferred from the inpatient setting, the medical records should include copies of the physicians' and nurses' notes, consultations, medication sheets, order sheets, flow sheets, ECGs, radiology reports, lab results, and pertinent x-rays. Whenever possible, a discharge summary or transfer note is included. This document summarizes the major events in the patient's hospital course, and should be readily available for the transport team to review. With appropriate planning, the medical records and x-rays are copied and available at the patient's bedside before the transport team departs.

Responsibilities of the Receiving Physician and Facility

Any hospital that strives to be a regional resource and receiving hospital for critical care referrals should have a system in place to facilitate communications and transfers. Communications can be enhanced through a designated communications or transfer center, dedicated telephone lines, or the hospital operator. The most efficient tertiary care centers have a consulting/receiving physician available 24 hours a day who has the authority to accept transfers and experience in off-site patient management.

Being familiar with hospital resources, bed availability, and transport options will expedite transfer decisions. Once the patient is accepted for transfer, the referring and receiving physicians should agree on the mode of transport, the transport team composition, and the equipment that may be necessary during the transport.

Federal law also has implications for receiving institutions. EMTALA identifies “obligations of hospitals with specialized services,” and specifies that “participating hospitals with specialized facilities shall not refuse to accept an appropriate transfer if they have the capacity to treat the individual.” Receiving hospitals should document in hospital policy which of their services are “specialized,” addressing the capabilities and capacities of these services. Under EMTALA, a receiving hospital cannot refuse to accept the transfer of a patient who is unstable or has an emergency medical condition if they have the capacity and ability to care for a patient.

Coordination of the Interhospital Transfer

It is the referring physician who is ultimately held accountable to coordinate the transfer of a critical patient. Formal transfer policies and transport agreements between the referring and receiving hospitals and physicians can greatly facilitate patient transfers while minimizing EMTALA violations and preventable delays. Regional tertiary and specialty care centers (ICUs, trauma centers, burn units, and transport services) are best listed in these resource documents.

Patient transfer agreements identify the available specialty areas at potential receiving hospitals and the admission criteria for each of these services. Including the point(s) of contact, key telephone numbers, and procedures to secure patient acceptance are also helpful. Transfer agreements with multiple facilities for the various specialty services may be needed, as an individual hospital may at times be unable to accommodate a patient.

Patient transport procedures and agreements may also be incorporated into patient transfer agreements, or may be separate contracts with independent third-party transport services. Third-party transport providers may be independent or hospital transport services. Many transport agreements delineate the availability and composition of transport teams, medical crew capabilities, and resource availability (medical equipment and transport vehicles). When appropriate, this document may also address issues of billing and payment, and clarify questions pertaining to medical control during transport. Transport agreements streamline patient transfer by minimizing delays in processing a transport request. A resource directory that includes phone numbers, specific capabilities of each air or ground transport service, and receiving medical facilities should be readily available in the ICUs and ED.

A timely and accurate initial contact with a receiving physician will minimize delays, facilitate decision making, and promote transfer arrangements. Ideally, to assure a smooth and safe transfer, the referring and receiving physician discuss the patient directly. Without this interaction, significant gaps in the transfer of essential patient information may occur, resulting in missed or delayed diagnoses and treatment. It is often helpful for the referring and receiving physicians to use a systematic checklist to review and fill out while discussing the patient.

To begin the process, the referring physician provides his or her name and easy access callback number, which may be a specific telephone number, pager number, or mobile phone. The name and phone numbers of the referring hospital and unit should be logged by the receiving institution to facilitate follow-up phone calls. The patient's name, age, nature of illness or injury, vital signs, physical findings, results of pertinent diagnostic studies, treatment, current condition, and reason for transfer are described in detail to the receiving physician. This same information will need to be relayed to the transport team by physicians and eventually to the nursing staff at the receiving facility.

Once the patient is accepted for transfer, it is appropriate for the accepting physician to make recommendations regarding ongoing patient management. Both the referring and receiving physicians should document these recommendations.

In addition, the receiving physician or a specialist who is frequently involved in the transport of critically ill or injured patients may make recommendations regarding the mode of transportation, composition of the transport team, and preparation of the patient prior to transport. This happens most often when the receiving facility has its own critical care transport team. However, a receiving hospital cannot insist that their own transport team undertake a transport in order for them to accept the patient in transfer.

Critical transport decisions are often made under adverse conditions with limited information and limited time. The emphasis is on protecting the patient from further injury or medical deterioration, and optimizing the patient's chances for survival. Individuals with the most experience in transport should be a part of the transport decision making process. However, despite external recommendations of others, it remains the responsibility of the physician caring for the patient at the referring institution to make the transport-related decisions.

Transport Decision Making

Anticipating patient care requirements prior to and during transport determines the method of transport. EMTALA states that the transfer is “effected through qualified personnel and transportation equipment.” However, the law does not define “qualified.” This leaves the interpretation and responsibility primarily up to the referring physician. In practical terms, the skills of the transport personnel include the ability to care for the patient's current condition and any reasonable foreseeable complications that could arise during transport. It is not possible to predict all the potential complications that may occur during any given transfer. However, it is imperative for referring facilities and physicians to have a reasonable understanding of the capabilities of transport services within their service area, even if that service is provided by the receiving hospital or a third party.

There are several key decisions to consider when making arrangements for a patient transport, including the personnel, the type of vehicle, and the proper equipment or medications to have on hand. The referring physician must accurately assess the patient's real and potential illnesses or injuries and anticipate complications that might occur during transport. He must also estimate the pace of illness in order to judge whether “team or time” represents the greater opportunity to improve outcome.

Level-of-care options for interfacility transport include basic life support (staffed by EMTs), advanced life support (staffed by two paramedics), and critical care/specialty care (staffed by a minimum of a nurse and a second crew member). The special requirements of high-risk neonates, complex obstetric patients, and those needing complex ventilator or hemodynamic management may dictate the transport personnel and equipment. However, for time-dependent disorders, urgent transfer may be more crucial than specialty transfer. For example, because a patient with a dissecting aortic aneurysm may require immediate surgical intervention, delaying the transport for a critical care transport team may be inadvisable. A dilemma arises when the patient's medical condition is both time-dependent and team configuration–dependent. Specialists experienced in transport medicine can greatly assist in making these complex judgments.

Vehicle Selection

In determining the most appropriate method of transport, several considerations are addressed, including the availability of local resources (referring hospital, receiving hospital, and ambulance services, among others); speed of the transport vehicle; weather considerations (inclement weather, snow, or fog); ground traffic, construction, or accessibility of roads and landing areas (helipads or airports); and the total distance to travel to deliver the patient (one-way vs. round trip or two legs of a three-legged transport). A vehicle dispatched directly from the referring hospital to the receiving hospital constitutes a one-way transport. More commonly, the transfer will be two-way, with the vehicle and crew being sent from the receiving hospital to the referring hospital to pick up the patient. Three-legged transports describe those in which a third party (hospital-sponsored program or independent ambulance company) provides the vehicle and team from a location other than the receiving or referring hospital. Options for transport include ground and air ambulances (helicopter and airplane).

Ground Ambulances

Ground ambulances are the most common vehicles used for interfacility transport and continue to be the primary means of prehospital patient transport. A major advantage is availability, since most geographic areas have ground ambulances. They also provide door-to-door service, without the need for a runway, helipad, or landing zone. Once placed on the stretcher and secured in the ambulance, the patient can be transported directly to the receiving facility without movement from one vehicle to another, limiting the most dangerous aspect of transport. The patient compartment of a ground ambulance tends to be larger than those found in helicopters and airplanes, accommodating up to four medical crew members and one to two patients. In addition, fewer restrictions apply to the size, weight, and amount of equipment that can be taken by ground transport when compared to flying. It is also easier to stop a ground ambulance to facilitate patient assessment and intervention. If necessary, ground ambulances can also be easily diverted to alternate destinations as dictated by patient condition or the need for an unanticipated intervention. Finally, ground ambulances operate in most weather conditions that restrict safe air operations.

There are also disadvantages to using ground ambulances, the most important being the increased amount of time required to transfer a patient from one facility to a distant facility in comparison to air transport. Ground vehicles are subject to delays imposed by poorly maintained roads, traffic congestion, construction, and inclement weather. In addition, ground ambulances may not be able to gain access to patients who are located in remote areas with limited road availability. In rural areas with limited numbers of ground ambulances, the dispatch of one unit on a distant transport may cause other areas to be temporarily without service. Finally, tight vehicle suspensions, narrow wheelbases, and high centers of gravity predispose ground vehicles to rough and turbulent rides, which may be detrimental or excessively painful to patients with spinal cord injury, intracerebral hemorrhage, or orthopedic injuries.

Rotor-Wing Air Ambulance (Helicopter)

The use of the air ambulance has grown significantly over the past 30 years. Speed of travel is an important consideration for helicopter transport and the primary reason it is chosen over ground ambulances. Depending on the type of aircraft, weather conditions, flight altitude, and total load, helicopters may travel at speeds of 120 to 180 miles per hour. This speed and the fact that helicopters can make direct point-to-point transfers may reduce transport time to one third to one fourth that required by ground transport. The helicopter needs only a small (100-by-100-foot), flat area that is clear of obstructions to take off and land. In addition, the helicopter has the ability to fly into locations inaccessible to other modes of travel. This capability becomes extremely valuable when traffic is delayed or roads are impassable after snowstorms, floods, tornadoes, and other disasters, or when a patient is located in rural or wilderness areas. With a service area that generally ranges between 50 to 200 radial miles from its base, helicopters cover a much greater service area than would a ground ambulance, but less than a fixed-wing aircraft. Helicopters are often the fastest mode of transport for distances of 25 to 150 miles.

Helicopters also have inherent disadvantages. If an appropriate landing area is not readily available, the time needed to identify and secure a landing zone, in addition to the time needed to transport the patient to and from the distant landing site, may erode the helicopter's speed advantage. The patient cabin is typically smaller than in ground ambulances, and even in larger helicopters, patient access may be limited. Weight restrictions may also prevent transport of some obese patients.

Fog, sleet, heavy snowfall and rain, low clouds, high winds, and lightning may significantly limit the utility of helicopter transport. Most helicopter programs operate under visual flight rules (VFRs), but travel under instrument flight rules (IFRs) is becoming more common. The majority of IFR flights are conducted airport-to-airport, but newer Global Positioning System (GPS) technology makes possible IFR missions directly to precertified hospital helipads.

Helicopters are unpressurized and a basic knowledge of flight physiology is important to understanding the effects of a changing altitude are essential. While airplane travel is clearly impacted by flight physiology and the stresses of flight, helicopter transport is also susceptible. It is often thought that only altitudes above 8000 feet impact the patient or crew, but this is not always the case. Boyle's law states that, as altitude increases and atmospheric pressure decreases, gas volumes expand (and vice versa on descent). As a result, crew members or patients flying with sinus problems, ear problems, or upper respiratory infections may feel the effects of barometric pressure changes with an altitude change of as little as 1000 to 2000 feet.

Henry's Law is another important gas law affecting air medical transport. According to this law, the amount of gas dissolved in liquid is determined by the partial pressure and the solubility of the gas. The bends, a decompression sickness, is a clinical condition affected by this law. When a scuba diver ascends too quickly, nitrogen gas bubble formation in the blood can occur. Special precautions should be taken for decompression victims who must be transported by helicopter. In some cases, even a minimal gain in altitude can cause significant gas bubble formation. It is advised that patients suffering from decompression illness be transported in non-pressurized aircraft at an altitude of not more that 1000 feet about the diver's ascent.

Patients, medical personnel, and pilots may all be impacted by the stresses of flight. Vibration, noise, and turbulence are generally more severe in helicopters than in other forms of transportation, and they may interfere with patient assessment or the function of medical equipment. Flight crew members wear headsets or helmets to facilitate in-flight communication and to minimize the long-term effects of working in a loud environment. Awake patients are commonly given headsets or earplugs.

Fixed-Wing Air Ambulance (Airplane)

Fixed-wing transports usually lose their speed advantage at distances of less than 100 miles because of ground delays during airport transfers. Furthermore, these additional patient transfers to and from ground ambulances expose the patient to possible dislodgment of vital equipment. Despite these disadvantages, fixed-wing aircraft offer several advantages. Airplanes often have sufficient space to accommodate more than one patient, patient family members, and additional crew members or equipment. In addition, weight restrictions, weather, noise, and turbulence are less of a factor when compared to rotary-wing transport. Smaller unpressurized airplaines offer no benefit over the helicopter in combating the effects of the gas laws, and therefore are generally limited to altitudes under 10,000 feet. Pressurized fixed-wing aircraft, however, can fly higher while counteracting the negative effects of altitude. At flight altitudes of 30,000 to 40,000 feet, pressurized aircraft can often create an internal cabin altitude of 7000 to 8000 feet. Flying at lower altitudes, aircraft with a high differential cabin pressure have the ability to create a cabin pressure that exceeds ground altitude pressures, a feature that may aid in transport of victims with decompression illness.

Due to the impact of Boyle's Law, on ascent a simple pneumothorax may expand to become hemodynamically significant or intestinal gas may expand to rupture a hollow viscus. Medical equipment that has an enclosed air space can also be affected, including endotracheal tube cuffs, intravenous lines (whose flow may be driven by air-filled pressure bags), and air-containing splints.

Hypoxia represents the greatest risk associated with high-altitude transport. Dalton's law states that the total pressure of a gaseous mixture is equal to the sum of the partial pressure of the gases. Therefore, any change in barometric pressure directly affects the partial pressure of oxygen (Table 7-2).

During fixed-wing transport, the most threatening concern with hypoxia is its insidious onset. The medical crew may not notice the early onset of signs or symptoms in the patient or themselves.30 No one is exempt from the effects of hypoxia, even though the onset and severity of symptoms may vary with individuals. While altitude-related patient hypoxia is a concern, the routine use of pulse oximetry and supplemental oxygen minimizes this hazard. In the setting of hypoxemia, increasing FiO2levels or adding PEEP easily compensates for the hypoxic effects of altitude. However, in the rare patient who is on maximal oxygen support, flight at lower altitudes may allow the artificial cabin pressure to approach sea level, in this manner increasing the partial pressure of oxygen.

Hypoxia is more of a concern for the pilots and crew members who generally are not monitored. The Federal Aviation Administration (Federal Aviation Regulations [FAR], Part 135, which applies to on-demand air taxis) requires pilots to use supplemental oxygen if they are flying at cabin altitudes above 10,000 feet for more than 30 minutes and any time above 12,000 feet.31 At cabin pressure altitudes above 15,000 feet each occupant of the aircraft must use supplemental oxygen.32 During high-altitude transport, periodic assessment of the pulse oximetric saturation of medical crew members is prudent.

The medical crew must be prepared to deal with the effects of a malfunction of the pressurization equipment or aircraft structural damage. During a rapid decompression, the sudden drop in temperature causes the aircraft to fill with fog. A rapid drop in the cabin PO2 quickly leads to hypoxia in crew members. Supplemental oxygen for the pilot, medical crew, and patient is essential. Any chest or nasogastric tube should then be unclamped to allow decompression of any gas subject to expansion.

Efficacy of Air Medical Transport

Despite over 30 years of air medical transport, definitive data indicating which types of patients should be flown are generally lacking. Questions regarding the triage of patients to air or ground transport, the efficacy of aeromedical care, and the effects of air medical transport on morbidity and mortality in both medical and surgical conditions remain controversial. To assist programs and physicians in determining the appropriateness of air medical transport, the Medical Advisory Committee of the Association of Air Medical Services has established criteria for the proper utilization of air medical transport.33 These time, distance, and logistical indicators have been adopted by many air medical programs and EMS systems to aid in the appropriate triage of patients. An example of these general criteria for the adult nontrauma patient is summarized in the form reproduced as Figure 7-1.

Trauma patients have been the most studied with regard to helicopter EMS transport. Studies have shown that patients transported by aeromedical services may exhibit improved survival.34–36 When patients are transported from rural areas, the higher level of care aboard the medical helicopter and the timely arrival to a trauma center were felt to be the main contributing factors to decreased mortality. The helicopter appears to provide no advantage for patients transported from an urban area.37,38

Transport of cardiac patients has raised concern because altitude raises heart rate and myocardial oxygen demand. Studies of patients with acute myocardial infarction and unstable angina revealed that complications such as hypotension, dysrhythmias, and exacerbation of chest pain occurred during transport and that most were managed effectively en route.39,40 In one study, complications were more frequent in the group transported by air when compared to those transported by ground.41 In general, it was found that major in-flight events were uncommon.40–42

Aeromedical transport of the gravida is felt to be generally safe for both mother and fetus. If the fetus is at risk, the mother should be given supplemental oxygen during flight.43Another concern is the transport of women in active labor, since in-flight delivery is best avoided. It may be wise to defer transport of the patient whose cervix is dilated greater than 4 cm on preflight assessment.44

Safety of Transport

Accidents occur with all modes of patient transport. Generally speaking, ground ambulances have a higher probability of being involved in an accident, but offer a better chance of survival than aircraft mishaps. A safety report published by the Air Medical Physician Association researched accident data for ground and helicopter EMS (HEMS).45

Since 1972, HEMS has flown an estimated 3 million hours while transporting approximately 2.75 million patients. In 31 years (through September 2002) there were 162 HEMS accidents in the United States, 67 of them fatal, with 183 deaths including 21 patients. From 1987 to 1997, HEMS averaged 4.9 accidents per year, but this has risen since 1998 to 10.75 accidents per year. Over the course of the 22 years reviewed, the death rate for HEMS patients was 0.76 per 100,000.

EMS experts estimate that 15,000 ground ambulance crashes occur each year, with as many as 10,000 injuries annually, 10 serious injuries daily, and 1 fatal ambulance crash each week. “Emergency vehicle passengers,” which includes patients, medical personnel, and patient's family members account for 22% of the fatalities, with most deaths being occupants of the other vehicles.

Medical Personnel for Interhospital Transport

Air and ground transport present many unique challenges to its medical personnel. Numerous associations and many state EMS agencies have developed training requirements for critical care transport. In addition to the appropriate clinical components, knowledge of altitude physiology and the stresses of transport, vehicle safety, stress management, and appropriate survival training are included.

Factors other than direct patient needs may determine the composition of the transport team. Since critical care transport teams are expensive, financial considerations may affect crew composition and availability. Utilizing in-house or on-call staff to transport patients may reduce the cost of transport, but this may result in crew members being unfamiliar with the transport environment and could deprive the home institution of adequate physician or nurse coverage. Receiving or referring physicians may also request the presence of a transport physician to ameliorate a perceived decrease in the level of care provided during a transport.

Medical personnel for interfacility transport represent the broad spectrum of health care providers. EMS ground ambulances are commonly staffed with paramedics who function at advanced life support (ALS) level, or emergency medical technicians (EMTs) who provide basic life support (BLS). Referring physicians must carefully evaluate the needs of critical care patients and the capabilities of ground EMS providers to determine if optimal patient care can be accomplished by these caregivers.

The majority of fixed-wing (61%) and rotor-wing (71%) programs in the United States staff their critical care transport teams with a nurse/paramedic crew. Nurse/nurse is the next most common medical crew configuration for both helicopter and airplane transport (8%). Other team combinations of registered nurses, EMTs, doctors, and EMT-paramedics (RN/EMT, RN/MD, and EMT-P/EMT-P) each account for 5% or less of the totals.46

Flight nurses generally have extensive experience in intensive care units or EDs. Paramedics often make their greatest contribution in the transport of critical patients from accident scenes since most of their training revolves around being first responders. Respiratory therapists bring expertise in airway and ventilator management and oxygen delivery systems.

The benefit of physicians on medical transport teams, as is common in Europe, remains unclear. Studies are conflicting on the subject of whether physician attendance improves patient outcome.47–50 Optimal transport systems have the flexibility to send a physician on a case-by-case basis. Flight physicians are often residents in emergency medicine or surgery, and on occasion they may be attending physicians or medical directors of flight programs.

In some regions, transport services provide specialty care teams for specific patient populations, most commonly for pediatric critical care patients, high-risk neonates, or high-risk obstetric patients. Some nonspecialty teams may replace a team member or provide additional personnel for certain missions, such as intra-aortic balloon pump transports. A limited number of studies compare specialty teams to nonspecialty teams. Edge and colleagues found that adverse events occurred in only 1 of 49 (2%) pediatric transports by a specialized team compared to 18 of 92 (20%) of transports by nonspecialized personnel.51 In another study comparing 1030 transports by a pediatric specialty care team to 55 transports by a nonspecialty care team, children were 22 times more likely to have an unplanned event and 2.4 times more likely to die when transported by a nonspecialty care team.52 The most common unplanned events identified were airway problems (specialty, 0.4%, nonspecialty, 18%) and hypotension (specialty, 0.1%, nonspecialty, 10.9%).

The Transport

Once the transport team arrives at the referring location, it is essential that a thorough but expeditious patient assessment be completed. Considerations include taking the time to perform stabilizing interventions prior to departing the referring unit. Gebremichael and colleagues6 concluded that patients with profound respiratory failure benefited when stabilized prior to transport. However, with trauma patients53,54 and cardiac patients,55 it has been shown that rapid transport with minimal stabilization prior to transport may be beneficial, since the delay in getting to definitive care or therapeutic intervention is minimized.

Decisions regarding airway management are critical when it comes to interfacility transport. While patients can be intubated in the various transport vehicles—sometimes with extreme difficulty—it may be preferable to intubate in the more controlled environment of the referring unit. The threshold to intubate for transport may be appropriately lower compared to a patient who would otherwise not be leaving the in-hospital setting.

In preparing a patient for transport, other anticipated therapeutic changes are also best handled initially in the referring unit in order to determine the patient's response. Changing to a portable ventilator or to manual ventilation within the controlled ICU, ED, or OR setting will enable the transport team to identify any ventilation or oxygenation complications that arise and correct them before leaving the unit. A change in any medication to support the patient's blood pressure or cardiac rhythm is also best handled initially in the referring unit. It is often preferable to simplify transport by limiting the number of continuous IV infusions to necessary vasoactive agents and volume expanders. Paralytics and sedatives may be given by IV bolus during transport rather than by continuous infusion.

Medical Direction and Medical Control

All medical transports require some form of medical direction and medical control. ALS ground ambulances are generally under the direction and control of an EMS system. Individual transports would generally be under the direction of an EMS resource hospital or standing medical orders (SMOs). Hospital-sponsored or independently operated air medical services or mobile intensive care programs generally have their own medical direction and medical control physicians.

While EMTALA leaves the transferring physician responsible for patients in transfer until they physically arrive at the receiving facility,56,57 the law does not make any reference to the transport service, its medical director, or medical control. Out-of-hospital medical transport is regulated state by state, with all states requiring some type of physician medical direction and medical control.58

There are three options for medical control. On-line medical control represents direct real-time voice communication between the medical control physician and the transport team. With off-line medical control there is no direct contact between the transport team and the medical control physician. Written medical protocols or standing orders provided by the medical director, medical control physician, referring physician, or receiving physician will direct patient management. Visual medical control occurs when a physician is physically present during the transport.

Medical control during interfacility transport may be assumed by the transferring physician, receiving physician, EMS base station, or the medical director/designee of the transport service. The National Association of EMS Physicians (NAEMSP) has concluded that medical direction of the interfacility transport is a shared responsibility,58 stating that the referring physician, transport service medical director, and accepting physician should agree on the responsibility of medical direction prior to the transport. The Air Medical Physician Association (AMPA), however, believes that medical control during transport should remain the responsibility of the air medical director or his or her designee.59 AMPA states that any variation from this standard should be specified in a patient transfer agreement or at the time of request for air medical transport.

It is important to note that despite having interfacility transfer and transport agreements in place, the requirements of EMTALA are still in effect. Some physicians believe that the presence of a physician on the transport team relieves the referring physician of his or her liability and obligations. Others feel that when a transport team from the receiving hospital arrives at the referring facility and assumes patient care, the patient is considered to be admitted to the receiving hospital and that the responsibility shifts completely to the receiving institution. While these shifts of authority and liability may be implied or incorporated into transfer agreements or hospital policies, nothing in EMTALA can be interpreted to endorse these beliefs. The transferring physician and hospital may only decrease their liability and accountability by prospectively addressing these issues in transport agreements and hospital policies, but the responsibility for an “appropriate transfer" remains with the referring hospital and physician. Ideally the transferring physician is available and continues to assist in patient care until the patient has physically left the facility. The medical control physician, however, is responsible for the care provided by transport personnel during patient stabilization and preparation for transport. If a difference of opinion occurs regarding options for care, the referring physician and the medical control physician must reach an accord. This is when knowledge and experience regarding the transport environment is most important to ensure the quality of medical care and the safety of transport.

For the critically ill patient, it may be preferable for diagnostic studies and therapeutic or surgical procedures to be done at the bedside in the ICU or ED. This avoids the inherent hazards of transport outside of the unit and provides the patient with the additional benefits of the ICU environment, including advanced monitoring capabilities, and presence of additional critical care personnel who may provide additional assistance as needed. However, critical patients may require procedures that cannot be performed in the ICU or ED itself. Patients may need to be transported to the radiology department, operating room, or other locations within the hospital to receive specialized diagnostic or therapeutic procedures. In addition, many patients now leave the ICU for intermediate care units while still marginally stable and often with multiple indwelling catheters and other devices.

Intrahospital transport of critical patients has been associated with significant clinical complications. Braman and colleagues10 found that 75% (15 of 20) of ventilator-dependent ICU patients had an increase in PCO2,with corresponding hypotension or cardiac dysrhythmias. These patients were transported using manual ventilation. Indeck and associates60 reported a total of 113 serious physiologic changes of at least 5-minute duration during intrahospital transport. Of the 103 patients in the study, 68% experienced complications, including a change in systolic or diastolic blood pressure of at least 20 mm Hg (40% of the patients), a change in pulse by 20 beats per minute or more (21%), and a decrease of 5% or more in the arterial oxygen saturation (17%). Rutherford and Fisher61 reviewed the transport of 31 critical ICU patients and reported 14 life-threatening complications. This study identified hypotension in four patients, severe respiratory distress in another four patients including an extubation, disconnection of central lines in three patients, and treatment for ventricular dysrhythmias in two patients. Szem and coworkers1 identified an overall occurrence rate of complications of 5.9% in a study of 203 surgical ICU patient transports. A total of 12 complications included: marked hypoxemia (4), cardiac arrest (3), hypotension (2), cerebral infarction (1), pneumothorax requiring chest tube placement (1), and rupture of an infected arteriovenous fistula (1). Waddell62 identified three transport-related deaths in a study of 86 intrahospital transports, with an overall complication rate of 8.1%. Complications seen were hypotension (3), cardiopulmonary arrest (1), airway obstruction (1), hypertension (1), and rebleeding from a pelvic fracture (1).

Responsibilities of the Attending Physician

Any decision to transport a critical patient within a facility necessitates careful consideration. Physicians who transfer patients to other facilities generally understand the importance and responsibility of reviewing the risks and benefits of each transfer with a patient (or their designee). Similarly, physicians are also familiar with their obligation to explain the risks and benefits and obtain an informed consent prior to procedures or diagnostic testing. However, the risk of intrafacility transport may not be considered with the same significance or may be overlooked altogether.

With advances in medical technology, more diagnostic and therapeutic options can be brought to the ICU bedside, avoiding inherent risks of intrahospital transport. Bedside ultrasonography may provide valuable information, avoiding transport to a CT scanner. Some surgical procedures may also be done at the bedside. A percutaneous dilational tracheostomy can provide for a long-term airway while avoiding transport to the operating room. A bedside diagnostic peritoneal lavage or focused abdominal sonography for trauma (FAST exam) may avert the need for abdominal imaging.

The need for transport is best weighed against the outcome of the test and how it would impact patient care. If a positive or negative test will result in a timely change in therapy, the transport may be justified. However, if no immediate change is anticipated based on the results, or if the transport is considered high risk, then the transport is best avoided. Numerous studies have examined the impact of diagnostic testing outside of the ICU and its influence on patient management. Indeck and colleagues60 evaluated 103 patient transports for radiographic tests and identified 113 physiologic complications. Only 24% of these transports resulted in therapeutic changes within 48 hours. In a study by Hurst and associates,63 66% of the ICU patients who were transported experienced physiologic deterioration, while only 39% of these transports yielded a change in patient management.

Coordination of the Intrahospital Transport

Hospitalwide guidelines for the transport of patients within the facility can greatly assist in assuring patient safety for transport. Proper planning, training, and equipment minimizes risk. Communication and coordination are keys to the success of a safe intrahospital transport. Hospital security, transport personnel, or ancillary staff should be available to secure elevators as needed. Prior to departing the ICU, ED, or other point of origin, notification given to the destination (e.g., radiology, operating room, etc) will verify the availability to immediately accept the patient upon arrival. If multiple diagnostic studies are required, it may be preferable to undertake one prolonged trip outside the unit rather than several shorter trips. An immediate review of diagnostic studies is also beneficial to facilitate additional films or procedures as needed, while avoiding a second transport.

Transport Decision Making

In the ideal situation, a dedicated in-hospital transport team with dedicated monitoring equipment and routine medications for resuscitation, intubation, and sedation provides intrafacility transfers. The reality, however, is that in most situations the physicians and nurses managing the patient will need to anticipate patient care requirements during transport to determine the qualified personnel and transport equipment that will be necessary for safety. Except for the vehicle-related considerations found in the decision making for interhospital transport, the process is similar for in-house transport: evaluate the patient, evaluate the medical care required, assess for special requirements (equipment and medication), and consider the personnel (availability, critical care capabilities, and training).

Medical Personnel for Intrahospital Transport

In 1993, the Transfer Guidelines Task Force Committee of the Society of Critical Care Medicine, the American College of Critical Care Medicine, and the American Association of Critical Care Nurses recommended that all critical care transports, both intrahospital and interhospital, should be performed by dedicated, specially trained transport teams. While some hospitals have developed dedicated in-house (intrafacility) critical care transport teams, other facilities are utilizing specially trained ICU or ED transport personnel. Similarly to their interhospital counterparts, these individuals have the training and experience for the transport environment, and have the clinical capabilities, transport equipment, and medications to perform these necessary and often complicated transports efficiently and safely. The use of these specialty teams can prevent many transport-related complications, improve patient flow, and reduce delays.64 Unit-based ICU or ED nurses can remain on their units to continue care for their other patients rather than transporting patients throughout the hospital.

Whether or not a dedicated transport team exists, developing hospital policies and procedures helps to identify what constitutes an appropriate level of transport personnel. The guidelines developed by the Transfer Guidelines Task Force recommend that all transported critically ill patients be accompanied by a minimum of two people, one of whom should be a critical care nurse. They suggest that an accompanying physician is necessary only for unstable patients. Many teaching hospitals will use the patient's primary nurse and a resident physician. The transport may also use a combination of the primary nurse, one or more patient transporters, and a respiratory therapist. Even when the primary providers accompany the patient, it is advantageous for them to have formal transport-related training in order to avoid unnecessary risk to the patient.

Physicians are more often present than for interfacility transport. Smith and associates reported that a physician was present during 40% of the transports, using varied transport personnel depending on the severity of illness.65 Szem and colleagues followed a standard regimen for transports, regardless of severity of illness, and had a physician present on every transport.1 These researchers felt that this was an important contributing factor in their low number (5.9%) of transport-related complications. Smith and coworkers65 on the other hand reported that one third of 125 transports sustained at least one mishap.