History of Medical Transportation

Prior to the 1600s, several methods of moving the debilitated were in use around the world. In what would become the United States, Native Americans used the travois (Fig. 4-1), which was essentially a stretcher affixed at one end to a horse or large dog to pull as a conveyance for material or disabled people. In Egypt, camel stretchers called panniers, which were used in many regions around the world with other beasts of burden such as mules, were the method of choice, even through the Napoleonic period, to move the nonambulatory.

In the fifteenth century, King Ferdinand and Queen Isabella of Spain were instrumental in the deployment of ambulancia (mobile field hospitals) to provide rapid medical aid to their soldiers. In January 1777, George Washington instructed the army’s Hospital Department Director General, Dr. John Cochran, to consult with another well-known physician of the day and his successor, Dr. William Shippen, to reorganize the medical system, including the flying hospitals, to accompany his armies in the field. Flying hospitals were equivalent to today’s MASH units (mobile army surgical hospitals). They were semitransient field hospitals that were moved with the regiment or divisional army, providing immediate care to those wounded after a battle and to those who were ill.

The next significant development of U.S. emergency medical services (EMS) and medical transport took place during the Civil War (1861-1865). The Union Medical Department implemented the use of committed, customized horse-drawn wagons as ambulances (Fig. 4-2A) as well as stretcher litters and pack animal cacolets (see Fig. 4-2B). In addition, a dedicated group of stretcher bearers and ambulance wagon attendants and drivers was formed. They received specialized training by the medical department and a tiered transport system was developed. On March 11, 1864, President Lincoln signed a law that was passed by Congress, “An Act to Establish a Uniform System of Ambulances in the Armies of the United States.” This legislation established a standardized system of ambulance service throughout the military. The law also mandated the use of special uniforms for the ambulance corps and special signs for the ambulances. Regulations issued during the war by both sides, and incorporated into this law, also conventionalized specific insignia and signage for the recognition of ambulances and hospitals.

In addition to litters, cacolets, and wagons, trains and boats were also used as medical transportation vehicles on a regular basis. Ambulance wagons took the wounded and sick from field hospitals to trains or hospital ships instead of directly to the general hospital. This would occur if the general hospital was too far to allow for reasonable transport by wagon, train, or ship. Thus, a stratified system of medical transport and transport vehicles developed.

The first civilian-manufactured ambulance in the United States, a specialized medical transport vehicle, was built in 1890 by the Hess-Eisenhardt Company of Cincinnati, Ohio. It was a horse-drawn wagon specifically designed to move the incapacitated in need of medical care. Shortly thereafter, the first motorized ambulance was made in Chicago and donated to the Michael Reese Hospital by five local businessmen in 1899. This was quickly followed by St. Vincent’s Hospital of New York, which began operating an automobile ambulance in 1900. In 1910, the first known aircraft ambulance, a plane modified to carry a patient lying down, was built in North Carolina and tested in Florida. It failed shortly following take-off and crashed after flying only 400 yards in Fort Barrancas, Florida. By 1929, the U.S. Army Air Corps had been organized and designed three planes to perform as ambulances. They were built and equipped to carry two patients on stretchers, a pilot, and an attendant.

World War II, the Korean Conflict, and the Vietnam War all brought advances in trauma medicine to the military, which were then used in the civilian sector. Some improvements in military EMS organization and operations occurred; the most noteworthy was the use of helicopters to retrieve critically injured patients rapidly from the battlefield, transporting them to field hospitals (MASH units). Reducing the time from injury to surgical intervention, with on-scene advanced medical treatment such as the administration of IV fluids by nonphysicians, marked a milestone in the progression of clinical care.

A convergence of several landmark events occurred in the mid-1960s that altered the foundations of EMS in the United States, commencing a new era of modernity and organization. For decades, a crescendo had been building regarding the carnage experienced from automobile accidents on the nation’s highways. Finally, in 1961, President John F. Kennedy noted that traffic accidents were one of the greatest of the nation’s public health problems. Instantly, a new focus was established on the need for emergency medical aid for motor vehicle accident (MVA) victims.

Several crucial events took place during President Johnson’s administration. First, in 1965, Medicare was created by an act of Congress. In the original legislation, ambulance transportation was recognized as a covered beneficiary service. In so doing, the federal government established a long-term funding mechanism for EMS and medical transportation. The introduction and propagation of prehospital medical care, especially advanced clinical treatment, would not wait for government regulations. Often with no legislation regarding their activities, U.S. physicians were spearheading the use of medications, defibrillators, and other advanced medical treatment modalities in the field, at the scene of incipient need. Most of these services started with a single-minded focus of cardiac emergencies, but rapidly expanded into treating other medically urgent conditions. The emphasis was shifting from the rapid recovery and transport of victims to the rapid response of specialized personnel and apparatus, and the stabilization of patients before movement to a hospital.

The first advanced life support ambulance in the United States was used by St. Vincent’s Hospital in New York. The first nonphysician, mobile, advanced medical treatment service in America began in Miami in 1968. Dr. Eugene Nagel blended the training of surrogate quasiphysicians with radiotechnology to devise the concept of a paramedic using telemetry communication to receive real-time medical commands from a physician at the hospital. This service was followed shortly thereafter by similar programs in Columbus, Ohio, Jacksonville, Florida, Seattle, and Los Angeles. By the end of the 1970s, EMS was firmly established in the medical infrastructure of the United States as its own discipline, with its own science. During the next several decades, it would become more sophisticated, evolving into an industry.

Types of Transport

• Severe injuries are those that are an immediate threat to life because they interfere with vital physiologic functions. These severe injuries make up approximately 5% of all patient injuries, but represent more than 50% of all trauma deaths.

• Urgent injuries constitute 10% to 15% of all injuries and are not an immediate threat to life. These patients will usually require surgical intervention, but they have stable vital signs.

• Nonurgent injuries account for the remaining 80% of all trauma cases. These do not constitute an immediate threat to life. These patients will generally require medical or surgical intervention after significant evaluation and/or observation.

Assessment Principles

These principles are involved in the initial assessment of a patient with major trauma and have been outlined by the American College of Surgeons (ACS) in their guidelines regarding ATLS protocols.⁴³ These principles are as follows:

Airway maintenance with cervical spine protection

Breathing and ventilation

Circulation with hemorrhage control

Disability—neurologic status

Exposure, environmental control: Undressing the patient but preventing hypothermia

Airway Maintenance with Cervical Spine Control

On initial evaluation, ascertaining patency of the airway is of the highest priority. The perfusion of the brain and other vital structures will mean the difference between life and death, or permanent disability. Maintaining oxygenation and preventing hypercarbia are critical, especially for patients who have sustained head trauma. In a practical way, in a nonintubated patient, asking brief questions will lead to a quick evaluation of the airway and neurologic status. If the patient can talk, the airway is often patent. This assessment has to be repeated constantly.

The airway is especially critical in the head and/or maxillofacial trauma patient. The causes of upper airway compromise in the trauma patient may be tongue position, aspiration of foreign bodies, regurgitation of stomach contents, or facial, mandibular, tracheal and/or laryngeal fractures, bleeding, a retropharyngeal hematoma resulting from cervical spine fractures. or traumatic brain injury.¹³ Any laceration to the neck is classified according to the anatomic level and aggressively explored. Placement of a surgical airway may be necessary if endotracheal intubation is not possible.

A patent airway must be established while still protecting the cervical spine. A jaw thrust or chin lift procedure can be used to accomplish this. The jaw thrust maneuver involves the placement of the fingers of both hands on the angle of the mandible and the thumbs over the teeth or chin. The mandible is then gently pulled forward and rotated inferiorly. The elbow may be placed on the surface next to the patient to assist with stability. This procedure is the safest method of jaw manipulation in a patient with a suspected cervical spine injury. However, it does necessitate the use of both hands, and assistance is required to remove debris from the airway.

A chin lift procedure may be performed by placing the thumb over the incisal edge of the mandibular anterior teeth and wrapping the fingers tightly around the symphysis of the mandible. The chin is then gently lifted anteriorly and the mouth opened, if possible. Care should be taken not to extend the neck while the other hand should be used to clear any debris from the oral cavity.

Tonsillar suction should also be used to clear any secretions or other accumulations from the pharynx. A nasogastric tube or soft suction catheter may be used in patients without suspected substantial midface fractures or cranial base fractures because these tubes can be inadvertently passed into the cranial vault. An oral or nasal airway should be placed to keep the airway patent and the tongue elevated off the posterior pharynx. A nasal airway is better tolerated in an awake patient.

Any patient with multisystem trauma, altered level of consciousness, or blunt trauma above the clavicle should be assumed to have a cervical spine injury. Hyperextension or hyperflexion of the patient’s neck during airway establishment should be avoided. Excessive movement can turn a cervical spine injury without neuronal damage into neuronal deficit or even paralysis. In a multiple trauma patient with an altered level of consciousness, or any injury above the clavicle, the cervical spine (C-spine) has to be protected and stabilized. The presence of distracting injuries may deflect the attention to the C-spine; usually, a cervical collar is placed until the C-spine could be cleared. If during the placement of a definitive airway, the cervical collar has to be removed, another trauma team member will hold the head and neck to provide temporary stabilization. The cervical spine can be maintained in a neutral position using a backboard, bindings, and purpose built head immobilizers. The use of soft or semirigid collars is discouraged because they only stabilize 50% of movement. Cervical spine control should be maintained in a patient with suspected cervical spine injury until it can be ruled out clinically and/or radiographically during the secondary survey. Patients with severe head injury and an altered level of consciousness because of alcohol or drugs, or with a Glasgow Coma Score (GCS) of 8 or less, usually require the placement of a definitive airway with C-spine protection.

A patient who does not demonstrate purposeful motor responses or a patient who is combative often requires definitive airway management, with placement of an airway cuffed tube in the trachea and the tube connected to some form of oxygen ventilatory system. All airway management equipment should always be taped in place.

Breathing

Once a patent airway is verified or established, pulmonary function should be assessed. Adequate exchange of gas is required for oxygenation and elimination of carbon dioxide. Gas exchange necessitates adequate ventilation. The lungs, chest wall, and diaphragm must all function adequately to ensure proper ventilation.

Breathing evaluation is most readily accomplished by visual inspection and palpation of thoracic cage movement and auscultation of gas entry. The patient is assessed for inequalities in chest movement from one side to the other, crepitus, and local movement asymmetry, as in paradoxic thoracic cage movement in flail chest. A trained provider should also be evaluating the patient for signs of impending respiratory failure, such as uncoordinated thoracic cage and abdominal wall movement, accessory muscle use, and stridor.

Inadequate ventilation may result in hypoxemia, hypercarbia, cyanosis, depressed level of consciousness, bradycardia, tachycardia, hypertension, and/or hypotension. As a general rule, until stability has been ensured, one should administer high-flow oxygen by mask to all patients to abrogate the potential for hypoxemia.

If the patient is breathing spontaneously and ventilation is adequate, supplemental oxygen can be administered by face mask. Assisted ventilation has to be instituted if opening of the airway does not result in spontaneous ventilation. Compromised ventilation could be the result of airway obstruction, altered mechanics, or CNS depression.

The exchange of air does not guarantee adequate ventilation. There are injuries that may impair ventilation, causing an obstructive or mechanical impairment. For example, a patient with a pneumothorax, flail chest, or hemothorax may have a chest wall that moves but ventilation may still be inadequate. In addition, shallow breaths or slow rates may not allow for adequate ventilation. Very slow and rapid rates of respiration suggest poor ventilation. Older patients with pulmonary dysfunction fall into a group with an increased risk of developing mechanical pulmonary problems.

A patient’s respiratory status should be monitored constantly. Signs of ventilator deterioration warrant placement of a secured airway via an endotracheal tube or the initiation of assisted ventilation. At this point, a patient can be artificially ventilated by a bag-valve mask or a bag attached to an endotracheal tube. Patients who require assisted positive-pressure ventilation with an Ambu-Bag or mechanical ventilator should be closely monitored if their chest status has not been completely evaluated. A simple pneumothorax can be converted into a tension pneumothorax when the intrathoracic pressure increases (Fig. 4-7). In the presence of a pneumothorax, especially a tension pneumothorax, immediate treatment with a regular chest tube or needle insertion is necessary.

During the primary survey, the chest should be fully exposed and inspected for any signs of obvious injury. Presence of bruising, flail chest, penetration, and bleeding should be noted. The chest should be palpated for signs of rib or sternal fractures. Any subcutaneous emphysema should be appreciated. The neck should be evaluated for any sign of tracheal deviation and jugular venous distention. Chest expansion should be equal bilaterally, without intercostal or supraclavicular muscle retractions during respiration. The breathing rate should be assessed for signs of abnormality, such as tachypnea. Tachypnea with shallow respirations is suggestive of chest injury and impeding hypoxia. Distant heart sounds and distention of the neck veins can be suggestive of cardiac tamponade. If any of these conditions is suspected, before or after intubation and initial ventilation, a chest x-ray would be mandatory.

Head injuries may result in abnormal breathing patterns that could alter normal ventilation. Spinal cord injuries at the level of the cervical spine may affect normal muscle function and therefore compromise oxygen demands. Complete cervical transection at the C3 and C4 levels will compromise the phrenic nerves, resulting in abdominal breathing and paralysis of the intercostal muscles.

Standard monitors with a capnometer and pulse oximeter ensure adequate ventilation evaluation. Remember that the pulse oximeter does not measure the partial pressure of oxygen (PaO₂) and, according to the position of the oxyhemoglobin dissociation curve, the PaO₂ could vary. The use of pulse oximetry alone cannot distinguish between oxyhemoglobin and carboxyhemoglobin or methemoglobin. This is an important consideration in patients with vasoconstriction and carbon dioxide poisoning.

Circulation Management

In the primary survey, circulation becomes the priority after airway and breathing have been definitively managed. Delivery of oxygen to the tissues is dependent on adequate circulation. The main cause of deaths that can be prevented is caused by hemorrhage. It is estimated that hemorrhage accounts for 30% to 40% of trauma mortality, with 35% to 65% of deaths occurring in the prehospital period; 50% of deaths secondary to hemorrhage occur within the first 24 hours after the initial trauma.¹⁴ In general, blood volume is 7% of body weight; in children, it is considered to be 8% to 9%. Shock in a trauma patient is primarily hypovolemic secondary to trauma, although the patient may present with cardiogenic, neurogenic, or even septic shock. There are conditions that will contribute to a shocklike tension pneumothorax by reducing venous return. Extensive damage to the CNS or spinal cord may result in a neurogenic shock. In very unusual situations, septic shock may be present if the treatment of the patient was initiated several hours after the initial trauma.

Assessment

The surgeon should be aware of the simultaneous compensatory mechanisms in a trauma patient and also the individual situation. In the older patient, for example, aging will affect general and specific organ systems that are predictive of failing health. Medically compromising conditions and the use of different medications are frequently present in this group and can contribute to high morbidity and mortality rates with relative minor injuries.¹⁷ According to the ABCs of trauma, once the airway is patent and ventilation is reestablished, the hemodynamic status (blood volume and cardiac output) should be assessed, as follows

Rapid pulse may indicate blood loss whereas an irregular pulse may indicate cardiac dysfunction. Different age categories should be taken into consideration when assessing heart rates. For example, young patients with normal vagal tone and older patients with pacemakers and/or beta blockers will have different responses to hypovolemia. The heart rate will not increase as expected.