Sunday 6 May 2012

Prehospital Trauma, Triage, and Care

Trauma Triage
Trauma triage involves the sorting of patients based on the severity of their injuries and the availability of resources. Generally, there are two different types of trauma triage used in the out-of-hospital setting.
  • Field triage involves determining if a trauma patient requires the services of a trauma center, based on an estimation of the severity of injury, or can safely be cared for at a non-trauma center. Trauma triage criteria are used in single-patient events, or events with small numbers of patients that do not exceed the capabilities of the trauma system.
    • Field triage guidelines. Knowledge of injury, mechanism, and existing co-morbid factors is key for optimal trauma triage. Unfortunately, no single factor will guarantee triage success. The following must be incorporated into the triage decision-making process: (Table 6-1)
      • Patient assessment. The initial patient survey identifies and treats immediately life-threatening injuries.
        • Abnormal physiologic signs strongly suggest the need for rapid treatment and transport to a trauma center.
        • Anatomic locations and types of injuries can predict the need for emergent surgical or specialty care.
      • Mechanism of injury. Although not as strong a predictor for the need to operate immediately or receive intensive care as the anatomic and physiologic criteria, analysis of injury mechanism at the scene can improve triage accuracy by considering the forces involved and the kinetic energy transferred during the event. When encountering a patient-meeting mechanism of injury criteria that are neither anatomic nor physiologic, pre-hospital personnel should review the case with the direct medical oversight (DMO) physician by phone or radio to choose a destination.
      • Premorbid conditions. No formal system exists for assessing or ranking premorbid conditions, yet these are included in decision making. As with mechanism of injury criteria, discussion with the DMO physician may be helpful.
    • Field triage scoring. Several trauma scoring techniques determine the severity of injury of trauma victims both in the hospital and in the field. Examples include the Trauma Score, CRAMS Scale, Prehospital Index, and Trauma Triage Rule. Accurate trauma scoring is dependent on diagnostic skills and capabilities, and thus can be limited by field conditions, patient intoxication, and compensatory physiologic mechanisms masking major injuries. Trauma scoring systems typically look at combinations of the following:
      • Cardiovascular system
      • Respiratory system
      • Central nervous system
      • Type and location of injury
      • Abdominal examination
  • Mass casualty triage involves prioritizing patients when needs exceed available resources. In situations when the number of patients and their injuries exceed the
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    resources of the field providers, transport capability, or local treatment facilities, triage is required to identify potentially salvageable patients with life-threatening conditions that require immediate treatment and transport.
    TABLE 6-1 Field Triage Guidelines
    Patient assessment
    -Physiologic: If yes, take to trauma center
    -Respiratory rate <10 or >29 breaths/min
    -Systolic blood pressure <90 mmHg
    -Glasgow Coma Scale score <14
    -Revised Trauma Score <11 (or Pediatric Trauma Score <8)
    -Anatomic: If yes, take to trauma center
    -Penetrating injuries to head, neck, torso, or extremities proximal to the elbow, or:
    -Flail chest
    -Two or more proximal long bone fractures
    -Combination trauma with burn
    -Pelvic fractures
    -Limb paralysis
    -Amputation proximal to wrist or ankle
    Mechanism of injury and high-energy impact
    -Ejection from automobile: If yes, contact medical oversight, consider transport to trauma center
    -Death of victim in the same passenger compartment
    -Extrication time >20 min
    -Fall >20
    -Rollover accident
    -High-speed vehicle crash (>40 mph, deformity >20 in, or intrusion >12 in)
    -Pedestrian thrown or run over
    -Motorcycle crash >20 mph or separation of rider from bike
    Pre- or comorbid conditions: If yes, contact medical oversight, consider transport to trauma center
    -Age <5 or >55 y
    -Cardiac or respiratory disease
    -Insulin-dependent diabetes mellitus, cirrhosis, or morbid obesity
    -Immunosuppressed
    -Pregnant
    -History of bleeding disorder or taking anticoagulants
    • Mass casualty triage is typically initiated by the first EMS personnel to arrive on scene, once scene safety is ensured and basic information regarding the incident is relayed to dispatchers so additional resources can be mobilized. The responsibility for patient triage is often delegated to more experienced personnel when they arrive. Field triage works best when victims are limited to a small geographic area. Large disaster sites (such as earthquakes and floods) or disasters with geographically distinct areas or “sides” (such as either side of a train crash, when mobility between and access to the two sides is limited by the wreckage) can require multiple triage sites.
    • While it is generally taught that the most critically injured patients are transported first, empiric data are lacking to support this principle. Triage is a continuous process, with frequent reassessment of patient status and resources. Patients are typically retriaged on arrival at the hospital.
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    • Simple Triage and Rapid Treatment (START) is the most commonly used mass casualty triage system in the United States. Patients who are ambulatory are first removed from the area. Remaining patients are classified as “expectant” if obviously dead or if not breathing after one attempt to reposition the airway. Remaining patients are categorized as “immediate” or “delayed,” based on the evaluation of respiratory rate, perfusion, and mental status. An abnormality in any one parameter places the victim in the “immediate” category.
    • Triage tags are often used to identify needs in both large and small multivic-tim incidents.
      • Problems that can occur with triage tags include:
        • Separation of the tag from the victim
        • Contamination by blood or body fluids
        • Limited space for documentation
        • Inability to “upgrade” a patient's triage categorization, since many tags use color-coded strips that are torn off (leaving the patient's categorization attached) and cannot be reattached if a patient's status worsens
      • Color codes are traditionally used to identify patient categorization by injury severity and need for transport:
        • Red = “immediate” or most critically injured. Includes patients with major injuries to the head, thorax, and abdomen for which immediate surgical or specialty care is required.
        • Yellow = “delayed” or less critically injured. Includes patients who are less seriously injured, who still likely require in-hospital treatment, but whose clinical condition permits a delay of this treatment without endangering life.
        • Green = “ambulatory” with no life- or limb-threatening injury identified. Ideally, all of the ambulatory patients who are initially moved away from the disaster scene will be reassessed by medical personnel to identify injuries.
        • Black = “expectant” or dead. Patients who would be triaged to “red” under certain circumstances might be triaged to “black” when resources are more limited to optimize resource use.
    • Limitations to triage Perfect triage is difficult to achieve for a variety of reasons. In field triage and mass casualty events, over- and under-triage may occur.
      • Over-triage (false positives) occurs when a patient who does not require a trauma center or high level of immediate care is transported to a trauma center. When resources are not constrained, this is not a problem aside from some degree of resource waste if activation of teams unnecessarily occurs. In a mass casualty situation, overtriage may limit the ability of a trauma center to provide optimal care for those who need it.
      • Under-triage (false negatives) occurs when a patient who may benefit from trauma center/higher level of care is transported to a non-trauma/less capable center. This can impact ultimate outcomes, either in the single-patient or multiple-patient setting. In a mass casualty incident, undertriage may be unavoidable as trauma centers become saturated.
      • Due to the balance between sensitivity (which considers false negatives) and specificity (which considers false positives) of any diagnostic test, increases in over-triage are needed to reduce under-triage. While it is commonly stated that 50% over-triage is acceptable to achieve 10% undertriage, there are no outcome data nor formal consensus for these figures.
II. Traumatic Arrest
The term “traumatic arrest” refers to the end result of a variety of pathologic processes in response to injury and is not a single clinical entity.
A. Etiology
EMS personnel should be trained to recognize the three most common treatable causes of traumatic cardiopulmonary collapse in the prehospital setting: airway obstruction, hypoventilation or hypoxemia, and tension pneumothorax.
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  • Airway. Loss of a patient airway is a common reason for immediate car-diorespiratory collapse after trauma. The following causes must be sought and treated:
    • Occlusion by tongue or epiglottis
      • Loss of tone (head injury, hypoxia, drugs, stroke)
      • Facial fracture
      • Direct inter-oral trauma
    • Occlusion by foreign body (blood, avulsed teeth or soft tissue, emesis)
    • Direct traumatic disruption (laryngeal fracture, tracheal collapse)
  • Breathing. Even with a patent airway, inadequate gas exchange can rapidly lead to death. This can result from:
    • Loss of respiratory effort, caused by:
      • Severe head injury
      • High spinal cord disruption (phrenic nerve roots exit C2–5 to innervate the diaphragm)
      • Central nervous system (CNS) depression from toxins or drugs (including alcohol)
    • Mechanical dysfunction
      • Tension pneumothorax
      • Large or bilateral open pneumothorax (“sucking chest wound”)
      • Flail chest
      • Thoracic compression
      • Diaphragm rupture
      • Large hemothorax
    • Systemic toxins (including drugs, alcohol, and inhalation of toxic products of combustion such as carbon monoxide and cyanides)
  • Circulatory. Impaired delivery of oxygenated blood to vital organs will cause rapid clinical deterioration. This can occur from:
    • Severe hemorrhage
      • External
      • Intra-thoracic (including disruption of great vessels)
      • Intra-abdominal
      • Pelvis or retroperitoneal
      • Multiple long bones
      • Not intracranial (except possibly in children <1 year of age)
    • Obstruction of blood flow (preventing venous return to the heart)
      • Tension pneumothorax
      • Pericardial tamponade
    • Myocardial dysfunction
      • Contusion
      • Rupture
      • Infarction and ischemia
      • Dysrhythmia
        • Electrical shock
        • Commotio cordis (due to a high-energy blow to chest)
        • Hypoxemia or global ischemia (e.g., hemorrhagic shock)
B. Determination of viability
  • Likelihood of survival. The research on this topic often include a mixture of clinical conditions, making interpretation difficult. Nonetheless, all studies show a dismal prognosis. A few general guidelines can be gleaned from the available data.
    • Victims of penetrating trauma have a greater likelihood of survival from cardiac arrest than victims of blunt trauma.
      • Survival from arrest is more likely after stab wounds than after gunshot wounds.
      • Arrest before EMS arrival decreases the likelihood of survival, particularly if transport times are long.
      • Presence of recognized and quickly treated pericardial tamponade is a positive prognostic factor, but this is usually not done in the field.
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    • Victims of blunt trauma who suffer cardiopulmonary arrest have an extremely low likelihood of survival, approaching zero (unless witnessed and treated in the emergency department).
      • Those found by pre-hospital personnel to be in arrest with no signs of life (absence of spontaneous movement or respirations, and absence of reflexes including pupillary) and no electrical activity on the electrocardiogram have a negligible chance of survival. Pre-hospital resuscitation is not indicated for these patients.
      • The presence of some life sign (eye movement, pupil reaction, corneal reflex, organized cardiac rhythm) in pulseless, nonbreathing patients confers a likelihood of survival no greater than 1% to 2%. Because aggressive interventions (e.g., intubation, ventilation, release of tension pneumothorax, and volume resuscitation) result in occasional long-term survival, resuscitation is attempted. Persistence of pulselessness (especially asystole) on hospital arrival is uniformly fatal and further resuscitation is not warranted.
      • Deterioration into cardiac arrest after EMS arrival but before hospital arrival also has dismal prognosis, but full resuscitative efforts should generally be undertaken. Most data suggest no benefit to emergency department thoracotomy for prehospital blunt traumatic arrest.
C. Criteria for attempting resuscitation
Resuscitation should be attempted on patients in arrest caused by major blunt or penetrating trauma, unless one or more of the following criteria are met:
  • Injury obviously incompatible with life (e.g., decapitation, incineration)
  • Absent signs of life (no respiratory effort, no pupillary response or eye movement, no response to deep pain) and ECG rhythm of asystole
  • Documented, untreated pulselessness and apnea for >10 minutes (e.g., prolonged entrapment, hazardous scene) in a normothermic patient
  • Rigor mortis or dependent lividity
  • Transport time to an ED or trauma center of more than 15 minutes after the onset of cardiopulmonary arrest
D. Special conditions
  • Electrical shock or lightning. Because arrest is usually caused by a cardiac dysrhythmia and may be reversible, aggressive resuscitation should be attempted. In cases of multiple casualties from an electrical incident, those in arrest should be given first priority.
  • Drowning or hanging. Arrest is usually caused by asphyxia in these situations. Although appropriate trauma care, such as spinal immobilization, should be instituted, the decision to resuscitate can be based on criteria for “medical” arrests. Hypothermia should be considered in drowning victims.
  • The presence of hypothermia (core temperature <35°C) can result from or lead to a traumatic event. Hypothermia can make it difficult to detect signs of life. Patients who are severely hypothermic should generally undergo active core rewarming before cessation of resuscitative efforts unless injuries are clearly incompatible with life. Refer to Chapter 41 for more detail on this illness and treatment.
  • Arrest secondary to medical cause. Caution should be taken to recognize patients who may have suffered cardiac arrest because of a medical condition, such as the driver of an automobile who develops ventricular fibrillation with a resultant crash. Unless evidence suggests a fatal injury, patients whose mechanism of injury does not correlate with the clinical condition should typically undergo resuscitative efforts similar to any other non-traumatic arrest patient.
E. Management of traumatic arrest
  • At the scene. Time on scene (excluding extrication) should typically be <10 minutes.
    • Ensure scene safety before entry, particularly in cases involving assaults, fire, hazardous materials, confined spaces, and vehicular traffic. Law enforcement or fire service assistance may be needed to secure the
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      scene prior to EMS operations. Field personnel should not put themselves at risk for a patient with a negligible chance of survival.
    • Recognize cardiac arrest.
      • Determine whether to initiate resuscitation (see Section B).
      • Assess for the presence of special conditions such as hypothermia or a primary medical cause that might influence decision or course of resuscitation.
    • Maintain manual spinal immobilization.
    • Open airway using jaw thrust without head tilt. Inspect oral cavity, and suction or manually remove debris (blood, teeth, etc.).
    • Ventilate patient with basic techniques (e.g., bag-valve-mask) at a rate of 12 to 16 breaths/minute. Use supplemental high-flow oxygen as soon as available.
    • Perform chest compressions at rate of 100/minute.
    • Control severe external hemorrhage.
    • Determine ECG rhythm (note that above steps may be carried out while assessing rhythm to decide whether to proceed with resuscitation):
      • Defibrillate up to three times for ventricular fibrillation.
      • Note the presence of an organized rhythm (pulseless electrical activity) as this confers a greater likelihood of a reversible condition.
    • Attempt endotracheal intubation (refer to Chapter 11).
      • If able to intubate, confirm proper tube position and carefully secure tube.
      • If unable to perform intubation, determine effectiveness of ventilation using basic techniques:
        • If able to ventilate adequately (chest rise and fall), continue ventilation with basic maneuvers.
        • If unable to ventilate adequately with a mask device, and if the rescuer is properly trained and qualified, either insert an alternative airway device (e.g., Combitube or laryngeal mask airway [LMA]) or perform jet ventilation or surgical cricothyroidotomy; otherwise (as is often the case in most EMS situations), initiate rapid transport and continue to attempt ventilation with basic maneuvers.
    • Assess patient for tension pneumothorax.
      • Signs: unilateral (or bilateral) decreased breath sounds, poor or worsening lung compliance (especially with positive pressure ventilation), tracheal deviation, subcutaneous emphysema.
      • If pneumothorax is suspected, perform needle decompression.
    • Immobilize the patient's spine on long backboard with straps, rigid cervical collar, and head immobilization device.
    • Transfer the patient rapidly to the vehicle, and initiate transport.
  • En route to the hospital
    • Ensure ongoing optimal ventilation (using means above, ensuring tube position if present).
    • Reassess for tension pneumothorax.
    • Contact direct medical oversight and/or receiving facility, based on local protocol.
    • Initiate intravenous (IV) access, or intraosseous (IO) access if intravenous access cannot be obtained and the rescuer is qualified.
      • Two large-bore IV lines (≥16 gauge) are optimal.
      • The role of fluid resuscitation is controversial. A pragmatic approach is to guide EMS providers to control any external hemorrhage first, and provide isotonic crystalloid fluid to help approach normal circulating volume but not to seek “normal” vital signs until hemorrhage is controlled. In many cases, the latter cannot occur until after hospital arrival.
  • Advanced interventions for physicians and other advanced providers may be indicated in some situations, especially when transport time is >15 to 20 minutes, or there is prolonged entrapment:
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    • Surgical airway
      • Cricothyroidotomy
      • Translaryngeal jet ventilation
    • Venous access
      • Central vein access
      • Cutdown of saphenous vein at groin or ankle
    • Tube thoracostomy Needle decompression can produce inadequate or only temporary decompression of pneumothorax and is inadequate for drainage of hemothorax.
  • Termination of efforts. Termination of resuscitation efforts should be considered for traumatic arrest patients with 15 minutes of unsuccessful resuscitation efforts and cardiopulmonary resuscitation (CPR).
III. Nonarrest Prehospital Trauma Management
A. Airway management
  • Introduction. While it has traditionally been taught that airway management is the most important skill to be mastered by EMS personnel, and endotra-cheal intubation the most desirable method for those near or in extremis, there are conflicting data on outcomes and intubation attempts by paramedics. Regardless, conditions and circumstances encountered by EMS personnel contribute to the challenge of establishing an airway. These include adverse environmental conditions (rain, snow, darkness); limited patient access (entrapment); limited numbers of personnel (often only two providers, only one of whom is trained in advanced airway management techniques); concern for cervical spine injury (precluding or complicating certain airway maneuvers); and patients with full stomachs, head injury, or acute intoxication (each of which can increase complication rates).
  • Patient assessment. The airway is assessed by simultaneous evaluation of several simple clinical features. These include level of consciousness, physical findings, and vital signs.
    • Level of consciousness. The patient's general condition of wakefulness is the best predictor of the ability to protect the airway from aspiration or occlusion. Specific simple features are commonly sought using the AVPU scale: Is the patient awake, eyes open, and conversing? Is the patient reacting to verbal stimuli? Is the patient arousable only to painful or noxious stimuli? Is the patient unresponsive? Abnormalities of mental status can be caused by hypoventilation, hypoxemia, hypoperfusion, drug or alcohol intoxication, or head injury. If the patient's ability to maintain adequate oxygenation, ventilation, or airway patency is impaired, airway interventions are required.
    • Physical findings. Search for findings indicative of poor oxygen delivery to tissues: pale, cool, moist skin; delayed capillary refill (>2 seconds); noisy or labored respirations (too fast or too slow). Other physical findings more specific to a pure respiratory abnormality include asymmetric or shallow chest excursion, crepitus, thoracic ecchymosis, nasal flaring, accessory muscle use, abdominal breathing, or subcostal retraction.
    • Vital signs. Abnormal vital signs (including pulse oximetry) must be addressed and appropriate therapy instituted. Normal vital signs do not guarantee adequate ventilation or airway protection.
  • Airway resuscitation encompasses positioning and clearing the airway, delivering supplemental oxygen, using adjuncts or assist devices, and implementing tracheal intubation techniques.
    • Positioning the airway. Manual techniques for opening the airway include the head tilt/chin lift, jaw thrust, and jaw lift. Each acts to manually displace oropharyngeal soft tissues and the tongue away from the posterior portion of the throat, allowing upper airway patency. In the trauma patient, presence of a cervical spine injury must almost always be suspected; therefore, the head tilt/chin lift is contraindicated in most trauma patients,
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      aside from those with isolated extremity injuries. The jaw thrust is accomplished by placing two hands at the angles of the mandible and lifting the jaw forward. The jaw lift is performed by placing a thumb inside the mouth on the mandibular incisors and fingers under the tip of the chin. The jaw and its attached soft tissues are then lifted forward. Semiconscious or combative patients may bite rescuers, precluding use of the jaw lift. Otherwise, when performed with cervical spine immobilization, jaw thrust and lift offer low risk and good yield for patients requiring assistance in maintaining airway patency. These maneuvers are also adjuncts for more advanced interventions, including assisted ventilation and tracheal intubation.
    • Supplemental oxygen. To maximize alveolar oxygen concentration, supplemental oxygen should be administered to all trauma patients. This can be accomplished by numerous devices. The high-flow devices, including the partial and nonrebreather masks, are best for delivering oxygen to the conscious, alert trauma patient. The fraction of inspired oxygen (FiO2) delivery by nasal cannula is variable and limited by blood or secretions in the nares. For this reason, nasal cannula oxygen supplementation should not be used in place of high-flow mask devices.
    • Airway adjuncts are devices or maneuvers that aid in maintaining airway patency.
      • Suctioning. The clearing of secretions, mucus, blood, debris, or vomi-tus is essential to establishing airway patency. Dentures, loose teeth, bone fragments, and other foreign material must be removed. Suctioning is performed with a plastic, rigid, large-opening device (e.g., a Yankauer or tonsil tip catheter) to allow rapid removal of materials without clogging of the device. Handheld pump-action devices or large-caliber suction tubing without a tip can also be used to clear the airway of debris. Care must be taken to avoid inducing or exacerbating oropharyngeal bleeding when using any suction device. Small-bore devices are not recommended for use in trauma patients.
      • Nasopharyngeal airway is a device to maintain airway patency in the semiconscious or unconscious patient. Nasal airways must be used in conjunction with manual positioning of the airway (jaw thrust or lift). The size of the patient's little finger can help guide choice of a nasal airway, and the most patent nostril should be used for insertion. The device is an uncuffed, pliable rubber tube with a beveled tip and a funnel-shaped top (hence the common nickname “nasal trumpet”). The device is inserted into the nose, and extends from the nostril to the nasopharynx, coming to rest behind the base of the tongue. Advantages of the nasopharyngeal airway are ease of insertion; aid in maintaining airway patency behind the tongue; ability for repeated suctioning without intense oropharyngeal stimulation; and usefulness in patients with a gag reflex or clenched teeth where oropharyngeal airways cannot be used. Disadvantages include inability to isolate the trachea, and obstruction by blood or secretions.
      • Oropharyngeal airway is a rigid, plastic, semicircular-shaped device with side ports that facilitate suctioning. It is used only in unconscious patients who lack a gag reflex. Oropharyngeal airways must be used in conjunction with manual positioning of the airway. The device is placed into the mouth following the curvature of the tongue (while holding the tongue with a gauze pad or using a wooden depressor) with the tip resting behind the base of the tongue. Alternatively, the airway can be inserted with the open curve of the “C” facing cephalad or lateral, with the tip then rotated to match the natural tongue curve after placement. With either placement method, pushing the tongue posteriorly will occlude the airway. The size of the oropharyngeal airway is chosen based on the distance from the lip angle to the ear lobe. In addition to maintaining or restoring airway
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        patency, the advantages of an oropharyngeal airway include ease of suctioning and assistance of ventilation. Disadvantages are stimulation of the gag reflex in the semiconscious patient, inability to place the device in patients with clenched teeth, and inability to isolate or protect the trachea.
      • Esophagotracheal Combitube (ETC) (Fig. 6-1)
        • The ETC is placed through the mouth without direct hypopharyn-geal or glottic visualization. Normally, the tip resides in the upper esophagus and hypopharynx. After inflating the balloon to obstruct the flow of gases to the esophagus, the esophageal port is ventilated. Gas exits from holes above the esophageal cuff or balloon and is directed the short distance toward the glottis, resulting in near normal tidal volumes delivered to the lungs, with attendant breath sounds and expired CO2.
        • Approximately 10% to 15% of insertion attempts result in the glottis being entered rather than the upper esophagus; resultant ventilation of the esophageal port yields lack of chest excursion or breath sounds. This must be recognized; in this situation, the second port should be ventilated. Similar to a standard endotracheal tube, this should provide direct oxygen to the trachea and produce symmetric breath sounds, CO2 on exhalation, and a quiet epigastrium. Little neck manipulation is needed with the blind insertion. The major disadvantages include lack of tracheal isolation in most cases, and the need to identify the cases in which the glottis is entered (to allow ventilation through the correct port).
      • Laryngeal mask airway (LMA) (Fig. 6-2) The LMA is a pliable, sili-cone teardrop-shaped diaphragm with an inflatable, cuffed rim and a proximal ventilation tube. The diaphragm is placed through the oropharynx and rests above the glottis, with its tip in the esophagus. The diaphragm acts to isolate the posteriorly located esophageal structures from the anterior laryngeal opening. The proximal port is ventilated using a bag-valve device. Advantages of the LMA include rapidity and ease of placement, high success rates with training, and
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        maintenance of inline cervical positioning during insertion. Its ability to prevent aspiration is controversial, particularly in patients with high airway pressures (e.g., asthma). Disadvantages include initial training requirements, little data on its use outside the operative suite or hospital, the requirement of an unconscious patient, and the necessity of “sizing” the device.
        Figure 6-1. Esophagotracheal Combitube (ETC). (Modified from the Sheridan Catheter Corporation, Argyle, NY, with permission.)
        Figure 6-2. Laryngeal mask airway (LMA). (Modified from The laryngeal mask airway: Its uses in anesthesiology. Anesthesiology 1993;79:144–183, with permission.)
      • Sellick's maneuver. Gentle manual pressure is placed on the cricoid cartilage, with the intent of occluding the esophagus that lies directly behind it. When correctly performed, cricoid pressure helps limit the risk of aspiration by impeding gastric insufflation and the movement of vomited material into the hypopharynx and glottis. It also can aid intubation by moving anterior laryngeal structures into view during laryngoscopy (e.g., backward, upward, rightward pressure, or BURP). Care must be exercised as aggressive pressure can transmit forces to the underlying cervical spine. Otherwise, this maneuver offers little risk and great potential benefit. One common mistake is to put pressure on the thyroid cartilage rather than the cricoid cartilage, which does not alter the risk of aspiration and can tilt the glottis out of view during laryngoscopy. Cricoid pressure is maintained until proper endotracheal tube position is confirmed.
    • Advanced airway skills in the field
      • All advanced airway techniques, from direct oral intubation to surgical airways, require a significant investment in training, equipment, and continuing education (to maintain competency). Each skill can be performed by physicians, paramedics, and nurses after proper training and with specific guidelines. However, it is not at all clear under what circumstances these techniques should be used, particularly in the nonarrest patient. Chapter 11 discusses general trauma airway issues; here, we highlight those specific to the prehospital setting.
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      • Endotracheal intubation. (Chapter 11 also discusses this topic.) Orotracheal intubation is the method of choice for most apneic patients, with nasotracheal intubation an alternative method in certain spontaneously breathing patients with clenched teeth or inability to open their mouths. In the field, the success rate of nasal intubation is lower than with oral intubation. Recent data strongly suggest that field intubation assisted by sedative and paralytic drugs (“rapid-sequence intubation”) is associated with worse outcomes in patients with serious head trauma than is noninvasive management with bag-valve-mask techniques. No cause-effect relationship has been established, and optimal ventilation strategies for these patients remain unknown.
      • Digital intubation may be useful when limited access to the patient or inability to directly visualize the airway structures exist. In the field, limited suction capabilities make this an attractive option for advanced providers. Digital intubation requires an unconscious patient and a “bite-block” (or other protective device) to prevent injury to the provider's fingers. The long finger of the nondominant hand is “walked” to the base of the tongue until a cartilaginous membrane (epiglottis) is encountered. While pushing the tongue downward with the long finger and elevating the epiglottis with the index finger, the endotracheal tube is guided blindly between the fingers into the glottic opening. Digital intubation has the advantage of being possible in cases where injury or foreign material limits direct visualization of the glottis. However, the technique requires dexterity, has risk of harming the provider, and causes uncertain motion of the cervical spine. There have been no organized studies of the efficacy or effectiveness of this technique.
      • Transillumination (lighted stylet) intubation. Newly developed intubation devices take advantage of fiberoptic technology to aid in tracheal intubation. A bright light introduced into the larynx will transmit through the anterior neck soft tissues to allow the operator to visualize correct stylet positioning and subsequent endotracheal intubation.
      • Percutaneous translaryngeal catheter (jet) insufflation may be useful in either failed oral or nasal intubation or in those patients with incomplete upper airway obstruction unrelieved with standard maneuvers. The relevant techniques are discussed in Chapter 11.
      • Cricothyroidotomy. Paramedics, flight nurses, and other providers can perform cricothyroidotomy for patients after failed intubation or with anatomic distortion that precludes other methods of gaining airway control. Several case studies regarding field use have been published. The techniques are discussed in Chapter 11.
    • Assist devices. Prehospital personnel provide ventilatory assistance using multiple methods.
      • Bag-valve devices. The bag-valve is an oblong, self-inflating rubber bag with two one-way valves. The bag has a standard (15 mm) connection that can attach to a face mask or endotracheal tube for ventilation. When used with room air, delivered FiO2 is 21%. High-flow oxygen at 12 to 15 liters per minute (L/min) provided by a supplemental oxygen inlet with a reservoir bag can deliver up to 90% to 95% oxygen. The bag-valve-mask device can be used to assist spontaneous respirations or to ventilate apneic patients.
      • Demand valve devices. The demand valve (manually triggered oxygen-powered breathing device) delivers 100% oxygen at high flow rates (40–60 L/min). A push-button valve allows oxygen to flow to the patient. Advantages include ease of use and high concentration of delivered oxygen. Disadvantages include lung barotrauma, inability
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        to assess lung compliance, gastric distention, and inability to use in pediatric patients. Because of these disadvantages, demand valve use is discouraged.
      • Automatic ventilators are time-cycled, constant-flow, gas-powered devices. These are small and portable, and usually have two controls—one for ventilatory rate and one for tidal volume. A standard (15 mm) adapter allows use with an endotracheal tube. While designed primarily for use in prolonged interfacility transports, some EMS systems use them in the prehospital setting.
  • Field confirmation of tracheal tube placement. Confirmation of proper endotracheal intubation is accomplished by multiple methods—no single method is infallible.
    • Physical assessment includes visualization of the vocal cords and trachea during intubation and auscultation of bilateral breath sounds in the anterior and axillary lung fields with lack of ventilatory sounds over the stomach (epigastrium). These are the first and easiest confirmatory methods for many patients, but are not definitive. Additional objective confirmation is needed.
    • End-tidal carbon dioxide detectors (ETCO2)—electronic and colorimet-ric devices—are placed between the endotracheal tube and the ventilation device. These detect end-expiratory CO2, with levels of 2% or greater indicating endotracheal placement. Semiquantitative CO22 detectors may not be accurate in low pulmonary perfusion states such as cardiac arrest, massive pulmonary emboli, severe shock, or cardiac tamponade. Outside these situations, however, expired CO2 is very useful to confirm correct tube location. All EMS systems should utilize ETCO2 detection, and any endotracheal tube placed in the field should be assessed using an ETCO2 device.
    • Bulb and suction devices, often referred to as esophageal detection devices, can be placed over the end of the endotracheal tube, creating negative expiratory pressure. These devices can be useful when ETCO2 is unavailable or when it is negative, yet the provider believes the tube is properly placed in a patient with a low- or no-flow state that may limit or prevent delivery of CO2 to the lungs. In general, these devices should not be the first-line confirmation device.
    • Pulse oximetry (oxygen saturation monitoring) is an adjunct to assess respiratory adequacy; however, arterial desaturation can be a late finding in respiratory failure. This, coupled with technical difficulties with sensing in the field, particularly with a hypotensive patient, limits the utility of pulse oximetry in rapid confirmation of tracheal tube placement, although it is valuable in identifying adequate arterial oxygenation.
B. Other procedures and therapies
  • Intravenous access and fluid therapy
    • Intravenous (IV) access allows the administration of crystalloids, blood products, and medications. Venous catheterization of trauma patients by paramedics is done routinely, even though outcome data supporting this practice are lacking. Currently, pragmatism suggests that IV access should be attempted while not delaying transport or other interventions (especially airway management and hemorrhage control). To limit the on-scene interval, attempts at IV placement should be made during extrication, while awaiting transport resources, or during transport to the hospital. Two large-bore (≥16 gauge) peripheral IV lines are preferred for major trauma patients.
    • Failures. A number of trauma patients will arrive at the hospital without IV access because of short transport times, uncooperative patients, or other more pressing priorities (e.g., airway management, spine protection, or hemorrhage control).
    • Fluid therapy in the field. Significant controversy exists regarding the composition, amount, and ultimate clinical goals of fluid therapy in trauma patients. Specific heart rate or blood pressure targets to guide the amount
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      of fluid are poorly understood. The issue does not appear to center on a “fluids: yes or no” question; rather, controlled or limited fluid resuscitation (sometimes referred to as “permissive hypotension”) appears beneficial, although the endpoint and fluid makeup are still uncertain.
  • Military antishock trousers (MAST)
    • Background. MAST, also referred to as the pneumatic antishock garment (PASG), have been in use by civilian EMS providers for many years. Their use grew out of the experiences during the Vietnam War and documented clinical effects on blood pressure in the hypotensive trauma patient. However, little positive outcome data (especially with respect to mortality or morbidity) are available to support MAST use, and they have generally fallen out of favor.
    • Effects. Several mechanisms of action are proposed for the elevated blood pressure seen with MAST inflation. The major effect is to increase peripheral vascular resistance, accomplished by decreasing the perfusion of the capillary beds of the lower extremities by the external pressure provided via the inflated MAST. This may increase blood flow to more vital organs. MAST may help stabilize pelvic and femur fractures and limit blood loss.
    • Indications. The following are current recommendations from the National Association of EMS Physicians (NAEMSP) regarding the use of MAST in trauma, using the American Heart Association's Emergency Cardiac Care “class” system:
      • Class IIa. Acceptable, uncertain efficacy, weight of evidence favors usefulness and efficacy.
        • Hypotension due to suspected pelvic fracture.
        • Severe traumatic hypotension (palpable pulse, blood pressure not obtainable)
      • Class IIb. Acceptable, uncertain efficacy, may be helpful, probably not harmful.
        • Penetrating abdominal injury.
        • Pelvic fracture without hypotension.
        • Spinal shock.
      • Class III. Inappropriate option, not indicated, may be harmful.
        • Diaphragmatic rupture.
        • Penetrating thoracic injury.
        • To splint fractures of the lower extremity.
        • Extremity trauma.
        • Abdominal evisceration.
    • Application and removal
      • Remove any objects on the patient's lower body that might cause the MAST or the patient to be punctured. The MAST are slid under the patient and the three sections secured circumferentially. (Often, the MAST are laid on the long spine board before placing the patient on it.) The leg sections are inflated first, using a foot pump. Inflation continues until the Velcro crackles or the MAST pressure gauge reads 100 mmHg. The abdominal section is then inflated in a similar manner. The patient's respiratory efforts should be observed closely because inflation of the abdominal section can limit pulmonary reserve. Large-bore suction should be available in case the patient vomits.
      • Deflating the MAST prematurely or rapidly can lead to hypotension that may not respond to reinflation of the MAST. As much as possible, the patient must be adequately volume resuscitated and/or have bleeding controlled before the device is removed. The abdominal section should be deflated first, in a slow and deliberate manner. A small quantity of air is released and the patient's blood pressure is checked. If a fall of >5 to 10 mmHg occurs in the systolic
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        blood pressure, deflation is halted. If no decrease in blood pressure ensues, deflation can proceed. Once the abdominal section is deflated, the leg sections are deflated, one at a time, in a similar fashion. Under no circumstances should the MAST be cut off a patient. This is both risky and renders the MAST unusable.
    • Complications. The most common complication of MAST use is interference with the physical examination or gaining groin vascular access. Other complications include
      • Shock after inappropriate removal
      • Compartment syndrome
      • Lactic acidosis
      • Myoglobinuria
      • Ventilatory compromise
      • Hyperkalemia
      • Increased cerebral edema
  • Needle thoracostomy
    • Indications. Needle thoracostomy should be performed when a tension pneumothorax exists or is suspected. Any trauma patient with severe respiratory distress should be evaluated immediately for tension pneumothorax. In the field, the diagnosis is critical and must be treated before arrival at the hospital. Tension pneumothorax should be suspected in the trauma patient who is short of breath or hypotensive and with any of the following features:
      • Decreased breath sounds
      • Tracheal deviation (away from the involved side)
      • Distended neck veins (this may not be seen in the patient who is hypovolemic)
      • Hyperresonance to percussion of the chest (on the involved side)—difficult to assess in the field environment.
      • If the patient is intubated, increasing difficulty in bag-valve ventilation can be the earliest or sole indication of a developing tension pneumothorax.
      • Respiratory distress
    • Procedure. Treatment should proceed rapidly once the diagnosis is suspected; if incorrect, the only harm is creating the need for a formal tube thoracostomy in the receiving facility, whereas failing to recognize and treat can lead to death. Decompress the affected side of the chest by inserting a large-bore IV catheter (12 or 14 gauge) perpendicular to the skin at the second or third intercostal space in the midclavicular line, or the third or fourth interspace in the anterior axillary line. Advance the catheter until a rush of air occurs from the open distal end, or until the hub reaches the skin. Common errors include placing the needle either too close to the sternum or cephalad to the second intercostal space (making heart or great vessel puncture possible), or placing the needle under instead of over a rib (making puncture of the neurovascular bundle, which runs in a groove under each rib, possible). After placement, withdraw the needle, but leave the catheter in place to prevent reaccumulation of pleural gas. If the patient's condition worsens, suspect occlusion of the first catheter and place a second needle (Fig. 6-3).
    • Bilateral decompression. Occasionally, especially in the patient on positive pressure ventilation or with severe obstructive lung disease, bilateral tension pneumothorax can develop. The asymmetry described above with respect to tracheal and chest findings may not be present. If uncertain, both hemithoraces should be decompressed.
    • Therapy after needle thoracostomy. At the receiving facility, a chest tube is usually placed for definitive treatment once needle decompression is performed (whether or not clinical success occurred with the latter). Once the chest tube is in place, the catheter(s) can be withdrawn.
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    Figure 6-3. Technique for needle thoracostomy. (Modified from Champion HR, Robbs JV, Trunkey DD. Trauma surgery. In: Rob and Smith's Operative Surgery. London: Butterworth, 1989:57, with permission.)
  • Splinting
    • Indications. The purposes of splinting are to prevent further injury, decrease blood loss, and limit the amount of pain the patient will have with movement of that extremity during extrication and transport. An injured extremity should be splinted in anatomic position if possible, with the splint extending to the joints above and below the fracture site for stabilization. If the patient refuses, or if resistance to straightening exists, splint in a position of comfort. Dressings should be applied to any open wounds before splinting.
    • Splint types. A large variety of splint designs will appear on patients brought to the emergency department. They can be as simple as a rolled-up newspaper, or as complex as a vacuum or traction splint:
      • Cardboard splints, with or without foam padding, are intended for single use.
      • Board splints, which are common and durable, are made of straight pieces of wood, metal, or plastic cut to various lengths.
      • Air splints, which encircle the injured extremity, are inflated with air to impart stiffness. They are usually clear to allow visualization of the underlying structures. Overinflation can cause neurovascular compromise.
      • Vacuum splints incompletely encircle the injured limb. Instead of air being blown into them, air is withdrawn and a vacuum is produced, which stiffens the splint.
      • Traction splints are used for femur fractures. Thomas half-ring splints and Hare traction splints are those most commonly used. Specific training is required for proper placement.
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      • Ladder splints are made from heavy gauge wire in a ladder shape. They are useful for splinting extremities that cannot be straightened because they are bendable and can be shaped to match the extremity. The SAM Splint, with a flexible aluminum alloy core covered with closed-cell foam, is similarly flexible.
    • Complications. Although splinting is safe and effective in most patients, complications can develop, including:
      • Neurovascular compromise. Whichever splint is used, distal neurovas-cular status must be checked before and after application of the splint. Also, if any patient movement has occurred, the patient reports more pain, or the extremity is noted to be cyanotic or edematous distal to the splint, reexamine the extremity and splint. It is also advisable to periodically check the neurovascular status, even if none of the above occur. When impaired neurovascular status is seen distal to an injury, the splint should be loosened or adjusted, and the neurovascular status rechecked.
      • Pain. When the patient reports pain, search for neurovascular compromise or malpositioning. Gentle repositioning should resolve this condition.
  • Axial spine immobilization
    • Prehospital indications. Historically, despite the lack of supporting literature, the entire axial spine is immobilized by prehospital personnel whenever the mechanism of injury, injury pattern, or physical examination indicate the possibility of any spinal injury. Most major trauma patients have experienced kinematic forces that warrant the precautionary application of spinal immobilization devices until definitive clinical and/or radiographic examinations can be performed in the ED. Patients with obvious physical findings (e.g., bony crepitation, palpable step-offs) or those with neurologic findings (e.g., paresthesia, weakness, paralysis) consistent with spine or cord injury should always receive complete immobilization before transport.
    • Clinical assessment of the spine often cannot be performed by field personnel because of time, space, distracting injury, altered consciousness, and other concerns (e.g., airway, bleeding control, vascular access) that can preclude adequate in-field evaluation to rule out spinal injury. While the rule in prehospital care is to maintain a high index of suspicion for such injuries with liberal application of spinal immobilization, it is well established that field personnel, with proper training and medical oversight, can safely assess which patients do and do not require spine immobilization. The protocols that EMS systems use for this purpose generally exclude major trauma patients from consideration for this assessment, requiring full spine immobilizing.
    • The need for spinal immobilization occurs at the injury scene and continues through extrication, transportation, and stabilization in the ED. Immobilization is accomplished with the least possible neck movement, and ends only when physical and/or radiographic findings definitively rule out injury.
    • Types of immobilization devices. No single method or combinations of methods of immobilization consistently place the spine in neutral position or prevent all motion in the axial spine.
      • Cervical collars (c-collars) are numerous in design and efficacy. These rigid one- or two-piece devices encircle the cervical spine and soft tissues of the neck, providing (when properly fitted) a snug fit between the tip the chin and the suprasternal notch of the anterior chest, and between the occiput and the suprascapular region of the back. These collars limit movement of the head in the coronal and transverse planes, minimizing lateral and rotary motion. They do not, however, provide adequate immobilization in the sagittal plane (flexion-extension motion). For this reason, a rigid cervical collar
        P.50

        alone is inadequate for effective spinal immobilization and is always used in conjunction with a cervical immobilization device (CID) and a spine board (short or long). Soft neck collars (foam supports covered with loose-weave material) are ineffective at limiting motion of the head in all planes, and are not intended for use in spinal immobilization.
      • CIDs are made of plastic, cardboard, or foam. They act to pad the lateral aspects of the head (limiting both lateral and rotary motion), and possess restraining straps that are positioned over the patient's forehead and chin, encircling the back of a short or long spine board. The CID affixes the patient's head and c-collar to a rigid spine board, limiting the head movements of flexion and extension. A CID can be fashioned from blanket rolls, blocks, or sandbags placed alongside the head, with fixation to the spine board via wide (2- to 3-inch) silk tape placed over the forehead and chin.
      • Spine boards are termed “short” or “long,” depending on the most distal portion of the patient immobilized. Short boards limit flexion and extension from the head to the hips, minimizing movement in all portions of the spine (cervical, thoracic, lumbar). Short boards are primarily used if patient access is limited (e.g., entrapment in a vehicle, or confined space extrication) and stability in the axial spine is needed before and during the extrication process. Once extrication is performed and complete access to the patient is achieved, the short board and patient are typically secured to a long spine board. Long spine boards limit flexion and extension from the head to the feet. Straps provide fixation points at the thorax, hips, and lower extremities (above the knees). Data suggest that including the lower extremities in the immobilization process aids in stabilizing the lumbosacral spine and limits lateral motion of the torso if lateral tilting of the board is needed to manage emesis. Padding between the lower extremities and under the knees enhances both stabilization and patient comfort.
        • Secondary pain after immobilization. With any of these devices, immobilization itself can produce symptoms of discomfort (e.g., occipital headache; neck, back, head, mandible pain). This should not preclude the liberal application of spinal immobilization devices in most patients with significant trauma. Padding behind the occiput and in the areas of lordosis and kyphosis make intuitive sense, and may be especially important in the pediatric and elderly population, given their anatomy.
Axioms
  • Recognizing trauma severity, assisting breathing in the simplest effective manner, controlling any bleeding, and rapidly transporting to an appropriate hospital are keys to good care.
  • Outcomes from out-of-hospital traumatic cardiac arrest are generally dismal, and each EMS system should have a protocol and procedure in place to optimally handle these difficult cases, recognizing the futility of attempting resuscitation in most such patients.
  • Effective trauma triage relies on the proficiency and accuracy of the assessment skills of field personnel.
  • The vast majority of trauma patients can be managed with basic life support skills, such as bag-valve-mask ventilation, splinting and spine immobilization, and hemorrhage control. There are no convincing data to support advanced life support interventions in trauma patients.
  • Objective confirmation of proper endotracheal tube placement, using end-tidal carbon dioxide detection supplemented by other means as needed, is mandatory for all patients intubated in the field.
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  • The differences between field triage (for individual trauma patients) and mass casualty triage (for multipatient events) must be understood by both field and hospital personnel, and EMS systems must account for these two different types of triage when establishing or refining policies and procedures.
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