Anesthesia for Primary Survey

PRIMARY SURVEY

Airway

Increasingly, emergency medical technician– paramedics and flight nurses are trained to intu-bate patients in the prehospital environment. More providers capable of airway management in the critically ill or injured patient are now available to intervene in the hospital setting as well. As a result, the anesthesiologist’s role in providing initial trauma resuscitation has diminished in North America. This also means that when called upon to assist in airway management in the emergency department, anes-thesia providers must expect a challenging airway, as routine airway management techniques likely have already proved unsuccessful.

There are three important aspects of airway management in the initial evaluation of a trauma patient: (1) the need for basic life support; (2) the presumed presence of a cervical spinal cord injuryuntil proven otherwise; and (3) the potential for failed tracheal intubation. Effective basic life support prevents hypoxia and hypercapnia from contributing to the patient’s depressed level of consciousness. When hypercarbia produces a depressed level of consciousness,  basic  airway  interventions  oftenlessen  the  need  for  endotracheal  intubation  asarterial  carbon  dioxide levels return  to normal.

Finally, all trauma patients should be pre-sumed to have “full” stomachs and an increased risk for pulmonary aspiration of gastric contents. Assisted ventilation should be performed with vol-umes sufficient to provide chest rise. Some clinicians will apply cricoid pressure, although the efficacy of this maneuver is controversial.

Cervical spine injury is presumed in any trauma patient complaining of neck pain, orwith any significant head injury, neurological signs or symptoms suggestive of cervical spine injury, or intoxication or loss of consciousness. The applica-tion of a cervical collar (“C-collar”) before trans-port to protect the cervical spinal cord will limit the degree of cervical extension that is ordinarily expected for direct laryngoscopy and tracheal intu-bation. Alternative devices (eg, videolaryngoscopes, fiberoptic bronchoscopes) should be immediately available. The front portion of the C-collar can be removed to facilitate tracheal intubation as long as the head and neck are maintained in neutral posi-tion by a designated assistant maintaining manual in-line stabilization.

Alternative devices for airway management (eg, esophageal–tracheal Combitube, King supra-laryngeal device) may be used if direct laryngos-copy has failed, or in the prehospital environment. These devices, blindly placed into the airway, isolate the glottic opening between a large inflatable cuff positioned at the base of the tongue and a distal cuff that most likely rests in the proximal esopha-gus (Figure 39–1). The prolonged presence of these devices in the airway has been associated with glos-sal engorgement resulting from the large, proximal cuff obstructing venous outflow from the tongue, and in some cases, tongue engorgement has been sufficiently severe to warrant tracheostomy prior to their removal. There is limited evidence that pre-hospital airway management in trauma patients improves patient outcomes; however, failed tracheal intubation in the prehospital environment certainly exposes patients to significant morbidity.

Airway management of the trauma patient is uneventful in most circumstances, and

cricothyroidotomy or tracheostomy is rarely required to secure the trauma airway. When trauma significantly alters or distorts the facial or upper airway anatomy to the point of impeding adequate mask ventilation, or when hemorrhage into the air-way precludes the patient from lying supine, elective cricothyroidotomy or tracheostomy should be con-sidered before any attempts are made to anesthetize or administer neuromuscular blocking agents to the patient for orotracheal intubation.

Breathing

In the multiple-injury patient, providers should maintain a high level of suspicionfor pulmonary injury that could evolve into a ten-sion pneumothorax when mechanical ventilation is initiated. Attention must be paid to peak inspi-ratory pressure and tidal volumes throughout the initial resuscitation. Pulmonary injury may not be immediately apparent upon the patient’s arrival at the hospital, and abrupt cardiovascular collapse shortly after instituting mechanical ventilation may announce the presence of a pneumothorax. This should be managed by disconnecting the patient from mechanical ventilation and performing bilat-eral needle thoracostomy (accomplished by insert-ing a 14-gauge intravenous catheter into the second interspace in the midclavicular line), and then by thoracostomy tube insertion. Inspired oxygen con-centrations of 100% are used routinely in this early phase of resuscitation.

Circulation

During the primary trauma patient survey, signs of a pulse and blood pressure are sought. Unless the trauma patient arrives at the hospital other than by ambulance, the resuscitation team will likely have received information about the patient’s vital signs from the prehospital personnel (emergency medi-cal technicians, flight nurses). The absence of a pulse following trauma is associated with dismal chances of survival. The ACS Committee on Trauma no lon-ger endorses the use of emergency thoracotomy in treating patients without blood pressure or palpable pulse following blunt trauma, even in the presence of organized cardiac activity, given the lack of evidence supporting survival following this intervention.Retrospective review of emergency thoracotomy in Europe failed to demonstrate resuscitation benefit of this procedure following either blunt or penetrating trauma in the setting of cardiac arrest. In the setting of chest trauma without detectable blood pressure or palpable pulse, current practice supports reserving resuscitative thoracotomy for patients who experi-ence penetrating trauma and have preserved, orga-nized cardiac rhythms or other signs of life.

In light of these recommendations, prompt placement of bilateral chest tubes and adminis-tration of a 500–1000 mL fluid bolus should be implemented in the pulseless victim of penetrating trauma. If return of spontaneous circulation does not occur promptly, more aggressive interventions are not indicated and resuscitation efforts can be terminated.

Neurological Function

Once the presence of circulation is confirmed, a brief neurological examination is conducted. Level of con-sciousness, pupillary size and reaction, lateralizing signs suggesting intracranial or extracranial inju-ries, and indications of spinal cord injury are quickly evaluated. As noted earlier, hypercarbia often causes depressed neurological responsiveness following trauma; it is effectively corrected with basic life sup-port interventions. Additional causes of depressed neurological function—eg, alcohol intoxication, effects of illicit or prescribed medications, hypogly-cemia, hypoperfusion, or brain or spinal injury— must also be addressed. Mechanisms of injury must be considered as well as exclusion of other factors in determining the risk for central nervous system trauma. Persistently depressed levels of conscious-ness should be considered a result of central nervous system injury until disproved by diagnostic studies.

Injury Assessment:Minimizing Risks of Exposure

The patient must be fully exposed and examined in order to adequately assess the extent of injury, and this physical exposure increases the risk of hypo-thermia. The presence of shock and intravenous fluid therapy also place the trauma patient at great risk for developing hypothermia. As a result, the resuscitation bay must be maintained at near body temperature, all fluids should be warmed during administration, and the use of forced air patient warmers, either below or covering the patient, should be utilized.