Trauma: Optimizing Survival Outcomes

In a conscious patient, the airway assessment can be performed by first asking the patient a simple question (e.g., “What is your name?”). A clear, accurate response verifies the patient’s ability to mentate, phonate, and protect their airway, at least temporarily. Next, Observe the face, neck, chest and abdomen for signs of respiratory difficulty, including tachypnea, accessory or asymmetric muscle use, abnormal patterns of respiration, and stridor.

Inspect the oropharyngeal cavity for:

• Blood
• Disruption injuries to the teeth and tongue
• Pooling secretions
• Vomitus
• Note if there are any obstacles to the placement of a laryngoscope and endotracheal tube

Inspect and palpate the anterior neck for:

• Crepitus
• Hemorrhage
• Lacerations
• Swelling
• Other signs of injury

Palpation of the neck also enables the identification of the landmarks for cricothyrotomy.

The airway must be immediately protected in the unconscious patient once any obstructions (e.g., foreign body, vomitus, displaced tongue) are removed. Airway management in a trauma patient unable to protect his/her airway is completed in an expedient yet controlled fashion. When possible, a brief pre intubation assessment should be performed to gauge the potential difficulty of intubation and determine basic baseline neurologic function (e.g., pupillary light reflex, movement of extremities). The application of the LEMON mnemonic to trauma patients is described below.

L: LOOK:

Facial and neck injuries can distort external and internal structures making it difficult to visualize the glottis and insert an endotracheal tube.

E: EVALUATE 3-3-2:

These pictures refer to the intraoral, mandibular, and hyoid to thyroid notch distances.

The spatial relation ships described here are important determinates of successful direct laryngoscopy. The distance described here suggest laryngoscopy would not be difficult for this patient.

• The Patient can open his/her mouth sufficiently to admit three of his/her fingers.

• The distance between the mentum and the neck/mandible junction, near the hypoid bone, is equal to the width of three of the patient’s fingers.

• The space between the superior notch of the thyroid cartilage and the neck/mandible junction, near the hyoid bone, is equal to the width of two of the patient’s fingers.

• The cervical collar must be opened to make these assessments. The distance referred to can be narrowed by fracture, hematoma, or other anatomic distortions (e.g., soft tissue swelling)

M: MALLAMPATI:

A standard calculation of the Mallampati score cannot be performed in many trauma patients. Injured patients requiring emergency intubation often cannot open their mouths spontaneously. Nevertheless, an effort should be made to determine how much of the retropharynx can be seen and whether injuries of the oropharynx or pooled blood, vomitus, or secretions are present.

The modified Mallampati classification is a simple scoring system that relates the amount of mouth opening to the size of the tongue and provides an estimate of space available for oral intubation by direct laryngoscopy. According to the Mallampati Scale.

Class I is present when the soft palate, uvula, and pillars are visible.
Class II is when the soft palate and the uvula are visible.
Class III is when only the soft palate and base if the uvula are visible.
Class IV is when only the hard palate is visible.

O: OBSTRUCTION/OBISITY:

Either factor can interfere with visualization and management of the traumatized airway. Any number of injuries can obstruct the airway, including internal or external hematomas or soft tissue edema form smoke inhalation. Obesity complicates the performance of cricothyrotomy.

N: NECK MOBILITY:

In-line stabilization is necessary for most trauma patients. Once a second skilled provider removes the cervical collar, that provider should stabilize the spine while orotracheal intubation is performed. It is important to note that neurologic injury from hypoxemia is much greater than the risk of spinal injury due to neck extension during intubation. Judicious relaxation of immobilization may be necessary in some cases.

Several airway tools and rescue airways can be helpful when managing a trauma patient. Devices that should be available at the bedside include:

• Bag-valve mask attached to high flow oxygen
• Cricothyrotomy kit
• Endotracheal tube introducer (i.e., gum elastic bougie)
• Endotracheal tubes in a range of sizes
• Laryngoscopes, including a range of different sized blades and handles
• Oral and nasal airways
• Preferred adjunct intubating devices (e.g., lightwand)
• Rescue airways (e.g., Combitube, laryngeal mask airway)
• Suction (i.e., multiple pumps and tips)
• Video laryngoscope, if available

Direct laryngoscopy relies on direct visualization of the glottis, which is often difficult in the severely injured patient whose airway may be obstructed and whose neck cannot be manipulated. In contrast, video laryngoscopes provide an excellent view of the glottis with minimal cervical spine movement and appear to be well suited for airway management in the trauma patient. Larger studies in trauma populations are needed to confirm these initial impressions.

The endotracheal tube introducer (or gum elastic bougie) is another invaluable tool for airway management in trauma patients, particularly when the glottic view is limited.

Tracheal intubation of the injured patient is often complicated by the need to maintain cervical immobilization, the presence of obstructions such as blood, vomitus, and debris, and possibly by direct trauma to the airway. Nevertheless, many trauma patients require intubation for immediate airway protection or because of the projected disease course. Intubation improves oxygenation, thereby helping to meet increased physiologic demands and allows for testing and procedures to be performed more easily and with less patient discomfort.

Ideally, airway managers should have a predetermined backup plan with all necessary tools at the bedside, including rescue airways and a cricothyrotomy kit, before proceeding with intubation. In crash scenarios, this may not be possible. A sample checklist to assist with airway management of the adult trauma patient was provided in Table 2 above.

Clinicians should consider the expected course of the disease and the need for interventions when deciding to secure an airway. Patients often warrant early intubation to ensure airway protection or to allow for deeper sedation and pain control. Examples of this include the following:

• A patient who is hemodynamically stable for the moment but at risk of deterioration and who requires a complex diagnostic study that must be performed in a remote radiology suite.
• A patient with significant injury in imminent need of an orthopedic or other painful procedure.

Critically ill trauma patients at risk for hypotension following sedation and paralysis for intubation should be treated aggressively before intubation. Post-intubation hypotension should be anticipated and mitigated as much as possible. In a retrospective review of 444 patients, in-hospital mortality was nearly doubled for those who had a single episode of post-intubation hypotension compared with those who did not (29.8% versus 15.9%).

Clinicians who manage trauma must be prepared to perform a cricothyrotomy when orotracheal intubation cannot be accomplished. In trauma patients with a potentially difficult airway, a double set-up, simultaneous preparation is made to perform orotracheal intubation and cricothyrotomy, may be the best approach. This approach enables the clinician to transition immediately to a cricothyrotomy if attempts at oral intubation are unsuccessful. Trauma patients may have sustained injuries to the neck that make cricothyrotomy difficult to perform, and therefore, it is important to optimize any attempt at orotracheal intubation.

Once the airway and breathing are stabilized, an initial evaluation of the patient's circulatory status should be performed by palpating central pulses. If a carotid or femoral pulse is verified and no obvious exsanguinating external injury is noted, circulation may momentarily be assumed to be intact. The determination of exact blood pressure should not delay the completion of the primary survey.

While circulation is assessed, two large-bore (16 gauge or larger) IV catheters are placed, most often in the antecubital fossa of each arm, and blood is drawn for testing, particularly for blood typing and crossmatch. Intraosseous cannulation or central venous catheter placement (ideally under ultrasound guidance) can be performed if there is difficulty establishing peripheral IV access.

Life-threatening hemorrhage must be controlled. A combination of manual pressure, proximal compression with either a tourniquet or a manual blood pressure cuff, and elevation are typically sufficient to control external arterial hemorrhage. When these are unsuccessful, hemostatic agents may be used, if available. Venous bleeding is controlled with direct pressure. Bleeding from severe pelvic injuries may require the application of a pelvic binder.

Emergency thoracotomy may be needed for trauma patients without femoral or carotid pulses. The procedure is most effective for victims of stab wounds to the chest with pulses or other witnessed signs of life (e.g., voluntary movement). It is rarely beneficial in patients with blunt trauma or when performed in facilities without ready access to appropriate surgical care.

Of note, trauma patients who require cardiopulmonary resuscitation (CPR) within one hour of hospital arrival have a low survival rate to hospital discharge (only 13% in one study), so maintaining perfusion and avoiding the need for CPR is exceptionally important.

In patients in extremis with impending arrest, placement of a resuscitative balloon for occlusion of the aorta (REBOA) by those trained in this technique may be life-saving. This device is most effective in temporizing patients with intra-abdominal or retroperitoneal sources of hemorrhage until more definitive therapy with surgery or angioembolization is possible. So rapid transport to the OR and angiographic suite is essential. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is not appropriate for use in those with suspected thoracic sources of exsanguination or patients in cardiac arrest, in whom emergency department thoracotomy (EDT) should be performed instead.

Most trauma patients with hypotension or signs of shock (e.g., pale, cool, moist skin) are bleeding, and patients with severe hemorrhage have significantly higher mortality.(Table 3)

*CVP: central venous pressure

Initial fluid resuscitation for these patients may consist of a bolus of IV crystalloid (e.g., 20 mL/kg isotonic saline). However, patients with obvious severe or ongoing blood loss should be transfused immediately with type O blood (women of childbearing age should be transfused with O negative blood). While mildly unstable patients may be treated with isotonic crystalloid instead of blood, the unnecessary crystalloid infusion should be avoided.

Despite an initial fluid bolus, patients with persistent hemodynamic instability generally require blood transfusion and definitive control of the bleeding source. Significant hemorrhage occurs in any of five sites:

• External
• Intraperitoneal
• Intrathoracic
• Long bone fractures
• Pelvic fractures
• Retroperitoneal

A 1:1:1 ratio of plasma, platelets, and red cells should be targeted if transfusion is required. Patients requiring transfusion may benefit from treatment with tranexamic acid (an antifibrinolytic agent) if given within three hours of injury.

It is important to obtain manual blood pressure measurements in trauma patients with systolic blood pressures below 90 mmHg, as automated blood pressure cuffs often overestimate values significantly in these patients. Furthermore, data suggest that the traditional threshold of a systolic blood pressure below 90 mmHg to define shock is inaccurate. The appropriate systolic or mean arterial blood pressure threshold for defining shock varies by age. A significant proportion of trauma patients with hemorrhagic shock have systolic blood pressure above 90 mmHg. Using a cut-off of 110 mmHg is likely to be more appropriate in the elderly.

Some trauma patients, particularly the elderly with comorbidities, may be taking anticoagulants. Provided below are methods for reversing particular anticoagulants in cases of life-threatening bleeding.

Warfarin - Initial emergency treatment to reverse anticoagulation due to warfarin in patients with severe hemorrhage is outlined as follows:

• If 4-factor unactivated prothrombin complex concentrate (4F PCC*) is available (preferred approach):
  • Give 4F PCC 1500 to 2000 units** IV over 10 minutes.
    • Check international normalized ration (INR) 15 minutes after completion of the infusion. If INR is not ≤1.5. give an additional 4F PCC)
  • Give vitamin K*** 10 mg IV over 10 to 20 minutes.
• If 3-factor unactivated prothrombin complex concentrate (3F PCC****) is available, but 4F PCC is not available:
  • Give 3F PCC 1500 to 2000 units IV over 10 minutes.
    • Check INR 15 minutes after completion of the infusion. If INR is not ≤1.5, give an additional 3F PCC.
  • Give Factor VIIa 20 mcg/kg IV OR give FFP***** 2 units IV by rapid infusion. Factor VIIa may be preferred if volume overload is a concern.
  • Give vitamin K 10 mg IV over 10 to 20 minutes.
• If neither 3F PCC nor 4F PCC is available:
  • Give fresh frozen plasma (FFP) 2 units IV by rapid infusion.
    • Check INR 15 minutes after completion of the infusion. If INR ≥1.5, administer two additional units of FFP IV rapid infusion.
    • Repeat the process until INR ≤1.5.
    • May wish to administer loop diuretic between FFP infusions if volume overload is a concern.
  • Give Vitamin K 10 mg IV over 10 to 20 minutes.

Initial emergency treatment to reverse anticoagulation due to direct oral anticoagulants (DOC's) such as direct thrombin inhibitors (e.g., dabigatran) and factor Xa inhibitors (e.g., rivaroxaban, apixaban, edoxaban) in patients with severe hemorrhage is presented below.

Life-threatening or imminently fatal bleeding (e.g., intracranial, retroperitoneal, compartment syndrome, massive gastrointestinal).

Dabigatran (Pradaxa®)
Interventions Include:

• Idarucizumab
• Activated PCC (e.g., Factor eight inhibitor bypassing agent [FEIBA]) – use with activated PCC only if idarucizumab is unavailable
• Antifibrinolytic agent (e.g., tranexamic acid, epsilon-aminocaproic acid)
• Anticoagulant discontinuation
• Oral activated charcoal (if the last dose within the prior two hours)
• Hemodialysis
• Red blood cell (RBC transfusions if needed for anemia
• Platelet transfusions if needed for thrombocytopenia or impaired platelet function (e.g., due to aspirin)
• Surgical/endoscopic intervention if appropriate

Rivaroxaban (Xarelto®), apixaban (Eliquis®), edoxaban (Lixiana®), betrixaban (Bevyxxa®)

Possible interventions include:

• Andexanet alfa (AndexXa®) or 4-factor unactivated PPC (e.g., Kcentra®)
• Antifibrinolytic agent (e.g., tranexamic acid, epsilon-aminocaproic acid)
• Anticoagulation discontinuation
• Oral activated charcoal (if last dose recent enough)
• RBC transfusion if needed for anemia
• Platelet transfusion if needed for thrombocytopenia or impaired platelet function (e.g., due to aspirin)
• Surgical/endoscopic intervention if appropriate

Minor Bleeding (e.g., epistaxis, uncomplicated soft tissue bleeding, minor [slow] gastrointestinal bleeding).

Dabigatran (Pradaxa®)

Possible interventions include:

• Andexanet alfa (AndexXa®) or a 4-factor unactivated PCC (e.g., Kcentra®)
• Antifibrinolytic agent (e.g., tranexamic acid, epsilon-aminocaproic acid)
• Anticoagulant discontinuation
• Oral activated charcoal (if last dose recent enough)
• RBC transfusions if needed for anemia
• Platelet transfusions if needed for thrombocytopenia or impaired platelet function (e.g., due to aspirin)
• Surgical/endoscopic intervention if appropriate

Rivaroxaban (Xarelto®), apixaban (Eliquis®), edoxaban (Lixiana®), betrixaban (Bevyxxa®)

Possible interventions include:

• Local hemostatic measures
• Possible anticoagulant discontinuation
  • Half-lives (normal renal function*):
    • Rivaroxaban 5 to 9 hours
    • Apixaban 8 to 15 hours
    • Edoxaban 6 to 11 hours
• Possible antifibrinolytic agent (e.g., tranexamic acid, epsilon-aminocaproic acid)

*The anticoagulant effect of these agents (especially dabigatran) will dissipate more slowly as renal function declines. Severe hepatic failure may also prolong the half-life for rivaroxaban, apixaban, edoxaban, and betrixaban.

Heparin and low molecular weight (LMW) heprin (Hull, Garcia & Burnett, 2019)

Initial emergency treatment to reverse anticoagulation due to Heparin or LMW heparin in patients with severe hemorrhage is outlined below. The need for urgent heparin reversal is individualized according to the site and severity of bleeding and the degree of anticoagulation.

Unfractionated Heparin

Possible interventions include:

• Heparin is discontinued
  • Protamine sulfate is administered at a dose calculated based on the dose of heparin administered and the elapsed time since the last heparin dose. It is administered by slow intravenous infusion: the infusion rate should not exceed 20 mg/minute, and the total dose should not exceed 50 mg in any 10 minutes.
  • Complete neutralization of the heparin effect is achieved with a dose of 1 mg protamine sulfate/100 units of heparin. Because of the relatively short half-life of intravenously administered heparin (approximately 30 to 60 minutes), the dose of protamine sulfate is calculated by estimating the amount of heparin remaining in the plasma at the time that reversal is required. If this information is not immediately available, administration of a single dose of 25 to 50 mg can be given, and the aPTT or anti-factor Xa activity rechecked. If heparin had been given by subcutaneous injection, repeated small doses of protamine might be required because of prolonged heparin absorption from the various subcutaneous sites.
  • Protamine is a protein derived from fish sperm. Thus, it carries a small but potential risk of anaphylaxis in individuals who have previously been exposed, including diabetic patients who have received protamine-containing insulin (e.g., NPH, PZI) and individuals with fish allergy. However, unless such an allergy is known, the benefits of protamine administration to manage bleeding are likely to outweigh this potential risk greatly.
  • Boxed Warning for Protamine includes hypotension, cardiovascular collapse, non-cardiogenic pulmonary edema, catastrophic pulmonary vasoconstriction, and pulmonary hypertension for patients who have previously received protamine sulfate or other protamine-containing drugs. Patients at increased risk who are receiving protamine should be monitored closely, and access to therapies for anaphylaxis should be available. Thrombocytopenia following protamine administration has also been reported.

LMW heparin

Possible Interventions include:

• Protamine does not completely abolish the anti-Xa activity of LMW heparins. Still, it may neutralize the higher molecular weight fractions of heparin, which are thought to be most responsible for bleeding. For patients who experience bleeding while receiving LMW heparin, protamine sulfate may be used at the following doses:
  • Enoxaparin was administered in the previous eight hours: 1 mg protamine per 1 mg of enoxaparin.
  • Enoxaparin administered more than eight hours ago, or if it has been deemed that a second dose of protamine is warranted: 0.5 mg protamine per 1 mg of enoxaparin.
  • Dalteparin, tinzaparin, or nadroparin: 1 mg protamine per 100 anti-factor Xa units of LMW heparin.

In adult trauma patients, nonhemorrhagic causes of shock include cardiac tamponade and tension pneumothorax. These injuries are best detected by physical examination or ultrasound assessment (i.e., FAST). Particularly in older patients, the clinician may need to consider medical causes of hypotension that preceded and possibly caused the trauma, such as:

• Arrhythmia
• Gastrointestinal Bleeding
• Malfunctioning left ventricular assist device (LVAD)
• Malfunctioning pacemaker
• Myocardial Infarction (MI)

Inspect and palpate the entire bony structure of the head and face for tenderness, deformity (e.g., step off), and bleeding. Scalp lacerations are easily missed visually but often found by palpation. Assess for foreign bodies, such as glass in the scalp after a car accident. Note any signs suggesting basilar skull fracture:

• Hemotympanum
• Retroauricular (Battle’s sign) generally does not appear until a least 24 hours after an inury
• Periorbital ecchymosis (raccoon’s eyes) generally does not appear until at least 24 hours after an injury (Image 4)

Image 4: Raccoon’s Eyes

Image Source: Licensed from Shutterstock

Additionally, look for septal hematomas and perform an ocular examination, including evaluating pupillary size, shape, reactivity, and extraocular movement. Look for signs of globe rupture and intraocular hemorrhage. Point-of-care ultrasound can be used to rule out retinal detachment and other traumatic ocular injuries. Still, it should not be used to rule out injuries in those patients in whom a high clinical suspicion of injury exists. These patients should still receive emergency ophthalmologic consultation.

Patients with mild traumatic brain injury may not have external signs of trauma. Validated decision tools, including the New Orleans Criteria and the Canadian CT Head Rule, can be used to determine the need for neuroimaging with CT.

Assume that all patients with blunt trauma have sustained an injury to the cervical spine. This assumption can be disproved by appropriate application of clinical decision rules, such as NEXUS or the Canadian C-Spine Rule, or by radiologic evaluation using plain x-rays or CT. Inspect and palpate the entire neck for signs of injury.

Inspect and palpate the entire chest wall. Pay particular attention to the sternum and clavicles. Injuries at these sites are often missed, and fractures of these bones suggest further injury, including intrathoracic structures.

Careful auscultation can detect a previously missed small hemothorax, pneumothorax, or pericardial effusion not yet causing tamponade. The NEXUS-Chest criteria may be used to determine whether chest imaging is necessary for an adult following blunt trauma.

Inspect the abdomen and flanks for contusions, (e.g., seat belt sign), ecchymosis, and lacerations. Palpate for tenderness and rigidity. The presence of a seat belt sign, rebound tenderness, abdominal distension, or guarding all suggest intra-abdominal injury.

Keep in mind that the abdominal examination is often unreliable and can change dramatically over time, especially in:

• Elderly patients
• Patients with altered mental status
• Patients with distracting injuries
• Patients late in pregnancy

Inspect the perineum of all patients for signs of injury. Traditionally, the digital rectal examination (DRE) was considered an essential part of the physical examination for all trauma patients. However, the sensitivity of the DRE for injuries of the spinal cord, pelvis, and bowel is poor, and false-positive and negative results are common. Thus, routine performance is unnecessary and generally unhelpful.

If the examination is performed, check for Abnormal sphincter tone (sign of spinal cord injury), A high-riding prostate (sign of urethral injury), bone fragments (sign of pelvic fracture), and presence of gross blood (sign of bowel injury).

Perform a vaginal examination on all patients at risk for vaginal injury (e.g., those with lower abdominal pain, pelvic fracture, or perineal laceration). Take care to avoid injury from bone fragments if a pelvic fracture is known or suspected.

Inspect and palpate the entire length of all four extremities assessing for areas of tenderness, decreased rang of motion, deformity, and neurovascular status of each extremity.

Manipulate all joints thought to be uninjured both passively and actively to verify their integrity. Immobilize and obtain x-rays of any area with a suspected fracture.

Note all penetrating wounds, especially those overlying suspected fractures, suggesting an open injury. The treatment of open fractures includes application of a clean dressing, irrigation and debridement, and prophylactic antibiotics. Preliminary low-pressure wound irrigation can be performed in the trauma bay, but definitive irrigation and debridement are performed in the OR.

Post-traumatic compartment syndrome is an important source of patient morbidity. Increasing pain, tense compartments, and pain with passive stretching of the muscles contained within the compartment should prompt immediate measurement of intracompartmental pressures.

Inspect and palpate the pelvis. Ecchymosis over the pelvis or tenderness along with the pelvic ring warrants diagnostic imaging. Examination findings (e.g., instability) or imaging studies consistent with pelvic ring disruption indicate the need for pelvic immobilization and immediate orthopedic evaluation (Image 5). Repeat examinations to assess pelvic stability are unnecessary and likely to exacerbate bleeding

Image 5: Pelvic Fractures

Image Source: Licensed from Shutterstock

The trauma patient's neurologic status can change dramatically over time (e.g., from the effects of an expanding subdural hematoma). Serial examinations should be performed and carefully documented. During the secondary survey, perform a detailed assessment of the sensorimotor function of the extremities and repeat an assessment of the patient's GCS score (see table 4 above).

Examination of the skin may reveal abrasions, ecchymosis, hematoma, lacerations, and seroma formation. Look closely at areas where lesions may be missed, such as the scalp, axillary folds, perineum, and abdominal folds, particularly in obese patients. Do not neglect examination of the back, gluteal fold, and posterior scalp. Penetrating wounds may be present anywhere.

Appropriate tetanus prophylaxis (Baddour & Brown, 2020) should be administered as soon as possible following a wound but should be given even to patients who present late for medical attention (Table 5). This prophylaxis is because the incubation period for tetanus is quite variable. Most cases occur within eight days, but the incubation period can be as short as three days or as long as 21 days.

For patients who have been vaccinated against tetanus previously but are not up to date, there is likely to be little benefit in administering human tetanus immune globulin more than one week or so after the injury. However, for patients thought to be completely unvaccinated, human tetanus immune globulin should be given up to 21 days following the injury. Td or Tdap should be given concurrently to such patients.

Plain x-rays are used during the secondary survey primarily to evaluate the spine, pelvis, and extremities for fractures, dislocations, and foreign bodies.

Multidetector computed tomography (MDCT) has become the modality of choice for imaging trauma patients because of its speed and accuracy. However, most comprehensive whole-body CT scanning ("pan scan") for all patients with significant trauma is methodologically limited and has reached contradictory conclusions. Pending further research, comprehensive CT scanning in patients without significant alterations in mental status is not advocated, and imaging studies should be performed selectively based upon clinical assessment and the mechanism of injury.

While whole-body CT scanning may improve outcomes following certain high-risk trauma, such as explosions, high-speed motor vehicle collisions, and falls from great heights, it should not be used indiscriminately given the short-term risk of contrast-related renal injury and the long-term risk of radiation-induced cancer, as well as, the substantial costs. In an international, multi-center trial, adult trauma patients with evidence of severe injury were randomly assigned to either whole-body CT (n = 541) or selective CT imaging (n = 542). In-hospital mortality did not differ between groups (whole-body CT 86 [16%] versus selective CT 85 [16%]), nor did it differ significantly among patients with polytrauma or brain injury.

Some authors advocate whole-body CT for severely injured patients with alterations in mental status. In a retrospective database analysis of 5,208 patients in Japan with scores on the GCS ranging from 3 to 12, decreased mortality was noted in patients who received whole-body CT scans. Although further study of the outcomes and cost-effectiveness of whole-body CT is needed, the approach may be beneficial in such patients. Examination findings are often limited or unclear.

It should be noted that while CT may be useful in the evaluation of patients with blunt trauma, it has limited utility for evaluating the trajectory and effects of low velocity penetrating injury (e.g., stab wounds) because of the lack of tissue disruption and gas dispersion (seen with high-velocity injuries), and because injuries to luminal structures are often difficult to detect.

Diagnostic laparoscopy may be useful in patients with penetrating injury and signs of peritoneal penetration despite negative CT imaging. Although improving, the accuracy of CT for detecting diaphragm injuries is also limited, and depending on the nature of the patient's injuries, additional diagnostic studies may be needed. Most patients should be hemodynamically stable before CT imaging is performed, and resuscitation should be sufficient to minimize the risk of decompensation while the patient is in the CT scanner. If the patient is unstable, CT imaging is usually deferred.