Podcast #227 - ATLS Episode 5: Abdominal and Pelvic Trauma (Chapter 5)

We are back at it again with our newest ATLS podcast.  This time we are focusing on the abdomen and pelvis which can be host to a wide range of severe pathology.  Given its many intricacies, we focused most on the highlights from ATLS Chapter 5 including the key "red text" that it emphasizes. 

Generally, any injuries from the chin to the umbilicus should be considered concerning for trauma to the thorax.  When it comes to abdominal trauma, consider it when there is trauma between the nipple to the perineum.

PRIMARY ASSESSMENT AND ANATOMY:

• The assessment of circulation during the primary survey includes early evaluation for possible intra-abdominal and/or pelvic hemorrhage in patients who have sustained blunt trauma.
• Unrecognized abdominal and pelvic injuries continue to cause preventable death after truncal trauma.
• Significant blood loss can be present in the abdominal cavity without a dramatic change in the external appearance of dimensions of the abdomen and without obvious signs of peritoneal irritation.
• Injuries to the retroperitoneal visceral structures are difficult to recognize because they occur deep within the abdomen and may not initially present with signs or symptoms of peritonitis.
  • These can also be harder to identify as they are not seen with diagnostic peritoneal lavage (DPL).
  • The extended Focused Assessment with Sonography for Trauma (eFAST) can identify retroperitoneal injuries, but not as easily as other modalities such as computed tomography (CT).
• Significant blood loss can occur from injuries to organs within the pelvis and/or directly from the bony pelvis.

MECHANISMS OF INJURY (MOI):

• Blunt Trauma
  • Airbag deployment does not preclude abdominal injury
    
  • Airbags are often not seated in the correct position especially in obese or pregnant patients.
• Penetrating Trauma
  • Stab wounds and low energy wounds cause tissue damage by lacerating and tearing.
  • High energy gunshot wounds (GSWs) transfer more kinetic energy, causing increased damage surround the track of the missile due to temporary cavitation. 
  • JAMA Article from 2005 demonstrated that the vast majority (97%) of patients had intra-abdominal injury identified at laparotomy, with an additional 45% sustaining injury to an extra-abdominal region.
  • History is a key part to help differentiate the type of projectile, distance from muzzle, and other factors that can impact the severity of the trauma (think Dick Cheney's 2006 hunting accident versus GSWs from a hollow point round at close range).
    
• Blast Trauma
  
  • ​The potential for overpressure injury following an explosion should not distract the clinician from a systematic approach to identifying and treating blunt and penetrating injuries.
    
  • We have discussed blast injuries before in greater detail with Podcast #221.
    

ASSESSMENT AND MANAGEMENT:

• In hypotensive patients, the goal is to rapidly identify an abdominal or pelvic injury and determine whether it is the cause of hypotension.
• Perform frequent abdominal re-evaluation as a single examination does not completely eliminate the presence of injury.
  • Consider performing repeat eFAST exams (especially in a resource limited environment) to identify abnormalities that may not be present initially.
  • Be wary of changes in patients who may be technically within normal ranges but may indeed be in earlier stages of shock (refer to Podcast #215 for further details).
• Hemodynamically normal patients without signs of peritonitis may undergo a more detailed evaluation to determine the presence of injuries that can cause delayed morbidity and mortality.

PHYSICAL EXAMINATION:

• Abdominal examination is conducted in a systematic sequence: inspection, auscultation, percussion, and palpation.
• Examine the pelvis, buttocks, and other areas such as the perineum, urethra, and performing rectal or vaginal exams when indicated.
• This is a great reminder to logroll these patients which can be time and manpower intensive.
• While ATLS does mention auscultation, the presence or absence of bowel sounds does not necessarily correlate with injury and the ability to hear bowel sounds may be compromised in a busy emergency department.
• With percussion, know that when rebound tenderness is present, do not seek additional evidence of irritation as it may cause the patient further unnecessary pain.
• Watch for voluntary versus involuntary guarding.
• A general concept when considering fetal age is that if the fundus is at the umbilicus, this is suggestive of a fetal age of 20 weeks (or more if fundus is above the umbilicus) and can help point toward viability.
• At the conclusion of the rapid physical exam, cover the patient with warmed blankets to help prevent hypothermia.

ADJUNCTS TO PHYSICAL EXAMINATION:

• In patients with hemodynamic abnormalities, rapid exclusion of intra-abdominal hemorrhage is necessary and can be accomplished with either DPL or the eFAST exam.
• A full bladder enhances the pelvic images of the eFAST exam and urinary catheterization should be delayed until this has been completed (if the eFAST is to be performed at all).
• The only potential contraindication to the eFAST exam is if there is an existing indication for laparotomy.
  • Consider still performing the eFAST exam if there are other concerns such as cardiac tamponade or pneumothorax.
  • The eFAST exam is not sensitive for diagnosing hollow viscus injuries and factors like obesity or patient compliance can limit the exam.
  • More can be learned regarding tips to the eFAST exam by visiting Podcast #79 (or take a Practical POCUS course).
• A retrograde urethrogram should be performed if the patient is unable to void, requires a pelvic binder, or has blood at the meatus, scrotal hematoma, or perineal ecchymosis.
  • The absence of hematuria does not exclude an injury to the genitourinary tract.
  • To reduce the risk of increasing the complexing of urethral injury, confirm an intact urethra before urinary catheter placement.
• DPL is rarely used today given the availability of the eFAST exam and CT.
  • Aspiration of gastrointestinal contents, vegetable fibers, or bile through the lavage catheter mandates laparotomy.
  • Additionally, aspiration of 10 cc or more of blood in hemodynamically abnormal patients requires laparotomy.
• CT takes time but is appropriate in hemodynamically normal patients.
  • However, when indications for patient transfer (or laparotomy) already exist, do not perform time-consuming tests such as CT.
  • Avoid CT in those patients that are uncooperative and cannot be safely sedated or those with an allergy to the contrast agent.
  • CTs can still miss some gastrointestinal, diaphragmatic, and pancreatic injuries.
  • In the absence of hepatic or splenic injuries, the presence of free fluid in the abdominal cavity suggests an injury to the gastrointestinal tract and/or its mesentery, and many trauma surgeons believe this finding to be an indication for early operative intervention. 
  • Consider double (IV and oral) or triple (IV, oral, and rectal) contrast studies in certain patient specific situations.
• X-rays are generally not necessary in penetrating abdominal wounds when they are hemodynamically abnormal since this is a patient that is already going to surgery.
  • A chest X-ray should be considered if there is a wound above the umbilicus to evaluate for a possible hemothorax or pneumothorax.
• There are other studies not commonly performed but may be used such as urethrography, cystography, IV pyelogram, and GI contrast studies which is often guided by the surgeon who will be caring for this patient.

EVALUATION OF SPECIFIC INJURIES:

• Pancreatic injuries cannot be excluded when there is a normal amylase level and even if elevated it can be from other sources that are not from the pancreas.
• Contusions, hematomas, and ecchymoses of the back or flank are markers of potential underlying renal injury and warrant an evaluation such as with CT or IV pyelogram of the urinary tract.
  • An anterior urethral injury results from a straddle impact and can be an isolated injury.
  • This was actually discussed some during Podcast #188 when discussing pediatric specific blunt abdominal trauma.
• Although some patients have early abdominal pain and tenderness, the diagnosis of hollow viscus injuries can be difficult since they are not always associated with hemorrhage but look for a seatbelt sign or lumbar Chance fracture.
• Concomitant hollow viscus  injury occurs in less than 5% of patients initially diagnosed with isolated solid organ injuries.
• With pelvic fractures, a sheet or commercial device to bind the pelvis can provide sufficient temporary fixation of the unstable pelvis when applied at the level of the greater trochanters of the femur but avoid over-tightening.
  • Significant resources are required to care for patients with severe pelvic fracture and early transfer to a trauma center is important.
  • Lateral compression injuries are the most common which can result in bladder or urethral injury.
  • Anterior-posterior (AP) compressions are "open book" fractures and can result in severe hemorrhage from tearing of large arteries and veins.
  • Vertical shear fractures at the SI joint or pubic symphysis can often be missed (review your own X-rays as always!).
  • Do not rock the pelvis but consider palpation of the pelvis and then compression of the pelvic spines versus distraction.

Let us know what you think by giving us feedback here in the comments section or contacting us on Twitter or Facebook.  Remember to look us up on Libsyn and on Apple Podcasts.  If you have any questions you can also comment below, email at thetotalem@gmail.com, or send a message from the page.  We hope to talk to everyone again soon.  Until then, continue to provide total care everywhere.

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