Assessment of Abdominal Trauma in the Emergency Department

1. Assessment of Abdominal Trauma in the Emergency Department Debbie Washke, MD Department of Emergency Medicine Loma Linda University Medical Center [Month] [Year]

2. Injury and Abdominal Trauma • Globally, traumatic injury accounts for 10% of all deaths • Trauma is now listed as the leading cause of death in persons between the age of 1-44 • Peak incidence 14-30 years • One in ten deaths in trauma are due to abdominal injuries

3. Mechanism in Blunt Abdominal Trauma ( BAT ) • Compression • Direct blow or compression against a fixed object • Commonly cause tears and subcapsular hematomas to solid viscera • Less commonly, transiently increase intraluminal pressure and lead to rupture • Deceleration • Stretching and linear shearing between a fixed and free object • Hepatic tears along the ligamentum teres, intimal injuries, mesenteric tears

4. Blunt Abdominal Trauma in the ED • Role of the emergency physician • Initial assessment • Mechanism • Difficult to make diagnosis • Resuscitation • Disposition • Indications for the OR • Study Choices • FAST • CT • DPL

5. Initial Assessment • Initially, Evaluation and Resuscitation occur simultaneously • Detailed History may be impossible • AMPLE • Allergies • Medications • Past medical history • Last intake • Events leading to presentation

6. Initial Assessment: Description of mechanism • Predicts injury patterns and helps avoid pitfalls • Type of collision (frontal, lateral, sideswipe, rear, rollover) and speed • Damage to vehicle and whether prolonged extrication was required • Ejection from vehicle and/or co occupant death • Types of restraints • The presence of alcohol or drug use

7. Initial Assessment: History • AMPLE • Mechanism per bystanders, medics etc… • Patients with out of hospital hypotension are at increased risk for significant intra abdominal injury – even if normotensive on arrival to the ED

8. Initial Assessment: Physical Exam • RESCUSITATION continues as PE is completed • Airway, with cervical spine precautions • Breathing • Circulation • Disability • Exposure • Keep entire patient in mind

9. PE: The Secondary Survey • Initial exam of abdomen in blunt trauma is difficult and often unreliable • Powell et al reported that clinical eval alone has an accuracy rate of only 65% for detecting presence or absence of intraperitoneal blood • Most reliable signs and symptoms • Pain, tenderness, GI hemorrhage, evidence of peritoneal irritation • Extremely difficult to assess the abdomen in cases of neurological dysfunction • Head or spinal cord injury • Substance abuse

10. Assessing the Abdomen • Inspection, auscultation, percussion, palpation • Inspection: abrasions, contusions, lacerations, seat-belt signs • Grey Turner, Kehr, Balance and Cullen • Auscultation: careful exam advised by ATLS ( of controversial utility in setting of trauma) • Percussion: Subtle signs of peritonitis; tympany in gastric dilatation or free air, dullness in hemoperitoneum • Palpation: elicit superficial, deep, or rebound tenderness; involuntary guarding

11. Evaluate for pelvic instability Potential for urinary tract injury as well as pelvic or retroperitoneal hematoma Perform rectal exam to identify potential injury or bleed (controversial utility) NG tube for abdominal distention to decompress stomach Foley catheter placement after assessment for GU injury Adjuncts to the Abdominal Exam

12. The Workup: Laboratory Studies • Commonly recommended studies • Serum glucose • CBC • Serum chemistries • Serum amylase • Urinalysis • Coagulation studies • Blood type and match • Blood ethanol, urine drug screens and a urine pregnancy test

13. CBC Normal Hgb and Hct do not rule out significant hemorrhage Delayed drop in acute bleeds Hemodynamic instability much more reliable in assessment of volume status and need for transfusion in setting of trauma Use platelet transfusions to treat severe thrombocytopenia (<50,000/ml) and ongoing hemorrhage WBC count is nonspecific There is increased release of neutrophils from the marrow with physiologic stress

14. Serum Chemistries • Recently the usefulness of routine chemistries has been questioned • Most trauma victims are < 40 y/o, and less likely to take medications that alter electrolytes • Important to recognize that medical conditions due play a role in a small percentage of traumas • Rapid bedside blood-glucose should be obtained in all trauma patients with altered mental status

15. Liver Function Studies • LFT’s may be useful –but elevation may be secondary to other conditions • Alcohol abuse • Hepatic Steatosis • One study shows that ALT or AST > 130 U corresponds with significant hepatic injury • Bilirubin levels: not specific indicators of hepatic injury

16. Amylase measurement • Controversial in setting of blunt abdominal trauma • An initial amylase has been shown to be neither sensitive or specific for pancreatic injury • However…an abnormally elevated level 3-6 hours after initial trauma has greater accuracy

17. Urinalysis • Indications include • significant trauma to the abdomen and/or flank • gross hematuria, significant deceleration mechanism • Gross hematuria indicates a workup that includes cystography and IVP or CT with contrast • Urine pregnancy in females of child bearing age

18. Coagulation profile • Cost effectiveness of routine PT and PTT is questionable • Obtain in patients with a history of • Blood dyscrasias • Synthetic problems • On anticoagulants

19. Blood Type, screen and crossmatch • Screen and type blood from all trauma patients with suspected blunt abdominal injury • Initial crossmatch on a minimum of 4 units • If clear evidence of abdominal injury • And/or hemodynamic instability • Until crossmatch blood available use O-negative or type specific blood • An indication for immediate transfusion is hemodynamic instability despite administration of 2 L of fluid to adult patients

20. Diagnostic Adjuncts • Plain films • FAST ( focused abdominal sonography for trauma) • CT studies • DPL

21. Plain Radiographs • Generally of lower priority, limited value –but can demonstrate important findings • CXR may aid in diagnosis of abdominal injuries such as ruptured hemidiaphragm, pneumoperitoneum, free air • Pelvic or chest x ray may demonstrate fractures of the T and L spines • Transverse fractures of vertebral bodies suggests a higher likelihood of blunt injury to the bowel

22. FAST (focused assessment with sonography for trauma) • Used to evaluate for abdominal injury in blunt trauma since the 1970’s • Bedside ultrasound is rapid, portable, and noninvasive • Interpreted as positive if fluid found in any of the 4 acoustic windows • An exam is indeterminate if any window cannot be adequately assessed

23. FAST • Assumes that all clinically significant abdominal injuries are associated with hemoperitoneum • In reality, detection of free fluid is based on other factors • Body habitus, injury location, presence of clotted blood, position of patient and amount of free fluid present • Minimum threshold for detecting free fluid • Remains a subject of interest • At lower end of spectrum studies have shown that 30-70 ml is minimum requirement for detection by US • In reality, in the hands of most operators it is limited in detecting < 250 ml of intraperitoneal fluid

24. Pericardiac Perihepatic Perisplenic Pelvic The 4 acoustic windows

25. FAST: Accuracy • For identifying hemoperitoneum in blunt abdominal trauma • Sensitivity 76-90% • Specificity 95-100% • Sensitivity increases for clinically significant hemoperitoneum • Rozycki et al; US the most sensitive and specific modality for the evaluation of the hypotensive patient with blunt abdominal trauma

26. Strengths Rapid (~ 2 min ) Portable Relatively inexpensive Technically simple, easy to train ( studies show competence can be achieved after ~ 30 studies Can be performed serially Limiations Does not typically ID source of bleeding, or detect injuries that do not cause hemoperitoneum Limited in detection of intraperitoneal fluid (<250 mL) Poor at detecting bowel and mesenteric damage Difficult to assess retroperitoneum Limited by body habitus in the obese FAST: Strengths and Limitations

27. Diagnostic Peritoneal Lavage • 98% sensitive for intraperitoneal bleeding ( ATLS) • Open or closed (Seldinger); usually infraumbilical • Supraumbilical in pregnancy and pelvic fracture • Free aspiration of blood, GI contents, or bile in hemodynamically unstable patient requires laparotomy

28. Performing DPL • Methods include open, semi open and closed procedures • More typical to perform an open procedure if there are relative contraindications

29. How FAST is it ?? • DPL results are positive if there is free aspiration of blood or GI contents • Samples need to be sent to lab if there is no gross aspiration of above body fluids • Fluid is positive if NS ( drained by gravity) has < 100,000 RBC’s/mL, > 500 WBC’s/mL, elevated amylase content, bile, bacteria, vegetable matter or urine • Delayed decision making process if sample is sent to lab

30. Disadvantages Invasive Difficult to perform in some populations (relative contraindications) Time consuming if no gross blood or GI contents ?? Lavage fluid may interfere with subsequent imaging May lead to high non-therapeutic laparotomy rate ( Bain et al; suggests numbers as high as 36%) Advantages Answers question quickly if there is > 10 mL of blood or GI contents Reported to be more sensitive than either CT or US for detection of hollow viscus injuries ( Hoff et al ) DPL: Advantages vs Disadvantages

31. The Role of DPL • DPL regarded by many authors as obsolete • FAST has replaced DPL as investigation of choice in the hemodynamically unstable patient • It retains a role as a second line investigation tool and an adjunct to FAST • If fluid is found, DPL can help figure out what it is and where it is coming from –but cannot ID the exact source

32. The Abdomen and Pelvic CT • CT scan remains the criterion standard for the detection of solid organ injuries • CT scans unlike FAST examinations or DPL, have capacity to determine the source of hemorrhage • Provide excellent imaging of the pancreas, duodenum, and GU system and can quantitate the amount of blood present in the abdominal cavity

33. Strengths Gold standard for solid organ injury Can determine source of bleeding Detects retroperitoneal injuries that may not be identified by FAST or DPL Reveals associated injuries ( bone and pelvic fractures Limitations Time consuming and typically involve leaving the department In the unstable patient “Death begins with a CT” Marginal sensitivity for diagnosing diaphragmatic injuries, pancreatic and hollow viscus injuries Relatively expensive Require IV contrast, which may cause an adverse reaction CT: Strengths and Limitations

34. Does FAST replace CT? Only at the extremes • Unstable patient, (+) FAST  OR • Stable patient, low force injury, (-) FAST  consider observing patient and doing serial FAST exams

35. EAST Algorithm: Unstable

36. EAST Algorithm: Stable

37. CT: EAST trauma guidelines EAST level I recommendations (2001): • CT is recommended for evaluation of hemodynamically stable patients with equivocal findings on physical exam, associated neurological injury, or multiple extra-abdominal injuries • CT is the diagnostic modality of choice for nonoperative mgmt of solid visceral injuries

38. Solid Organ Injuries • Spleen • Liver • Pancreas

39. Spleen Injury • Most commonly injured organ • 25% of blunt abdominal injuries • Signs and symptoms often subtle • Left lower rib fractures • Non operative management in hemodynamically stable patients • Immunologic function has promoted salvage of the spleen rather than splenectomy

40. Spleen Injury • Non-operative management attempted in 60-80% • 85-94% successful • 2/3 will fail nonoperative mgmt within the first 24 hours • Salvage rates decrease with injury severity • Injury grade is not predictive of who will fail • Approx 10% will worsen as outpatient

41. Hepatic Injury • Relatively fixed position • Suspect in right lower chest injuries, rib fractures 7-10 • 2nd most common organ injured • 15-20% of blunt abdominal injuries • Driving and fighting ( not necessarily at the same time ) • Responsible for 50% of deaths • Non-operative management in hemodynamically stable patients

42. Hepatic Injury • Grade of Injury does not necessarily predict non operative failures • Failure rates approximately 2% • If stable with ongoing bleeding –angiographic embolization

43. Pancreas Injury • Isolated injury to this organ is uncommon • More frequently associated with liver injury • Missed injuries do occur • Normal in up to 40% of patients • Mechanism most often crush and transection • Delayed serum amylase elevations are much more sensitive • Significant injury carries grave prognosis

44. Bowel and Mesenteric Injury • Occurs in 5% of abdominal trauma • Mechanisms of injury • Compression – increasing the intraluminal pressure in the bowel or by compressing fluid-filled bowel against solid structures • Deceleration –stretching and tearing of bowel loops at points of fixation • Difficult to diagnose • Seatbelt sign present in 21%

45. Bowel Injuries • Most Common Sites of Injury • Jejunum, ileum > colon, duodenum ( 2nd and 3rd portions ) • Requires emergent operative management • Undiagnosed injuries lead to fatal peritonitis or hemorrhage • Atypical for peritonitis to be present early on

46. CT findings: Bowel and Mesentery • Signs of injury on CT • Bowel – Direct • Bowel wall disruption • Oral contrast extravasation (typically forego this in trauma scenarios) • Bowel – Indirect • Free air • Focal bowel wall thickening, wall enhancement • Mesentery – Direct • IV contrast extravasation • Mesentery – Indirect • Diffuse bowel wall thickening, enhancement • Mesenteric hematoma

47. CT in Bowel and Mesentery Injury • CT is currently best imaging tool • DPL is more sensitive (for bowel injury) but invasive – minimal role in mesentery injury • CT sensitivity • 94% for bowel injury • 96% for mesentery injury

48. Diaphragmatic Injury • Diaphragm rupture rarely occurs as an isolated injury • Pelvic fracture • Splenic rupture • Liver laceration • Thoracic aorta injury • Only 40-50% are diagnosed immediately

49. Diaphragm Rupture • Uncommon – fewer than 5% • 80-90% occur due to MVC • Mechanism • Left lateral impact – 3x more likely than frontal impact • 80-90% occur on the left

50. Penetrating Trauma: Historic Timeline • Before WWI managed expectantly • During WWII studies showed early laparotomy improved survival • By late 1950’s laparotomy became standard • In 1960’s Shaftan suggested selective mgmt of stab wounds after observing an increased rate of ex laps with no identifiable injuries