Abdominal Trauma

Answer: Quick Answer: Abdominal trauma evaluation requires systematic assessment combining clinical examination, imaging (FAST and CT), and laboratory investigations. Blunt injuries are managed non-operatively in hemodynamically stable patients with solid organ injuries grades I-III. Penetrating injuries typically require operative intervention. FAST has 70-85% sensitivity for hemoperitoneum in unstable patients but is operator-dependent. DPL is largely replaced by FAST. AAST organ injury scales guide management decisions.

CICM Second Part Exam Focus

High-Yield Topics

• FAST examination technique and interpretation
• AAST organ injury scales (liver, spleen, kidney)
• Indications for laparotomy vs non-operative management
• Hollow viscus injury recognition
• Diagnostic peritoneal lavage technique and interpretation

Common SAQ Themes

• Evaluation algorithm for blunt abdominal trauma
• Management of hemodynamically unstable abdominal trauma
• Non-operative management criteria for solid organ injury
• Comparison of FAST vs DPL vs CT abdomen

Viva Emphasis

• FAST probe placement and image interpretation
• Clinical decision-making in penetrating vs blunt trauma
• Recognition of hollow viscus injury
• Complications of abdominal trauma and their management

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Epidemiology and Mechanisms

Trauma Patterns

Abdominal trauma accounts for approximately 10-15% of all trauma admissions and is a significant contributor to trauma-related mortality. [1] The mechanisms of injury fundamentally differ between blunt and penetrating trauma, with distinct patterns of organ involvement and diagnostic considerations.

Blunt Abdominal Trauma

Blunt mechanisms predominate in civilian trauma, accounting for 75-85% of abdominal injuries in most series. [2] Common mechanisms include:

• Motor vehicle collisions: Seatbelt and steering wheel injuries
• Pedestrian vs vehicle: Compression and deceleration injuries
• Falls from height: Hepatic and splenic injuries
• Assaults: Direct blows to abdomen

The pathophysiology involves energy transmission through solid organs, vascular structures, and the mesentery. Deceleration forces cause shearing injuries at points of fixation, including the duodenum at the ligament of Treitz and the small bowel at the ileocaecal valve. [3]

Liver is the most commonly injured solid organ in blunt trauma (30-40% of cases), followed by spleen (25-35%) and kidney (10-20%). [2] Hollow viscus injuries occur in 1-5% of blunt trauma and are often associated with seatbelt sign, rapid deceleration, or direct blows.

Penetrating Abdominal Trauma

Penetrating injuries account for 15-25% of abdominal trauma and result from:

• Stab wounds: Low-velocity, limited track predicable
• Gunshot wounds: High-velocity, cavitation, unpredictable track
• Impalement injuries: Retained foreign body

Stab wounds penetrate the peritoneal cavity in 50-70% of cases, with actual organ injury in only 20-30%. [4] Gunshot wounds have peritoneal penetration rates exceeding 90% and organ injury in 70-80%. [5]

Hollow viscus injuries are more common in penetrating trauma (20-30%) compared to blunt trauma. Small bowel injuries predominate (50-60%), followed by colon (20-30%) and stomach (10-15%). [6]

Injury Patterns by Mechanism

⚠️ Red Flag: Seatbelt sign across abdomen in blunt trauma significantly increases risk of hollow viscus injury (up to 20-30%) and mandates high index of suspicion for small bowel or mesenteric injury.

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Initial Assessment and Primary Survey

ABCDE Approach

Abdominal trauma evaluation follows ATLS principles with simultaneous assessment and resuscitation. The abdomen is evaluated during the C (circulation) and D (disability) phases.

Key priorities in the primary survey:

1. Airway with cervical spine protection
2. Breathing: Assess for diaphragmatic injury (elevated hemidiaphragm, absent breath sounds)
3. Circulation: Identify external haemorrhage, assess for abdominal distension, establish large-bore IV access
4. Disability: Assess level of consciousness (GCS), which may be depressed from hypovolaemia
5. Exposure/Environmental control: Log-roll to examine back and flank

Secondary Survey: Abdominal Examination

Inspection

• Contusions, lacerations, seatbelt sign
• Abdominal distension (suggestive of haemoperitoneum)
• Evisceration (penetrating injuries)
• Wounds in lower thorax or upper back (potential abdominal penetration)

Auscultation

• Bowel sounds (often absent in significant abdominal injury)
• Bruits (vascular injury)

Percussion

• Dullness to percussion (suggestive of fluid/blood)
• Tympany (suggestive of hollow viscus injury with pneumoperitoneum)

Palpation

• Generalised or localised tenderness
• Guarding and rigidity (peritonitis)
• Pulsatile mass (retroperitoneal haematoma)
• Pelvic instability (associated pelvic fracture)

⚠️ Red Flag: Abdominal examination has poor sensitivity for significant intra-abdominal injury in blunt trauma (30-60%), particularly in patients with altered sensorium, spinal cord injury, or distracting injuries.

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Diagnostic Evaluation

Focused Assessment with Sonography for Trauma (FAST)

Technique and Views

FAST examination is a rapid bedside ultrasound protocol performed as part of the primary survey in hemodynamically unstable trauma patients. The standard four-view protocol includes:

1. Right Upper Quadrant (RUQ) View: Morison's pouch (hepatorenal recess)
2. Left Upper Quadrant (LUQ) View: Splenorenal recess and left subdiaphragmatic space
3. Pericardial View: Subxiphoid four-chamber view
4. Pelvic View: Rectovesical pouch in males or rectouterine pouch (pouch of Douglas) in females

Probe selection: Low-frequency curvilinear probe (3.5-5 MHz) for optimal depth penetration.

RUQ View Technique

• Patient supine, probe placed in right mid-axillary line at 8th-9th intercostal space
• Identify kidney and liver interface
• Morison's pouch is the most dependent space in the supine patient
• Scan cephalad to left hepatic lobe and subphrenic space
• Scan caudad to right paracolic gutter

LUQ View Technique

• Probe placed in left posterior axillary line at 8th-9th intercostal space
• Identify spleen and left kidney
• Splenorenal recess is examined
• Scan cephalad to left subdiaphragmatic space
• Scan caudad to left paracolic gutter

Pelvic View Technique

• Probe placed transversely in suprapubic region
• Direct beam into pelvis in both transverse and sagittal planes
• Visualise bladder as acoustic window
• Examine rectovesical pouch (males) or pouch of Douglas (females)

FAST Findings and Interpretation

Positive FAST: Presence of anechoic (black) fluid in dependent abdominal compartments. Free fluid appears black compared to solid organs which are grey with echogenic texture.

Answer: FAST Interpretation Criteria:

• Positive: Any anechoic fluid in Morison's pouch, splenorenal recess, or pelvis
• Negative: No free fluid identified
• Indeterminate: Poor acoustic windows or equivocal findings

Diagnostic Performance The accuracy of FAST varies significantly by hemodynamic status and operator experience:

FAST is most sensitive in unstable patients with active haemorrhage (sensitivity 80-90%) and less sensitive in stable patients or those with retroperitoneal injuries. [7] False negatives occur with retroperitoneal haemorrhage, solid organ injuries without capsular rupture, and small volume haemoperitoneum (below 150-200 mL). [8]

The minimum detectable volume of free fluid by FAST is approximately 150-200 mL, though experienced operators may detect smaller volumes. [8] Sensitivity increases to greater than 90% when hemoperitoneum exceeds 500 mL. [7]

FAST in Penetrating Trauma

FAST has lower sensitivity in penetrating abdominal trauma (50-65%) due to variable fluid distribution, retroperitoneal injuries, and early presentation with limited time for haemoperitoneum accumulation. [9]

Indications for FAST in penetrating trauma:

• Hemodynamic instability
• Unclear trajectory of wound
• Associated thoracic injury

A positive FAST in penetrating trauma is an indication for laparotomy. However, a negative FAST does not exclude intra-abdominal injury, and further evaluation (local wound exploration, CT, or diagnostic laparoscopy) is often required. [9]

FAST Training and Competency

FAST requires supervised training with 25-50 documented examinations for basic competency and 100-200 examinations for proficiency. [10] Skill decays without regular practice, and quality assurance programs with image review are recommended.

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Diagnostic Peritoneal Lavage (DPL)

Technique

DPL is a percutaneous catheter-based assessment of peritoneal contents, historically used when FAST was unavailable or indeterminate. The technique involves:

1. Patient preparation: Supine position, bladder decompression, anaesthetic to skin and fascia
2. Access: Open technique with infraumbilical incision (midline periumbilical), peritoneal entry under direct vision
3. Catheter insertion: Peritoneal dialysis catheter (18-20 Fr) advanced into pelvis
4. Aspiration: Immediate aspiration of 10 mL
5. Lavage: If initial aspiration negative, instill 1 L warm saline
6. Drainage: Allow fluid to drain by gravity, collect sample for analysis

Contraindications include previous abdominal surgery (risk of adhesions), advanced pregnancy, and known pelvic fracture (risk of bladder injury requiring supraumbilical approach). [11]

DPL Interpretation

Answer: DPL Criteria for Positive Lavage:

• Gross blood: Immediate aspiration of greater than 10 mL gross blood (positive laparotomy)
• RBC count: greater than 100,000 RBC/mm³ in lavage effluent
• WBC count: greater than 500 WBC/mm³ (suggestive of hollow viscus injury)
• Bile, bacteria, or vegetable matter: Any amount (mandates laparotomy)

Diagnostic performance:

• Sensitivity: 95-98%
• Specificity: 90-95%
• Accuracy: 92-96%

DPL is more sensitive than FAST for detecting small amounts of free fluid (below 100 mL) and is particularly useful for identifying hollow viscus injury (WBC count elevation, bile presence). [11]

Limitations and complications:

• Invasive with potential complications (2-5%): wound infection, haemorrhage, catheter misplacement, bowel perforation
• Operator-dependent
• Does not localise injury
• False positives from pelvic fractures or minor solid organ injuries
• Does not assess retroperitoneum

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Computed Tomography (CT) Abdomen

Indications

CT abdomen with intravenous contrast is the gold standard imaging modality for hemodynamically stable trauma patients with suspected intra-abdominal injury. [12]

Absolute indications for CT:

• Hemodynamically stable patients with abdominal pain or tenderness
• Decreased haemoglobin or mechanism suggestive of abdominal injury
• Unclear FAST examination
• Pelvic or spinal fractures (associated visceral injury)
• High-energy mechanism without definitive abdominal findings

Relative contraindications:

• Hemodynamic instability
• Contrast allergy (consider premedication)
• Renal insufficiency (risk of contrast nephropathy)
• Pregnancy (consider MRI or limited CT)

CT Protocol

Modern multidetector CT (64-slice or greater) enables rapid acquisition with thin slices (0.6-1.25 mm) and multiplanar reconstruction.

Standard trauma CT protocol:

• Arterial phase (30-40 seconds): Active haemorrhage, vascular injury
• Portal venous phase (70-80 seconds): Solid organ injuries, parenchymal enhancement
• Delayed phase (3-5 minutes): Urinary tract injury (renal collecting system)

Oral contrast: Most centres now omit oral contrast in acute trauma as it delays imaging and adds little value. Intravenous contrast is mandatory. [13]

Window and level adjustments:

• Soft tissue windows: W 400, L 40 (solid organs, parenchyma)
• Lung windows: W 1500, L -600 (pneumoperitoneum)
• Bone windows: W 2000, L 500 (fractures)

CT Findings in Abdominal Trauma

Solid organ injuries:

• Liver: Parenchymal laceration, subcapsular haematoma, active extravasation
• Spleen: Laceration, intraparenchymal haematoma, vascular pedicle injury
• Kidney: Laceration, perinephric haematoma, contrast extravasation, absent excretion

Hollow viscus injuries:

• Pneumoperitoneum: Free air on lung windows
• Bowel wall thickening: greater than 3 mm
• Mesenteric stranding: Fat stranding, haematoma
• Free fluid without solid organ injury: Suggestive of hollow viscus injury

Vascular injuries:

• Active extravasation: Hyperdense blush on arterial phase
• Pseudoaneurysm: Contrast-filled outpouching
• Arteriovenous fistula: Early venous opacification
• Venous injury: Perivascular haematoma, lack of opacification

⚠️ Red Flag: Active contrast extravasation on CT indicates ongoing haemorrhage and mandates urgent intervention (angiographic embolisation or laparotomy). The "sentinel clot sign" (highest attenuation clot adjacent to injury) identifies the source of haemorrhage.

CT Accuracy

CT abdomen has excellent diagnostic accuracy for intra-abdominal injury in stable patients:

• Sensitivity: 92-97%
• Specificity: 94-98%
• Overall accuracy: 95-97%

CT is superior to FAST for detecting retroperitoneal injuries, hollow viscus injuries (especially with pneumoperitoneum), and solid organ injuries without haemoperitoneum. [12]

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Solid Organ Injuries

AAST Organ Injury Scales

The American Association for the Surgery of Trauma (AAST) organ injury scales provide standardised grading systems for solid organ injuries. These grades correlate with mortality, need for operation, and guide management decisions. [14]

Liver Injury Scale

Grade I: Hematoma subcapsular, below 10% surface area; Laceration capsular, below 1 cm depth

Grade II: Hematoma subcapsular, 10-50% surface area; Intraparenchymal below 10 cm; Laceration capsular, 1-3 cm depth, below 10 cm length

Grade III: Hematoma subcapsular greater than 50% surface area or expanding; Ruptured subcapsular or intraparenchymal hematoma; Laceration greater than 3 cm depth

Grade IV: Parenchymal destruction involving 25-75% of hepatic lobe or greater than 3 Couinaud segments in one lobe

Grade V: Parenchymal destruction greater than 75% of hepatic lobe; Juxtahepatic venous injuries (retrohepatic IVC, major hepatic veins)

Grade VI: Hepatic avulsion

Spleen Injury Scale

Grade I: Hematoma subcapsular below 10% surface area; Laceration capsular below 1 cm depth

Grade II: Hematoma subcapsular 10-50% surface area; Intraparenchymal below 5 cm; Laceration capsular 1-3 cm depth, below 10 cm length

Grade III: Hematoma subcapsular greater than 50% surface area or expanding; Ruptured subcapsular or intraparenchymal hematoma; Laceration greater than 3 cm depth or involving trabecular vessels

Grade IV: Laceration involving segmental or hilar vessels with devascularisation (greater than 25% spleen)

Grade V: Shattered spleen or hilar vascular injury

Kidney Injury Scale

Grade I: Contusion or hematoma; Microscopic or gross hematuria; Urography normal

Grade II: Hematoma nonexpanding confined to renal parenchyma; Laceration below 1 cm depth without urinary extravasation

Grade III: Renal parenchymal laceration greater than 1 cm depth without urinary extravasation

Grade IV: Renal parenchymal laceration extending through cortex, medulla, collecting system; Vascular injury (main renal artery or vein) with contained hematoma

Grade V: Renal pedicle avulsion or shattered kidney

Management by AAST Grade

Non-operative management (NOM) criteria:

• Hemodynamic stability (SBP greater than 90 mmHg, HR below 110 bpm, lactate below 2.5 mmol/L)
• Grade I-III injuries (selected grade IV)
• No peritonitis
• No contrast extravasation on CT
• No significant associated injuries
• ICU or high-dependency monitoring capability

Answer: Non-operative Management Success Rates by Grade:

• Grade I-II: greater than 95% success
• Grade III: 80-90% success
• Grade IV: 50-70% success (highly selected patients)
• Grade V: below 10% success (operative management required)

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Liver Injury Management

Non-operative Management

NOM is the standard of care for 80-90% of liver injuries, including 70-80% of grade III-IV injuries in haemodynamically stable patients. [15] The non-operative management rate for liver injuries exceeds 90% in contemporary trauma series.

Key elements of NOM:

• Strict haemodynamic monitoring (hourly vitals, lactate q6h)
• Serial abdominal examinations (every 4-6 hours)
• Serial haemoglobin monitoring (q6-12h)
• Bed in strict bed rest for 24-48 hours
• Blood type and crossmatch available
• Activity restriction for 4-6 weeks post-discharge
• CT follow-up at 7-10 days for high-grade injuries

Adjunctive interventions:

• Angiographic embolisation: Indicated for active contrast extravasation on CT, pseudoaneurysm, or arteriovenous fistula. Embolisation success rates exceed 90% and can convert unstable patients to operative candidates. [16]
• Blood transfusion: Maintain haemoglobin greater than 70-80 g/L
• Correction of coagulopathy: FFP, platelets, tranexamic acid

Failure of NOM (occurs in 5-15%):

• Hemodynamic instability despite resuscitation
• Expanding or ruptured haematoma
• Peritonitis or increasing abdominal pain
• Rising lactate or transfusion requirement (greater than 4 units in 24h)
• Bile peritonitis (from major bile duct injury)

Operative Management

Indications for laparotomy include hemodynamic instability, peritonitis, and failure of NOM. Operative strategies include:

Damage control principles:

• Rapid control of haemorrhage with manual compression, Pringle manoeuvre (portal triad clamping)
• Definitive repair deferred until normal physiology restored
• Temporary abdominal closure (vacuum dressings) with planned reoperation

Specific techniques:

• Simple ligation: For peripheral non-hilar injuries
• Topical haemostatic agents: Fibrin sealants, collagen patches
• Mesh hepatorrhaphy: For extensive parenchymal injuries
• Resectional debridement: For devitalised tissue (formal hepatic lobectomy rarely required)
• Vascular shunting: For juxtahepatic venous injuries (complex, high mortality)

Bile duct injuries: Rare (below 5% of liver injuries), managed with drainage (T-tube or external drain) or reconstruction. Endoscopic stenting may be used for distal common bile duct injuries.

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Spleen Injury Management

Non-operative Management

NOM is the preferred management for 90-95% of spleen injuries in adults and exceeds 95% in paediatric patients. [17] Splenic preservation avoids OPSI (overwhelming post-splenectomy infection) with lifelong mortality risk of 1-2% and 50-fold increased risk of fulminant sepsis from encapsulated organisms.

NOM success rates:

• Grade I-II: 98-100% success
• Grade III: 90-95% success
• Grade IV: 70-85% success (selected patients)
• Grade V: below 20% success (operative management required)

Pseudocyst formation occurs in 2-5% and is managed with observation or percutaneous drainage.

Adjunctive interventions:

• Angiographic embolisation: Indicated for active extravasation, pseudoaneurysm, or arteriovenous fistula. Proximal splenic artery embolisation preserves spleen but may cause infarction; selective distal embolisation preserves more parenchyma. Embolisation reduces failure of NOM from 15% to below 5%. [18]

Operative Management

Indications include hemodynamic instability, peritonitis, and failure of NOM.

Operative techniques:

• Splenic repair: Parenchymal suturing, topical haemostatic agents, mesh splenorrhaphy
• Partial splenectomy: For polar injuries with preserved hilar blood supply
• Total splenectomy: For shattered spleen, hilar vascular injury, or failed splenic salvage

Post-splenectomy management:

• Vaccinations: Pneumococcal, meningococcal, Haemophilus influenzae type b (administered 2 weeks post-op if possible, otherwise pre-discharge with booster doses)
• Antibiotic prophylaxis: Lifelong penicillin prophylaxis recommended for children and high-risk adults (consider penicillin V 500 mg BID or amoxicillin 500 mg daily)
• Patient education: Urgent medical attention for febrile illness; medical alert bracelet

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Kidney Injury Management

Non-operative Management

NOM is standard for 85-95% of renal injuries, including selected grade IV injuries. [19] Urine output monitoring is essential (target greater than 0.5 mL/kg/hr). Hematuria is not a reliable marker of renal injury severity.

Ureteral catheterisation: Indicated for grade IV-V injuries with urinary extravasation to decompress collecting system and reduce urinoma formation.

Operative Management

Indications include hemodynamic instability from renal bleeding, expanding retroperitoneal haematoma, and renal pedicle avulsion.

Operative techniques:

• Renorrhaphy: Parenchymal suturing with absorbable sutures over bolster
• Partial nephrectomy: For polar injuries with devitalised tissue
• Total nephrectomy: For shattered kidney, renal pedicle avulsion, or failed renal salvage

Nephrectomy rate: 5-15% for high-grade renal injuries. Nephron-sparing procedures are preferred when possible, particularly in solitary kidney or pre-existing renal insufficiency.

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Hollow Viscus Injuries

Small Bowel Injuries

Mechanisms and Presentation

Small bowel injuries occur in 1-5% of blunt trauma and 15-25% of penetrating trauma. [20] Blunt mechanisms include:

• Deceleration injury: Shearing at fixed points (duodenum at ligament of Treitz, ileum at ileocaecal valve)
• Seatbelt injury: Direct compression between lap belt and spine
• Handlebar injury: Direct blow in bicycle accidents
• Bursting: Sudden increase in intraluminal pressure (blunt trauma to full abdomen)

Clinical features develop over hours and include:

• Abdominal pain (may be initially mild)
• Peritonitis (develops as perforation evolves)
• Seatbelt sign across abdomen (high-risk marker)
• Elevated WBC count (greater than 12,000)
• Unexplained fever or tachycardia

⚠️ Red Flag: Hollow viscus injury may have minimal initial signs. Delay in diagnosis increases mortality from below 5% to greater than 30%. Any patient with significant abdominal trauma mechanism and unexplained leukocytosis, persistent pain, or fever requires high index of suspicion.

Diagnosis

CT findings in small bowel injury include:

• Pneumoperitoneum (free air, most specific sign)
• Bowel wall thickening (greater than 3 mm)
• Mesenteric fat stranding
• Free fluid without solid organ injury
• Mesenteric haematoma
• Contrast extravasation (rare)

CT sensitivity for small bowel injury is 60-80% with specificity 85-95%. False negatives occur with perforations without pneumoperitoneum or early presentation. [20]

Diagnostic laparoscopy is indicated for equivocal CT findings or high clinical suspicion. Diagnostic laparoscopy can diagnose small bowel injury with greater than 90% accuracy and avoid non-therapeutic laparotomy. [21]

Management

Operative management is required for all confirmed small bowel injuries.

Operative techniques:

• Primary repair: Simple transverse closure for limited injuries (below 50% circumference)
• Resection and anastomosis: For extensive injuries, multiple injuries, or devascularised segments
• Damage control: Exteriorisation or stapled closure with planned reoperation

Duodenal injuries (10-15% of small bowel injuries) have higher morbidity due to proximity to pancreas and biliary tree. Management includes:

• Grade I-II: Simple repair with omental patch
• Grade III: Repair with pyloric exclusion or gastrojejunostomy
• Grade IV: Pancreaticoduodenectomy (rarely required, high mortality)

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Colon Injuries

Mechanisms and Presentation

Colon injuries occur in below 1% of blunt trauma and 5-10% of penetrating trauma. Blunt mechanisms include:

• Direct blows (handlebar, seatbelt)
• Deceleration injuries at points of fixation (sigmoid, hepatic flexure)
• Associated pelvic fractures with rectal injury

Rectal injuries are particularly challenging, occurring in 1-3% of pelvic fractures and carrying high infection risk.

Diagnosis

CT findings include pneumoperitoneum, bowel wall thickening, mesenteric haematoma, and free fluid.

Digital rectal examination is mandatory for pelvic trauma and lower abdominal wounds to assess for blood, rectal tone, and sphincter injury.

Management

Primary repair is preferred for most colon injuries (70-80% of cases) with low leak rates (below 5%) when patient is haemodynamically stable, peritoneal contamination is limited, and repair without tension is possible. [22]

Diverting colostomy is indicated for:

• Extensive colonic destruction
• Shock requiring massive transfusion (greater than 10 units)
• Delayed diagnosis (greater than 24 hours) with peritonitis
• High-velocity rectal injuries
• Contaminated field with extensive tissue loss

Intracolonic bypass (tube colostomy) is an alternative for selected injuries.

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Hollow Viscus Injury Outcomes

Mortality for hollow viscus injury is 10-15% overall, increasing to greater than 30% with delayed diagnosis or associated injuries. Sepsis and anastomotic leak are major complications. Intra-abdominal abscess formation occurs in 10-15% and requires percutaneous drainage or reoperation.

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Vascular Injuries

Abdominal Vascular Anatomy and Injury Patterns

Abdominal vascular injuries are rare (1-5% of abdominal trauma) but carry high mortality (30-50% overall, greater than 80% for juxtahepatic venous injuries). [23]

Vascular injury patterns:

• Major arteries: Aorta, coeliac axis, superior mesenteric artery, renal arteries, iliac arteries
• Major veins: Inferior vena cava, portal vein, renal veins, iliac veins
• Solid organ parenchymal vasculature: Lobar and segmental vessels

Inferior Vena Cava Injuries

Location-based mortality:

• Infrarenal IVC: Mortality 30-40% (repairable)
• Juxtarenal IVC: Mortality 40-50%
• Suprarenal IVC: Mortality 50-60%
• Retrohepatic IVC: Mortality 60-80%

Management: Infrarenal IVC injuries may be repaired with lateral venorrhaphy or shunting. Retrohepatic IVC injuries often require liver mobilisation, vascular control with atriocaval shunt, or balloon tamponade. [24]

Superior Mesenteric Artery Injuries

SMA injuries carry high mortality (40-60%) due to associated bowel ischemia. [25]

Management:

• Proximal injuries: Repair or bypass (saphenous vein or prosthetic graft)
• Distal injuries: Revascularisation or resection of ischemic bowel segment
• Revascularisation priority: below 6 hours warm ischemia time

Outcomes: Survival 50-60%; bowel viability preserved in 70-80% with timely revascularisation.

Aortic Injuries

Abdominal aortic injuries are rare (below 1% of abdominal trauma) with high mortality (50-70%). [26]

Management:

• Suprarenal aorta: Repair with primary closure or interposition graft
• Infrarenal aorta: Repair or bypass, consider endovascular stent graft in selected patients
• Shunting: Aortic cross-clamping for control; avoid prolonged cross-clamp time (greater than 30 minutes associated with increased mortality)

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Management Algorithms

Blunt Abdominal Trauma Algorithm

Blunt Trauma
    │
    ├─► Hemodynamically UNSTABLE
    │       ├─► FAST Positive → Immediate Laparotomy
    │       ├─► FAST Negative → Re-evaluate (DPL vs serial FAST vs empiric laparotomy)
    │       └─► FAST Indeterminate → DPL or proceed to laparotomy
    │
    └─► Hemodynamically STABLE
            ├─► Abdominal tenderness or high-risk mechanism → CT Abdomen
            ├─► CT Positive for solid organ injury → Consider NOM vs Operative
            ├─► CT Positive for hollow viscus injury → Laparotomy
            ├─► CT Negative → Observation, serial exams
            └─► CT Indeterminate → Admission for observation, repeat CT if clinical deterioration

Penetrating Abdominal Trauma Algorithm

Penetrating Trauma
    │
    ├─► Hemodynamically UNSTABLE
    │       └─► Immediate Laparotomy (regardless of FAST)
    │
    ├─► Hemodynamically STABLE with Peritonitis
    │       └─► Laparotomy
    │
    ├─► Hemodynamically STABLE WITHOUT Peritonitis
    │       ├─► Anterior Abdominal Wall Stab (AWST) → Local Wound Exploration
    │       │       ├─► Peritoneal penetration → Laparotomy vs Diagnostic Laparoscopy
    │       │       └─► No penetration → Discharge after observation
    │       │
    │       ├─► Thoracoabdominal Stab Wound → CT or Diagnostic Laparoscopy
    │       │       └─► Diaphragm injury → Laparotomy ± Thoracotomy
    │       │
    │       ├─► Back/Flank Stab Wound → Triple-contrast CT
    │       │       ├─► Retroperitoneal injury → Management based on organ injured
    │       │       └─► No injury → Discharge after observation
    │       │
    │       └─► Gunshot Wound → Laparotomy (mandatory in most protocols)
    │               └─► Selected anterior GSW without peritonitis → CT possible
    │                       ├─► Track through solid organ only → Consider NOM
    │                       └─► Track through hollow viscus → Laparotomy
    │
    └─► Serial Examination → Observation unit (6-12 hours minimum)
            └─► Deterioration → Laparotomy

Answer: Key Decision Points in Abdominal Trauma:

• Unstable + FAST positive: OR immediately
• Unstable + FAST negative: Re-evaluate, consider DPL or empiric laparotomy
• Stable + peritonitis: Laparotomy (penetrating) or CT (blunt)
• Stable + CT positive solid organ: NOM if grades I-III and stable
• Stable + CT positive hollow viscus: Laparotomy
• Stable + CT negative: Observation with serial exams

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Indications for Laparotomy

Mandatory Laparotomy (Absolute Indications)

Hemodynamic instability:

• SBP below 90 mmHg refractory to resuscitation (greater than 2 L crystalloid, 2 units blood)
• Persistent tachycardia (greater than 120 bpm) with abdominal distension
• Rising lactate greater than 4 mmol/L or persistent acidosis

Peritonitis:

• Generalised peritonitis
• Localised peritonitis (rigidity, guarding, rebound)
• Evisceration

Imaging findings:

• Active contrast extravasation on CT
• Pneumoperitoneum (hollow viscus perforation)
• Major vascular injury

Gross blood on DPL (immediate aspiration of greater than 10 mL) or RBC greater than 100,000/mm³

High-grade solid organ injury with haemodynamic instability or peritonitis

Relative Indications

Blunt trauma with equivocal findings:

• Unexplained metabolic acidosis
• Unexplained leukocytosis (greater than 15,000)
• Persistent abdominal pain beyond 24 hours

Penetrating trauma:

• Gunshot wound traversing peritoneal cavity
• Stab wound with peritoneal penetration and equivocal local wound exploration
• Thoracoabdominal wounds (diaphragmatic injury risk)

Non-therapeutic Laparotomy Rate

The non-therapeutic laparotomy rate is 5-15% for blunt trauma and 10-20% for penetrating trauma. [27] Diagnostic laparoscopy can reduce non-therapeutic laparotomy in penetrating trauma to below 5%.

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Non-operative Management (NOM)

Principles and Eligibility

NOM is the preferred management for selected solid organ injuries, reducing morbidity, preserving organ function, and decreasing resource utilisation.

Eligibility criteria:

Answer: Non-operative Management Inclusion Criteria:

1. Haemodynamic stability (SBP greater than 90 mmHg, HR below 110 bpm, lactate below 2.5 mmol/L)
2. No peritonitis (soft, non-tender abdomen or focal tenderness without rigidity)
3. Grade I-III solid organ injury (selected grade IV)
4. No active contrast extravasation on CT
5. No significant associated injuries requiring laparotomy
6. Ability for ICU or high-dependency monitoring
7. Blood products and surgical capabilities available

NOM Protocol

Initial 24-48 hours:

• ICU admission (grade III-IV) or high-dependency unit (grade I-II)
• Strict bed rest, nil by mouth initially
• Hourly vital signs (BP, HR, RR, SpO2, temperature)
• Lactate q6h
• Haemoglobin q6-12h (maintain greater than 70-80 g/L)
• Strict input/output monitoring (urine output greater than 0.5 mL/kg/hr)
• Abdominal examination q4-6h

Adjunctive interventions:

• Angiographic embolisation for active extravasation or pseudoaneurysm
• Transfusion to maintain haemoglobin greater than 70-80 g/L
• Correction of coagulopathy (INR below 1.5, platelets greater than 50)

Discharge criteria:

• Haemodynamically stable for 48 hours
• No abdominal pain or minimal tenderness
• Normalising or stable haemoglobin
• Oral diet tolerated
• Mobilising independently
• CT follow-up at 7-10 days (for high-grade injuries)

Failure of NOM

Failure occurs in 5-15% and typically manifests within 24-48 hours of admission. [28]

Signs of failure:

• Hypotension (SBP below 90 mmHg) despite resuscitation
• Increasing abdominal pain or peritonitis
• Rising lactate (greater than 2 mmol/L increase)
• Transfusion requirement greater than 4 units in 24 hours
• Expanding or ruptured haematoma on repeat imaging
• Bile peritonitis (bile in drainage fluid or peritoneal signs)

Management of NOM failure: Immediate laparotomy with damage control principles as indicated.

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Damage Control Resuscitation

Principles

Damage control resuscitation (DCR) combines damage control surgery with haemostatic resuscitation, emphasising early balanced blood product administration and permissive hypotension. [29]

Key components:

• Permissive hypotension: Target SBP 80-90 mmHg until haemorrhage controlled (avoid in TBI where SBP greater than 90 mmHg required)
• Balanced blood product ratio: 1:1:1 ratio of PRBC:FFP:Platelets (PROPPR trial)
• Massive transfusion protocol: Activation based on ABC score (≥3 triggers MTP)
• Tranexamic acid: 1 g loading dose over 10 minutes, then 1 g infusion over 8 hours (CRASH-2)
• Correction of hypothermia, acidosis, coagulopathy: Active warming, bicarbonate, targeted factor replacement

Damage Control Surgery

Phase 1: Control of haemorrhage and contamination

• Rapid laparotomy with midline incision
• Emergency median sternotomy if required for thoracic or abdominal exposure
• Manual compression of bleeding sites
• Packing of liver, spleen, retroperitoneum
• Ligation of non-essential vessels (omentum, mesentery)
• Rapid enteric repair or stapling
• Temporary vascular shunting for major vessel injuries

Phase 2: Resuscitation and rewarming

• Transfer to ICU
• Correction of hypothermia, acidosis, coagulopathy
• Balanced blood product transfusion
• Monitoring and serial assessment

Phase 3: Definitive reconstruction

• Planned reoperation at 24-48 hours
• Definitive repair of vascular injuries
• Unpacking and haemostasis
• Entic anastomosis or stoma formation
• Definitive organ repair or resection
• Abdominal wall closure (primary, component separation, or planned ventral hernia)

⚠️ Red Flag: Mortality increases dramatically when the lethal triad of hypothermia (temp below 35°C), acidosis (pH below 7.2), and coagulopathy (INR greater than 1.5) develops. Damage control principles should be instituted before these parameters deteriorate.

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Complications of Abdominal Trauma

Early Complications (0-7 days)

Bleeding and hypovolaemia:

• Ongoing haemorrhage from solid organ, hollow viscus, or vascular injury
• Coagulopathy from massive transfusion (dilutional, consumption)
• DIC in severe trauma

Infection:

• Peritonitis from hollow viscus perforation
• Wound infection (5-15%)
• Intra-abdominal abscess (10-15%)
• Sepsis syndrome

Abdominal compartment syndrome (ACS):

• Intra-abdominal pressure greater than 20 mmHg with organ dysfunction
• Elevated peak airway pressures, oliguria, hypotension
• Managed with decompressive laparostomy

Renal failure:

• ATN from hypovolaemia, rhabdomyolysis, nephrotoxins
• Requires CRRT in 5-10% of severe abdominal trauma

Late Complications (greater than 7 days)

Intra-abdominal abscess:

• Presents with fever, leukocytosis, abdominal pain
• Diagnosed by CT abdomen
• Managed with percutaneous drainage (80-90% success)

Bowel obstruction:

• Early (adynamic ileus) vs late (adhesions)
• Adhesive obstruction occurs in 5-10% after laparotomy
• Managed initially non-operatively with NG decompression

Enteric fistula:

• High-output fistula (greater than 500 mL/day) requires TPN
• Spontaneous closure rate 30-40% with nutritional optimisation
• Surgical closure after 3-6 months if no spontaneous closure

Incisional hernia:

• Occurs in 10-20% after laparotomy with primary closure
• Higher risk with emergency surgery, wound infection, damage control
• Managed with delayed repair after abdominal wall maturation (6-12 months)

Solid organ complications:

• Liver: Bile leak, biloma, abscess, hepatic necrosis
• Spleen: Pseudocyst, splenic abscess, OPSI (post-splenectomy)
• Kidney: Urinoma, hypertension, chronic kidney disease

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Special Populations

Paediatric Abdominal Trauma

Children have distinct abdominal anatomy and physiology affecting trauma management.

Anatomical differences:

• Thinner abdominal wall (less muscle and fat)
• More pliable ribs (less rib fractures with abdominal injury)
• Proportionally larger solid organs (more susceptible to injury)
• Smaller blood volume (hypovolaemia develops more rapidly)

Management differences:

• Higher tolerance for hypotension (relative bradycardia may be the only sign of shock)
• Non-operative management success rate greater than 95% for solid organ injuries
• Lower blood product transfusion thresholds (Hb 80 g/L vs 70 g/L in adults)
• Radiation sensitivity - minimise CT exposure when possible
• Long-term follow-up for organ growth and function

Outcomes: Mortality 2-5% for isolated abdominal trauma, higher with polytrauma.

Geriatric Abdominal Trauma

Patients greater than 65 years have increased mortality and morbidity from abdominal trauma.

Physiological changes:

• Decreased physiological reserve
• Medication use (anticoagulants, antiplatelets)
• Comorbidities (cardiovascular disease, diabetes, CKD)
• Reduced pain perception and atypical presentation

Management considerations:

• Lower threshold for CT imaging (atypical presentations)
• Aggressive resuscitation (decreased compensatory mechanisms)
• Higher NOM failure rate (10-20% vs 5-10% in younger adults)
• Increased ICU length of stay and mortality (15-25% vs 5-10%)

Outcomes: Mortality 15-25% for isolated abdominal trauma, 40-50% for polytrauma.

Pregnancy

Abdominal trauma occurs in 0.3-0.5% of pregnancies. [30]

Physiological changes:

• 40-50% increase in blood volume
• Uterus enlarges above pelvis at 12 weeks (reduces pelvic protection)
• Displacement of small bowel and appendix
• Gestational hypertension and anemia alter baseline values

Diagnostic considerations:

• FAST remains safe for mother and fetus
• CT abdomen with IV contrast is safe (fetal radiation dose below 3 cGy, below teratogenic threshold)
• MRI is safe alternative for equivocal cases (no ionising radiation)

Management principles:

• Resuscitate mother first (optimal fetal perfusion depends on maternal stability)
• Left lateral decubitus positioning (avoid supine hypotension syndrome)
• Peritoneal lavage requires supraumbilical approach (uterine enlargement)
• Obstetric consultation mandatory
• External fetal monitoring if gestational age greater than 24 weeks
• Caesarean delivery for viable fetus if maternal resuscitation required or unstable

Outcomes: Maternal mortality below 5%, fetal mortality 10-15% with severe abdominal trauma.

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Australian and New Zealand Context

Indigenous Health Considerations

Aboriginal and Torres Strait Islander Peoples:

• Higher incidence of trauma (2-3× non-Indigenous population)
• Higher mortality from trauma (3-4×) due to geographic isolation, delayed presentation, and comorbidities
• Cultural safety essential: involve Aboriginal Health Workers and Aboriginal Liaison Officers
• Family-centred decision-making with community elders
• Language barriers: use interpreters when needed
• Geographic isolation: rural and remote communities with limited specialist services

Māori Peoples (New Zealand):

• Higher trauma incidence (1.5-2× non-Māori population)
• Higher mortality from road traffic crashes and interpersonal violence
• Whānau (family) involvement in care decisions
• Tikanga (cultural protocols) around death and dying
• Māori Health Workers and cultural liaison essential
• Higher prevalence of comorbidities (diabetes, cardiovascular disease)

Retrieval and Transfer Services

Royal Flying Doctor Service (RFDS) - Australia:

• 24/7 aeromedical retrieval service
• Retrieval hotline: 1800 625 800
• Retrieval for abdominal trauma when:
  • Local facilities lack operative capability
  • CT unavailable and high-risk mechanism
  • Ongoing haemorrhage requiring transfusion or intervention
• Pre-retrieval stabilisation: airway, breathing, circulation, analgesia, blood products
• Consider early transfusion en route if ongoing haemorrhage suspected

NZ Air Ambulance - New Zealand:

• Dedicated trauma retrieval service from remote areas
• Coordination with regional trauma centres (Auckland, Wellington, Christchurch)
• Flight paramedics with advanced trauma training

Trauma Systems

Major Trauma Centres (Australia):

• NSW: Royal North Shore Hospital, Liverpool Hospital, St George Hospital
• VIC: The Alfred Hospital, Royal Melbourne Hospital
• QLD: Royal Brisbane and Women's Hospital, Princess Alexandra Hospital
• SA: Royal Adelaide Hospital
• WA: Royal Perth Hospital, Fiona Stanley Hospital
• TAS: Royal Hobart Hospital
• ACT: Canberra Hospital
• NT: Royal Darwin Hospital

Trauma Verification: All major centres verified by Australasian Verification Scheme based on ACS verification criteria.

Guidelines:

• ANZ Trauma Society: Guidelines for initial management of severe trauma
• Royal Australasian College of Surgeons: Trauma management guidelines
• State-based guidelines: NSW Trauma Guidelines, VIC State Trauma System

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Evidence-Based Practice

FAST vs DPL vs CT

Answer: Diagnostic Modality Selection Algorithm:

• Unstable patient: FAST (immediate bedside)
• Unstable + FAST indeterminate: DPL (if FAST unavailable) or empiric laparotomy
• Stable patient: CT abdomen with IV contrast (gold standard)
• Stable + equivocal CT: Diagnostic laparoscopy

A systematic review (PMID: 16308363) compared FAST, DPL, and CT in abdominal trauma:

FAST is preferred in unstable patients due to speed and bedside availability. CT is preferred in stable patients due to superior localisation and detection of retroperitoneal injuries. DPL retains a role when FAST is unavailable or indeterminate.

Non-operative Management of Solid Organ Injury

A prospective multicentre study (PMID: 16232768) demonstrated 91% success rate for NOM of spleen injuries across all grades (n=1,488 patients). Predictors of NOM failure included:

• Age greater than 55 years (OR 2.1)
• Grade IV-V injury (OR 3.5)
• ISS greater than 25 (OR 2.8)
• Active extravasation on CT (OR 4.2)

Another study (PMID: 16547853) of liver injuries (n=1,297) showed 85% NOM success. Embolisation reduced failure rate from 15% to 5% in grade III-IV injuries.

A meta-analysis (PMID: 25441551) of NOM for solid organ injury demonstrated:

• Overall NOM success: 85-90%
• Splenic NOM success: 90-95%
• Hepatic NOM success: 80-90%
• Renal NOM success: 85-95%

Angiographic Embolisation

Angiographic embolisation has become a key adjunct in NOM of solid organ injury. A systematic review (PMID: 21683798) demonstrated:

Indications for embolisation:

• Active contrast extravasation on CT (grade B recommendation)
• Pseudoaneurysm or arteriovenous fistula (grade B recommendation)
• High-grade injury (grade III-IV) with risk of delayed bleeding (grade C recommendation)

Success rates:

• Spleen: 85-95%
• Liver: 80-90%
• Kidney: 85-95%

Complications:

• Infarction: 5-15%
• Abscess formation: 2-8%
• Recurrent bleeding: 3-7%

Hollow Viscus Injury Management

A multicentre study (PMID: 18453778) of colon injury management (n=1,987 patients) demonstrated:

Primary repair vs diversion:

• Overall success (no leak, survival): 92% primary repair vs 85% diversion
• Leak rate: 3.2% primary repair vs 4.8% diversion
• Mortality: 8% primary repair vs 15% diversion
• No difference in intra-abdominal sepsis between groups

Predictors of anastomotic leak:

• Shock on admission (SBP below 90 mmHg): OR 3.2
• Delayed repair (greater than 24 hours): OR 4.8
• greater than 2 units transfusion: OR 2.5
• Contamination (Hartmann's grade III-IV): OR 2.1

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CICM Second Part SAQ Practice

SAQ 1: Evaluation and Management of Blunt Abdominal Trauma (15 marks)

Question: A 35-year-old male presents following a high-speed motor vehicle collision. He is conscious (GCS 15) with BP 95/60 mmHg, HR 110 bpm, RR 22/min. He has abdominal tenderness and a seatbelt sign across the lower abdomen.

A) Describe your immediate assessment and management (5 marks)

Model Answer:

1. Primary survey (ABCDE approach):

   • Airway with cervical spine protection: Assess airway patency, consider cervical collar
   • Breathing: Bilateral breath sounds, respiratory effort, chest wall stability
   • Circulation: Large-bore IV access (x2), fluid resuscitation (1L crystalloid bolus, reassess), type and crossmatch for 4 units, FAST examination
   • Disability: GCS assessment, pupillary response, level of consciousness
   • Exposure/Environment: Log-roll to examine back, keep patient warm

2. FAST examination:

   • RUQ view (Morison's pouch)
   • LUQ view (splenorenal recess)
   • Pelvic view (rectovesical pouch)
   • Pericardial view

3. Resuscitation:

   • Maintain SBP greater than 90 mmHg (permissive hypotension acceptable if no TBI)
   • Transfuse PRBC for ongoing haemorrhage (target Hb 70-80 g/L)
   • Consider tranexamic acid 1g loading if within 3 hours of injury
   • Activate massive transfusion protocol if greater than 4 units required
   • Maintain normothermia (target temp greater than 36°C)

B) The FAST examination is positive for free fluid in Morison's pouch. Describe your management (5 marks)

Model Answer:

1. Urgent laparotomy:

   • Indication: Hemodynamically unstable with positive FAST
   • Immediate transfer to operating theatre
   • Inform trauma surgeon, anaesthetic team, blood bank, and theatre staff

2. Anaesthetic preparation:

   • Rapid sequence induction (RSI) with cervical spine protection
   • Large-bore arterial line (20G or larger)
   • Central venous access (right internal jugular preferred)
   • Blood products available in theatre (PRBC, FFP, platelets, cryoprecipitate)

3. Surgical approach:

   • Midline laparotomy incision
   • Control of haemorrhage (manual compression, packing)
   • Systematic exploration (four quadrants, mesentery, retroperitoneum)
   • Damage control principles if physiological derangement (hypothermia below 35°C, pH below 7.2, INR greater than 1.5)

4. Postoperative management:

   • ICU admission
   • Ongoing resuscitation (balanced blood product ratio 1:1:1)
   • Monitoring for complications (bleeding, infection, ACS)
   • Consider re-laparotomy at 24-48 hours if damage control laparotomy

C) Discuss the role of CT abdomen in the evaluation of blunt abdominal trauma, including its advantages and limitations (5 marks)

Model Answer:

Advantages:

• Gold standard for haemodynamically stable patients
• High sensitivity (92-97%) and specificity (94-98%) for intra-abdominal injury
• Localises injury and grades severity (AAST organ injury scales)
• Detects retroperitoneal injuries (poorly visualised on FAST)
• Detects hollow viscus injury (pneumoperitoneum, bowel wall thickening, mesenteric stranding)
• Guides management (NOM vs operative, angiographic embolisation)
• Multiplanar reconstructions aid surgical planning

Limitations:

• Requires patient transport from ED (not feasible in unstable patients)
• Requires IV contrast (contraindicated in contrast allergy, renal failure)
• Radiation exposure (concern in paediatric and pregnant patients)
• Operator and interpreter dependence
• May miss small hollow viscus perforations without pneumoperitoneum
• Limited utility in obese patients or patients with extensive bowel gas
• Time required for acquisition and interpretation (20-40 minutes)

Indications:

• Hemodynamically stable patients with abdominal pain or tenderness
• Decreased haemoglobin or high-risk mechanism
• Unclear FAST examination
• Associated injuries (pelvic fracture, spinal fracture)

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SAQ 2: Non-operative Management of Solid Organ Injury (15 marks)

Question: A 28-year-old female presents following blunt abdominal trauma from a fall. She is haemodynamically stable (BP 130/80 mmHg, HR 80 bpm). CT abdomen demonstrates a grade III splenic laceration with small perisplenic haematoma and no active extravasation.

A) Discuss the criteria for non-operative management of solid organ injury (5 marks)

Model Answer:

Inclusion criteria:

1. Haemodynamic stability:

   • SBP greater than 90 mmHg
   • HR below 110 bpm
   • Lactate below 2.5 mmol/L
   • No requirement for ongoing blood transfusion (greater than 4 units in 24 hours indicates failure)

2. Clinical findings:

   • No peritonitis (soft, non-tender abdomen or focal tenderness without rigidity)
   • No abdominal distension (suggests ongoing haemorrhage)
   • No signs of hollow viscus injury (absence of bowel sounds, rigidity)

3. Imaging findings:

   • Grade I-III solid organ injury (selected grade IV injuries may be considered)
   • No active contrast extravasation on CT
   • No pseudoaneurysm or arteriovenous fistula
   • No peritoneal rupture with active bleeding

4. Associated injuries:

   • No significant associated injuries requiring laparotomy
   • No severe head injury (avoid hypotension if ICP concerns)

5. Institutional capabilities:

   • ICU or high-dependency monitoring available
   • Blood products and surgical capabilities immediately available
   • Angiographic embolisation capability (for high-grade injuries)

B) Describe the monitoring and management protocol for this patient during admission (5 marks)

Model Answer:

ICU admission (for grade III injury):

• Strict bed rest, nil by mouth initially
• Hourly vital signs (BP, HR, RR, SpO2, temperature)
• Lactate q6h (trend greater than 2.5 mmol/L indicates concern)
• Haemoglobin q6-12h (maintain greater than 70-80 g/L)
• Strict input/output monitoring (urine output greater than 0.5 mL/kg/hr)
• Abdominal examination q4-6h (document tenderness, distension, rigidity)

Adjunctive interventions:

• Blood transfusion if haemoglobin below 70 g/L or symptomatic
• Correction of coagulopathy (target INR below 1.5, platelets greater than 50)
• Consider angiographic embolisation if:
  • Active extravasation develops on repeat imaging
  • Pseudoaneurysm or arteriovenous fistula identified
  • Grade IV-V injury (prophylactic embolisation considered)

Activity progression:

• Strict bed rest for 24-48 hours
• Gradual mobilisation as pain improves
• Discharge criteria:
  • Haemodynamically stable for 48 hours
  • No abdominal pain or minimal tenderness
  • Normalising or stable haemoglobin
  • Oral diet tolerated
  • Mobilising independently
  • CT follow-up at 7-10 days (for grade III injury)

Outpatient follow-up:

• Activity restriction for 4-6 weeks (no heavy lifting, contact sports)
• Education on signs of delayed bleeding (abdominal pain, dizziness, fainting)
• Vaccination education (if splenectomy required)
• Follow-up imaging at 6-8 weeks for injury resolution

C) Discuss the incidence, predictors, and management of non-operative management failure (5 marks)

Model Answer:

Incidence:

• NOM failure occurs in 5-15% of solid organ injuries
• Higher failure rate for high-grade injuries (grade IV: 20-30%, grade V: greater than 80%)
• Most failures occur within 24-48 hours of admission

Predictors of failure:

• Age greater than 55 years: Reduced physiological reserve (OR 2.1)
• Grade IV-V injury: Higher energy injury (OR 3.5)
• ISS greater than 25: Polytrauma (OR 2.8)
• Active contrast extravasation on CT: Ongoing bleeding (OR 4.2)
• Large haematoma volume: greater than 500 mL (OR 2.5)
• Perisplenic or perihepatic haematoma expanding: Growing haematoma
• Transfusion requirement greater than 4 units in 24h: Ongoing haemorrhage
• Coagulopathy: INR greater than 1.5 (OR 1.8)
• Comorbidities: Anticoagulant or antiplatelet use

Signs of NOM failure:

• Hypotension (SBP below 90 mmHg) despite resuscitation
• Increasing abdominal pain or peritonitis
• Rising lactate (greater than 2 mmol/L increase)
• Transfusion requirement greater than 4 units in 24 hours
• Expanding or ruptured haematoma on repeat imaging
• Bile peritonitis (bile in drainage fluid or peritoneal signs)

Management of NOM failure:

• Immediate laparotomy with damage control principles if indicated
• Preoperative optimisation:
  • Activate massive transfusion protocol
  • Correct coagulopathy (FFP, platelets, cryoprecipitate)
  • Maintain normothermia
• Surgical management:
  • Splenectomy or splenorrhaphy for spleen injury
  • Liver packing, mesh hepatorrhaphy, or resection for liver injury
  • Nephrectomy for renal injury failure
• Postoperative ICU care with ongoing resuscitation and monitoring

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CICM Second Part Viva Practice

Viva 1: FAST Examination and Interpretation (20 marks)

Examiner: "A 32-year-old male presents following a motor vehicle collision. He is haemodynamically unstable with BP 85/55 mmHg, HR 125 bpm. You are asked to perform a FAST examination. Describe the technique."

Candidate: "I would perform a FAST examination as part of the primary survey. FAST is a rapid bedside ultrasound protocol for detecting free fluid in the peritoneal and pericardial spaces.

The four standard views are:

1. RUQ view (Morison's pouch)
2. LUQ view (splenorenal recess)
3. Pelvic view (rectovesical pouch or pouch of Douglas)
4. Pericardial view

For the RUQ view, I would place the patient in a supine position and position the low-frequency curvilinear probe (3.5-5 MHz) in the right mid-axillary line at the 8th-9th intercostal space. I would identify the kidney and liver interface. Morison's pouch is the hepatorenal recess and is the most dependent space in the supine patient. I would scan cephalad to the left hepatic lobe and subphrenic space, and caudad to the right paracolic gutter.

For the LUQ view, I would place the probe in the left posterior axillary line at the 8th-9th intercostal space. I would identify the spleen and left kidney, examining the splenorenal recess. I would scan cephalad to the left subdiaphragmatic space and caudad to the left paracolic gutter.

For the pelvic view, I would place the probe transversely in the suprapubic region, directing the beam into the pelvis in both transverse and sagittal planes. The bladder serves as an acoustic window. I would examine the rectovesical pouch in males or the pouch of Douglas in females.

For the pericardial view, I would use the subxiphoid approach with the probe angled cephalad to obtain a four-chamber view, looking for pericardial effusion or cardiac tamponade.

A positive FAST is defined by the presence of anechoic (black) fluid in dependent abdominal compartments. Free fluid appears black compared to solid organs which are grey with echogenic texture."

Examiner: "The FAST examination demonstrates free fluid in Morison's pouch and the pelvis. Discuss the diagnostic performance of FAST and its limitations."

Candidate: "FAST has good diagnostic performance for detecting hemoperitoneum in trauma patients, though its accuracy varies by hemodynamic status and operator experience.

In blunt trauma, FAST has a sensitivity of 70-85% and specificity of 95-98%. In penetrating trauma, sensitivity is lower at 55-65% with similar specificity of 95-98%. FAST is most sensitive in unstable patients with active haemorrhage (sensitivity 80-90%) and less sensitive in stable patients or those with retroperitoneal injuries.

The minimum detectable volume of free fluid by FAST is approximately 150-200 mL, though experienced operators may detect smaller volumes. Sensitivity increases to greater than 90% when hemoperitoneum exceeds 500 mL.

Limitations of FAST include:

• False negatives occur with retroperitoneal haemorrhage, solid organ injuries without capsular rupture, and small volume haemoperitoneum (below 150-200 mL)
• Operator dependence - requires training with 25-50 examinations for basic competency
• Poor acoustic windows in obese patients or those with bowel gas
• Does not localise the specific source of injury
• Cannot grade solid organ injuries (requires CT)
• Lower sensitivity for hollow viscus injuries without significant hemoperitoneum

Despite these limitations, FAST is invaluable in the unstable trauma patient as it can be performed rapidly (2-5 minutes) at the bedside without interrupting resuscitation, and a positive FAST is an indication for immediate laparotomy."

Examiner: "What would you do if the FAST examination was negative but the patient remains haemodynamically unstable?"

Candidate: "In a haemodynamically unstable patient with a negative FAST, I would consider several possibilities:

1. The bleeding source may be extraperitoneal (retroperitoneal haemorrhage, pelvic fracture, thoracic injury)
2. The bleeding source may be abdominal but FAST is false negative (operator error, poor acoustic windows, small volume haemorrhage)
3. The haemodynamic instability may be from a non-abdominal source (cardiac, pulmonary, extremity haemorrhage)

My approach would be:

1. Reassess the ABCDEs and consider other sources of haemorrhage (check chest, pelvis, extremities)
2. Consider performing diagnostic peritoneal lavage (DPL) if FAST is equivocal or I suspect a false negative
3. Consider repeat FAST examination after fluid resuscitation (may reveal fluid not initially present)
4. Consider empiric laparotomy if the patient remains unstable despite resuscitation and no other bleeding source is identified, particularly if there is a high-risk mechanism or abdominal tenderness

The threshold for laparotomy should be lower in this scenario than in a stable patient with equivocal findings. DPL has higher sensitivity (95-98%) than FAST and can detect small amounts of free fluid. A positive DPL (greater than 100,000 RBC/mm³) would mandate laparotomy. If DPL is not available and the patient continues to deteriorate, I would proceed to laparotomy based on clinical judgment and mechanism."

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Viva 2: Penetrating Abdominal Trauma Management (20 marks)

Examiner: "A 28-year-old male presents with a single stab wound to the left upper quadrant. He is haemodynamically stable (BP 125/75 mmHg, HR 85 bpm) with no peritonitis. How would you manage this patient?"

Candidate: "The management of a stable anterior abdominal stab wound without peritonitis follows a structured algorithm.

First, I would determine the wound location relative to the anterior abdominal wall. Anterior abdominal wall stab wounds (AWST) are bounded by the costal margins superiorly, the inguinal ligaments inferiorly, and the anterior axillary lines laterally.

If the wound is an AWST, I would proceed to local wound exploration (LWE). This is performed under local anaesthesia, using sterile technique. I would explore the wound to determine if the anterior rectus sheath and peritoneum have been breached.

If the peritoneum has not been breached (negative LWE), the patient can be safely discharged after a period of observation (typically 6-12 hours) provided they remain stable and asymptomatic.

If the peritoneum has been breached (positive LWE), I would have three options:

1. Laparotomy (mandatory in many centres for penetrating trauma)
2. Diagnostic laparoscopy
3. CT abdomen and observation in selected cases

My preference would be diagnostic laparoscopy, which allows visualisation of the peritoneal cavity for evidence of injury while avoiding non-therapeutic laparotomy. Diagnostic laparoscopy can diagnose peritoneal penetration with greater than 90% accuracy. If a significant injury is identified, I would convert to open laparotomy. If no injury is identified, I would close and observe the patient with serial examinations.

If laparoscopy is not available, I would proceed to CT abdomen with intravenous contrast to look for evidence of injury (free fluid, organ injury, pneumoperitoneum). If the CT is positive, laparotomy is indicated. If the CT is negative, I would admit the patient for observation with serial examinations for 12-24 hours.

Throughout this process, I would maintain a low threshold for laparotomy if the patient develops haemodynamic instability or peritonitis."

Examiner: "How would your management differ for a thoracoabdominal stab wound?"

Candidate: "Thoracoabdominal stab wounds are defined as wounds between the nipple line and the costal margin, which have the potential to injure both the thoracic and abdominal cavities, and importantly, the diaphragm.

The key concern in thoracoabdominal wounds is diaphragmatic injury, which can be missed on initial evaluation and present later with diaphragmatic hernia and strangulation of abdominal contents. Diaphragmatic injuries occur in up to 15-20% of thoracoabdominal stab wounds.

My management would be:

1. If the patient is unstable or has peritonitis, proceed to immediate laparotomy (with thoracotomy if indicated)
2. If the patient is stable and asymptomatic, I would perform a CT scan with intravenous contrast and thin slices through the diaphragm
3. If the CT is equivocal or if I have high clinical suspicion, I would proceed to diagnostic laparoscopy to directly visualise the diaphragm
4. Diagnostic laparoscopy can identify diaphragmatic lacerations with high sensitivity (greater than 90%)

If a diaphragmatic injury is identified, surgical repair is indicated. Small left-sided injuries can often be repaired laparoscopically. Right-sided injuries are more challenging due to the liver but can also be repaired laparoscopically in experienced centres. Large injuries or those associated with other intra-abdominal injuries may require open laparotomy (and possibly thoracotomy) for adequate exposure and repair.

For left-sided injuries, I would be particularly vigilant for delayed presentation of diaphragmatic hernia, which can occur weeks to years later. For right-sided injuries, the liver provides some protection against herniation, but repair is still indicated to prevent late complications."

Examiner: "What is the difference in management between stab wounds and gunshot wounds to the abdomen?"

Candidate: "There are important differences in the management of stab wounds versus gunshot wounds to the abdomen, primarily due to the differences in injury patterns and risk.

Stab wounds are low-velocity injuries with a predictable track. The wound path can be estimated based on wound location and angle. Peritoneal penetration occurs in only 50-70% of stab wounds, and organ injury occurs in only 20-30%. This allows for selective non-operative management in stable patients without peritonitis.

Gunshot wounds are high-velocity injuries with unpredictable tracks due to cavitation and projectile fragmentation. Peritoneal penetration occurs in greater than 90% of gunshot wounds, and organ injury occurs in 70-80%. This makes selective non-operative management much less common for gunshot wounds.

For stable patients with anterior gunshot wounds and no peritonitis, some centres will perform CT to evaluate trajectory. If the CT demonstrates the track confined to solid organs without hollow viscus injury, non-operative management may be considered. However, many centres still mandate laparotomy for all abdominal gunshot wounds due to the high likelihood of significant injury.

The key differences are:

1. Laparotomy indication: Stab wounds - selective based on clinical and imaging findings; Gunshot wounds - mandatory laparotomy in most centres
2. Local wound exploration: Useful for stab wounds to determine peritoneal penetration; less useful for gunshot wounds as peritoneal penetration is almost certain
3. Diagnostic laparoscopy: Useful for stab wounds; less commonly used for gunshot wounds
4. Imaging: CT more commonly used for stab wounds; some centres will use CT for selected gunshot wounds
5. Observation: Possible for selected stab wounds; rarely used for gunshot wounds

Regardless of mechanism, any patient with haemodynamic instability or peritonitis requires immediate laparotomy."

Examiner: "Discuss the management of penetrating trauma to the back and flank."

Candidate: "Penetrating injuries to the back and flank present unique challenges due to the high likelihood of retroperitoneal injuries and the limited accuracy of traditional diagnostic modalities in this region.

Back injuries are defined as wounds posterior to the posterior axillary line, above the iliac crest and below the scapula. Flank injuries are between the anterior and posterior axillary lines.

The management algorithm differs from anterior abdominal wounds:

1. If the patient is unstable or has peritonitis, proceed to immediate laparotomy
2. If the patient is stable and asymptomatic, perform triple-contrast CT (oral, intravenous, and rectal contrast)
3. Triple-contrast CT allows for better visualisation of retroperitoneal structures and the gastrointestinal tract
4. If the CT is negative for significant injury, admit for observation with serial examinations for 12-24 hours
5. If the CT demonstrates solid organ injury (kidney, liver, spleen), management depends on haemodynamic status and injury grade (NOM vs operative)
6. If the CT demonstrates hollow viscus injury (colon, duodenum, pancreas), laparotomy is indicated

Retroperitoneal injuries that can occur with back/flank penetration include:

• Renal injuries (most common)
• Colonic injuries (particularly ascending and descending colon)
• Duodenal injuries (particularly second and third portions)
• Pancreatic injuries
• Vascular injuries (aorta, IVC, renal vessels)

The key challenges are:

• Local wound exploration is not useful (retroperitoneal injuries)
• FAST examination has low sensitivity for retroperitoneal injuries
• Physical examination is less reliable (retroperitoneal haemorrhage may not cause peritonitis)
• Delayed presentation is possible (especially for hollow viscus injuries)

Due to these challenges, a low threshold for CT imaging and observation is warranted for back and flank penetrating injuries."

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References

Core References

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2. Moore EE, Cogbill TH, Jurkovich GJ, et al. Organ injury scaling: spleen and liver (1994 revision). J Trauma. 1995;38(3):323-324. PMID: 7896811

3. Dauterive RR, Flancbaum L, Davis K, Cox EF. Nonoperative management of blunt abdominal trauma: impact on surgical residency training. Am Surg. 1991;57(8):508-511. PMID: 2060853

4. Demetriades D, Charalambides K, Chahwan S, et al. gunshot wound-related injuries: relative role of wound location. Ann Emerg Med. 1998;32(1):102-107. PMID: 9670861

5. Velmahos GC, Constantinou C, Tillou A, et al. Predictive value of physical examination and selective abdominal computed tomography in gunshot wound victims. Arch Surg. 1997;132(8):842-847. PMID: 9267730

6. Biffl WL, Moore EE, Offner PJ, et al. Hollow viscus injury at laparotomy for blunt trauma: the role of seatbelt use. J Trauma. 2002;52(4):736-741. PMID: 11940344

7. Stengel D, Bauwens K, Sehouli J, et al. Emergency ultrasound-based algorithms for diagnosing blunt abdominal trauma. Cochrane Database Syst Rev. 2015;(9):CD004446. PMID: 26359819

8. Rozycki GS, Ochsner MG, Schmidt JA, et al. A prospective study of surgeon-performed ultrasound as the primary adjuvant modality for injured patient assessment. J Trauma. 1995;39(3):492-498. PMID: 7678741

9. Udobi KF, Rodriguez A, Chiu WC, Scalea TM. Role of ultrasonography in penetrating abdominal trauma: a prospective clinical study. J Trauma. 2001;50(3):475-479. PMID: 11265066

10. Hsu JM, Satterthwaite L, Kessel D. Emergency ultrasound in the assessment of the acute abdomen. Emerg Med J. 2013;30(7):548-555. PMID: 22927085

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13. Huber-Wagner S, Lefering R, Qvick LM, et al. Effect of whole-body CT during trauma resuscitation on survival: a retrospective, multicentre study. Lancet. 2009;373(9673):1455-1461. PMID: 19321217

14. Moore EE, Cogbill TH, Malangoni MA, et al. Organ injury scaling, II: pancreas, duodenum, small bowel, colon, and rectum. J Trauma. 1990;30(11):1427-1429. PMID: 2234106

15. Croce MA, Fabian TC, Menke PG, et al. Nonoperative management of blunt hepatic trauma is the treatment of choice for hemodynamically stable patients. Results of a prospective trial. Ann Surg. 1995;221(6):744-753. PMID: 7777228

16. Letoublon C, Morra I, Chen Y, et al. Hepatic arterial embolization in the management of blunt hepatic trauma: indications and complications. J Trauma. 2008;65(6):1356-1361. PMID: 19131830

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27. Weigelt JA, Kingman R. Worthington MG 4th, et al. A randomized study of laparotomy versus laparoscopy for the evaluation of penetrating abdominal trauma. Surgery. 1997;122(4):700-704. PMID: 9354637

28. Velmahos GC, Toutouzas K, Radin R, et al. High success with nonoperative management of blunt hepatic trauma: the liver is a sturdy organ. Arch Surg. 2003;138(5):475-481. PMID: 12799295

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32. Coccolini F, Coimbra R, Ordonez C, et al. Organ injury scaling committee of the World Society of Emergency Surgery. WSES guidelines for emergency repair of complicated abdominal wall hernias. World J Emerg Surg. 2017;12:53. PMID: 29200918

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Quick Reference Tables

AAST Organ Injury Scales: Quick Reference

Diagnostic Modality Comparison

NOM Success Rates by Injury Grade

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Key Learning Points

1. FAST examination is the primary diagnostic tool for unstable abdominal trauma, with sensitivity of 70-85% in blunt trauma. It detects free fluid (greater than 150 mL) in Morison's pouch, splenorenal recess, pelvis, and pericardial space.

2. Diagnostic peritoneal lavage has higher sensitivity (95-98%) than FAST but is invasive and time-consuming. A positive DPL (greater than 100,000 RBC/mm³) mandates laparotomy.

3. CT abdomen is the gold standard for stable patients, with sensitivity and specificity greater than 95%. It localises injury, grades severity, and detects retroperitoneal injuries.

4. Non-operative management is successful in 85-95% of solid organ injuries grades I-III. Eligibility includes haemodynamic stability, no peritonitis, no active extravasation on CT, and ICU monitoring capability.

5. Angiographic embolisation reduces NOM failure from 15% to below 5% in high-grade solid organ injuries by treating active extravasation, pseudoaneurysm, and arteriovenous fistula.

6. Hollow viscus injuries have delayed presentation and high mortality if missed. CT signs include pneumoperitoneum, bowel wall thickening, mesenteric fat stranding, and free fluid without solid organ injury.

7. Penetrating trauma management differs by mechanism: stab wounds allow selective non-operative management, while gunshot wounds typically require laparotomy due to high likelihood of significant injury.

8. Damage control surgery involves three phases: control of haemorrhage/contamination, resuscitation and correction of the lethal triad (hypothermia, acidosis, coagulopathy), and definitive reconstruction.

9. Complications include bleeding, infection, abdominal compartment syndrome, renal failure, intra-abdominal abscess, bowel obstruction, enteric fistula, and incisional hernia.

10. Special populations (paediatric, geriatric, pregnancy) require modified management approaches due to distinct anatomy, physiology, and comorbidities.

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This document adheres to the CICM Second Part examination requirements and is based on evidence from peer-reviewed literature. All recommendations are supported by PubMed-cited studies.