Abdominal Trauma

Dr.Janet Lee

Department of Surgery

Mechanism of Injury

Blunt injury

Penetrating injury

Blast injury

Iatrogenic injury

Blunt injury

Commonest mode

Frequently multi-system injury

Abdominal injury accounts for 10% blunt trauma death

Road traffic accident

Mechanism of blunt injury

Direct impact

Deceleration and rotational forces

Liver and spleen are the most commonly injured organs

Bowel injury (acute increase in intraluminal pressure / shearing at mesentery)

Penetrating injury

High velocity

Gunshot wounds

Low velocity

Stab wounds / low-velocity missiles

Mechanism of penetrating injury

Stab wounds

Injury confined to the tract of wounding

Gunshot wounds

Depends on the energy transferred

Penetration is accompanied by shock wave with cavitating effect (spiral path of motion)

Blast injury

Positive and negative pressure waves

Cause associated pressure changes in bowel gas (blowout)

Victim thrown by the force of pressure waves

Shrapnel

Iatrogenic injury

Uncommon

Laparoscopy

Endoscopy

Primary survey and resuscitation

Objectives of this phase:To identify and correct any immediate life-threatening conditionsTo anticipate problems

The activities are performed simultaneously with enough personnelA- Airway and cervical spine controlB- BreathingC- Circulation with haemorrhage controlD- DisabilityE- Exposure

Airway and C-spine control

C-spine injury should be assumedNo attempt should be made to turn the patient’s head to one side unless C-spine injury has been ruled outOxygen provided once airway cleared and securedBeware of aspiration

Breathing

Anticipate SIX immediately life-threatening thoracic conditions:1. Airway obstruction2. Tension pneumothorax3. Open chest wound4. Massive haemothorax5. Flail chest6. Cardiac tamponade

Respiratory rate and effort are both sensitive markers of underlying lung pathology (both should be monitored)

Circulation

Key objectives of circulatory care:

Stop haemorrhage

Assess hypovolaemia

Vascular assess

Appropriate fluid resuscitation

Stop haemorrhage

Direct pressure (external haemorrhage)Long bone fractures be splintedPelvic bindingPneumatic anti-shock garment (PASG)Pelvic fracture may need external fixationTry to avoid:Vessel clampingTourniquets (distal ischaemia)

Assessment for hypovolaemia

Skin (colour, clamminess and capillary refill)Heart rate and BPPulse pressureConscious levelECG monitoringSearch for common sites of occult bleeding:ChestAbdomen / RetroperitoneumPelvisLong bonesSplints and dressings

Vascular assess

Large bore IV catheter

20ml blood taken for grouping and x-match and for e- + full blood count

Femoral line / venous cut down / intra-osseous access (if peripheral IV assess failed)

Central venous line insertion is not essential for initial resuscitation

Fluid resuscitation

Initial fluid resuscitation:

2L warmed crystalloid

Responder: Give maintenance fluids once initial deficit replaced

Transient responder: Deteriorate due to continued haemorrhage, give blood and urgent surgical opinion

Non-responder: Ongoing haemorrhage at a greater rate, need urgent surgical opinion

Resuscitation end-point

Administer sufficient fluids to maintain perfusion of essential organsSBP 80mmHg (previously normotensive)Equivalent to a palpable radial pulsePermissive hypotension to minimizeOngoing haemorrhageDisruption of established thrombusDilution of clotting factorsMonitored vitals:Resp rate, SaO2, HR, BP, Pulse pressure, Cardiac monitoring, Temp, Urine output, GCS

Urethral injury

Far more common in male patients5-25% patients with pelvic fractures have an associated urethral injurySymptoms:Perineal painDysuriaFailure to voidSigns:Blood at urethral meatusBruising around scrotumHigh-riding prostate

Urethral injury

Urinary catheterization is contraindicated:

Conversion of partial to complete transection

Stricture formation

Introduce infection

Diagnosis confirmed by retrograde urethrogram

Disability

Baseline neurological examination:AVPU responseGlasgow comma scale (if time permits)Pupillary responseRepeated assessment to look for signs of deteriorationCommon causes of deterioration:HypoxiaHypovolaemiaHypoglycaemiaRaised ICP

Exposure

Trauma victims must be kept warm and covered with blankets when not examined

Log-roll

Assess the spine from skull base to coccyx

Examine the back for signs of injury

Rectal examination

Secondary survey (abdominal examination)

Key objective:To decide if laparotomy is neededDetailed examination of the abdomen, pelvis and perineumNote for bruising and woundsCover exposed bowel loops with warm NS soaked gauzeGastric tube to decompress distended stomach to facilitate abdominal examination and reduce risk of aspiration

Physical examination

Most alert patients will have abdominal tenderness

Initial PE in blunt abdominal trauma is only 65% accurate

Altered mental state (drugs, alcohol, HI, etc)

Sensory abnormalities (spinal cord injury)

Distracting injuries (extra-abdominal)

Serial examinations are often more important

Physical findings

Distension

Usually 20 to ileus or pneumoperitoneum or

haemoperitoneum

Bruising

Palpation

Lower ribs fractureAbdominal tenderness, guarding or reboundPelvic stabilityLumbar spine for tendernessRectal examinationAnal toneProstate position (?high riding)Blood over examination glove

Plain radiographs

CXR

The most important plain film

Obvious intra-thoracic and diaphragmatic injuries

Pelvis (AP view)

C-spine (Lat view) make sure C1-C7 are well shown

AXR seldom helpful (not routine)

Laboratory studies

Laboratory tests play limited role in the diagnosis of IAI (normal test never R/O IAI)

Baseline Hb level

Acid-base status

Amylase (not sensitive / specific)

Urinalysis (gross haematuria is the most consistent sign of serious renal injury)

Diagnostic peritoneal lavage

Before the introduction of DPL ~20% patient with abdominal trauma died of unrecognized injurySensitive 97-99%Fast (5-15 min)False +ve 1.4%Complication rate 1%No information on retroperitoneal organsNot sensitive to detect diaphragmatic or bladder injuries (these result in minimal bleeding)

Contraindication of PDL

Absolute

Obvious need for laparotomy

Evisceration

Relative

Pregnancy (>12 wks)

Previous abdominal surgery

Criticism of PDL

Overly sensitive

Non-bleeding solid organ injuries (which can be managed conservatively)

Non-therapeutic laparotomies

Best preserved for hypotensive, unstable, multi-injured patients

Techniques

Closed percutaneous

Semi-closed

Open

1 Liter of warm normal saline is instilled in adults

15 ml/kg in children

A minimum of 300 ml of lavage fluid must return to give a representative sample

Positive results of DPL

10ml gross blood or bowel contents with initial aspirationRBC count >100,000 cells/ml in blunt traumaRBC count >10,000 cells/ml in stab woundsRBC count >5000 cells/ml in penetrating chest traumaWBC count >500 cells/ml

Ultrasound

Kristensen et al first reported the use of USG in abdominal trauma in 1971Non-invasive and inexpensivePortable (bed side)No radiation / contrast requiredWell tolerated (excellent for unstable patients)Quick (within 3 mins in experienced hands)Serial examination easy to performBest screens for haemoperitoneum

FAST technique

Focused Abdomianl Sonography for Trauma (Rozycki et al)A standard approach which involves imaging a limited number of US windows to detect fluid:RUQ (Morison’s pouch)LUQ (to view the spleen)Pelvis (Douglas pouch)Pericardial window to assess for pericardial effusion (epigastric)

Reliability of FAST

Sensitivity 93.4%

Specificity 98.7%

Accuracy 97.5%

A collected review of ~5000 patients (with FAST performed by surgeons)Rozycki and Shackford J Trauma 1996; 28: 483-9

Results interpretation

Unstable patients with a +ve US requires laparotomy

Stable patients can be followed by serial US or employ CT for further evaluation

Limitations

Operator dependent

Uncooperative / agitated patients

Obesity

Surgical emphysema

Ileus

Cannot assess retroperitoneal organs

Like CT, US is insensitive for bowel injury

Poor sensitivity for penetrating trauma

Abdominal computed tomography

Introduced in late 1970s for trauma management

CT quantifies intraperitoneal blood and grades organ injury

IV and oral contrast

Accuracy is extremely reader-dependent

Modern spiral scan requires 3-5 mins

Dome of diaphragm to pelvis

Precautions

Haemodynamically stable

More time consuming than DPL / FAST

30-50 min

Adequate monitoring

Resuscitation facilities must be available in the CT room

Diagnostic laparoscopy

DL is a relatively new investigationLittle evidence to support its role in blunt traumaNot sensitive in Dx hollow viscus and retroperitoneal injuryPenetrating trauma (stab wounds) in stable patient100% sensitivity for identification of peritoneal penetrationMost effective for diagnosing ruptured diaphragm

Limitation of DL

Time consuming

Invasive

General anaesthetic

Difficult to exclude hollow viscus perforation

Management approach for blunt abdominal trauma

Unstable patient with abdominal signOperationUnstable patient with uncertain abdominal injuryDPL or FASTStable patient with associated severe injuriesDPL or FASTStable patient with associated minor injuries and equivocal abdomenCT scanStable patient with abdominal signsCT scan (allowing non-operative Tx if appropriate)

Stab wounds

Penetrates peritoneum in 2/3 casesOnly 50-70% of these have significant visceral or vascular injurySelective laparotomies to reduce morbidity and hospital stay in haemodynamically stable patientsDiagnostic aids:Wound explorationDPLLaparoscopySerial examinations

Lumbar and flank wounds

Significantly less risk (<15%) for intra-abdominal injuries than those with anterior woundsA more selected approach is warrantedContrast enhanced CT scan combined with serial examinations is recommendedRenal injuries occur in 6-8%

Management approach for penetrating abdominal trauma

Sensitivity of CT or US are far too low to exclude intra-abdominal injuryStab woundsPeritoneal penetration LaparotomyDiagnostic laparoscopy LaparotomyWound exploration LaparotomyGunshot woundsObligatory laparotomyDiagnostic laparoscopy Laparotomy

Incidence of IAI requiring exploratory laparotomy

Blunt % Penetrating %

Spleen 47 7

Liver 51 28

Pancreas / Duodenum

10 11

Colon 5 23

Stomach / Small bowel

9 42

Management “Prioritization”

Concurrent head injuries

An exsanguinating abdominal injury demands a laparotomy to control bleeding before assessment of the HI

Pelvic fracture

Rapid application of external fixator to stabilize the pelvis before laparotomy

Non-operative management of solid organ injury

Increasing evidence to support non-operative Mx

Parallels with the wide-spread use of CT

Clinical criteria (not CT grading) are used for decision making

Must be continuously monitored in HDU or ICU setting

Criteria for non-operative Mx

Solid organ injury shown on CT scan

Minimal abdominal signs

Haemodynamically stable

Requires <2 units of blood

HDU or ICU available

Surgeons committed for repeated evaluation

Success rate of non-operative Mx

Liver

50-80%

Spleen

93% for minor injuries

Renal

Majority can be Mx conservatively unless there is injury to renal pedicle or massive damage

Intervention radiology

Angiography embolization

Both diagnostic and therapeutic

Common use

Pelvic fracture with bleeding uncontrolled by fixation

Solid organ injury

Damage control surgery

10% trauma patients cannot tolerate definitive procedure at initial laparotomy

Survival benefit demonstrated with the use of “damage control” approach

Control bleeding

Injured bowel stapled without anastomosis

Solid organ injury packed

Abdomen rapidly closed with towel clips or plastic bag

Indications for damage control

Hypothermia 350C

Acidosis pH <7.2

Coagulopathy

Definitive surgery is deferred for 24-48 hrs when resuscitation in ICU has corrected these physiological parameters

Abdominal compartment syndrome

ACS: A group of adverse progressive physiological effects of raised intra-abdominal pressureAbdominal trauma is the commonest causePressure required to precipitate ACS is unknown (varies with individuals)Most will require decompression at 25-35 cmH2O

Predisposing factors in trauma patients

Massive intra-abdominal bleeding

Visceral edema (ischaemia-reperfusion)

Vigorous fluid resuscitation

Surgery

Packing

Pathophysiology

Diaphragmatic splinting (Resp)

Pressure on IVC (Decreases venous return and thus cardiac output)

Oliguria (Direct renal compression +/- reduced systemic blood flow)

The condition is fatal unless treated before irreversible physiological insult occurs

Major systems affected

Pulmonary

Cardiovascular

Renal

Treatment of ACS

Urinary manometry to monitor the intraabdominal pressureNasogastric decompressionAbdominal decompressionControl of haemorrhageEvacuation of gauze packs and bloodDelayed wound closure (temporary plastic wrap)Ventilatory support till definitive closure (optimally in 2-3 days time)