Abdominal Compartment Syndrome

Also known as: ACS

Abdominal compartment syndrome is sustained elevation of intra abdominal pressure above 20 mmHg associated with new organ dysfunction or failure. It is distinct from intra abdominal hypertension, defined as sustained or repeated intra abdominal pressure of at least 12 mmHg.

Intra abdominal hypertension is graded:

Grade I: 12 to 15 mmHg
Grade II: 16 to 20 mmHg
Grade III: 21 to 25 mmHg
Grade IV: above 25 mmHg

Pressure impairs venous return, diaphragmatic excursion, renal perfusion, mesenteric perfusion and abdominal organ blood flow. The result may be refractory hypoxaemia, oliguria, hypotension, bowel ischaemia and multiorgan failure.

Typical settings include massive fluid resuscitation, major trauma, intra abdominal haemorrhage, pancreatitis, bowel oedema, abdominal sepsis, ileus, retroperitoneal haemorrhage, burns and tight abdominal closure.

Suspect it in a critically ill patient with a tense distended abdomen plus otherwise unexplained deterioration.

Important manifestations are:

Increasing ventilatory pressures or worsening oxygenation
Oliguria or progressive acute kidney injury
Hypotension or increasing vasopressor requirement
Increasing abdominal tension and distension
Rising lactate or metabolic acidosis
Reduced cardiac output

Clinical examination alone is unreliable. A tense abdomen supports the diagnosis but cannot quantify intra abdominal pressure.

Bladder pressure measurement: reference standard for intermittent intra abdominal pressure measurement. Instil no more than 25 mL sterile saline, measure supine at end expiration with relaxed abdominal musculature and zero the transducer at the midaxillary line.

Diagnosis requires both:

Intra abdominal pressure above 20 mmHg plus new organ dysfunction.

Abdominal perfusion pressure is:

Mean arterial pressure minus intra abdominal pressure.

CT may identify the cause, such as haemoperitoneum, bowel distension or retroperitoneal collection, but abdominal compartment syndrome is a physiological diagnosis and imaging must not delay decompression in a deteriorating patient.

Begin treatment as soon as clinically significant intra abdominal hypertension is identified.

Reduce intraluminal volume with nasogastric decompression for gastric distension and rectal or colonic decompression where appropriate. Treat ileus and evacuate bladder obstruction.

Drain intra abdominal fluid, ascites or collections percutaneously when this can meaningfully reduce pressure.

Optimise analgesia and sedation. Short term neuromuscular blockade can reduce abdominal wall muscle tone in selected ventilated patients, but it is a temporising measure rather than definitive therapy.

Avoid continuing excessive crystalloid once initial resuscitation is complete. Correct positive fluid balance where clinically possible using judicious diuresis or renal replacement therapy if otherwise indicated.

Ensure adequate systemic perfusion. Hypotension worsens abdominal organ perfusion even when intra abdominal pressure remains unchanged.

Established abdominal compartment syndrome with progressive organ failure despite medical decompression requires urgent decompressive laparotomy.

The abdomen is usually left temporarily open because immediate tight fascial closure risks recurrent compartment syndrome. Negative pressure temporary abdominal closure is commonly used.

Aim for definitive fascial closure as early as safely possible once resuscitation has stabilised, source control is achieved, bowel viability is established and there is no residual concern for recurrent compartment syndrome.

Clinical toolsCalculators

BMI GCS EDD Parkland Formula

Corrected Sodium Corrected Calcium Anion Gap Creatinine Clearance Insulin Calculations qSOFA Wells PE Wells DVT CHA₂DS₂-VASc HAS-BLED CURB-65 Centor/McIsaac

Femoral Neck Fracture

Also known as: Hip fracture, Intracapsular hip fracture

A femoral neck fracture is an intracapsular fracture between the femoral head and intertrochanteric region.

The intracapsular location is clinically important because the femoral neck has limited periosteal healing and displacement can disrupt branches of the medial femoral circumflex artery supplying the femoral head.

Major complications are:

Osteonecrosis of the femoral head
Nonunion
Femoral neck shortening
Fixation failure

In younger patients the priority is preservation of the native femoral head.

In older patients with displaced fractures the priority is reliable immediate reconstruction and mobilisation, usually with arthroplasty.

Anatomical classification

Subcapital

Immediately below the femoral head.

Transcervical

Through the midportion of the femoral neck.

Basicervical

At the base of the neck close to the intertrochanteric region.

Basicervical fractures behave more like extracapsular mechanically unstable fractures and may require stronger sliding or fixed angle constructs.

Garden classification

Based primarily on displacement on the AP radiograph.

Garden I

Incomplete fracture
Usually valgus impacted

Garden II

Complete fracture
Nondisplaced

Garden III

Complete fracture
Partially displaced
Some residual contact between head and neck

Garden IV

Complete fracture
Fully displaced

For treatment purposes:

Garden I and II = nondisplaced
Garden III and IV = displaced.

Pauwels classification

Based on inclination of the fracture line from horizontal.

Type I: less than 30°

Predominantly compressive forces.

Type II: 30° to 50°

Increasing shear.

Type III: greater than 50°

Highly vertical, shear dominant fracture with greater mechanical instability and nonunion risk.

Older patients typically present after a low energy fall with groin pain and inability to bear weight.

A displaced fracture produces:

Shortened limb
External rotation
Pain with any hip movement

A valgus impacted fracture can be surprisingly subtle and some patients remain able to walk.

Young patients usually sustain these fractures through high energy trauma and require assessment for additional injuries.

Initial management

Provide adequate analgesia.

A fascia iliaca or femoral nerve block can markedly reduce opioid requirements in older patients.

Correct reversible physiological problems promptly rather than delaying surgery unnecessarily.

For geriatric hip fracture, operate on the day of admission or the following day where possible.

Young or physiologically young patient

Preserve the femoral head whenever feasible.

A displaced femoral neck fracture requires urgent anatomical reduction and stable internal fixation.

Reduction goals are:

Restore normal neck shaft angle
Correct rotational displacement
Avoid varus
Restore posterior cortical alignment

Poor reduction cannot be compensated for by excellent hardware.

If acceptable reduction cannot be obtained closed, perform open reduction rather than accepting malalignment.

Garden I or II, low angle fracture

Multiple parallel cannulated screws can provide adequate fixation.

Basicervical or Pauwels III fracture

A sliding hip screw, femoral neck system or another fixed angle construct generally provides greater resistance to vertical shear than isolated parallel screws. A supplementary antirotation screw may be used with selected constructs.

Severe posterior comminution increases instability.

Protected weight bearing is usually required after fixation in younger patients until sufficient healing occurs.

Older patient with nondisplaced fracture

Garden I and II fractures are commonly treated with internal fixation using cannulated screws or another low morbidity fixation system.

Very elderly patients with substantial posterior tilt, poor bone quality or a high likelihood of fixation failure require individual consideration because arthroplasty may sometimes provide a more reliable outcome.

Older patient with displaced fracture

Garden III or IV fracture should usually undergo arthroplasty rather than internal fixation.

Use hemiarthroplasty for patients with lower functional demand, significant frailty or limited independent life expectancy.

Consider total hip arthroplasty when the patient:

Previously walked independently outdoors with no more than a stick
Is medically suitable for the larger operation
Is expected to remain independently functional for more than approximately 2 years.

Use a cemented femoral stem for hip fracture arthroplasty in most older adults unless a specific contraindication exists.

Postoperative care

Aim for immediate or early weight bearing as tolerated after stable arthroplasty or appropriate geriatric fixation.

Mobilise beginning the day after surgery where possible.

For fragility fractures of the hip or proximal femur, provide pharmacological venous thromboembolism prophylaxis for approximately 1 month when bleeding risk permits. LMWH can begin approximately 6 to 12 hours after surgery.

Investigate and treat osteoporosis because the fracture is frequently a sentinel fragility event.

Abdominal Compartment Syndrome

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management