Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

all patients

1st line – treatment of underlying cause

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ACUTE
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all patients
1st line – 

treatment of underlying cause

A primary cause such as abdominal bleeding or trauma, packing, intra-abdominal infection/inflammation, ileus, pneumoperitoneum, or bowel ischemia should be managed; most of these require surgical intervention, which may already have been performed prior to the development of ACS.

Secondary causes are almost always related to excessive fluid resuscitation and massive blood transfusions, which require optimization of fluid balance. Escharotomies may need to be performed in patients with thermal injuries.

Plus – supportive care with monitoring

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ACUTE
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all patients
Plus – 

supportive care with monitoring

Treatment recommended for ALL patients in selected patient group

All patients require regular monitoring of intra-abdominal pressure and oxygen saturations.

Adequate analgesia and sedation should be provided. In addition to providing pain relief, this helps relax the abdominal musculature and improves abdominal compliance.

The bed tilt should ideally be <30° to improve abdominal wall compliance. Prone positioning should be avoided. The reverse Trendelenburg position (patient placed flat, head up, feet down) improves lung and abdominal compliance, but may not be tolerated by some patients due to a drop in mean arterial pressure or cardiac output.[10]

Tight or constrictive clothing places pressure on the abdomen and should be removed. Restrictive bandages causing tension on the abdominal cavity should also be removed where possible.

The need for organ support should be assessed in all patients.

Primary options

morphine sulfate: 2.5 to 10 mg intramuscularly every 2-4 hours when required; or 0.8 to 10 mg/hour intravenously via infusion pump

Plus – optimized fluid management

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ACUTE
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all patients
Plus – 

optimized fluid management

Treatment recommended for ALL patients in selected patient group

Excessive fluid resuscitation should be avoided, and employing a restrictive fluid resuscitation strategy has clear benefits that outweigh aggressive fluid removal in the setting of elevated IAP.[24] Colloids and hypertonic fluids should be used rather than crystalloids. To return fluid to the intravascular compartment, 25% human albumin can be given, although its effectiveness has not been confirmed in clinical trials.

Diuretic therapy is successful in reducing fluid overload, but care must be taken to avoid exacerbating shock in critically ill patients who are hypovolemic. It is better to start with a higher dose so that effective diuresis is achieved quickly; excessive fluid loss is easier to correct than excessive fluid administration. Diuretics should be administered via infusion pump at a controlled rate to avoid ototoxicity.

Primary options

furosemide: 20-40 mg intravenously initially, followed by 10-160 mg/hour continuous infusion

OR

bumetanide: 1 mg intravenously initially, followed by 0.5 to 2 mg/hour continuous infusion

Plus – mechanical evacuation of intraluminal contents

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ACUTE
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all patients
Plus – 

mechanical evacuation of intraluminal contents

Treatment recommended for ALL patients in selected patient group

Evacuation using a nasogastric tube reduces pressure exerted by accumulation of gastric and small bowel contents; removal of fluid rather than air is most likely to be of benefit.

Colonic decompression may have a minor impact on intra-abdominal pressure. Removal of fluid or impacted stool is most likely to be of benefit.

If the response to tube placement is inadequate, the patient may benefit from an enema.

However, pharmacologic treatment with gastro- and coloprokinetic agents to further evacuate the GI lumen is usually considered first, before enema therapy.

Limitation or discontinuation of enteral feeding may also be considered if there is no response to tube placement and drug treatment.

Colonoscopic decompression is a final option.

Consider – pharmacologic evacuation of intraluminal contents

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ACUTE
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all patients
Consider – 

pharmacologic evacuation of intraluminal contents

Treatment recommended for SOME patients in selected patient group

Gastro- and coloprokinetic agents are usually considered if placement of nasogastric and rectal tubing is inadequate, especially if ileus is the underlying cause.

Primary options

erythromycin base: 250 mg intravenously every 6 hours

OR

neostigmine: 0.5 mg intramuscularly three times daily

Consider – mechanical ventilation ± vasopressors

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ACUTE
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all patients
Consider – 

mechanical ventilation ± vasopressors

Treatment recommended for SOME patients in selected patient group

Some patients require mechanical ventilation to overcome the effects of pressure transmission from the abdomen to the thorax.

Abdominal perfusion pressure should be maintained at 60 mmHg or greater, which may require use of vasopressors.

Consult specialist for guidance on choice of vasopressor and dose.

Primary options

vasopressin: consult specialist for guidance on dose

OR

norepinephrine: consult specialist for guidance on dose

Plus – percutaneous abdominal decompression

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ACUTE
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all patients
|
no response to initial treatment
Plus – 

percutaneous abdominal decompression

Treatment recommended for ALL patients in selected patient group

Paracentesis with percutaneous decompression should be attempted first. Peritoneal lavage or dialysis catheter is placed percutaneously into the peritoneal cavity and set to gravity drainage. If free fluid volumes are large, intra-abdominal pressure (IAP) is quickly lowered. Successful percutaneous decompression has been associated with fluid drainage of >1000 mL or a decrease in IAP of >9 mmHg in the first 4 hours post decompression.[38]

If ACS persists after percutaneous drainage, surgical treatment should be given immediately.[39] A delay to definitive treatment with surgical decompression often increases the risk of mortality.[24]

Consider – surgical abdominal decompression

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ACUTE
|
all patients
|
no response to initial treatment
Consider – 

surgical abdominal decompression

Treatment recommended for SOME patients in selected patient group

Surgical decompression via a laparotomy is the definitive treatment but is reserved for patients in whom other interventions have failed.[10][40][41] Although general anesthesia is required, the procedure can be safely performed at the bedside in the ICU.[39] This is an important advantage, because many patients with ACS are clinically unstable. It is accomplished by performing a midline laparotomy incision. In most cases both the fascia and the skin are left open and a dressing must be applied to prevent dessication of the viscera.[43][44][45] Patients undergoing decompressive laparotomy will later require permanent abdominal wound closure. Options include delayed primary fascial closure, various flap/fascial release measures,[46][47] mobilization of skin flaps or split-thickness skin grafting, and use of negative pressure wound therapy devices.[49][50] Many patients develop a ventral hernia that requires separate, late management.[48]

Consider – neuromuscular blockade + mechanical ventilation

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ACUTE
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all patients
|
no response to initial treatment
Consider – 

neuromuscular blockade + mechanical ventilation

Treatment recommended for SOME patients in selected patient group

Given as a last resort to patients to decrease compliance of the abdominal wall. Patients require airway control and mechanical ventilation.

Sedative and neuromuscular blocking agents (e.g., pancuronium) may decrease BP and/or cardiac output, which may be problematic in hypotensive patients who remain in shock.

It is important to monitor the adequacy of neuromuscular blockade, especially if intra-abdominal pressure increases while patients are receiving this treatment.[51][52]

Consult specialist for advice on choice of agent and dose.

Consider – dialysis

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ACUTE
|
all patients
|
no response to initial treatment
Consider – 

dialysis

Treatment recommended for SOME patients in selected patient group

Dialysis or hemofiltration may effectively mobilize excess fluid, and both are particularly useful in the setting of acute or chronic renal failure, when diuretic therapy is not feasible.

Takes hours to days to be effective, but under some circumstances net removal of even 1 to 2 liters of excess fluid can significantly lower intra-abdominal pressure.

Trained personnel and specialized equipment, while widely available, may not be immediately accessible in all ICUs.

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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