First Things First (assess & treat for the following)

• Recognize who is at risk
  • Patients after trauma with massive resuscitation or contamination, AAA repair, liver transplant, hepatic failure with ascites, retroperitoneal bleed, massive resuscitation after sepsis or burns, pancreatitis, bowel obstruction, intra-abdominal sepsis (diverticulitis, perforated ulcer, appendicitis), or ARDS.
• Correct what can be corrected
  • Ongoing bleeding
    • Surgery or interventional radiology
    • Coagulopathy
  • Intra-abdominal sepsis
    • Drainage (open versus percutaneous)
    • Bowel resection
  • Decompress bowel if obstructed
    • NGT
    • Enemas
    • Prokinetic agents

History and Physical (assess for the following)

• Assume in anyone with systemic signs of hypoperfusion and abdominal distention.
• Affects all organ systems
  • Neuro
    • Increased ICP
  • Cardiovascular
    • Increased heart rate
    • Decreased BP
    • Decreased cardiac output (CO)
    • These are from decreased venous return
  • Pulmonary
    • Decreased FRC
    • Increased hypoxia
    • Worsening compliance
    • Increased pCO2
    • Increased plateau/peak airway pressures
  • Hepatic/Intestines
    • Decreased visceral perfusion and portal venous flow
    • Lactic acidosis
    • Bacterial translocation
    • Worsening coagulopathy due to decreased synthesis
  • Renal
    • Decreased GFR due to lack of blood flow
    • Decreased urine output
  • Skin and soft tissue
    • Decreased fascial blood flow
    • Decreased capillary refill
    • Can contribute to wound infections or dehiscence

Diagnosis

• Have low index of suspicion in patients developing signs of hypoperfusion.

• • Once suspected, measure bladder pressure.
    • Clamp Foley distally (towards collection bag).
    • Instill 25 mL saline into Foley catheter.
    • Measure with manometer or place pressure transducer to sampling port.
    • Pubic symphysis is reference point.

• • Intra-abdominal hypertension (IAH) = sustained intra-abdominal pressure >12 mmHg
    • 12-15 mmHg = Grade I IAH
    • 16-20 mmHg = Grade II IAH
    • 21-25 mmHg = Grade III IAH
    • >25 mmHg = Grade IV IAH

• • Abdominal compartment syndrome is IAH >20 mmHg plus end-organ dysfunction. It is not graded but is an all-or-nothing diagnosis.
    • Primary - occurs due to abdominal/pelvic process - bleed from trauma or ruptured vessel, liver transplant, retroperitoneal hemorrhage, or intra-abdominal sepsis
    • Secondary - occurs from resuscitation for an extra-abdominal process such as burns, sepsis, or ARDS
    • Recurrent - occurs after treatment of primary or secondary ACS following closure of decompressive laparotomy
  • Also monitor other measures of end-organ hypoperfusion
    • Creatinine
    • Base deficit
    • Lactate
    • Liver enzymes
    • CPK
    • ABGs
    • PT/PTT/INR
    • Urine output

General Management Principles

• As with most ICU emergencies, IAH/ACS management centers around early diagnosis, correction of treatable conditions, and frequent re-assessment.

Specific Treatment

• Intra-abdominal hypertension (bladder pressure >12 mmHg)
  • Improve abdominal wall compliance
    • Sedation and analgesia
    • Reverse Trendelenburg
    • Neuromuscular blockade
  • Minimize intra-abdominal volume
    • Bowel decompression with NGT and/or enemas
    • Paracentesis
    • GI prokinetics (metoclopramide, erythromycin, neostigmine)
  • Correct positive fluid balance
    • Avoid over-resuscitation
    • Diuretics (if blood pressure allows)
    • Hypertonic saline
    • Hemofiltration if oliguric
• Abdominal compartment syndrome (IAH >20 mmHg + end-organ dysfunction)
  • Decompressive laparotomy
    • Consider early to improve outcome and rates of closure

Ongoing Assessment

• Monitor bladder pressure until < 12 mmHg
• Monitor end-organ function
  • Creatinine
  • Base deficit
  • Lactate
  • Liver enzymes
  • CPK
  • ABGs

Complications

• If untreated or delay in diagnosis
  • Renal failure
  • Hypoxia
  • Hypercapnea
  • Visceral ischemia
  • Rhabdomyolysis
• Related to therapy
  • Hernia
  • Enterocutaneous fistula

Author

• Jason S. Lees, MD