Increased Retroperitoneal Volume

• Acute Pancreatitis (see Acute Pancreatitis, [[Acute Pancreatitis]]): edema from inflammation and large volume IVF resuscitation
• Retroperitoneal Hemorrhage (see Retroperitoneal Hemorrhage, [[Retroperitoneal Hemorrhage]]): due to penetrating/blunt trauma, aortic surgery, ruptured AAA

Increased Intraperitoneal Volume

• Abdominal Neoplasm
  • Ovarian Cancer with Bulky Masses (see Ovarian Cancer, [[Ovarian Cancer]])
• Bowel Distention
  • Severe Bowel Ischemia (see Acute Mesenteric Ischemia, [[Acute Mesenteric Ischemia]])
  • Small Bowel Obstruction (SBO) (see Small Bowel Obstruction, [[Small Bowel Obstruction]])
• Hemoperitoneum (see Hemoperitoneum, [[Hemoperitoneum]]): associated with penetrating/blunt trauma
• Massive Splenomegaly (see Splenomegaly, [[Splenomegaly]])
  • Epidemiology: massive splenomegaly with abdominal compartment syndrome has been reported in association with myelofibrosis (Am J Hematol, 2005) [MEDLINE]
• Mesenteric Venous Obstruction (see Mesenteric Vein Thrombosis, [[Mesenteric Vein Thrombosis]])
  • Epidemiology: xxx
• Pneumoperitoneum (see Pneumoperitoneum, [[Pneumoperitoneum]])
• Post-Liver Transplant (see Liver Transplant, [[Liver Transplant]])
• Pregnancy (see Pregnancy, [[Pregnancy]])
• Tense Ascites (see Ascites, [[Ascites]])

Extrinsic Compression of the Abdomen

• Abdominal Wall Burn Eschar (see Burns, [[Burns]])
• Tight Abdominal Closure After Surgery

Acute Increase in Intra-Abdominal Pressure

• Transmission of Intra-Abdominal Pressure to the Thorax
  • Studies Indicate that Approximately Half of the Intra-Abdominal Pressure is Transmitted to the Plateau Pressure on the Ventilator (J Trauma Acute Care Surg, 2013) [MEDLINE]: therefore, the plateau pressure should be corrected down for this effect in the setting of abdominal compartment syndrome, to give a “true” plateau pressure
    • Note: pressure measurements require conversion of abdominal pressure (in mm Hg) to plateau pressure (in cm H20): 1 cm H20 = 0.736 mm Hg
    • Example: intra-abdominal pressure of 25 mm Hg = 33.97 cm H20
  • Measuring Esophageal Pressure May Be Used as a Surrogate for Pleural Pressure (NEJM, 2008) [MEDLINE]: this may facilitate higher levels of PEEP, if required for oxygenation
    • Trans-Pulmonary Distending Pressure = Plateau Pressure – Esophageal Pressure

Cardiovascular Manifestations

Hypotension/Cardiogenic Shock (see Hypotension, [[Hypotension]] and Cardiogenic Shock, [[Cardiogenic Shock]])

• Physiology: increased intra-abdominal pressure, which is transmitted to the thorax -> decreased cardiac filling (decreased preload) and increased afterload
• Diagnosis
  • Central Venous Pressure (CVP): increased (without increased right end-diastolic volume) -> may lead to spurious interpretation of CVP measurements
  • Pulmonary Capillary Wedge Pressure (PCWP): increased (without increased left end-diastolic volume) -> may lead to spurious interpretation of PCWP measurements
  • Cardiac Output (CO): decreased
  • Systemic Vascular Resistance (SVR): increased
• Treatment: intravenous fluid administration administration may worsen bowel wall edema -> exacerbating abdominal compartment syndrome

Pulsus Paradoxus (see Pulsus Paradoxus, [[Pulsus Paradoxus]])

• Physiology: due to transmission of high intra-abdominal pressures to thorax -> impaired right-sided venous return

Pulmonary Manifestations

Hypoxemia (see Hypoxemia, [[Hypoxemia]])

• Physiology decreased FRC and V/Q mismatch

Acute Respiratory Failure (see Respiratory Failure, [[Respiratory Failure]])

• Physiology: increased intra-abdominal pressure -> decreased chest wall compliance and excessive work of breathing
• Diagnosis
  • Increased PIP and Plateau Pressure on Ventilator

Renal Manifestations

Acute Kidney Injury (see Acute Kidney Injury, [[Acute Kidney Injury]])

• Physiology
  • Kidneys are Early Sensors for the Presence of Abdominal Compartment Syndrome
  • Increases in Abdominal Pressure as Low as 12 mm Hg May be Associated with AKI (Acta Clin Belg, 2007) [MEDLINE]
  • Sustained Intra-Abdominal Pressure >20 mm Hg in Association with New Organ Dysfunction are Associated with AKI in >30% of Cases (Arch Surg, 1999) [MEDLINE] (Intensive Care Med, 2007) [MEDLINE]

Multiple Compartment Syndrome

• Epidemiology: occurs in setting of multiple trauma
• Physiology
  • Intravenous fluid administration and acute lung injury increase intra-abdominal and intrathoracic pressures -> these lead to increased intracranial pressure after traumatic brain injury
  • Additional IVF administered to maintain cerebral perfusion or increased ventilatory support to treat acute lung injury further raise the intracranial pressure
  • These mechanisms can result in a cycle that culminates in multiple compartment syndrome
• Treatment
  • Decompressive Craniectomy (see Decompressive Craniectomy, [[Decompressive Craniectomy]]): lowers intracranial pressure [MEDLINE]
  • Decompressive Laparotomy: lowers intra-abdominal pressure and intracranial pressure [MEDLINE]

Supine Position

• Rationale: avoid elevation of head of bed and proning, as both increase intra-abdominal pressure

Ventilator Management

• Decrease Tidal Volume (VT): instituting a decrease in tidal volume has traditionally been recommended to decrease extrinsic pressure on the abdominal compartment
  • However, Studies Indicate that Approximately Half of the Intra-Abdominal Pressure is Transmitted to the Plateau Pressure on the Ventilator (J Trauma Acute Care Surg, 2013) [MEDLINE]: therefore, the plateau pressure should be corrected down for this effect in the setting of abdominal compartment syndrome, to give a “true” plateau pressure
    • Note: pressure measurements require conversion of abdominal pressure (in mm Hg) to plateau pressure (in cm H20): 1 cm H20 = 0.736 mm Hg
    • Example: intra-abdominal pressure of 25 mm Hg = 33.97 cm H20
  • Consequently, if the Corrected Plateau Pressure is Acceptable, a Decrease in Tidal Volume May Not Be Warranted: this is especially true in a patient with severe metabolic acidosis and inability to compensate with current mechanical ventilation settings, where decreasing the tidal volume may worsen the compensation for acidosis

Sedation with Neuromuscular Blockade

• Rationale: both may reduce intra-abdominal pressure in patients who are dyssynchronous with the ventilator

Prokinetic Agents

• Rationale: may be useful in patients with severe ileus

Surgical Decompression

• Bogota Bag: plastic bag over opened abdominal wall
• Definitive Closure: can usually be performed within 48 hrs