General Abdomen: Abdominal Compartment Syndrome
Abdominal Compartment Syndrome (ACS)
Definition
- Intraabdominal Hypertension – Sustained Intraabdominal Pressure ≥ 12 mmHg
- Abdominal Compartment Syndrome – Sustained Intraabdominal Pressure ≥ 20 mmHg & Associated with New Organ Dysfunction
- Primary ACS – Originates from Injury or Disease in the Abdomen/Pelvis
- Secondary ACS – Originates from Injury or Disease Outside of the Abdomen/Pelvis
Pathophysiology
- Intraabdominal Hypertension Causing Organ Dysfunction
- CV: Decreased Cardiac Output
- Cause: IVC Compression > Low Venous Return > Decreased Preload
- Pulm: Increased Airway Pressure & Decreased Compliance
- Cause: Diaphragm Displaced Upward > Extrinsic Compression
- Renal: Renal Impairment & Oliguria
- Cause: Poor Perfusion (Low CO), Renal Venous Resistance & Shunting of Blood from Cortex to Medulla
- GI: Mucosal Ischemia & Perforation
- Cause: Reduced Mesenteric Blood Flow
Causes
- Primary ACS
- Trauma (Most Common)
- Abdominal Surgery
- Liver Transplant
- Massive Ascites
- Ruptured AAA
- Pancreatitis
- Secondary ACS
- Severe Burns
- Massive IVF Resuscitation
- Sepsis
Presentation
- Fatigue
- Dyspnea
- Abdominal Pain & Distention
- Oliguria
Intraabdominal Hypertension Grading
- Grade I: 12-15 mmHg
- Grade II: 16-20 mmHg
- Grade III: 21-25 mmHg
- Grade IV: > 25 mmHg
Diagnosis
- Primary Dx: Bladder Pressure > 20 mmHg
- Measured at End-Expiration
- May Be Inaccurate if Not Supine & Sedated
- Normal Intraabdominal Pressure: 5-7 mmHg
- Chronically Higher in Pregnant, Ascites & Obese (10-15 mmHg)
Treatment
- Definitive Treatment: Decompressive Laparotomy
- Temporize: Supine Position, Sedation/Paralytics, NGT Decompression, Low Tidal Volume & High PEEP
- If Obvious Intraperitoneal Fluid – Paracentesis May Prevent Laparotomy
- Complications of Decompression:
- Respiratory Alkalosis
- Decrease in Preload (Induce Hypotension)
- Bolus of Acid, K & Other Anaerobic Byproducts (Induce Arrhythmia)