⚠️ Chapter 80: Abdominal Compartment Syndrome (ACS)

IAP >10 mmHg + Organ Dysfunction · Intravesical Pressure · Medical Management · Surgical Decompression · APP

⚠️ Abdominal Compartment Syndrome: Sustained IAP >10 mmHg with Organ Dysfunction

📊 Definitions (WSACS 2013)
• IAP (intra-abdominal pressure): normal 0-7 mmHg in children
• IAH (intra-abdominal hypertension): IAP >10 mmHg in children
• ACS: sustained IAP >10 mmHg + new/progressive organ dysfunction
• APP (abdominal perfusion pressure) = MAP - IAP (target >35-50 mmHg)
📋 IAH Grading (Paediatric)
Grade I: 10-15 mmHg
Grade II: 16-20 mmHg
Grade III: 20-25 mmHg
Grade IV: >25 mmHg
Higher grades → increased mortality
🩸 Pathophysiology — Multi-Organ Effects
• Respiratory: diaphragm elevation → ↓compliance, hypoxia, hypercapnia
• Cardiovascular: ↓preload (IVC compression), ↓contractility, ↑afterload → ↓CO
• Renal: direct compression, ↓GFR → oliguria, AKI
• Abdominal: gut ischaemia, bacterial translocation
• CNS: ↑ICP (impaired venous return)
📋 Risk Factors
• Medical: massive fluid resuscitation, sepsis, burns, pancreatitis, ascites, PEEP >10
• Surgical: post-laparotomy, abdominal surgery, trauma, hernia repair, liver transplant
📏 IAP Measurement (Gold Standard)
• Intravesical (bladder) pressure
• Supine, end-expiration, zero at mid-axillary line
• Instil 1 mL/kg saline (max 25 mL) into bladder
• Complications: urinary tract infection, bladder trauma
⚙️ Management (Stepwise)
1. Medical (non-operative): NG/rectal decompression, sedation/paralysis, diuresis/CRRT, avoid fluid overload, colloids
2. Percutaneous drainage (ascites)
3. Surgical decompression (laparotomy + temporary closure) — life-saving
⚠️ Critical Pearls: IAP >10 mmHg in children is abnormal. ACS untreated has 100% mortality. APP = MAP - IAP, target >35 mmHg in infants, >50 mmHg in children. Decompressive laparotomy is life-saving.

🩺 Step-by-Step: Abdominal Compartment Syndrome Management

1
Identify at-risk patients
Massive fluid resuscitation (>60 mL/kg), sepsis, burns, pancreatitis, abdominal surgery, trauma. High PEEP, liver transplant.
2
Measure IAP (intravesical pressure)
Indicated for any patient with risk factors + abdominal distension, oliguria, respiratory failure, hypotension. Measure q4-6h.
3
Calculate APP = MAP - IAP
Target APP >35 mmHg (infants) to >50 mmHg (children). Low APP indicates inadequate abdominal perfusion.
4
Medical management (IAP 10-20 mmHg)
• NG tube to decompress stomach
• Rectal tube/enemas
• Sedation + neuromuscular blockade (reduces abdominal wall tone)
• Avoid fluid overload → use colloids, diuretics (furosemide), CRRT
• Elevate head of bed (monitor for ↑IAP)
5
Percutaneous drainage (IAP 20-25 mmHg with ascites)
US-guided paracentesis or peritoneal dialysis catheter placement. Less invasive than laparotomy.
6
Surgical decompression (IAP >25 mmHg with organ dysfunction refractory to medical therapy)
Emergency decompressive laparotomy. Leave abdomen open with temporary closure (Bogota bag, vacuum-assisted closure). Definitive closure when IAP normalises.
7
Post-decompression care
Monitor for reperfusion syndrome (acidosis, hyperkalaemia). Continue medical therapy to prevent recurrence.