- Definition in surgical context
- In laparoscopic surgery, pneumoperitoneum is deliberately created by insufflating gas (usually CO₂) into the peritoneal cavity to allow working space and visibility
- Typical intra-abdominal pressure (IAP) used: 12–15 mmHg
- Pathophysiological effects of surgical pneumoperitoneum
- Respiratory system
- ↑ IAP elevates the diaphragm → ↓ functional residual capacity (FRC) and lung compliance
- ↑ peak airway pressures
- V/Q mismatch may develop → mild hypoxaemia
- CO₂ insufflation → ↑ CO₂ absorption → hypercapnia → respiratory acidosis if ventilation not adjusted
- Cardiovascular system
- ↑ IAP compresses IVC → ↓ venous return → ↓ preload
- Reflex ↑ SVR and MAP (initially), but excessive pressure (>15 mmHg) can reduce cardiac output
- Renal system
- ↓ renal blood flow due to ↓ cardiac output and direct renal vein compression
- ↓ glomerular filtration rate (GFR) → ↓ urine output
- Splanchnic circulation and GI
- ↓ portal venous flow and mesenteric perfusion with higher IAP
- Potential for bowel wall oedema and impaired motility
- Cerebral and ocular
- ↑ CO₂ → cerebral vasodilation → ↑ intracranial pressure (ICP)
- Venous thromboembolism risk
- Pneumoperitoneum and patient positioning (e.g. reverse Trendelenburg) can reduce venous return from lower limbs → ↑ stasis and thrombosis risk
- Gas embolism (rare)
- Accidental intravascular CO₂ insufflation can cause embolism → cardiovascular collapse