🔵 Ascites – Implications for Anesthesia


✅ Definition

Ascites is the pathological accumulation of fluid within the peritoneal cavity, most commonly due to portal hypertensionin cirrhosis, but also seen in malignancy, heart failure, nephrotic syndrome, and TB.


✅ Physiological & Pathophysiological Effects Relevant to Anesthesia

System

Implications

Respiratory

↓ Functional residual capacity (FRC), ↑ risk of hypoxia, basal lung atelectasis, difficult ventilation, ↑ aspiration risk.

Cardiovascular

↑ Intra-abdominal pressure (IAP) → ↓ venous return, impaired preload, possible compression of IVC. May mask hypovolemia.

Gastrointestinal

↑ Risk of aspiration due to increased gastric pressure, delayed gastric emptying, GERD.

Renal

Often coexists with hepatorenal syndrome or prerenal azotemia. Sensitive to changes in volume and perfusion.

Hematologic

Often associated with coagulopathy and thrombocytopenia in liver disease.

Airway

Positioning issues and reduced diaphragmatic excursion may worsen ventilation in supine position.



✅ Preoperative Considerations

  1. Thorough Evaluation
    • Determine cause of ascites (cirrhosis vs malignancy vs heart failure).
    • Assess severity: Abdominal girth, tense vs moderate ascites.
  1. Investigations
    • LFTs, INR, platelet count, renal function, electrolytes (especially sodium), ABG.
    • Chest X-ray: Elevated hemidiaphragms.
    • Echocardiography if cardiac involvement suspected.
  1. Optimization
    • Therapeutic paracentesis: Especially if tense ascites. Reduces IAP, improves ventilation and cardiac output.
    • Albumin replacement (6–8 g/L fluid removed) to prevent paracentesis-induced circulatory dysfunction.
    • Correct coagulopathy if needed before invasive procedures.
  1. Aspiration prophylaxis
    • H2 blockers or PPIs.
    • Prokinetics (e.g., metoclopramide).
    • Rapid Sequence Induction (RSI) if GA needed.


✅ Intraoperative Considerations

Parameter

Consideration

Positioning

Head-up or semi-Fowler’s position improves respiratory compliance.

Airway

RSI is recommended due to high aspiration risk.

Ventilation

May require higher airway pressures due to reduced compliance. Watch for barotrauma.

Monitoring

Consider invasive arterial pressure monitoring, CVP/TEE if major surgery.

Circulation

Be prepared for hypotension after induction. Volume status must be carefully managed.

Drugs

Altered pharmacokinetics in liver disease: avoid hepatotoxic drugs.

Fluid Management

Maintain adequate preload; be cautious with fluid overload. Albumin may be preferred.



✅ Regional Anesthesia Considerations

  • Low threshold for bleeding risk evaluation.
  • Coagulopathy and thrombocytopenia may contraindicate neuraxial blocks.
  • In moderate ascites with acceptable coagulation, spinal anesthesia can be performed with care.
  • Epidural anesthesia is riskier due to potential for hematoma and unpredictable spread.


✅ Postoperative Considerations

  • Extubation criteria should be strict: FRC is low, and risk of respiratory decompensation is high.
  • Monitor for hypotension, renal dysfunction.
  • Careful analgesia planning: Avoid NSAIDs; use opioids cautiously.
  • Avoid fluid overload – ascitic patients are prone to third-spacing and pulmonary edema.


🔶 Key Points for Viva/MCQ

  • Tense ascites → paracentesis before GA.
  • Albumin given after paracentesis to prevent circulatory dysfunction.
  • Ascites increases aspiration risk → RSI needed.
  • FRC reduced → early desaturation.
  • Spinal anesthesia is not contraindicated per se but must be approached cautiously if coagulopathy exists.