Anaesthesia for Liver Resection

An overview of the process

The liver bleeds from its veins, not from its arteries. The sinusoids on the cut surface communicate directly with the hepatic veins and the inferior vena cava, so it is venous pressure rather than arterial pressure that determines how much the transection surface bleeds. Venous pressure = blood loss.

The operation has two haemodynamic phases requiring opposite management: a deliberately dry phase during parenchymal transection, and a filling phase once haemostasis is achieved.

Most resections are for colorectal liver metastases, hepatocellular carcinoma, or lesions previously treated with selective internal radiation therapy. Blood loss is usually modest, but major haemorrhage can occur — plan for it.

Pre-op assessment

• Establish from the surgical team how much liver is being removed, whether the remnant is normal or chemotherapy-injured, steatotic or cholestatic, and whether portal vein embolisation has been performed to grow the remnant. A right hemihepatectomy in an injured liver is a different operation from a wedge in a normal one, and the difference shows in the postoperative course rather than in theatre.
• Take a chemotherapy history specifically. It informs both the patient's reserve and the quality of the liver being left behind.
• Exercise tolerance in METs remains a very useful single item in the history.
• Bloods: FBC, U&E, LFTs and clotting — an epidural is likely, and hepatic synthetic function may already be impaired.
• In a cholestatic patient, establish the bilirubin trend and whether biliary drainage has been performed. Drainage is recommended for a cholestatic liver, and surgery should ideally wait until the bilirubin is below 50 µmol/L.
• Smoking cessation should be counselled at least 4 weeks before hepatectomy. For heavy drinkers, alcohol cessation 4–8 weeks beforehand.
• Nutritional assessment is required before all hepatic surgery. Malnourished patients should be optimised with enteral supplementation for 7–14 days preoperatively.
• Confirm a valid crossmatch, and that blood is physically available, before the list starts rather than when the surgeon reaches the cava.
• Consent covers general anaesthesia, thoracic epidural, arterial line, central line, the real possibility of significant blood loss and transfusion, and a bed on HDU.

Induction and intra-operative management

• For open resection: thoracic epidural sited at approximately T6–7 and tested before induction. Maintenance with volatile; there is no strong evidence favouring volatile over TIVA or the reverse.
• For laparoscopic resection: spinal with morphine, TIVA/volatile, with ETT for the airway.
• An arterial line is required.
• Central venous access should be established before transection begins, as the CVP is being used as a target rather than for monitoring alone.
• Large-bore peripheral cannulae / HF CVL.
• Maintain full neuromuscular blockade throughout with train-of-four monitoring. Surgical access is deep beneath the diaphragm and any tone works against it.
• Active warming from the start, with forced-air warming and a fluid warmer. Hypothermia, dilution and impaired hepatic synthesis combine to produce a coagulopathy that is difficult to reverse.
• A urinary catheter is required. Mechanical thromboprophylaxis should be used if not contraindicated.
• Single-dose antibiotic prophylaxis within 60 minutes of incision, redosed if the operation is prolonged.
• During mobilisation the liver is lifted and rotated off the cava, producing sudden and sometimes profound hypotension from caval compression. This is mechanical, resolves as soon as the retractor moves, and should not be treated with fluid.
• Air embolism is a recognised risk when hepatic veins are open at low venous pressure. Sudden desaturation with a falling end-tidal CO₂ and cardiovascular collapse during transection should be treated as air until proven otherwise: flood the field with saline and position the patient head-down.

Fluid management and the low central venous pressure technique

• Target a CVP below 5 cmH₂O during parenchymal transection.
• This is achieved by restricting fluid during transection and by using a vasopressor, rather than volume, to maintain arterial pressure.
• Low CVP anaesthesia reduces blood loss and transfusion requirement.
• The technique requires end-organ perfusion to be maintained at the same time. Follow urine output and serial lactate. Concerns that vasoconstrictors cause splanchnic hypoperfusion, or that low CVP causes renal impairment, are not supported by current evidence — but a low CVP target is not a reason to tolerate an unsafe arterial pressure, and a target that cannot be delivered safely should be discussed with the surgeon.
• Balanced crystalloid is preferred to 0.9% saline or to colloid.
• Once the specimen is out and haemostasis is achieved, reverse the strategy and fill; patients otherwise reach recovery underfilled, oliguric and acidotic.
• A restrictive transfusion approach is appropriate. Follow haemoglobin on serial gases and keep a running total of losses that both surgeon and anaesthetist can see.

The Pringle manoeuvre

• Intermittent clamping of the hepatoduodenal ligament occludes portal venous and hepatic arterial inflow during transection.
• On clamping, venous return falls and systemic vascular resistance rises. Arterial pressure usually rises, and a normal rise requires no treatment.
• On release, arterial pressure falls and there is a washout of lactate and potassium from the ischaemic remnant. Anticipate this rather than react to it; keep vasopressor available and check a gas with a potassium after prolonged clamping.
• Ask the surgeon to call clamp on and clamp off, and record the times. Cumulative ischaemic time is relevant to the function of the remnant.

Perioperative analgesia

• Regular paracetamol.
• Thoracic epidural provides good analgesia for open resection but carries real disadvantages: hypotension is harder to manage alongside a deliberately low CVP, and impaired postoperative synthetic function complicates catheter removal. Continuous wound infiltration and TAP blockade are alternatives.
• For laparoscopic resection, intrathecal morphine is a recognised approach.
• PONV prophylaxis with at least two agents — dexamethasone at induction and ondansetron at the end of surgery is the usual pairing.
• Thromboprophylaxis after hepatectomy is generally started postoperatively rather than preoperatively. For prophylactic low molecular weight heparin, allow 12 hours from the last dose before siting or removing an epidural catheter and 4 hours afterwards; for treatment dose, 24 hours and 4 hours. Extend the interval if insertion was traumatic.
• Hepatic synthetic function falls for the first two to three days, so the INR commonly rises postoperatively while the epidural catheter is still in situ. Check clotting before the catheter is removed and state this explicitly in the handover.

Post-operative care

• Patients are anticipated to go to HDU following major resection.
• Handover should include the segments resected, the Pringle clamp times, the blood loss, whether filling has been completed since haemostasis, the current vasopressor, the epidural settings, dose of low molecular weight heparin and when the next is due, and the last gas.
• Post-hepatectomy liver failure is the principal cause of death after liver resection and declares itself late — bilirubin and INR still rising beyond day 5, persistent lactataemia, new confusion. It is graded by the ISGLS definition, and the "50-50 criteria" (abnormal prothrombin time and bilirubin on day 5) allow early detection.
• Hypoglycaemia should be actively excluded after major resection. Gluconeogenic capacity is reduced and the abnormality runs opposite to the hyperglycaemia expected after most major abdominal surgery, so it is easily missed. Measure the glucose.
• Maintain normoglycaemia with insulin, targeting a blood glucose below 8.3 mmol/L.
• Other complications to anticipate are bleeding, bile leak, acute kidney injury and chest sepsis.
• Early oral intake and mobilisation from the day of surgery.

References

1. Joliat GR, Kobayashi K, Hasegawa K, et al. Guidelines for Perioperative Care for Liver Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations 2022. World Journal of Surgery, 2023.
2. Perioperative management for hepatic resection surgery. BJA Education, 2022.
3. Anaesthesia for hepatic resection surgery. Continuing Education in Anaesthesia, Critical Care and Pain.
4. Rahbari NN, Garden OJ, Padbury R, et al. Posthepatectomy liver failure: a definition and grading by the International Study Group of Liver Surgery (ISGLS). Surgery, 2011.
5. Association of Anaesthetists of Great Britain & Ireland, Obstetric Anaesthetists' Association, Regional Anaesthesia UK. Regional anaesthesia and patients with abnormalities of coagulation.
6. Kietaibl S, Ferrandis R, Godier A, et al. Regional anaesthesia in patients on antithrombotic drugs: Joint ESAIC/ESRA guidelines. European Journal of Anaesthesiology, 2022;39:100–132.