Haemodynamic management
In addition to standard anaesthesia monitoring (ECG, pulse oximetry, temperature monitoring, relaxometry, bladder catheter), haemodynamic monitoring should include the insertion of an arterial catheter to continuously measure arterial blood pressure, and a central venous catheter (CVC) to measure central venous pressure (CVP). The insertion of transesophageal echocardiography (TEE) may be of concern in patients with oesophageal varices, even though it may be beneficial for haemodynamic and volume monitoring.
The insertion of a pulmonary arterial catheter (PAC) can be considered in patients with decreased cardiac function. Alternatively, the application of a continuous haemodynamic monitoring system (e.g. PICCO™, Pulsion Medical Systems, Munich, Germany) could be indicated.
Given the potential for massive haemorrhage during hepatic preparation and resection, the insertion of large-bore venous catheters is mandatory. In our institution, we normally place a four-lumen CVC and second large-bore CVC with a port for a pulmonary arterial catheter. In patients with decreased renal function, an additional Quinton catheter for eventual postoperative hemofiltration may be useful.
Volume management
The amount of blood transfusions correlates directly with postoperative complications and mortality [
45]. Therefore, both surgical as well as anaesthesiologic management should aim do minimise blood loss.
The two major reasons for bleeding in liver resections are surgical lesions in extrahepatic liver veins and bleeding due to parenchyma transection. Blood pressure in hepatic sinusoids depends on hepatic venous pressure, which also correlates with CVP.
Lowering CVP is a simple but effective method to reduce blood loss during liver resections [
46,
47]. Although the value and necessity of low CVP is still discussed, we aim for a low CVP during preparation and resection to reduce blood loss and facilitate surgical handling.
Minimizing intravenous volume infusion is also an effective tool to decrease CVP. If this is not sufficient, intravenous use of nitro glycerine can be used in order to reduce CVP. Volume and blood loss must be monitored and corrected continuously. Vasopressor therapy is often necessary to maintain adequate blood pressure levels. Lowering PEEP during resection to an acceptable minimum (i.e. 5 cmH2O) can help to reduce CVP. According to the literature, low CVP-assisted liver resections do not lead to an increase in acute kidney injury (AKI) [
48].
Volume status needs to be evaluated repeatedly, because hypovolaemia can mediate organ dysfunction trough impaired systemic tissue perfusion. But one has to be careful, because hypervolemia increases oedema formation [
49].
Urine output must be monitored continuously as an intraoperative oliguria <0.3 ml/kg/h is associated with an increased risk of postoperative AKI [
50].
For fluid replacement we use colloids (Gelofusin™, B. Braun Melsungen AG, Melsungen, Germany) and balanced crystalloid fluids in our hospital.
Depending on blood loss and coagulation tests (TEG), we use fresh frozen plasma and coagulation factors for coagulation therapy. The use of antifibrinolytic agents (tranexamic acid) is indicated in operations with major blood loss or signs of hyperfibrinolysis in the TEG.
Given the negative impact of hypothermia on coagulation, it is crucial to monitor and control the patient’s temperature. Normothermia should be maintained by using extern-warming systems (e.g. Bair Hugger™, 3M, St. Paul, United States).