1. DR. ANUPRIYA GARG
UNDERGUIDANCE OF DR. AKANKSHA DUTT

2. Introduction
The liver is most unusual in that it can regenerate functionally
active tissue. Therefore, much of the liver can be removed, followed
by regeneration.
The liver consists largely of hepatocytes, which are
unipotent cells, in that they have the capacity to develop or
differentiate into only one type of cell.
 Although there is a return to the original liver mass, the
shape of the regenerated liver is not fully restored.
 Non-parenchymal cells such as bile duct, endothelial and Kupffer
cells replicate more slowly.
The liver regenerates rapidly over about 1 month,
but functional capacity is slower to return in the larger resections.
Diabetes and cirrhosis will slow this process considerably, as will
sepsis or any other major perioperative complication.

3. This ability of the liver led to early attempts at hepatic
resection.
However, initially this was fraught with difficulty. In particular
haemorrhage was a major problem, because of the difficulty in
suturing or sealing hepatic tissues.
However, improvements in surgical and anaesthetic techniques
gradually reduced this problem.
Now perioperative mortality has fallen from 20%, forty years
ago, to around 3%.

4. INDICATIONS
The most common indication in the UK is the removal of
hepatic metastases from colorectal carcinoma. Overall five year
survival is 40%, compared to close to zero without hepatic resection.
Liver resection is also important for the removal of primary
hepatic
tumours such as hepatocellular carcinomas or biliary tumours such
as cholangiocarcinomas and occasionally following trauma to the
liver.
It may also be used for removal of benign liver tumours, liver
cysts, although deroofing and drainage may be more appropriate
and for live donor liver transplantation.
Segmental resections may be required as part of
hepaticojejunostomy procedures for high bile duct injuries.

5. Liver anatomy
The liver is highly vascular, receiving a total blood flow of 1.5 litre min,
of which 80% is supplied by the portal vein and 20% from the
hepatic artery.
The liver can be divided into five sectors and further sub-divided into
eight functional segments ,described by their blood supply and biliary
drainage.
The portal vein divides successively to supply each liver segment,
reflecting similar divisions of the hepatic artery and bile duct.
Segmental portal and hepatic arterial blood supply and biliary drainage
are unique, so contiguous segments can be resected without disrupting
the vascular supply to neighbouring tissue.
There are few bloodless planes of dissection, and functional
divisions are invisible on the surface of the liver

6. Preoperative assessment
This combines the impact of a large upper
abdominal wound with surgery to the liver. The larger the liver
resection more traumatic the surgery
a greater potential for blood loss, lengthy clamp times and more
chances of liver failure.
This can be further complicated if the tumour lies close to
large vessels, resulting in potentially greater loss of vascular supply
to liver tissue. Therefore the nature of the surgery itself is important.
Laparoscopic techniques are improving,but in general are only
suitable for relatively accessible or small lesions or liver cysts.
However, anaesthetists need to be prepared for sudden conversion
to an open technique.

7. Little data exists on precise exercise tolerance for open hepatic
resection, but less than 1 flight of stairs exercise tolerance due to
breathlessness or angina, especially if combined with arrhythmias
such as atrial fibrillation, will produce a high risk of perioperative
mortality or morbidity.
 Low CVP levels are needed to help reduce blood loss. Therefore,
diseases that increase right sided pressures in the heart may well lead
to increased inferior vena caval pressures and so will increase blood
loss. Therefore, valvular lesions, such as pulmonary stenosis may
have so severe an impact on pressure that valve replacement is
required prior to liver surgery.

8. The large abdominal incision increases the risk of postoperative
lung atelectasis, therefore severe chest diseases will have major
impact on outcome.
The presence of other diseases of the liver will also increase risks.
Patients with Child-Pugh scores of B or C should not receive liver
resection surgery because the risk of postoperative
liver failure is very high.
 Clotting should be normal or very close to normal if liver resection is
not going to produce severe deteriorations in prothrombin time.
Platelets may be relatively low due to hypersplenism in patients with
cirrhosis and a cirrhotic liver may be more prone to bleeding because
of the texture of the liver itself and abnormal surrounding vasculature.
 Patients with a severely fatty liver as for example seen in extreme
obesity will also be at greater risk of liver failure.

9. Liver function tests needs to be checked preoperatively.
A low albumin may suggest early liver impairment, therefore
consideration needs to be given to the cause of any abnormality.
Is there a degree of obstruction that can be relieved at the time of the
operation or by stenting or percutaneous radiological techniques or
is their insufficient functioning liver to allow for a safe resection?

10. Risk stratification can be improved by using indocyanine green
(ICG) retention. ICG is rapidly extracted by the liver and is excreted
in the bile unchanged by a first order kinetic process and has been
used to assess graft function in liver transplantation. An indocyanine
green retention rate of 14% or below at 15 min is considered
the safety limit for major hepatectomy for cirrhotic patients, with
a maximum of 60% of non-tumorous tissue being resected.
 ASA grading, age, size of resection, preoperative cholangitis, elevated
creatinine, bilirubin (and pre-existing cirrhosis), especially if followed by
high operative blood loss have been shown to risk factors.

11. Surgical considerations at preoperative assessment will first
establish whether there is disease spread beyond the liver. Single
isolated metastases beyond the liver may be amenable to palliative
surgery, but the overall outcome will be severely downgraded and
so the logic of taking preoperative risks will be reduced.
Surgical assessment will also consider the involvement of major blood
levels in the metastases and whether surgery is feasible without
Sacrificing too much of the liver blood supply, hence increasing the
percentage of liver that needs to be removed.
At most, 80% of the liver can be removed, but the risks of liver failure
and other complications are high.
If there is doubt a laparoscopic examination can be
performed before more extensive surgery is commenced.

12. Patients may come to theatre following chemotherapy to shrink
metastases, especially if they are close to important vessels. There
have been concerns that chemotherapy might impair regeneration,
especially when the liver has experienced periods of ischaemia.
However, although regeneration may be delayed chemotherapy
does not prevent the use of clamping of the blood supply to the
liver.
Commonly patients will be seen with peripheral neuropathies
after oxaliplatin based chemotherapy. This should be documented
to avoid later confusion with potential adverse effects of
epidural blockade.

13. Clinical & Biochemical POINTS SCORED
variables 1 2 3
Serum albumin (g/L) >35 28-35 <28
Serum bilirubin (µmol/L) <35 35-60 >60
[Mg /dl] < 2 2 -3 >3
PT (seconds) prolonged 1-4 4-10 10
from control INR [ < 1 .7] INR [1.7 - INR >2.3
2.3]
Ascites None Mild Moderate
Encephalopathy Absent Grade I – Grade III – IV
II
POINTS : 5- 6 – class A [5% Mortality] ,
7 -9 –Class B [10% mortality], 10 -15 –Class C [50% mortality]

14. Polycystic disease of the liver and kidneys
Occasionally, huge numbers of liver cysts may form, sometimes
in association with renal polycystic disease.
As well as the risk of renal impairment, the hepatic cysts may
force the diaphragm upwards due to positional effects and
increased intra abdominal pressure, so gradually impairing
respiration .
Following surgery, the diaphragm may still be overstretched and
no longer be able to use the abnormal liver as a fulcrum leading to
increased inefficiency until it is able to remodel itself. Non-invasive
ventilation or even respiratory support via a temporary
tracheostomy may be required until remodelling occurs.

15. Anaesthetic technique
Probably the most common technique is intravenous induction
with propofol, accompanied by a remifentanil infusion, initial
paralysis for intubation with atracurium and maintenance with
a volatile agent such as isoflurane or sevoflurane, which has a low
chance of producing an increase in liver enzymes, whilst adding to
peripheral vasodilatation, which is helpful in attaining a low CVP.
Known hepatotoxins such as halothane should be avoided.
Nitrous oxide should be avoided as it causes gut distension.
During resection PEEP may be reduced to zero to reduce the
intrathoracic pressure, so assisting venous return and lack of back
pressure on the hepatic veins.

16. Usually, a thoracic epidural is inserted at around T8/9 or T9/10
while the patient is awake. A mixture of local anaesthetic such as
bupivacaine and fentanyl is usually used (depending on the centre).
An epidural infusion is then maintained for the next four to five
days. In the postoperative period after large liver resections plain
bupivacaine without fentanyl may become necessary. Some
authorities argue that the risk from epidural analgesia is too great
because of the risk of abnormal coagulation.However, the
evidence for a high rate of complications is lacking.
 Transfusion of fresh frozen plasma may be necessary to cover epidural
removal in the postoperative period.

17. CVP and arterial lines are sited in the anaesthetic room, together
with a urinary catheter with temperature probe attachment.
 In addition to warmed fluids, two air blanket warmers are used to
help maintain normal body temperature in the face of a large
abdominal incision and occasionally large volumes of administration
of intravenous fluids.
Liver resections have been undertaken without utilising epidural
analgesia, by using other regional techniques such as paravertebral
or transversus abdominis plane (TAP) block and by using morphine
based analgesia via PCA. This removes the potential hazard of an
epidural haematoma occurring if clotting problems become excessive.

18. However, analgesia is rarely as effective and is less reliably
prolonged and so the potential for increased incidence of respiratory
failure is present.
In large resections where liver function is reduced, intravenous
analgesia may lead to increased drowsiness, hallucinations,
respiratory depression and failure to cough.
Local anaesthetic toxicity can occur, but is relatively rare.
Antibiotic prophylaxis of cefuroxime or augmentin and
metronidazole is given. Local policies may vary.
In large resections the disruption to Kupffer cells may add to the
importance of prophylaxis.

19. Intraoperative management
In addition to standard monitoring, large bore venous access
should be established, together with central venous pressure (CVP)
and invasive arterial monitoring.
Monitoring cardiac output (and stroke volume variation during
mechanical ventilation) may be helpful. The use of transoesophageal
echocardiography or pulmonary artery flotation catheter has also been
described.
The key is to understand how hypovolaemia is affecting cardiac
output and to anticipate when filling is becoming too low or conversely
too generous. This is because a low CVP will be needed to reduce
bleeding during the resection.
 Commonly, the surgeon will clamp the hepatic artery and
portal veins. The route for blood loss will then be backflow through
the hepatic veins. Therefore, it is important to maintain a low CVP,
ideally not more than 5 cm H2O.

20. The surgeons will resect the liver using a CUSA or ultrasonic
aspirator having first removed the gallbladder and mobilised the
liver. This dislodges hepatic cells leaving vessels intact, so allowing
them to be clipped.
Other alternatives are the clamp crushing technique or the
hydrojet.
Radiofrequency heated devices to reduce blood loss are also under
development.
Electrical cautery with bipolar forceps is also often used. The cut
surface of the liver is often cauterised with argon beam coagulation,
then sealed with fibrin glue and haemostatic pads towards the end of
the procedure.
Towards the end of the procedure it is important to adequately
refill the circulation to enable the detection of bleeding points..

21.  Prior to closure it is helpful for the surgeon to guide a nasojejunal
feeding tube through the pylorus and beyond, as the anaesthetist
advances the tube.
Once in position the surgeon can maintain the position of
the tube as any slack or kinks are removed by the anaesthetist
pulling back on the tube and then after flushing with saline,
removing the central stiffening wire.
The tube should then be flushed again to reduce the chance of
blockage.
It is common to start low dose feeding at 10 ml/h once the patient is
fully awake, later on the day of surgery. This can then be increased as
tolerated.
A nasogastric tube is also usually positioned soon after induction
together with the preliminary placement of the nasojejunal tube.

22. In radiofrequency ablation a thin needle is inserted into the
metastasis within the liver. The tip is heated to 80-100 C, resulting
in destruction of tumour tissue.
This can be used to control some metastases percutaneously or as
an addition to surgery in difficult to access areas of the liver. This has
the potential to cause a high degree of tissue destruction and needs
careful control. It may cause a SIRS response.
Patients with more than two nodules of hepatocellular carcinoma
and hepatitis c have a high rate of recurrence.

23. Problems of a low CVP
Perfusion may be compromised, especially in patients with poor
left or right ventricular function. In an effort to maintain perfusion
in a reduced CVP situation, many anaesthetists use an inotrope or
vasoconstrictor such as a low dose of dobutamine (2-5 ug/kg/min)
or noradrenaline (0.05 ug/kg/min).
In the case of dobutamine it is important to ensure heart rate does
not rise too high because of its muscle vasodilatory and chronotropic
tendencies.
Glyceral trinitrate infusions or diuretics have sometimes been used to
lower CVP, but generally are not necessary.

24. When running with a low CVP, a sudden loss of blood will
rapidly produce severe hypovolaemia. This is why it is vital to have
the ability to rapidly infuse warmed fluids or transfuse blood, using
a rapid infusor designed for the purpose that can protect against
inadvertent air infusion.
 Again it is important not to excessively compensate for fluid loss
and produce a high CVP that further compromises the surgeon’s
ability to regain control.

25. Watching the cut surface of the liver from the foot end of the patient
may help with understanding how the surgeon is coping.
Be aware that the surgeon or his assistant may compress the inferior
vena cava with hands, retractors or packs and seriously reduce venous
return.
Therefore it is important to watch what they are doing and avoid
having a “blood brain barrier” that can’t be seen over.

26. Air embolism is a hazard of a low CVP. It is important to watch for
sudden falls in cardiac output, with a fall in end-tidal CO2. If suspected
infuse fluid rapidly, inform the surgeon, who may be able to prevent
further air entering, give 100% oxygen and aspirate from PAFC if one
is in situ.
In a massive embolism it may be possible to aspirate air.
Small air embolisms are seen very commonly if looked for using
transoesophagealDoppler techniques, however major embolisms are
far less common.
This is in particular a potential risk during CO2 pneumoperitoneum
for major laparoscopic liver surgery. Intrapulmonary arteriovenous
shunts in cirrhosis have been described as a cause of paradoxical air
embolism and in a small number of patients there may be an
anatomical route from the right to left heart.

27. Clamping of the hepatic artery and portal vein
Blood loss is reduced by hepatic arterial and portal vein occlusion.
Prolonged clamping will cause warm hepatic ischaemia, with the
potential for infarction as sometimes evidenced by a sharp rise in ALT
and AST seen 24 h later. Most surgeons will try to restrict clamping to
15 min at a time and then will reperfuse for 5min with the hope of
allowing the liver to recover.
Microcirculatory changes associated with reperfusion reduce sinusoidal
blood flow and prolong hypoxic effects. Intermittent clamping up to 90
min in total appears reasonably well tolerated in non-cirrhotic livers.
Exactly what is happening in terms of liver reperfusion injury is unclear
during this time, but it does also allow the restoration of blood drainage
from the gut.

28. During clamping and particularly after major resections regular
checking of blood sugar levels usually most conveniently from
arterial blood gases is important.
It is common practice to run a background infusion of 5% glucose
during liver resections for this reason.
There is some evidence mainly from hepatic transplants that N-
acetyl cysteine may reduce hepatic damage during clamping.

29. Postoperative care
 The vast majority of liver resections can be woken up from
anaesthesia and extubated at the end of surgery. Occasional
exceptions are those who have experienced heavy bleeding and are
still too cold or acidotic to awaken.
Waking at the end of surgery is important to minimise additional
sedation and lung atelectasis due to prolonged ventilation.
In large resections there is a risk of prolonged
neuromuscular blockade, which can be reduced by using
neuromuscular blocking (NMB) drugs that are not metabolised
hepatically and by reducing the amount and frequency of use.

30. Reversal agents are important as is electrophysiological testing
with a nerve stimulator.
It is often only necessary to use a dose to facilitate intubation and
sometimes for wound closure. During the rest of surgery the effect of
the epidural and other anaesthetic drugs is usually sufficient to relax
the abdomen.
If epidural analgesia has been employed this will cover abdominal
pain, although drain sites can be problematic especially if the tissues
are too tightly stretched around the drain.
Unfortunately, shoulder tip pain may occur due to referred pain
from close to the diaphragm because of the similar dermatomal
distribution. Tramadol is often used to combat this pain because of
its multimodal mechanisms of action.

31. Patients with 40% or smaller resections who are at low risk of
hepatic failure can be managed in a similar way to most other major
laparotomies.
Early postoperative nasojejunal feeding may help maintain gut
function and immunocompetence.
Larger hepatectomies are often cared for using protocol based care.

32. The possibility of hypoglycemia may necessitate a glucose infusion.
Secondary hyperaldosteronism is common, which promotes retention
of sodium and water and leads to oedema.
 Intravascular volume expansion may be aided by salt-poor 20%
albumin.
Correction of electrolyte disorders is commonly needed especially
potassium and phosphate.
A proton pump inhibitor may be needed.
 Lactulose is normally introduced if there are any signs of
encephalopathy.

33. Complications
Postoperatively,complications are frequent. Therefore it is
commonpractice for hepatic resections to spend sometime
postoperatively ona high dependency unit.
This becomes progressively more important
as the size of resection increases and the number of
comorbiditiesrises.

34. Intraoperatively, the commonest complications are hypotension
and bleeding.
 Median blood loss for a liver resection is under 0.5 l,
however, the potential for massive haemorrhage exists.
This means
that in most cases transfusion can be avoided,which has been shown
to reduce the frequency of recurrence of malignancy and reduce the
number of postoperative infections.
However,
if transfusion requirements are likely to exceed 4 units of blood the need
for FFP should be anticipated early to maintain clotting as close to
normal as possible, with early administration of platelets when needed.

35. Respiratory:
Most common are-atelectasis and subsequent pneumonia. It is
common to find basal collapse especially on the right side, which
may be compounded by a pleural effusion, especially if there is
a source of inflammation below the diaphragm.
 Inadequate pain relief or postoperative drowsiness secondary to
analgesic or other drug therapy will lead to failure to clear secretions
and reexpand the lungs.
.

36. Some anaesthetists will recruit the lungs at the end of surgery to
reduce postoperative atelectasis.
Increasing postoperative atelectasis should be treated by early CPAP
and where possible the patient should sit out or even mobilise with
support.
As with all major surgery DVT formation and pulmonary embolism
are possible and may necessitate use of DVT filters in the inferior
venacava, in those already on treatment or suffering from for DVT or
pulmonary embolism, because of the high risks of bleeding
associatedwith anticoagulation soon after liver surgery

37. Gastrointestinal: The enhanced blood supply to the regenerating
hepatic remnant is associated with increased splanchnic blood flow
and cardiac output. Fifty percent of patients will develop ascites
transiently, which can add to hypovolaemia.
Ileus and failure to absorb are common.
If the patient can be kept stable then recovery usually occurs. Signs of
liver ischaemia as evidenced from rising liver enzymes are common in
the 24-48 h after surgery.
During surgery, surgeons will normally try to remove liver
tissue with compromised blood supply. Sudden marked rises in liver
enzymes or unexpected hypoglycemia should prompt concerns over
major ischaemia with potential portal vein thrombosis as a diagnosis.
Doppler ultrasound may clarify the situation.

38. Markers of liver function:
As well as traditional liver function
tests such as liver enzymes or bilirubin, there are markers of liver
synthetic function such as prothrombin time (extrinsic or tissue
pathway of coagulation which relies on hepatic production of
clotting factors I, II, V, VII, IX, X and XI, protein C, protein S and
antithrombin), albumin and urea.
 The urea cycle occurs in the liver where it is formed from ammonia,
which itself comes from metabolism of amino acids. Unsurprisingly, if
this five stage process does not occur it leads to accumulation of
ammonia and induces hepatic encephalopathy.

39. A climbing lactate may indicate poor
perfusion of an organ or organs in the body, but may also be a sign
of falling liver function.
To Reduce liver damage , Reducing clamp time is an important
factor in this.
However, the administration of N acetyl cysteine
appears to be beneficial even in non-paracetamol induced hepatic
failure and also acts as an antioxidant.

40. Renal System:
Oliguria is most commonly due to hypovolaemia.
Cardiovascular:
either hypovolaemia or arrhythmia in those
with pre-existing heart disease or sepsis from chest or abdomen.

41. CNS:
Drowsiness is most commonly related to opiates or other
accumulating drugs. However, in the face of increasing liver failure,
hepatic encephalopathy is possible as is hypoglycemia. Checking
ammonia and glucose levels is important.
Hallucinations may be related to opiate accumulation. If opiates are
being used these should be discontinued or removed from the epidural
mix.

42. In summary hepatic resection is a major operation with the
additional risk of potential hepatic failure and major bleeding
and the hazards associated with a large upper abdominal
incision.
However, with adequate selection and adequate
perioperative care, 30 day mortality can fall to around 3%.
Further reductions and improvements in safety for patients
with initially reduced liver function may be possible in the
future.