Mod13: Liver Transplants Flashcards
Liver Transplants
Where are liver tpx performed?
in many centers across the country
Liver Transplants
Where is the healthy liver obtained?
From deceased donor who has not suffered liver injury
Liver Transplants
How is the healthy liver transported?
in a cooled saline solution
Liver Transplants
How long could a healthy liver remain viable in the cooled saline solution prior to transplantation?
Up to 8 hours
This time permits analysis to determine blood and tissue donor-recipient matching
Liver Transplants
How long does a liver transplant operation last?
can take 12 hours to complete
Liver Transplants
Why do liver transplant operations require large volumes of blood transfusions?
Because the surgical procedure involves cutting and reconnecting multiple major blood vessels
Liver Transplants
For which conditions is liver tpx the definitive tx for?
Decompensated cirrhosis
Unresected or unresectable hepatic malignancy
Acute liver failure & other metabolic dz that irreversibly injure the liver
Liver Transplants
Why are post liver Tpx pts at high risk of developing atelectasis and small airway closure?
Large, transverse upper abdominal incision
Associate with high intensity pain
Incision is also close to diaphragm
Atelectasis and small airway closure due to not taking deep enough breaths because of pain
Pt should be coached to take deep breaths
Liver Transplants
Which vascular structures are affected during liver tpx?
Inferior vena cava
Hepatic veins
Hepatic areteries
Portal veins
Bile duct
Liver Transplants
Most pts requiring liver tpx are very sick. Which circumstance usually gets them to the top of the tpx list?
Being hospitalized, and requiring ICU care
Liver Transplants - Anesthesia Techniques
True or False: there is a specific anesthetic protocol for liver tpx
False
Liver Transplants - Anesthesia Techniques
True or False: it is recommended that each liver transplant facility comes up with a uniform approach to be used initially during transplantation.
True
Liver Transplants - Anesthesia Techniques
What’s an appropriate anesthetic technique for liver Tpx?
GETA with RSI
Liver Transplants - Anesthesia Techniques
Which drugs would you use for induction and intubation?
Fentanyl
Sodium pentothal/etomidate
Low dose non-depolarizing muscle relaxant (Cis), and
Succinylcholine
Liver Transplants - Anesthesia Techniques
Which drugs would you use for maintenance of anesthesia?
Fentanyl
Benzodiazepines
Non-depolarizing muscle relaxant (Cis)
Isoflurane in air/oxygen
Liver Transplants - Anesthesia Techniques
Which ventilatory strategy could you use to reduce the risk of air emboli and to prevent atelectasis during liver tpx?
Mechanical ventilation with 5 cmH2O of PEEP
Liver Transplants - Anesthesia Techniques
Why should Nitrous oxide be avoided in liver tpx?
Can lead to bowel distension
Issues with surgical exposure, since bowell and liver share the same area
Liver Transplants - Preparation
What are considered standard monitors during liver tpx?
Central line for fluid replacement
(insert before or after induction - <u>add two large bore IVs 16g</u>)
CVP for monitoring fluid status
A-line for beat-to-beat monitoring of heart rate/pressure and multiple blood draws
Foley catheter for urine output
TEE for CO and wall motion monitoring
Liver Transplants - Preparation
Why should you have a rapid transfuser available
In case you must administer large amounts of volume/blood in a very short period of time
Liver Transplants - Preparation
Why should you have Fluid and body warmers available
The prevent hypothermia
Liver Transplants - Preparation
What should you do in anticipation of LARGE blood loss?
Contact Blood Bank
Have large amounts of blood readied
Liver Transplants - Intraoperatively
A liver transplant last 12 hours on average, with a range of 4 to 18 hours and is divided into three phases. What are those phases?
Preanhepatic (Dissection)
Anhepatic (No liver connected)
Neohepatic (Revascularization
Liver Transplants - Intraoperatively - Preanhepatic
When does the Preanhepatic phase starts? when does it end?
Sarts at incision
Ends when all the vessels are clamped off (Vascular exclusion),
and the native and non functioning liver is taken out (hepatectomy)
Liver Transplants - Intraoperatively - Preanhepatic
When the liver is dissected in the Preanhepatic phase, which vessels does it remain attached to only?
Inferior vena cava
Portal vein
Hepatic artery and
Common bile duct
All except hepatic veins
Liver Transplants - Intraoperatively - Preanhepatic
Which factors in the pt’s history could prolong the dissection part of the Preanhepatic phase
Adhesions from previous abdominal surgery
Liver Transplants - Intraoperatively - Preanhepatic
In the Preanhepatic phase, when would you anticipate large amount of blood loss?
When they start to clamp the different areas and actually cut the vessels
Be ready to transfuse
Liver Transplants - Intraoperatively - Preanhepatic
Which two electrolyte disturbances are commonly associated with liver tpx?
Hyponatremia
Hyperkalemia
Liver Transplants - Intraoperatively - Preanhepatic
Why should you not treat hyponatremia a/w liver tpx too quickly?
…
Liver Transplants - Intraoperatively - Preanhepatic
Hyperkalemia a/w liver tpx must be treated promptly, but which precautions must be taken?
Remember the steps
How do we treat the symptoms
How do we treat the disturbance
How bad is the hyperkalemia
How agressive do we need to be in treating it?
Liver Transplants - Intraoperatively - Anhepatic
When does the Anhepatic phase starts? When does it end?
Starts at the occlusion of vascular inflow to liver being taken out
Ends at Graft reperfusion
Liver Transplants - Intraoperatively - Anhepatic
When is the inferior vena cava clamped above and below the liver? Which other major vessels are clamped at the same time?
Once the dissection is completed and the liver is freed
Hepatic artery and portal vein will be clamped at the same time
Liver Transplants - Intraoperatively - Anhepatic
Once the liver is freed, the inferior vena cava is clamped above and below the liver as well as the hepatic artery and portal vein. What happens next?
The liver is then completely excised and
Veno-venous bypass may be employed at this time
Donor liver is then anastomosed to recipient patient
Liver Transplants - Intraoperatively - Anhepatic
What’s the effect of clamping large vessels (inferior vena cava and portal vein) during the Anhepatic phase of liver tpx on CO and BP
Marked decreases in CO and
Hypotension can be encountered
Occurs when inferior vena cava and portal vein are clamped
Liver Transplants - Intraoperatively - Anhepatic
Which vascular strategy is employed for patients at increased risk during the vena cava clamping?
Veno-venous bypass
Liver Transplants - Intraoperatively - Venovenous Bypass
How does the veno-venous bypass redirects blow flow during liver tpx?
Diverts IVC and portal venous flow to the superior vena cava via the axillary vein
Liver Transplants - Intraoperatively - Venovenous Bypass
What are the benefits of Venovenous Bypass?
Can help minimize:
Severe hypotension
Intestinal ischemia
Build up of acid metabolites and
Postoperative renal dysfunction
Liver Transplants - Intraoperatively - Venovenous Bypass
What risks are a/w Venovenous Bypass?
VAE
Thromboembolism
Inadvertent Decannulation
Liver Transplants - Intraoperatively - Neohepatic
When does the Neohepatic phase starts? When does it end?
Starts with the completion of venous anastomosis
Ends with when circulation to the new liver is completed and blood is allowed to enter the new liver
Liver Transplants - Intraoperatively - Neohepatic
When is circulation to the new liver allowed?
Following completion of venous anastomosis
The venous clamps are removed and circulation to the new liver is allowed
Liver Transplants - Intraoperatively - Neohepatic
Following completion of venous anastomosis the venous clamps are removed and the circulation to the new liver is completed. Reperfusion syndrome may occur. What are possible causes of Reperfusion syndrome?
Cold, acidotic, hyperkalemic solution floading the system
Could happen quickly and as soon as blood flow is resumed
Liver Transplants - Intraoperatively - Neohepatic
What potential risks are a/w reperfusion syndrome?
Emboli - Arrhythmia - Cardiac arrest
Hypotension
Liver Transplants - Intraoperatively - Neohepatic
Which drugs could be used to prophylactically treat risks a/w reperfusion syndrome?
CaCl or Bicarb
Eliminates huge shift when reperfusion occurs
Liver Transplants - Intraoperatively - Neohepatic
Following completion of venous anastomosis the venous clamps are removed and the circulation to the new liver is completed. Ischemia/reperfusion injury is possible. What could be reponsible this?
Endothelial dysfunction and non functioning graft
Happens overtime
Could manifest beyond the Neohepatic phase
Liver Transplants - Intraoperatively - Neohepatic
Following completion of venous anastomosis the venous clamps are removed and the circulation to the new liver is completed. What’s the last structure to be connected?
Common bile duct of the donor is connected to the recipient
Liver Transplants - Intraoperatively - Management of liver reperfusion
When it does occur, how is reperfusion syndrome managed?
Take steps to bring potassium to appropriate level (< 4.0)
(Go back and review how to treat Hyperkalemia and associated symptoms)
Replace calcium to ensure normal (> 5.0)
Correct lactic acidosis (pH normal)
Appropriate volume infusion to maintain euvolemia
Hemoglobin appropriate (9 – 10 for most patients)
Epinephrine 10 mcg/cc attached to iv ready for administration (bolus)
Epinephrine 20 mcg/cc on baxter pump ready for infusion
Communication with surgeon – OK for reperfusion
Liver Transplants - Intraoperatively - Management of liver reperfusion
In the management of reperfusion syndrome, what should be your target potassium level?
< 4.0
Liver Transplants - Intraoperatively - Management of liver reperfusion
In the management of reperfusion syndrome, what should be your target calcium level?
> 5.0
Liver Transplants - Intraoperatively - Management of liver reperfusion
In the management of reperfusion syndrome, what should be your target Hemoglobin level?
9 – 10 for most patients
Liver Transplants - Intraoperatively - Management of liver reperfusion
In liver tpx case, when should you start preparing for reperfusion and potential reperfusion syndrome?
During the initial phases of the case
