Liver Anesthesia Mgmt & Surgeries

Question 1

What does sympathetic activation due to the hepatic blood flow?

Answer 1

Vasoconstriction of hepatic artery leads to decreased hepatic blood flow.

Question 2

What does Beta Adrenergic stimulation due to hepatic blood flow?

Answer 2

Vasodilation of the hepatic artery leads to increased hepatic blood flow.
-Beta Blockers decrease blood flow.

Question 3

What are the effects of General Anesthesia on the Liver?

Answer 3

-Reduction in blood flow (dec CO and dec MAP)
-Volatiles: Isoflurane is the best option for a liver case

Question 4

What are the effects of Regional Anesthesia on the Liver?

Answer 4

-Likely not doing RA on these patients due to bleeding issues
-Sympathectomy affects Splanchnic circulation (Liver, GB, omentum, spleen, and pancreas)
-Spinal nerves T3-T11
-Reduced splanchnic blood flow

Question 5

How do the different volatiles affect Liver function?

Answer 5

-Isoflurane increases hepatic blood flow through direct vasodilatory properties
-Desflurane has similar effects to isoflurane, but is more expensive. Can lead to more HD instability.
-Sevoflurane undergoes hepatic biotransformation, producing organic and inorganic fluoride ions (generally below nephrotoxic levels). No significant clinical toxicity is reported with Sevo

Question 6

How does the surgical site affect liver function?

Answer 6

-Upper abdominal surgical sites can cause decreased hepatic blood flow
-Traction on the abdominal viscera may cause reflex dilation of splanchnic capacitance vessels and thereby lower hepatic blood flow.

Question 7

How does mechanical ventilation effect liver function?

Answer 7

Increased airway pressures:
-Decrease venous return
-Reduce CO

PEEP: further reduces venous return. Not recommended to use if you’re having HD instability due to reduction in venous return.

Question 8

How do opioids affect Liver function?

Answer 8

-Opioids cause spasm of the Sphincter of Oddi
-Sphincter of Oddi is what allows flow of bile and pancreatic secretions into the duodenum
-Spasm = obstructed flow = increased pressure between bile duct and duodenum.

Question 9

What should be assessed on the pre-op evaluation of a patient with liver disease?

Answer 9

Physical signs:
-Jaundice
-Petechiae
-Ascites
-Dependent edema
-Altered Mental Status
These suggest significant liver disease is present.

Labs:
Albumin
CBC
Coagulation studies
BMP
BUN
Cr
Glucose
ALT & AST
T&S, cross-match

Question 10

What is important to know regarding laboratory testing of liver function?

Answer 10

-No single lab test to assess liver function
-Huge functional reserve: Significant disease before seen clinically (Liver will compensate for awhile)

Question 11

What is indicated by the AST/ALTs?

Answer 11

Destruction at the parenchymal (tissue) of the Liver
-AST: NOT specific to Liver
-ALT: Liver specific. Signifies leakage coming from damaged hepatocytes.

Obstructive disorders are detected by Alk Phos

Question 12

What is the Child-Pugh Score?

Answer 12

Scores the severity of Liver Disease.
Calculated by adding the points based on the five features:
-class A = 5 or 6
-class B = 7–9
-class C = 10 and higher.
The classes indicate the severity of liver dysfunction: Class A is associated with a good prognosis, and class C is associated with limited life expectancy.

Question 13

What are the parameters assessed on the Child-Pugh Score?

Answer 13

Encephalopathy
Ascites
Bilirubin (mg/dL)
Albumin (g/dL)
PT (INR)

Question 14

What values are “Low Risk” on the Child-Pugh Score?

Answer 14

1 point each.
-Encephalopathy: None
-Ascites: Absent
-Bilirubin: <2
-Albumin: >3.5
-PT/INR: <1.7

Question 15

What values are “Moderate Risk” on the Child-Pugh Score?

Answer 15

2 points each.
-Encephalopathy: Moderate
-Ascites: Slight
-Bilirubin: 2-3
-Albumin: 2.8 - 3.5
-PT/INR: 1.7 - 2.3

Question 16

What values are “High Risk” on the Child-Pugh Score?

Answer 16

3 points each.
-Encephalopathy: Severe
-Ascites: Moderate
-Bilirubin: >3
-Albumin: <2.8
-PT/INR: >2.3

Question 17

What is the Model for End-Stage Liver Disease (MELD) Score?

Answer 17

MELD is a scoring system that assesses the severity of chronic liver disease. It is useful in prioritizing recipients for liver transplant, as it predicts the outcome based on the calculated score. MELD uses the patient’s values for serum bilirubin, serum creatinine, and the INR(PT) to predict three-month survival (interpretation of MELD score is given in).

If score is >/= 40, 100% mortality rate

Question 18

What is the pre-op anesthesia plan for a patient with Liver dysfunction?

Answer 18

-Pre-op sedation may be unnecessary if encephalopathy
-Huge aspiration risk due to impaired gastric motility. Need Reglan, Zantac, RSI
-Invasive monitors: Art Line and possibly PAC if monitoring for Pulmonary HTN with liver transplant

Question 19

What do you have to consider when using Regional Anesthesia in a patient with Liver dysfunction?

Answer 19

-Platelet and Coagulation status (No NA/RA if plts <100,000)
-Benzos, Barbs, and Opioids are highly protein bound = decrease the dose
-Theorized to have increased benzodiazepine receptors = decrease the dose

Question 20

What is the preferred induction for a patient with Liver dysfunction?

Answer 20

-RSI due to impaired gastric function and inc abdominal pressure from ascites
-Patients will be short of breath. Need reverse T burg and Cricoid pressure
-Succinylcholine may have prolonged DOA due to decreased plasma cholinesterase. Also risk with hyperkalemia and immobile/debilitated patients
-DOA of MR will be extended if hepatically cleared.
-Volatiles: Isoflurane is best

Question 21

Can you use N2O in a patient with Liver Dysfunction?

Answer 21

Avoid the use of Nitrous Oxide due to possibility of expansion of the bowel (bowel distention) and sympathomimetic effect causing hepatic vasoconstriction

Question 22

What are intra-op causes of Liver Hypoxia?

Answer 22

-Inadequate ventilation (Diaphragm is restricted by large belly. Need to get proper Vts)
-Excessive bleeding
-Hypovolemia (Intravascularly dry)
-Hypotension
-Inadequate C.O.
-* vasoconstrictive reduction in splanchnic blood flow

Question 23

What are your intra-op hemodynamic goals with the patient with Liver dysfunction?

Answer 23

To optimize central & systemic arterial perfusion pressures.
-Maintain C.O.
-Avoid arterial HOTN
-Minimal vasoconstrictive agents (1st line tx of hypotension is fluid)
-Adequate anesthesia
-Decrease surgically induced stress response (give fentanyl/precedex with incision)

Question 24

Are opioids appropriate for a patient with liver dysfunction?

Answer 24

-Opioids are dependent on hepatic metabolism, use caution
-Decrease the dose
-Remifentanil is a good choice (metabolized in the blood)
-Morphine is not appropriate

Question 25

Why is morphine not appropriate for use in a patient with Liver dysfunction?

Answer 25

It releases Histamine. Nagelhout: -Morphine is metabolized in a phase II reaction, undergoing glucuronidation in the liver, and should be titrated cautiously or avoided in patients with significant liver disease.

Question 26

What is Octreotide used for?

Answer 26

-Somatostatin analog -Used to decrease venous return to portal circulation

Question 27

Why do you want to maintain normocarbia intrap?

Answer 27

To optimize oxygen extraction and optimize organ perfusion.

Question 28

Why do you want to avoid hypothermia in patients with liver dysfunction?

Answer 28

-Worsens coagulopathies -2 forced air warming blankets -Warm IVF

Question 29

What are the anesthetic concerns with an acutely intoxicated patient?

Answer 29

-They will have labile VS. try to keep things consistent. -Aspiration precautions -Brain is less tolerant of hypoxia -Circulating catecholamines are increased (labile VS) -Increased bleeding due to dysfunctional platelets.

Question 30

What are indications for a Liver resection?

Answer 30

-Carcinoma -Trauma (Liver Laceration) -Living Donor The liver is unique, it can regenerate itself.

Question 31

When is Radiofrequency Ablation performed?

Answer 31

To non-resectable tumors. -Can be done for palliative reasons -Patients can range from healthy to super sick. -Uses US to image where the tumor is.

Question 32

What is Irreversible Electroporation (IRE)?

Answer 32

-Used with hepatic resection, open and laparoscopic microwave ablation -Locally treat advanced pancreatic/ liver tumors -Alone or with resection -Long needles (Antennas) are placed around the tumor and deliver high voltage DC current. -Extremely painful during current delivery, but none after. (Anticipate this and medicate up front to save your emergence) Location of tumor determines the pain. -If they get around celiac plexus, may find HD instability occurring. Communicate with staff. -If they are near the dome of the liver, there is a 10% chance of v tach occurring. Be ready for that.

Question 33

What is the anesthesia management of Irreversible Electroporation (IRE)?

Answer 33

-Need cardiac workup pre-op -Full MR (0/4 twitches) -Keep fully relaxed until the very end (bucking during electricity is bad) -Remi gtt works well (0.5 - 2 mcg/kg/min) -May see bradycardia when they start delivering high current

Question 34

What is a TIPS procedure?

Answer 34

Transjugular Intrahepatic Portosystemic Shunt. -Right IJ→IVC →R hepatic vein →channel via liver parenchyma to portal vein -Shunting high portal circulation directly to systemic circulation via a stent. -Done under GA with patient relaxed -Relieves portal back pressure, reducing esophageal varices bleeding and ascites. -Palliative measure

Question 35

What are complications of a TIPS procedure?

Answer 35

-Liver puncture -Hepatic Artery puncture (Remember that Hepatic Artery and Portal Vein are parallel) -PE -Encephalopathy because diverted blood does not undergo hepatic metabolic processes

Question 36

What is Chemoembolization?

Answer 36

-Sclerosing vessels to shunt blood to healthy vessels -Cuts off blood supply to tumors before doing surgery to help with massive blood loss -Usually GA -Femoral artery to hepatic artery

Question 37

What is an ERCP?

Answer 37

Endoscopic Retrograde Cholangiopancreatography. -Done in NORA -Patient is prone -Uses X-Ray -Shared airway with gastroenterologist -Very fast, can't use a lot of MR. Can use succ or low-dose Roc. -Go down esophagus with scope into stomach/duodenum, usually if you have a biliary stone. Place a stent to relieve obstruction. -Need RSI due to risk of aspiration (bile filled gallbladder)

Question 38

Describe induction for a Liver Transplant.

Answer 38

-Drug metabolism & protein binding is effected -Avoid hypoxemia due to ascites already causing decreased lung volumes due to diaphragm being unable to descend -RSI due to aspiration risk from delayed gastric emptying -Monitor PA pressures

Question 39

What are the 3 phases of a Liver transplant?

Answer 39

Dissection Anhepatic Reperfusion (neohepatic)

Question 40

Describe the Dissection phase of liver transplant?

Answer 40

-Mobilizing vascular structures around the liver. Dissect out the hepatic artery, portal vein, and vena cava -Cardiac instability during this phase. Potential hemorrhage, venous pooling, impaired venous return, and issues with surgical retraction -Drainage of ascites = massive fluid shifts

Question 41

Describe the Anhepatic phase of Liver Transplant

Answer 41

-Isolate common bile duct -Remove native liver -May need veno-venous bypass to maintain HD stability

Question 42

Describe the Reperfusion (Neohepatic) phase of Liver Transplant

Answer 42

-New liver is placed. Pay attention to the surgical field -Will unclamp and reperfuse organ, may get some HD instability (has lactic acid building up in area - causes massive vasodilation) -Reanastomosis of major vascular structures -Allograft flushed: getting out air, debris, and preservative solutions -HD instability: dysrhythmias, bradycardia, hypotension, and hyperkalemic arrest