Hepatic Pathophysiology Flashcards

Question

Cirrhosis CAUSES

Answer 1

Alcohol abuse Non-alcoholic fatty liver disease Chronic active hepatitis (B & C) Chronic biliary inflammation or obstruction

Answer 2

Variceal hemorrhage d/t portal HTN Intractable fluid retention → ascites Hepatic encephalopathy or coma

Answer 3

Surgical risk r/t hepatic impairment degree ``` Total bilirubin Serum albumin INR Ascites Hepatic encephalopathy ``` Points 5-6 = Class A 100% 1 year → 85% 2 year survival 7-9 = Class B 80% → 60% 10-15 = Class C 45% → 35%

Answer 4

Portal hypertension S/S → gastroesophageal, hemorrhoidal, periumbilical, retroperitoneal varices, & dilated abdominal wall veins Variceal bleeding treatment - IVF, blood products, vasopressin, propranolol, balloon tamponade, endoscopic sclerosis or varices ligation Anemia, thrombocytopenia, coagulopathy, leukopenia Excessive blood transfusions → encephalopathy Correct coagulopathy before surgery Replace clotting factors w/ blood products (i.e. FFP & cryoprecipitate) Platelet count <100,000 → transfusion

Answer 5

Hyperdynamic circulatory state ↑CO & generalized peripheral vasodilation AV shunts R → L develop in systemic & pulmonary circulation Cirrhotic cardiomyopathy d/t AV shunts & ↓blood viscosity → ↑CO Alcoholic cardiomyopathy → CHF

Answer 6

Hyperventilation common & results in 1° respiratory alkalosis Hypoxemia frequent d/t R → L shunt - ↑anomalous AV communication - V/Q mismatch - 40% CO involved ↓lung volumes (particularly FRC) d/t ascites fluid elevates the diaphragm → atelectasis CXR & ABG Paracentesis to treat massive ascites w/ pulmonary compromise

Answer 7

Ascites, edema, electrolyte abnormalities, hepatorenal syndrome Portal HTN ↑hydrostatic pressure fluid transudation across the intestine into the peritoneum Hypoalbuminemia ↓plasma oncotic pressure → fluid transudation Protein-rich lymph fluid 2° distortion & obstruction lymphatic channels Renal Na+ & H2O retention d/t hepatorenal syndrome ↓renal perfusion, altered intrarenal hemodynamics, enhanced proximal & distal tubule Na+ reabsorption, impairment free water clearance Dilutional hyponatremia Hypokalemia - excessive K+ loss 2° hyperaldosteronism or diuretics Judicious preop fluid management - Ascites & edema diuresis over several days - Loop diuretics only after bed rest, Na+ restriction, & Spironolactone therapy failed Preserve renal function Correct intravascular fluid deficits w/ colloid infusion

Answer 8

Functional deficit in patients w/ cirrhosis Causes: GI bleeding, aggressive diuresis, sepsis, major surgery S/S: Na+ retention, progressive oliguria, azotemia, intractable ascites High mortality rate Treatment = supportive & often unsuccessful unless liver transplant performed

Answer 9

Hepatic encephalopathy - mental status alterations, asterixis, hyperreflexia, EEG changes, ↑ICP Treat encephalopathy preop *Avoid sedatives Metabolic encephalopathy r/t hepatocellular damage & degree portal blood shunting directly into systemic circulation → accumulation toxins originating from GI tract (ammonia, methionine metabolites, short chain fatty acids, phenols)

Answer 10

``` 1° GI bleeding ↑dietary protein intake ↑ammonia Hypokalemic alkalosis d/t vomiting or diuresis Infections Worsening liver function ```

Answer 11

``` CNS sensitivity Vd Protein binding Metabolism Elimination ``` Titrate, titrate, titrate

Answer 12

↑Vd highly ionized NMBs ↑loading dose ↓hepatic elimination ↓maintenance dose

Answer 13

Cirrhotic liver dependent on hepatic arterial blood flow d/t reduced portal blood flow Avoid anesthetic agents that potentially ↓hepatic arterial blood flow Regional anesthesia w/o thrombocytopenia or coagulopathy avoid hypotension Propofol or Thiopental induction w/ Isoflurane Choice NMB = Cisatracurium Opioid supplementation ↓volatile agent requirement but prolonged elimination 1/2 time → prolonged respiratory depression RSI induction w/ cricoid pressure CV unstable patient or w/ active bleeding → awake intubation

Answer 14

``` 5-lead EKG ABGs to evaluate acid-base status R → L shunts A-line to monitor rapid BP changes (excessive bleeding, fluid shifts, surgical manipulations) CVP or PAP UOP Large bore IVs ```

Answer 15

Na+ restriction preop Intraabdominal procedures associated w/ excessive bleeding (venous engorgement d/t portal HTN, adhesions from previous surgery, coagulopathy) & fluid shifts (ascites evacuation & prolonged surgical procedures) Anemia + coagulopathy → blood transfusion preop Significant transfusions → citrate toxicity

Answer 16

Hepatic metabolism Cirrhosis impairs citrate metabolism Citrate bind to serum Ca2+ & leads to hypocalcemia IV Ca2+ often necessary to reverse the negative inotropic effects r/t ↓iCal

Answer 17

Cholestasis - impaired bile outflow Most common cause = biliary tract extrahepatic obstruction Also caused by intrahepatic obstruction ↑conjugated bilirubin >50% ↑alkaline phosphatase OR cholecystectomy d/t cholecystitis Treatment - NG suction, IVF, antibiotics, opioid analgesics High bilirubin levels associated w/ renal failure Long-term extrahepatic biliary obstruction associated w/ 2° biliary cirrhosis & portal HTN

Answer 18

Obstruction d/t gallstones, stricture, or tumor w/in common bile duct Treatment - surgical (remove blockage)

Answer 19

Bile flow suppression or stoppage at hepatocyte or bile canaliculus level Most commonly results from viral hepatitis or idiosyncratic drug reaction Treatment - medical (inflammation)

Answer 20

Cholelithiasis Present w/ biliary colic 2° to cystic duct obstruction Gallstones obstruct pancreatic duct → acute pancreatitis

Answer 21

Concomitant chills or high fever suggest an ascending bacterial infection of the biliary system

Answer 22

Vitamin K deficiency d/t extrahepatic biliary obstruction Full response requires 24 hours PT unable to correct prior to surgery after vitamin K admin FFP

Answer 23

Opioids → problematic w/ intraop cholangiogram d/t induce Sphincter of Oddi spasm → false + Treatment = Naloxone or Glucagon Biliary tract obstruction expect prolong DOA in drugs dependent on biliary excretion (i.e. Propofol or Ketamine) Agents dependent on renal excretion are preferable Monitor UOP Maintain periop diuresis

Answer 24

Common surgeries - laceration repairs, abscess drainage, tumor resection 80-85% liver able to be resected Complications - blood loss Cirrhosis complicates anesthetic management & ↑periop mortality Multiple large bore IVs, fluid/blood warmers, rapid infusion devices, A-line, CVP, avoid hypotension Admin antifibrinolytics ↓blood loss (i.e. Aprotinin, Aminocaproic acid, Tranexamic acid) Hypoglycemia following liver resections Abscess drainage complicated by peritoneal contamination

Answer 25

Bleeding Sepsis Hepatic dysfunction Mechanical ventilation postop after extensive resection

Answer 26

Hepatitis (liver inflammation) d/t virus/toxin/fatty liver disease → Acute (fulminant liver failure) d/t Hep B/D or Acetaminophen → 80-90% hepatocyte function loss → encephalopathy/coagulopathy → 1° cause death cerebral edema d/t ↑NH3 in brain & accumulation glutamate & neuronal swelling Chronic liver disease d/t alcohol/Hep C/non-alcoholic fatty liver disease → hepatocellular death or cirrhosis Hepatocellular death ↓synthesis/clearance/metabolic derangement → encephalopathy/coagulopathy Cirrhosis → risk hepatocellular cancer or portal HTN Portal HTN → ascites/varices/death d/t varices bleeding

Answer 27

``` Cirrhosis 6-80% mortality - Lap chole 1-6% - TURP 7% - Umbilical herniorrhaphy 13% - Non-lap biliary 20% - Abdominal trauma 47% - Peptic ulcer 54% - Emergency abdominal 57% - Emergency cardiac 80% Chronic hepatitis 0% Hep C lap chole 0% Acute hepatitis ex lap 100% Obstructive jaundice abdominal surgery 5-60% ```