anesthesia for organ transplantation (liver, kidney, pancreas, heart) Flashcards
which type of donor grafts have greater success and survival rates?
living donor grafts
how many lives can one organ donor save?
up to 8 lives
what is the most common transplant performed?
kidney
-next is liver
which transplant procedure requires specialized CRNAs
- liver
- heart
describe kidney transplantation considerations
- better survival rate than hemodialysis at 3 yrs.
- ESRD effects on other organ systems make for a challenging anesthetic: uremic conditions, fluid overload
- high incidence of cardiac disease
- high incidence of HTN and diabetes
what are kidney transplant indications?
- glomerular disease
- polycystic kidney disease
- diabetes
- HTN
- congenital diseases
what are some characteristics of ESRD patients?
- cardiac disease most common cause of death
- uremia-induced myocardial depression (weaker heart, weaker pump; more challenging to put to sleep); normalizes after transplantation
- pericarditis
- cardiomyopathies (60% have either RVH or LVH)
- dysrhythmias
- electrolyte abnormalities, especially K+ increase
describe ESRD and cardiomyopathy
- chronic HTN state: increased circulating fluid volume; increased circulating renin levels that vasoconstrict; increased Na+ retention)
- LVH and concentric cardiomyopathy r/t increased afterload
- dilated cardiomyopathy r/t increased fluid volume
- increased afterload and preload
what are the effects of uremic toxins in ESRD?
- pericardial disease
- altered lipid metabolism
- dysrhythmias
- small vessel atherosclerosis (esp. coronaries); increased risk MI, ischemia
- decreased gastric emptying ( >0.4 ml/kg; all are full stomach)
- platelet defects; clots off grafts (hypercoagulation)
- anemia
- uremic frost on skin
what 3 variables determine the surgical outcome of kidney transplant?
- donor management; live vs. deceased
- harvested organ preservation
- perioperative care of organ recipient
what are anesthesia implications for the living donor?
- adequate IV access
- blood availability (**greatest risk is hemorrhage)
- use of balanced salt solution (ensures diuresis; offsets a reduced venous return r/t flank position)
what are anesthesia implications for the brain dead donor?
- graft preservation is highest priority (ensure undamaged)
- loss of sympathetic tone can cause hypotension
- hypotension regardless of volume replacement
- maintain renal perfusion of graft
- use low dose dopamine (1-3 mcg/kg/min)
- avoid high dose vasopressors which can lead to ischemia
- maintain urinary output with diuretic use
what are contraindications to kidney transplant?
- absolute: active infection
- relative: non-compliant drug or ETOH; malignancy; hepatocellular carcinoma with cirrhosis
describe the pre op assessment for kidney transplant
- determine the cause of renal failure (DM #1 cause, HTN #2)
- determine comorbid conditions: ESRD, CAD, DM, HTN, autonomic neuropathy, coagulopathy
- labs/testing: metabolic profile with glucose
- EKG and Echocardiogram with ejection fraction
- CBC with platelet count
- treat patient from renal failure perspective
describe anesthesia implications for kidney transplant
*expect hemodynamic instability
-volume overload, cardiomyopathy, weak pump
-hypotension, bradycardia upon induction if diabetic r/t autonomic neuropathy (inability to compensate for drop in SVR)
have patient hold ACE inhibitor; drops BP
*Type and crossmatch several units (although usu. little blood loss)
*dialyze prior to surgery to optimize fluid volume and electrolyte status
describe intra op considerations for kidney transplants
Large 8-10 inch incision
- GA preferred with excellent muscle paralysis
- regional has been used successfully
- normal saline preferred crystalloid (LR contains K+)
- caution with nondepolarizing NMBA (*Cisatracurium good since Hoffman elimination, organ independent)
- A line for optimal hemodynamic control and frequent blood sampling
- CVL for fluid vol. management and monitoring (*keep CVP b/w 10-15 mmHG)
what commonly happens after unclamping the iliac vessels?
- hypotension
* be prepared to hang vasopressors if needed
what does the graft kidney’s health depend on and how is it maintained?
- perfusion
- avoid hypotension
- studies show vessels of transplanted organs are highly sensitive to sympathomimetics so don’t use high dose vasopressor that can lead to ischemia
- avoid high doses of alpha 1 agonists
- renal dose dopamine is beneficial (D1 receptor; 1-3 mcg/kg)
what determines success of kidney transplant?
urine production
*immediate in most recipients
describe post op considerations for kidney transplant
- completely reverse muscle relaxant
- goal is extubation immediately after surgery
- rarely admit to ICU post op
- post op pain is usually easily controlled
describe pancreatic transplantation
- primarily to cure DM
- nephropathy is present in 50-60% of diabetics causing many to receive kidney and pancreas
- comorbid conditions r/t long term diabetes typically present: autonomic neuropathy, CAD, HTN, ESRD
- usually more of an immunosuppressant challenge; require more immunosuppressant therapy
what are intra op considerations with pancreatic transplants?
- long surgery time
- large, painful incision
- extensive dissection to pancreas (pre op epidurals have shown promise with pain management)
- immunosuppression increased
describe intra op management for pancreatic transplant
- a line to optimize hemodynamic status
- colloids swell the pancreas LESS than crystalloid
- CVL to optimize fluid vol. management and CVP measurements
- frequent blood sampling: electrolytes, serial glucose
- serial glucose checked hourly prior to unclamping and every 30 minutes after
- *success of graft is measured by glucose levels
describe liver transplantation outcomes
- increased discrepancy between organ supply and recipient waiting list (more extensive surgery; all organs may be effected by end stage liver disease)
- 3 yr. survival rate > 75%
- hepatitis C recipients may need retransplanting in the future, causing greater demand for livers
describe end-stage liver disease and pathophysiology
- portal HTN develops: cirrhotic changes increase portal resistance and portal venous pressure > 12 mmHg
- hyperdynamic circulatory state r/t vasodilation and volume expansion
- increased ICP can occur
- ammonia levels lead to encephalopathy
- upper GI bleeding r/t varicosities
what are indications for liver transplant?
- post necrotic (non-alcoholic) cirrhosis (portal HTN, hyperdynamic circulatory status
- biliary cirrhosis
- sclerosing cholangitis
- primary hepatic neoplasia
- alcoholic cirrhosis (usu. must abstain from for > 2 yrs.)
what medical issues usually present with patients requiring liver transplant?
- hepato and porto-pulmonary syndrome: results in decreased PaO2 and shunting; resolves after transplantation
- cardiac status: hyperdynamic state (ascites, SVR low, BP normal to low); HR increased
- coagulation disorders (most challenging): decreased factors II, V, VII, IX, X, protein C, S, antithrombin III; thrombocytopenia lead to increased bleeding
- *require frequent transfusions
- accompanying renal disease common: hepatorenal syndrome (r/t liver decreased vasodilators and increased vasoconstrictor factors; perfusion deficit to kidney)
describe liver transplant pre op
- extensive multi-specialty workup: hematology-coagulation studies; pulmonology; cardiology; nephrology
- cardiac eval: EKG; echo (EF, cardiomyopathy, portal HTN, pulmonary HTN); arteriogram (assess vascular issues); right heart cath (assess pulm. vascular status)
- type and crossmatch and blood product preparation
- 10 units PRBCs, 10 units FFP, Platelets, cryoprecipitate
describe liver transplant monitoring
- correct coagulopathy prior to line placement
- need dependable large bore IV access for fluid and blood administration
- a line for hemodynamic instability and frequent bloodwork
- CVL- CVP measurement (used in 50% of centers)
- telemetry
- TEE (used in 11% of centers)
- PA catheter (used in 30%): assess pulmonary HTN
what are the three stages of liver transplant procedure?
- dissection: extensive lysis of adhesions
- anhepatic: removal of native liver and implanting donor
- reperfusion (neohepatic): anastomosis, restore hemostasis , reperfusion
- *complex and challenging management (fluid shifts, electrolytes up and down, and severe hypotension)
what are intra op considerations during liver transplant?
1) liver failure and drug metabolism
- decreased biotransformation
- hypoalbuminemia causes altered protein binding
- altered volume of distribution (fluid overload)
2) hemodynamic fluctuations
- clamping and unclamping the portal vein and vena cava
- veno-venous bypass (VVB) used in 50% instead of clamp
3) venous air embolism upon reperfusion of the hepatic graft, reperfusion syndrome
4) significant coagulopathy (anticipate significant blood loss)
5) encephalopathy (increased ammonia levels)
describe intra op management of liver transplant
- varies between institutions
- extensive blood and fluid status management
- challenge to pharmacologically manage
- oral gastric tube
- keep normothermic: ice cold donor liver; worsens coagulopathy and drug metabolism
- avoid N2O: intestinal distention
- impaired insulin-mediated glucose uptake: hyperglycemia
- renal alterations hyperkalemia, hyponatremia (no rapid replacement with 3% saline, cause pontine myelinolysis)
- *severe coagulopathy and blood most significant issue with liver transplantation: marked acidosis and hypocalcemia occur
what causes the need for extensive blood and fluid status management with liver transplant?
- ascites decompression upon incision causes hypotension
- manipulation of liver impedes venous return decreasing preload and CO
- inferior vena cava occluded causes severe hypotension and > 50% reduction in CO
what causes a pharmacologic challenge with liver transplant?
- removal of one liver, implanting another
- NMBA used to gauge function of new liver (is it biodegrading NMB?)
- beta blockers for varices bleeding (decreased bleeding)
what is considered with oral gastric tube insertion during liver transplant?
- decompress gastric cavity to increase liver exposure
- expect bleeding r/t varices and coagulopathy
- *insert delicately
what actions can be taken to keep the pt. normothermic with liver transplant?
- run all fluid through warmer
- used forced warm air and heating blankets
describe heart transplantation
- definitive treatment for terminal heart disease
- 90% are for idiopathic dilated cardiomyopathy and ischemic heart disease
- remaining 10% for congenital, valvular heart disease, cardiac tumor, life-threatening arrhythmias, and repeat transplant
what are goals of heart transplant?
- maintain coronary filling by optimizing DBP
- ensure optimal preload
- afterload reduction with the goal of increasing ejection fraction
- avoid pulmonary vasoconstriction: oxygenate, normocapnic, normal Vt, normal pH
- promote contractility: drugs, assist devices and balloon pumps
describe heart transplant monitoring
- a line
- CVL- CVP
- PA catheter pulled back to IJ prior to excision of heart
- TEE assesses volume, air, contractility, valve functioning and thrombus; also assesses wall motion of new heart
what is a good agent to induce cardiac transplant pts. with?
etomidate
-know for its cardiovascular stability, avoiding instability and preventing collapse on induction
why should induction of anesthesia and monitoring be rapid?
-keep the period of ischemia of the donor heart as short as possible to reduce ischemia reperfusion injury
what benefit does fentanyl have in cardiac anesthesia?
-prevent increases in systemic afterload during periods of intense surgical stimulation
what NMB was more commonly used in cardiac transplantation?
rocuronium d/t its fast-acting onset and intermediate effects
what can be done to help donor heart adapt to increased pulmonary artery pressure and pulmonary vascular resistance of recipient?
- use strategies to reduce pulmonary artery pressure and resistance and augment right ventricular contractility
- nitric oxide: vasodilates; effective to reduce pulmonary artery pressure but avoids systemic vasodilation and hypotension since inhaled
- dobutamine (5-10 mcg/kg/min), epi (0.05-0.3 mcg/kg/min), or dopamine (5-7.5 mcg/kg/min) provide inotropic support of right ventricle
