Transplant Anesthesia Flashcards
(171 cards)
1
Q
List the Canadian criteria for the neurological determination of death
A
- Established etiology capable of causing neurological death in the absence of reversible conditions capable of mimicking neurological death 2. Deep unresponsive coma 3. Absent brainstem reflexes as defined by absent gag and cough reflexes and bilateral absence of: a) motor responses excluding spinal reflexes b) corneal response c) pupillary response to light with pupils at mid size or greater d) vestibular-ocular responses 4. Absent respiratory effort based on apnea test. 5. Absent confounding factors a) umresuscitated shock b) hypothermia (<34) c) severe metabolic disorder capable of causing a potentially reversible come: glucose, electrolytes, inborn errors of metabolism, liver or renal dysfunction d) peripheral nerve or muscle dysfunction or neuromuscular blockade potentially accounting for unresponsiveness e) clinically significant drug intoxications (alcohol, barbiturates, sedatives, hypnotics)
2
Q
Describe an apnea test and thresholds. What is the ancillary test (ie. in case of COPD and attenuated resp drive)
A
Period of pre-oxygenation followed by 100% oxygen delivered via the trachea upon discontinuation from mechanical ventilation. Thresholds upon completion of the apnea test (all of): a) PaCO2 >= 60mmHg b) PaCO2 >=20mmHg rise above the pre-apnea test level c) pH <= 7.28 d) no respiratory effort throughout test Ancillary test: global absence of intracranial blood flow
3
Q
What are the systemic sequelae seen after brain death
A
1) hemodynamic instability (onset of brain death is associated with a transient period of hypotension with increased cardiac index and tissue perfusion. During this period, vasoactive drugs administered to increase blood pressure can cause rapid circulatory deterioration) 2) autonomic/catecholamine storm accompanies brain herniation 3) wide swings in hormone levels (adrenergic surges causing ischemia and repercussion injuries, followed by pituitary failure) 4) systemic inflammation 5) oxidant stress
4
Q
Describe a routine donor hormone replacement regimen
A
1) triiodothyronine (4-µg intravenous [IV] bolus, then 3 µg/hr); 2) methylprednisolone, 15 mg/kg intravenously every 24 hours; 3) desmopressin, 1 U then 0.5 to 4 U/hr to maintain systemic vascular resistance (SVR) at 800 to 1,200 dyne/s/cm 5 (and reduce the polyuria of diabetes insipidus). 4) Insulin infusion to maintain blood glucose 120 to 180 mg/dL
5
Q
Cardiac cath is requested for which heart donors
A
male donors >45 years old females >50 years old young donors with significant personal or family history of coronary artery disease.
6
Q
What additional donor criteria are requested for pHTN recipients
A
younger donors short ischemic time low donor inotrope requirement oversized organs are preferred.
7
Q
What criteria must all donor hearts meet
A
Human leukocyte antigen (HLA) typing ABO blood group compatibility The donor heart size should be within 20% to 30% of the recipient’s heart size.
8
Q
What are the targets to maintain euvolemia during procurement. Goals of fluid therapy?
A
1) CVP 6-12mmHg 2) Pulmonary capillary wedge pressure <12mmHg 3) Avoid HES 4) Minimize the use of pressers
9
Q
What are the blood and electrolyte targets during procurement?
A
1) Serum sodium levels <155mmol/L 2) Hct > 30% with pRBCs 3) FFP to maintain INR <1.5
10
Q
What are strategies to maximize donor lung function?
A
1) bronchoscopy to rule out major pathology 2) Low CVP 3) diuresis prior to procurement 4) glucocorticoids 5) prostaglandin E1 to improve circulation of preservation solution
11
Q
What are the ideal lung donor characteristics?
A
Age <55 years ABO compatibility Clear chest radiograph PaO >300 on FiO2 1, PEEP 5 cm H 2 O Tobacco history <20 pack-years Absence of chest trauma No evidence of aspiration or sepsis Negative sputum Gram stain Absence of purulent secretions at bronchoscopy
12
Q
What donor characteristics are associated with poor outcome?
A
1) Advanced donor age (>55 years) together with 2) long ischemic time (>6 hours) are associated with poor transplant outcomes 3) poor concordance of height, lung capacity
13
Q
DCD (deceased after cardiac death) account for what percentage of organ transplants?
A
10.6%
14
Q
What are the DCD criteria?
A
1) unresponsiveness - often have severe whole-brain dysfunction but have electrical activity in the brain 2) apnea 3) permanent cessation of circulation and respiration (arterial monitoring showing pulse pressure of zero, or Doppler showing no flow) (The ACCCM argues that no less than 2 minutes is acceptable and no more than 5 minutes is necessary when determining death for potential DCD. )
15
Q
What is a routine fluid load for living kidney donors?
A
A reasonable fluid protocol is to administer crystalloid at 10 mL/kg/ hr above calculated losses and to maintain urine output at about 100 mL/hr. Fluid loading overnight before surgery (vs. fluid administration starting with surgery) is associated with better creatinine clearance during the procedure, but this advantage is lost by postoperative day 2.
16
Q
What is concerning regarding post-op pain management in living kidney donors?
A
1/3 have chronic pain
17
Q
Regarding living liver donors, which procedure is most complex?
A
Left lateral segmentectomy (II and III) is used when adults are donating to children and are usually well tolerated. Right hepatectomy is required for adult-to-adult liver transplantation and is a major operation with significant risk. Complication rate 30%, morality of 0.2-0.5%.
18
Q
The residual liver volume of the donor must be ____ of original volume to prevent “small for size” syndrome in the donor.
A
>35%
19
Q
What are the complications of right hepatectomy donation?
A
air embolism, atelectasis, pneumonia, and biliary tract damage
20
Q
What is the main intraoperative challenge for living liver donors?
A
Large liver resections may require virtually complete hepatic venous exclusion (cross-clamping of the hepatic pedicle usually without cava clamping). Not unexpectedly, venous return falls significantly because patients are healthy and without collaterals. But fluid boluses increase CVP which can increase bleeding. If vasopressors are needed, use vasopressin or levo.
21
Q
What are the postoperative challenges after living liver donation?
A
- Pain control: INR peaks on POD1-3 when catheter would be removed. 2. Hypophosphatemia: Due to excessive loss in urine. Treat with sodium phosphate infusions to maintain phosphate levels 3.5-5.4mg/dL. 3. Elevated liver enzymes: typically return to normal in 3 months
22
Q
What are the criteria for living lung donation?
A
Member of recipient’s extended family Age 18–55 years No prior thoracic surgery on donor side Good general health Taller than recipient preferred ABO compatible FVC and FEV 1 >85% predicted PO >80 mm Hg on room air No chronic viral diseases Normal electrocardiogram and echocardiogram Normal stress test in donors older than 40 years old
23
Q
Why is immunosuppression a delicate balance?
A
Immunosuppressed patients who are undertreated risk rejection; overimmunosuppression can be toxic, especially to the kidneys.
24
Q
What are the major risks of immunosuppression?
A
CNS: lower seizure threshold CV: DM, HTN, hyperlipidemia, atherosclerosis Renal: decreased eGFR, hyperkalemia, hypomagnesemia Heamtological: increased risk of infection and malignancy, pancytopenia Endocrine: Osteoperosis, poor wound healing
25
What are the common calcineurin inhibitors?
cyclosporine, tacrolimus
26
How do CIs work?
Inhibition of calcineurin, among other effects, modifies NFAT (nuclear factor of activated T cells) and frees nuclear factor-κB to translocate to the nucleus, where it enhances transcription of T-cell interleukin-2 (IL-2). Via these signal transduction pathways, CNI inhibits T-lymphocyte activation, differentiation, and cytokine production.
27
What are the common side effects of CIs?
hypertension (often requiring therapy), hyperlipidemia, ischemic vascular disease, diabetes, nephrotoxicity. Drug specific: Cyclosporine - acute nephropathy, prolongs pancuronium Tacrolimus - Polyneuropathy and encephalopathy, induces P4503A4
28
What is the leading cause of death in kidney transplant recipients?
Ischemic heart disease
29
Does ESLD confer protection against CAD?
No
30
What are the common CI doses?
tacrolimus are 0.15 to 0.3 mg/kg/day given in two doses. To switch from oral to intravenous tacrolimus, a starting dose of about one-tenth the oral dose can be used. To switch from oral to intravenous dosing of cyclosporine, usually about one-third the oral dose is used.
31
What is the immunosuppressive mode of action of corticosteroids?
Corticosteroids disrupt expression of many cytokines in T cells, antigen-presenting cells, and macrophages.
32
Side effects of corticosteroids?
hypertension, diabetes, hyperlipidemia, weight gain (including Cushingoid features), and gastrointestinal ulceration
33
In what specific situation are corticosteroids typically withheld?
during liver transplantation in recipients with hepatitis C because of concern that they contribute to hepatitis C recurrence (little advantage).
34
What are the polyclonal and monoclonal antibodies used for immunosupression?
1. Antithymocyte globulin (ATG) - depletes T cells 2. OKT3 - blocking T cell function 3. Muromonab-CD3 (humanized-CD3) 4. IL-2 CD25 antagonists: basaliximab, daclizumab 5. CD80/CD86 antagonists: belatacept - block activation of T cells though the CD28 costimulatory pathway
35
What are the main classes of immunosuppressive drugs?
1. Calcineurin inhibitors 2. Corticosteroids 3. Polyclonal and monoclonal antibodies 4. Mammalain target of rapamycin inhibitors (mTOR) - sirolimus (diltiazem raises plasma levels) 5. Azathioprine - metabolized to 6-mercaptopurine, purine analog that incorporates into DNA during S phase of cell cycle. Therefore, antiproliferative. 6. Mycophenolate - inhibits purine synthesis 7. Mesenchymal stem cells - MSCs have pleiotropic effects on the immune response, including antiproliferative T-cell function. No adverse reactions. W
36
What should anesthesiologists know when administering ATG?
Acute and severe serum sickness is a rare side effect of ATG administration in patients with previous exposure to rabbits. Presents as jaw pain, and is treated by stopping the drug, plasmapheresis, and corticosteroids.
37
What should anesthesiologists know when administering OKT3?
Acute administration of OKT3 in awake patients (especially first administration) may result in generalized weakness, fever, chills, and some hypotension. More severe hypotension, bronchospasm, and pulmonary edema have been reported. Formulations of OKT3 may require syringe filtering before administration.
38
What should anesthesiologists know when administering IL-2 receptor antagonists?
GI side effects, pulmonary edema
39
What should anesthesiologists know when administering CD80/CD86 antagonists
Infusion reactions can include hypotension, but acute reactions are usually mild.
40
What should anesthesiologists know when administering mycophenolate?
Leukopenia, thrombocytopenia, red cell aplasia, teratogenic
41
What is the most common cause of graft loss after corneal transplant?
rejection of corneal allografts
42
What are the most common diagnoses of patients on the renal transplant waiting list?
Type 2 diabetes 30% Hypertensive nephrosclerosis 21.5% Glomerular disease 19.7% Polycystic kidney disease 6.6% Tubular/interstitial disease 5.0% Renovascular/other vascular 3.6% Congenital or metabolic disease 3.1% Neoplasm 0.3% Other
43
What are the considerations for renal transplant recipients?
1. high risk of CVS disease (stress test over 50) 2. anemia 3. hyperdynamic cardiac indices - higher PPF requirement 4. lung function - type I DM often present with reduced lung volumes and diffusing capacity 5. hypercoagulable states 6. cancer screen (mammography, pap smear, colonoscopy, PSA) 7. infection screen (dental evaluation and viral serology) 8. DM control 9. Dialysis before surgery 10. Complex serology typing 11. Uremic platelet dysfunction 12. Residual heparin from dialysis 13. All DM concerns 14. Altered drug metabolism - prolonged NMB - use cisatracurium,
44
What is the cold ischemia time for kidneys?
24-36hrs
45
What are the factors used in ECD kidney donors?
age, creatinine, stroke as cause of death, and hypertension
46
What are the serology matching specifics for kidney transplantation?
Blood type O kidneys are allocated to type O recipients, and blood type B kidneys are transplanted only in B recipients, except in the case of zero antigen mismatched candidates. Zero mis- matched kidneys have the same HLA A, B, and DR antigens.
47
Where are donated kidneys placed in the recipient?
Right iliac fossa or retroperitoneal space
48
What is the main operative consideration in renal transplant surgery?
Maintenance of renal blood flow, accumulation of drug metabolites (morphine, meperidine, remifentanil), electrolyte balance (as grafted kidneys are defective in concentrating urine and reabsorbing sodium)
49
What is the typical hemodynamic goals in renal transplant surgery?
systolic pressure \>90 mm Hg, mean systemic pressure \>60 mm Hg, and CVP \>10 mm Hg. Usually attainable without pressers.
50
\_\_\_\_\_\_\_\_ is the crystalloid of choice for kidney transplantation, and it preserves acid–base balance and electrolytes when compared with Ringer’s lactate or normal saline.
Plasma-Lyte
51
In renal transplant, what is started with the first anastomosis?
Diuresis with mannitol and furosemide
52
How is blood sugar important in renal transplant?
glucose \>160 mg/dL (8.9) as a risk factor for acute perioperative renal dysfunction, likely associated with more ischemia-reperfusion injury. Target is 80-110 (4.4 - 6.1)
53
The selec- tive DA1 agonist _________ is used to preserve renal function during kidney transplantation in some centers and is a superior renal protectant, although not extensively studied.
fenoldopam
54
How long does renal transplant usually take?
3hrs
55
What are the common postoperative complications after renal transplantation?
ureteral obstruction and fistulae, vascular thromboses, lym- phoceles, wound complications, and bleeding.
56
How are liver recipients prioritized for transplantation?
Patients with acute liver failure are given priority for donor livers, then the patients with the highest MELD score and compatible blood group are next. MELD Score = 0.957 × Log e (creatinine in mg/dL) + 0.378 × Log e (total bilirubin in mg/dL) + 1.12 × Log e (INR) + 0.643
57
How important is creatinine in liver disease?
Serum creatinine levels are not extremely useful in capturing renal function in patients with liver disease. Even a small increase in serum creatinine in these patients suggests significant renal dysfunction.
58
List the complications of end stage liver disease
Central Nervous System Encephalopathy (confusion to coma) Pulmonary Respiratory alkalosis Pulmonary hypertension Cardiovascular : Hyperdynamic circulation Reduced systemic vascular resistance High cardiac index Increased mixed venous O2 sat Diastolic dysfunction Prolonged QT interval Blunted responses to inotropes Blunted responses to vasopressors Diabetes Gastrointestinal Gastrointestinal bleeding from varices Ascites Delayed gastric emptying Hematologic Decreased synthesis of clotting factors Hypersplenism (pancytopenia) Impaired fibrinolytic mechanisms Renal Hepatorenal syndrome Hyponatremia Endocrine Glucose intolerance Osteoporosis Nutritional/metabolic Other Poor skin integrity; pruritus Increased volume of distribution for drugs Decreased citrate metabolism
59
Why is TEE particularly good for HOCM?
PA capillary wedge pressure does not accurately reflect left ventricular (LV) volume in this population.
60
What are the criteria for diagnosing porto-pulmonary hypertension?
(a) setting of liver disease (b) mean positive airway pressure ≥25 mm Hg, pulmonary vascular resistance (PVR) \>240 dyne/s/cm 5 , and PA occlusion pressure ≤12 mm Hg.
61
How is porto-pulmonary hypertension managed?
1. Echo - Systolic PA pressure estimates are made by capturing the maximum velocity of regurgitant flow across the tricuspid valve, and this velocity is used in the Bernoulli equation for the pressure gradient between the right ventricle and the right atrium (∆P = 4V x 10^4 ). If moderate to severe pulmonary hyper- tension (estimated systolic PA pressure \>50 mm Hg) is suggested, right heart catheterization is needed for direct pressure mea- surements. 2. Epoprostenol, Inhaled iloprost, Sildenafil, inhaled NO
62
PA pressure ____ mm Hg is an absolute contraindication to liver transplantation.
over 50
63
What spirometry pattern is seen in ESLD?
Reduced DLCO
64
What is the definition of hepatopulmonary syndrome?
HPS, a widened alveolar–arterial gradient in room air due to liver disease
65
How can a bubble study identify the location of shunts?
The microbubbles act as a contrast, and if intracardiac shunts are present, they appear within three heart beats after injection in the left ventricle. The later appearance of bubbles suggests intrapulmonary shunting.
66
List the intraoperative considerations for liver transplantation
1. RSI as gastroparesis is common, + abdominal pressure from ascites 2. Lines: 2 arterial catheters (left radial and right femoral), PA catheter, continuous TEE, 2 large bore catheters, VVB bypass lines at select centres 3. Rapid infuser with ability to deliver 500ml/min 4. Cross match 10U RBC, 10 units FFP 5. Dissection: correction of coagulopathies and maintenance of intravascular volume for renal protection.
67
What are the 3 phases of liver transplantation?
1. Dissection - blood loss may be high 2. Anhepatic - liver is functionally excluded from circulation, Involves clamping of IVC above and below, as well as portal vein and hepatic artery. Venous return falls 50-60%, causing hypotension. VVB can be used to increase venous return. 3. Neohepatic - marked by reperfusion of the graft, and represents the most treacherous time.
68
Is INR reliable predictor of bleeding in liver transplant? What is the INR target?
Although standard laboratory coagulation studies do not predict bleeding well, they are still the best tests available in real time in the OR. For this reason, FFP is used to maintain INR ≤1.5.
69
What are the principles of coagulation management in these patients?
1. FFP to keep INR \<1.5 2. CaCl2 infusion to prevent ionized hypocalcemia with citrate load (citrate typically metabolized by liver) 3. Fibrinogen \> 150mg/dl (normal is 150-400) with cryp 4. Platelets over 50,000 BUT platelet transfusion is detrimental to graft and patient survival 5. Both bleeding and hypercoagulable factors in play 6. Need a measure of whole blood clotting, like TEG (normal clotting with INR and low fibrinogen and platelets = hypercoagulable state, avoid procoagulant drugs) 7. Fibrinolysis acutely worsens immediately after reperfusion to varying degrees, depending largely on the amount of tissue plasminogen activator released from the graft 8. ε-aminocaproic acid (EACA; 5 g load and 1 g/hr infusion) or TXA to support hemostasis during surgery is useful in most coagulopathic patients, re-dose after reperfusion
70
What are the factors that affect coagulation in liver transplant?
Promote bleeding 1. poor clotting factor synthesis 2. renal failure 3. infection 4. endothelial dysfunction, 5. high portal pressures Promote coagulability 6. superimposed hypercoagulable state (ie. APLA) 7. Elevate vWF, FVIII 8. Low ADAMT-13, antithrombin, protein C, plasminogen
71
What is the common coagulation profile of a liver failure patient with impaired synthetic function?
thrombocytopenia, and hypofibrinogenemia, whole-blood clotting is delayed.
72
How do you treat PE during liver transplantation?
If diagnosed promptly, low-dose tissue plasminogen activator (0.5 to 4 mg) into the CVP port of a pulmonary artery catheter (PAC) can lyse the clot quickly
73
What is hepatorenal syndrome?
Hepatorenal syndrome (HRS) is a functional renal disorder associated with liver disease, categorized as: a) type 1 (acute severe decompensation, creatinine \>2.5 mg/dL), which is usually fatal b) type 2 (chronic, moderate renal failure with creatinine \>1.5 and glomerular filtration rate \<40 mL/min). HRS in general is the diagnosis of renal failure if the patient has ascites, is not in shock, has not been exposed to nephrotoxic drugs, has no parenchymal renal disease, has a creatinine level \>1.5 mg/ dL, and does not improve after 2 days of diuretic withdrawal and albumin therapy (1 g/kg/day up to 100 g/day).135
74
What is the dose of albumin to be given when draining large volume ascites?
6 to 8 g/L of ascites drained
75
What treatments can be used for HRS?
The most important consideration for patients with HRS is to ensure adequate volume replacement before instituting diuresis in the OR. Terlipressin (in Europe) and norepinephrine may be useful for HRS because they relieve splanchnic vasodilatation. The α1-agonist midodrine is useful for improving renal function in some patients.
76
What are the complications of VVB?
arm lymphedema, air embolism, and vascular injury, and its benefit is limited when anhepatic times are short.
77
What techniques can be used to prevent the need for caval clamping in the anhepatic phase?
Piggyback technique
78
What are the anesthetic considerations during reperfusion of the new liver?
1. Caval clamps removed and anastomoses checked 2. Caval reperfusion is usually well tolerated re: BP, but portal vein reperfusion causes hypotension and bradycardia. Can be prevented by flushing before reperfusion. 3. Sodium bicarbonate just before unclamping (25 to 50 mEq) to meet the acid load from the graft. For particularly prolonged acidosis tris(hydroxymethyl)aminomethane (THAM) infusion is useful. 4, 500 to 1,000 mg of CaCl2 precisely at the time of portal reperfusion to counteract the effects of potassium on the heart. 5, Monitor ECG for hyperkalemic changes, repeat Ca is changes seen 6. Lidocaine, atropine, and norepinephrine are available at the time of reperfusion in case of ventricular dysrhythmias, bradyarrhythmias, and severe hypotension. 7. Hepatic artery unclamping, typically uncomplicated
79
What are the physiological changes seen during the neohepatic period?
1. Calcium no longer required as graft metabolic function begins, even with rapid FFP infusion 2. @30 mins, base deficit improves with graft metabolism of citrate and lactate. Bile production begins. 3. @1hr, CO decreases (after an acute increase after portal reperfusion) as SVR increases with graft metabolism of vasoactive substances unleashed at reperfusion. 4, Renal function improves (graft metabolism of renal vasoconstrictors) 5. Biliary anastomoses are completed and surgical bleeding treated
80
What are the major classes of ECD liver donors?
advanced age, steatosis, DCD, split grafts, extended hospital stay LIMIT COLD ISCHEMIA TIME
81
What is the most common indication for pediatric liver transplantation?
Biliary atresia (43%) Inherited metabolic disease (13%)
82
Biliary atresia is associated with which other congenital defects?
ASD, situs inversus
83
What are some considerations for pediatric liver transplantation?
1. Access - radial artery catheter and at least one large (18-g) peripheral intravenous line are placed after induction of anesthesia. Surgeons may place tunneled central lines before incision. 2. Children with previous Kasai operations for biliary atresia may have massive bleeding during dissection because of adhesions. 3. Small children receiving large grafts may have respiratory compromise with abdominal closure. 4. Hepatic artery thrombosis is a more common complication in children than adults, some centers choose to have the INR at the end of surgery in the 1.8 to 2 range; postoperative aspirin and alprostadil are often used to prevent HAT. If flow is inadequate (by poor Doppler signals) in the artery after anastomosis, intraoperative reanastomosis or a new anastomosis under aortic cross clamp may be required acutely.
84
What are the main anesthetic considerations for both adults and children with acute liver failure (ALF)?
protection of the brain and treating cerebral edema
85
What is the role of ICP monitoring in ALF?
ICP monitoring is useful in managing these patients but risks intracranial bleeding; nonetheless its use is advocated by the US Acute Liver Failure Study Group. Useful alternative is transcranial Doppler monitoring, or bispectral index.
86
What is the target plasma osmolality when giving mannitol for ICP?
310 mOsm/L
87
Which vapour is best suited for ALF?
Trick question. Vasodilating anesthetics, including all inhaled agents, should be avoided, especially without ICP monitoring.
88
What is the best antihypertensive to use in ALF?
Labetalol does not cause significant cerebral vasodilation in these patients.
89
At what point intraoperative point is the ALF patient most at risk?
Reperfusion is often accompanied by acute cerebral vasodilatation.
90
T/F - The majority of pancreas transplants are done as simultaneous pancreas and kidney transplants from a single deceased donor.
T - 75% are done this way due to historical better long term survival. However, with proper donor selection and aggressive attention to targeted antibiotic coverage, better graft survival rates after isolated pancreas transplant outcomes have recently been reported.
91
The preoperative assessment of pancreas transplant recipients focuses on \_\_\_\_\_\_\_\_\_\_\_\_\_.
the end-organ complications of type 1 diabetes
92
The major difference between pancreas transplantation and other procedures is \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
strict attention to control of blood glucose is indicated to protect newly transplanted β cells from hyperglycemic damage. Once blood glucose levels are controlled (\<150 mg/dL), intravenous 5% dextrose (about 100 mL/hr) should also be infused as the insulin infusion is continued.
93
What is the make anesthetic consideration for isolated islet transplantation?
easier. Islets are generally infused into the portal circulation; acute portal hypertension may result from the infusion.
94
What are the indications for small bowel transplantation?
1. impending liver failure in patients with intestinal failure (or short-gut syndromes requiring total parenteral nutrition [TPN]), 2. frequent severe dehydration in patients with intestinal failure 3. severe complications of central lines for TPN (sepsis, thrombosis of central veins). Patients who develop liver failure from TPN for intestinal failure are candidates for combined liver-intestine transplantation. In general, intestinal transplantation is usually performed only in patients with life-threatening complications of the intestinal failure, mostly in children, but increasingly in adult recipients. For anesthesiologists, a major hurdle for these
95
What are the main anesthetic considerations for small bowel transplants?
Common complications of intestinal failure include dehydration and electrolyte abnormalities, gastric acid hypersecretion, pancreatic insufficiency, bone disease, and TPN-induced liver failure. Check electrolytes frequently. 2. Like reperfusion of liver grafts, intestinal graft reperfusion is associated with an acute release of acid and potassium from the graft. Anticipatory bicarbonate and CaCl2 administration are used to counteract the effects of acid and potassium on the heart. 3.After reperfusion, coagulopathy may worsen, and is usually managed by reassessment of INR, fibrinogen and platelet counts, and correction with blood products.
96
What are the most common indications for lung transplant?
chronic obstructive pulmonary disease (35%), idiopathic pulmonary fibrosis (23%), cystic fibrosis (CF, 17%), and α1-antitrypsin deficiency (6%).
97
Lung recipient selection guide (review)
(to be added)
98
What are the surgical options for lung transplantation?
single-lung transplant, en bloc double, sequential double, and heart–lung transplantation.
99
Compared to single lung transplants, double lung transplants have shown:
improved 1-year survival
100
Double-lung transplantation is most commonly used in patients with \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.
1) pulmonary vascular disease (native lung pulmonary vascular disease would cause pHTN in new lung). 2) CF (soiling) 3) anytime a single-lung transplantation would allow a continuing pathologic process to place either the native or transplanted lung in jeopardy. 4. Emphysema would cause airtrapping in old lung
101
when should patients be considered for lung transplant?
if they exhibit poor pulmonary function despite maximal medical therapy
102
What are routine evaluation for lung recipients?
1. screened for malignancy (mammography, Pap test, and colonoscopy) 2. PFT 3. left and right heart catheterization 4. transthoracic echocardiography Lung trans- plantation is not advocated for acute disease processes, such as acute respiratory distress syndrome
103
List the pre-op anesthetic considerations for lung transplants
1. It is critical to confirm ABO compatibility of donor and recipient prior to surgery. 2. Urgent surgery = likely full stomach 3. Minimal pulmonary reserve, and sedation must be given carefully under monitored conditions. 4. Central access 5. PAC 6. Thoracic epidural catheter - controversial but thought to be safe even in full CPB
104
List the intra-op anesthetic considerations for lung transplants
1, chronically intravascularly volume depleted 2. chronic pHTN 3. hypotension and decreased cardiac output on induction 4. awareness with restricted anesthetic (BIS) 5. fluid restriction is ben- eficial for postoperative management (CVP \> 7, PAC or doppler) 6. prolonged intubation - no fast tracking required 7. Nitrous oxide is rarely used because it may exacerbate bullous emphysematous disease, pulmonary hypertension, or intraoperative hypoxemia. 8. Lung isolation 9. Lung protective ventilation 10. Risk of pHTN or RV dysfunction during single lung ventilation, may require inhaled NO 11. Hypoxemia during single lung ventilation 12. Inability to ventilate, oxygenate, or maintain adequate RV function is an indication for CPB. 13. Change to single lumen at case end
105
What are the advantages of double lumen tubes over bronchial blockers?
allows better suctioning of secretions improved deflation of the operative lung during dissection application of continuous positive airway pressure to the operative lung if indicated less likely dislodged by surgical manipulation better isolation of the RUL no repositioning required in sequential procedure
106
What are the lung protective strategies used during lung isolation?
small tidal volumes (6 mL/kg) oxygenation techniques, using PEEP and the lowest acceptable fraction of inspired oxygen (FiO 2 ) settings.
107
What determines the operative side?
Determination of operative side is based on preoperative ventilation–perfusion studies and prior thoracic surgeries, poorer lung replaced
108
What is the sequence of re-anastamosis in lung transplant?
sequentially anastomose the atrial/pulmonary vein patch, bronchus, and pulmonary artery.
109
What is the common role of the anesthetist after lung reperfusion?
assess the bronchial anastomosis using fiberoptic bronchoscopy perform bronchopulmonary toilet on the transplanted lung if necessary (removal of blood, secretions) TEE to assess pulmonary venous drainage
110
\_\_\_\_\_\_\_\_\_\_ a low-molecular-weight dextran solution, improves early graft function and is now used widely for preservation during lung procurement.
Perfadex
111
What features should prevent changing from double to single lumen tube?
Significant oropharyngeal edema, high PEEP requirement, or need for differential lung ventilation `
112
Bilateral sequential transplant is now preferred over double because:
tracheal anastomosis is unnecessary and there is less surgical bleeding. (only drawback is longer ischemia time for second lung)
113
What are the common indications for lung transplantation in kids?
The most common diagnoses are CF, congenital heart disease, and primary pulmonary hypertension. Congenital heart disease is the most common indication in infants.
114
What % of CF kids receive a survival benefit from transplant?
1%
115
What are the 3 most common causes of acute graft lung failure?
acute rejection inadequate pulmonary venous drainage primary graft dysfunction (PGD).
116
What is the definition of primary graft dysfunction?
allograft dysfunction occurring within 72 hours of transplantation, graded on a scale of 0-3
117
What is the primary graft dysfunction rating scale signify?
Grade 0 means no PGD, the PaO2/FiO2 ratio is \>300, and no pulmonary infiltrates are present. Grade 1: PaO2/FIO2 \> 300 with infiltrates Grade 2: PaO2/FIO2 200-300 Grade 3: Grade 3 is defined as PaO2/FiO2 \<200 with radiographic infiltrates consistent with pulmonary edema, associated with increased 30 day mortality.
118
What factors likely contribute to lung PGD?
prolonged organ ischemia time with ischemia–reperfusion injury advanced donor age pulmonary hypertension in the recipient, and the use of CPB Non-contributors: anesthetic management, transfusion
119
What features predict high transfusion requirements during lung transplant?
that patients undergoing double lung transplants procedures with CPB Eisenmenger syndrome CF
120
What is one potential option for severe, life threatening PGD?
ECMO
121
What are the main purposed of using inhaled NO?
decrease pulmonary vascular resistance improve oxygenation relieve R heart strain
122
What inactivates inhaled NO?
reacting with heme to produce methemoglobin.
123
Why does NO improve ventilation?
Because iNO is preferentially delivered to ventilated areas, vascular relaxation in these areas leads to improved blood flow and hence, improvements in ventilation–perfusion matching and oxygenation.
124
Why doesn't NO cause systemic vasodilatation and hypotension?
Rapid inactivation of iNO in the pulmonary vasculature prevents its systemic distribution and systemic vasodilatation and hypotension.
125
Besides ventilation and CV, what other benefits does NO have?
immunomodulatory antimicrobial activities attenuates platelet aggregation and adhesion decreased pulmonary vascular resistance decrease inflammatory response impedes microbial growth
126
What are the risks of inhaled NO?
methemoglobinemia NO-metabolite–related lung injury and decreased sensitivity of exhaled NO monitoring as a diagnostic tool for acute lung rejection.
127
[T/F] Clinical trial of 30 patients undergoing double-lung transplant at an institution with high usage of CPB showed no benefit of prophylactic iNO in prevention of pulmonary edema
T
128
What is the least common thoracic transplant procedure?
heart-lung, largely replaced by bilateral sequential.
129
What is the survival data after heart transplant?
1-year survival is approaching 90% and 7-year survival 75%.
130
What are the common indications for heart transplant?
nonischemic cardiomyopathy 53.3%, ischemic cardiomyopathy 37.7%, congenital heart disease 2.9%, valvular cardiomyopathy 2.7%, retransplantation 2.6%, miscellaneous 0.8%.194
131
What are the nonsurgical therapies for heart failure?
1. neurohormonal inhibition: ACEI, B-blocker 2. cardiac resynchronization therapy - reduced hospitalization and death rate in advanced, chronic HF patients
132
What are the surgical therapies for heart failure?
1. Surgical ventricular restoration is a procedure designed to remodel LV function through restoration of ventricular geometry in patients with a dilated LV. Purse string the scarred myocardium. 2. Ventricular assist devices 3. Transplant
133
Stages in the development of heart failure with recommended therapy by stage
(to be added)
134
What are the indications for LVAD?
patients who cannot be weaned from inotropic therapy or restored to New York Heart Association class III despite medical therapy optimization or for those who are not transplant candidates.
135
What are the 3 applications for LVAD?
VADs have three main clinical applications: bridge to trans- plant (BTT), bridge to recovery (BTR), and DT.
136
What is the benefit of LVAD over medical management?
(REMATCH) clinical trial reported an 81% improvement in sur- vival and improved quality of life of terminally ill HF patients with implanted heart pumps versus optimal medical management.
137
What are the criteria for LVAD implantation? (5)
Criteria for VAD implantation are essentially the same as the definition of cardiogenic shock: Cardiac index \<2 L/min, SVR \>2,100 dyne/s/cm 5 pulmonary capillary wedge \>20 mm Hg systemic hypotension \<80 mm Hg urine output \<20 mL/hr with metabolic acidosis.
138
What are the contraindications for LVAD implantation?
irreversible end-organ failure advanced pulmonary disease unrelated to cardiac function sepsis metastatic cancer.
139
Describe the generations of LVADs (3)
1) The first generation generally consists of pumps such as the Thoratec VAD which provide pulsatile flow. 2) Second-genera- tion VADs are smaller devices making use of electromechanical impellers to drive blood forward (Heartmate, Jarvik) 3) bearingless, magnetically, and/or hydrodynamically suspended impellers that minimize heat generation and improve durability. VADs vary in significant ways according to location of device (intra-, extra- or paracorporeal), the source of driving power (pneumatic or electric), the level of anticoagulation required (none, aspirin, warfarin), flow range, filling pattern (fill- to-empty or various other modes), and power source (battery or alternating current).
140
Where are VADs typically positioned?
VADs are usually positioned in parallel with the circulation. LVADs are positioned with the inflow cannula in either the left atrium or left ventricle and drains to the pump. The outflow cannula returns blood to the patient via an anastomosis with the ascending aorta.
141
What affects LVAD pump flow?
1) intravascular volume 2) afterload Therefore, failure to correct hypovolemia and increased afterload will result in decreased LVAD flow and hypotension because of low functional cardiac output.
142
What are the prerequisites to LVAD utilisation?
blood products (packed red blood cells, FFP, and platelets) invasive monitoring is required: arterial line, large-bore introducer with PAC, or a second central venous catheter in the setting of difficult venous access. CPB TEE
143
What structural defects need to be ruled out before LVAD insertion?
Intracardiac shunts can cause hypoxemia post CPB Aortic insufficiency RV function Cardiac thrombi Aortic atheroma
144
What are the means of confirming proper LVAD function with TEE?
LV decompression, aortic valve closure dur- ing LVAD systole, and outlet cannula presence in the aorta with appropriate flow
145
What are the risks of LVAD?
acquired vWF deficiency cerebral hyper perfusion neurological dysfunction
146
What is the most common indication for heart transplant;?
non-ischemic cardiomyopathy (since 2005)
147
Are heart transplants done at the national level?
No, ischemic time limited to 4-5 hrs
148
What are the contraindications to heart transplantation?
1) irreversible pulmonary hypertension (PVR \>6 Wood units/m 2 and high transpulmonary gradient \>15 mm Hg) 2) Severe recipient hepatic, renal, or pulmonary disease
149
Indications for heart transplant?
patients requiring continuous mechani- cal or inotropic support, peak O 2 uptake \<14 mL/kg/min, LVEF \<20%, inoperable congenital heart disease, intractable malig- nant arrhythmias, and pulmonary vascular resistance \<2 Wood units.
150
What are the 4 anastomoses needed for HT?
1) the right and left atrial anastomoses 2) the end-to-end aortic and pulmonary anastomoses.
151
What are the two main techniques for heart transplantation? Whats the difference?
1) Biatrial technique 2) Bicaval - better preserves atrial geometry, tricuspid annu- lus shape, and right ventricular function, with less tricuspid and mitral regurgitation and less conduction disturbances.
152
What are the two approaches to HT?
1) orthotopic approach, in which the donor heart is placed in the normal anatomic location. 2) the heterotopic approach is an infrequently utilized technique, indicated in patients with significant pulmo- nary hypertension to preserve the donor RV and in significant size mismatch, which can complicate pediatric transplantation. The donor heart is implanted in the lower right thorax, resulting in two parallel circulations. Native RV supports right circulation, and donor RV supports left (systemic) circulation.
153
What issues need special attention when evaluating the HT recipient?
1) Nothing by mouth status 2) Level of cardiovascular support (inotropic infusions, chronic medications for heart failure, presence of LVAD), 3) Presence of hemodynamic monitoring lines or antiarrhythmic devices, such as pacemaker, CRT device, or defibrillator. 4) Antiarrhythmic devices 5) Meds - ie. ACEI, anticoagulants
154
Why do surgeons prefer you not to touch the RIJ during HT surgery?
some surgeons prefer to leave the right IJV for future endomyocardial biopsies
155
Effect of denervation on cardiac physiology
(to be added)
156
What may you see on ECG in HT patients?
Residual native atrial tissue may continue to have elec- trical activity, seen clinically as two P waves on ECG. The native P wave has no physiologic effects on the donor heart.
157
What is the most common complication encountered during weaning of CPB in HT?
RV failure, high PA pressures over 30. Treat - avoid hypoxia, hypercarbia, acidosis 2) pressors 3) iNO or inhaled prostacyclin
158
What pressor is used most frequently for the denervated heart?
Isoproterenol is used frequently for its direct effects on cardiac β-receptors to increase graft heart rate. Temporary epicardial pacing is sometimes useful until iso- proterenol has had adequate time to reach maximal effect.
159
Most common diagnosis in paediatric heart transplant?
congenital heart disease or idiopathic/viral cardiomyopathy in 75% of these patients.
160
Explain the dynamics of hyper acute rejection in paediatric HT?
Hyperacute rejection does not occur because of the immaturity of the immune system and absence of preformed antibodies to various antigens, including blood group antigens.
161
What are the main issues for composite tissue transplantation?
1) regional okay 2) may be heparinized 3) reperfusion events 4) intense immunosuppression, due to high antigenicity of skin 5) at least one center uses donor marrow infusions in an effort to induce tolerance to the allograft.
162
What are the main issues for renal transplant recipients for future surgeries?
1) the level of renal dysfunction will often determine the choice of drugs, particularly neuromuscular blockers, and dose modification of drugs is dependent on renal excretion, such as antibiotics. 2) A major consideration for renal transplant recipients is maintenance of renal perfusion with adequate volume replacement. Thus, CVP monitoring is useful for preventing prerenal damage to transplanted kidneys, but CVP lines must be placed using strict aseptic technique. 3) For all transplant recipients, antibiotic, antiviral, antifungal, and immune suppression regimens should be disrupted as little as possible in the perioperative period.\ 4) Avoid nasal intubation, introduces nasal flora
163
Drugs that may cause renal dysfunction when coadministered with calcineurin inhibitors
Amphotericin Cimetidine Ranitidine Melphalan Nonsteroidal anti- inflammatory drugs Cotrimoxazole Vancomycin Tobramycin Gentamicin
164
Drugs affecting cyclosporine or tacrolimus blood levels
165
How do the types of infection to which transplant recipients are susceptible change over time?
donor-derived and hospital-acquired infections predominating in the first posttransplant month. Infections acquired by transplant patients in months 2 to 6 versus later after transplantation are also distinct, and these patterns should guide surgical prophylaxis and perioperative diagnostic procedures.
166
Considerations for future surgery post lung transplant
1) For lung transplant recipients with a tracheal anastomosis, denervation has occurred below the level of the suture line, and the cough reflex is diminished or absent. 2) These patients are at increased risk of retained secretions and pneumonia and have an increased airway hyperreactivity and bronchospasm. 3) Because most lung transplants are now being done with bronchial instead of tracheal anastomoses, the risk of tracheal suture line stenosis or disruption with manipulation is markedly diminished.
167
What are the signs of infection or rejection in transplanted lungs?
1) Significant decreases in forced expiratory volume in 1 second, vital capacity and total lung capacity, and an obstructive pattern may indicate acute rejection. 2) Arterial blood gas in the presence of rejection will show an increased A–a (Alveolar–arterial) gradient from stable baseline gases, along with perihilar infiltration on CXR.
168
What does the denervated heart not respond to?
1) indirect acting agents, such as ephedrine and even dopamine 2) peripheral attempts to induce hemodynamic changes, such as carotid massage, Valsalva maneuver, or laryngoscopy.
169
How does the denervated heart respond to norepinephrine?
β-effects of epinephrine and norepinephrine are exaggerated in heart transplant recipients (vs. α-effects).
170
Why is GA better than RA for post HT surgeries?
Because the denervated heart does not reflexively compensate for hemodynamic changes induced by regional anesthetics, general anesthesia is usually preferred.
171
How does heart rejection present?
heart failure
