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History and Introduction
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The first successful kidney transplant, performed in the mid 1950s, was between identical twins.1 Transplantation between identical twins resulted in excellent long-term graft and patient survival. However, the growth of kidney transplantation began in earnest with the development of improved immunosuppressive agents, particularly cyclosporine in 1983. In the United States alone, approximately 16 830 kidney transplants were performed in 2009.2
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Organ Matching, Availability, and Allocation
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Kidney transplantation is now the preferred treatment for end-stage renal disease (ESRD) of almost any origin. There is evidence that patients may benefit from earlier transplantation even if the donor organ is not optimal because the high mortality of long-term dialysis favors the risk:benefit ratio toward transplantation.3,4 The 5-year survival of patients on chronic hemo- or peritoneal dialysis is only 30%. In contrast, the 5-year survival following transplantation for ESRD is 70%. Therefore, except in rare instances, transplantation should be performed in all patients with renal failure where it is technically feasible.5
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Several methods are used or being investigated to increase the number of kidneys available for transplantation (Table 59-1). Living kidney donation is becoming an important source of donor kidneys. Approximately 6388 patients received a transplant from a living donor in the Unites States in 2009.2 Recipients of living related kidney transplants generally suffer fewer episodes of acute and chronic rejection than those receiving cadaveric organs. Recipients also benefit because living related and unrelated transplantation is performed on an elective, nonemergent basis.6
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Voluntary organ donation from living related and unrelated donors has led to the establishment of "the living donor exchange."7 Living donors may ask the anesthesia provider about the risks associated with kidney donation. A recent study8 reported that short-term (90-d) mortality was significantly increased when compared to a matched cohort that did not undergo donor nephrectomy, but the difference disappeared over time and the long-term mortality was actually less in those that underwent donor nephrectomy (Fig. 59-1). The early mortality was greater for men, black individuals, and those with a history of hypertension. Obesity and age did not have an impact. The long-term survival may reflect their better preexisting health status that led to them being selected as living donors.
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Indications and Contraindications
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The most common causes of end-stage renal failure in adults are diabetes mellitus, systemic hypertension, glomerulonephritis, and polycystic kidney disease. In children and adolescents, the most common causes of ESRD are congenital malformations of the kidneys and urinary tract and focal segmental glomerulosclerosis.5
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Ideally, patients with progressive renal failure should receive a kidney transplant before they begin dialysis.5,9 Also, diabetic patients with marginal renal function who receive a pancreas transplant should receive a simultaneous kidney transplant because the immunosuppressive agents required for the pancreas transplant may cause further deterioration of renal function to the point of requiring dialysis.9
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There are a decreasing number of absolute and relative contraindications to renal transplantation: Many conditions that were thought to be contraindications to transplantation previously, such as HIV, hepatitis C, age over 65, and advanced congestive heart failure, are now considered as acceptable.10-13 Highly sensitized patients, T-cell positive cross-match, and ABO blood group–incompatible patients are now considered potential renal transplant candidates, albeit with an increased morbidity and mortality.14
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Although the indications for kidney transplantation have been expanded significantly, some individuals with ESRD are not good candidates for this procedure. Active infection, active drug abuse, complete thrombosis of the vena cava and iliac veins, and disseminated malignancies are among the contraindications to transplantation. Sensitization by previous failed transplants, blood transfusions, or pregnancy will require individual assessment because in some the graft survival would be too poor to transplant.15 Patients who have a history of noncompliance or mental retardation where it is unlikely that they will take their medications constitute relative contraindication to transplantation. However, patients with mental retardation can be transplanted successfully if they have a caregiver responsible for administering the medications.16
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The surgical procedure of kidney transplantation is straightforward. In adults and older children (>20 kg), the transplanted kidney is usually placed in the extraperitoneal iliac fossa via a curvilinear incision along the lateral margin of the rectus muscle approximately 8 to 10 in from just above the pubic bone to just above the umbilicus (Fig. 59-2). The common and external iliac arteries and veins are exposed retroperitoneally. The renal vein is anastomosed before the renal artery, and an end-to-side or end-to-end anastomosis may be performed depending on the anatomy of the vessels and depth of the renal pelvis. The renal artery is then anastomosed to the internal or external iliac artery. Occasionally, donors have multiple renal arteries, and several arterial anastomoses are required. Renal revascularization involves clamping of the iliac artery and vein. This can result in ischemia to the lower extremity for as long as 60 minutes. After the vascular anastomoses are completed the clamps are released in a staged fashion, resulting in perfusion of the kidney graft and lower extremities. The final stage of the operation involves reconstruction of the urinary drainage by anastomosing the donor ureter to the patient's bladder.
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In infants and small children (<20 kg), a transperitoneal approach is used. An incision from the xiphoid process to the pubis is made (see Fig. 59-2). The bowel is mobilized and the aorta and vena cava are exposed. The donor artery and vein are then anastomosed to the aorta and vena cava end to side. Once the vascular anastomoses are complete, the clamps are released, resulting in reperfusion of both lower extremities and the donor kidney. The urinary drainage is then reconstructed.17
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For living kidney donors, the laparoscopic and laparoscopy-assisted approach to nephrectomy is preferred due to a decreased need for pain medication, earlier discharge, and more rapid functional recovery.18 The left kidney is preferred due to implantation advantages associated with a longer renal vein. The patient is positioned in the left lateral position with elevated kidney rest. Positioning of the patient requires great care to prevent positioning-related injuries (see Chapter 27).
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Pretransplant Evaluation
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Patients undergoing kidney transplantation require a complete medical review and evaluation prior to surgery. (Preoperative evaluation of patients with renal disease is presented in Chapter 14; only brief comments that apply to transplantation will be provided here.) The evaluation is best done by the transplant surgery team prior to placing the patient on the transplant list. After the initial evaluation, cardiovascular surveillance is necessary. Frequency and type of surveillance, however, are a matter of discussion. In high-risk patients it may be prudent to do it annually or at least biannually.19
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Table 59-2 lists medical conditions related to ESRD.
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Half of all deaths after renal transplantation are cardiac related, and cardiac disease is the leading cause of death in the first year posttransplant.20 Besides severe coronary artery disease, sudden cardiac death of arrhythmic origin is also important.21
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Patients with diabetes, peripheral vascular disease, angina, or a longer duration of ESRD have a greater risk of mortality due to cardiovascular disease.20 However, what constitutes the optimal pretransplant evaluation is still debated. Exercise stress testing, myocardial perfusion studies such as dobutamine stress echocardiography and thallium scintigraphy, and cardiac computed tomography (CT) or cardiac magnetic resonance imaging (MRI) can be used. Coronary angiogram remains the gold standard with the ability to predict cardiac events.22 Data to strongly support preemptive myocardial revascularization in patients with stable coronary disease are lacking.
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Special Considerations in Patients with ESRD
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Due to a high incidence of cardiac disease, some centers recommend coronary angiography in patients with ESRD associated with diabetes if they are older than 45 years of age, have a smoking history, have a body mass index above 25, have had diabetes for more than 25 years, or have electrocardiographic signs of ischemia.23 Diabetic patients who have significant coronary disease with treatable lesions should have coronary artery surgery or an angioplasty prior to receiving a kidney transplant.23 Some diabetics have significant but diffuse coronary disease (identified by angiography) that cannot be treated surgically or by angioplasty. These patients may still benefit from combined kidney and pancreas transplantation instead of chronic dialysis, but they are at higher risk for perioperative cardiac events.24 Successful pancreas transplant in these patients slowed the progression of atherosclerotic lesions (mean segmental diameter loss 0.024 mm/y vs 0.044 mm/y) and caused regression of atherosclerotic lesions in 38% of patients with a functioning pancreas graft.
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Furthermore, diabetic patients can suffer from a host of comorbidities that affect anesthetic care, including autonomic neuropathy, gastroparesis, peripheral neuropathy, and peripheral vascular disease. The time of insulin administration is important to note in diabetic patients because it can influence the plan for perioperative glucose management. Diabetic patients should also be asked about symptoms of gastroparesis, such as heartburn, bloating, and explosive diarrhea, because they may be at risk for aspiration of gastric contents upon induction of general anesthesia. These patients will benefit from a nonparticulate antacid, such as sodium citrate or related compounds, prior to induction of general anesthesia. (See Chapter 13 for a detailed review of the preoperative assessment of diabetics.)
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Hypertension is another common cause of renal failure that affects multiple organ systems. Patient's usual blood pressure, years of hypertension, and the type and last dose of antihypertensive medications that the patient receives should be recorded. In general, patients should receive their usual blood pressure medications prior to surgery.25 However, angiotensin-system inhibitors administered immediately before operation have been associated with a greater incidence of hypotension upon induction of general anesthesia in hypertensive patients.26
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β-Blocker therapy should be continued in those receiving treatment preoperatively, and started in those with a positive stress test, according to the most recent ACC/AHA guidelines. The evidence also favors perioperative β-blockers in high-risk patients (more than 3 risk factors: high-risk surgery, ischemic heart disease, congestive heart failure (CHF), cerebrovascular disease, insulin-dependent diabetes mellitus, renal failure—creatinine >2.0 mg/dL).27 The use of β-blockers in low- and intermediate-risk patients is not supported by current available data.
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Sleep-Related Breathing Disorders
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An increasing number of patients with ESRD are being recognized to have sleep-related breathing disorders (SRBDs).28 Lee et al examined patients before and after kidney transplantation. Kidney transplantation was effective in improving sleep patterns and also improving the apnea/hypopnea index (Fig. 59-3). (See Chapter 11 for a more detailed discussion of sleep-related breathing disorders.)
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Several components of the physical examination deserve special consideration in the preanesthetic evaluation of the renal transplant patient. The evaluation of the airway is particularly important for diabetics. Patients with long-standing diabetes often develop stiff joints due to glycosylation of the connective tissue that results from elevated blood sugars. The inability to oppose the palms of the hands is 1 sign in a diabetic patient that stiff connective tissue may be present. Patients with stiff joints may be difficult to intubate and may require an awake, fiberoptic intubation.29
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The arms of patients on chronic hemodialysis should be examined for the presence of both functioning and nonfunctioning dialysis shunts and fistulas. Upper-extremity fistulas may clot during transplantation surgery from reduced blood flow during surgery or the perioperative elevation of clotting factors. Care must be taken in padding the upper extremity with a forearm fistula so that no restriction of blood flow in the fistula occurs. The blood flow through the fistula during surgery can be monitored by palpation or a Doppler device. The arm with a functioning fistula should not be used for blood pressure monitoring, venipuncture, or the placement of intravascular catheters because each such a maneuver may cause the fistula to thrombose.25 In the event of delayed graft function or even nonfunction following kidney transplantation, a functioning dialysis shunt is invaluable in the postoperative period.
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Assessment of Fluid Balance
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Fluid balance is often difficult to assess in patients on chronic dialysis. One method to help evaluate the volume status of a patient on chronic dialysis is to review the patient's body weight before and after dialysis. The weight of the patient at the completion of dialysis, the "dry" weight, can be determined and compared to the weight when the patient presents for surgery.17The type of dialysis, time of last dialysis, and frequency of dialysis are important to obtain as well.25 Depending on the type of dialysis and the interval since last dialysis, the patient is rarely euvolemic and usually arrives in the operating room either hyper- or hypovolemic. Significant hypotension upon induction of general anesthesia in recently hemodialyzed patients is therefore not uncommon.17 Anesthesia care providers must be prepared to rapidly replace the intravascular volume in these patients. Depending on the extent of hypovolemia, either intravenous normal saline or 5% albumin may be used to provide a more rapid and sustainable cardiovascular response.
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There are several laboratory tests that should be performed in all patients. Because electrolytes and blood glucose can change markedly over several days, particularly in patients on dialysis, most of these tests should be performed at or close to the time of operation. An electrocardiogram should be obtained in all patients at risk for cardiac disease, and the results compared to those of previous studies. The serum potassium may increase during surgery from the effects of drugs administered, blood transfusions, or from the infusion of hyperkalemic preservative solution from the new kidney. Therefore, surgery may have to be delayed and dialysis or other intervention performed if the patient is hyperkalemic (>6 mmol/L) preoperatively. Coagulation studies (international normalized ratio [INR], partial thromboplastin time [PTT], fibrinogen, platelet count) should be obtained if the patient has a prior history of bleeding or other evidence of a possible coagulopathy. Finally, the hemoglobin value should be determined and several units of blood made available preoperatively because patients with renal failure are often markedly anemic preoperatively.25 Fluid loading to increase central venous pressure in preparation for reperfusion and surgical blood loss may further decrease blood hemoglobin values and thus warrant intraoperative packed red cell transfusion.
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Induction and Maintenance of General Anesthesia
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The choice of induction agent depends on the overall health of the patient, the volume status of the patient, the presence of autonomic neuropathy, and the presence of cardiovascular or other disease. Relatively healthy renal transplant recipients tolerate induction of general anesthesia with propofol (2.0-3.0 mg/kg) or thiopental (2.5-3.0 mg/kg) without difficulty. However, etomidate (0.2 mg/kg) is better tolerated in hemodynamically compromised patients because it exerts minimal myocardial depression and preserves autonomic tone. This is particularly important in diabetic patients with autonomic neuropathy. Fentanyl (3-5 mcg/kg intravenously [IV]) can be administered during induction to blunt the hypertensive response to tracheal intubation. In patients who do not have a history of gastroparesis or acid reflux disease, intermediate-duration nondepolarizing muscle relaxants that do not depend on renal excretion for elimination, such as cis-atracurium (0.2 mg/kg), rocuronium (0.5 mg/kg), or vecuronium (0.1 mg/kg), can be administered to facilitate tracheal intubation.25
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In patients with gastroparesis or acid reflux disease, a rapid sequence induction, including Sellick maneuver to prevent regurgitation of gastric contents, should be performed. The depolarizing agent succinylcholine (1.5 mg/kg IV) has classically been used in patients without renal failure to provide rapid skeletal muscle relaxation for immediate tracheal intubation. However, the serum potassium can increase 0.6 mmol/L with its administration, so it should be used with caution, if at all, in patients with renal failure who have an elevated preoperative potassium level (>5.5 mmol/L). Many anesthesia providers therefore prefer to use nondepolarizing agents even if a rapid sequence induction is required. Rocuronium is useful for this purpose because at high doses (1.2 mg/kg) it has an onset of action of 60 to 90 seconds and does not require renal function for elimination.25
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The inhaled agents desflurane and isoflurane are both extremely useful for the maintenance of general anesthesia for kidney transplantation. Neither agent has nephrotoxic properties, and no deterioration of renal function has been noted with either agent in patients with or without renal disease.5 Nitrous oxide may be used along with the potent inhaled agent. It has minimal side effects, no renal toxicity, and rapid elimination. However, it is associated with increased nausea and vomiting in the postoperative period.30 As a result it may be used less frequently for these procedures in the future. Sevoflurane is rarely used for renal transplantation due to concerns of fluoride and compound A toxicity.31 Most human studies have not demonstrated deleterious effects of sevoflurane on the kidney.32 Many authors, however, feel that in the presence of other alternatives, there seems to be little reason to select sevoflurane for inhalation anesthesia in renal transplant patients. However, sevoflurane has been demonstrated to have anti-inflammatory and antinecrotic effects on renal tissue, which may be protective against ischemia-reperfusion injury.33 Overall, uncertainty remains regarding the use of sevoflurane in renal transplantation.
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During anesthesia care, opioids such as fentanyl (50-100 mcg/h) are often administered throughout the transplant procedure to reduce the amount of inhaled agent required and decrease the likelihood of the patient awakening in severe pain. The pharmacokinetics and pharmacodynamics of fentanyl, sufentanil, alfentanil, and remifentanil are not significantly altered by kidney disease, and all have been successfully used during renal transplantation.34
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Ongoing skeletal muscle relaxation can be provided with nondepolarizing muscle relaxants that do not depend on the kidney for elimination, such as cis-atracurium, rocuronium, or vecuronium. All 3 have been used successfully in patients with marginal or no renal function, and have minimal effects on the heart rate or blood pressure. Cis-atracurium is broken down in the plasma by Hoffman elimination, which does not depend on renal or hepatic function. Its duration of action is not prolonged in renal failure. Although the liver is the primary metabolic site for both rocuronium and vecuronium, the duration of blockade may be prolonged with these drugs if large doses are used, due to accumulation of metabolites that are excreted by the kidney.5,35 Pancuronium should not be used in kidney transplant recipients because it depends primarily on the kidney for elimination. If the new kidney does not function adequately initially, a prolonged neuromuscular block may result.5
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Blood glucose determinations should be made every hour in renal transplant recipients who have insulin-dependent diabetes mellitus. Evidence suggests that the incidence of wound infections can be reduced in diabetic patients if the blood sugar is tightly controlled.36 The extent of glucose lowering, however, is questionable. The NICE (Normoglycemia in Intensive Care Evaluation) study demonstrated a 2.5% increase in mortality for patients on intensive insulin therapy where blood glucose was kept in the 80 to 110 mg/dL range.37 Middle-ground target glucose of between 140 and 180 mg/dL is suggested at this time.38 Whenever the intraoperative blood sugar is between 90 and 110 gm/dL, a low-dose dextrose solution (D51/2 normal saline at 25 mL/h) should be administered concurrently throughout the procedure to provide for intraoperative nutrition and prevent hypoglycemia.39
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Emergence from General Anesthesia
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Following the operation, most patients can be extubated in the operating or recovery room when they are alert, strong, and able to maintain adequate ventilation. Rarely is postoperative ventilation required.
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Pain control can be achieved with neuraxial anesthesia, and the successful use of combined spinal-epidural anesthesia for both surgical anesthesia and postoperative pain relief has been described.40 However, although rare, there is a small risk of an epidural hematoma.
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Because most graft recipients receive heparin intraoperatively, and some in the postoperative period, intravenous opioids such as fentanyl, morphine, or hydromorphone are usually used for postoperative analgesia. These drugs may also be used for patient-controlled analgesia following discharge from the recovery room.5
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All opioids must be used cautiously in renal transplant recipients, particularly if the graft is not functioning properly. For example, a metabolite of morphine, morphine-6-B-glucuronide, has opioid agonist activity and is excreted by the kidneys. It can accumulate in renal failure and cause respiratory depression with long-term use. The metabolism of hydromorphone produces a neuroexcitatory compound that can accumulate in renal failure. However, hydromorphone has been used extensively in renal failure patients with no adverse effects. In contrast, a metabolite of meperidine (Demerol), normeperidine, can accumulate in significant amounts in patients with renal failure, and this compound can cause seizures. Therefore, meperidine should not be used for postoperative analgesia in renal transplant recipients.34
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Patients undergoing renal transplantation usually benefit from central venous access. It provides convenient vascular access to obtain blood samples and for administration of the immunosuppressive drugs that must be administered centrally. Measurement of the central venous pressure (CVP) has been used in the past to determine if the volume status of the recipient is adequate at the time of reperfusion of the allograft. Alternative newer technologies based on pulse pressure variation and stroke volume variation are currently being validated as tools to determine volume responsiveness. Rarely is transesophageal echocardiography or pulmonary artery catheterization necessary except in those patients with severe cardiac disease (cardiomyopathy) or pulmonary hypertension. Direct arterial catheters are also used infrequently except in compromised patients where frequent blood gases must be determined25 or there is a need to monitor blood pressure more closely, as in those with cardiac disease or cardiomyopathy.
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Immunosuppression has been the key to success of organ transplantation. The major thrust has been to improve long-term allograft survival. There is considerable variation of immunosuppressant protocols among institutions. To improve long-term allograft survival, researchers are trying to minimize exposure to drugs that are used to prevent acute cellular rejection.41 Commonly used agents for immunosuppression are calcineurin inhibitors (cyclosporine, tacrolimus), antiproliferative agents (mycophenolate mofetil), rapamycin (mTOR) inhibitors (sirolimus, everolimus), corticosteroids, and monoclonal and polyclonal antibodies. Occasionally, reactions to immunosuppressive drugs occur.42 For example, cyclosporine administration can result in hypomagnesemia, rhabdomyolysis, and other electrolyte disorders.43 Reactions to antibody OKT3 can be severe and result in hypotension and pulmonary edema. Treatment with diphenhydramine, vasopressors, steroids, diuresis, and postoperative ventilation may be required.25
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Intraoperative volume expansion is widely used and is supported by studies that have shown increased renal blood flow and better immediate graft function with generous volume administration.44 Immediate graft function is associated with increased allograft and patient survival.5 One method to ensure adequate volume expansion in patients with good cardiac function is to raise the central venous pressure to 14 or 15 mm Hg with intravenous normal saline or 5% albumin prior to perfusion of the allograft. If the patient is relatively anemic (Hgb <10 g/dL), packed red blood cells may be used for this purpose as well. One needs to be aware that static measures of volume, such as CVP or pulmonary capillary wedge pressure, may not be reliable measures of volume responsiveness, especially in patients with decreased cardiac function. Dynamic measures such as pulse pressure variation, stroke volume variation, and changes in aortic flow velocity may be better but have not been extensively studied in this population.45 Furthermore, new studies suggest that overly aggressive fluid administration may not be necessary.46
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In spite of adequate volume expansion, hypotension can still result from products of ischemia from the graft or lower extremity when the vascular clamps are released. The microvasculature of the graft and lower extremity are maximally vasodilated with reperfusion after a period of ischemia and can result in a low peripheral resistance. Therefore, it is helpful to intentionally raise the systolic blood pressure to 130 or 140 mm Hg by reducing the concentration of inhaled anesthetic agents administered prior to reperfusing the allograft. A vasopressor such as ephedrine (5-10 mg), phenylephrine (100-200 mcg), or an infusion of dopamine (3-5 mcg/kg/min) is occasionally required to treat hypotension during and after reperfusion. One advantage dopamine has over the other vasopressors is that it can increase diuresis in the allograft. However, graft survival has not been shown to increase despite this increased diuresis.5
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Mannitol administration (0.25-1 g/kg) prior to perfusion of the allograft, when combined with volume expansion, has been shown to decrease the incidence of acute tubular necrosis in the transplanted kidney. The mechanism by which it does this may be related to decreasing tubular swelling by its osmotic effect, its action as a free-radical scavenger, or by flushing away sloughed renal tubule cells before they can cause injury by secondary obstruction.47 Other diuretics such as furosemide can be administered to enhance diuresis, but have not been shown to reduce the incidence of acute tubular necrosis or delayed graft function in the transplanted kidney.5
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Monitoring Urine Output
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After reperfusion of the allograft, the urine output, intravascular volume, and overall circulatory status should be followed carefully. Hypovolemia, hypotension, acute tubular necrosis, or acute rejection can result in diminished urine output. Evaluation of decreased urine output posttransplant usually begins with an assessment of the patient's volume status. A biopsy of the transplanted kidney may also be necessary to determine if the patient is suffering from acute tubular necrosis or graft rejection.25
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Decreasing urine output may indicate a reversible surgical problem. Anuria may also be due to a mechanical factor. Vascular complications such as arterial thrombosis, arterial stenosis, or venous occlusion may result in oliguria. Distal obstruction of the ureter by a clot or kinking, or pressure on the kidney by a lymphocele or hematoma may compromise function of the new kidney as well. Fortunately, many of the mechanical causes of oliguria are correctible, if the diagnosis can be made in a timely fashion.25
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Postoperative Considerations and Complications
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Most patients do not require admission to the intensive care unit in the postoperative period provided the nursing unit is experienced in the care of transplant recipients. In addition to providing the standard postoperative care for a patient who has undergone major abdominal surgery, the function of the new kidney must be followed carefully in the transplant recipient. Rejection, viral infection, vascular thrombosis, and urinary obstruction are all complications that may occur in the perioperative period.25
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However, the most common causes of death after transplantation are cardiovascular-related events, and studies estimate a 3-year cumulative incidence of myocardial infarction of 4.7% to 11%.48 Up to 6% of patients with coronary artery disease experience a cardiac complication within 30 days of transplantation.49 Providing perioperative β-blockade, normothermia, maintaining a hematocrit of greater than 30%, and ensuring that patients have optimum analgesia in the perioperative period are all measures that may help reduce the risk for patients with cardiac disease undergoing renal transplantation.5
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Anesthetic Considerations for Patients with Prior Renal Transplantation
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Even with a functioning graft, the renal excretion of drugs in transplant recipients is usually decreased when compared to those with normal functioning native kidneys. Further, recipients may still suffer from their other systemic disease, such as diabetes or hypertension that resulted in their renal insufficiency initially. Therefore, the anesthetic care of patients with a prior renal transplant is similar to the transplant itself. Muscle relaxants that depend on renal excretion for their elimination, such as pancuronium, should be used only with the recognition that there may be delayed excretion. Adequate hydration should be ensured in the perioperative period and hypotension avoided to ensure adequate perfusion to the allograft.50
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Long-term immunosuppression can result in significant morbidity in kidney transplant recipients.51 The effect of immunosuppressive drugs should be considered when evaluating a kidney transplant recipient for nontransplant surgery. For example, cyclosporine use may cause hypertension and hyperlipidemia, and worsen atherosclerosis in kidney transplant recipients. Tacrolimus is associated with new-onset diabetes after transplant. Most patients have adrenal suppression to some degree because of long-term steroid use. Therefore, a stress dose of steroids may be necessary in renal transplant recipients who have received steroids for immunosuppression.50
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Special Considerations in Pediatric Patients
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The anesthetic care of older children and adolescents is similar to adults. Infants and small children less than 2 years of age are more challenging. Infants and small children usually receive an adult kidney rather than one from a donor similar in age because there is a high incidence of vascular thrombosis with allografts from infants and small children. However, an adult kidney is so large compared to an infant that it must be anastomosed to the infant's aorta and vena cava rather than the iliac vessels (see Fig. 59-2) as in older children or adults.52 Therefore, the aorta and vena cava both must be cross-clamped during performance of the vascular anastomoses. The adult kidney can sequester up to 300 mL of blood upon reperfusion. Reperfusion can also result in acidosis from the ischemic organ and lower extremities. Hyperkalemia may result from absorption of the standard hyperkalemic (University of Wisconsin) preservative solution. Hypothermia may result with reperfusion of the allograft. Ischemic vasodilatation upon reperfusion of the allograft can also result in a low peripheral vascular resistance and hypotension. In addition, the adult kidney can initially produce urine at a rate equal to the patient's blood volume every hour.53 All this dictates that caregivers pay close attention to circulatory hemodynamics in young infants receiving an adult kidney allograft.
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The goals of the anesthetic management of kidney transplantation in infants and small children are the same as those for older children and adults. Adequate volume expansion must occur to prevent severe hypotension upon perfusion of the allograft. Often a permanent, large-bore (2-mm internal diameter) dialysis catheter is valuable for central vascular access and also provides a means for hemodialysis if the kidney does not function immediately. Direct arterial pressure monitoring is useful in infants and very small children because blood pressure changes can be rapid and profound. In contrast to older children and adults, in infants the central venous pressure must be increased to 16 to 20 mm Hg before reperfusion of the allograft. Colloids such as 5% albumin as well as blood products are generally used for this purpose. The amount of colloids and/or blood products administered can be profound. In 1 review of infants and small children receiving an adult kidney transplant, the amount of colloids and/or blood products administered averaged 90 ±41 mL/kg.53
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Postoperative Admission to Intensive Care Unit
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Postoperatively, pediatric patients are at an increased risk for pulmonary edema. Most pediatric patients tolerate the volume administration without morbidity. In 1 review of 24 infants receiving an adult kidney transplant, 17 (71%) were extubated in the recovery room, and most of the others in the intensive care unit the following day. Only 2 patients (8.3%) required mechanical ventilation beyond 24 hours to aid in fluid management. However, 7 of the 24 patients (29%) had radiographic evidence of pulmonary edema on the postoperative chest x-ray. Therefore, the pulmonary status of pediatric patients should be monitored in an intensive care unit setting following surgery, and some may require postoperative ventilatory support.53
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Approximately 25000 patients per year now receive a kidney transplant, either from a living or cadaver donor. The most recent 1-year graft survival is 92% from cadaveric nonextended criteria donors, 85% from extended criteria donors, and 96% from living related donors. At 5 years, the graft survival is 81% from living related donors, 72% from cadaveric nonextended criteria, and 57% from cadaveric extended criteria donors. The 5-year patient survival is 84% to 72% for recipients of cadaveric organs and 91% for recipients of living donors. In addition, comparison with earlier data shows improved survival of both patients and the allografts over time.54 Renal transplantation has become one of the great success stories in medicine.
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The future may give us a new understanding of transplant failure. Recent genetic research has identified a gene variant in the CAV1 gene of kidney donors that carries a higher risk of graft failure following transplantation. This finding may allow us to identify biomarkers that predict graft survival ahead of time.55
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Kidney transplantation offers both better survival and a better lifestyle to patients in renal failure. Patients with renal failure are a challenging group for the reasons discussed above. With careful anesthetic care, knowledge of the pathophysiology of renal failure and associated disease, and understanding of the physiology of perfusion of the renal allograft, satisfying outcomes can be obtained.