Questions
- 1.
What are the classifications of chronic kidney disease?
- 2.
How are patients selected for combined kidney-pancreas transplantation?
- 3.
What are the major anesthetic concerns for kidney-pancreas transplantation?
- 4.
- 5.
Explain the relationship between acidemia and hyperkalemia.
- 6.
Discuss the implications of fluid management in kidney-pancreas transplantation.
- 7.
What is the role of transversus abdominis plane block for abdominal surgery?
A 44-year-old woman with type 1 diabetes mellitus (DM), hypertension, hypothyroidism, and stage 5 chronic kidney disease (CKD) presented for cadaveric kidney-pancreas transplantation.
1
What are the classifications of chronic kidney disease?
CKD is classified based on the presence of kidney damage and glomerular filtration rate ( Table 39-1 ). Kidney damage is determined by either pathologic findings or abnormal markers found in blood, urine, or imaging. End-stage renal disease is termed stage 5 CKD.
| Stage | Glomerular Filtration Rate (mL/minute/1.73 m 2 ) |
|---|---|
| 1 | >90 |
| 2 | 60–89 |
| 3 | 30–59 |
| 4 | 15–29 |
| 5 | <15 or dialysis |
2
How are patients selected for combined kidney-pancreas transplantation?
Pancreas transplantation alone is indicated for patients with severe and difficult-to-control type 1 DM without evidence of renal dysfunction. In rare circumstances, it may be indicated in patients with DM secondary to chronic pancreatitis or cystic fibrosis. Eligibility criteria, which can differ from institution to institution, include age, human immunodeficiency virus (HIV) status, and body mass index.
C peptide is generated during insulin biosynthesis and is released into the portal circulation along with insulin. Measurement of C peptide levels can confirm the absence or decreased production of insulin by the pancreas. C peptide levels <0.3–2 ng/mL are confirmatory evidence of the need for pancreatic transplantation. Additionally, a history of intolerance to insulin therapy and a history of recorded low glucose levels without the expected symptoms of hypoglycemia, such as diaphoresis, headache, and abnormal mentation or confusion, are indications for pancreas transplantation.
Kidney transplantation is indicated in patients with stages 4 and 5 CKD. In the United States at the present time, the most common etiology for CKD and subsequent need for kidney transplantation is diabetic nephropathy. When type 1 DM and CKD are present, as is the case in 50%–60% of patients, simultaneous pancreas-kidney (SPK) transplantation or pancreas transplantation after kidney transplantation may be performed. The best results with respect to graft survival appear to occur with SPK transplantation.
In 2010, >828 SPK transplantations were performed in the United States. Although there have been >40 cases of living related pancreas-kidney transplantations performed, most transplants are obtained from deceased donors. The United Network of Organ Sharing is responsible for cadaveric organ allocation. Organ matching is done based on major blood group (ABO) compatibility followed by human leukocyte antigen (HLA) profiling of the recipient. A crossmatch is performed between the recipient and the donor blood cells to determine if the recipient has antibodies against donor antigens. HLA matching previously was a high priority for organ matching; however, improved outcomes with newer immunosuppressant medications have diminished the importance of tissue typing.
3
What are the major anesthetic concerns for kidney-pancreas transplantation?
The anesthetic evaluation and management of patients undergoing SPK transplantation is directed at identifying and optimizing organ dysfunction or metabolic abnormalities that are associated with advanced DM and CKD. For a full discussion of the preoperative evaluation and anesthetic management of patients with DM, see Chapter 26 .
Preoperative evaluation generally includes history, physical examination, electrocardiogram (ECG), and laboratory studies. These assessments are sufficient to evaluate most patients undergoing surgery, but a more extensive cardiac evaluation is indicated for patients with type 1 DM and coexistent renal dysfunction because of accelerated plaque formation. In patients with coexistent type 1 DM and CKD stage 5, significant coronary artery stenosis was found in at least one coronary artery in 87% of patients. Dobutamine stress echocardiography may be particularly helpful in screening patients before SPK transplantation because many of these patients are unable to achieve the desired heart rate with treadmill stress testing. Coronary angiography is indicated in patients with positive results. At some centers, coronary angiography is routinely performed in all patients undergoing SPK transplantation who are >45 years old or who have had type 1 DM >25 years. This practice may detect patients with significant stenosis that may or may not be amenable to coronary intervention.
Laboratory studies that may be altered include serum sodium, potassium, and glucose levels, hematocrit, and pH. Timing of last hemodialysis, in addition to vital signs, is important preoperative information that can help determine the patient’s volume status, degree of uremia, and platelet dysfunction.
Patients with type 1 DM, characterized by insulin deficiency, are at risk for hyperglycemia and ketosis without adequate insulin treatment. Poorly controlled DM can affect multiple organ systems and result in peripheral and autonomic neuropathy. Autonomic neuropathy may cause impaired gastric emptying, increasing the risk of aspiration during induction of anesthesia. Sodium citrate/citric acid, H 2 blockers, and metoclopramide before rapid-sequence induction and intubation may be indicated to reduce the risk of pulmonary aspiration. Neuropathy could render these patients unable to sense angina during periods of myocardial ischemia. Neuropathy can also result in either an extreme lability in heart rate and blood pressure or in a fixed bradycardia that does not change in the face of increased demand. These alterations can increase the risk of perioperative dysrhythmias and cardiovascular events.
Many patients have hypertension and may be taking different classes of antihypertensive medications to lower their blood pressure. Additionally, they may have anemia owing to decreased erythropoietin production and impaired platelet function from uremia. Figure 39-1 shows the multisystemic effects of diabetes and uremia and their relationship with each other.
SPK transplantation takes several hours to perform and requires profound muscle relaxation to allow for adequate exposure through a large midline incision. As a result, general anesthesia is nearly always employed. No one technique is superior to others. However, it is important to understand the implications of coexisting diseases, particularly renal failure, on the pharmacology and effects of various medications and adjuvants ( Box 39-1 ). Intrathecal morphine, epidural catheter placement, or transversus abdominis plane (TAP) blocks may be performed to decrease postoperative pain but are unacceptable as primary anesthetic plans. Epidural anesthesia could result in splanchnic hypoperfusion and excessive crystalloid administration leading to swelling of the donor pancreas. Colloid solutions may offer an advantage over crystalloid solutions by reducing pancreatic swelling and may reduce graft function complications.
Preoperative concerns
- •
Electrolyte abnormalities
- •
Hyponatremia <131 mEq/L or hypernatremia >150 mEq/L
- •
Hypokalemia <2.5 mEq/L or hyperkalemia >5.9 mEq/L
- •
Hyperphosphatemia, hypermagnesemia, hypocalcemia
- •
- •
Glucose
- •
Medication history—insulin and oral hypoglycemic agents
- •
Presence of pump, basal rate, 24-hour basal insulin requirement
- •
Endocrinology consultation
- •
- •
Anemia
- •
Anemia is often chronic secondary to decreased erythropoietin
- •
- •
Coagulopathy
- •
Platelet dysfunction secondary to uremia; corrected with dialysis
- •
- •
Dialysis
- •
Knowledge of dry weight, recent dialysis can indicate relative hypovolemia
- •
Potential hypotension on induction of anesthesia
- •
- •
Conversely, several days without dialysis may indicate hypervolemia
- •
Potentially associated with cardiovascular overload, pulmonary edema
- •
- •
- •
Cardiovascular risk
- •
Determine presence and degree of coronary artery disease
- •
Intraoperative considerations
- •
Benzodiazepines
- •
Effect potentiated by hypoalbuminemia
- •
- •
Gastroparesis
- •
Aspiration precautions and rapid-sequence induction
- •
- •
Hyperkalemia
- •
Levels >5.5 mEq/L may contraindicate use of succinylcholine
- •
Prepare for treatment of hyperkalemic arrest
- •
- •
Coagulopathy
- •
May contraindicate neuraxial anesthetic
- •
TAP block may be helpful to reduce postoperative pain
- •
- •
Arterial catheter placement to guide fluid, insulin, and ventilatory settings
- •
Allows for continuous blood pressure monitoring
- •
- •
Intravenous access
- •
Avoid sites of arteriovenous fistulas and shunts
- •
Central access may be required in certain circumstances
- •
- •
Intravenous fluids
- •
Normal saline solutions may predispose to hyperchloremic acidosis
- •
PlasmaLyte and lactated Ringer’s solution as long as patient is not hyperkalemic
- •
½ NS with 75 mEq/L sodium bicarbonate
- •
May improve pH and reduce base deficit
- •
- •
Benefits of colloid solutions are unknown but may include
- •
Decreased total crystalloid administration
- •
Decreased edema in the donor pancreas and improved microcirculation
- •
- •
- •
Induction agents
- •
Propofol, etomidate, and barbiturates are protein bound
- •
Dose may need to be reduced in patients with renal failure and hypoalbuminemia
- •
- •
- •
Volatile agents
- •
Recommend isoflurane and desflurane
- •
Desflurane may result in less residual anesthetic postextubation
- •
- •
Sevoflurane
- •
Release of free fluoride ions does not result in clinical differences in renal transplant function
- •
- •
- •
Opioids
- •
Meperidine
- •
Accumulation of normeperidine, active metabolite; lower seizure threshold
- •
- •
Morphine
- •
Accumulation of morphine-6-glucuronide, active metabolite
- •
- •
Fentanyl and remifentanil
- •
Relatively unchanged pharmacokinetics
- •
- •
- •
Muscle relaxants
- •
Succinylcholine
- •
May increase potassium by 0.5–1.0 mEq/L
- •
- •
Cisatracurium
- •
Hoffman elimination (does not accumulate in renal failure)
- •
- •
Rocuronium
- •
Slightly prolonged duration; primarily hepatic excretion
- •
- •
Vecuronium
- •
Slightly prolonged duration; primarily biliary and hepatic excretion
- •
- •
- •
Steroid
- •
Methylprednisolone
- •
Given before surgical incision, may result in hyperglycemia
- •
- •
- •
Immunosuppressant
- •
Antithymoglobulin
- •
Infused 1 hour after methylprednisolone is administered; anaphylaxis
- •
- •
Other immunosuppressant drugs administered after surgery include mycophenolate, sirolimus, cyclosporine, and tacrolimus
- •
- •
Vasoactive agents
- •
Norepinephrine, epinephrine, phenylephrine, ephedrine, vasopressin
- •
Constrict blood vessels, may impair organ microcirculation, contribute to third spacing
- •
Large studies do not support the use of a particular pressor over the other
- •
- •
Dopamine
- •
Dilates renal arterioles, decreases renal vascular resistance, improves renal blood flow
- •
No evidence demonstrating renal protection
- •
- •
Fenoldopam
- •
Direct dopamine agonist, improves renal blood flow without β-adrenergic activity
- •
- •
Sodium nitroprusside
- •
Contains cyanide, which is metabolized to thyocyanate; thyocyanate is excreted by the kidneys and is neurotoxic
- •
- •
- •
Fluid loading before vascular anastomosis
- •
Diuretics
- •
Mannitol and furosemide
- •
Use varies by surgeon and institution
- •
- •
NS, Normal saline; TAP, transversus abdominis plane.
Related posts:
Full access? Get Clinical Tree
