Renal transplant




I Renal transplant




1. Introduction

Renal transplantation has been performed for nearly a century and is an accepted means of replacing kidney function in patients with end-stage renal disease who are on maintenance dialysis. In this procedure, the donor kidney is placed extraperitoneally in the recipient’s iliac fossa. The renal artery is anastomosed to the internal iliac artery, the renal vein to either the external or the common iliac vein and the ureter to the bladder. The anesthesia provider plays a vital role in management of the viability of the transplanted kidney. Three interrelated variables affect surgical outcomes: management of the donor, preservation of the harvested organ, and perioperative care of the transplant recipient. Additionally, improved surgical and immunosuppressive techniques have contributed to better outcomes in terms of graft survival.



2. Preoperative assessment and patient preparation
a) Harvested organ preservation
(1) Ischemic time, beginning with the clamping of the donor’s renal vessels and ending with the vascular anastomosis in the recipient, is a crucial factor in graft preservation. When renal ischemic time is less than 30 minutes, diuresis begins quickly, but if it is 2 hours or longer, a variable period of oliguria or anuria may occur. The definition of renal ischemic times for warm and cold preservation techniques is noted in the following table.


Definition of Ischemic Time















  Warm Cold
Begins Clamping of donor vessels; initial placement in recipient Perfusion of harvested organ with cold preservation solution; storage at 4° C
Ends Vascular anastomosis in recipient; interrupted with perfusion of cold preservation solution Perfusion by recipient



b) Donor preparation
(1) Choice of anesthesia for the living, related donor is not critical.

(2) Adequate amounts of balanced salt solution should be administered to ensure a brisk diuresis from the donor kidney and to offset reduced venous return resulting from use of the flank position.

(3) The greatest risk to the donor is hemorrhage.

(4) Adequate IV access and blood must be available in the event that transfusion becomes necessary.

(5) If the donor kidney is obtained from a brain-dead patient, preservation of graft function is the highest priority. The loss of sympathetic tone after brain death may produce mild hypotension despite adequate volume replacement. Many patients with irreversible cerebral dysfunction are hypovolemic and require vigorous fluid resuscitation.

(6) If pharmacologic support of the cardiovascular system is necessary, a dopamine infusion at a rate of 1 to 3 mcg/kg/min is recommended. Renal vasoconstrictive properties of high-dose vasopressors reduce immediate allograft function and increase the risk of kidney damage. Maintenance of urinary output is paramount and may warrant the use of diuretics and a low-dose dopamine infusion.

c) Recipient preparation
(1) Because cadaveric kidneys can be preserved for 36 to 48 hours with cold perfusion, time is sufficient for optimal preparation of the transplant recipient.

(2) The recipient should be free of acute illness and infections because of the likelihood of their spread during immunosuppressive therapy.

(3) Acute alterations in fluid and electrolyte balance should be corrected with dialysis carried out 24 hours before transplantation. Postdialysis laboratory values should be checked, and the serum potassium (K+) level should be below 5.5 mEq/L. Coagulation studies and acid–base status should be normal. Serum creatinine concentration should be below 10 mg/dL and blood urea nitrogen level below 60 mg/dL after dialysis.

(4) Anesthetic considerations are summarized in the following box.

 



Anesthesia for Renal Transplant




I Preoperative assessment and preparation
A Clinical evaluation
1. Evaluate status of coexisting diseases

a. Diabetes mellitus

b. Hypertension

c. Cardiac disease

d. Hyperparathyroidism

e. Pericardial tamponade

2. Perform dialysis within 24 hours of transplantation; check weight

3. Evaluate tolerance to chronic anemia

B Laboratory evaluation
1. Complete blood count with platelet count

2. Prothrombin time, partial thromboplastin time, bleeding time

3. Blood urea nitrogen, creatinine, calcium, fluid balance

4. Electrocardiography; chest radiography

C Type and cross-match 2 units of washed packed red blood cells

D Determine current drug regimen

E Premedication
1. Benzodiazepines, narcotics

2. Antacids, histamine-2 antagonists, metoclopramide

II Monitors
A Electrocardiography

B Indirect or direct blood pressure measurement

C Precordial, esophageal stethoscopy

D Neuromuscular blockade evaluation

E Foley catheter

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Dec 2, 2016 | Posted by in ANESTHESIA | Comments Off on Renal transplant

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