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SR Gupte*, Smita Sharma**
Introduction
The first successful transplant was done
in Boston in December 1954. This was done from one identical twin to another. From the beginning of the sixth decade active work had started in Boston, London and Paris, and this was followed by rest of the world and some places in India also.
At the Bombay Hospital Institute of Medical Sciences, Kidney transplant began in 1983 and to date we have done about 1000 successful kidney transplants.
We were relatively inexperienced in the field when we started. After going through the literature available on the subject, we realized that most of the drugs recommended for anaesthesia in these patients were not available in India at that time. We took a stock of the situation and managed with what was available, taking some extra care. The first 250 transplants were managed with the drugs available at that time and then we gradually shifted to the newer drugs as they became available, which were supposed to be ideal.
In these initial cases though we did not have the ideal drugs we managed them without any major complications or handicap to the patient.
Way back in 1966, Strunin had reported a perioperative mortality of 16%. In recent series Marshland and Bradley (1983) and Heino et al (1986) have reported perioperative mortality of 0.03% and 0.06% respectively. Common complications were dysarrhythmias, hypotension and hypertension.
In our own thousand cases immediate post operative mortality was 0%. The purpose of this mention is more to emphasize the fact that with due care and caution and good nephrological preparation of the patient, one can achieve good results.
The 5 year survival rate for kidney transplant today is about 80% internationally.
Five year survival rate with dialysis is about 30%. Clearly kidney transplant provides better quality of life and is preferable to a life dependent on dialysis.
As Sear has stated there is no ideal technique of anaesthesia for kidney transplant. Safe and effective anaesthesia depends on the understanding of the pathophysiology and biochemistry of the uraemic patient and its effects on the pharmacokinetics and metabolism of drugs used. As the criteria for accepting patients for renal transplantation broaden, the anaesthesiologist will be faced with additional problems of intercurrent diseases, drug therapies and old age problems.
In brief we will try and enumerate the different problems posed by these cases for the anaesthesiologists, how we manage them, and our own general impressions which might be useful to new entrants in the field.
A patient in chronic renal failure is a suffering person. He has multiple metabolic and other associated problems, mainly due to uraemia and others due to nonfunctioning of the kidneys.
High S Creatinine and Blood Urea
All patients coming to us for transplant are expected to have high creatinine and urea. We usually see S Creatinine in the range of 5-6 mg% after dialysis, and urea in the range of 70-80 mg%.
Acid Base and Electrolyte Status
Patients with renal failure have an inability to excrete water, electrolytes and free acids. The expected and usual picture is hyponatraemia, hyperchloraemia, hyperkalaemia and metabolic acidosis.
The severity of these problems is related to the duration of disease (CRF). In our routine practice these patients come to the operation theatre with 2 consecutive dialysis, on previous days, so these problems are minimized. Acceptable values of S Electrolytes to perform this elective operation are
S Na not less than 125 Meq/L
S K not more than 5 Meq/L
Anaemia
Patients of CRF are usually anaemic due to reduced erythropoietin synthesis and release, decreased RBC life span, increased haemolysis and bleeding and, repeated blood loss during haemodialysis and aluminium toxicity.
Hb is usually in the range of 5 to 8 gm/dl. It is a normocytic normochromic anaemia. Low Hb reduces the O2 carrying capacity significantly and compensatory actions come into play. To maintain adequate tissue oxygenation it is important to avoid fall in cardiac output during induction and maintenance of anaesthesia. If Hb is below 6 gms/dl transfusion is indicated. Today due to the routine administration of erythropoietin the patients have improved Hb in the range of 9 to 10 gm/dl, and the patients rarely need transfusions.
Chronic Hypertension and Heart Disease
Incidence of hypertension in CRF is in the range of 68-94% in patients undergoing renal transplant.
Ischaemic heart disease is far less common in those who come forward for transplant.
All patients with abnormal stress tests or those with symptomatic ischaemic heart disease should preoperatively undergo coronary angiography followed by indicated treatment.
It is very important to continue antihypertensive drugs perioperatively. Due to anxiety there will be a small rise in blood pressure when the patient is brought to the operation theatre. A smooth induction is important at this stage.
Coagulopathies
Uraemic coagulopathy is due to abnormal platelet function and ineffective production of both factor VIII and platelet von Willebrand factor.
Venous Access
Due to repeated procedures, fistulas, shunts and blood investigations, veins are difficult to find. We canulate 1 peripheral vein with a no 16 canula on the hand which does not have the fistula, and insert the central line (IJV) after induction of anaesthesia. These 2 portals take adequate care of the infusions and transfusions during the surgery.
Problems Related To Haemodialysis
- Excessive heparinisation
- Abnormal fluid shifts
- Transmission of viral infections (Hepatitis A, B, HIV and cytomegalovirus).
General Ill Health
The patients are generally ill and most of their vital functions do not work 100%.
The various multisystemic problems are General malaise, Low proteins, Peripheral neuropathy, Uraemic lung, Greater susceptibility to infections, Secondary hyperparathyroidism, Gastric acidity and delayed gastric emptying, Hiccups.
They should be given all drugs carefully treating them as patients 10 to 12 years of age.
Anaesthesia for Kidney Transplant – A Recommended Practice
A) Management of Donor
Donor nephrectomy can be done as an open procedure or laparoscopically. The donor is a fit and healthy person, ASA Grade 1 or 2 and comes forward for a noble cause. Even a minor morbidity is not acceptable and mortality is unforgivable. He is expected to have an uneventful anaesthesia course.
Salient Features of Donor Management
1. There should be no fall in blood pressure
2. IV fluid administration is on the higher side, keep a good watch on the urine output.
These measures aim at maintaining a good perfusion of the kidney that is going to work in the recipient’s body.
B) Management of The Recipient
Anaesthesia for the kidney recipient can be conducted under
1. General Anaesthesia
2. Epidural Anaesthesia
3. Combination of General and Epidural Anaesthesia
4. Combination of Spinal and Epidural Anaesthesia.
The authors recommend General Anaesthesia for the following reasons:
1. It is safest and there is complete control over the blood pressure.
2. SA/EA are not comfortable for the patient, for the long time the surgery takes and excessive sedation defeats the purpose.
3. Impaired coagulation can lead to epidural bleeding and haematoma formation.
Induction and Maintenance of Anaesthesia
Poor renal function for the anaesthesiologist translates as delay in excretion of most of our anaesthetic drugs, particularly the non depolarizing muscle relaxants. There are changes in the pharmacokinetics of many drugs in the CRF patients and some of the active metabolites of drugs used can accumulate in the body and prolong their actions.
It is important to know the dry weight of the patient when he comes for surgery, it helps the drug dosage calculation.
Premedication
It was tried but we discontinued administering it as patients became excessively drowsy.
Sodium Thiopentone (Pentothal): Study of sodium thiopentone in CRF has proved that there is unaltered total drug elimination half life, but increased free drug fraction. Because of this increased free drug fraction available, it is important to note that it is not the dose of thiopentone that needs to be reduced for induction but the speed of administration.
Succinycholine: It deserves a special mention. In our experience we always use succinycholine as the drug of choice for intubation. While it is true that succinycholine raises the S K value by about 0.5 to 1 MEq/L, it does not cause a massive efflux of potassium (very different from burns and denervating disorders). Hence it is safe for S K levels upto 5.5 MEq/L. It has the obvious advantage of reducing the overall requirement of maintenance muscle relaxants, and helps to achieve smooth induction.
Sevofluorane is the latest inhalatonal agent and considered safest and most popular. However it produces inorganic fluorides which are nephrotoxic, hence it is best avoided. Isofluorane is an equally good option.
Our standard practice is as follows
Induction of Anaesthesia - Sodium thiopentone + Succinylcholine
Maintenance N20 +O2 + Isofluorane or Halothane
Atracurium
Fentanyl or pentazocine
Today propofol is an alternative but it causes fall in blood pressure at the time of induction of anaesthesia, hence utmost caution is needed; we avoid it.
Elimination of muscle relaxants
Pancuronium 40 to 50 % by kidney
Vecuronium 25% by kidney
Atracurium Hydrolysis in the body, hence ideal for use in these cases.
We used pancuronium successfully for years. The caution we exercised was to use very low doses. Augmented biliary excretion in the absence of kidney function may also have contributed to its excretion along with the immediate functioning of the transplanted kidney.
Intubation and Ventilation
Intubation has to be smooth with minimum haemodynamic disturbance.
Ventilation should be normocapnia or mild hypocapnia.
Even short periods of hypoventilation can lead to Hb desaturation whereas hyperventilation will cause a shift of oxy Hb dissociation curve to the left.
IV Fluid Management
Fluids are infused depending on the CVP measurement. With 2 preoperative dialysis the patient comes to us with a CVP of 5-7 cms of H2O i.e. they are in negative balance.
Before vascular anastomosis
1500 to 2000 ml saline and ringer lactate should be transfused to bring the CVP upto 15-20 cms of water.
After vascular anastomosis
CVP is maintained between 20-23 cms of H2O. Ringer lactate + 0.45% Normal saline with 40 mmols of sodum bicarbonate in four units. This maintains the buffer balance in the body and prevents saline acidosis.
We now strongly believe that a good CVP contributes in a big way to a good urine output in the transplanted kidney. With this fluid management 90% of the kidneys start throwing urine while the patient is on the table. If the urine output is slow, furesamide is found to be beneficial, starting with a small dose of 20 mg and increasing depending upon the response of the kidney.
After established urine output
Urine output + 500 ml/hr
Drugs
Important drugs at the time of vascular anastomosis
1) Methylprednisolone
2) Mannitol
Blood Pressure Management
Intraoperative swings of blood pressure are common more so in patients requiring multi drugs for control of blood pressure The patient of CRF is used to a slightly higher blood pressure and that is maintained intraoperatively. We use nitroglycerine for control of BP when depth of anaesthesia alone is not sufficient
Monitoring
We routinely monitor, ECG, Non invasive BP, Pulse oxymetry, ETCO2, CVP, Urine output, body temperature and ventilatory parameters.
Care of AV Fistula
1. Proper positioning of arm to avoid mechanical injury.
2. Cover and wrap the arm in guaze padding
3. Blood pressure measurements should not be taken on the arm.
4. Avoid hypotension
5. Avoid dehydration
6. Avoid injections both IV and IM on that hand.
Reversal of Anaesthesia and Extubation
Patients are reversed and extubated on the table. For a successful reversal drug dosages should be just adequate for the procedure, in our entire series, we had to give ventilatory support to only two patients, that too for a short time.
-Throughout the operation it is important to keep in mind that the patient may not pass urine after the kidney is transplanted, fluids should be restricted at this stage.
Post Operative Pain Relief
1. Avoid NSAID completely
2. Tramazac
3. Proxyvon
4. Buteronorphine
Cadaver Transplant
Being done since 2001 at our hospital.
Brain death is:
Fundamentally irreversible loss of both cortical and brain stem function.
The criterias and guidelines of brain death and organ transplantation have to be strictly met.
The challenges for the anaesthesiologist are
1. Harvesting the donor kidney
2. Longer periods of cold ischaemia to the kidney ( not more than 24 hours)
3. A semi emergency situation so apart from the usual problems the recipient may not be fully prepared patient.
Conclusion
Carefully used drugs considering the general ill health of the patient, fluid shifts due to previous dialysis should be given importance while anaesthetizing a recipient of kidney transplant. Avoidance of drugs excreted by the kidney, proper maintainence of CVP at the time of renovascular anastomosis contributes to a successful outcome.
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