Anaesthesia for living donor renal transplant nephrectomy

Transcription

1 Anaesthesia for living donor renal transplant nephrectomy Benjamin O Brien MD FRCA FFICM Marta Koertzen FRCA 2A07 2C06 Key points Living donor nephrectomy involves unique ethical considerations. Fit and healthy patients are exposed to risks inherent to major surgery with no benefit to the patients themselves. The number of living donor renal transplants are increasing. Benefits over deceased donor transplants include documented improved patient and graft survival, lower incidence of delayed graft function and shorter time waiting for an organ. Regional techniques complement general anaesthesia for open and laparoscopic techniques. Perioperative complications in the donor are rare, but consultant led care, careful thromboembolism prophylaxis, and follow-up are mandatory. Benjamin O Brien MD FRCA FFICM Consultant in Intensive Care Medicine and Cardiothoracic Anaesthesia St Bartholomew s Hospital Barts Health NHS Trust Intensive Care Unit 2nd Floor QE II Wing St Bartholomew s Hospital London EC1A 7BE UK Tel: þ ben.obrien@bartshealth.nhs.uk (for correspondence) Marta Koertzen FRCA Consultant Anaesthetist Hammersmith Hospital Imperial College Healthcare NHS Trust London W12 0HS UK 317 Living donor nephrectomy (LDN) carries unique ethical considerations. The patient is exposed to risks inherent to major surgery with no benefit to themselves. Living donors demonstrate an extreme level of altruism and motivation. The prevalence of patients in end-stage renal failure (ESRF) is increasing. 1 After advances in perioperative care and postoperative immunosupression, renal transplant is considered to be the best therapeutic option for ESRF. The procedure is commonly classified according to the source of the donor organ (Fig. 1). 1 Epidemiology The percentage of transplants from living donors is increasing. The latest available UK figures reveal that in March 2009, 7190 patients were registered on the active transplant list, awaiting renal transplants. This represents an increase of 3% compared with the previous year. In total, 2532 patients received a renal transplant last year, of which 37% (927) received a kidney from a living donor. This amounts to a 12% increase in living donor transplant procedures year-on-year. 1 Advantages of live donation Living donation by increasing the donor pool increases the organs available for transplantation, easing the lack of organ availability. Living donor renal transplant is an elective procedure and the timing of an operation is flexible. Recently, the indication for transplantation has been brought forward in the disease progression (Fig. 2). Completely pre-emptive renal transplants are however still the exception and recipients have usually been started on some form of renal-replacement therapy. Kidneys transplanted from living donors show an increased graft survival (Fig. 3). Thus living donor renal transplant is now the procedure of choice and improved public awareness has increased the number of donors prepared to make this sacrifice. 2 Ethics Potential donors are carefully evaluated both psychologically and medically. The donor must be fit for surgery and have no disease state that increases the risk of a poor outcome for either the donor or the recipient. The psychological assessment is to ensure the donor can give fully informed consent and is not being coerced. In the UK, the Human Tissue Act (HTA) 2004 dictates that donors must provide evidence of a familial or long-term relationship. Purely altruistic donation to strangers has only recently become acceptable. The decision must be specifically approved by a panel, whereas the typical donation based on relationship is required only to go through an independent assessor who acts on behalf of the HTA and as a representative of the donor. 2 Extremes of age are not contraindications to donation; however, individuals aged,18 are virtually never considered as potential living kidney donors. At the other end of the spectrum, biological age is considered more important than chronological age (donors as old as yr been successfully recruited). Donor Although donor nephrectomy is a major surgical procedure and puts the patient at risk of serious (if rare) morbidity and mortality, 1 donors who have successfully completed the evaluation for living kidney donation have been found to have an above average life expectancy. 3 doi: /bjaceaccp/mks040 Advance Access publication 24 July, 2012 Continuing Education in Anaesthesia, Critical Care & Pain Volume 12 Number & The Author [2012]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please journals.permissions@oup.com

2 Fig 1 Classification of renal transplants by donor organ source. (1) Related: the donor is genetically related to the recipient ( parent, child, sibling, half-sibling, aunt, uncle, niece, nephew, first cousin). (2) Paired: when a donor agrees to give one of their healthy kidneys to a known recipient, the donor and recipient will be assessed to find out if they are suitable for an exchange. In some cases, the donor and recipients blood groups or tissue types are mismatched or incompatible. If so, as a pair, they can be put forward for paired donation, where they will be matched up with another donor and recipient in the same situation. (3) Pooled: occasionally, more than two donors and two recipients will be involved in a swap. Each recipient gains from a transplant that they would not otherwise have had. The donors might not have given their kidney to the person they know, but that person will have received a kidney from one of the other pooled donors. Fig 2 Comparison of patient survival: dialysis vs renal transplant. Data from NKUDIC. 4 Fig 3 Graft survival after living-donor vs deceased-donor renal transplant. Data from NKUDIC. 4 Preoperative assessment The majority of donors are ASA I and II; however, a full preoperative assessment including accurate measurement of renal function is mandatory. Donors are classified as complicated if they are older, with comorbidities, obese (BMI.30), they refuse blood products, have vascular abnormalities (e.g. multiple renal arteries), or are required to have a right nephrectomy (which is surgically more demanding). 5 Hypertension Hypertension is no longer a contraindication as long as kidney function and urine protein are normal. 6 Data presented by Textor 7 indicates that donors with moderate essential hypertension and normal kidney function fare no worse in terms of blood pressure, glomerular filtration rate, or urinary protein excretion, during the first year after kidney donation compared with normotensive patients. 318 Continuing Education in Anaesthesia, Critical Care & Pain j Volume 12 Number

3 Fig 4 Near full lateral position with extension break at the waist. Fig 5 Key messages: perioperative anaesthetic care. A prospective donor may be on treatment for hypertension, as long as his or her blood pressure is well controlled (diastolic,83 mm Hg). The donor should be warned of the possibility that nephrectomy may worsen hypertension. Diabetes mellitus is a contraindication to live related nephrectomy; however, patients with impaired glucose tolerance may be accepted providing their fasting venous plasma glucose is,7.0 mmol litre 21, the result of an oral glucose tolerance test is,7.8 mmol litre 21 and their BMI is,30 with no family history for diabetes. Fig 6 Donated kidney. Fig 7 Surgical techniques. Perioperative management Anaesthesia for LDN Donors are at moderate risk for the development of venous thromboembolism and should receive prophylactic low-molecular-weight heparin (starting before surgery and continuing for at least 5 days or until discharge), supplemented with graduated stockings and intermittent pneumatic compression devices. 6 This has an obvious implication for timing of perioperative regional anaesthetic techniques. Anaesthetic management includes generous venous access as blood loss may, albeit rarely, be significant. Special attention should be paid to the prevention of complications related to near full lateral position (nerve damage, airway compromise, pressure sores, venous access compromise), see Figure 4. According to UK guidelines, the presence of a consultant anaesthetist and consultant surgeon is mandatory. It is vital to maintain the perfusion pressure at or above preoperative values. This is achieved through fluid preloading and maintaining a positive fluid balance throughout the procedure. Dopamine is the most commonly used inotrope should one be necessary to support mean arterial pressure. I.V. fluids should be warmed and full measures should be taken to prevent hypothermia (compare Fig. 5). Live donor nephrectomy and transplant operations are commonly performed sequentially, in the same theatre, with minimal delay to reduce ischaemic time of the donated kidney (Fig. 6). Continuing Education in Anaesthesia, Critical Care & Pain j Volume 12 Number

4 Fig 8 Frequency of complications. Laparoscopic LDN (compare Fig. 7) Ratner et al. 8 in 1995 reported the following advantages of laparoscopic opposed to open LDN: reduced blood loss, decreased tissue trauma, lower analgesic requirements, faster resumption of food intake, shorter hospitalization, quicker return to work, and better postoperative cosmetic appearance. However, laparoscopic surgery is technically more demanding and takes approximately twice as long as an open procedure. In a review of 44 studies, the conversion rate from laparoscopic LDN to an open technique was as high as 13%. 9 General anaesthesia is the only practical option for laparoscopic LDN as it involves a pneumoperitoneum and a head-down position. Postoperative considerations Postoperative pain Postoperative pain is a common problem. Open LDN is a particularly painful procedure. The subcostal wound is often long (10 12 cm in length), making breathing and coughing extremely painful. In laparoscopic LDN, the pain is due a combination of port pain, the abdominal incision (to extract the kidney), pelvic organ nociception, diaphragmatic irritation, ureteric colic, and urinary catheter discomfort. Although laparoscopic LDN is less painful than open LDN, both groups of patients will require patient-controlled analgesia (PCA) with fentanyl, epidural analgesia or both. New complementary anaesthetic techniques are currently being explored. Severe postoperative pain is an obvious disincentive for live kidney donation, so it is important to discuss this before the operation and have an agreed management plan, which will usually need to be multimodal. Epidural analgesia is ineffective for shoulder pain in laparoscopic LDN, and some surgeons prefer to avoid regional anaesthesia because of the perceived risk of hypotension and underperfusion. The most commonly used technique is currently i.v. fentanyl PCA. Opioid consumption can be decreased by topical local anaesthetic at the ports and renal fossa during surgery. Nonsteroidal antiinflammatory drugs (NSAIDs) are generally avoided because of concerns about potential nephrotoxicity. However, they provide good analgesia and cause less nausea and vomiting. To reduce the risk of nephrotoxicity, the patient should be kept well hydrated and the use of NSAIDs should be for a limited period only (up to 5 days after operation). If serum creatinine exceeds 176 mmol litre 21, NSAIDs should be avoided altogether. Paravertebral or abdominal field block (TAP block) can be used to complement analgesia and these are less likely to cause hypotension than neuraxial block. An indwelling catheter in the wound site delivering local anaesthetic infusion is currently gaining popularity, and current evidence suggests that it is safe and effective. Despite efforts to minimize postoperative pain, up to 5% of donors still experience chronic wound pain. 3 Mortality Risk of perioperative mortality is estimated to be %. This death rate is comparable with the risk of dying in a road traffic accident in 1 year in the USA (0.02%). Common causes include pulmonary embolism, hepatitis, myocardial infarction, and arrhythmias. 2 There have been at least two perioperative donor deaths in the UK. Morbidity Surgical complications occur in up to 20% of living donors, but only 1 2% are significant (delay in the patient s discharge from hospital). 6 Compare Figure 8. Donors usually experience a transient increase in serum creatinine level and halved creatinine clearance on the first postoperative day. These parameters usually return to normal within 1 month, although clinically asymptomatic microalbuminuria can persist and is seen in one in five donors. There is evidence that unilateral nephrectomy in healthy individuals does not have an adverse affect on long-term mortality (45 yr of follow-up). In total, 25 35% of patients will develop asymptomatic, non-progressive proteinuria. There is no convincing evidence that unilateral nephrectomy significantly increases the risk of hypertension. Because the remaining kidney tends to hypertrophy, long-term renal function remains at 75%. Conclusions Getting involved with the perioperative management of living kidney donors can be a highly satisfying and challenging experience for any anaesthetist. It requires a dedicated team that is aware of the uniqueness of the programme they are undertaking. Living kidney donation is a safe and low-risk procedure. Clinical complications related to kidney donation may be reduced by careful 320 Continuing Education in Anaesthesia, Critical Care & Pain j Volume 12 Number

5 pre-intervention selection and preparation of donors and by a lifelong follow-up of donors after donation. The institution of dedicated outpatient collaboration with general practitioners may be helpful to meet this aim. Furthermore, national and international registries are required to monitor health and long-term complications in donors. These programmes are destined to grow and in the future an increasing number of pre-emptive and unrelated transplants will be performed. New analgesic techniques, such as continuous infusion local anaesthetic catheters placed directly into the wound, are being developed and these will need to be evaluated for their use in these circumstances. Living donor organ donation has heralded a new age in transplant medicine and the management of ESRF. Its success depends as much on the abilities of the medical teams, as on the prevailing altruism surrounding us. Declaration of interest None declared. References 1. UK transplant website. Available from how_to_become_a_donor/living_kidney_donation/pdf/medical_informationyour_questions_answered.pdf 2. Human Tissue ACT Available from 3. Waller JR, Hiley AL, Mullin EJ, Veitch PS, Nicholson ML. Living kidney donation: a comparison of laparoscopic and conventional open operations. Postgrad Med J 2002; 78: National Kidney and urologic diseases Information Clearing house, a service of the national institute of diabetes and digestive and kidney diseases (NIDDK), NIH. Available from 5. Jankovic Z, Sri-Chandana C. Anaesthesia for living donor renal transplant: recent developments and recommendations. Curr Anaesth Crit Care 2008; 19: Renal Transplant Unit Handbook, Hammersmith Hospital NHS Trust, March Textor SC, Taler SJ, Driscoll N et al. Blood pressure and renal function after kidney donation from hypertensive living donors. Transplantation 2004; 78: Ratner LE, Ciseck LJ, Moore RG, Cigorroa FG, Kaufman HS, Kavoussi LR. Laparoscopic live donor nehprectomy. Transplantation 1995; 60: Tooher RL, Rao MM, Scott DF et al. A systematic review of laparoscopic live-donor nephrectomy. Transplantation 2004; 78: Please see multiple choice questions Continuing Education in Anaesthesia, Critical Care & Pain j Volume 12 Number