Anesthesia in identical twins in December 23, 1954

Anesthesia for kidney transplantationKidney transplantation are the most commonly performed transplantation in USA, Europe and asia. First successful kidney transplantation was done in identical twins in December 23, 1954 with minimum monitors used BP cuff, ECG and recipient received spinal anaesthesia by Dr. Joseph Murray.The patient with ESRD posted for transplantation are a challenge to anaesthesiologist because of comorbidities associated with ESRD.Cardiovascular – Atherosclerosis, hypertension, CAD, arrhythmias, cardiomyopathy, congestive cardiac failure, pericarditis, pericardial effusionRespiratory – pulmonary edema, pleuritic, pleural effusion, pneumonia, atelectasis.Hematology – normocytic normochromic anaemia, dec platelet function due to accumulation of guanidine succinic acid inhibiting ADP induced platelet aggregationLiver – hepatitis, hypoalbuminemiaGastrointestinal – Peptic ulcer disease, nausea, vomiting, pancreatitisEndocrine – glucose intolerance, secondary hyperparathyroidismImmunological – impaired immunity and wound healingMusculoskeletal – renal osteodystrophy, metastatic calcificationNervous system – peripheral neuropathy, seizures, coma, autonomic neuropathyTherefore all patients suffering from ESRD CKD should undergo renal transplant unless absolutely contraindicatedIndications DiabetesGlomerulonephritisPyelonephritisPolycystic kidney diseaseObstructive uropathyCongenital urinary tract abnormalitiesAlport’s diseaseHypertensive nephrosclerosisReflux nephropathyInterstitial nephritisIgA nephropathyGoodpasture’s syndromeHemolytic uremic syndromeChemical nephrotoxicityRenal artery emboliSickle cell nephropathyContraindications absolute  -uncontrolled malignancy active hiv infection life expectancy <2 years due to other illness relative age > 0 yearsactive infectionchronic liver disease, cirrhosis, active hepatitisactive substance abuseactive TB, ATD therapyCOPDSevere diffuse atherosclerotic diseaseMorbid obesityPsychosocial or behavioral abnormalitiesmorbid obesityOutcome of renal transplant most cost effective method of treating ESRD, confers 40-60 % decrese in death rate compared with patient remaining on dialysisgraft survival rate in cadaver kidney and living kidney transplant recipient at 3 years >88% and 98% respectivelyTypes of kidney donors  – cadaveric and living donorCadaveric kidney donation – kidneys are last organs to be recovered in multiorgan recovery, after thoracic organs and liver have been retrived. Living kidneys donation – associated with higher sucess rate. assesment of donor renal function by nephrologist mandatoryadvisable to obtain psychiatric evaluation of the donors motivication, fitness and his ability to understand risk of the operationkidney removal through transperitoneal approach has a higher rate of splenic and intestinal complications(2-3%)  compared with other surgical approchesopen donor nephrectomy should be performed by an extraperitoneal approach through subcostal or dorsal lumbotomy incisionlaproscopic donor nephrectomy( either trans or retropertoneal) should only be performed by those trained in this specific procedure.absolute – age <18 yearsuncontrolled hypertensionDMprotenuria > 300 mg/24 hoursabnormal GFR rate compared to normal range for agemicroscopic hematuriahigh risk of thromboembolismmedically significant illensshistory of belateral kidney stonesHIV positive Relative – active chronic infection ( TB, Parasitic)obesitypsychiatric disordersANAESTHETIC MANAGEMENT OF LIVING DONORDonors safety is the prime concern of the anaesthesiologistPREOPERATIVE ASSESSMENT – Most of the donors belong to ASA I and II. Complete preanesthetic assessment should be performed including complete history, physical examination, laboratories studies with special attention to renal system  (complete hemogram, FBS/PPBS,urea/creatinine,serum electrolyte, LFT, coagulation profile , CXR,12 lead ECG and Echocardiography)SURGICAL TECHNIQUES FOR LIVING DONOR NEPHRECTOMY -Open living donor nephrectomy – transperitoneal or retroperitoneal approachlaparoscopic living donor nephrectomyhand assisted laparoscopic living donor nephrectomyrobot assisted  living donor nephrectomyANAESTHETIC MANAGEMENTGoals of anesthesia for living donor include  – Stable hemodynamics Avoidance of hypotension and hypovolemiaElimination of surgical stress response Maintenance of renal blood flowMaintain of urine output 2 ml/kg/hrAdequate  postoperative analgesiaMost commonly general anaesthesia with supplemental regional or local anesthesia is chosen.  Standard ASA monitoring is used including  Non invasive blood pressure monitoring, 5 lead ECG, ETCO2, SPO2, Temperature and urine output. Invasive monitoring is reserved for complicated donors including patients with comorbidities and obesity. invasive arterial line is placed before or after induction of anaesthesia. Patient is placed in lateral decubitus position with flexion of the table for adequate access to donor kidney. Special attention should to be taken during positioning to prevent pressure damage. Maintenance of adequate perfusion pressure and sufficient  fluid administration (10-20 ml/kg/hour) should be done with aim of maintaining a urine output of >2 ml/kg/hour. Mannitol 12.5-25 gram, given 15 minutes before clamping of renal artery is associated with improved kidney preservation. loop diuretic such as furosemide 20-40 mg can also be used. furosemide  maintains natriuresis,  decreases renal oxygen consumption by inhibition Na-K ATPase in the ascending limb of loop of henle and proximal convoluted tubule. protective interventions including atrial natriuretic peptide-analogues, dopamine adenosine antagonists and fenoldopam have also been tried.some centers recommend DVT prophylaxis in form of pneumatic compression devices and prophylactic LMWH as these patients are considered at moderate risk for DVT.Consideration for laparoscopic surgery – there are higher concerns for deterioration renal function in patients undergoing laparoscopic donor nephrectomy due to creation of pneumoperitoneum and increased intra abdominal pressure. IAP of 15-20mmhg has been shown to decrease GFR,renal blood flow and leads to transient decrease in urine output. increased IAP over 15mm hg can also lead to decreased cardio output which deacreses perfusion to the kidneys. the decrease in renal function during pneumoperitoneum depends on IAP, volume status of the patient, amount of hypercarbia and baseline renal function. our aim to offset this effect to maintain adequate renal perfusion pressure and adequate volume infusion. Borg et al recommended overnight infusion of crystalloid and bolus of colloid infusion before starting pneumoperitoneum which resulted in higher urine output. we should target a higher mean arterial  pressure during pneumoperitoneum to maintain adequate renal perfusion pressure. Postoperative painPostoperative pain management is important particularly in open surgery where pain from large incision interferes in breathing. pain at port sites and at incision for taking out kidney  is also experienced in cases of laparoscopic surgery. PCA with fentanyl is commonly used for pain control. other options include  thoracic paravertebral block, TAP block, epidural analgesia, intravenous paracetamol.NSAIDs are usually avoided because of concern regarding their potential nephrotoxicity. ANAESTHETIC MANAGEMENT OF KIDNEY RECIPIENTPREOPERATIVE CONSIDERATIONS Patients posted for renal transplant need to have a complete routine investigations done including  CBC, coagulation profile, LFT, RFT, ECG, Chest X-ray and echocardiography. all patients with ESRD need to be investigated for coronary artery disease particularly patients with diabetes mellitus. Dobutamine Stress Echocardiogram is particularly useful in high risk patients. Anaemia is a common problem in patients posted for renal transplant. However, these patients are used chronic low levels of Hb, so blood transfusion is rarely required. Recombinant erythropoietin (EPO) is widely used for patients of chronic renal failure leading to quick rise to target level of 10g/dl. EPO can lead to worsening of hypertension and increased incidence of cerebrovascular accidents( wiley). Need for preoperative dialysis should be assessed on the basis of metabolic and fluid abnormalities, with dialysis being performed within 24 hours  prior to surgery. Hypovolemia post dialysis should be avoided by keeping post dialysis weight near to the dry weight of the patient. These patients require gastric reflux prophylaxis using a H2 receptor antagonist, metoclopramide due to delayed gastric emptying because of stress, uremia, diabetes mellitus etc. magnesium and aluminum containing antacids should be avoidedAs these patients are more susceptible to infection because of immunosuppression and uremia, broad spectrum antibiotic should be administered prior to surgery. in case of presence of arteriovenous fistula, the said limb should not be used for fluid administration and the fistula should be carefully padded and patency should be checked intermittently throughout the procedure.  SURGICAL TECHNIQUES FOR KIDNEY TRANSPLANTATION -These include – Conventional Open kidney transplant – using an abdominal incision 15-25 cm in length.Minimal Incision Kidney Transplantation (MIKT) –  this uses a smaller 5-9 cm incision resulting in reduced requirement of postoperative analgesia and better cosmetic healing.Laparoscopic technique for kidney transplantation – first attempted in 2009 by rosales et al. using 7 cm incision for kidney placement and 3 extra port sitesRobotic technique for kidney transplantation.ANAESTHETIC MANAGEMENTCommonly general anaesthesia is used for renal transplantation although cases of renal transplantation under regional anaesthesia have been reported. standard ASA monitoring is recommended. High risk patients may require invasive monitoring in the form of CVP line and Invasive blood pressure monitoring. In patients with CAD and cardiomyopathies pulmonary artery pressure monitoring and transesophageal echocardiography may also be used. Rapid sequence induction is commonly used after proper preoxygenation as there patients are at increased risk of aspiration due to uremia, DM, autonomic neuropathy. These patients have low levels of albumin which increases the free fraction of drugs, uremia leads to disruption of blood brain barrier and hence there occurs an increase in level of unbound drugs crossing the blood brain barrier. Dose modification of drugs is essential also in view of volume status,  acid base status, and increased sensitivity of CNS to drugs. induction with thiopentone, propofol and etomidate using slow titrated doses is done. succinylcholine should be used with caution as it can lead to hyperkalemia, especially in patients with high initial potassium levels (>5 meq/l). For this reason non depolarizing muscle blockers are commonly used. Atracurium, Cisatracurium, vecuronium, rocuronium and mivacurium can be safely used. RSI may need to modified accordingly. short acting beta blockers like esmolol or short acting opioids like fentanyl or remifentanil should be used to prevent surge during laryngoscopy. Maintenance of anaesthesia can be achieved using either inhalation agents like isoflurane, sevoflurane, desflurane or intravenous propofol. Isoflurane is commonly considered agent of choice as minimal amount of it is metabolised and there is reduced production of fluoride ions, though studies have failed to show advantage of one agent over the other. analgesia can be maintained using fentanyl or remifentanil. morphine should be carefully used as morphine-6-glucuronide, its active metabolite can accumulate and can lead to respiratory depression. Perioperative fluid managementThe goal of perioperative fluid management is maintenance of adequate intravascular volume and sufficient perfusion to the transplanted kidney as hypotension due to depleted intravascular volume can lead to ATN which is a major factor in graft dysfunction. After removal of vascular clamp, 25% of blood volume is directed to the transplanted kidney, resulting in hypotension. There also occurs release of mediators from the ischemic kidney which cause vasodilation. These patients are prone due hypovolemia as a result of excess fluid removal during dialysis and due to perioperative fasting. This is masked in awake patients because of compensatory autonomic responses. Its traditionally recommended to maximize graft function by aggressive fluid management ( upto 30 ml/kg/h and cvp >15 mmhg) with caution in cardiac patients. A restrictive hydration regimen was shown by Gasperi et al with target CVP of 7-9mm hg of being equally effective in maintaining graft patency (crystalloids 2400 ± 1000 mL, 15 mL/kg/h). Some institutions recommend that change in CVP is more reliable for fluid administration, with a rise of > 7mm after fluid bolus indicating maximal intravascular volume. Generally its accepted to maintain a mean arterial pressure of more than 80 mmhg, CVP around 12 mm hg and Pulmonary artery pressure around 18-20 mm hg to maintain adequate perfusion to the kidney. TEE can also be used to monitor the intravascular volume, being a more reliable method to detect intravascular status of the patient than CVP.  SVV can also be used to monitor the requirement of fluid in a patient.CVP measurement are also unreliable in cases of laparoscopic renal transplant due to creation of pneumoperitoneum and trendelenburg position. This results in increase in CVP due to increase in intrathoracic pressure.Timing of fluid administration may also be important with othman et al compared a biphasic regimen maintaining a CVP of 5 mmhg in pre ischemic phase and 15 mmhg in ischemic phase with a constant infusion of 10-15 ml/kg/hour. They found better early graft function with biphasic regimen.Crystalloids are generally preferred for volume replacement as Normal saline can lead to hypochloremic acidosis. Petura et al compared 0.9% saline  with acetate buffered balanced crystalloid solution in patients undergoing renal transplant. They did not find any significant difference in incidence of hyperkalemia in the two groups and found lower percentage of patients required inotropes in balanced crystalloid group.Hadimioglu et al concluded that among the different crystalloids, plasmalyte cultivated  the best metabolic profile of the patients.To boost kidney function after completion of anastomosis, diuretics are given. these including  furosemide, mannitol. Mannitol induced osmotic diuresis and also has protective effect on tubular cells of transplanted kidney against ischemic injury. it enhances the release of  vasodilatory prostaglandins in the kidney and may also act as a free radical scavenger. 250 ml of 20% mannitol give immediately before vessel clamp removal reduces the incidence of ARF as indicated by lower requirement of post transplant dialysis. furosemide exerts its effects on thin ascending limb of henle. it also causes a decrease in renal o2 consumption by inhibiting Na-K ATPase. It is given during the vascular anastomosis to stimulate diuresis although it is unknown whether it is actually beneficial in improving early function. Dopamine infusion is controversial as it has not shown any benefit in studiesPostoperative pain managementchoice of intraoperative anaethesia influences the post operative pain control . patietns who recieved propfol had lower pain scores after surgery.PCA with fentanyl is commly used for post operative pain control. epidurals may be used carefully avoiding excessive vasodilation and hypotension. TAP and paravertebral blocks can also be used.