TRANSPLANTATION


ANESTHESIA FOR KIDNEY TRANSPLANTATION


Indications


•  Polycystic kidney disease


•  Diabetes mellitus–related kidney failure


•  Hypertensive kidney disease


•  Glomerular disease


•  Tubulointerstitial disease


•  Other familial or congenital diseases


Preoperative Evaluation


•  Check electrolytes the morning of surgery (delay surgery if K+ >6.0 mEq/L)


•  Should have dialysis within 24 hrs of surgery


•  Typical comorbidities


CAD = major cause of death in ESRD pts before & after transplant


Electrolyte abnl, HTN, DM, delayed gastric emptying, acidosis, anemia


CHF (from vol overload & compensatory concentric cardiomyopathy)


Coagulopathies (qualitative platelet defect in uremic pts), pericarditis


Intraoperative Management


•  Standard monitors (avoid placing BP cuff on fistula arm)


•  Consider A-line (if indicated by comorbidities)


•  Consider central line—CVP monitoring, ability to give thymoglobulin


May be difficult to place (prior dialysis lines)


Induction & Maintenance


•  Usually GA (RSI if gastroparesis suspected—i.e., long-standing diabetes)


•  Spinal & epidural not typically implemented (platelet dysfx in uremic pts)


•  Avoid enflurane & sevoflurane (inorganic fluoride byproduct may accumulate)


•  Paralytics


• Consider avoiding succinylcholine (may elev. K+ 0.5 mEq upon induction)


• Vecuronium & pancuronium may have prolonged effects


• Atracurium & cisatracurium not affected by ESRD (Hoffman degradation and nonenzymatic ester hydrolysis)


•  Narcotics


• Morphine, meperidine, oxycodone metabolites can accumulate & prolong duration


• Fentanyl, sufentanil, alfentanil, remifentanil may be safer alternatives


Surgical Procedure


•  8–10 cm arced incision from pubic symphysis to anterior superior iliac spine


•  Graft anastamoses usually made to external iliac vein & artery


External iliac artery & vein clamped for anastamoses


•  Graft warm ischemia time is usually about 15–30 min


•  Bladder filled via Foley catheter (to facilitate ureteral anastomosis to bladder)


•  Native kidney only removed if pt has intractable HTN or chronic infection


Specific Intraoperative Considerations


•  Hypotension may ensue with unclamping of iliac vessels & graft reperfusion


Avoid α-adrenergic agents that cause graft vessel vasoconstriction (phenylephrine)


Low-dose dopamine (3–5 mcg/kg/min) may be a better option


•  Heparin may be requested before clamping of iliac vessels


•  ↑ preload (CVP of 12–15 & MAP >60) before unclamping/reperfusion by administering 0.9 NS (3–5 L may be needed) or colloid


•  Mannitol may act as free radical scavenger & help diurese kidney after reperfusion (furosemide also used); goal urine output >0.5 mL/kg/hr


•  Ca-blocker admin before vessel anastomosis may prevent reperfusion injury


•  Consider bicarbonate infusion for significant metabolic acidosis (pH <7.2)


Immunosuppressive Agents


•  Typical combination: Corticosteroids, cyclosporine (or tacrolimus), & azathioprine (or mycophenolate mofetil)


•  Can delay cyclosporine & tacrolimus a few days & use antithymocyte globulin instead


Postoperative Management


•  Pt usually extubated


•  Goal urine output >0.5 mL/kg/hr



ANESTHESIA FOR LIVER TRANSPLANTATION (ALSO SEE CHAPTER 18, ANESTHESIA FOR GENERAL SURGERY)


General


•  1-yr survival following transplant 80–90%; 5-yr survival: 60–80%


•  Organ allocation: Based on MELD (model of end-stage liver dz) or PELD (pediatric) score


•  Increasing use of Non-Heart Beating Donation (NHBD), although still a small minority; also more use of extended donor criteria organs (age >70, DM, HTN, atherosclerotic heart dz) requiring more rapid reperfusion


Preoperative Evaluation


•  Underlying diagnoses of recipients


Hepatitis C (28%), EtOH (18%), cryptogenic cirrhosis (11%), primary biliary cirrhosis (9%), primary sclerosing cholangitis (8%), fulminant (6%), autoimmune (6%), hep B (4%), EtOH + hep C (4%), HCC (2%), metabolic (4%), other (4%)


•  Extrahepatic manifestations of liver disease: correctible problems include coagulopathy (platelet & FFP admin) pleural effusions (thoracentesis)



Intraoperative Management


•  Venous access


• Large-bore peripheral access (RICC line or 8.5 Fr peripheral IV)


• 8.5 or 9 Fr central venous catheter


• May need additional access if PA catheter is in lumen of 8.5 or 9 Fr central catheter


•  Standard monitors; A-line preinduction; CVP; consider PA catheter & TEE


•  Equipment


• Stat lab must be close by & available


• Rapid infuser systems (Level I, Belmont, etc.) set up & available


• Blood products available (usually 10 U FFP, 10 U PRBCs, & platelets)


• Venovenous bypass machine (with perfusionist) available


• Cell saver


Induction and Maintenance


•  Usually RSI (for “full stomach” precautions) or awake intubation


•  Pts often coagulopathic (use care when placing lines, ETT, NG tube)


•  Inhalational agents, narcotics, & muscle relaxants during maintenance


•  Avoid ketamine—can ↑ seizure activity


•  Moderate coagulopathy is permissible, provided there is no clinical bleeding


• Aggressive use of blood products may worsen outcome


• Conservative fluid management in selected patients


•  Maintain normothermia


Postoperative Management


•  Peripheral nerve injuries commonly due to positioning


•  Following skin closure, patient brought to ICU (usually intubated)



ANESTHESIA FOR LUNG TRANSPLANTATION


Indications


•  COPD, idiopathic pulmonary fibrosis, cystic fibrosis (CF), α1-antitrypsin deficiency, PPH (primary pulmonary HTN)


•  Terminally ill patients with end-stage lung disease


•  Less frequently: Sarcoidosis, retransplantation, Eisenmenger’s syndrome


Indications for Heart–Lung Transplantation (HLT)


•  Pts with lung transplant indication & significant left ventricular dz


•  Most commonly PPH, CF, & Eisenmenger’s syndrome


Single-Lung Transplantation (SLT) vs. Bilateral Sequential Lung Transplantation (BSLT)


•  BSLT = 1 lung transplanted (start with native lung with worse function) followed by a repeat procedure on contralateral side


Preoperative Evaluation


•  Lab values: ABO compatibility of donor & recipient


•  Radiography, echocardiography (RV failure)


• Functional data (including PFTs) & left heart cath (exclude CAD and intracardiac shunt)


•  Pts may have difficulty lying flat (poor pulm function)


Intraoperative Considerations


•  Standard monitors + A-line, central line, PA catheter; consider TEE (assess RV fx)


•  Lung isolation techniques (fiberoptic scope necessary)


•  2 large-bore IVs; ± epidural catheter


•  Be ready for emergent initiation of cardiopulmonary bypass


Induction and Maintenance


•  Lung isolation: Double-lumen tube, univent tube, or ETT + bronchial blocker


•  Avoid N2O (presence of bullous emphysematous dz, pulm HTN, intraop hypoxemia)


•  Fluid management usually conservative (helps with postop management)


•  Permissive hypercapnea


•  Be vigilant for cardiac instability or pneumothorax on nonoperative side


Surgical Procedure for Single-Lung Transplantation


•  Posterolateral thoracotomy position (need for rapid access to cannulation sites for emergent cardiopulmonary bypass may affect positioning)


•  Incision usually anterior thoracotomy with partial sternotomy


•  Sequence of surgical events:


1. Structures for lung to be resected are dissected free


2. Pneumonectomy completed


3. Bronchial anastomosis first, PA anastomosis, atrial/pulm vein anastomosis last


4. Pulmonary circulation flushed & ventilation begun


5. Process repeated for other side during bilateral sequential lung transplantation


Specific Anesthetic Considerations


• Lung recipients susceptible to pulm HTN & R ventricular dysfx during 1-lung ventilation


•  Hypoxemia common in 1-lung ventilation; consider using:


• FiO2 of 100%


• PEEP of 10 as tolerated to dependent lung


• CPAP to nondependent lung


•  Nitric oxide (NO)


• Advantages:


• ↓ pulm vascular resistance & improves oxygenation


• NO preferentially reaches ventilated areas, causing ↑ blood flow, improvements in V./Q. mismatch & improved oxygenation


• ↓ inflammatory response to surgery or trauma


• Impedes microbial growth


• Activates guanylate cyclase in platelets to attenuate platelet aggregation & adhesion


• Disadvantages:


• Methemoglobinemia, NO metabolite–related lung injury, ↓ sensitivity of exhaled N2O monitoring


• Rapid discontinuation of NO in pulm vasculature prevents systemic vasoconstriction & results in systemic hypotension


•  Cardiopulmonary bypass (CPB) indications


• Adequate oxygenation cannot be maintained despite ventilatory/pharmacologic interventions & PA clamping by surgeons


• Inability to ventilate


• Development of RV dysfx


• CI <2 L/min/m2, SvO2 <60%, MAP <50–60 mm Hg, SaO2 <85–90%, pH <7


•  May see hypotension with restoration of graft blood flow after anastomosis


•  At end of procedure, eval of pt for tube exchange to single lumen is performed, although high PEEP requirements & oropharyngeal edema may preclude it


ANESTHESIA FOR HEART TRANSPLANTATION


General Information


•  1-yr survival = 87%, 2-yr survival 78% from 1997–2004


•  Poor survival due to paucity of donor organs, devices (e.g., left ventricular-assist devices—LVAD) used to provide a bridge to transplant


Most Common Indications


•  New York Heart Association class III/IV heart failure (despite optimal therapy)


•  Heart failure survival scores high risk


•  Peak VO2 <10 mL/kg/min after anaerobic threshold


•  Severely symptomatic ventricular arrhythmias refractory to medical, ICD, surgical Tx


• Severely limiting ischemia unresponsive to interventional or surg revascularization



Perioperative Assessment


•  Donor heart function worsens with ischemic time >6 hrs


•  Pt usually not NPO (owing to short notice of graft availability)


•  Pt may receive extensive levels of cardiovascular support


• Meds—warfarin, vasopressor support, ACE inhibitor, dobutamine, milrinone


• Devices—LVAD, pacemaker/AICD, IABP


•  Immunosuppressive meds & antibiotics


•  Ensure blood products available


Intraoperative Management


•  Large-bore IV access, std monitors, preinduction A-line, CVP & PA catheter, TEE


•  Induction and maintenance


• Consider high-dose narcotic rapid sequence induction


• Also etomidate (0.3 mg/kg), fentanyl 1 mcg/kg), succinylcholine (15 mg/kg)


• Neuromuscular blockade with nondepolarizing agent


• May need inotropic support upon induction


• Standard heparin dosing for pre-CPB anticoagulation


• See Chapter 16, Anesthesia for Cardiac Surgery, for detailed notes on CPB


•  Separation from CPB


• Transplanted heart denervated (will not mount tachy-/bradycardic responses)


• Only direct-acting sympathomimetics work for inotropic/chronotropic effects


• Isoproterenol, epinephrine, milrinone, dobutamine


• LV function is generally adequate, however, RV dysfunction often seen


• Strategies to lower PVR


• High FiO2; avoid hypercapnia/hypothermia


• Optimize airway pressures & tidal volumes


• Use nitrates, PGE1, prostacyclin, & inhaled NO as indicated


• Use CVP/TEE to guide fluid management


• Consider use of RV assist device


Surgical Procedure


•  Incision median sternotomy


•  Aortic cannulation high, near the arch


•  Recipient heart excised (except for L atrial tissue with pulmonary veins)


• Biatrial approach—excises both atria (mandating bicaval anastomosis)


• Classic approach—atria transected at grooves


Specific Anesthetic Considerations


•  Anticipate previous cardiac surgery (redo sternotomy)


• Structures may be adhesed to sternum & ruptured upon entry


• Presence of LVAD/RVAD


•  Pts with hemodynamic instability may need extracorporeal membrane oxygenation (ECMO) prior to induction


•  Immunosuppressive agents need to be given including methylprednisolone 500 mg as last anastomosis is being completed


•  No specific anesthetic strategies for posttransplant anesthesia delivery


• May see a delayed response to catecholamines


• Anticipate a denervated heart with absence of vagal tone


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Aug 28, 2016 | Posted by in ANESTHESIA | Comments Off on TRANSPLANTATION

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