Perioperative Management of a Patient on Dialysis
A 70-year-old man on maintenance hemodialysis (3 times/week) is scheduled for elective coronary artery bypass grafting (CABG). His last dialysis was 2 days ago. He is on aspirin, clopidogrel, carvedilol, and amlodipine. Preop labs: K 5.8 mEq/L, BUN 60 mg/dL, creatinine 7.8 mg/dL, Hgb 9.5 g/dL, platelets 150k, INR 1.0. He is asymptomatic. The surgeon wants to proceed with surgery tomorrow.
1. What is your preoperative management plan?
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Preoperative management for a dialysis patient undergoing CABG: 1) Optimize volume status: he is likely hyperkalemic (K 5.8) and may be volume overloaded. He needs dialysis before surgery to correct hyperkalemia and volume. Ideally, dialysis should be performed the day before surgery (not the same day to avoid heparin effect). 2) Check potassium: 5.8 is high; dialysis will lower it. 3) Cardiac medications: continue beta-blocker and amlodipine. 4) Antiplatelet: clopidogrel may need to be stopped if bleeding risk, but for CABG, aspirin is usually continued. 5) Anemia: Hgb 9.5, may need transfusion? Usually threshold <8. 6) Arrange dialysis after surgery as needed. So plan: schedule dialysis the day before surgery, correct K, and proceed. Also, check for any other issues.
2. How would you manage his anticoagulation during surgery?
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During CABG, systemic heparinization is used. In dialysis patients, heparin can be used but needs monitoring. For the surgery, standard heparin dosing. Postop, he may need protamine reversal. Dialysis patients have increased bleeding risk due to platelet dysfunction. So use heparin with caution, monitor ACT. Also, avoid nephrotoxins. So anticoagulation: use heparin as per protocol, monitor ACT, and reverse with protamine if needed. Also, coordinate with nephrology for dialysis after surgery.