In a patient with end‑stage renal disease on renal replacement therapy, hypertension, and coronary artery disease who is scheduled for retinal surgery, what preoperative studies are indicated?

Preoperative Studies for ESRD Patient on RRT Undergoing Retinal Surgery

For a patient with ESRD on renal replacement therapy, hypertension, and CAD scheduled for retinal surgery, obtain the following preoperative studies: complete blood count, comprehensive metabolic panel (including electrolytes, BUN, creatinine), coagulation profile (PT/INR, platelet count), ECG, and cardiac troponin levels. 1, 2

Essential Laboratory Studies

Hematologic and Metabolic Assessment

• Complete blood count to evaluate for anemia (common in ESRD due to decreased erythropoietin) and thrombocytopenia, both of which increase surgical bleeding risk 1, 2
• Serum electrolytes with particular attention to potassium levels, as hyperkalemia poses significant perioperative cardiac risk in dialysis patients 1, 2
• Blood urea nitrogen and creatinine to assess current renal function status 1
• Calcium, magnesium, phosphate, and bicarbonate levels to evaluate metabolic bone disease and acid-base status 1

Coagulation Assessment

• Bleeding time measurement is critical, as values >10-15 minutes indicate high hemorrhage risk in ESRD patients due to platelet dysfunction 1
• Prothrombin time and platelet count should be checked preoperatively in all intermediate- and high-risk patients 1
• If platelet count is <50,000/mm³, platelet transfusion should be considered 1

Cardiovascular Evaluation

Cardiac Risk Assessment

• 12-lead ECG is indicated for all intermediate- and high-risk patients undergoing surgery 1
• Cardiac troponin levels should be measured preoperatively and at 24 and 48 hours postoperatively in intermediate- and high-risk patients, as this population has elevated cardiovascular mortality 1
• Given the patient's CAD, a preoperative risk assessment for ischemic heart disease should be performed 1

Blood Pressure Monitoring

• Vital signs including blood pressure and heart rate should be checked within 2 hours preoperatively 1
• Blood pressure should be well-controlled (consistently <180/110 mm Hg) before proceeding with surgery 1, 3

Dialysis-Specific Considerations

Timing and Access Evaluation

• Dialysis should be performed the day before surgery to optimize fluid and electrolyte balance 2
• Examine the dialysis access (arteriovenous fistula or graft) for signs of infection and assess patency 2
• Additional dialysis sessions prior to surgery do not improve outcomes and are not recommended 2

Functional Status Assessment

• Functional capacity evaluation using the two-flight of stairs test or Duke Activity Status Index (DASI) should be performed preoperatively 1

Critical Pitfalls to Avoid

Medication Management

• Discontinue ACE inhibitors and ARBs 24 hours before surgery to reduce risk of severe intraoperative hypotension and hemodynamic instability 3, 2
• Hold diuretics on the day of surgery to prevent volume depletion and electrolyte disturbances 3
• Continue beta-blockers perioperatively if the patient is already taking them chronically to prevent rebound hypertension 1
• Never start beta-blockers on the day of surgery in beta-blocker-naïve patients, as this is potentially harmful 1

Electrolyte Correction

• Correct hypokalemia and hypomagnesemia before surgery to reduce risk of perioperative arrhythmias, as hypokalemia occurs in up to 34% of surgical patients and increases ventricular arrhythmia risk 3

Glycemic Control

• For diabetic ESRD patients, ensure adequate glycemic control preoperatively, as this population has particularly high perioperative risk 2, 4

Additional Considerations

Antibiotic Prophylaxis Planning

• Review antibiotic allergy history, as prophylactic antibiotics will be needed with dose adjustments based on renal function 1
• For penicillin-allergic patients, alternative regimens must be planned in advance 1

Anesthesia Considerations

• Document any history of adverse reactions to anesthesia 4
• Note that local anesthetics like lidocaine and mepivacaine can be safely used, but epinephrine doses should be reduced due to hypertension 1