Anaesthetic Management of a Patient on Haemodialysis Posted for Surgery

Introduction

I. PREOPERATIVE ASSESSMENT & OPTIMIZATION

A. Timing of Dialysis

• Dialysis should be performed 24-48 hours before surgery (not on the same day), to:
  • Correct hyperkalaemia
  • Reduce uraemic coagulopathy
  • Optimize fluid balance (avoid acute hypovolaemia from dialysis)
  • Correct metabolic acidosis

B. Systems Review

1. Cardiovascular System (most common cause of death in ESRD)

• Hypertension - assess BP control; ACE inhibitors/ARBs are held on morning of surgery (risk of intraoperative hypotension)
• Ischaemic heart disease - ECG, echo, stress test if indicated
• Cardiomyopathy - uraemic or hypertensive; assess for LVH, diastolic dysfunction
• Pericardial effusion - uraemic pericarditis; risk of tamponade
• Accelerated atherosclerosis - peripheral and coronary
• Volume status: patients may be overloaded or hypovolaemic post-dialysis

2. Haematology

• Normochromic normocytic anaemia - Hb commonly 7-9 g/dL (erythropoietin deficiency + reduced RBC lifespan). Target Hb ≥10 g/dL preoperatively if possible (erythropoietin + IV iron)
• Platelet dysfunction - uraemia impairs platelet aggregation (not count). Bleeding time prolonged. Options to improve: dialysis, DDAVP (desmopressin 0.3 mcg/kg IV), cryoprecipitate, conjugated oestrogens
• Anaemia increases myocardial workload - assess cardiac reserve

3. Electrolytes & Metabolic

• Hyperkalaemia - most dangerous. K+ should be <5.5 mEq/L before surgery. Succinylcholine raises K+ by ~0.5-1 mEq/L and is CONTRAINDICATED if K+ >5.5 mEq/L
• Metabolic acidosis - compensated respiratory alkalosis; acidosis worsens hyperkalaemia, impairs myocardial contractility, causes vasodilation
• Hyponatraemia / dilutional - possible
• Hypocalcaemia / hyperphosphataemia - secondary hyperparathyroidism; calcium before induction if symptomatic
• Hypermagnesaemia - may potentiate neuromuscular blockade

4. Respiratory

• Pulmonary oedema from fluid overload
• Pleural effusions
• Kussmaul breathing (compensatory for acidosis)
• Aspiration risk increased (uraemic gastroparesis, delayed emptying) - consider RSI

5. Neurological / Endocrine

• Uraemic encephalopathy - confusion, obtundation, seizures
• Peripheral neuropathy - autonomic neuropathy causes haemodynamic instability
• Increased sensitivity to CNS depressants

6. Gastrointestinal

• Nausea, vomiting, delayed gastric emptying (uraemia)
• Full stomach precautions; consider H2 blocker or PPI + metoclopramide preoperatively

7. Airway

• No specific renal-related issues, but:
  • Uraemic pericarditis may cause cardiovascular instability on laryngoscopy
  • Aspiration risk (full stomach precautions)

C. Laboratory Investigations

• FBC, urea, creatinine, electrolytes (especially K+)
• ABG (assess acid-base)
• Coagulation profile, bleeding time
• Chest X-ray, ECG, echocardiogram
• Blood glucose (DM is a common cause of ESRD)

II. PREMEDICATION

• Use cautiously - uraemic patients are sensitive to CNS depressants
• Avoid long-acting benzodiazepines
• Midazolam (short-acting, hepatic metabolism) - acceptable in reduced dose
• H2 blockers (ranitidine) or PPI + metoclopramide for aspiration prophylaxis
• Continue antihypertensives except ACE inhibitors/ARBs on the day of surgery
• Avoid NSAIDs (further renal toxicity is not a concern in ESRD, but they worsen platelet function)

III. INTRAOPERATIVE MANAGEMENT

A. Monitoring

• Standard ASA monitoring: SpO2, ECG, NIBP, EtCO2, temperature
• Arterial line - for beat-to-beat BP monitoring and blood gas sampling (avoid the AV fistula arm)
• Central venous line - avoid subclavian (risk of pneumothorax, thrombosis); prefer internal jugular or femoral
• Urine output monitoring - limited utility in anuric patients, but watch for any residual output
• Temperature monitoring - hypothermia worsens coagulopathy
• Precautions with AV fistula arm: No BP cuff, no IV cannula, no arterial line on that arm. Protect with padding.

B. Induction

Intravenous Induction Agents

• Propofol - safe; hepatic conjugation; no active metabolites. Preferred induction agent. May cause hypotension - titrate carefully
• Thiopental - reduced plasma protein binding in uraemia (hypoalbuminaemia + reduced pH) increases free fraction; use reduced doses
• Ketamine - acceptable; may exacerbate hypertension (caution in poorly controlled HTN)
• Etomidate - useful in haemodynamically compromised patients; safe in renal failure

Rapid Sequence Induction (RSI)

• Preferred if aspiration risk exists (common in ESRD patients)
• Succinylcholine: can be used if K+ <5.5 mEq/L; raises K+ by ~0.5-1 mEq/L; avoid if K+ ≥5.5 mEq/L
• Rocuronium at 1.2 mg/kg** is the preferred RSI agent when succinylcholine is contraindicated (reversible with sugammadex)

C. Muscle Relaxants (Key Pharmacological Issue)

D. Opioids

E. Inhalational Agents

• Isoflurane, sevoflurane, desflurane - all acceptable
• Sevoflurane: produces Compound A (nephrotoxic in animal models); use fresh gas flow >2 L/min; avoid prolonged low-flow with sevoflurane in patients who still have residual renal function; in anuric ESRD patients this concern is less relevant
• Enflurane: metabolized to inorganic fluoride (nephrotoxic) - avoid

F. Fluid Management

• Critical issue: ESRD patients cannot excrete excess fluid
• Target euvolaemia; avoid overload
• 0.9% normal saline preferred over Ringer's lactate (which contains K+)
• Glucose-containing solutions may cause hyperglycaemia
• Monitor CVP or arterial waveform variation as fluid guides
• Blood transfusion: in anaemic patients, crossmatch and have blood available; transfuse if Hb <7-8 g/dL or haemodynamic instability

G. Regional Anaesthesia

• Excellent option when feasible (avoids systemic drug accumulation)
• Concerns: coagulopathy (platelet dysfunction) - check bleeding time/platelet function before neuroaxial block
• Epidural / spinal: safe if coagulation is adequate; hemodynamic effects more pronounced if patient is volume-depleted post-dialysis
• Avoid the AV fistula arm for all procedures

IV. POSTOPERATIVE MANAGEMENT

• Continued monitoring in HDU/ICU setting
• Reassess electrolytes (K+) post-op - surgery causes catabolism and K+ release
• Check for residual NMB - use train-of-four before extubation
• Pain management: use fentanyl PCA or paracetamol (safe); avoid NSAIDs; avoid morphine/pethidine
• Assess for fluid overload - postoperative fluid given by surgical team may accumulate
• Dialysis post-op if: hyperkalemia, fluid overload, severe acidosis, uremic symptoms
• Watch for:
  • Hyperkalaemia (catabolic state, blood transfusion, haematoma reabsorption)
  • Wound healing (impaired in uraemia)
  • Infection (immune dysfunction in ESRD)
  • Haemorrhage (platelet dysfunction)
• Restart regular haemodialysis schedule as soon as the patient is stable

V. SUMMARY TABLE: Drug Choices in ESRD

Key Points to Score Marks

1. Dialysis 24-48 hours before surgery - not same day
2. Check K+ before induction - succinylcholine contraindicated if K+ >5.5
3. Cisatracurium/atracurium are the NMBAs of choice (Hofmann elimination)
4. Fentanyl/remifentanil - safe opioids; avoid morphine (M6G accumulates) and pethidine (norpethidine seizures)
5. Protect the AV fistula arm - no BP cuff, no IV access
6. Platelet dysfunction - treat with DDAVP, dialysis, cryoprecipitate
7. Propofol preferred induction agent
8. Avoid Ringer's lactate (contains K+)
9. Postoperative HDU - watch for hyperkalaemia, fluid overload, residual NMB
10. Regional anaesthesia - consider when coagulation permits