Peri-operative management of the dialysis patient

Pelonomi: Firm 4Consultant: dr FlooksRegistrar: A vd Horst

Our patient

• 49yr lady from Rocklands• Hypertensive nephropathy on chronic

haemodialysis

• Anterior abdominal wall mass ? Desmoid tumor

• Excision biopsy

Special investigations

Na 135 Cor Ca 3.10K 3.2 Mg 0.76Ur 3.0 P 0.63 Cr 214

Liverfunctions: albumin 22 tot protein 76 rest normal

Special investigations

• FBC: wcc 8.4 x 109/ℓ

Hb 8.0g/dℓ mcv 88.9fl pl 416 x 109/ℓ

• Iron studies: serum iron 5.4ųmol/ℓ transferrin 0.7g/ℓ TF saturation 31%

Peri-operative management of the dialysis patient

Increased morbidity and mortality

• High incidence of CAD and myocardial dysfunction

• Difficulty in managing fluid and electrolytes - potassium

• Inability to metabolize and excrete anaesthetic and analgesic agents

• Bleeding complications• Poor BP control: both hypo – and hypertension

Issues of concern

1. Baseline lab evaluation2. Anaemia3. Nutritional status4. Dialysis dose5. Fluid and electrolyte management6. BP control7. Evaluation for cardiovascular disease8. Correction of bleeding diathesis9. Antibiotics10. Glucose metabolism11. IV access12. Anaesthetic considerations

1. Laboratory evaluation• Baseline investigations: - electrolytes, urea and creatinine - glucose - albumin - full blood count - coagulation profile - iron studies if anaemic - drug levels - digoxin

2. Anaemia status• Elective surgery: Hb 12-13g/dℓ• Erythropoiesis stimulating agents (ESA)

Important, because post – operatively: • transfusions are often needed due to blood loss

intra-operatively

• ESA – resistance

3. Nutrition

• Ability to heal post-surgery • Protein catabolic rate and albumin should be

optimalized• Stop drugs decreasing appetite• Drugs to ameliorate gastroparesis• Nutritional supplements

4. Intensive dialysis

• Unknown whether delivery of intensive doses of dialysis prior to or during surgery improves outcome (Uptodate)

• Discussion between the anaesthetist and the nephrologist

5. Fluid and electrolyte management

• Optimal volume status: estimation of the amount of fluid lost and administered during surgery

• Normal saline vs Ringer’s lactate

• Electrolytes – calcium and potassium

Hyperkalemia and emergency surgery

• ECG – asses the physiological effect of hyperkalemia

• Chronic renal failure patients – increased tolerance

• ECG changes due to alteration in transcellular K⁺ gradient and not the absolute value

• CRF – increased total body and intracellular K⁺ = normal ECG

Course of action is basedon the clinical setting

If: • no ECG changes, • stable patient, • K⁺ 6 – 6.2 mmol/ℓ == cont surgery

If : • ECG changes present = dialysis

If no dialysis facilities available:

• Medical treatment - Calcium - Insulin and dextrose - Sodium bicarbonate - β-stimulants - Cation exchange resins - can be give PR if NPO - potential for post-op intestinal necrosis

6. Blood pressure control

Hypertension

1. Optimize volume status – optimal dry weight 2. Parenteral antihypertensives: labetolol, hydralazine ( with β – blocker) diltiazem, nitroglycerine, nitroprusside 3. Post-op – normal oral antihypertensive regimen, with close monitoring

Hypotension

1. Excessive fluid removal2. Left ventricle dysfunction3. Autonomic dysfunction4. Pericardial tamponade5. Vasodilatation from opioids / anxiolytics

= Titration of anti-hypertensive treatment

7. Cardiovascular evaluation

• 50% of dialysis patients have CVS disease • American College of Cardiology / AHA

• Risk stratification

8. Bleeding tendency

• Increased tendency to bleeding

• Platelet dysfunction – uremia, anemia, hyperparathyroidism, aspirin• Bleeding time not recommended as screening

test pre-op, except for renal biopsy and major vascular surgery

• Raising hkt, desmopressin, cryprecipitate, dialysis, estrogen

9. Peri-operative antibiotic use

• In accordance with general surgical guidelines

• Dose adjustments• Loading dose unchanged

• Access procedures - fewer access infections

10. Glucose metabolism

• Better control @ home, than in hospital

- change in physical activity - acute comorbid conditions - inability to ingest food - reality of surgery schedules

• Type 1 DM – brittle - wide variations in glucose metabolism - serum ketones if DKA

• Type 2 DM – induction of hyperglycemia - increased t½ of oral drugs

11. IV access

• Frequent IV lines may destroy future access sites

• Avoid subclavian central lines = subclavian stenosis

• CVP should not be placed on the same side as the AV access

12. Anaesthetic considerations

• Thiopental – doubled free fraction

• Ketamine – hypertension

• Propofol – hepatic metabolism - well tolerated

• Succinylcholine – Hyperkalemia - K < 5mmol/ℓ - succinylmoncholine

• NDMR: pancuronium and gallamine renally excreted = prolonged paralysis atracurium, vercuronium

• Sedatives: benzo’s are protein bound = free fraction in CRF intermediate metabolites

Analgesia

• Opioids – fentanyl drug of choice - avoid pethidine, propoxyphene

- effects of morphine prolonged - half-life of metabolites prolonged

• Paracetamol can be used without any dose adjustments

In short

In short

Peri-operative management of the dialysis patient requires a focussed assessment of all 12 aspects, as well as careful liaison between the physician, surgeon and anaesthetist.

Back to our patient

• She underwent surgery without any complications.

• Histology: Lipoma

Thank you

Bibliography

• Uptodate• Miller’s Anesthesia, 6th edition