11.2 CKD Organ systems Pharmacology and Pain Flashcards
You are asked to anaesthetise a patient with chronic kidney disease (CKD; stage ≥4).
a) List organ system effects
that must be considered. (40%)
A+B
Issues relate to:
» CKD itself.
> > Underlying cause of the CKD.
> > Management of CKD.
> > Implications of possible previous transplant
Airway:
» Some causes of CKD may
contribute to a difficult airway,
e.g. scleroderma.
Respiratory:
» Assess for fluid overload.
> > Patient may be immunosuppressed
due to drugs or disease –
assess for possibility of respiratory infection.
> > Continuous ambulatory
peritoneal dialysis (CAPD) fluid
should be drained preoperatively
as it may cause diaphragmatic
splinting, basal atelectasis, shunt.
You are asked to anaesthetise a patient with chronic kidney disease (CKD; stage ≥4).
a) List organ system effects
that must be considered. (40%)
C
Cardiovascular:
> > Patients with CKD at risk of accelerated coronary artery disease. Assess symptoms, check recent ECG.
> > Hypertension may be underlying cause or result from CKD. Check for end-organ damage in the form of left ventricular hypertrophy on ECG and echo.
> > Fistulae/vascaths must be preserved. Do not cannulate or take blood pressure on fistula arm, avoid pressure on it intraoperatively.
> > At risk of calcified valvular lesions resulting in stenosis – assess symptoms, auscultate heart sounds, echo if indicated.
> > Up-to-date ECG, echo and exercise testing should be done in work-up for transplant list.
You are asked to anaesthetise a patient with chronic kidney disease (CKD; stage ≥4).
a) List organ system effects
that must be considered. (40%)
Neuro
Endo
Neurological:
» Autonomic neuropathy related to uraemia and diabetes mellitus.
Risk of delayed gastric emptying and
possible need for proton pump inhibitor
premedication and rapid sequence induction.
Endocrine:
» If patient has diabetes mellitus, use variable rate insulin infusion.
> > In the absence of diabetes, the patient may still have impaired glucose tolerance due to steroid treatment.
> > If having steroid treatment, may need perioperative supplementation.
> > Patient may have secondary hyperparathyroidism: check calcium and phosphate levels.
You are asked to anaesthetise a patient with chronic kidney disease (CKD; stage ≥4).
a) List organ system effects
that must be considered. (40%)
Pharmacology:
Pharmacology:
» Suxamethonium for rapid sequence induction may be contraindicated in the presence of elevated serum potassium.
> > Variable rate insulin infusion if diabetic, or management of oral hypoglycaemic agents according to AAGBI guidelines.
> > Omit angiotensin converting enzyme inhibitor or angiotensin II receptor antagonist prior to surgery to avoid hypotension.
All other antihypertensives to be continued.
> > If patient has previous transplant, may be taking steroids and other immunosuppressive drugs
(e.g. tacrolimus, cyclosporin).
Even if transplant has failed, these drugs need to remain therapeutic to avoid rejection, so seek advice from renal physicians regarding dosing perioperatively, whilst nil by mouth.
You are asked to anaesthetise a patient with chronic kidney disease (CKD; stage ≥4).
a) List organ system effects
that must be considered. (40%)
Gastrointestinal:
Haematological:
Gastrointestinal:
» Consider autonomic neuropathy due to chronic kidney disease (or diabetes mellitus).
Premedication with proton pump inhibitor and rapid
sequence induction should be considered.
Haematological:
» May have anaemia due to a variety of underlying reasons: chronic disease, impaired erythropoiesis, blood loss from dialysis, gastrointestinal loss.
> > Check full blood count, ensure up-to-date group and save.
> > Thrombocytopathy associated with renal failure may contraindicate regional anaesthesia, but this is improved by dialysis and therefore unlikely to be an issue.
You are asked to anaesthetise a patient with chronic kidney disease (CKD; stage ≥4).
Organ systems
Immune, infection:
Immune, infection:
» Susceptible to infection due to immunosuppression of disease state and/ or drugs.
Check white cell count;
consider urinary tract,
respiratory system,
and vascular or
peritoneal access as
possible sources of infection.
Renal:
» Assess fluid status.
Some patients with CKD are anuric,
some still pass urine.
Ensure patient is not hypovolaemic if recent haemodialysis as this increases risk of perioperative hypotension.
> > Check electrolytes –
may require haemodialysis preoperatively.
Abnormalities predispose to arrhythmia
b) Outline pharmacological factors
that must be considered. (30%)
> > Hypalbuminaemia and acidosis
increase free drug availability and
volume of distribution:
reduce benzodiazepine,
barbiturate and propofol doses.
Reduce local anaesthetic dose by 25%.
> > Elimination of highly ionised lipid
insoluble drugs dependent on renal
excretion
(but single-dose duration limited by redistribution).
Affects penicillin, cephalosporins, neostigmine, salicylates.
b) Outline pharmacological factors
that must be considered. (30%)
> > Morphine, pethidine and benzodiazepines are hepatically metabolised to a water soluble form for excretion by kidneys.
Active metabolites may accumulate with repeated dosing
(such as morphine-6-glucaronide and norpethidine) with consequent respiratory depression and reduced
consciousness.
Remifentanil and fentanyl may be safely used
b) Outline pharmacological factors
that must be considered. (30%)
> > Metabolism of sevoflurane and enflurane – theoretical risk from nephrotoxic fluoride ion production. Only a consideration if anaesthesia
very prolonged.
> > Vecuronium and rocuronium (partially) renally excreted. Duration of action not increased with single dose but prolonged neuromuscular blockade
may occur with repeated or very large doses.
> > Hyperkalaemia may contraindicate suxamethonium use.
b) Outline pharmacological factors
that must be considered. (30%)
> > Avoid nephrotoxins,
especially in the perioperative period,
when the patient may be exposed to other factors such as hypotension and dehydration that cause renal damage:
angiotensin converting enzyme inhibitors,
angiotensin II receptor antagonists,
gentamicin,
NSAIDs,
contrast media.
> > Patient is likely to be on multiple medications,
the effects of which must be considered:
antihypertensives,
diuretics,
insulin or
other hypoglycaemic agents.
b) Outline pharmacological factors
that must be considered. (30%)
> > If the patient has had a previous transplant (now failing), may be taking steroids and other immunosuppressive drugs (e.g. tacrolimus,
cyclosporin). These drugs need to remain therapeutic to avoid rejection, so seek advice from renal physicians regarding dosing perioperatively, whilst nil by mouth.
> > May require steroid supplementation due to previous or current steroid treatment.
> > Patient may be anticoagulated due to recent heparin administration for haemodialysis.
c) How may this patient’s
postoperative pain be optimally
managed? (3 marks)
> > Regular pain assessment and management of anxiety through explanation and reassurance.
> > Regular paracetamol.
> > NSAIDs contraindicated due to effect on renal perfusion.
> > Wound catheters.
> > PCA: fentanyl and oxycodone
do not accumulate in renal failure (graft
may not function immediately).
> > Epidural: used in some centres, may be contraindicated by recent
heparin administration for dialysis. Need to ensure that hypotension does
not result.
