Renal failure

‫اﺣﻣد ﺣﺳن راﺿﻲ‬.‫د‬

 kidneys
• The kidneys play a central role in excretion of many metabolic breakdown
products, including ammonia and urea from protein, creatinine from
muscle, uric acid from nucleic acids, drugs and toxins.
• They achieve this by making large volumes of an ultrafltrate of plasma
(125mL/min, 180L/24 hrs) at the glomerulus, and selectively reabsorbing
components of this ultrafltrate at points along the nephron
• Each kidney contains approximately 1 million individual functional units,
called nephrons.
• Under normal circumstances, approximately 99% of the 180L of glomerular
filtrate that is produced each day is reabsorbed in the tubules
 Glomerular filtration rate
• The glomerular filtration rate (GFR) is the sum of the ultrafiltration
rates from plasma into the Bowman’s space in each nephron and is a
measure of renal excretory function
• The normal range of GFR, is 100–130 average of 125 mL/min in
men
• and 90–120 ml/min in women younger than the age of 40.
 1.Acute kidney injury (AKI)

(AKI) is a sudden and often reversible loss of renal function, which

develops over days or weeks and is often accompanied by a reduction in
urine volume.
Approximately 7% of all hospitalized patients and 20% of acutely ill
patients develop AKI
In uncomplicated AKI mortality is low, however when it is associated with
sepsis and multiple organ failure mortality is 50%–70% and the outcome
is usually determined by the severity of the underlying disorder and other
complications, rather than by kidney injury itself
 Pathophysiology
• ‘Pre-renal, when perfusion to the kidney is reduced
•‘Renal’, when the primary insult affects the kidney itself
• ‘post-renal’, when there is an obstruction to urine flow at
any point from the tubule to the urethra.
 Clinical features
•.
• Early recognition of AKI, is required to prevent rapid progression of
renal injury and to facilitate recovery as the damage may be potentially
reversible if detected at an early stage. Pre renal
• Low BP relative to normal for the patient (including postural drop)
• Tachycardia
• Weight decrease
• Dry mucous membranes
• Decreased skin turgor
• JVP not visible even when lying down.
• nausea or vomiting
• shortness of breath
• confusion • tiredness • reduction in urine output
• water retention
•Renal AKI
• Vital signs , Fluid assessment, Oedema
• Purpuric rash, uveitis, arthritis
• Fever
• Rash

•Post renal
• Rectal examination (prostate and anal tone)
• Distended bladder
• Pelvic mass
 Diagnosis
• Pre-renal
• Fractional excretion Na < 1%
• High serum urea: creatinine ratio
• Urinalysis
• Renal
• Proteinuria, haematuria
• Red cell casts, dysmorphic red cells
• Leucocyturia
• White cell casts
• Minimal proteinuria
• Post-renal
• Urinalysis frequently normal (may reveal haematuria depending on cause)
• Renal ultrasound (hydronephrosis
 Management of acute kidney injury
• Assess fluid status as this will determine fluid prescription:
• If hypovolaemic: optimize systemic hemodynamic status with
fluid
• Once euvolaemic, match fluid intake to urine output plus an
additional 500mL/24 hrs to cover insensible losses
• If fluid-overloaded, prescribe diuretics (loop diuretics at high
dose will often be required); if the response is unsatisfactory,
dialysis may be required
•
Cont.
• Treat underlying cause
• If K+ > 6.5 mmol/L and ECG changes of hyperkalaemia are
present administer calcium gluconate to stabilise myocardium,
lower potassium by oral potassium exchange resin to prevent
potassium absorption, or administering intravenous glucose/insulin or
sodium bicarbonate to move potassium intracellularly.
• These are holding measures until a definitive method of removing
potassium is achieved (restoration of renal function or dialysis)
Cont.
• Discontinue potentially nephrotoxic drugs and reduce doses of
therapeutic drugs according to level of renal function

• Ensure adequate nutritional support

• Consider proton pump inhibitors to reduce the risk of upper

gastrointestinal bleeding

• Screen for intercurrent infections and treat promptly if present

 Recovery from AKI
• Most cases of AKI will recover after the insult resolves but
recovery may be impaired in those with pre-existing CKD or
following a prolonged, severe or irreversible insult.
• Recovery is heralded by a gradual return of urine output and a
steady reduction in serum creatinine.
• There is often a diuretic phase in which urine output increases
rapidly and remains excessive for several days before returning
to normal
 2.Chronic kidney disease
• Chronic kidney disease (CKD) refers to an irreversible deterioration in
renal function that usually develops over a period of years.
• Initially, it manifests only as a biochemical abnormality but,
eventually, loss of the excretory, metabolic, and endocrine functions of
the kidney leads to the clinical symptoms and signs of renal failure,
collectively referred to as uremia.
• When death is likely without RRT (CKD stage 5), it is called end-stage
renal disease (ESRD)
 Epidemiology
• The social and economic consequences of CKD are
considerable.
• In many countries, estimates of the prevalence of CKD stages
3–5 (eGFR <60 mL/min) are around 5%–7%, mostly affecting
people aged 65 years and above.

• clinical features markers of CKD such as anemia, elevated PTH,

and small kidneys observed on imaging
Common causes of chronic kidney disease
• Diabetes mellitus 20%–45% Large racial and geographical
differences
• Interstitial diseases 20%–30% Drug-induced, reflux nephropathy

• Glomerular diseases 10%–20% IgA nephropathy is most common

• Hypertension 5%–20% Causality controversial, much may be

secondary to another primary renal disease
Cont.
• Systemic infammatory diseases 5%–10% Systemic lupus
erythematosus, vasculitis
• Renovascular disease 5% Mostly atheromatous, may be more
common

• Congenital and inherited 10% Polycystic kidney disease,

• Unknown 5%–10
investigations in chronic kidney disease
 Management

• The aims of management in CKD are to:

• monitor renal function
• Renal function should therefore be monitored every 6 months in
patients with stage 3 CKD, but more frequently in patients who
are deteriorating rapidly or have stage 4 or 5 CKD
•prevent or slow further renal damage
• Therapies directed towards the primary cause of CKD should be
employed where possible; tight blood pressure control is
applicable to CKD regardless of cause, however, and reducing
proteinuria is a key target in those with glomerular disease.
Maintenance of fluid and electrolyte
balance
• Urea is a key product of protein degradation and accumulates
with progressive CKD.
• All patients with stages 4 and 5 CKD should be given dietetic
advice aimed at preventing excessive consumption of protein.
• . Potassium often accumulates in patients with advanced CKD,
who
• should be provided with dietary advice to reduce daily
potassium intake to below 70 mmol
• Consideration should be given to stopping or reducing drugs
that elevate potassium, such as potassium-sparing diuretics and
ACE inhibitors/ARBs
Cont.
• limit complications of renal failure
• Anaemia is common in patients with CKD and contributes to
many of the non-specific symptoms, including fatigue and
shortness of breath.
• Once iron deficiency and other causes of anaemia have been
excluded or corrected, recombinant human erythropoietin is
very effective in correcting the anaemia of CKD and improving
symptoms
• treat risk factors for cardiovascular disease
• prepare for RRT, if appropriate
 Renal replacement therapy
• Renal replacement therapy (RRT) may be required on a
temporary basis in patients with AKI or on a permanent basis for
those with advanced CKD.
• Since the advent of long-term RRT in the 1960s, the number
ofpatients with ESRD who are kept alive by dialysis and
transplantation has increased considerably
 1.Hemodialysis

•Haemodialysis is the most common form of dialysis

employed in ESRD and is also used in AKI.
• Haemodialysis involves gaining access to the
circulation, either through a central venous catheter or
an arteriovenous
fistula or graft.
 2.Peritoneal dialysis
• Peritoneal dialysis is principally used in the treatment of CKD,
though it may occasionally be employed in AKI.
• It requires the insertion of a permanent Silastic catheter into the
peritoneal cavity.
 3. Renal transplantation
• Renal transplantation offers the best chance of long-term
survival in ESRD and is the most cost-effective treatment.
• All patients with ESRD should be considered for transplantation
but many are not suitable due to a combination of comorbidity
and advanced age (although no absolute age limit applies).
• Active malignancy, vasculitis and cardiovascular comorbidity are
common contraindications to transplantation, with risk of
recurrence of the original renal disease.
Activity
•How do you deal with uraemic patients during
anesthesia?
Thank you