Download AKI - UHCW Medical Education

Acute Kidney Injury (AKI)
Dr Svitlana Zhelezna
Clinical Teaching Fellow
UHCW NHS Trust
[email protected]
2013/2014 academic year
Objectives:
Recognise AKI
 Investigate and decide on: pre-renal,
renal and post renal causes
 Recognise and manage hypovolemia
 Manage hyperkalemia
 Indications for emergency dialysis
and heamofiltration

Case 1
66 y.o. man presents to A&E at 10 am
 PC: increasing SOB for 7/7, coughing up phlegm and
having fever.
 PMH: DM, HTN
O/E: pale, sweaty, BP 85/50, HR 115, Sats 92% on air, RR
25, T 38.3, coarse crackles on the right side of his chest.
 CXR - RLL pneumonia.
 Blood results: Na 130, K 4.5, Urea 14.3, Cr 189

The nurse asks you to reassess the patient at 2 pm as he
hasn't passed urine since admission.
Current obs: HR 95, BP 95/55, Sats 96%, RR 22, T 37.5
What would be your actions?
Medical management
Pt’s cardex:
Stat: paracetamol 1g IV
Oxigen 6 L
Regular:
Enoxaparin 40 mg

metformin, aspirin, ramipril, atenolol and simvastatin
Nebs with Soduim Chloride 0.9%
Abx: Co-amoxiclave 1.2 g and Clarithromycin 500mg
PRN: paracetamol 1g PO/IV, not more than QDS
Salbutamol 2.5-5 ml nebs
Definition of AKI (Kidney Disease:
Improving Global Outcomes (KDIGO))



Acute kidney injury is defined when one of the
following criteria is met
Serum creatinine rises by ≥ 26µmol/L within 48
hours
Serum creatinine rises ≥ 1.5 fold from the
reference value, which is known or presumed to
have occurred within one week
urine output is < 0.5ml/kg/hr for >6 consecutive
hours
Examples:
Mr Smith U&E
Date
14/06/14
Cr
Mrs Dale
Date
15/06/14
16/06/14
77
89
109
09/06/14
15/06/14
Cr
89
135
Mr Hob (approximate weight 80 kg) - 40 ml per hour
cut off – less then 240 ml per 6 hours
Statistics:


The reported prevalence of AKI from US data
ranges from 1% (community-acquired) up to
7.1% (hospital-acquired) of all hospital
admissions
The incidence of AKI requiring renal
replacement therapy (RRT) ranges from 22
per million population/year (pmp) to 203
pmp/year
Symptoms of Acute Kidney Injury:
Raised Urea, Creatinine and Uric Acid:
- Confusion
- Drowsiness
Failure to Excrete Normal Acidic Products:
- Metabolic Acidosis
- Respiratory Hyperventilation
Electrolyte Imbalances (Hyperkalaemia):
- Dysrhythmias
KDIGO staging system for
acute kidney injury
Stage
Serum creatinine (SCr)
Urine output criteria
1
increase ≥ 26 μmol/L within 48hrs or <0.5 mL/kg/hr for > 6
increase ≥1.5 to 1.9 X reference SCr consecutive hrs
2
increase ≥ 2 to 2.9 X reference SCr
<0.5 mL/kg/ hr for > 12 hrs
3
increase ≥3 X reference SCr or
increase ≥354 μmol/L or
commenced on renal replacement
therapy (RRT) irrespective of stage
<0.3 mL/kg/ hr for > 24 hrs
or anuria for 12 hrs
AKI risk factors:







age > 75 yrs
chronic kidney disease (CKD, eGFR < 60
mls/min/1.73m2)
Cardiac failure
Atherosclerotic peripheral vascular disease
Liver disease
Diabetes mellitus
Nephrotoxic medications
Potential causes for AKI including
reduced fluid intake
 increased fluid losses
 urinary tract symptoms
 recent drug ingestion
 sepsis

What to look for when clerking ?
Ask about:
 family history of renal disease
 exactly when the presenting symptoms started,
and which came first
 joint pains, or rash, or nose bleed, or ear trouble
(vasculitis)
 backache or bone pains (myeloma and other
malignancy)
 drugs taken (NSAID, ACEI ect.)
Assessment of volume status:









Core temperature (raise due to dehydration)
Skin Turgor/Mucus Membranes
Peripheral perfusion (CRT raised)
Pulse rate (raised) and volume (low)
BP (low, postural drop)
JVP (raised in fluid overload)
Chest sounds (pulmonary oedema)
Peripheral Oedema
Urine output
Clinical examination must
include (continuation):

general


signs of renovascular disease



Rash, uveitis, joint swelling
audible bruits
impalpable peripheral pulses
abdominal examination

palpable bladder
AKI Outcomes:




Renal function loss – i.e. persistent loss of
renal function lasting > 4 weeks
End Stage Kidney Disease – i.e. GFR <
15ml/min for > 3 months
Other associated complications – e.g. sepsis,
bleeding, respiratory failure etc.
Increased Mortality
Investigations:

biochemistry


haematology



Urea and electrolytes
FBC
urinalysis (± microscopy)
microbiology

urine culture (if infection is suspected)

blood culture (if infection is suspected)
Specific renal investigations
(dependent upon the clinical presentation)


renal immunology
urinary biochemistry





electrolytes
osmolality
ECG, Chest x-ray
abdominal x-ray
renal tract ultrasound (within 24hrs if obstruction
suspected or esoteric cause suspected requiring a
kidney biopsy)

kidney biopsy
Principles of Treatment:

Check Medication! Stop all nephrotoxic
(Concurrent medications that interfere with GFR autoregulation
or renal blood supply)






ACE inhibitors
Angiotensin Receptor Blockers (ARBs)
Ciclosporin (ulcerative colitis)
NSAIDs
Tacrolimus (immunomodulator)
Check that the dosages of those remaining
/commencing are correct in renal failure
(Enoxaparin, some antibiotics)
Principles of Treatment:





Treat lifethreatening hyperkalaemia first
Correct hypovolaemia/hypoperfusion –
restore pressure
Exclude obstruction ASAP (Imaging)
Treat the underlying cause
Consider Renal replacement therapy if
no response
Case 1
66 y.o. man presents to A&E at 10 am
 PC: increasing SOB for 7/7, coughing up phlegm and
having fever.
 PMH: DM, HTN
O/E: pale, sweaty, BP 85/50, HR 115, Sats 92% on air, RR
25, T 38.3, coarse crackles on the right side of his chest.
 CXR - RLL pneumonia.
 Blood results: Na 130, K 4.5, Urea 14.3, Cr 189

The nurse asks you to reassess the patient at 2 pm as he
hasn't passed urine since admission.
Current obs: HR 95, BP 95/55, Sats 96%, RR 22, T 37.5
What would be your actions?
Medical management:
Pt’s cardex:
Stat: paracetamol 1g IV
Oxigen 6 L
Regular:
Enoxaparin 40 mg, metformin, aspirin, ramipril, atenolol

and simvastatin
Nebs with Soduim Chloride 0.9%
Abx: Co-amoxiclave 1.2 g and Clarithromycin 500mg
PRN: paracetamol 1g PO/IV, not more than QDS
Salbutamol 2.5-5 ml nebs
Initial management:





Assess the patient (A-E) including volume
status, check the catheter if in place (might
be blocked or misplaced)
CHECK CURRENT MEDICATIONS!
Check patient’s base line U&E or previous
if available
Investigations: Urine dip (if not done already)
Treatment: fluid resuscitation, call for senior
help
Fluid balance
(adults, resting state, mL per day)
Totaling: in/out ~2500 ml/day
Maintenance fluids:
WEIGHT
For the first 10 Kg
For the next 10-20 Kg
For each Kg above 20
RATE
100 mL/kg/24hrs
Add 50 mL/kg/24hrs
Add 20 mL/kg/24hrs
or
or
or
4 mL/kg/hr
+2 mL/kg/hr
+1 mL/kg/hr
So, the maintenance fluid requirements for a 70-kg adult is
1000 + 500 + 1200 = 2700
(mL/24hrs)
Or 40 + 20 + 50 = 110 (mL/hr)
Fluid requirements in illness:

Missing maintenance is estimated by
multiplying the normal maintenance volume by the length
of the fasting period:
 Case: 89 yo male, was found lying on the floor in his flat
for approximately 6 hours. He is know to have advanced
dementia.
Fluid requirements for 24 hours:
Maintenance fluid 3L
Missing maintenance 600 ml
Total: 3600 ml
Fluid requirements in illness:

Increased insensible losses due to
hyperventilation, fever and sweating - an
extra 500 ml/day is required for every degree Celcius above 37, ~20
ml/hr);

Case: 60 yo. Female, admitted due to CAP, her
temperature is 38.5
Fluid requirements for 24 hours:
Maintenance fluid 3L
Insensible loses 720 ml
Total: 3720 ml
Fluid requirements in illness
Maintenance requirements for an adult
Na - 50-100 mmol/day
K - 40-80 mmol/day
In 1.5-2.5 Iitres of water by the oral, enteral or
parenteral route (or a combination of routes).
Additional amounts should only be given to
correct deficit or continuing losses
Contents of common crystalloids in
mmol/L
Na
K
Ca
Cl
HCO3 Osm
Plasma
140
4
2.3
100
26
285-295
Na Cl 0.9%
Dextrose 5%
Dex.Saline
Hartmann’s
154
0
30
131
0
0
0
5
0
0
0
0
308
252
255
278
5.0
4.0
4.0
6.5
Ringer’s
147
4
0
154
0
0
0
0
2
111
Lactate 29
2.2
156
Lactate 28
0
0
0
0
0
302
6.9
150
1000
300
2000
8.0
8.0
Na Bicarb 1.2% 150
Na Bicarb 8.4% 1000
0
0
pH
7.4
Fluid requirements in illness
Excessive losses from gastric aspiration/vomiting
crystalloid solution with K supplement.
↓Cl - 0.9% NaCl + K (sufficient amount) and care not
to produce sodium overload.
↓Na (excessive diuretic exposure) - Hartmann's
Diarrhoea, ileostomy, small bowel fistula, ileus,
obstruction - volume for volume with Hartmann's
.
What is Hyperkalaemia?
Level of potassium above 5.5 mmol/l in venous
blood
ECG changes (peaked T waves and
broadening of QRS complex) are important
but may NOT be seen even if potassium
level is life threatening
May cause sudden death or progressive
bradycardia and death
ECG Changes:
Causes of Hyperkalaemia:

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AKI/Renal failure
Sepsis with acute kidney injury
Drugs (spironolactone, ACE
inhibitors, amiloride and OTHERS)
Treatment:
K+ >6.0
mmol/l
Calcium resonium 15G qds PO in water,
recheck K+ after 2 hours
K+ >6.5
mmol/l
Above plus: Refer to a nephrologist,
Dextrose-insulin (10U actrapid insulin in 50ml 50%
dextrose, intravenously, over 5 minutes, check BM every
30min for 2 hours
K+ >7.0
mmol/l
Above plus: URGENT REFERRAL
Neb Salbutamol 5mg and repeat in 2 hours
IV Sodium Bicarbonate 500ml 1.26% over 30 mins OR
If central line in situ:
IV Sodium Bicarbonate 50ml 8.4% over 5 mins
(not in pulmonary oedema)
IV Calcium Gluconate 10ml 10%
Recheck K+ and BM in 2 and 4 hours
Acute Renal Failure →
Emergency Haemodialysis:

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K+ > 7mmol/L, resistant to medical therapy
Pulmonary oedema refractory to medical
therapy
Metabolic pH < 7.2 or base excess < -10
Other possible indications include:
Uraemic pericarditis
Uraemic encephalopathy
Renal Replacement Therapy
Dialysis:
 No clear proven advantage
for either in treatment of
renal failure
 Theoretical advantage of
clearance of middle
molecules
Haemofiltration:
 No need to transfer patient
to renal unit
 Can be continuous
 Improved haemodynamic
stability
 Permits vasopressers and
other drug therapies
including TPN
 Reduced risk of
disequilibrium syndrome
When to call nephrology?
Any known dialysis patient admitted
 Any known renal transplant patient
admitted

Any case of AKI where cause is not clear
 Worsening AKI
 Emergency dialysis indications
 Suspect glomerulonephritis

Summary:

worry if
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Patient has not passed urine or very little
U&E creatinine is going up, check dynamics
Patient is dehydrated plus cardiovascular
compromised (past MI, CCF)
remember


Normal creatinine does not mean patient is not
developing AKI
Call early for senior or specialist help
Thank you!
Any questions?