1. <Book review>
Acute kidney injury
2010년 1월 8일
내과 3년차 서정우

2. 주치의 선생님
“크레아티닌이 뜨는데요?”
“소변이 안나옵니다…”

3. 공부할 내용은? 1. Acute kidney injury(AKI)?
; definition, physical examination, further evaluation..
2. Indications for dialytic support in AKI
3. Modality of RRT in AKI

4. AKI ? Common clinical problem defined by an abrupt (within
48hrs) increase in serum creatinine resulting from an
injury or insult that causes a functional or structural
change in the kidney.
First proposed in 2004, by Acute Dialysis Quality Initiative.
(ADQI)
Not mean failure of the kidneys, but a dysfunction.

5. RIFLE criteria category GFR and serum Cr. criteria Urine output
Risk
GFR down by > 25%
Cr times baseline
< 0.5mL/kg/hr for 6hours
Injury
GFR down by > 50%
Cr. 2 times baseline
< 0.5mL/kg/hr for 12hours
Failure
GFR down by > 75%
Cr. 3 times baseline
< 0.3mL/kg/hr for 24hrs or anuria for 12hr
Loss
Persistent complete loss of kidney
Function for > 4wks
ESKD
End stage kidney disease (>3mon.)

6. Diagnostic approach 1. Insult  prerenal / Intrinsic / postrenal
Initial Cr. 상승  Postrenal insult 를 DDx. 해야
- abdominal pain or flank pain
- palpable bladder
- malignancy history
- Kidney USG 시행이 선행되어야

7. Diagnostic approach
2. The patient’s history & careful review of the hospital course
- Presence/absence of hypotension
- blood loss
- recent intravenous contrast administration
- crush injury
- new medication ( particularly antibioitics/diuretics )
- recent invasive vascular procedures

8. Diagnostic approach 3. Assessment of the patient’s volume status
* hypovolemia
- Symptom ; thirst, weakness, muscle cramp,
headache, anorexia, nausea/vomiting
- Sign ; orthostatic hypotension, skin turgor 감소
oliguria, sweating 감소, axillar 습도 감소,
점막 건조, JVP 감소
- Lab. ; Hct., protein 증가, BUN/Cr 증가,
urine Na/osm. 감소 등
* Heart failure ..?

9. Prerenal disorders Management 1) Intravascular volume depletion
- attempt intravenous volume expansion through
normal saline, blood products, or other colloids to
( target CVP of 8-12 mmHg )
- discontinue ACE inhibitors, ARBs, COX II inhibitors,
NSAIDs, and potential nephrotoxins
- Treatment of underlying cause of volume depletions
; blood loss, gastrointestinal losses, extensive burns,
extravasation into extravascular compartments
( Peritonitis, intestinal obsturction)

10. Prerenal disorders Management 2) Renal hypoperfusion
- correct underlying cause (sepsis, cardiogenic shock,
abdominal compartment syndrome)
- appropriate use of diuretics in HF exacerbation
- avoidance of vaso-constricting agents (NSAIDs,
contrast dyes) to prevent progression to tubular
injury

11. Intrinsic renal disorders
Most common cause of AKI in the ICU – ATN
Management
- no specific treatment for ATN
- avoiding additional nephrotoxic insults and
adjusting drug doses appropriately for the level of
renal function

12. Postrenal disorders Recent abdominal surgery History of malignancy
Anticholinergic medications
Obstruction (+)
; bladder catheterization
ureteral stenting
nephrostomy tubes

13. Timing of renal replacment therapy initiation in AKI
Goal of RRT
: attain solute clearance and fluid balance while
waiting for kidney function to recover
→ Timely institution of RRT is fundamental to achiving this goal.
Indications for dialytic support in AKI ?

14. Indications for dialytic support in AKI-
- Volume overload refractory to diuretics
- Hyperkalemia refractory to medical therapy
- Meatbolic acidosis refractory to medical therapy
- Uremic syndrome
- Anorexia, nausea, vomiting
- Seizures, confusion
- Serositis
- Neuropathy
- Bleeding
- Need to start total parenteral nutrition (volume/solute issues)
- Overdoses/intoxications
- Refractory hypercalcemia
- Refractory hyperuricemia

16. Renal replacement therapy
Available modalities
-intermittent hemodialysis(IHD)
-continuous renal replacement therapy(CRRT)
-sustained low-efficiency dialysis(SLED)
-peritoneal dialysis(PD)
Choice of modalities
-availability of therapy at the institution
-physician preference
-the patient’s hemodynamic status
-the presence of co-morbid conditions

17. Renal replacement therapy
Sepsis or hepatic failure : continuous therapy
Intracranial pressure is more stable with CRRT than with IHD in patients with hepatic encephalopathy. (small study)
CRRT : same solute clearance and fluid removal
favor hemodynamic unstable patients but, not shown
a difference in time to renal recovery or length of
ICU or hospital stay with IHD.
-Dialysis in intensive care unit patients with acute kidney
injury :continuous therapy is superior
(Claudio Ronco, CJASN 2:2007)

19. 경청해 주셔서 감사합니다.