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

주치의 선생님 “크레아티닌이 뜨는데요?” “소변이 안나옵니다…”

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

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.

RIFLE criteria category GFR and serum Cr. criteria Urine output Risk GFR down by > 25% Cr. 1.5 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.)

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

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

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 ..?

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)

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

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

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

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 ?

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

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

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)

경청해 주셔서 감사합니다.