334 Acute Kidney Injury Flashcards
Common diagnostic features of AKI
Increase in BUN and/or increase in serum crea, reduction in urine volume
ICU mortality rates in AKI
May exceed 50%
Causes of AKI
Prerenal Azotemia
Intrinsic renal Parenchymal disease
Post renal Obstruction
Most comon form of AKI
Inadequate renal plasma flow and intraglomerular hydrostatic pressure
Prerenal Azotemia
Common clinical conditions in Prerenal azotemia
Hypovolemia
Dec cardiac output
Medications: NSAIDs, ARBs, ACEi
Prolonged periods of prerenal azotemia may lead to ischemic injury termed as
Acute TUbular NEcrosis (ATN)
Renal blood flow accounts for _ % of cardiac output
20%
This maintains GFR despite decreased renal blood flow by renal efferent vasoconstriction
Angiotensin II
This leads to dilataion in the setting of low perfusion pressure therefor maintaining GFR
Myogenic Reflex, prostaglandins, kinins, NO
Renal autoregulation usually fails once SBP falls below __ mm Hg
80 mmHg
These limits renal afferent vasodilation:
Long standing hpn, hyalinosis, myointimal hyperplasia
NSAIDs
These limits renal efferent vasodilation
ACE inhibitors, ARBs
Bilateral renal artery stenosis, unilateral renal artery stenosis
This poses a particularly high risk for developing prerenal azotemia
NSAIDs + ACE inhibitors
Type of Hepatorenal syndrome in which AKI without an alternate cause PERSISTS despite volume administration and witholding of diuretics
Type 1 HRS
This type of Hepatorenal syndrome is less severe form - characterized by REFRACTORY ASCITES
Type 2 HRS
Most common causes of intrinsci AKI
Sepsis, ischemia, nephrotoxins
Pathophysiology of sepsis-induced AKI
Tubular injury, inflammation, mitochondrial dysfunction and interstitial edema
Hemodynamic effects of sepsis in AKI
Generalized arterial vasodilation, expression of NO synthase -> decreased GFR
Healthy kidneys recieve _% of cardiac output and account for _% of resting o2 consumption
20% of cardiac output
10% of o2 cosumption
One of the most hypxic regions in the body
Renal medulla - outer medulla
Most common procedures associated with AKI
Cardiac surgery with bypass, vascular procedures with aortic clamping, intraperitoneal procedures
Risk factors for post op AKI
CKD, old age, DM, CHF, Emergency procedures
AKI is a complication of burns affecting 25% of individuals with more than _% of Total body surface area
10%
Intraabdominal pressure of _mmHG lead to renal vein compression and reduced GFR
20 mmHg
Leading cause of AKI
Iodinated contrast agents for CV and CT imaging