Avoiding Kidney Injury:
Overview,
Pathophysiology, &
Definitions
Objectives
• Discuss incidence and impact of Acute Kidney Injury & Chronic Kidney Disease in surgical
patients
• Review the pathophysiology related to AKI and CKD
• Identify definitions & stages of kidney disease
• Share registry definitions of kidney injury or failure & review ASPIRE AKI 01 measure
• For other recommendations to avoid AKI, reference additional toolkit components:
– Avoiding Kidney Injury - Recommendations for Adult Surgical Patients
– Avoiding Kidney Injury - Pediatrics
– Avoiding Kidney Injury - Obstetrics
– Avoiding Kidney Injury - Cardiac Surgery
AKI Incidence
9%
Non-cardiac
inpatient surgery
patients develop
AKI
4
25%
Of trauma patients
develop AKI
5
52-56%
Of patients
admitted to ICU
after surgery
6
13.3
million
Patients per year
develop AKI
worldwide
1
1.7 million
Deaths per year
worldwide
attributed to AKI
1
7-13%
Surgical patients
suffer with AKI
2
70%
mortality rate for
patients with
sepsis and AKI
3
Impact of AKI
• AKI can be an early indicator of multi-organ dysfunction with significant effects on
mortality
7-9
• Effects of AKI can last years and lead to development of chronic kidney disease or
ESRD, even for patients whose creatinine improves at the time of discharge
2,5,10-11
Cost of care for
surgical
patients:
$26,700
38
Cost of care for
surgical patients
with AKI:
$42,600
38
AKI Impact
• In industrialized countries, acute kidney injury (all cause)...
– Claims 300,000 lives annually
– Contributes to 300,000 new CKD cases annually
– Results in 170,000 end stage kidney disease diagnoses
12
• In the United States alone, AKI costs an estimated $10 billion annually
13
• Compared to postoperative patients without AKI, patients with AKI are associated with:
LOS increased
from 8.6 to
15.8 days
37
Mortality
increased from
8% to 19%
37
30 day
readmission
13% vs 21%
37
1yr ESRD .94%
vs .05%
37
CKD Incidence
➔ Estimated global prevalence
11-13%
14
➔ Over 1 in 7 adults in the
United States have CKD
15
➔ 90% do not know that they
have CKD
15
➔ 9th Leading cause of death in
the US
16
CKD Impact
- 14.5% of Medicare patients age 65 and older have CKD
17
- Medicare spent $120 billion on ESRD and CKD in 2019 (⅓ of all Medicare Fee for
Service spending)
17
No CKD
Non-ESRD CKD
Yearly Medicare
spending per
beneficiary with non-
ESRD CKD is over
$23,500, nearly double
than for average
Medicare beneficiary
17
Pathophysiology of
Kidney Disease
Kidney Disease Overview - Conditions that affect structure and function of the
kidneys
18
- Acute Kidney Injury
- Acute Kidney Disease
- Chronic Kidney Disease
- End Stage Renal Disease
Conditions can be categorized by length of time
Acute Kidney Injury
An abrupt decline in
kidney function occurring
over a period of 7 days or
less
19
Acute Kidney Disease
When acute kidney injury
persists > 7 days
20
Chronic Kidney Disease
Abnormalities in kidney
structure or function that
persist beyond 90 days
19
Acute Kidney Injury: General Definition
Several AKI Classification Systems Exist:
18
a. RIFLE - Risk, Injury, Failure, Loss, End Stage - 2004
b. AKIN - Acute Kidney Injury Network - 2007
c. KDIGO - Kidney Disease Improving Global
Outcomes- 2012
*See slides 6-12 for classification system criteria & slide 21 for biomarker explanation.
Acute Kidney Injury
An abrupt decline in kidney
function occurring over a
period of 7 days or less
19
AKI Pathophysiology
• Historically, cause of
disease was divided into
prerenal, renal (intrinsic),
and post renal
18
• This approach does not
account for multifactorial
causes
18
Image Source: Makris 2016
Etiology: Prerenal
• Prerenal AKI is the result of
hypovolemia or low cardiac
output
18
• No damage to renal parenchyma
7
• Can progress to Intrinsic AKI if
hypovolemia insult continues and
damage occurs
22
*Adapted from Makris 2016
25% of cardiac output
goes to the kidneys
7
Renal hypoperfusion leads to
decreased GFR as an adaptive
response. Water, sodium, and
urea retained to conserve
volume
21
Etiology: Prerenal Possible Causes
7
Impaired Cardiac
Function: Congestive heart
failure, acute myocardial
infarction, massive pulmonary
embolism
Increased Vascular
resistance: Anesthesia,
surgery, hepatorenal syndrome,
NSAID medications, drugs that
cause renal vasoconstriction
Systemic Vasodilation:
Anti-hypertensive medications,
gram negative bacteremia,
cirrhosis, anaphylaxis
Hypovolemia: Hemorrhage,
volume depletion, renal fluid loss
(over-diuresis), third space
(burns, peritonitis, muscle
trauma)
Etiology: Renal (Intrinsic)
• Results of injury to kidney structures: tubules,
glomeruli, the interstitium, and intra-renal blood
vessels
7
• Acute Tubular Necrosis (ATN) - AKI from damage to
tubules. This is the most common type of Intrinsic
AKI
7
*Adapted from Makris 2016
Etiology: Intrinsic Possible Causes
7
Tubular: Renal ischemia
(shock, complication of surgery,
hemorrhage, trauma, bacteremia,
pancreatitis, pregnancy),
nephrotoxic drugs (antibiotics,
antineoplastic drugs, contrast
media, organic solvents,
anesthetic drugs, heavy metals)
endogenous toxins (myoglobin,
hemoglobin, uric acid)
Glomerular: Acute post
infectious glomerulonephritis,
Lupus nephritis, IgA
glomerulonephritis, infective
endocarditis, Goodpasture
syndrome, Wegener disease
Interstitium: Infectious
(bacterial, viral), medications
(antibiotics, diuretics, NSAIDs,
etc)
Vascular: Large vessels
(bilateral renal artery stenosis,
bilateral renal vein thrombosis),
small vessels (vasculitis,
malignant hypertension,
atherosclerotic or thrombotic
emboli, hemolytic uremic
syndrome, thrombotic
thrombocytopenic purpura)
Etiology: Postrenal
• Caused by blockage of urinary flow in the urinary tract
18
• Obstruction → ↑ intratubular pressure and ↓GFR
22
• Leads to build up in the kidney
22
• Quick resolution = best chance of kidney recovery
7
Etiology: Post Renal Possible Causes
7
Extrarenal Obstruction:
Prostate hypertrophy, improperly
placed catheter, bladder, prostate
or cervical cancer, retroperitoneal
fibrosis
Intrarenal Obstruction:
Nephrolithiasis, blood clots,
papillary necrosis
AKI Impact on
Organ
Function
*Image Source: Gumbert et al. Anesthesiology 2020
AKI Risk Factors
Categories of AKI Risk Factors
• Patient-related, such as:
– Diabetes
– Hypertension
– Sepsis
• Procedure-related, such as:
– Cardiopulmonary bypass & duration
– Emergency Surgery
– Organ Transplant
• Anesthesia-specific, such as:
– Vasopressor use
– Diuretic use
– Hypotension
Patient Risk Factors
23-25
• Preoperative level of kidney function
• Chronic Vascular Disease
• Arterial Hypertension
• Cardiac Failure/Cardiac Decompensation
• Diabetes (insulin or oral therapy
requirements)
• Acute medical conditions (sepsis, major
surgery, mechanical ventilation,
hemodynamic instability)
• Hypertension
• Peripheral Vascular Disease
• Congestive Heart Failure
• Sepsis
• Ascites
• Cerebrovascular disease
• Mild to Moderate preoperative renal
insufficiency
• Age >65
• COPD
• Chronic Kidney Disease
• BMI ≥ 25 (Overweight) (Ju 2018)
Patient-related risk factors are more strongly associated with mortality
than the type of procedure
23
Procedure Related Risk Factors
10, 23, 25
•
Gastric bypass surgery for morbid
obesity- 8.5% incidence AKI
•
Cardiopulmonary bypass (CPB) &
duration
•
Aortic cross clamping & duration
•
Hemodilution (cardiac surgery)
•
Duration of surgery
•
Intraperitoneal surgery
•
Repair of AAA
•
Organ transplant (non-renal also)
– Liver Transplant
– 33% develop AKI
– 17% require RRT
•
Use of intra-aortic balloon pump
•
Type of cardiac surgical procedure
•
Intra-abdominal hypertension
•
Emergency surgery
•
Bleeding complications
Anesthesia-related Risk Factors
Potentially modifiable AKI risk factors in both cardiac and noncardiac surgery
10, 23, 25
– Hemodilution
– Hemoglobin level
– Intraoperative transfusion
– Hypotension
– Inadequate oxygen delivery
– Use of diuretics
– Selective renal ischemia
– Ischemia reperfusion injury
– Bleeding complications
– Intraoperative Hypertension
– Nephrotoxic agents (eg abx, contrast agents)
Acute Kidney Injury
Classification Systems
AKI Classification Systems: RIFLE
• First attempt at a unifying
definition for AKI (then called
acute renal failure)
26
• Published in 2004, RIFLE
graded AKI Stages and
provided taxonomies for both
severity and recovery
10
• Proposed 1 week timeframe
for AKI Diagnosis
27
Image Source: Ricci, Cruz, & Ronco Kidney International 2008
GFR Criteria Urine output criteria
Risk
Increased creatinine x1.5
or GFR decrease >25%
UO <0.5ml kg
-1
h
-1
x6h
High
Sensitivity
Injury
Increased creatinine x2
or GFR decrease >50%
UO <0.5ml kg
-1
h
-
1
x12h
Failure
Increased creatinine x3
or GFR decrease >75%
or creatinine ≥4mg per
100mL (acute rise of
≥0.5mg per 100ml dl)
UO < 0.3 kg
-1
h
-1
x24h
or anuria x12h
(Oliguria)
High
Specificity
Persistent ARF = complete loss of renal function
>4 weeks
Loss
ESRD
End Stage Renal Disease (>3 months)
Diagnostic criteria:
- 1 week timeframe for AKI diagnosis
- Grades patients based on the worse
category for GFR/UO
AKI Classification Systems: RIFLE
• Previously over thirty different definitions of acute renal failure were in use
26
• Caused shift in terminology: “Acute Renal Failure” → “Acute Kidney Injury”
• Highlighted importance of identifying changes in kidney function earlier to prevent
failure
28
• Validated in multiple studies for its ability to classify patients and was strongly tied to
patient outcomes in the acutely ill
28
AKI Classification Systems: RIFLE
Limitations
• Smaller increases in SCr than those defined in “Risk” (<1.5x) are associated with
poor outcomes
27
• Urine output component unreliable (may be influenced by other factors such as
diuretic use)
27
• When using estimated GFR in place of a true baseline GFR, the formulas that
estimate GFR presume a “steady state” for GFR that is absent in patients with
acutely changing kidney function
27
• Urine output alone used for staging was not found to be an accurate predictor of
AKI; Cr and urine output should be assessed together for accurate staging & as a
predictor of ICU mortality
29
AKI Classification Systems: Acute Kidney Injury Network (AKIN)
27,30
Cr Criteria Urine output criteria
Stage 1 Increased creatinine x1.5 or
≥ 0.3mg/dl
UO <0.5ml/kg/hr x6 hr
Stage 2 Increased creatinine x2 UO <0.5ml/kg/hrx12h
Stage 3 Increased creatinine x3 or
Cr ≥ 4 mg/dl (with acute rise
of ≥0.5mg/dl)
UO < 0.3 ml/kg/hr x24h
or anuria x12h
(Oliguria)
Patients who receive renal replacement therapy (RRT)
are considered to have met the criteria for stage 3
irrespective of the stage that they are in at the time of
commencement of RRT
Diagnostic criteria:
- Serum creatinine measured over 48 hours
- Grades patients on urine output and change in
SCr over 48 hours
- 7 day timeframe for staging AKI
GFR Criteria Urine output criteria
Risk
Increased creatinine x1.5 or
GFR decrease >25%
UO <0.5ml kg
-1
h
-1
x6h High
Sensitivity
Injury
Increased creatinine x2 or
GFR decrease >50%
UO <0.5ml kg
-1
h
-1
x12h
Failure
Increased creatinine x3 or
GFR decrease >75% or
creatinine ≥4mg per 100mL
(acute rise of ≥0.5mg per
100ml dl)
UO < 0.3 kg
-1
h
-1
x24h
or anuria x12h
(Oliguria)
High
Specificity
Persistent ARF = complete loss of renal function >4
weeks
Loss
ESRD
End Stage Renal Disease (>3 months)
Diagnostic criteria:
- 1 week timeframe for AKI diagnosis
- Grades patients based on the worse category
for GFR/UO
RIFLE Criteria
AKIN Criteria
Removed GFR
Introduced 48h
timeframe
New RRT
Staging
AKI Classification Systems: AKIN
• Introduced in 2007 to improve accuracy after RIFLE release
27
• Relies on serum creatinine measured over 48 hours but does not use GFR
• Grades patients on urine output and change in SCr over 48 hours
• Higher diagnostic accuracy than RIFLE
30
AKI Classification Systems: AKIN
Limitations
- 48 hour timeframe for diagnosis of AKI may miss slowly progressing AKI
27
- While diagnosis of AKI is based on a change in SCr over 48 hours, a 1 week
timeframe is used for staging AKI
27
AKI Classification Systems: KDIGO Criteria (2012)
31
Cr Criteria Urine output criteria
1
Increased creatinine
x1.5-1.9 from baseline
or
≥ 0.3 mg/dl
UO <0.5ml/kg/hr for
6-12hr
2
Increased creatinine
x2.0-2.9 from baseline
UO <0.5ml/kg/hr ≥
12h
3
Increased creatinine x3
from baseline OR SCr ≥
4.0mg/dl OR RRT
UO < 0.3 ml/kg/hr for
≥ 24h
or anuria ≥ 12h
Diagnostic criteria for AKI:
- SCr increase ≥0.3mg/dl within 48h OR
- SCr increase ≥1.5 times baseline, which
is known or presumed to have occured
within the last 7 days OR
- Urine volume < 0.5 ml/kg for 6h
Kept SCr increase
of ≥ 0.3 mg/dl
within 48 hours
from AKIN
Used 7 day
timeframe for
1.5X increase in
SCr from RIFLE
SCr criteria
mostly
unchanged from
AKIN
Removed acute
rise criteria. Kept
RRT criteria from
AKIN
UO criteria
unchanged
GFR Criteria Urine output criteria
1 Increased creatinine
x1.5-1.9 from baseline or
≥ 0.3 mg/dl
UO <0.5ml/kg/hr for
6-12hr
2 Increased creatinine
x2.0-2.9 from baseline
UO <0.5ml/kg/hr ≥
12h
3 Increased creatinine x3
from baseline OR SCr ≥
4.0mg/dl OR RRT
UO < 0.3 ml/kg/hr for
≥ 24h
or anuria ≥ 12h
Diagnostic criteria for AKI:
- SCr increase ≥0.3mg/dl within 48h OR
- SCr increase ≥1.5 times baseline, which
is known or presumed to have occured
within the last 7 days OR
- Urine volume < 0.5 ml/kg for 6h
GFR Criteria
Urine output
criteria
Risk Increased creatinine
x1.5 or GFR decrease
>25%
UO <0.5ml kg
-1
h
-
1
x6h
Injury Increased creatinine
x2 or GFR decrease
>50%
UO <0.5ml kg
-1
h
-
1
x12h
Failure Increased creatinine
x3 or GFR decrease
>75% or creatinine
≥4mg per 100mL
(acute rise of ≥0.5mg
per 100ml dl)
UO < 0.3 kg
-1
h
-
1
x24h
or anuria x12h
(Oliguria)
Persistent ARF = complete loss of renal
function >4 weeks
Loss
ESRD End Stage Renal Disease (>3 months)
Diagnostic criteria:
- 7 day timeframe for AKI diagnosis
- Grades patients based on the worse
category for GFR/UO
Cr Criteria
Urine output
criteria
1 Increased creatinine
x1.5 or ≥ 0.3mg/dl
UO <0.5ml/kg/hr x6
hr
2 Increased creatinine x2 UO
<0.5ml/kg/hrx12h
3 Increased creatinine x3
or Cr ≥ 4 mg/dl (with
acute rise of ≥0.5mg/dl)
UO < 0.3 ml/kg/hr
x24h
or anuria x12h
(Oliguria)
Patients who receive renal replacement therapy
(RRT) are considered to have met the criteria
for stage 3 irrespective of the stage that they
are in at the time of commencement of RRT
Diagnostic criteria:
- Serum creatinine measured over 48
hours
- Grades patients on urine output and
change in SCr over 48 hours
- 7 day timeframe for staging AKI
RIFLE - 2004
AKIN - 2007
KDIGO - 2012
31
Differences between RIFLE, AKIN, & KDIGO Staging/Criterion
• RIFLE, AKIN, & KDIGO have been shown to have similar predictive ability for in-hospital
mortality
30
• In one 2017 study, RIFLE and KDIGO diagnosed more patients with AKI than AKIN
30
• AKIN may under diagnose AKI as compared to RIFLE and KDIGO
31
Kidney Disease: Progression from AKI to CKD and/or Renal Failure
Patients who develop AKI
during surgery demonstrate
an 8-fold increased risk of
progression to CKD
23
8x
Of CKD patients who
experience an episode of
AKI after cardiac surgery will
progress to a worse CKD
class
32
34-53%
• KDIGO Clinical Practice Guideline for AKI (2012) recommends patients follow-up
within 3 months after experiencing AKI after surgery to assess for progression to CKD
33
• Patients who recover from AKI may not return to baseline kidney function -
irreversible decline in kidney function is more likely for patients ≥ 65 years old
34
Chronic Kidney Disease
Chronic Kidney Disease Classification
Chronic Kidney Disease
Abnormalities in kidney
structure or function that
persist beyond 90 days
● CKD Classification based on:
a. Presence or absence of systemic disease
b. Location of pathology within kidney
Chronic Kidney Disease Definition
• Abnormalities in kidney structure or function that persist beyond 90 days
19
• Can result from a variety of causes of kidney damage
• Higher risk of end stage renal disease (ESRD)
33
KDIGO Criteria 2012
Criteria for CKD (either of the following present for >3 months)
Markers of kidney
damage (one or more)
Albuminuria (AER≥30mg/24h; ACR≥30mg/g [≥3mg/mmol])
Urine sediment abnormalities
Electrolyte and other abnormalities due to tubular disorders
Abnormalities detected by histology
Structural abnormalities detected by imaging
History of kidney transplantation
Decreased GFR
GFR<60ml/min/1.73m
2
(GFR categories G3a-G5)
CKD Staging
Figure Source: 2012 KDIGO Clinical Practice Guidelines for Chronic Kidney Disease
GFR Categories in CKD
Category
GFR (ml/min/1.73m
2
)
G1
>90
G2
60
-89
G3a
45
-59
G3b
30
-44
G4
15
-29
G5
<15
*Relative to young adult level
In the absence of evidence of kidney damage, neither GFR category G1 or G2 fulfill the criteria for
CKD
Albuminuria categories in CKD
Category
Albumin excretion
rate
Albumin to creatinine ratio (Approximate
equivalent)
Terms
A1
<30 mg/24h
<3 mg/mmol
<30 mg/g
Normal to mildly
increased
A2
30
-300 mg/24h
3-
30 mg/mmol
30
-300 mg/g
Moderately
increased*
A3
>300 mg/24h
>30 mg/mmol
>300 mg/g
Severely increased**
*Relative to young adult level
**Including nephrotic syndrome (albumin excretion usually >2200mg/34 hours [ACR>220mg/g; >220mg/mmol])
CKD Pathophysiology
Examples of systemic diseases affecting the
kidney
Examples of primary kidney disease
(absence of systemic disease affecting
the kidney)
Glomerular diseases Diabetes, systemic autoimmune diseases,
systemic infections, drugs, neoplasia (including
amyloidosis)
Diffuse, focal or crescentic proliferative
GN; focal and segmental
glomerulosclerosis, membranous
nephropathy, minimal change disease
Tubulointerstitial
diseases
Systemic infections, autoimmune, sarcoidosis,
drugs, urate, environmental toxins (lead,
aristolochic acid), neoplasia (myeloma)
Urinary-tract infections, stones,
obstruction
Vascular diseases Atherosclerosis, hypertension, ischemia,
cholesterol emboli, systemic vasculitis, thrombotic
microangiopathy, systemic sclerosis
ANCA-associated renal limited vasculitis,
fibromuscular dysplasia
Cystic and congenital
diseases
Polycystic kidney disease, Alport syndrome, Fabry
disease
Renal dysplasia, medullary cystic disease,
pondocytopathies
Figure Source: 2012 KDIGO Clinical Practice Guidelines for Chronic Kidney Disease
Risk of Progression of AKI to CKD
• Risk of progression to advanced
chronic kidney disease has been
developed by an externally
validated prediction model
among hospital inpatients
experiencing AKI, with all data
available at the time of detection
of acute kidney injury
39
.
Emerging Research:
Biomarkers
Biomarkers
Current research activities aim to identify new biomarkers, which are released before sCR
increases and/or urinary output declines
23
- The production and release of possible biomarkers of early tubular stress is triggered
by surgical trauma, cardiopulmonary bypass, or other noxious events
- Several issues have to be addressed before these biomarkers can be introduced into
daily clinical routine
- Lack of sensitivity that is related to the etiological heterogeneity of AKI, and the lack of specificity
that seems related to extrarenal causes for fluctuations in serum or urine concentration of the
biomarkers
- NGAL- neutrophil-gelatinase-associated lipcalin → considered the troponin of the kidneys, can only
predict AKI in patients with prior normal kidney function
- Tissues inhibitor of metalloproteinases-2 (TIMP-2)
- Insulin-like growth factor binding protein (IGFBP7)
Subclinical AKI
- Recently defined with the introduction of biomarkers
- Increased biomarker presence without fulfilling KDIGO criteria is considered subclinical
35
- NGAL - neutrophil gelatinase-associated lipocalin
- Excreted when there is tubular damage
35
- Proposed cut off for tubular damage 100-150 ng/mL
- Functional AKI meets KDIGO criteria but does not have biomarker increase
- Subclinical AKI are associated with adverse outcomes despite not meeting KDIGO AKI
criteria
36
KDIGO
Criteria
Biomarker
Increase
Functional AKI YES
❌
Subclinical AKI
❌
YES
Registry Definitions:
Kidney Disease
American College of Surgeons (ACS) - NSQIP
Progressive Renal Insufficiency
A rise in creatinine of >2 mg/dl from preoperative value, but with no requirement for
preoperative (within the 2 week timeframe prior to surgery) or postoperative dialysis
Acute Renal Failure Requiring Dialysis
In a patient who did not require dialysis preoperatively (within the 2 week timeframe prior
to surgery), worsening of renal dysfunction postoperatively requiring dialysis (hemodialysis,
peritoneal dialysis, hemofiltration, hemodiafiltration, or ultrafiltration)
Source: ACS NSQIP Variable Definitions
American College of Surgeons (ACS) - Trauma
Acute Kidney Injury- Stage 3*
1. 3 times baseline (SCr) or
2. Increase in SCr to ≥ 4.0 mg/dl (≥ 353.6 µmol/l) or
3. Initiation of renal replacement therapy
*KDIGO Criterion Used
For patients < 18 years:
1. Decrease in eGFR to <35 ml/min per 1.73 m² or
2. Urine output <0.3 ml/kg/h for > 24 hours or
3. Anuria for > 12 hours
Source: NTDS 2020 Data Dictionary
Michigan Trauma Quality Improvement Program (MTQIP)
Acute Renal Insufficiency
1) Rise in creatinine of >2 mg/dl from baseline value, but with no requirement for
dialysis. Assume a baseline value of 1.0 mg/dl in the absence of additional information regarding the patient’s pre-injury
renal function.
Acute Kidney Injury*
1) Increase creatinine x3 or GFR decrease > 75% or
2) Urine output criteria: UO < 0.3ml/kg/hr x 24 hours or
3) Anuria x 12 hours or
4) Requirement of renal replacement therapy
*RIFLE criterion used
Source: Michigan Trauma Quality Improvement Program Data Dictionary
Society of Thoracic Surgeons- Cardiac
Post-op Renal Failure Definition:
1. Increase in serum creatinine level 3.0 x greater than baseline, or serum creatinine level ≥4
mg/dL (acute rise must be at least 0.5 mg/dl) or
2. A new requirement for dialysis postoperatively
*KDIGO Stage 3 Criterion Used
Post-Op-Renal-Dialysis: New requirement for dialysis postoperatively, which may include
hemodialysis, peritoneal dialysis
Post-Op-Dialysis Required After Discharge
Post-Op-Dialysis Duration
Source: STS Adult Cardiac Surgery Database Data Specifications
Registry Definitions: STS- Thoracic
Renal Failure - KDIGO Stage 3 Criteria
1. Increase in serum creatinine level 3.0 x greater than baseline, or serum creatinine level
>=4 mg/dL. Acute rise must be at least 0.5 mg/dl OR
2. A new requirement for dialysis postoperatively
Source: STS General Thoracic Surgery Database Data Specifications
MPOG Measure Definition: AKI 01
• ASPIRE Definition of AKI: Baseline creatinine increased
more than 1.5 times within 7 postoperative days OR the
baseline creatinine level increased by ≥ 0.3 mg/dL
within 48 hours after anesthesia end.
• Baseline serum creatinine is defined as the most recent
serum creatinine resulted in the last 60 days
preoperatively.
• KDIGO Criterion used
Source: MPOG Measures-Acute Kidney Injury
Summary
1. Several definitions of AKI exist but KDIGO is most widely accepted
1. Adverse effects of AKI can last years, even for patients whose creatinine improves at the time of
discharge
5,10-11
1. Patient-related risk factors are more strongly associated with mortality than the type of procedure
23
1. Surgical registries have begun to collect data regarding kidney injury, though definitions vary, these
outcomes can be helpful for both quality improvement and research purposes.
1. For recommendations to avoid AKI, reference additional toolkit components:
– Avoiding Kidney Injury - Recommendations for Adult Surgical Patients
– Avoiding Kidney Injury - Pediatrics
– Avoiding Kidney Injury - Obstetrics
– Avoiding Kidney Injury - Cardiac Surgery
References
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G: International Society of Nephrology’s 0by25 initiative for acute kidney injury (zero preventable deaths by 2025): a human rights
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Kidney Injury after Noncardiac Surgery Is Associated with Long-term Renal Dysfunction: A Retrospective Cohort Study.
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