Abeer elnakera

RC (UK)

Presented By Abeer elnakera

Lecturer of anesthesiaFaculty of Medicine-Zagazig University

Presented By Abeer elnakera

Lecturer of anesthesiaFaculty of Medicine-Zagazig University

RC (UK)

To • Describe RIFLE classification of AKI• Identify the risk factors and causes of

AKI after cardiac surgery• Explain how to

–Predict–Prevent and –Manage acute renal injury after

cardiac surgery

Objectives

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Introduction

Acute kidney injury (AKI) following

cardiac surgery with cardiopulmonary

bypass (CPB) is a serious complication

associated with high morbidity, mortality

and resource utilization.

The incidence of cardiac surgery-

associated AKI (CSA-AKI) in Canada

ranged between 5-30%.

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Acute Renal Injury and Cardiac Surgery

RIFLE classification defines:

Three grades of increasing severity of acute kidney injury which are:

Risk (class R).

injury (class I).

failure (class F).

Two outcome classes:

Loss and end-stage kidney disease.

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Risk: In which there is increased creatinine×1.5 from base

line and there is 25% reduction in GFR and urine output become<0.5 ml/kg/h over 6 h.

Injury: In which there is increased creatinine×2 from base

line and there is 50% reduction in GFR and urine output become<0.5 ml/kg/h over 12 h.

Failure: In which there is increased creatinine×3 from base

line and there is 75% reduction in GFR and urine output become <0.3 ml/kg/h over 24h.

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Loss: Persistent acute renal failure

(ARF). Complete loss of kidney function

for> 4 weeks.

ESRD: End stage kidney disease> 3

months.

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Underlying Causes of Acute Renal Failure

after cardiac surgery:

•Hypoxia, hypotension, hypovolemia

and dehydration.

•The imbalance between pro and anti-

inflammatory cytokines.

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Pre-operative Risk Factors Elderly and female patients.

Obesity (BMI>30kg/ m2).

Low left ventricular ejection fraction,

Congestive heart failure (CHF), presence of

extra cardiac arteriopathy and the need for

intra-aortic balloon pump (IABP)

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Pre-operative Risk Factors (cont.):

Insulin dependent diabetes mellitus

Pre-operative significant reduction in

creatinine clearance.

Pre-operative medications like ACE

inhibitors which has been associated with

a 28% increase in post-operative AKI in

cardiac surgery patients.

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Operative Risk Factors: Non-isolated CABG surgeries and

emergency/salvage operations.

Complex cardiac cases including aortic root

replacement, aortic surgery and simultaneous

CABG with valve replacement carry higher risk of

CRRT than CABG alone.

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Cardiac Risk Scoring System:

High mean EURO score and Parsonnet

score can predict the need for CRRT

after cardiac surgery.

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Operative Risk Factors (cont.):

Prolonged CPB time.

The increase in the length of cross-clamp

time >2hrs.

The increased number of red blood cell

units given.

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Effect of Cardio-Pulmonary Bypass On Renal Function

CPB is associated with the precipitous

fall in MAP upon commencement of CPB

which causes activation of renin-

aldosterone system and sympatho-

adrenal axis, leading to increased sodium

retention and renal vasoconstriction.

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Other vasoactive substances released

during CPB include complement,

kallikrein and bradykinin contribute to

generalized inflammatory response

that increases capillary permeability.

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Hemodilution with CPB:

The incidence of ARI is higher with severe

hemodilution (nHct <21%) and mild

hemodilution (nHct >25%).

Hypothermia during CPB:All studies suggest that hypothermia is not

detrimental to renal function.

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Early Post Operative Risk Factors

Increase Post operative

extubation time.

Prolonged post-operative

ventilation.

Post operative pulmonary

complication.

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Prevention of AKI after Cardiac Surgery

A practical approach to Perioperative renal

protection

Preoperative:

1. Optimize volume status, cardiac output and systemic arterial pressure.

2. Withhold nephrotoxic drugs.3. Maintain adequate glycaemic control in diabetic patients.4. Correct metabolic and electrolyte disturbances.5. Delay surgery until recovery of acute renal dysfunction if

possible.6. Arrange pre-operative dialysis for dialysis-dependent

patients.7. Administer isotonic i.v fluids and N-acetylcysteine for

prevention of radiocontrast-induced nephropathy.

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protection (cont.)

Intraoperative:

1. Optimize volume status, cardiac output and systemic arterial pressure.

2. Avoid nephrotoxic drugs.3. Consider maintaining adequate glycaemic control in all patients.4. Maintain adequate flow and mean systemic arterial pressure

during CPB.5. Limit the duration of CPB.6. Avoid excessive haemodilution.7. Avoid red cell transfusion.8. Consider extra-corporeal leucodepletion.9. Consider haemofiltration during CPB.10. Consider off-pump coronary artery bypass surgery.

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protection (cont.)

Post-operative:

1. Avoid nephrotoxic drugs.2. Maintain adequate glycaemic control in all patients.3. Promptly treat acute cardiac dysfunction.4. Control haemorrhage.5. Manage sepsis aggressively.6. Recognize and treat rhabdomyolysis.7. Recognize and treat intra-abdominal hypertension.8. Provide appropriate organ support for multiple organ

dysfunction syndrome.9. Institute renal replacement therapy for RIFLE grade F

acute renal dysfunction.

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Prediction of AKI after cardiac surgery

• Progression is reversible when early appropriate interventions implemented

diagnostic biomarkers early AKI detection.

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Diagnosis of AKI after Cardiac Surgery

Characteristics of an Ideal Biomarker:

Should be non invasive (blood or urine

sample), easily measured, inexpensive

and produce rapid results.

Highly specific.

Highly sensitive.

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Diagnosis of AKI after Cardiac Surgery

Some of the Biomarkers Used for Diagnosis of AKI:

• Interleukin-18

• Neutrophil-Gelatinase-Associated Lipocalin (NGAL)

• Kidney Injury Molecule-1 (KIM-1)

• Tubular Enzymes

• Cystatin C

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Treatment of AKI

Indications for RRT:The usual renal indication for RRT: Fluid overload unresponsive to diuretic treatment. Hyperkalaemia (>6.5 mmol/L or rapidly rising

level). Azotaemia (urea>36 mmol/L). Sever acidaemia (PH<7.1). Oliguria (urine output<200ml in 12 hours) or

anuria (urine output<50ml in 12 hours). Uraemia complication like bleeding, pericarditis or

encephalopathy.

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Treatment of AKI

Indications for RRT (cont.):Non renal indication for RRT: Removal of endogenous toxins as in severe lactic acidosis. Patients requiring a large amount of fluid, parenteral nutrient

or blood product but at risk of developing pulmonary oedema or acute respiratory distress syndrome (ARDS).

Heart failure. Hyperthermia or hypothermia (core temperature>39.5c

or<30c). Severe dysnatraemia (Na>160mmol/L or<115mmol/L). Sepsis and other inflammatory syndromes as ARDS to remove

the inflammatory mediators by hemofiltration.

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Treatment of AKI

Continuous renal replacement therapy

(CRRT) is often the preferred choice over

intermittent renal replacement therapy

(IRRT) and peritoneal dialysis in the ICU.

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Treatment of AKI

CVVH set

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Treatment of AKI

CVVHD set

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Treatment of AKI

CVVHDF set

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Treatment of AKI

CAVHD set

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The pathogenesis of kidney injury during CPB is complex and involves hemodynamic and inflammatory mechanisms

Intravascular volume expansion, maintenance of renal blood flow and renal perfusion pressure, avoidance of nephrotoxic agents, strict glycemic control and appropriate CPB management are highly efficient measures for renal protection

Early prediction and establishment of CRRT are beneficial

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Early prediction

Usage of the off-pump technique when

possible.

Perioperative renoprotective measures

Early establishment of CRRT when indicated

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Abeer elnakera

Health & Medicine