Exam 3 - Kidney

Question 1

What are the responsibilities of the kidneys?

Answer 1

A = Acid/base
W = Water
E = Electrolytes
T = Toxin Removal
B = Blood Pressure Regulation
E = Erythropoietin
D = Vitamin D Activation

Question 2

What does the kidneys excrete?

Answer 2

Hydrogen Ions, Urea, and Creatinine

Question 3

What is the significance of hydrogen ions in kidney function?

Answer 3

Hydrogen is acidic; if kidneys are functioning, you will see metabolic acidosis.

Question 4

What is urea?

Answer 4

A waste product of ammonia (detoxed in liver) filtered down to kidneys.

BUN – Blood urea Nitrogen (How much concentration of urea do we have in blood?)

Question 5

What is creatinine?

Answer 5

A byproduct of muscle breakdown.

Question 6

What are the normal lab values for BUN?

Answer 6

7 – 20 mg/dl

Question 7

What are the normal lab values for creatinine in men?

Answer 7

0.7 to 1.3 mg/dL (61.9 to 114.9 μmol/L)

Question 8

What are the normal lab values for creatinine in women?

Answer 8

0.6 to 1.1 mg/dL (53 to 97.2 μmol/L)

Question 9

What does specific gravity in urine indicate?

Answer 9

Shows concentration; 1.03 = very concentrated.

Question 10

What is the relationship between GFR and creatinine?

Answer 10

GFR is roughly 3 times that of creatinine.

Question 11

What does an increase in both BUN and creatinine indicate?

Answer 11

Kidney problem.

Question 12

What does an increased BUN with normal creatinine suggest?

Answer 12

Most likely dehydration.

Question 13

How does kidney disease impact morbidity and mortality?

Answer 13

It is a predictor of major cardiac events and has a direct relationship between GFR and postoperative morbidity & mortality.

Question 14

What is the risk increase for death and cardiac issues with early stage CKD?

Answer 14

2-5 fold increase.

Question 15

What are the effects of renal disease on length of stay (LOS)?

Answer 15

Increase in length of stay.

Question 16

What defines chronic kidney disease (CKD)?

Answer 16

Decrease GFR < 60 for greater than 3 months, representing at least ½ loss of adult kidney function.

Question 17

How is GFR calculated?

Answer 17

Using the Modified Diet in Renal Disease equation or Cockcroft - Gault equation.

Question 18

How is GFR reported?

Answer 18

On a basic metabolic profile.

Question 19

What are the challenges in diagnosing the preoperative setting under kidney standpoints?

Answer 19

It may be difficult due to the 3-month requirement to diagnose. Take a good history including hypertension, diabetes, obesity, heart failure, cirrhosis, and ethnicity (African American, American Indian, Hispanic, Pacific Islander).

Question 20

What are the blood pressure targets for patients with hypertension and CKD under 60 years?

Answer 20

Blood pressure should be less than 140/90.

Question 21

What are the blood pressure targets for patients with hypertension and CKD over 60 years?

Answer 21

Blood pressure should be less than 150/90.

Question 22

What are the first-line therapies for hypertension in CKD?

Answer 22

ACE inhibitors (ACEI) and Angiotensin II receptor blockers (ARB) are first-line therapies due to their renal protective effects.

Question 23

What should be considered regarding blood pressure control during surgery?

Answer 23

It is important to weigh the risks for blood pressure control with possible hypotension during surgery.

Question 24

What are common causes of anemia in CKD?

Answer 24

Iron deficiency and erythropoietin deficiency or hyporesponsiveness. Transfusion may be required.

Question 25

What is the goal hemoglobin level for patients with CKD?

Answer 25

The goal hemoglobin level is 11-12 g/dl, but should not exceed 13 g/dl.

Question 26

What medications should be avoided in CKD?

Answer 26

Non-steroidals, IV contrast dye, metformin, lithium, digoxin. Avoid ACEI and ARB 24-48 hours preoperatively.

Question 27

What is the incidence of acute kidney injury (AKI) in hospitalized patients?

Answer 27

AKI occurs in 2-18% of all hospitalized patients and 20-57% of all ICU patients.

Question 28

What is the leading cause of AKI in hospitalized patients?

Answer 28

Surgery is the leading cause of AKI in hospitalized patients.

Question 29

What leads to tubular injuries in AKI?

Answer 29

Hypoperfusion and inflammation lead to tubular injuries.

Question 30

What is 'renal angina'?

Answer 30

'Renal angina' usually refers to a hypoperfusion state.

Question 31

What lab ratios indicate intra-renal AKI severity?

Answer 31

A 10 to 1 ratio of BUN to creatinine indicates intra-renal AKI.

Question 33

Preoperative assessment and optimization steps for patients at increased risk of CKD:

Answer 33

Measure blood pressure and compare with home readings if available, perform electrocardiogram, assess functional capacity using the Duke activity status index, check for volume overload (e.g., pedal edema, pulmonary rales), evaluate serum creatinine/eGFR, check serum electrolytes, assess hemoglobin level, review urinary albumin–creatinine ratio from the past year, check Hemoglobin A1c in diabetic patients, encourage smoking cessation, promote routine exercise, and optimize nutritional status with a healthy BMI (20–25)

Question 34

Definition and staging criteria of AKI-RIFLE

Answer 34

Risk: Creatinine increased 1.5× or GFR decreased ≥25%, UOP <0.5 mL/kg/hr for ≥6 hrs Injury: Creatinine increased 2× or GFR decreased ≥50%, UOP <0.5 for ≥12 hrs Failure: Creatinine increased 3× or GFR decreased ≥75%, or Cr ≥4.0 mg/dL with acute rise ≥0.5 mg/dL, UOP <0.5 for ≥24 hrs or anuria for ≥12 hrs Loss: Persistent ARF, complete loss for >4 weeks ESRD: Requires dialysis, permanent renal replacement therapy

Question 35

Definition and staging criteria of AKI-AKIN

Answer 35

Stage 1: Cr increased 1.5× or >0.3 mg/dL, UOP <0.5 for ≥6 hrs Stage 2: Cr increased 2×, UOP <0.5 for ≥12 hrs Stage 3: Cr increased 3× or ≥4.0 mg/dL (acute rise ≥0.5 mg/dL), UOP <0.3 for ≥24 hrs or anuria for ≥12 hrs

Question 37

What is the treatment of choice for End-Stage Renal Disease (ESRD)?

Answer 37

Renal transplant is the treatment of choice for ESRD.

Question 38

What are the organ wait times for renal transplants?

Answer 38

Organ wait times can exceed 4 years.

Question 39

What GFR level indicates the need for a renal transplant?

Answer 39

A GFR of less than 20% indicates the need for a renal transplant.

Question 40

What laboratory tests are required for pretransplant testing?

Answer 40

CBC, platelet count, electrolytes, PTH, amylase, lipase, liver function studies, albumin, prothrombin time, INR, lipid profile, HGA1c, viral serology (HIV, HBV, HCV, EBV, CMV), tissue typing & panel reactive antibody, blood typing.

Question 41

What cardiac tests are indicated for pretransplant testing?

Answer 41

ECG, stress testing (with imaging), and echocardiography as indicated by cardiovascular risk.

Question 42

What pulmonary tests are part of pretransplant testing?

Answer 42

Chest X-ray (CXR) and pulmonary function tests (PFTs).

Question 43

What age-appropriate cancer screenings are required before renal transplant?

Answer 43

PSA, mammography, colonoscopy, and PAP smear.

Question 44

What psychosocial factors are assessed in pretransplant testing?

Answer 44

Social and financial supports, ability to adhere, substance abuse or psychiatric history, understanding of transplant risks and benefits.

Question 45

What are some contraindications for renal transplant?

Answer 45

Active acute infection or malignancy, uncontrolled systemic disease, uncontrolled psychiatric disorder or substance abuse, evidence of treatment nonadherence, limited life expectancy due to advanced lung disease or heart failure, and lack of adequate social and financial support.

Question 47

What is the reevaluation interval for low-risk patients?

Answer 47

Every 3 years ## Footnote Low-risk patients include those aged 18-45 years, ESRD with no other major comorbidities, and no psychiatric disorders.

Question 48

What is the reevaluation interval for intermediate-risk patients?

Answer 48

Every 2 years ## Footnote Intermediate-risk patients include those aged 46-59 years with various risk factors such as previous failed transplantation, dialysis for > 2 years, and more.

Question 49

What is the reevaluation interval for high-risk patients?

Answer 49

Every year ## Footnote High-risk patients include those aged ≥ 60 years or with multiple cardiac risk factors, symptomatic cardiovascular disease, and other serious conditions.

Question 50

What is Contrast Induced Acute Kidney Injury (CI-AKI)?

Answer 50

Dye is used to better visualize structures under x-ray.

Question 51

What are the recommendations to prevent CI-AKI?

Answer 51

Obtain baseline Cr level & eGFR, limit CM volume, use preheated iso-osmolar CM, avoid high-osmolar CM, avoid repeated doses, avoid dehydration, and administer isotonic saline hydration. ## Footnote Isotonic saline hydration includes 0.9% NaCl with NaHCO3.

Question 52

What is the hydration protocol for inpatients to prevent CI-AKI?

Answer 52

0.9% NaCl at 1.5 mL/kg/hr for 12 hours before and after the procedure; NaHCO3 infusion at 3 mL/kg/hr for over 6 hours.

Question 53

What is the hydration protocol for outpatients to prevent CI-AKI?

Answer 53

0.9% NaCl plus NaHCO3 at 3 mL/kg/hr over a minimum of 1 hour, preferably over 6 hours.

Question 54

Mitigating risk of CIN based on GFR:

Answer 54

GFR >60 mL/min – Low risk: No prophylaxis or follow-up needed. GFR 45–59 mL/min – Low to moderate risk if no risk factors: No prophylaxis needed unless receiving intra-arterial contrast, then preventative measures recommended. GFR 30–45 mL/min – Moderate to high risk: Stop nephrotoxic meds (especially metformin), give IV hydration (isotonic NaCl or NaHCO₃), consider sodium bicarbonate and/or N-acetylcysteine; follow-up in SCr 48–72 hrs. GFR <30 mL/min – High risk: Avoid contrast if possible, use non-ionic agents, consult nephrology, consider hemodialysis, same prevention as GFR 30–45; follow-up in SCr 24–72 hrs.