Endocrine Functions of the Kidney

1
Endocrine Functions of the Kidney

• Secretion - renin
• Metabolism - insulin
• Target organ - parathormone
• - aldosterone
• - antidiuretic
• hormone (ADH)

2
Renal Function

• Blood flow 20 - 25 of cardiac
• output
• Glomerular filtration rate (GFR)
• 125 ml/min (normal young adult)
• Urine output 1500 ml/24 hr

3
Renal Function Tests

• Blood urea nitrogen
• normal value 10 - 20 mg/dl
• renal dysfunction gt 50 mg/dl
• Plasma creatinine
• normal value 0.7 - 1.5 mg/dl
• Creatinine clearance
• normal value 110 - 150 ml/min

4
Creatinine Clearance

• Cp x Vp Cu x Vu
• mg/dl ml/min mg/dl ml/min

5
Creatinine Clearance

• Measure
• Cp 1mg/dl
• Cu 100 mg/dl
• 24 - hour urine volume 1440 ml
• (Vu 1 ml/min)

6
Creatinine Clearance

• Cp x Vp Cu x Vu
• 1 x CL 100 x 1
• CL 100 ml/min

7
Effects of Anesthetic Drugs on Renal Function

• Decreases in RBF, GFR, urine output
• Nephrotoxicity (Fluoride ion-polyuria)

8
Chronic Renal Failure Etiology

• Chronic glomerulonephritis
• Diabetic nephropathy
• Pyelonephritis

9
Chronic Renal Failure Circulatory Changes

• Anemia (erythropoietin deficiency)
• Coagulopathy
• Platelet dysfunction
• Systemic heparinization
• Hypertension (renin release)
• Vasoconstriction (angiotensin II)
• Sodium retention (aldosterone)

10
Chronic Renal FailureMetabolic Changes

• Metabolic acidosis (phosphate, sulfate retention)
• Hyperkalemia
• Hypermagnesemia
• Hypocalcemia (from phosphate retention)

11
Chronic Renal FailureImmunosuppression

• Decreased phagocyte activity
• Effects of drugs

12
Postoperative ProblemsChronic Renal Failure

• Recurarization
• Hypertension
• Sensitivity to opioids
• Cardiac dysrhythmias

13
Causes of Perioperative OliguriaPrerenal
(Decreased RBF)

• Hypovolemia
• Decreased cardiac output

14
Causes of Perioperative Oliguria Renal (Acute
Tubular Necrosis)

• Renal ischemia
• Nephrotoxic drugs
• Myoglobinuria
• Hemoglobinuria

15
Causes of Perioperative Oliguria Postrenal
(Obstructive Uropathy)

• Bilateral ureteral obstruction
• Extravasation from bladder rupture
• Prostatism

16
Differential Diagnosis of Perioperative Oliguria

• Prerenal Renal
• Urine sodium lt 40 gt 40
• Urine osmolarity gt 400 250-300
• Urine/plasma gt 1 . 8 lt 1 . 1
• osmolarity

17
Patients at Risk of Perioperative Renal Failure

• Renal disease Multiple trauma
• Liver disease Congestive heart
  
• Hypovolemia failure
• Sepsis Advanced age

18
Operative Risks of Renal Failure

• Abdominal aneurysm resection
• Cardiopulmonary bypass

19
Treatment of Acute Renal Failure

• Fluid Challenge
• Dopamine infusion
• (3-5 mcg/kg/min)
• Diuretics
• Mannitol 12 . 5 g
• Furosemide 5 mg

20
Renal Disease (1)

• Glomerulonephritis
• Acute (often post-streptococcal)
• Goodpasture syndrome (vasculitis)
• Nephrotic syndrome (gross proteinuria)
• Interstitial nephritis (drug allergy)

21
Renal Disease (2)

• Polycystic kidneys
• Fanconi syndrome
• Bartter syndrome

22
Renal Disease (3)

• Renal hypertension
• Uric acid nephropathy
• Hepatorenal syndrome

23
Anesthesia for ESWL

• Immobilization
• Analgesia to T6 (regional technic)
• Effects of water immersion
• Cardiac dysrhythmias (shock waves)

24
TURP Syndrome

• Cardiovascular changes (hypervolemia)
• CNS disturbances, dysrhythmias (dilutional
  hyponatremia)

25
TURP SyndromeSigns of Hemodilution

• Serum sodium
• lt 120 mEg/L
• Hematocrit decreased

26
Anesthesia for TURP

• Spinal preferred (level to T 10)
• Early detection of excessive fluid absorption
• Early detection of bladder perforation
• Postoperative analgesia (opioid)

27
Renal TransplantationPreoperative

• Hemodialysis
• Blood glucose value
• (diabetic patient)

28
Renal TransplantationIntraoperative

• Fluid 5 glucose with 0.45 NaCl
• Mannitol 12.5 g increments

29
Renal Insufficiency

• Threshold
• loss of 60 of nephrons
• Uremia
• loss of 90 of nephrons

30
Anesthetic Induction

• CNS hypersensitivity
• Hypovolemia

31
Fluid Management

• Preoperative hydration (balanced salt solution
  10-20 ml/kg)
• Intraoperatively 3-5 ml/kg/h
• Maintain urine output gt 0.5 ml/kg/h
• Avoid diuretics

32
Fluid Management(Anuric Patient)

• Replace insensible losses with 5 D/W

33
Renal TransplantationHazards and Complications

• Cardiac arrest (acute hyperkalemia)
• Acute immunologic rejection (DIC)
• Hematoma
• Delayed signs of rejection (fever, oliguria)