Urologic

Question 1

The kidneys receive ___% CO

Answer 1

20-25%

Question 2

How do the kidneys maintain homeostasis?

Answer 2

Filtration
Reabsorption
Tubular excretion

Question 3

Normal GFR

Answer 3

125mL/min

Up to 99% filtrate reabsorbed

Question 4

Renal Hormones

Answer 4

Aldosterone
ADH
Angiotensin
ANP
Vitamin D
Prostaglandins

Question 5

Bowman’s Capsule

Answer 5

Filtration

Question 6

Proximal Tubule

Answer 6

Reabsorption

Question 7

Loop of Henle

Answer 7

Concentration

Question 8

Distal Tubulue

Answer 8

Reabsorption

Question 9

Collecting Duct

Answer 9

Last chance to concentrate urine & reabsorb H2O

Question 10

Urine Specific Gravity

Answer 10

1.01 - 1.025

pH 4.6-4.9

Question 11

Anesthesia Impact

Answer 11

Anesthetic drugs depress normal renal function
↓RBF 30-40%
Autoregulation impairment
↓GFR, urinary flow, & electrolyte secretion
Similar changes after spinal or epidural anesthesia
- Sympathetic blockade & ↓BP

Question 12

Volatile Anesthetics Effect

Answer 12

Mild ↑renal vascular resistance
Compensatory mechanisms in response to ↓CO/SVR
Goal - preop hydration, ↓volatile agents, maintain BP, & attenuate ↓RBF/GFR

Question 13

Sevoflurane

Answer 13

Associated w/ elevated fluoride levels
Degraded by absorbents → compound A (vinyl ether)
Compound A nephrotoxicity
↑FGF to prevent risk 1L/min 2 MAC-hours max
↓gas concentration
Utilize carbon dioxide absorbents

Question 14

Isoflurane

Answer 14

Not associated w/ nephrotoxicity

Question 15

Desflurane

Answer 15

Resists biodegradation

Not associated w/ nephrotoxicity

Question 16

Fluoride Ion Toxicity

Answer 16

Fluoride interferes w/ Na+/Cl¯ active transport in the loop of Henle
Potent vasoconstrictor → negative effects on CV
Inhibit enzyme systems (ADH)
Nephrotoxicity - proximal tubular swelling & necrosis

Question 17

Nephrotoxicity S/S

Answer 17

Polyuria
Hypernatremia
Serum hyperosmolality
↑BUN/creatinine
↓creatinine clearance 
Related to dosage, duration, & peak fluoride concentrations

Question 18

Acute Kidney Injury

Answer 18

Renal functional or structural abnormality that occurs w/in 48hrs
↑creatinine 0.3mg/dL or 50%
UOP <0.5mL/kg/hr x 6 hours

Question 19

Pre-Renal AKI

Answer 19

Renal hypoperfusion w/o parenchymal damage
- Hemorrhage, vomiting/diarrhea, diuretics, sepsis/shock, CHF, NE, NSAIDs, ACEi
Early identify & treatment causes = BEST outcomes

Question 20

Intra-Renal AKI

Answer 20

Damage to renal tissue
- Tubular injury d/t hypoperfusion, myoglobin, chemotherapy, infections, lymphoma, toxemia (pregnancy), vasculitis
Most difficult to treat w/ worst oucomes

Question 21

Post-Renal AKI

Answer 21

Due to urinary tract obstruction
- Renal calculi, peritoneal mass, prostate/bladder urethra tumor, fibrosis, hematoma, strictures
Good prognosis w/ early identification

Question 22

AKI Risk Factors

Answer 22

Hypovolemia, electrolyte imbalance, contrast dye
Aging - preop renal dysfunction or >50yo
Comorbidities - cardiac or hepatic failure
Surgical procedures - aortic cross-clamp, cardiac bypass, arteriography, intra-aortic balloon pump
Emergency or high risk procedures - ruptured AAA, ischemic time, high volume blood transfusion

Question 23

AKI Preop Tx

Answer 23

Replace intravascular fluid deficits

• Balanced salt solution minimizes ​ADH & renin-angiotensin-aldosterone release
• Attenuate surgical stress

A-line, TEE, CVP, foley catheter

Question 24

AKI Periop Tx

Answer 24

*Fluid replacement
Colloids vs. crystalloids
Goal 0.5-1mL/kg/hr
*Improve CO
*Normalize SVR

Avoid diuretics to treat oliguria
Prevention & management
- Prevent prolonged hypotension
- Prophylaxis
- Initial insult duration & severity determines AKI

Admin volume NS to euvolemia
↓afterload ↑CO
Limited renal ischemia duration

Question 25

Chronic Kidney Disease

Answer 25

Renal function ↓10% per decade GFR < 60mL/min for 3 MONTHS S/S & abnormal labs do not appear until <40% normal functioning nephrons remain 95% loss renal function → uremia, volume overload, CHF

Question 26

CKD Systemic Effects | Cardiovascular

Answer 26

HTN & CHF 90% volume dependent 10% 2° ↑renin Pericardial effusion Ischemic heart disease = most common cause death Outcomes better w/ CABG than angioplasty Pericarditis in patients w/ severe anemia

Question 27

CKD Systemic Effects | Respiratory

Answer 27

Respiratory depression 2° delayed clearance

Question 28

CKD Systemic Effects | Neurologic

Answer 28

Fatigue & weakness - early complaints Autonomic neuropathy Disequilibrium syndrome → seizures, stupor, & coma

Question 29

CKD Systemic Effects | Hematologic

Answer 29

Normochromic, normocytic anemia ↓erythropoietin production ↓erythrocyte life 2° dialysis Blood loss from frequent sampling Prolonged bleeding ↓clotting factors ↓platelet function Dialysis w/in 24hrs corrects Desmopressin ↑factor VIII levels RBC transfusion citrate binds to Ca2+ → hypocalcemia

Question 30

CKD Systemic Effects | Gastrointestinal

Answer 30

Dialysis patients ↑risk GI bleeding | Mucosal changes & inflammation

Question 31

CKD Systemic Effects | Infection

Answer 31

Protein malnutrition | Neutrophil, monocyte, & macrophage changes

Question 32

CKD Systemic Effects | Endocrine

Answer 32

Hyperparathyroidism (compensatory mechanism) | Adrenal insufficiency

Question 33

CKD Systemic Effects | Electrolyte

Answer 33

Na+ wasting Hypocalcemia Hyperkalemia

Question 34

Hyperkalemia

Answer 34

``` K+ 7-8mEq/L → fatal dysrhythmias Treatment: - 25-50g dextrose - 10-20 units regular insulin - 50-100mEq sodium bicarbonate - Hyperventilate ↓CO2 Check preop levels ```

Question 35

CKD Anesthetic Considerations | Preop

Answer 35

Labs & diagnostic tests Continue antihypertensive medications Renal insufficiency - preop volume replacement

Question 36

CKD Anesthetic Considerations | Periop

Answer 36

A-line Regional vs. general anesthesia Central line Fluid management

Question 37

CKD Anesthetic Considerations | Postop

Answer 37

Dialysis w/in 24-36hrs

Question 38

CKD Anesthetic Considerations | Fluid Management

Answer 38

UOP 0.5-1mL/kg/hr Treat mildly compromised function w/ balanced salt solution 3-5mL/kg/hr w/ 500mL bolus PRN LR & other K+ containing solutions contraindicated when patient UOP <100mL/day Reserve blood products for patients requiring ↑oxygen-carrying capacity Renal insufficiency or ESRD - Replace fluid volume deficit preop - Intraop losses >15% EBL replace w/ 1:1 colloid - Crystalloid w/o K+ 2-3mL/kg/hr Dialysis patient - Insensible losses replace w/ 5-10mL/kg D5W - Replace urine produced w/ 0.45% saline

Question 39

Dialysis Physiologic Effects

Answer 39

Hypotension Muscle cramping Anemia Nutritional depletion

Question 40

Serum Creatinine

Answer 40

0.7-1.5mg/dL | ↓GFR 50% → serum creatinine doubles

Question 41

BUN

Answer 41

Blood urea nitrogen 10-20mg/dL BUN:creatinine ratio 10:1

Question 42

Creatinine Clearance

Answer 42

``` MOST RELIABLE RENAL FUNCTION TEST 95-150mL/min Measure glomerular ability to excrete creatinine in urine Mild dysfunction 50-80mL/min Moderate <25mL/min <10mL/min requires dialysis ```

Question 43

Pharmacologic Considerations

Answer 43

↓protein binding ↑sensitivity Morphine not removed by dialysis Meperidine metabolite Normeperidine not removed by dialysis H2 blockers dependent on renal excretion ↓dose

Question 44

Regional Anesthesia

Answer 44

Well-tolerated Block DOA not impacted by renal failure Spinal/epidural - obtain platelet count, PT/PTT, coags Concerns include intolerance, coagulopathy, peripheral neuropathy, & infection risk

Question 45

General Anesthesia Drugs

Answer 45

``` IV ↑Vd ↓protein binding Ketamine & benzos less protein bound Propofol = safe Dexmedetomidine hepatic clearance Remifentanil ↓plasma esterases ↓clearance ESRD patients ```

Question 46

NMBs

Answer 46

``` Succinylcholine - ↑K+ 0.5mEq/L - Cholinesterase deficiency (uremic patients) Pancuronium - 80% renal excretion Atracurium/Cisatracurium/Mivacurium - DOA not impacted in renal failure Vecuronium - 30% renal excretion - Effects rapidly reversed w/ dialysis Rocuronium - Renal failure ↓clearance 40% → longer DOA ```

Question 47

Cystoscopy

Answer 47

``` Any urologic procedure not open Cystoscope to examine urethra & bladder Diagnostic or treatment procedures Position = lithotomy Void prior to discharge home ```

Question 48

Extracorporeal Shock Wave Lithotripsy

Answer 48

ESWL Nephrolithiasis (renal calculi or kidney stones) <5mm pass w/o intervention 5-10mm medical management >10mm requires intervention Non-invasive treatment that uses high-energy ultrasound waves to breakup calculi - Outpatient procedure under GA - R wave used to trigger shocks (EKG placement) - Hematuria common

Question 49

ESWL Contraindications

Answer 49

Active UTI Uncorrected bleeding disorder or coagulopathy Distal obstruction Pregnancy

Question 50

ESWL Complications

Answer 50

Dose-dependent hemorrhagic lesions Perforation, rupture or damage to colon, hepatic structures, lungs, spleen, pancreas, abdominal aorta, or iliac veins Hematuria develops in most patients Diabetes, new-onset HTN, or ↓renal function

Question 51

ESWL Anesthetic Considerations

Answer 51

GA rapid onset & able to control patient movement Spinal/epidural level T4/T6 MAC Topical LA Discontinue ASA, anticoagulants, platelet inhibitors, & NSAIDs 7-10 days prior to procedure ↓hematuria risk Document negative urine culture HCG on appropriate patients Laser eye protection

Question 52

Percutaneous Nephrolithotomy

Answer 52

Procedure to remove kidney stones <25mm GA & postop hospitalization (admit inpatient) Prone or supine position

Question 53

Percutaneous Nephrolithotomy | Complications

Answer 53

Pain, fever, UTI, renal colic, septicemia, bleeding, pneumothorax/hemothorax, anaphylaxis

Question 54

TURP

Answer 54

Transurethral resection of prostate (BPH) Most common surgical procedure performed in men >60yo Scope placed through urethra to cut away obstructing prostate lobes Bladder distended & continuous irrigation used ANESTHETIC RISKS R/T PATIENT AGE & ASSOCIATED COMORBIDITIES

Question 55

TURP Anesthetic Considerations

Answer 55

``` Commonly performed under GA Spinal anesthesia preferred to assess patient mental status S/S complications more easily detected PREVENTION most important approach - Avoid trendelenburg position - Limit resection <1 hour - Place irrigation solution <60c, above prostate - Monitor electrolytes - Regional technique w/ sedation ```

Question 56

TURP Irrigation Solutions

Answer 56

Distilled water 1° Saline Cytal (sorbitol & mannitol) Glycine → toxicity

Question 57

TURP Complications

Answer 57

``` Volume overload w/ pulmonary edema Dilutional hyponatremia w/ hypoosmolality → cerebral swelling ↑ICP Cardiac effects Renal toxicity (glycine) Hyperglycemia Hypothermia Glycine absorption Bleeding (difficult to assess d/t irrigation) Bladder perforation Infection Skin burns TURP syndrome ```

Question 58

TURP Syndrome

Answer 58

Rare but significant complication Mortality up to 25% Fluid absorbed through prostate

Question 59

TURP Syndrome S/S

Answer 59

Combination water intoxication, fluid overload, & hyponatremia Water intoxication - confusion, restlessness, seizure, lethargy, coma, dilated sluggish pupils Fluid overload - HTN, bradycardia, arrhythmia, angina, pulmonary edema, CHF, hypotension Hyponatremia - CNS changes, widened QRS, T-wave inversion Glycine toxicity - N/V, headache, transient blindness, myocardial depression

Question 60

TURP fluid absorption dependent on _____

Answer 60

Resection size & duration Irrigation solution pressure Number venous sinuses open at once Provider experience

Question 61

TURP Fluid Absorption

Answer 61

30mL fluid absorbed per minute Up to 8L in 2 hours 1L irrigant uptake ↓serum Na+ 5-8mEq/L Serum Na+ <120mEq/L associated w/ severe reactions

Question 62

Glycine Absorption

Answer 62

Glycine - amino acid Acts as inhibitory transmitter Excessive absorption → N/V, fixed & dilated pupils, headache, weakness, muscle incoordination, TURP blindness, seizures, hypotension

Question 63

TURP Syndrome Treatment

Answer 63

``` Early recognition Notify surgeon to stop surgery Correct hyponatremia Furosemide 20mg IV Labs - electrolytes, glucose, Hct, creatinine, ABG, 12-lead EKG Midazolam 1mg PRN seizures Pulmonary edema → intubate PRBCs Investigate DIC or 1° fibrinolysis ```

Question 64

Hyponatremia Correction

Answer 64

3-5% saline <100mL/hr ↑Na+ 0.5mEq/hour or 8mEq/day Goal Na+ >120mEq/L Rapid reversal → osmotic demyelination syndrome

Question 65

Laparoscopic Urologic Surgery | Anesthetic Considerations

Answer 65

Pneumoperitoneum 15mmHg Urologic system retroperitoneal (communicates w/ thorax) → risk subcutaneous emphysema Alterations in renal & hepatic perfusion CO2 absorption → potential acidosis ↑intraabdominal & intrathoracic pressures Hemorrhage

Question 66

Robotic Urologic Surgery

Answer 66

Upper tract - simple or radical nephrectomy, radical nephroureterectomy, nephron-sparing Pelvic - radical cystectomy, radical prostatectomy

Question 67

Robotic Urologic | Anesthetic Considerations

Answer 67

``` Steep trendelenburg Lithotomy (prostatectomy) Arms tucked at sides Airway assessment BEFORE extubation Duration 3-4 hours EBL <300mL Limit fluids until urethra reconnected 2L total Large bore PIVs & A-line DVT prophylaxis, eye protection, OG tube, Bair hugger, antibiotics, dexamethasone Remifentanil infusion common ```

Question 68

Nephrectomy

Answer 68

``` Open vs. laparoscopic Lateral jack-knife position (kidney rest) Cardiovascular compromise 3rd spacing & edema Hemodynamic monitoring A-line Postop pain management ```

Question 69

Renal Transplant

Answer 69

ESRD treatment Donors living or deceased Most frequent solid organ transplant today 5-year survival rate 70% Transplanted kidney placed in R or L extraperitoneal fossa (R preferred) Attached via vascular anastomoses external iliac artery & vein & ureter anastomosed to bladder GA with A-line & CVP monitoring Propofol & Cisatracurium Immunosuppressant therapy