The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Anesthetic Considerations for GU & Renal Surgery
Donald M. Voltz, MD
Renal Functions
Waste Removal Fluid Regulation
Regulation of Electrolytes
Blood Pressure Regulation
Acid-Base Balance
Hormone Production
Case Studie for Renal Pathophysiology
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Clinical Case
58 year-old male scheduled for thrombectomy of his left arm AV-graft. • Hypertension • ESRD – on HD qM,W,F (last 3 days ago0 • Diabetes Mellitus
Renal Concerns?
– Fluids – Electrolytes – Acid-Base Balance – Hormones – Blood Pressure Regulation
Fluid Balance
• Unable to remove excess free water • May present with Pulmonary Edema • Dialysis to restore patients to less than “dry” weight
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Electrolytes
K+ HCO3-
Complications of Renal Failure
• • • • • • • • • • • • Pericarditis, cardiac tamponade Congestive heart failure Hypertension Platelet dysfunction Gastrointestinal loss of blood; duodenal or peptic ulcers Hemorrhage Anemia Hepatitis B, hepatitis C, liver failure Decreased functioning of white blood cells and immune system Infection Peripheral neuropathy Seizures • • • • • • • • Encephalopathy, nervous system damage, dementia Weakening of the bones, fractures, joint disorders Permanent skin pigmentation changes Skin dryness, itching/scratching with resultant skin infection Changes in glucose metabolism Changes in electrolyte levels Decreased libido, impotence Miscarriage, menstrual irregularities, infertility
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Treatment of Renal Failure
• • • • Hemodialysis Peritoneal Dialysis Kidney Transplantation Nothing
Genital/Urinary Anatomy
• External Anatomy – Penis, scrotum, testicles • Urethra • Bladder • Ureter’s • Kidney’s
Genital/Urinary Anatomy - Male
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Genital/Urinary Anatomy - Female
Positioning in GU Surgery
Lithotomy most common position.
Lithotomy Position
• Proper position to prevent injury
– Legs positioned simultaneously. – Padding lateral thigh to protect common peroneal nerve. – Excessive flexion – Obturator nerve
• Physiologic changes with lithotomy
– – – – Decreased FRC Increases venous return Hypotension when legs returned to normal Increased MAP
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Genital/Urinary Surgery
• • • • • • • • Cystoscopy Ureteroscopy Cystecomy Transurethral Bladder/Prostate Surgery Prostate Surgery Nephrostomies Nephrectomies Lithotripsy
Cystoscopy
What is it?
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Patient Characteristics
• • • • Hematuria Bladder Tumors Kidney Stones Ureteral Obstruction
Patient Positioning
• Lithotomy • Supine
Anesthetic Considerations
• • • • Tend to be short cases General anesthetic typical choice Regional can be used (T10 level) Can do under local anesthesia (♀>♂)
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Anesthetic Choices
• Cystoscopy may be coupled with ureteroscopy • Important patients don’t move
Transurethral Surgery
Transurethral Surgery
• Bladder (TURBT)
– – – – Bladder tumors Resection of tumor Patients age ranges Mortality < 1%
• Prostate (TURP)
– BPH – Resection of hypertrophied prostate tissue – Patients > 60 yrs – Mortality 0.2 – 6 %
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Patient Characteristics
• TURP patients – 30-60% have cardiac or pulmonary disease • Potential for blood loss with large prostates (>40 ml) • Mortality correlated with ASA classification • ± renal disease
Patient Positioning
• Lithotomy
– TURBT – TURP
Anesthetic Considerations
• TURP
– Hemorrhage – TURP Syndrome – Bladder perforation – Hypothermia – Septicemia – DIC
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
TURP Syndrome
• Results from absorption of irrigation fluid • Fluid leads to dilution of electrolytes
– – – – – Hyponatremia Decreased serum osmolarity Fluid overload Hemolysis Solute problems
• • • • Hyperglyinemia Hyperammonemia Hyperglycemia Volume expansion
TURP Irrigation Solutions
• Non-electrolyte, hypotonic solutions
– Water – Glycine – Sorbitol – Mannitol
Water Intoxication
• Absorption of fluid
– Duration of resection (20 ml/min) – Fluid Height (pressure)
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Hyponatremia
• Sx occur when Na < 120 mEq/l
– Seizures – Cardiac conduction problems – Intravascular hemolysis
Solute Toxicity
• Hyperglycinemia
– Cardiac & Neurologic toxicity – Glycine inhibitory neurotransmitter – Can lead to transient blindness – Breakdown leads to high ammonia levels
Rx of TURP Syndrome
1. Stop resection 2. Treat hypoxia and hypotension 3. Eliminate excess water
1. Fluid restrict 2. Loop diuretics
4. Treat seizures 5. Slow correction of hyponatremia
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Other Complications
• Hypothermia
– Warm irrigation
• Bladder perforation
– Abd pain – Hypo or hypertension – bradycardia
Other Complications
• Coagulopathy
– Release of thromboplastins – Dilutional thrombocytopenia – Tumors can secrete fibrinolytic enzymes
• Amicar
• Septicemia
– Prostate can be colonized with bacteria
Anesthetic Choices
• Regional
– Spinal or Epidural – T10 level – Dec incidence of DVT – Earlier recognition of TURP syndrome or bladder performation
• General
– No difference in mortality, cognitive fxn, blood loss
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Radical Cystectomy
What is it?
• Treatment for Bladder cancer • Major operation (4-6 h) • Complete removal of bladder and surrounding tissue • Construction of some urinary diversion follows
Patient Characteristics
• Maintain urine flow • Hemodynamic monitoring
– A-line – CVP
• Blood loss can be high
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Anesthetic Considerations
• General
– Generally the choice – Long operation – Concern for Blood loss
• Regional
– Can lead to unopposed parasympathetic state
• Leads to contraction of bowel
Lithotripsy
What is it?
• Treatment for Kidney Stones • Open invasive to noninvasive techniques
– Stone extraction – Intracorporeal lithotripsy - lasers – Extracorporeal lithotripsy – shock waves
• ESWL • Repetitive high-energy sound waves directed at stone • Waves transmitted through tissue without damage unless there is air interface
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Patient Positioning
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Anesthetic Considerations
• Cardiac arrythmias
– Shock can damage pacemaker or AICD – Synchronize shock with R wave
Anesthetic Choices
• Depends on type of Lithotripsy • Pain results from small amount of energy entering skin • Regional or General for older units • Light to deep sedation for newer units • Fluid and diuretic to promote urine flow
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Prostate Cancer
Prostate Cancer
• Most common cancer in me • Treatment varies on disease aggressiveness
– Surveillance – Hormonal treatment – Radiation treatment – Surgical Removal
Prostatectomy
• Laproscopic • Radical retropubic prostatectomy
– With lymph node dissection
• Perineal prostatectomy • Bilateral orchiectomy
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Renal Cancer
Renal cell carcinoma
• Paraneoplastic syndromes
– Erythrocytosis – Hypercalcemia – Hypertension – Nonmetastatic hepatic dysfunction
• Peak incidence 50 – 60 year old • Male:Female 2:1 • Tumor can extend into renal vein
Renal cell carcinoma
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The Physiology of Anesthesia Practice Donald M. Voltz, MD 8 March 2006
Renal cell carcinoma
• Radical Nephrectomy • Radical Nephrectomy with tumor thrombus removal • Partial Nephrectomy
Anesthetic Considerations
• Positioning
– Flank approach – Thoracoabdominal with large tumors
• Potential for high blood loss • Reflex renal constriction can impact fxn of remaining kidney • Use of manitol to promote diuresis of normal kidney
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