TURP - Basics and Anaesthetic Considerations

I. INTRODUCTION

II. INDICATIONS FOR TURP

• Bladder outlet obstruction due to BPH
• Recurrent urinary retention
• Recurrent urinary tract infections
• Bladder calculi secondary to BPH
• Gross haematuria due to BPH
• Prostate cancer (palliative relief of obstruction in non-surgical candidates)

III. PROCEDURE - BASICS

Monopolar vs. Bipolar TURP

IV. IRRIGATING SOLUTIONS

• Glycine is the most commonly used irrigant for monopolar TURP
• All these fluids are hypotonic - significant water absorption can occur
• Fluid absorption rate increases with higher irrigation bag height (higher hydrostatic pressure)
• Average absorption: 10-30 mL per minute of resection; up to 6-8 L in a 2-hour procedure

V. TURP SYNDROME

Definition

• Circulatory fluid overload
• Dilutional hyponatraemia and hypo-osmolality
• Solute toxicity (glycine, ammonia)

Incidence

• Mild-to-moderate TURP syndrome: 0.78-1.4%
• Severe (serum Na⁺ < 120 mEq/L): mortality up to 25%
• Overall clinical incidence: 10-15% of cases (Miller's 10e)

Pathophysiology

1. Fluid absorption through opened prostatic venous sinuses
2. Rapid intravascular volume expansion → initial hypertension and bradycardia
3. Hypo-osmolality → osmotic shift of water into brain → cerebral oedema
4. Progressive hyponatraemia → eventually hypotension, pulmonary oedema, cardiac arrest
5. Hyponatraemia + endotoxin release → metabolic acidosis and hypotension

Factors Governing Fluid Absorption (Miller's 10e)

1. Height of irrigation bag above table - governs hydrostatic pressure
2. Bladder distension
3. Extent of opened venous sinuses (gland size, vascularity)
4. Duration of surgery

Clinical Features (by Na⁺ level)

Glycine-Specific Toxicity

• Glycine is an inhibitory neurotransmitter in the retina and spinal cord
• Causes transient blindness with non-reactive or sluggish pupils (retinal effect - unlike cerebral oedema where papillary reflexes are preserved)
• Metabolised to ammonia → hyperammonaemia → encephalopathy
• Also a negative inotrope - contributes to cardiovascular depression

Prevention of TURP Syndrome

1. Use bipolar TURP with isotonic saline (eliminates hypo-osmolar risk)
2. Limit procedure duration to <90 minutes (safest) - complications increase significantly beyond 120 minutes
3. Keep irrigation bag height low (< 60 cm above table) - limits intravesical pressure to <15-25 mmHg
4. Monitor fluid balance: halt surgery if 750-1000 mL absorbed in females or ≥1000 mL in males; terminate if >2000 mL absorbed
5. Use regional anaesthesia for early detection of neurological symptoms
6. Limit prostate size for TURP (<80 g ideal)

Treatment of TURP Syndrome

1. Stop the procedure immediately
2. Fluid restriction
3. Furosemide IV - promotes free water excretion if volume overloaded
4. Serum Na⁺ measurement - guide therapy severity
5. Hypertonic saline (3% or 5%) if symptomatic hyponatraemia (seizures, coma) - correct Na⁺ by no more than 8-10 mEq/L per 24 hours to avoid osmotic demyelination
6. Midazolam 2-4 mg IV to terminate seizures
7. Endotracheal intubation if mental status does not normalise (aspiration risk)
8. Haemodialysis if osmolality is normal or near-normal (with neurological symptoms)
9. Magnesium for seizures - counteracts dilutional hypomagnesaemia and glycine's NMDA-excitatory effects

VI. OTHER COMPLICATIONS OF TURP

A. Haemorrhage

• Average blood loss: 3-5 mL/gm of resected tissue
• Major risk factors: gland size >45 g, procedure >90 min, recent infection
• Blood type and screen adequate for most; crossmatch for large glands/anaemia

B. Hypothermia

• Large volumes of room-temperature irrigant are a major source of heat loss
• Irrigating solutions must be warmed to body temperature
• Postoperative shivering may dislodge clots and promote bleeding (Morgan & Mikhail 7e, p. 1305)

C. Bladder Perforation (incidence <1%)

• Extraperitoneal (more common): poor return of irrigant; awake patient reports nausea, diaphoresis, retropubic/lower abdominal pain
• Intraperitoneal: sudden unexplained hypotension or hypertension, shoulder pain, generalised abdominal pain; requires open surgical repair
• Vagal-mediated acute bradycardia is a classic warning sign

D. Coagulopathy / DIC

• Thromboplastin release from prostatic tissue → DIC
• Metastatic prostate cancer → primary fibrinolysis (fibrinolytic enzyme secretion)
• Treatment: ε-aminocaproic acid (Amicar) or tranexamic acid for fibrinolysis; heparin + clotting factor replacement for DIC

E. Septicaemia

• Prostate often colonised; venous sinus opening allows bacteraemia
• Prophylactic antibiotics: gentamicin, levofloxacin, or cefazolin prior to incision
• Can rarely progress to septic shock

F. Positioning Complications (Lithotomy)

• Decreased pulmonary compliance, cephalad diaphragm shift, reduced FRC, TV, and VC
• Increased cardiac preload
• Nerve injuries: common peroneal, sciatic, femoral nerves

VII. PREOPERATIVE ASSESSMENT

• Cardiovascular disease (HTN, CAD, CCF)
• Diabetes mellitus
• Chronic renal impairment (from chronic obstruction)
• Respiratory disease (COPD)
• Medications: anticoagulants (need bridging), alpha-blockers, 5-alpha reductase inhibitors

• CBC, serum electrolytes (especially Na⁺, K⁺), renal function tests
• Coagulation profile (PT, aPTT, INR)
• ECG, chest X-ray
• Blood group and screen (crossmatch if large gland or anaemia)
• Urine culture (treat active UTI before surgery)

VIII. ANAESTHETIC TECHNIQUE

A. Choice of Anaesthesia - Spinal (Subarachnoid Block) is the Technique of Choice

B. Target Sensory Level

• T10 provides satisfactory anaesthesia for TURP
  • Blocks sensory transmission from the prostate and bladder neck
  • Eliminates sensation of bladder distension
• Higher levels (above T10) may mask symptoms of accidental bladder or capsular perforation (abdominal/shoulder pain)

C. Spinal vs. Epidural for TURP

D. General Anaesthesia

• Regional technique is contraindicated (coagulopathy, patient refusal, spinal deformity, technical failure)
• Concerns about sacral nerve coverage
• Disadvantage: masks early neurological signs of TURP syndrome - sedatives or GA induction may lead to missed diagnosis and death

E. Blood Loss and Anaesthesia

• Regional anaesthesia may reduce blood loss by lowering central and peripheral venous pressures
• However, spinal anaesthesia (by reducing CVP) may allow greater absorption of irrigating solution compared to GA
• Studies conflict: no definitive evidence of reduced blood loss with one technique over the other

F. Monitoring

• Standard ASA monitors
• Temperature monitoring (hypothermia from irrigant)
• Urine output monitoring
• Fluid balance chart (irrigation in vs. irrigation out)
• Serum Na⁺ if TURP syndrome suspected
• Awake patient as the best neurological monitor

IX. POSTOPERATIVE CONSIDERATIONS

• Watch for delayed TURP syndrome (onset up to 24 hours post-procedure)
• Clot retention requiring irrigation
• Post-TURP hypothermia and shivering (dislodges clots)
• Bleeding - monitor Hb, transfuse if needed
• UTI prophylaxis continued
• Renal function monitoring

X. MODERN ALTERNATIVES REDUCING TURP SYNDROME

• Bipolar TURP - uses isotonic saline; eliminates hypo-osmolar syndrome but fluid overload risk remains
• Laser vaporisation of the prostate (e.g., GreenLight laser, Holmium laser) - no non-conductive irrigant required; can use normal saline; lower blood loss; reduced absorption risk
• Transurethral incision of the prostate (TUIP) - for smaller glands; less morbidity
• Laser techniques: coagulative properties reduce blood loss and transfusion rates

XI. KEY EXAM POINTS SUMMARY

1. Spinal anaesthesia is the technique of choice for TURP - T10 sensory level required
2. TURP syndrome = absorption of ≥2 L hypotonic irrigant → fluid overload + hyponatraemia + solute toxicity
3. Glycine 1.5% is the most widely used irrigant; causes transient blindness (non-reactive pupils) and hyperammonaemia
4. Serum Na⁺ <120 mEq/L → cardiovascular compromise; <110 mEq/L → seizures; ~100 mEq/L → cardiac arrest
5. Treatment: stop surgery, fluid restriction, furosemide, hypertonic saline (3%) for symptomatic cases
6. Rate of Na⁺ correction: <8-10 mEq/L per 24 hours to prevent osmotic demyelination syndrome
7. Procedure time >90 min significantly increases morbidity; safest window is under 90 minutes
8. Irrigation bag height governs absorption rate - keep <60 cm above table
9. Bladder perforation: extraperitoneal (pain + poor irrigant return) vs. intraperitoneal (sudden hypotension + shoulder pain)
10. Hypothermia from room-temperature irrigant - warm all solutions to body temperature