A 58-year-old man with severe aortic stenosis is scheduled for transurethral resection of the prostate (TURP). Regarding contraindications and complications of spinal anesthesia in this patient, all of the following are true EXCEPT:

Explanation

## Analysis of Spinal Anesthesia in High-Risk Cardiac Patient Undergoing TURP ### Clinical Context A 58-year-old with severe aortic stenosis is at high risk for hemodynamic collapse with spinal anesthesia because: - Fixed cardiac output (stenotic valve cannot increase flow in response to decreased SVR). - Sympathetic blockade causes vasodilation and venous pooling, reducing preload and SVR. - Result: severe hypotension, reduced coronary perfusion, and potential cardiogenic shock. ### Correct Statements (Options 0, 1, 3) **Option 0: Relative contraindication due to sympathetic blockade** ✓ - Spinal anesthesia causes sympathetic blockade (T1–S5 fibres blocked). - In fixed-output states (aortic stenosis, hypertrophic cardiomyopathy, constrictive pericarditis), this is poorly tolerated. - General anesthesia with careful titration or epidural (slower onset) is preferred. **Option 1: Hyperbaric bupivacaine for TURP** ✓ - Hyperbaric solutions (dextrose-containing) are denser than CSF and settle dependently. - This allows the anesthetist to position the patient and control the level of block (e.g., lithotomy position for sacral spread). - Isobaric solutions have unpredictable spread and are less suitable for TURP. **Option 3: PDPH more common in young patients and parturients** ✓ - PDPH incidence is inversely related to age (young: ~10–15%; elderly: ~1–2%). - Parturients (pregnant and postpartum women) have higher CSF pressure and dural compliance, increasing PDPH risk. - Elderly patients have reduced CSF pressure and dural compliance, lowering PDPH risk. ### Incorrect Statement (Option 2: TURP Syndrome Unrelated to Local Anesthetic Choice) ✗ **Key Point:** TURP syndrome is caused by **excessive absorption of hypotonic irrigation fluid** (not the local anesthetic), but the choice of local anesthetic agent DOES influence the risk and severity. **Why the statement is wrong:** - TURP syndrome occurs when large volumes of hypotonic fluid (1.5% glycine, distilled water, or 1.5% sorbitol) are absorbed systemically during prolonged resection. - This causes hyperammonemia (if glycine used), hyponatraemia, hyperammonaemia, cerebral oedema, and seizures. - **However**, the local anesthetic agent IS relevant: - **Spinal anesthesia** with hyperbaric bupivacaine limits the duration of the block (~90–120 min), reducing operative time and fluid absorption risk. - **Epidural anesthesia** allows longer operative times, increasing TURP syndrome risk. - **General anesthesia** masks early warning signs (restlessness, confusion) of TURP syndrome. - The choice of local anesthetic (lidocaine vs. bupivacaine) and route (spinal vs. epidural) directly influence TURP syndrome risk. **High-Yield:** TURP syndrome is a **fluid-related complication**, not a local anesthetic toxicity issue, but the anesthetic technique chosen affects the risk of fluid overload. **Clinical Pearl:** TURP syndrome prevention includes: 1. Limiting operative time to <90 minutes. 2. Using hyperbaric spinal anesthesia (shorter block duration). 3. Minimizing irrigation fluid volume. 4. Using isotonic irrigants when possible (e.g., normal saline for bipolar TURP). | Feature | Spinal Anesthesia | Epidural Anesthesia | General Anesthesia | |---------|-------------------|---------------------|--------------------| | Block duration | 90–120 min (fixed) | Prolonged (variable) | Prolonged | | TURP syndrome risk | Lower | Higher | Masks early signs | | Operative time limit | Strict | Flexible | Flexible | | Ideal for TURP | Yes | No | No (unless contraindicated) |