What are the recommended anesthesia considerations for geriatric patients undergoing Transurethral Resection of the Prostate (TURP)?

Anesthesia Considerations for Geriatric Patients Undergoing TURP

For geriatric patients undergoing TURP, spinal anesthesia is the preferred technique because it enables early detection of TUR syndrome through preserved consciousness, while requiring dose reduction (30-50% lower than standard) and meticulous hemodynamic management to prevent hypotension and its associated complications. 1, 2

Choice of Anesthetic Technique

Spinal Anesthesia as First-Line

• Spinal anesthesia is optimal for TURP because conscious patients can report early symptoms of TUR syndrome (nausea, visual disturbance, apprehension) before progression to serious complications. 2
• In a 15-year review of 1,502 TURPs, all 48 cases of TUR syndrome (3.2% incidence) were detected early through patient-reported symptoms under spinal anesthesia, with nausea being the earliest sign in 44% of cases. 2
• The sensory block should not exceed T10 level to maintain hemodynamic stability while providing adequate surgical anesthesia. 3

Regional vs. General Anesthesia

• The choice between regional and general anesthesia matters less than how sympathetically it is administered relative to the patient's pathophysiological status. 1
• Regional anesthesia with minimal or no sedation offers benefits including reduced hypotension, delirium, cardiorespiratory complications, and decreased opioid requirements. 1
• However, patients with cognitive dysfunction may not tolerate regional anesthesia without heavy sedation, negating the benefits of avoiding general anesthesia's cognitive effects. 1

Spinal Anesthesia Dosing and Technique

Dose Reduction Strategies

• Use 30-50% lower doses than standard adult dosing due to age-related pharmacokinetic and pharmacodynamic alterations. 1, 4
• The dose required to induce anesthesia is lower in elderly patients, with longer onset times increasing risk of myocardial depression and hypotension. 1
• Consider using low-dose intrathecal bupivacaine (<10 mg) to minimize hypotension risk. 5

Individualized Dosing Based on Anatomy

• Measure dural sac cross-sectional area (DSCSA) via ultrasound at L3-4 to calculate modified bupivacaine dose, as this is highly effective for controlling sensory level in geriatric TURP patients. 3
• Patients with decreased DSCSA (spinal canal stenosis) require proportionally reduced doses to avoid excessive cephalad spread. 3
• In a randomized study, ultrasound-guided dosing achieved target T10 blockade versus uncontrolled T3 spread (range T2-T9) with standard 2ml dosing. 3
• The ratio of trunk length to square of abdominal circumference (TL/AC²) correlates with block height; patients with low TL/AC² ratios achieve higher blocks with standard doses. 6

Sequential Combined Spinal-Epidural (CSEA)

• Sequential CSEA (1ml 0.5% hyperbaric bupivacaine intrathecally + 6ml 0.5% isobaric bupivacaine epidurally) provides hemodynamic stability superior to spinal alone while maintaining faster onset than epidural alone. 7
• CSEA allows dose titration and prolonged analgesia, combining advantages of both techniques while minimizing disadvantages. 7

Sedation Management

Minimal to No Sedation Protocol

• Use minimal or no sedation during spinal anesthesia to avoid masking neurological changes from TUR syndrome and to preserve respiratory drive. 1, 5
• If sedation is necessary, use extreme caution as elderly patients are prone to relative overdose causing myocardial depression and impaired blood pressure homeostasis. 1
• Avoid benzodiazepines, opioids as sole adjuncts, antihistamines (including cyclizine), and atropine, as these precipitate delirium. 1

Adjunctive Analgesia

• Add intrathecal fentanyl to prolong analgesia while minimizing respiratory and cognitive depression. 5
• Consider peripheral nerve blockade (femoral nerve or fascia iliaca block) to extend postoperative non-opioid analgesia. 5
• Provide supplemental oxygen throughout the procedure. 5

Hemodynamic Management

Blood Pressure Control

• Avoid simultaneous administration of spinal and general anesthesia, as this causes precipitous blood pressure drops. 5
• Consider early arterial line placement for beat-to-beat blood pressure monitoring given the critical importance of avoiding hypotension. 5
• In the ultrasound-guided dosing study, only 2/30 patients required ephedrine versus 8/30 with standard dosing. 3

Fluid Therapy

• Avoid prolonged preoperative fasting; allow clear fluids up to 2 hours before surgery to prevent dehydration. 4
• Use "restrictive" fluid therapy that replaces losses without causing fluid overload. 1, 4

Intraoperative Monitoring

Standard Monitoring Requirements

• Continuous pulse oximetry, ECG, and non-invasive blood pressure are mandatory. 5
• Core temperature monitoring should be routine. 5
• Implement depth of anesthesia monitoring (BIS or entropy) if general anesthesia is used to prevent relative overdose and facilitate faster emergence. 1, 4
• Strongly consider cerebral oxygen saturation monitoring, as desaturation >15% may indicate ischemia requiring intervention. 5

Positioning and Skin Protection

• Comprehensively pad all probable sites of nerve injury before surgery starts and reassess every 30 minutes throughout the procedure. 4
• Elderly patients are at higher risk of preventable peripheral nerve injuries (ulnar nerve when supine, common peroneal nerve in lithotomy) and lower limb compartment syndrome from prolonged lithotomy positioning. 1
• Reduced skin depth, vascularity, and muscle mass predispose to preventable pressure necrosis over bony prominences, especially heels. 1, 4

End-of-Surgery Checklist

Mandatory Assessment Before Leaving OR

For all patients >75 years, complete this checklist after WHO Surgical Safety Checklist "sign out" before leaving the operating theater: 1, 4

• What is the patient's core temperature?
• What is the patient's hemoglobin concentration?
• Have age-adjusted and renal function-adjusted doses of postoperative analgesia been prescribed?
• Has a postoperative fluid plan been prescribed?
• Can the patient be returned safely to a general care ward?

Postoperative Care Planning

Risk Stratification

• Patients with predicted perioperative mortality >10% should be admitted to level 2 or 3 critical care facility. 1, 4
• Routinely risk-assess elderly patients at end of surgery regarding postoperative care level needed. 1
• Ensure Modified Early Warning Scores and Critical Care Outreach team availability. 1

Pain Management

• Implement multimodal opioid-sparing analgesia including paracetamol as first-line therapy. 1
• Prescribe age-adjusted and renal function-adjusted analgesic doses. 1
• Use morphine cautiously for moderate-severe pain, particularly in patients with poor renal or respiratory function and cognitive impairment. 1
• NSAIDs should be used at lowest doses for shortest duration with proton pump inhibitor protection and routine monitoring for gastric and renal damage. 1

Critical Pitfalls to Avoid

• Do not use standard adult dosing for spinal anesthesia; this leads to excessive cephalad spread, severe hypotension, and increased complications. 1, 3
• Do not heavily sedate patients under spinal anesthesia, as this eliminates the primary advantage of early TUR syndrome detection. 2
• Do not neglect positioning checks during the procedure; reassess padding and pressure points every 30 minutes. 1, 4
• Do not remove functional splints if practicable, and account for kyphoscoliosis, arthritic joints, and fixed flexion deformities when positioning. 1
• Do not use razor for hair removal due to friable elderly skin. 1