Preoperative Evaluation and Anesthetic Management of a 72-Year-Old Man with a Cardiac Pacemaker Posted for TURP

I. Overview of the Clinical Scenario

1. Geriatric patient with age-related physiological changes
2. Cardiac pacemaker (CIED - Cardiac Implantable Electronic Device) with risk of electromagnetic interference (EMI)
3. TURP - a procedure with unique risks: TURP syndrome, lithotomy position, bleeding, and historically significant use of monopolar electrocautery

II. Preoperative Evaluation

A. History and Clinical Assessment

• Indication for pacemaker (sick sinus syndrome, complete heart block, bradyarrhythmia, etc.)
• Type of device: single-chamber, dual-chamber, biventricular (CRT), or ICD-pacemaker combination
• Manufacturer and model (the patient should carry a device ID card)
• Date of last device interrogation and battery status
• Whether the patient is pacemaker-dependent - this is the single most critical piece of information. A pacemaker-dependent patient has no adequate escape rhythm and will develop hemodynamic collapse if pacing is inhibited
• Rate-response (RRM) sensor type and whether it is enabled (activity sensors, minute ventilation sensors)
• Magnet response of the specific device

• Underlying cardiac disease (cardiomyopathy, ischemic heart disease, valvular disease, heart failure)
• NYHA functional class and exercise tolerance (in METs)
• Recent ECG, echocardiogram (assess LV ejection fraction), and any stress tests
• Current medications - especially anticoagulants, antiplatelets, beta-blockers, antiarrhythmics

• BPH severity, previous urologic procedures, recent UTI
• Comorbidities: diabetes, renal impairment (important for fluid management and TURP syndrome risk), COPD, hypertension
• Prior anesthetic history
• Bleeding history; laboratory workup including CBC, electrolytes, renal function, coagulation profile, blood glucose

B. Preoperative Device Interrogation

• Identification of the device type and current programmed settings
• Battery life status
• Pacing threshold and sensing parameters
• Rate-response mode status
• Magnet response function
• For ICD-pacemakers: whether the antitachycardia/defibrillation function is active

• Recent interrogation report
• Guidance on whether to reprogram or use a magnet intraoperatively
• Postoperative reprogramming plan

C. Risk Stratification

• Apply the ACC/AHA stepwise algorithm for noncardiac surgery
• Assess RCRI (Revised Cardiac Risk Index): TURP is intermediate-risk surgery
• Assess functional capacity: if the patient cannot walk on flat ground without symptoms, further cardiac workup may be needed
• Assess for active cardiac conditions (unstable angina, decompensated heart failure, significant arrhythmias, severe valvular disease) - these must be addressed before elective TURP

D. Airway and Respiratory Assessment

• Full airway assessment (Mallampati, mouth opening, neck mobility)
• Baseline SpO2 and respiratory function, as lithotomy position worsens FRC and pulmonary compliance

E. Preoperative Optimization

• Ensure optimal medical management of heart failure, hypertension, diabetes
• Review anticoagulation: if the patient is on warfarin or direct oral anticoagulants, plan bridging or cessation per the surgeon and cardiologist's guidance
• Correct electrolyte abnormalities, especially hyponatremia or hypokalemia (these affect pacemaker threshold and TURP syndrome risk)
• NBM (nothing by mouth) as per standard guidelines (6h solid food, 2h clear fluids)

III. Anesthetic Management

A. Electromagnetic Interference (EMI) - The Central Pacemaker Concern

• Oversensing: EMI signals may be interpreted by the pacemaker as intrinsic cardiac activity, causing pacemaker inhibition (dangerous in pacemaker-dependent patients)
• Inappropriate shocks: If the patient has a combined ICD-pacemaker, EMI may be misinterpreted as a malignant tachyarrhythmia, triggering an inappropriate defibrillation shock

B. Choice of Anesthetic Technique

• Covers the prostate and bladder neck (T11-L2 afferents)
• Higher levels (above T10) may mask symptoms of bladder/capsule perforation (abdominal or shoulder pain, nausea)

1. Allows awake monitoring for TURP syndrome symptoms
2. Avoids airway instrumentation and hemodynamic fluctuations of general anesthesia
3. Lower 30-day mortality shown in large ACS-NSQIP database analysis
4. Avoids volatile anesthetic effects on cardiac output
5. Pacemaker EMI from intubation/ventilation (minute ventilation sensors) is avoided

• Spinal-induced sympathectomy may cause hypotension - particularly dangerous in a pacemaker patient who may already have cardiac compromise
• If the patient is on anticoagulants, neuraxial block may be contraindicated - in that case, general anesthesia is used

• Hyperbaric bupivacaine 0.5% (10-12.5 mg) with or without a small dose of fentanyl (10-25 mcg) for quality enhancement and reduced bupivacaine dose

C. Intraoperative Monitoring

• Continuous ECG with pacemaker function monitoring (ensure pacemaker spikes are visible)
• Pulse oximetry (important for pacemaker-dependent patients as it provides a continuous pulse check independent of ECG)
• Non-invasive blood pressure (frequent cycling)
• Peripheral pulse monitoring via pulse oximeter plethysmography - separate from ECG - to detect pacemaker inhibition even if pacemaker spikes are present on ECG
• Temperature monitoring (hypothermia lowers pacemaker thresholds)
• Fluid balance monitoring (critical for TURP syndrome detection)

• External pacemaker/defibrillator with pads applied before surgery
• Temporary pacing capability
• Magnet (even if not planned for use, in case of unexpected EMI)

D. Positioning

• Increased cardiac preload (venous return from legs)
• Cephalad diaphragm shift, decreased FRC, decreased lung compliance
• Risk of nerve injuries (common peroneal, sciatic, femoral)
• These hemodynamic shifts must be anticipated, especially in a patient with potentially compromised cardiac function

E. Fluid Management

• TURP (especially M-TURP with hypotonic irrigants like glycine) carries the risk of TURP syndrome
• The syndrome affects 2-15% of M-TURP procedures
• Monitor fluid balance by comparing instilled vs. returned irrigation volumes
• If >1000 mL has been absorbed in a male patient, halt surgery and check sodium and neurological status
• Surgery must be terminated if >2000 mL absorbed (hypotonic irrigant) or >2500 mL (saline irrigant with B-TURP)
• Volume overload from irrigation fluid absorption is particularly dangerous in a pacemaker patient who may have impaired cardiac reserve

F. Management of TURP Syndrome

1. Stop irrigation immediately
2. Loop diuretic (furosemide) if volume overloaded
3. For severe symptomatic hyponatremia (Na+ <120 mEq/L with neurological symptoms): hypertonic saline (3%) - raise Na+ by no more than 8-10 mEq/L per 24h to avoid osmotic demyelination syndrome
4. Serum Na+, osmolality, and urine output monitoring
5. Magnesium sulfate for seizures (also counteracts the excitatory effects of glycine on NMDA receptors)
6. Hemodialysis if osmolality is normal or near-normal but Na+ is severely low

G. Postoperative Care

• Monitor cardiac rhythm continuously in the recovery room - pacemaker inhibition events may not manifest until the postoperative period
• Device reprogramming must be done immediately postoperatively to restore original settings (rate-response, ICD therapy if disabled)
• Monitor for TURP syndrome signs for up to 24 hours
• Careful fluid balance management
• Adequate analgesia to avoid sympathetic stimulation, which can confound pacemaker sensing
• Coordinate with electrophysiology for formal device re-interrogation before discharge

IV. Summary Table

• Miller's Anesthesia, 10th ed. - Chapters 28 (CIEDs) and 55 (TURP anesthesia)
• Morgan & Mikhail's Clinical Anesthesiology, 7th ed. - Chapter on cardiac arrhythmias and device management
• HRS/ASA Expert Consensus Statement on perioperative management of CIEDs (referenced throughout Miller's 10th ed.)