Anaesthetic Management of a 60-Year-Old Male with Irregular Hypertension and Atrial Fibrillation Posted for Herniorrhaphy

Introduction

1. Preoperative Assessment

History

• Duration and severity of hypertension, drug compliance, and response to therapy
• Symptoms of end-organ damage: chest pain (IHD), exertional dyspnea (heart failure), visual disturbances (hypertensive retinopathy), neurological symptoms (stroke/TIA), claudication (PVD), reduced urine output (CKD)
• AF: onset, paroxysmal vs. persistent vs. permanent; rate vs. rhythm control strategy; palpitations, syncope
• Anticoagulation status: warfarin / DOAC therapy for stroke prevention
• Current medications: antihypertensives, rate-control agents, anticoagulants

Examination

• BP both arms (sitting and standing); pulse - irregularly irregular with pulse deficit
• Signs of LV hypertrophy, heart failure (JVP, S3, pedal edema, basal crepitations)
• Bruits (carotid, renal), thyroid (exclude hyperthyroidism as AF cause)
• Mallampati grading, neck movements, mouth opening (airway assessment)

Investigations

• ECG: absent P waves, irregular RR intervals (AF); LVH voltage criteria, ST-T changes (ischemia)
• Chest X-ray: cardiomegaly, pulmonary congestion
• 2D Echocardiogram: LV function (EF), wall motion abnormalities, valvular disease, LA enlargement
• Labs: CBC, renal function (creatinine, BUN), serum electrolytes (K+, Mg2+ - diuretic effects), blood glucose, lipids, LFTs, coagulation profile (INR if on warfarin)
• Thyroid function (if clinically suspected)

2. Risk Stratification

Goldman Cardiac Risk Index / Revised Cardiac Risk Index (RCRI)

CHA₂DS₂-VASc Score (for AF stroke risk)

3. Preoperative Optimization

Hypertension

• Target BP: <130/80 mmHg ideally; elective surgery is generally safe if BP <180/110 mmHg
• Delay surgery if systolic >180 mmHg or diastolic >110 mmHg and optimize antihypertensives
• Continue all antihypertensives on the morning of surgery except:
  • ACE inhibitors (ACEIs) and ARBs: withhold 24 hours before surgery to prevent severe intraoperative hypotension on induction (though decision should be individualized)
  • Resume postoperatively once hemodynamically stable (failure to restart is itself associated with adverse outcomes)
• Beta-blockers: must NOT be stopped - abrupt withdrawal causes rebound hypertension and tachycardia (Morgan & Mikhail, 7e)

Atrial Fibrillation

• Rate control is the primary perioperative goal: target ventricular rate 60-100 bpm at rest
  • Patients with ventricular rate >100 bpm require rate control before any elective surgery
  • Patients with AF and slow ventricular rate without rate-controlling agents may have sick sinus syndrome - evaluate carefully (Miller's Anesthesia, 10e)
• Rate control agents: beta-blockers, calcium channel blockers (diltiazem, verapamil), or digoxin
• Patients on anticoagulation (warfarin/DOAC):
  • For elective herniorrhaphy (low bleeding risk), warfarin/DOAC is interrupted 2-5 days preoperatively
  • Bridging anticoagulation is NOT routinely needed - a landmark RCT (BRIDGE trial, N=1884 AF patients) showed no difference in arterial thromboembolism rates, but significantly higher major bleeding in the bridging group. Interrupting anticoagulation in AF patients is safe for elective non-cardiac surgery (Barash Clinical Anesthesia, 9e)
  • Check INR if on warfarin; target INR <1.5 for regional anesthesia

4. Choice of Anaesthesia

• Avoids airway manipulation, attenuates stress response
• Benefits: excellent muscle relaxation, lower blood loss, reduced DVT risk, postoperative analgesia
• Concerns: sympathetic blockade → hypotension, especially pronounced in hypertensives (altered autoregulation) and in those with reduced cardiac reserve from AF
• Preload with crystalloid before spinal block; vasopressors (phenylephrine, ephedrine) ready
• Contraindicated if patient is fully anticoagulated (check INR/anti-Xa levels)

• Hypertensives have accentuated hypotension at induction, followed by exaggerated hypertension at laryngoscopy/intubation - blunt with lidocaine, fentanyl, or beta-blocker (esmolol)
• Avoid thiopental (marked hypotension); prefer propofol carefully titrated or etomidate
• Maintain depth with volatile agents (isoflurane/sevoflurane); avoid tachycardia
• Carefully monitor depth: light anesthesia → hypertensive response; deep → hypotension
• Regional block (ilioinguinal/iliohypogastric nerve block) as adjunct reduces GA requirements

5. Intraoperative Monitoring

• Standard: ECG (5-lead preferred for ST monitoring), pulse oximetry, non-invasive BP, capnography, temperature
• Enhanced: Invasive arterial line (intra-arterial BP monitoring) if BP poorly controlled or severe end-organ damage - gives beat-to-beat monitoring, especially important given irregular pulse from AF makes NIBP less reliable
• Urine output via urinary catheter for major fluid shifts
• Central venous access if significant cardiac dysfunction

6. Intraoperative Anaesthetic Goals

• The irregularly irregular rhythm of AF makes beat-to-beat BP assessment unreliable by NIBP - intra-arterial line is advantageous
• If new-onset rapid AF occurs intraoperatively: first correct reversible causes (hypoxia, hypovolemia, electrolyte imbalance, hypothermia), then rate control with IV esmolol or diltiazem; cardioversion only if hemodynamically compromised

7. Fluid Management

• Hypertensive patients with LVH have reduced diastolic compliance - avoid both aggressive fluid loading (flash pulmonary edema) and hypovolemia (hypotension)
• Use balanced crystalloid (Ringer's lactate or PlasmaLyte); avoid large NS volumes (hyperchloremic acidosis)
• Monitor closely; maintain euvolemia

8. Postoperative Management

• BP monitoring: continue antihypertensives as early as possible postoperatively
• Restart anticoagulation: resume DOAC/warfarin as soon as hemostasis is secured (usually 24-48 hours post-herniorrhaphy); failure to restart is independently associated with adverse outcomes
• Multimodal analgesia: paracetamol + NSAIDs (caution in hypertensives/CKD) + local infiltration/nerve block; avoid undertreatment (pain raises BP and heart rate)
• DVT prophylaxis: LMWH + compression stockings; AF already confers thromboembolic risk
• Monitor for complications:
  • Postoperative AF: treat with rate control (IV esmolol/diltiazem); if persists >24 hrs and patient stable, rhythm control with amiodarone may be considered
  • Myocardial injury (MINS): 12-lead ECG + troponin if suspected
  • Hypertensive crisis: IV labetalol, hydralazine, or GTN infusion

9. Anaesthetic Drug Considerations

10. Summary of Key Principles

1. Optimize BP preoperatively - proceed only if BP <180/110 mmHg; continue antihypertensives (withhold ACEi/ARB 24 hours before)
2. Control ventricular rate - AF with HR >100 bpm is a contraindication to elective surgery until controlled
3. CHA₂DS₂-VASc score ≥2 - manage anticoagulation carefully; bridging is NOT required for herniorrhaphy; restart anticoagulation promptly post-op
4. Spinal anaesthesia is preferred for herniorrhaphy but requires hemostatic safety and careful management of hypotension
5. Intraoperative hemodynamic goals: avoid tachycardia, prevent large BP swings, maintain euvolemia, ensure adequate analgesia
6. Exaggerated hemodynamic responses - hypertensives show accentuated hypotension at induction and exaggerated hypertension at laryngoscopy/intubation (Morgan & Mikhail, 7e)
7. Postoperative: restart antihypertensives and anticoagulation early, multimodal analgesia, monitor for AF, cardiac injury, and hypertensive episodes

• Morgan & Mikhail's Clinical Anesthesiology, 7e - Chapters on Hypertension and Cardiac Disease
• Miller's Anesthesia, 10e - Chapters on Hypertension and Atrial Fibrillation in Perioperative Care
• Barash, Cullen & Stoelting's Clinical Anesthesia, 9e - Perioperative Anticoagulation and Cardiac Management
• Sabiston Textbook of Surgery, 10e - Postoperative Arrhythmias