What are the anaesthetic implications for an older adult patient with Ischaemic Heart Disease (IHD), hypertension, hyperlipidaemia, diabetes, and a history of smoking, undergoing surgery?

Anaesthetic Management of Older Adults with Ischaemic Heart Disease

Patients with IHD undergoing non-cardiac surgery require meticulous perioperative haemodynamic control to prevent myocardial ischaemia through two critical mechanisms: maintaining myocardial oxygen supply-demand balance and preventing acute coronary syndromes from plaque rupture triggered by perioperative stress. 1

Pre-operative Risk Assessment

Cardiovascular Evaluation

• Obtain a current 12-lead ECG to compare with prior tracings, evaluating for new ischaemic changes, tachycardia, arrhythmias, or prolonged QTc interval (>440 ms) 1, 2
• Calculate the Lee (Revised Cardiac Risk Index) score; if ≥2 with functional capacity <4 METs, refer to cardiology for stress testing or imaging before major surgery 1, 2
• Assess functional capacity by determining if the patient can climb two flights of stairs or walk four blocks without symptoms 2
• Review echocardiogram results if available, and consider BNP/pro-BNP measurement if cardiac ischaemia is suspected 1

Diabetes-Specific Cardiac Assessment

Given the patient's diabetes, screen for cardiac autonomic neuropathy (CAN) which dramatically increases perioperative haemodynamic instability risk 1, 3:

• Check for symptoms: permanent tachycardia, orthostatic/post-prandial hypotension, severe hypoglycaemia without warning 1, 3
• Measure orthostatic vital signs (lying and standing blood pressure/heart rate) 2, 3
• Perform respiratory heart rate variability testing if CAN suspected, as preoperative decrease in respiratory sinus arrhythmia predicts perioperative haemodynamic instability 1, 3
• Patients with CAN have increased vasopressor requirements and risk of silent myocardial infarction 3

Medication Review

• Continue beta-blockers (if already prescribed) through the morning of surgery with a sip of water, as abrupt discontinuation risks severe angina exacerbation, myocardial infarction, and ventricular arrhythmias 4
• Continue ACE inhibitors/ARBs perioperatively 5
• Review for CYP2D6 inhibitors (SSRIs, antipsychotics, antiarrhythmics) that increase metoprolol levels and reduce cardioselectivity 4
• Identify drugs causing orthostatic hypotension that should be avoided if CAN detected 3

Intra-operative Management

Haemodynamic Goals

The primary objective is preventing myocardial ischaemia by avoiding haemodynamic fluctuations that create supply-demand mismatch 1:

• Maintain systolic blood pressure within 10% of baseline to reduce risk of postoperative delirium and cognitive decline in elderly patients 1
• Maintain SpO₂ >95% 1
• Avoid tachycardia as it increases myocardial oxygen demand and reduces diastolic coronary perfusion time 1
• Prevent hypotension which directly reduces coronary perfusion, especially critical in patients with flow-limiting stenoses 1

Anaesthetic Technique Selection

Regional anaesthesia (spinal/epidural) is preferred over general anaesthesia when feasible 2, 5:

• Reduces sympathetic hyperactivity, particularly beneficial in diabetic patients with metabolic syndrome 1, 2
• Decreases perioperative hypertension by reducing sympathetic tone 1
• Allows better postoperative pain control and early mobilization 2, 5
• Enables patient cooperation with physiotherapy, especially important with concurrent COPD 5

Monitoring Requirements

• Use depth-of-anaesthesia monitoring (BIS/entropy) to prevent relative overdose, as elderly patients require lower anaesthetic doses and are prone to prolonged hypotension from excessive depth 1
• Avoid "triple low" (low BIS, hypotension, low inspired agent) which increases mortality and hospital stay 1
• Use peripheral nerve stimulation when administering neuromuscular blockers, as pharmacokinetic/pharmacodynamic changes cause unpredictably prolonged blockade in elderly patients 1
• Continuous ECG monitoring for ischaemic changes, arrhythmias, and heart rate control 1
• Consider invasive arterial monitoring for major surgery to enable beat-to-beat blood pressure management 1

Anaesthetic Agent Considerations

• Adjust doses for age: elderly patients require significantly lower doses of induction and maintenance agents 1
• Use age-adjusted MAC values or Lerou nomogram if depth monitors unavailable 1
• Volatile anaesthetics may provide cardioprotection through preconditioning mechanisms, though clinical translation remains debated 6
• Avoid abrupt beta-blocker withdrawal perioperatively, as chronically administered beta-blockade should not be routinely discontinued before major surgery despite impaired reflex adrenergic response 4

Fluid Management

• Use restrictive fluid therapy that replaces pre- and intra-operative losses without causing hypovolaemia, as elderly patients have reduced homeostatic compensation for fluid boluses 1
• Avoid prolonged preoperative fasting; allow clear fluids up to 2 hours before surgery 1
• Monitor for fluid overload which can precipitate heart failure 1

Positioning and Nerve Protection

• Comprehensively pad probable nerve injury sites before surgery and reassess every 30 minutes, as elderly patients have higher risk of preventable peripheral nerve injuries during prolonged procedures 1
• Account for kyphoscoliosis, arthritic joints, and fixed flexion deformities when positioning 1

Post-operative Management

Cardiovascular Monitoring

• Continue close haemodynamic monitoring in recovery, as perioperative myocardial ischaemia often occurs postoperatively due to stress response, pain, and fluid shifts 1
• Monitor for silent myocardial infarction, particularly in diabetic patients with CAN who may not experience typical anginal symptoms 3
• Obtain serial ECGs and cardiac biomarkers if clinically indicated 1

Pain Management

• Provide multimodal analgesia to reduce sympathetic stress response and myocardial oxygen demand 1, 5
• Consider epidural analgesia continuation for major surgery 1

Complication Prevention

• Early mobilization to reduce thromboembolic risk and pulmonary complications 5
• Maintain normothermia to reduce oxygen consumption 1
• Optimize oxygenation to ensure adequate myocardial oxygen delivery 1

Critical Pitfalls to Avoid

• Never abruptly discontinue beta-blockers perioperatively in patients with coronary artery disease, as this precipitates severe complications 4
• Do not delay urgent surgery for "optimization" of chronic conditions beyond 48 hours, as delay increases mortality without improving outcomes 5
• Avoid excessive anaesthetic depth in elderly patients; use monitoring to guide dosing 1
• Do not ignore signs of CAN in diabetic patients, as this dramatically increases haemodynamic instability risk 1, 3
• Avoid hypotension and tachycardia which are the primary triggers of perioperative myocardial ischaemia 1
• Do not use epinephrine-containing local anaesthetics without careful consideration, though 10ml of 2% lidocaine with 1:100,000 epinephrine appears safe in stable IHD patients 7