What are the anesthetic considerations for elderly patients undergoing surgery?

Anesthetic Considerations for the Elderly Patient

Elderly patients require reduced anesthetic doses (30-50% lower than standard adult dosing), depth of anesthesia monitoring, meticulous positioning and skin protection, and a structured end-of-surgery checklist to reduce preventable morbidity and mortality. 1, 2

Pharmacological Adjustments

Induction Agents

• Reduce all induction doses by 30-50% from standard adult dosing due to age-related alterations in pharmacokinetics and pharmacodynamics 2, 3
• Elderly patients require lower doses to achieve anesthesia and have longer onset times, increasing risk of myocardial depression and hypotension 1
• Opioid requirements are reduced by approximately 50% in elderly patients 3

Depth of Anesthesia Monitoring

• Depth of anesthesia monitoring (BIS or entropy) is strongly recommended to prevent relative overdose and facilitate faster emergence 1, 2, 3
• This is critical because elderly patients are highly sensitive to overdose, resulting in myocardial depression, impaired blood pressure homeostasis, and delayed recovery 1

Neuromuscular Blocking Agents

• Expect delayed onset of action and prolonged duration of neuromuscular blockade 1, 3
• Quantitative neuromuscular monitoring is mandatory to ensure train-of-four ratio >0.9 before extubation 2, 3
• Sugammadex is preferred over neostigmine for complete and rapid reversal 2

Choice of Anesthetic Technique

Regional vs. General Anesthesia

• The technique matters less than how sympathetically it is administered relative to the patient's pathophysiological status 1
• Regional anesthesia with minimal/no sedation may reduce hypotension, delirium, cardiorespiratory complications, and opioid requirements 1
• However, patients with cognitive dysfunction may not tolerate regional anesthesia without heavy sedation, negating benefits 1
• No reliable difference exists in 30-day mortality or length of stay between regional and general anesthesia 1

Specific Agent Considerations

• Short-acting agents (remifentanil, desflurane, sevoflurane) facilitate rapid emergence and are preferred 2, 4, 5
• Desflurane should not be used as sole agent for induction in patients with coronary artery disease due to increases in heart rate and blood pressure 6
• When desflurane is used in cardiac patients, it must be combined with intravenous opioids and hypnotics for induction 6

Intraoperative Positioning and Skin Protection

Peripheral Nerve Injury Prevention

• Comprehensively pad all probable sites of nerve injury before surgery starts and reassess every 30 minutes throughout the procedure 1
• High-risk sites include: ulnar nerve (supine), common peroneal nerve (lithotomy), dependent radial nerve (lateral position), and brachial plexus (prolonged lateral neck flexion) 1
• Account for kyphoscoliosis, arthritic joints, and fixed flexion deformities when positioning 1

Pressure Necrosis Prevention

• Reduced skin depth, vascularity, and muscle mass predispose elderly patients to preventable pressure necrosis over bony prominences (especially heels) 1
• Prolonged hypotension contributes to pressure sore development, which delays discharge and increases infection risk 1
• Friable skin requires careful handling during transfers and when removing adhesive items (diathermy pads, tape, dressings) 1
• Avoid razors for hair removal; use clippers instead 1
• Exercise caution with contact warming devices due to increased thermal injury risk 1

Fluid and Hemodynamic Management

Fluid Therapy

• Avoid prolonged preoperative fasting; allow clear fluids up to 2 hours before surgery to prevent dehydration 1
• High-risk patients undergoing major surgery benefit from "restrictive" fluid therapy that replaces losses without causing fluid overload 1
• Reduced homeostatic compensation means elderly patients tolerate neither hypovolemia nor fluid boluses well 1

Blood Transfusion

• Preoperative and postoperative anemia are common and associated with myocardial ischemia, falls, and poor wound healing 1
• Observational data suggest patients >65 years have lower mortality with preoperative hematocrit 30-36% and operative blood loss <500 mL 1

End-of-Surgery Checklist

For all patients >75 years undergoing major/emergency surgery, complete this checklist before leaving the operating theater: 1

• 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

Level of Care Determination

• Patients with predicted perioperative mortality >10% should be admitted to level 2 or 3 critical care 1
• Routinely risk-assess elderly patients at end of surgery regarding postoperative care level needed 1
• Discharge to critical care if this will significantly reduce morbidity/mortality or if organ support is required 1

Postoperative Cognitive Dysfunction Prevention

• Identify high-risk patients preoperatively: very old, frail, cognitively impaired, or with cardiovascular/cerebrovascular disease 1
• Communicate risk throughout the multidisciplinary team to facilitate multimodal interventions 1
• Postoperative delirium is common but underdiagnosed and delays rehabilitation 1

Pain Management

• Implement multimodal opioid-sparing analgesia including local anesthetic infiltration 2, 4, 7
• Intravenous acetaminophen achieves rapid peak plasma concentration (<15 minutes) and provides analgesia for up to 4 hours 4
• Prescribe age-adjusted and renal function-adjusted analgesic doses 1
• Pain is common but underappreciated in elderly surgical patients, particularly those with cognitive impairment 1

Common Pitfalls to Avoid

• Do not use standard adult dosing for any anesthetic agent; this leads to relative overdose 1, 2, 3
• Do not extubate without confirming adequate neuromuscular recovery using quantitative monitoring 2, 3
• Do not neglect positioning checks during long cases; reassess every 30 minutes 1
• Do not ration care based on age alone; elderly patients should have equal access to critical care when clinically indicated 1
• Do not assume capacity is absent; elderly patients should be presumed to have decision-making capacity unless clearly demonstrated otherwise 1