How does a high Clinical Frailty Scale (CFS) score impact the outcome of general anesthesia and postextubation care in surgical patients?

Clinical Frailty Scale and Perioperative Outcomes

High Clinical Frailty Scale scores independently predict increased perioperative morbidity, mortality, and postoperative complications in surgical patients undergoing general anesthesia, requiring mandatory preoperative frailty assessment by senior geriatricians and anesthetists, with subsequent modifications to anesthetic dosing, depth monitoring, and postoperative care level.

Frailty as an Independent Risk Factor

Frailty represents a state of decreased physiologic reserve that fundamentally alters surgical risk independent of age or comorbidities. 1

• Age-related physiological decline, multi-morbidity, and frailty are independently associated with increased perioperative risk 1
• Frail patients experience more than 2-fold increased risk of morbidity, mortality, and development of new patient-reported disability after major surgery 2
• Approximately 30-50% of older patients presenting for major surgery are living with frailty 2
• The prevalence of frailty increases dramatically with age, reaching 26% in those aged above 85 years 3

Mandatory Preoperative Assessment Requirements

Pre-operative assessment of higher-risk elderly patients must involve both a senior geriatrician and a senior anesthetist with specific subspecialty training in geriatrics. 1

• Structured multifactorial assessment should identify physical disability, malnutrition, cognitive dysfunction, and mental health diagnoses 2
• The Clinical Frailty Scale appears to be the most feasible frailty instrument for use before surgery, though predictive accuracy does not differ significantly between validated instruments (Fried Phenotype, Edmonton Frail Scale, Frailty Index) 2
• Pre-operative assessment is more resource-efficient when targeted towards patients with higher perioperative risk 1

Specific Anesthetic Modifications Required

Dosing Adjustments

All induction doses must be reduced by 30-50% from standard adult dosing in frail elderly patients. 4, 5, 6

• Age-related alterations in pharmacokinetics and pharmacodynamics necessitate this reduction 4
• Elderly patients have longer onset times, increasing risk of myocardial depression and hypotension 4
• Standard adult dosing leads to relative overdose and preventable complications 4

Depth of Anesthesia Monitoring

Depth of anesthesia monitoring using BIS or processed EEG is strongly recommended for patients over 60 years at risk of postoperative delirium. 1, 4

• Titrating anesthesia to avoid burst suppression and extremely low BIS values reduces postoperative delirium risk 1
• A recent study targeting lighter anesthesia (BIS 50 versus BIS 35) found significant reduction in postoperative delirium in older surgical patients 1
• Frail patients have high incidence of postoperative cognitive dysfunction and delirium 1
• Processed EEG-guided care facilitates rapid emergence and recovery 1

Postextubation Considerations

Immediate Extubation Criteria

Complete an end-of-surgery checklist before leaving the operating theater for all patients >75 years undergoing major/emergency surgery. 4

The checklist must include:

• Core temperature verification 4
• Hemoglobin concentration 4
• Age-adjusted and renal function-adjusted doses of postoperative analgesia 4
• Postoperative fluid plan 4
• Confirmation of safe return destination (general ward versus higher level care) 4

Neuromuscular Recovery

Use quantitative neuromuscular monitoring to confirm train-of-four ratio >0.9 before extubation. 5

• Do not extubate without confirming adequate neuromuscular recovery using quantitative monitoring 4
• Sugammadex is preferred over neostigmine for complete and rapid reversal 5

Postoperative Care Level Determination

Patients with predicted perioperative mortality >10% must be admitted to level 2 or 3 critical care. 4, 6

• Routinely risk-assess elderly patients at end of surgery regarding postoperative care level needed 4
• Do not ration care based on age alone; elderly patients should have equal access to critical care when clinically indicated 4

Specific Complications in Frail Patients

Postoperative Cognitive Disorders

Frail patients are at substantially higher risk of postoperative delirium (POD) and postoperative cognitive decline (POCD). 1

Risk factors include:

• Very old age 1
• Frailty status 1
• Pre-existing cognitive impairment 1
• Cardio-/cerebrovascular disease 1
• Multimorbidity/polypharmacy 1

Early recognition must be communicated throughout the multidisciplinary care team to facilitate multimodal interventions 1

Cardiorespiratory Complications

Age-related physiological changes render frail patients effectively "beta-blocked" with limited ability to respond to stress. 1

• Reduced cardiac responsiveness limits ability to increase cardiac output and respond to fluid losses 1
• Baroreceptor dysfunction and reduced responsiveness to angiotensin II further limit response to hypovolemia 1
• Cardiopulmonary changes contribute to decline in oxygen uptake and delivery, rendering patients at greater risk of perioperative myocardial and cerebral ischemia 1

Pre-optimization Strategies

Pre-optimization should focus on reducing specific postoperative complications rather than delaying surgery. 1

Key targets include:

• Ischemia prevention: Reduce oxygen uptake (analgesia, thermoregulation, antibiotics) and improve oxygen delivery (oxygen, fluids, medication review, avoidance of hypotension and severe anaemia) 1
• Malnutrition correction: Iron, vitamin B12, and folate supplementation provided at least 28 days before elective surgery reduces postoperative morbidity and mortality 1
• Avoid prolonged fasting: Allow clear fluids up to 2 hours before surgery to prevent dehydration 4

Critical Pitfalls to Avoid

• Never use standard adult dosing for any anesthetic agent in frail elderly patients 4
• Never neglect positioning checks during long cases; reassess every 30 minutes to prevent pressure necrosis over bony prominences 4
• Never delay emergency surgery for optimization; pre-operative delay before hip fracture surgery and emergency laparotomy is associated with poorer postoperative outcome 1
• Never extubate without quantitative neuromuscular monitoring confirmation 4

Regional Anesthesia Considerations

Regional anesthesia with minimal/no sedation may reduce hypotension, delirium, cardiorespiratory complications, and opioid requirements in frail patients. 4, 6

• The technique matters less than how sympathetically it is administered relative to the patient's pathophysiological status 4
• Spinal anesthesia doses must still be reduced by 30-50% in elderly frail patients 6