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People over 65 years of age are 3.5 times more likely to have surgery. Aging results in a progressive decline in the functional reserve of all organs; the rate at which function diminishes is highly variable between individuals.

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  • Cardiovascular
    • Decreased arterial elasticity:
      • Increased afterload
      • Left ventricular hypertrophy
      • Increased systolic blood pressure, mean arterial pressure, and pulse pressure
    • Autonomic imbalance:
      • Increased vagal tone
      • Decreased sensitivity of adrenergic receptors
      • Decreased baroreceptor reflex
    • Fibrosis of the conducting system and loss of sinoatrial node cells
    • Sclerosis/calcification of valves
    • High incidence of diastolic dysfunction
  • Respiratory
    • Decreased lung tissue elasticity (due to reorganization of collagen and elastin):
      • Early collapse of small airways and overdistension of alveoli (V/Q mismatch)
      • Increased residual volume (total lung capacity unchanged)
      • Increased closing capacity
      • Decreased arterial oxygen tension
      • Loss of alveolar surface area (increased anatomic and physiologic dead space)
    • Increased V/Q mismatch
    • Increased chest wall rigidity leading to increased work of breathing
    • Blunted response to hypercapnia, hypoxia, and mechanical stress
    • Decreased protective reflexes (coughing and swallowing) increasing the risk for aspiration
    • Increased pulmonary vascular resistance and pulmonary arterial pressure
    • Blunted hypoxic pulmonary vasoconstrictive response
  • Renal
    • Decreased renal mass:
      • Mostly renal cortex secondary to decreased functioning glomeruli
      • Progressive decline in creatinine clearance
      • Increased risk of perioperative acute renal failure
    • Decreased renal blood flow:
      • Decreases 10% every decade of aging
      • Serum creatinine unchanged due to loss of muscle mass
    • Decreased tubular function:
      • Altered sodium balance, urine concentrating ability, and drug excretion
      • Increased risk for dehydration and electrolyte abnormalities
    • Decreased renin–aldosterone system resulting in impaired potassium excretion
  • Neurologic
    • Decreased brain mass, particularly the cerebral cortex (frontal lobes)
    • Cerebral blood flow decreases 10–20%, although autoregulation stays intact
    • Decreased neurotransmitter synthesis: GABA, serotonin, dopamine, norepinephrine, and acetylcholine system
    • Variable degrees of cognitive function decline, especially short-term memory
    • Decreased general anesthesia (MAC) and local anesthetic requirements
  • Gastrointestinal
    • Decreased liver function secondary to reduced liver mass and hepatic blood flow:
      • Reduced biotransformation
      • Decreased albumin production
      • Decreased plasma cholinesterase
    • Delayed gastric emptying
    • Increased gastric pH
  • Musculoskeletal
    • Reduced muscle mass; atrophic skin; frail veins
    • Increased body fat; total body water decreases
    • Arthritis can affect various joints that can complicate positioning
    • Degenerative changes of the cervical spine; intubation potentially more difficult
  • Endocrine/metabolic
    • Atrophy of endocrine glands leading to impaired hormone function:
      • Insulin, thyroxine, growth hormone, testosterone
    • Blunted neuroendocrine stress response
    • Decreased heat production and alteration in hypothalamic temperature-regulating center increases risk of hypothermia
  • Age-related pharmacologic effects
    • Increased body fat and decreased total body water:
      • Higher plasma concentration of water-soluble drugs
      • Lower plasma concentration of fat-soluble drugs
    • Reduced clearance secondary to decreased hepatic and renal function
    • Altered protein binding:
      • Reduced albumin affects binding of acidic drugs (opioids, barbiturates, benzodiazepines)
      • Increased α1-acid glycoprotein affects binding of basic drugs (local anesthetics)
    • Pharmacodynamic changes:
      • Drug effects may be intensified due to decreased number of available receptors
      • Reduced anesthetic requirement (or MAC)

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  • Perform a thorough history and physical examination and determine appropriate preoperative testing (based on clinical correlate)
  • Assess optimization of preexisting conditions such as CAD, ...

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