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Perioperative Considerations in Care of the Elderly

Perioperative Considerations in Care of the Elderly. Fred Weitz MD Emory University Dept. of Anesthesiology. Realities for the Practicing Anesthesiologist. More than 35 million people in U.S. are > 65 They account for almost half of hospital care days 25-35% surgical cases

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Perioperative Considerations in Care of the Elderly

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  1. Perioperative Considerations in Care of the Elderly Fred Weitz MD Emory University Dept. of Anesthesiology

  2. Realities for the Practicing Anesthesiologist • More than 35 million people in U.S. are > 65 • They account for almost half of hospital care days • 25-35% surgical cases Most anesthesiologists are geriatric anesthesiologists!

  3. All Geriatric Patients are not Created Equal!

  4. People age at different rates:Organ Function

  5. Organ Functional Reserve:Safety Margin of Organ Capacity

  6. Considerations: • Cardiovascular function • Respiratory function • Airway Management • Pharmacokinetics • Body temperature regulation • Postoperative Mental function

  7. CV Changes with Aging • Connective tissue changes • Loss of elasticity • Loss of SA node cells, slowed conduction • Myocyte death without replacement • Decreased response to beta-receptor stimulation

  8. Aging Does Not Diminish: • Intrinsic quality of muscle • Heart does not weaken with age alone • Peripheral vasoconstriction • Enhanced sympathetic nervous system activity at rest • More prone to hypotension with loss of sympathetic tone

  9. Arterial Stiffening • Reflected pressure from “stiffened arteries” increases pressure in aortic root during late systole • Leads to ventricular hypertrophy, impaired diastolic filling

  10. Decreased Venous Compliance • Veins, like arteries, stiffen with age • Stiff veins are less able to “buffer” changes in blood volume • Volume shifts cause exaggerated changes in cardiac filling pressure

  11. Myocyte Death • Cardiac muscle cells die over time • Remaining cells do not divide in adequate numbers in adulthood • Remaining cells hypertrophy to compensate • Another cause of ventricular hypertrophy

  12. Ventricular Contraction • Slows with Aging • Ventricle may not be fully relaxed during beginning of diastolic filling phase • Result: Early diastolic filling is impaired

  13. Elderly End-Diastolic Pressure Young End-DiastolicVolume Dependence on High Filling Pressure Frank-Starling Curve

  14. Consequences of Delayed Relaxation • Late diastolic filling depends on high left atrial pressure and atrial kick • Tachycardia and atrial fibrillation not well tolerated • Narrow range between inadequate filling pressure and fluid overload • Diastolic dysfunction may be the most common cause of heart failure in > 75 y/o

  15. Can the Elderly Heart Increase Output?

  16. Aging and Contractility:Response to Exercise 7 0 Young 6 5 Ejection Fraction (%) Elderly 6 0 5 5 At Rest Maximal Exercise Stratton et al., Circ 1994;89:1648

  17. Decreased Beta-Receptor Responsiveness • Diminished increase in heart rate with stress • Reduced maximum heart rate • Increase their stroke volume • From increase in end diastolic volume

  18. Response to Anesthesia • Anesthetics can: • Remove sympathetic tone • Dramatic when baseline tone is very high • Directly depress heart, vascular smooth muscle • Diminish baroreceptor reflexes

  19. Add to That … • Changes in sympathetic tone from • waxing and waning surgical stimulus • variable depth of anesthesia • Changes in patient’s volume status • Results in LABILE BLOOD PRESSURE !

  20. Summary: Volume Dependence of the Elderly Heart • Elderly heart depends on late filling that in turn depends on left atrial pressure • Elderly heart is also stiff, so the left atrial pressure must be high in order to fill the LV • prone to diastolic dysfunction • poor venous buffering of blood volume makes maintenance of left atrial pressure difficult

  21. Summary: Decreased Response to Beta-Receptor Stimulation • Lessened ability to increase in heart rate • Lessened ability to increase ejection fraction

  22. Aging and Respiratory Function

  23. Lung Volumes:Decreased VC and Increased RV

  24. Pulmonary Changes • Decreased thoracic elasticity • Decreased strength and endurance of respiratory muscles

  25. Decreased Efficiency of Gas Exchange • Breakdown of elastin connections between connective tissue and alveolar tissue • Results in poor tethering of lung tissue to airways and other lung tissue • Airways are NOT held open • Increases: • Shunting • Dead space

  26. Increased Shunt

  27. Explains Effect of Age on paO2

  28. Pre-oxygenation • Takes longer in elderly than in healthy young patients!

  29. Airway Management:Diminished Afferentation • Stimulus threshold for vocal cord closure is increased • Increased risk of aspiration!

  30. Airway Management:Changes with Aging Arthritic Changes: • Decreased cervical spine and neck mobility • Smaller mouth opening • Smaller glottic opening • Smaller endotracheal tube Fragile teeth

  31. Remember… • Airway management may be more difficult • Prone to airway collapse (risk of pneumonia) • Higher work of breathing (risk of hypercarbia) • Lower blood oxygen levels(greater need for supplemental oxygen) • After leaving PACU, hypoxia more likely • from residual drug/CNS effects

  32. Geriatric population is at significantly increased risk of respiratory failure in the postoperative setting!

  33. Pharmacology in the Elderly Patient

  34. Increased Bolus Drug Effect • Decreased protein binding • Higher free, unbound plasma drug levels • Decreased volume of distribution • Slower redistribution of drug • ALL of these INCREASE target organ levels! • Examples: Thiopental, Propofol

  35. Increased Brain Sensitivity • Elderly brain is more sensitive to a given CNS level of a drug • Mechanism ??

  36. Slowed Drug Metabolism: • Clearance decreases as • Liver blood flow decreases • Liver mass decreases • Kidney function decreases • Volume of distribution increases with • Increased body fat • Decreased albumin levels

  37. Bolus Drug Strategy for the Elderly: • GO LOW ! • GO SLOW ! • You can always give more!

  38. Temperature Regulation • Elderly prone to both hypo-, hyperthermia • Lower body metabolism • Decreased ability to change skin blood flow (less able to hold or get rid of heat) • Hypothermia • Shivering increases metabolic demand • Increased risk of myocardial ischemia

  39. The Elderly Brain

  40. CNS Structural Changes • Brain mass decreases with corresponding decreased cerebral blood flow • Decreased receptors • Acetylcholine • Cholinergic neurons in the basal forebrain regulate normal memory • Dopamine • Norepinephrine

  41. Postoperative Cognitive Disorders • Delirium • Mild neurocognitive disorder - POCD • Dementia (rare) • Multiple cognitive deficits • Impairment in activities of daily living

  42. Postoperative Delirium • Most common form of perioperative CNS dysfunction • Acute confusion, decreased alertness, misperception • Patient may show agitation or withdrawal • Twice as common in the elderly • 10-15% of elderly surgical patients • 30-50% if undergoing cardiac or orthopedic surgery • Seen after general, regional and MAC anesthetics • Results in prolonged hospital stay and protracted postoperative care

  43. Postoperative Delirium:Predisposing Factors • Drug withdrawal • Use of benzodiazepines, tricyclic antidepressants • Alcohol abuse • Drug interactions • Anticholinergics, etc. • Pre-existing depression or dementia • Metabolic disturbances

  44. Can Postoperative Delirium be Prevented? • Marcantonio (2001) - Reduced postoperative delirium by 1/3 in hip fracture patients • Minimized benzodiazepines, anticholinergics, antihistamines, meperidine • Maintained BP greater than 2/3 of baseline • Maintained O2 saturation > 90% • Maintained Hct > 30% • Mobilized patients ASAP • Provided appropriate environmental stimulation

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