Anesthesia for the Geriatric Patient

1. Anesthesia for the Geriatric Patient Jonathan Weed, MD

2. All of the following are associated with the age-related changes in the kidney EXCEPT? • Decreased serum creatine concentration • Decreased number of glomeruli • Renal perfusion shifted to the medulla • Decreased glomerular filtration rate • Decreased overall renal tissue

3. Serum CR remains unchanged b/c skeletal muscle mass declines • Glomeruli decrease by over 33%; overall mass about 30% • Renal cortex is sensitive to loss of vascularity, but medulla is spared • GFR increases slightly; compensatory mechanism resulting from shift of renal perfusion from cortex to medulla.

4. Which of the following statement regarding cardiovascular changes associated with aging is FALSE? • There is a modest decrease in resting cardiac index. • The maximal heart rate is age limited. • There is a myocardial muscle atrophy • There is decreased ventricular compliance. • There is impaired diastolic relaxation.

5. Heart does not atrophy w/age; heart size and myocardial tissue mass actually increases • Decrease in cardiac index is not a degenerative process, but rather a result of reduced systemic requirements (decreased muscle mass and organ tissue mass) • Decreased compliance and diastolic dysfunction create dependency on synchronous atrial contraction (NSR) for adequate end-diastolic filling

6. Which of the following statements regarding anesthetic requirments in the elderly is TRUE? • The median effective dose (ED50) for neuromuscular blocking agents is reduced. • A reduced volume of local anesthetic is required for spinal anesthesia. • Parenteral morphine requirments are directly related to patient age. • Minimum alveolar concentration (MAC) values decline >75% than in young adulthood. • The brain becomes more sensitive to etomidate and less sensitive to narcotics.

7. Despite decreased skeletal muscle mass, ED50 of NMB agents is unchanged or even slightly higher • Elderly pts experience slightly higher levels of spinal anesthesia than young pts when given an equivalent dose of spinal LA • Parenteral morphine requirments are inversely related to pt age, and independent of body weight. • MAC values decline by up to 30 % from young adulthood to geriatric age.

8. Which of the following statements regarding the cardiovascular system and aging is/are true? • There is elastic replacement of fibrous tissue within the cardiovascular system. • Vascular impedance increases • Ventricular wall hypertrophy occurs only as a result of arterial hypertension. • Maximal cardiac output decreases.

9. Fibrotic replacement of elastic tissue can cause arterial hypertension • Fibrotic vessels also cause increased vascular impedance to cardiac ejection, which • Can lead to LVH, even in absence of hypertension • Elderly pts have a lower limit of max CO

10. Which of the following statements regarding the pulmonary system in the geriatric patients is/are TRUE? • Pulmonary shunting increases • Pulmonary deadspace increases • Vital capacity decreases • Lung elasticity decreases • All of the above

11. Which of the following statements regarding the pulmonary system in elderly patients is/are TRUE? • Closing capacity typically becomes greater than the volume of the lung at rest. • Hypoxic pulmonary vasoconstriction remains intact during general anesthesia • Elderly patients are predisposed to acute postoperative ventilatory failure • The cardiovascular and ventilatory responses to hypoxia are increased onset

12. Emphysemal-like changes occur in elderly pts: loss of elasticityincreased compliance, increased closing capacity (loss of elastic recoil)

13. Residual volume increase –>vital capacity decreases • Increased anatomic and alveolar dead space results from breakdown of alveolar septae and loss of total alveolar surface area • GA depresses hypoxic vasoconstriction • Increased work of breathing due to bone calcification and chest wall stiffness predisposes them to post-op failure • Cardiopulmonary system responds more slowly to hypoxia and hypercarbia

14. Which of the following statements regarding an 80 year old patient compared with a 20 year old patient is/are true? • Liver tissue mass decreases by 40% • Renal blood flow decreases by 50% • Glomeruli decreases by 30% • Renal tissue mass decreases by 30 %

15. Which of the following statements regarding central nervous system changes in elderly patients is/are True? • The adult brain weight is 20% less by age 80 years • The cerebrospinal fluid decreases in the 80yo • There is a > 30% decrease of the neuronal population of the cerebral cortex • Cerebral blood flow in the gray matter is maintained in the elderly patient

16. Decrease in brain matter results in compensatory increase in CSF volume • Neuronal population of the cerebral cortex decreases by 30-50% • CBF in the gray matter declines 20-30%

17. Which of the following statements regarding the peripheral nervous system in the elderly patient is/are TRUE? • The postjunctional muscle membrane is thicker • The dose requirements for competitive neuromuscular blocking agents are not significantly reduced • Motor nerve conduction velocity decreases • The total number of acetylcholine receptors increases

18. Which of the following statements regarding the geriatric patients and neuromuscular blocking agents is/are TRUE? • The time to onset of neuromuscular blockade is decreased • The dose requirement decreases in parallel with age-related decline in skeletal muscle mass • Age is the primary determinant of the completeness of antagonism of neuromuscular block • The clinical duration of action of most neuromuscular blocking agents is increased

19. Which of the following statements regarding the nervous system in the aged is/are TRUE? • The contractile properties of peripheral vascular smooth muscle remain intact • Cortisol secretion declines at least 15% • Endogenous beta-blockade occurs • Plasma concentrations of norepinephrine are 2 to 4 times greater than in younger patients

20. NE concentrations are 2 to 4 times higher, but responsiveness of beta-receptors is reduced, leading to an “endogenous b-blockade” • Alpha and muscarinic receptors remain largely intact, thus vascular smooth muscle contractile properties are not affected • Adrenal tissue atrophy leads to 15% decline in cortisol levels