vdocuments.mx_geriatric-anesthesia-56c68a0e6d674.ppt

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1. Geriatric Anesthesia
SC 李侑珊
石博元
VS 鄭雅蓉

2. Brief HistoryBrief History

99 y/o female with 99 y/o female with
1.1.Large bedsore for 5 months s/p debridementLarge bedsore for 5 months s/p debridement
2.2.Old right femoral fracture s/p Moore hemiarthOld right femoral fracture s/p Moore hemiarth
roplasty on 1995roplasty on 1995
3.3.OsteoporosisOsteoporosis
4.4.DementiaDementia
No other systemic illnessNo other systemic illness

3. CXRCXR

4. Anesthesia recordAnesthesia record

5. Anesthesia recordAnesthesia record
AgentAgent Given doseGiven doseRegular doseRegular dose
fentanylfentanyl 1 ml1 ml 2 ml2 ml
propofolpropofol 50 mg50 mg 80-90 mg80-90 mg
rocuroniumrocuronium 20 mg20 mg 40 mg40 mg
atropineatropine 0.4 mg0.4 mg 0.4 mg0.4 mg
EnlonEnlon 28 mg28 mg 32-40 mg32-40 mg

6. Age, Minimum Alveolar Anesthetic Age, Minimum Alveolar Anesthetic
Concentration, and Minimum AlveConcentration, and Minimum Alve
olar Anesthetic Concentration-Awolar Anesthetic Concentration-Aw
akeake
Eger, Edmond I II, MDEger, Edmond I II, MD
Anesth Analg. 2001 Oct;93(4):947-53 Anesth Analg. 2001 Oct;93(4):947-53

8. Geriatric AnesthesiaGeriatric Anesthesia
Age related anatomic & Age related anatomic &
Physiologic ChangesPhysiologic Changes

9. Cardiovascular system and Cardiovascular system and
Autonomic Nervous System Autonomic Nervous System
(1)(1)
1.1.Decline in the responsiveness of Decline in the responsiveness of ββ- receptors- receptors
- plasma catecholamine level unchanged- plasma catecholamine level unchanged
- decrease in beta-adrenergic receptors density(?)- decrease in beta-adrenergic receptors density(?)
- 75y/o vs. 25y/o, 20% decrease of maximal HR - 75y/o vs. 25y/o, 20% decrease of maximal HR
2.2.Progressive replacement of supple, functional carProgressive replacement of supple, functional car
diac and vascular tissue (a. &v) by stiff, fibrotic mdiac and vascular tissue (a. &v) by stiff, fibrotic m
aterialaterial
-- elevated afterloadelevated afterload
- elevated systolic BP- elevated systolic BP
- LV hypertrophy- LV hypertrophy

10. Cardiovascular system and Cardiovascular system and
Autonomic Nervous System Autonomic Nervous System
(2)(2)
3.3.Decreased cardiac outputDecreased cardiac output
4.4.Decreased baroreceptor reflexDecreased baroreceptor reflex
These factors render the elderly patients These factors render the elderly patients
less capable of defending their CO and BP less capable of defending their CO and BP
against the usual periop challenges. against the usual periop challenges.

11. Respiratory System (1)Respiratory System (1)
1.1.a decline in elasticity of the bony thoraxa decline in elasticity of the bony thorax
•Increased residual volumeIncreased residual volume
•Decreased vital capacityDecreased vital capacity
•Increased dead spaceIncreased dead space
2.2.a loss of muscle mass with weakening a loss of muscle mass with weakening
of the muscles of respirationof the muscles of respiration
•FEV1 decreases progressively with agingFEV1 decreases progressively with aging
•ratio of FEV to TLC of the elderly decreases. ratio of FEV to TLC of the elderly decreases.
(70% vs. >80%)(70% vs. >80%)

12. Respiratory system (2)Respiratory system (2)
1.1.a decrease in alveolar gas exchange surfa decrease in alveolar gas exchange surf
aceace
2.2.a decrease in central nervous system resa decrease in central nervous system res
ponsivenessponsiveness
•Ventilatory response to hypercapnia and hypVentilatory response to hypercapnia and hyp
oxia is blunted in the elderly (1/2 of 25y/o)oxia is blunted in the elderly (1/2 of 25y/o)
•Thus, we need to increase FIO2 and tidal volThus, we need to increase FIO2 and tidal vol
ume (watch out for oxygen toxicity and barotrume (watch out for oxygen toxicity and barotr
auma)auma)

13. Renal SystemRenal System
1.1.Decreased renal mass, mainly in the corteDecreased renal mass, mainly in the corte
xx
2.2.Decreased renal blood flowDecreased renal blood flow
Due to glomerulosclerosisDue to glomerulosclerosis
RPF and GFRRPF and GFR↓↓
3.3.Decreased tubular functionDecreased tubular function
impaired fluid handlingimpaired fluid handling
decreased concentrating abilitydecreased concentrating ability
decreased diluting capacitydecreased diluting capacity
impaired sodium handlingimpaired sodium handling
decreased drug excretiondecreased drug excretion

14. LiverLiver
1.1.There is a lack of correlation There is a lack of correlation
between structural and functional between structural and functional
data concerning the aging liver, as data concerning the aging liver, as
a decline in organ volume does not a decline in organ volume does not
necessarily reflect impaired necessarily reflect impaired
metabolic function.metabolic function.
2.2.Reduced hepatic drug clearance is Reduced hepatic drug clearance is
common in the elderly common in the elderly

15. Nervous System (1)Nervous System (1)
Effects of aging on the nervous system Effects of aging on the nervous system
include: include:

a general loss of neuronal substancea general loss of neuronal substance

a decrease in the number of peripheral neura decrease in the number of peripheral neur
onsons

muscles innvervated by fewer axons, leadinmuscles innvervated by fewer axons, leadin
g to possible denervation atrophyg to possible denervation atrophy

conduction velocity is slightly affected by agiconduction velocity is slightly affected by agi
ng (slower)ng (slower)

16. Nervous System (2)Nervous System (2)

increased sensitivity to opioid analgesiincreased sensitivity to opioid analgesi
cscs

decreased cell density, lower cerebral decreased cell density, lower cerebral
oxygen consumption and lower cerebroxygen consumption and lower cerebr
al blood flowal blood flow

17. Geriatric AnesthesiaGeriatric Anesthesia
Age related pharmacologic Age related pharmacologic
changeschanges

18. Pharmacokinetic and pharmacodynamic differePharmacokinetic and pharmacodynamic differe
nces in the elderly (1)nces in the elderly (1)

Protein binding:Protein binding:
–Circulating level of serum protein Circulating level of serum protein
(especially albumin) decreases in quantity(especially albumin) decreases in quantity
–Qualitative change of serum protein reduce Qualitative change of serum protein reduce
the binding effectiveness of the available the binding effectiveness of the available
protein.protein.
–This will lead to higher free drug levels and This will lead to higher free drug levels and
an enhanced delivery of the drug to the an enhanced delivery of the drug to the
brain.brain.

19. Pharmacokinetic and pharmacodynamic diffPharmacokinetic and pharmacodynamic diff
erences in the elderly (2)erences in the elderly (2)

Changes in body compartmentChanges in body compartment
–Age-related changes in body composition Age-related changes in body composition
include a loss of skeletal muscle and an include a loss of skeletal muscle and an
increase in percentage of body fat.increase in percentage of body fat.
–Increased availability of lipid storage sites, Increased availability of lipid storage sites,
this will leads a gradual elution of these this will leads a gradual elution of these
agents from the storage sites.agents from the storage sites.

20. Pharmacokinetic and pharmacodynamic Pharmacokinetic and pharmacodynamic
differences in the elderly (3)differences in the elderly (3)

Heaptic and renal functionHeaptic and renal function
–Hepatic and renal function are reduced about 1Hepatic and renal function are reduced about 1
% per year beyond 30.% per year beyond 30.
Elimination half-lifeElimination half-life
DrugDrug Young adultYoung adult Old adultOld adult
FentanylFentanyl 250min250min 925min925min
DiazepamDiazepam 24hrs24hrs 72hrs72hrs
midazolammidazolam 2.8hrs2.8hrs 4.3hrs4.3hrs
vecuroniumvecuronium 16min16min 45min45min

21. Induction Agent (1)Induction Agent (1)

ThiopentalThiopental
–Administration of IV barbiturates produces the peAdministration of IV barbiturates produces the pe
ripheral vasodilatation with a moderate BP decreripheral vasodilatation with a moderate BP decre
ase.ase.
–With a decreased baroreceptor reflex and increasWith a decreased baroreceptor reflex and increas
ed vascular wall rigidity, the drug may cause a daed vascular wall rigidity, the drug may cause a da
ngerous drop in BP.ngerous drop in BP.
–In the elderly, elimination half-life is 13-25 hrs(6-1In the elderly, elimination half-life is 13-25 hrs(6-1
2 hrs in the young)2 hrs in the young)
–The thiopental dose requirement may decrease 2The thiopental dose requirement may decrease 2
5-75 percent.5-75 percent.

22. Induction Agent (2)Induction Agent (2)

MethohexialMethohexial
–Methohexial is rapid acting and has a higMethohexial is rapid acting and has a hig
her hepatic clearance rate and shorter eliher hepatic clearance rate and shorter eli
mination time than thiopental.mination time than thiopental.
–More suitable for outpatient surgery.More suitable for outpatient surgery.

23. Induction Agent (3)Induction Agent (3)

PropofolPropofol
–Propofol produces greater decrease in Propofol produces greater decrease in
systemic BP than thiopental .systemic BP than thiopental .
–Injecting the propofol slowly with sufficient Injecting the propofol slowly with sufficient
time can minimize the effect of cardiovascular time can minimize the effect of cardiovascular
depression.depression.
–Studies show patients older than 80 exhibit Studies show patients older than 80 exhibit
less post-anesthetic mental impairment with less post-anesthetic mental impairment with
propofol than other agents. propofol than other agents.
–Induction: using 1.2-1.7 mg/kg in the elderly Induction: using 1.2-1.7 mg/kg in the elderly
(versus 2.0-2.5 mg/kg in younger patients)(versus 2.0-2.5 mg/kg in younger patients)

24. Muscle Relaxant (1)Muscle Relaxant (1)

Aging affects the neuromuscular juncAging affects the neuromuscular junc
tion in many ways:tion in many ways:
1.1.The distance of the junction ↑The distance of the junction ↑
2.2.The number of ACh vesicle ↓The number of ACh vesicle ↓
3.3.Receptors of ACh ↓Receptors of ACh ↓
4.4.Sensitivity of ACh receptors —Sensitivity of ACh receptors —

25. Muscle Relaxant (2)Muscle Relaxant (2)

SuccinylcholineSuccinylcholine
–This agent is metabolized by pseudocholiThis agent is metabolized by pseudocholi
nesterase which is not affected by the aginesterase which is not affected by the agi
ng process.ng process.
–The response of succinylcholine is unalterThe response of succinylcholine is unalter
d with aging.d with aging.

26. Muscle Relaxant (3)Muscle Relaxant (3)
Non-depolarizing muscle relaxantNon-depolarizing muscle relaxant

Long-acting agents:Long-acting agents:
–Metocurine, pancuronium (renal)↑Metocurine, pancuronium (renal)↑
–Doxacurium, pipecuronium (renal) —Doxacurium, pipecuronium (renal) —

Intermediate-acting agentsIntermediate-acting agents
–Vecuronium, rocuronium ↑Vecuronium, rocuronium ↑
–Atracurium, cisatracurium (Hoffmann elimAtracurium, cisatracurium (Hoffmann elim
ination)— ination)—

27. Muscle Relaxant (4)Muscle Relaxant (4)

The use of the The use of the intermediate-acting intermediate-acting
agentagent is prudent, because even the is prudent, because even the
duration of one single dose of long-duration of one single dose of long-
acting agent may be too prolonged acting agent may be too prolonged
for the planned surgery.for the planned surgery.

Fewer doseFewer dose of non-depolarizing of non-depolarizing
muscle relaxant will be required.muscle relaxant will be required.

28. Opioids (1)Opioids (1)

Increases in potency for alfentanil, fentIncreases in potency for alfentanil, fent
anyl, and remifentanil were demonstratanyl, and remifentanil were demonstrat
ed in EEG studies.ed in EEG studies.

A reduction in dosage in the elderly woA reduction in dosage in the elderly wo
uld be recommended.uld be recommended.

29. Opioids (2)Opioids (2)

FentanylFentanyl
–Dose should be reduced to ½ to achieve tDose should be reduced to ½ to achieve t
he same effect.he same effect.

AlfentanilAlfentanil
–Same recommendation as fentanyl.Same recommendation as fentanyl.

30. Volatile agents (1)Volatile agents (1)

Ventilation perfusion mismatch will Ventilation perfusion mismatch will
decrease the rate of action.decrease the rate of action.

Decreased cardiac output will make Decreased cardiac output will make
the onset of the action more rapid.the onset of the action more rapid.

Recovery from anesthesia with a Recovery from anesthesia with a
volatile agent may be prolonged volatile agent may be prolonged
because of an increased volume of because of an increased volume of
distribution (increased body fat).distribution (increased body fat).

31. Volatile agents (2)Volatile agents (2)

The MAC of inhalational agents is reduceThe MAC of inhalational agents is reduce
d by 6% per decade of age over 40 years.d by 6% per decade of age over 40 years.

The lower lipid-solubility of sevoflurane anThe lower lipid-solubility of sevoflurane an
d desflurane has advantage in the elderly:d desflurane has advantage in the elderly:
–More rapid control of anesthetic depth than higher lipiMore rapid control of anesthetic depth than higher lipi
d-solubility agents.d-solubility agents.
–A faster emergence from anesthesia. (desflurane vs. A faster emergence from anesthesia. (desflurane vs.
isoflurane: 5.4 vs. 7 mins)isoflurane: 5.4 vs. 7 mins)

32. SummarySummary

33. Anesthesia RecordAnesthesia Record
AgentAgent Given doseGiven doseRegular doseRegular dose
fentanylfentanyl 1 ml1 ml 2 ml2 ml
propofolpropofol 50 mg50 mg 80-90 mg80-90 mg
rocuroniumrocuronium 20 mg20 mg 40 mg40 mg
atropineatropine 0.4 mg0.4 mg 0.4 mg0.4 mg
EnlonEnlon 28 mg28 mg 32-40 mg32-40 mg

34. Thank you for your Thank you for your
AttentionAttention