Anesthetic management in older adults (≥65 yr)
🎯 Core concept
- Aging
→ ↓ physiologic reserve ทุกระบบ
- → ↑ sensitivity ต่อ anesthetic
+ ↑ complication
- Frailty
+ comorbidity สำคัญกว่า “อายุ” เพียงอย่างเดียว
🧠 Physiologic changes
(high-yield)
1. CNS
- ↑ sensitivity ต่อยา
(propofol, opioid, benzo)
- ↓ MAC (minimum
alveolar concentration) ~6%/decade (>40 yr)
- ↓ ventilatory response → ↑ risk respiratory depression
- ↑ risk delirium / PND
2. Cardiovascular
- vascular
stiffening → BP
labile
- ↓ baroreflex → hypotension easily
- diastolic
dysfunction → fluid
sensitive
- AF → hemodynamic collapse ได้ง่าย
3. Respiratory
- ↓ lung elasticity + ↑ V/Q mismatch
- ↓ PaO₂
baseline
- ↑ risk:
- hypoxia
- hypercapnia
- aspiration
4. Renal / hepatic
- ↓ clearance → drug accumulation
- creatinine
อาจ “ดูปกติ” แต่ GFR ↓
5. Pharmacokinetics
- ↓ TBW → ↑ plasma drug conc
- ↑ fat → prolonged drug effect
- ↓ clearance → accumulation
👉 สรุป:
ต้องลด dose + spacing
🔴 Preoperative assessment
(ต้องทำ)
1. Frailty (สำคัญมาก)
- prevalence
~30–50%
- predictor:
- mortality
↑ (OR ~6)
- delirium
↑
- LOS ↑
2. Cognitive function
- screen
(Mini-Cog / MMSE)
- baseline
for postop comparison
3. Functional capacity
- poor
function → ↑ cardiac risk
4. Anemia
- common
- ↑ mortality (even mild
anemia)
5. Medication review
- polypharmacy
→ high risk adverse
events
6. Palliative consideration
- high-risk
→ discuss goals of
care
🟡 Premedication
- ❌
Avoid benzodiazepines (delirium)
- ✅
ใช้ multimodal analgesia (acetaminophen, COX-2)
🟢 Choice of anesthesia
- GA vs
regional → no clear
superiority
- เลือกตาม:
- surgery
- comorbidity
- cooperation
🔵 INTRAOPERATIVE
MANAGEMENT
1. Dosing principle (สำคัญที่สุด)
- ลด dose ทุกตัว:
- induction
↓ ~40–50%
- maintenance
↓
- เพิ่ม interval dosing
- ใช้ short-acting drugs
2. Key drugs
Propofol
- sensitivity
↑ ~30%
- dose
↓ 40–50%
Etomidate
- เหมาะใน unstable hemodynamics
Opioids
- potency
↑ ~2×
- ↓ dose + monitor respiration
Benzodiazepine
- ❌
avoid / minimal
Meperidine / anticholinergic
- ❌
avoid (delirium)
3. Inhalation agents
- MAC ↓ with age (~30% at 90 yr)
- ต้อง titrate carefully
4. Neuromuscular blocker
- duration
↑
- ต้อง monitor + ensure reversal
5. Hemodynamic
- avoid
hypotension (critical)
- older
pts → need higher MAP
sometimes
6. Temperature
- ↑ risk hypothermia → coagulopathy
7. Positioning
- ↑ risk nerve injury / skin
breakdown
🔶 POSTOPERATIVE
MANAGEMENT
Pain control (balance สำคัญ)
- opioid:
- ↓ dose
- titrate
slowly
- ใช้ multimodal:
- acetaminophen
- NSAIDs
(ระวัง renal / GI / CV)
👉 Pain uncontrolled → delirium
👉
opioid excess → delirium
Delirium prevention
- avoid
high-risk drugs
- early
mobilization
- optimize
sleep / hydration
⚠️ Major complications
1. Mortality
- ↑ with:
- frailty
- emergency
surgery
- heart
failure
2. Pulmonary
- atelectasis,
pneumonia, RF
3. AKI
- ↑ risk significantly
4. Delirium
- 4–55%
- ~40%
ไม่กลับ baseline
🧠 Clinical pearls
- 👴
“Treat physiology, not age”
- 📉
Frailty > age ในการทำนาย outcome
- 💉
ลด dose ยาทุกตัว (rule of thumb)
- 🫀
BP instability = common + dangerous
- 🫁
respiratory depression = major risk
- 🧠
delirium = common + preventable
🧭 Take-home message
Older adults = high-risk physiology + high drug
sensitivity
👉 key strategy:
- careful
preop assessment (frailty + cognition)
- conservative
dosing
- strict
hemodynamic control
- delirium
prevention
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