Geriatrics Flashcards
What age defines elderly?
> 65yo
What are the 5 key elements involved in aging biology?
- Genes
- Nutrition
- Lifestyle
- Environment
- Chance
What length is related to mortality?
Telomeres are typically long
Shortened telomere indicates shorter lifespan
Premature shortening associated w/ dementia
Oxidative Damage
Free radicals (reactive oxygen species) oxygen use/metabolism byproducts can damage chromosomal DNA → impair gene function, damage to mitochondrial DNA, & damage telomeres
Parkinson’s
Protein malfunction
Lewy bodies
α synuclein
Alzheimer’s
Protein dysfunction
β amyloid
CNS
Mood, memory, & motor function changes
Neuronal death, synaptic loss, glial cell reactivity
↓neuronal regenerative capacity
Brain mass ↓15% ↑CSF volume
↓nerve conduction velocity
Impaired cholinergic signaling & Dopamine signal transduction pathways
↓α2 agonist receptors
Peripheral nerve cell degeneration
↓myelinated fibers
↑risk postop delirium or cognitive dysfunction
↓neurotransmitter activity (glutamate receptors & GABAa binding sites)
↓CBF & cerebral metabolic rate
↑susceptibility to metabolic stress
Cognitive dysfunction r/t aging
Intellectual functioning, attention, memory, & psychomotor function decline w/ age
Glutamate
Excitatory
GABA
Gamma aminobutyric acid
Inhibitory
CNS
Anesthetic Considerations
↑drug sensitivity
Receptor down-regulation
Blood-brain barrier more permeable (drugs cross more readily)
Exaggerated response to CNS depressants (GA, hypnotics, opioids, benzodiazepines)
↓induction agents 25-50%
Neuraxial
Anesthetic Considerations
Neural damage risk d/t ↓myelinated nerve fibers
Difficult neuraxial placement d/t anatomic changes
Dura more permeable to LA
↓CSF volume
Enhance LA spread
Post-spinal sympathectomy → severe hypotension refractory to adrenergic stimulation
↓spinal/epidural block LA dose
Cardiovascular System
↓tissue elasticity (less compliant)
↑collagen cross-linked & fragmented elastin ↑tissue stiffness
↓end-organ adrenergic responsiveness
↑afterload
↑systolic BP 5mmHg per decade until 60yo then 10mmHg per decade
LV hypertrophy ↑L ventricular mass
Diastolic dysfunction
↓cardiomyocytes
↑heart failure incidence
Aortic sclerosis & stenosis
Electrical system declines - pacemaker cells (SA node) reduced, ↑dysrhythmias, bradycardia, less responsive to Atropine, ↑pacemakers or AICD incidence
What are 2 major structural changes in blood vessels?
STIFFENING & ATHEROSCLEROSIS
Atherosclerosis hallmark sign = inflammation → artery occlusion
Cardiac Supply & Demand
MISMATCH
Myocardium prone to ischemia
↑LVEDP + ↓ADBP → ↓O2 supply
Ventricular hypertrophy, LV end-systolic pressure, ↑aortic pressure, & ↑systole → ↑O2 demand
CV
Anesthetic Considerations
↓end-organ adrenergic responsiveness
Impaired ability to compensate in response to hypotension, hypovolemia, & hypoxia
Prolonged circulation time - faster inhalational induction & delayed IV onset
HTN → periop complications risk factor
↓venous compliance ↓VR
↓SV/CO
↓sensitivity to β adrenergic modulation
What is the most common complication & leading cause of death in the postop period?
Myocardial infarction
Respiratory System
↓chest wall compliance ↓Pel (lung elastic recoil) ↑compliance ↑VC/RV/CV/FRC CV > FRC supine 45yo upright 65yo TLC Ø difference or slight ↓ ↓expiratory flows (FEV1 & FEF 75%) Small airway diameters Airway collapse w/ forced expiration ↓respiratory muscle endurance
FEV1
Forced expired volume in 1 second
FEF 75%
Forced expired flow at 75%
Gas Exchange
↓alveolar surface area ↓PaO2 ↑Va/Q mismatch ↑intrapulmonary shunting ↓Pel (emphysema presentation) ↑airway closure CV approached Vt CV > FRC Prone to atelectasis
What is impaired at the alveolar level?
↓oxygen exchange
Closing capacity & FRC at 45yo
FRC supine = closing capacity
FRC upright > closing capacity
*FRC impacted w/ position changes ↓when patient supine
Closing capacity & FRC at 65yo
FRC supine < closing capacity
FRC upright = closing capacity\
*FRC impacted w/ position changes ↓when patient supine
Other Respiratory Changes
↓ability to clear secretions ↑aspiration risk ↓respiratory drive in response to hypoxia, hypercarbia, & resistive load Predisposed to ↑apnea episodes ↑airway reactivity
Renal System
Kidney parenchymal tissue atrophy ↓RBF & renal mass ↓drug clearance ↓GFR 1mL/yr Dilute urine (unable to maximally concentrate) Tubular frailty - more susceptible to hypoxic or nephrotoxic injury Impaired Na+ conservation ↓renin/aldosterone production Prone to fluid overload or dehydration Unable to accommodate hemodynamic changes - more susceptible to injury ↓sensitivity to volume/osmoreceptor Diminished thirst response Bladder dysfunction/incontinence
What is the best indicator of drug clearance?
Creatinine clearance
What are renal failure patients at ↑risk to experience?
- Fluid overload
- Metabolite & drug accumulation
- ↓drug elimination
- Prolonged anesthetic drugs & adjuncts effects
- Electrolyte imbalances
- Arrhythmias
Hepatic System
↓liver mass 20-40%
↓hepatic blood flow & functional hepatic reserve
Altered drug metabolism & protein binding
↓metabolism → prolonged half-life
↓↑↓↓↓↑↑↓↑ →
Phase 1
Variable
Oxidation, reduction, & hydrolysis
CYP450 enzyme
Phase 2
Not significantly altered
Conjugation, sulfonic acid, or acetylation
Serum albumin _____ & α1 acid glycoprotein _____
Decreases & increases
Gastrointestinal System
↓motility & colonic function
↓GI immunity & drug metabolism
Liver function impact on NPO status
Immune System
Innate & adaptive changes ↓immune cells bactericidal activity ↑cytokine & chemokine levels Low-grade chronic inflammatory process ↓T & B cell function Impaired ability to fight infection & control cancers
Endocrine System
Endocrine gland atrophy
↓hormone production
Impaired endocrine function & glucose homeostasis
Insulin, thyroxine, growth hormone, renin, aldosterone, & testosterone deficiencies
Chronic electrolyte abnormalities
Diabetes, hypothyroidism, impotence, & osteoporosis
↓lean body mass
Resting Metabolic Rate
↓1% per year after 30yo
Total energy expenditure ↓
*↑energy expenditure w/ multiple comorbidities & chronic illness
Unable to tolerate ↓O2 demand
Pancreas
↓pancreatic islet β cells number & function
↓insulin secretion & peripheral insulin resistance
↑hepatic glucose production
Impaired fat/protein production
What is a major risk factor for CV disease?
Diabetes
- Risk periop & postop complications
- Impaired cognition/dementia
Body Composition
↓intracellular fluid & blood volume → hypotension
↓muscle mass & reduced strength
↑fat % per total body weight
Atrophy → 1° impact fast-twitch muscle fibers
Loss body protein & motor neurons
↑waist circumference
Fat accumulation w/in muscles
↓collagen, elastin, SQ fat, dermal/epidermal skin thickness
Prone to skin tears & nerve injuries
↑↓↑↓↑↑↓↑ → ↑↓↑ → ↔ α ⋅ β Ø λ π η
How to prevent skin tears & nerve injuries?
Careful positioning
Thermoregulation
Impaired
↓hypothalamus function
Hypothermia more pronounced & lasts longer
Less effective peripheral vasoconstriction
Prolonged recovery from anesthesia
Impaired coagulation & immune function
Blunted ventilatory response to CO2
↑shivering incidence → O2 consumption & basal metabolic rate → hypoxia, acidosis, & CV compromise
Frailty
Reduced physiologic reserve - associated w/ ↑disability susceptibility
↑vulnerability to adverse outcomes d/t ↓resistance to stressors
1° or 2°
Weight loss, fatigue, impaired grip strength, low physical activity, & slow gait
Decompensate more quickly
Frailty index predicts outcomes in non-surgical elderly population (preop risk assessment)
Periop risk factor r/t postop complications ↑LOS & discharge to skilled/assisted living facility
Dementia
Intellectual decline
Changes in cognitive, behavioral, or health status
Degenerative brain diseases often incurable
Supportive therapy/treatment
Reversible Dementia
Chronic drug intoxication Vitamin deficiency Subdural hematoma Major depression Hydrocephalus Hypothyroidism
Falls
Unstable gait Poor muscle strength Neural damage in basal ganglia & cerebellum Peripheral neuropathy Fall history → evaluate gain & balance
PK/PD
Polypharmacy Loss neuronal tissue & receptor changes ↑sensitivity ↓anesthesia requirements Consider BIS monitor Anesthetic toxicity & cognitive dysfunction
Anesthesia Management
↓Vd ↑plasma concentration ↑body fat ↓muscle mass ↓plasma albumin Impaired renal function ↑serum concentration & prolonged drug effects (renal dependent elimination)
Inhalational Anesthetics
↓MAC 6% per decade after 40yo
N2O ↓8% per decade
Propofol
↓induction dose 50% ↓infusion 20%
↑effect on hemodynamics
↓clearance (women > men)
Etomidate
Ideal drug (CV stable) Less hemodynamic instability ↓Vd ↓clearance ↑sensitivity ↓induction dose NO analgesic properties
Thiopental
↓total dose 50-80%
↓Vd
Delayed recovery d/t ↓central Vd
Midazolam
↑sensitivity MOA unknown
↑DOA
Contributes to postop delirium
Hydroxymidazolam metabolite potential accumulation w/ ↓renal function
Opioids
↑sensitivity
↓hepatic metabolism
↓renal excretion
Metabolites (pharmacologically active Codeine, Morphine, & Meperidine) → analgesia & side effects
Fentanyl
↑potency 50% > 80yo
↑sensitivity
↓dose
PD > PK
Remifentanil
Not dependent on liver or renal function ↓50% by 85yo ↓bolus dose 1/2 Infusion rate 1/3 Slower on & off ↑PD sensitivity
Meperidine
NOT RECOMMENDED Normeperidine = active metabolite Renal excretion Half-life 15-30 hours Associated w/ postop delirium Postop shivering ↓dose
NMBDs
PD & ED95 not significantly altered
PK ↓onset maximal block ↓hepatic metabolism ↓renal excretion ↑recovery time 50%
Residual blockade effect on pharyngeal function
DOC = Cisatracurium
- Hoffman elimination & ester hydrolysis
- Not organ dependent
What is important to determine when providing informed surgical consent?
Decision-making capacity
What are the 4 legally relevant criterion for decision making?
- Understanding treatment options
- Appreciating & acknowledging medical conditions & outcomes
- Exhibiting reasoning/rational discussion of treatment options
- Clearly choosing a preferred treatment option
Autonomy
Patient right to self-determination
Beneficence
Obligation or responsibility to help the patient
Do Good
Nonmaleficence
Not intentionally harm the patient
Do not harm
Justice
Treat the patient fairly
DNR Status
Suspension - full or partial
No suspension
DNR Status
Suspension - full or partial
No suspension
Nutritional Status
25% malnutrition
- Associated w/ adverse health outcomes
- Postop complications
ETOH check vitamin B12 & folate levels
↓intake d/t taste loss & ↓appetite
↓lean body mass
Slower protein turnover
Severe nutritional risk:
> 10-15% weight loss over 6mos
BMI < 18.5kg/m^2
Serum albumin < 3g/dL
Functional Status
Poor functional status = surgical site infection & postop complications risk factor 25% > 65yo have impaired ADLs Up & go mobility test Review ADLs Assess hearing & vision
Cognitive Status
Assess cognitive ability, decision-making capacity, & postop delirium risk
Dementia history
- Mini cog = 3 item recall & draw a clock
- Advanced directives or surrogate decision maker
Beer’s Criteria
Drugs potentially harmful
AVOID:
- Metoclopramide (extrapyramidal effects)
- Meperidine
- NSAIDs (GI bleed)
- Transdermal Fentanyl → delirium & respiratory depression
- Agonist-antagonist opioids
- Methadone (long half-life → over-sedation or respiratory depression)
What increases w/ number of medications?
Risk of adverse events
- Assess current medications
- Chronic benzodiazepine
- OTC or herbal supplements
Anticholinergics associated w/ delirium & gait instability
Discontinue when possible
Emergency Surgery
Trauma, falls, hip fracture, intracranial bleeding, intra-abdominal, or vascular
Assess acute heart failure, acute lung injury, dehydration
↑O2 requirements
Worse outcomes than elective surgery - unable to optimize or perform full preop work-up
Intraop Management
Regional anesthesia ↓DVT incidence ↓Anesthetic requirements ↓induction doses 25% Avoid benzodiazepines Skin breakdown & ulcerations risk - positioning considerations Hypothermia risk
Fluid & Blood Therapy
Do not tolerate hypovolemia or hypervolemia
Hypovolemia → hypotension & organ hypoperfusion
Hypervolemia → HTN & CHF
↑Hgb/Hct goals
Postop Management
Postop delirium & POCD common after cardiac & non-cardiac surgery
15-55% hospitalized elderly patients
Postop Delirium & POCD
Rapid decline in LOC - difficulty focusing, shifting, or sustaining attention
Incoherent speech, memory gaps, disorientation, hallucination not explained by pre-existing dementia or impairment
Possible inflammatory response d/t surgical stress
Haloperidol short-term to control symptoms
POCD Risk Factors
Genetic disposition Lower education ↑ETOH intake or abuse Elderly ASA status Pre-existing mild cognitive impairment CVA history Cardiac surgery Surgery & anesthesia duration Intraop cerebral desaturation Postop infection
Postop Complications
Cardiac, pulmonary, or neurologic
- Emergency surgery
- # comorbidities
- Surgical procedure type
Postop Pain Control
Acute procedural pain vs. chronic pain
Identify source or cause - distended bladder, incision, infection, inflammation, fracture, positioning, UTI, or constipation
Periop Outcomes
- Surgical procedure risk
- Patient clinical risk factors
↑clinical risk factors ↑surgical procedure risk → overall poor outcomes risk
↑hospitalization
$$$
Elderly = worse outcomes
↑complication risk w/ CV surgery
2-5x mortality cardiac & non-cardiac surgery
Postop complication 60%
Prolonged mechanical ventilation
Atrial fibrillation more common
Surgical wound infection
Stroke 2x
Neurocognitive dysfunction
DELIRIUM COMMON AFTER MAJOR SURGERY
Functional recovery Ø norm
Patients commonly discharged to long-term rehab or nursing home
What is the leading cause of morbidity?
Pulmonary insufficiency or infection
KEY POINTS
Aging = progressive accumulation of random molecular defects
ALL major cells types in brain undergo structural changes (neuronal cell death, dendritic changes, synaptic loss) ↓brain mass ↑CSF
Blood vessels - stiff & thick + atherosclerosis
↑diastolic dysfunction w/ age (systolic dysfunction abnormal)
Closing volume approach Vt → atelectasis
Kidney susceptible to damage - unable to accommodate hemodynamic change or Na+/H2O imbalance
Frailty ↑susceptibility to disability
1. Procedures surgical risk
2. Number clinical risk factors
Delirium common after major surgery
↓anesthetic requirements
