Special Populations Flashcards
Geriatric PK
>65yo ↓total body water 53% ↓lean body mass 12% (lose muscle) ↑body fat M 38-45% F 36-38% ↓serum albumin 3.8g/dL ↓plasma protein = impaired protein binding ↓kidney weight 80% ↓GFR ↓hepatic blood flow 55-60% ↓circulation time = longer onset ↑duration extended d/t metabolism/elimination changes ↓MAC 6% each decade after 40yo
Postop Delirium
Most common postop complication
Assess preop cognitive function
Prevention = key
Avoid benzodiazepines
Geriatric Considerations
Polypharmacy Potential drug interactions w/ anesthesia Renal impairment ↓plasma protein ↓gastric motility Avoid drugs w/ anticholinergic effects
Muscle Relaxants
ELDERLY
↓skeletal muscle mass
Delayed onset
Extended DOA
Anticholinergics
Tricyclic antidepressants Antihistamines Antimuscarinics Antispasmodics 1st generation antipsychotics H2-receptor antagonists Skeletal muscle relaxants Antiemetics
Regional Anesthesia
ELDERLY
Anatomic changes in epidural & subarachnoid space
↓diameter & number myelinated fibers
↑dura permeability
↓CSF volume
Fixed dose & volume LA block spreads higher
Obesity
Differences in tissue distribution Hemodynamics Blood flow to tissues Plasma composition Liver & kidney function
IBW
Height (cm) - 100 M
Height (cm) - 105 F
Lean Body Weight
LBW
= IBW + 30%
Adjusted Body Weight
ABW
= IBW + 40%
IV Anesthetics
OBESITY
Thiopental TBW prolonged DOA & 1/2 life
Propofol LBW induction
Maintenance TBW
Midazolam TBW loading dose (higher to achieve initial therapeutic effects)
Maintenance IBW
Dexmedetomidine 0.2mcg/kg/min ↓infusion dose to prevent cardiac SE
Muscle Relaxants
OBESITY
Succinylcholine TBW
↑pseudocholinesterase activity
Non-depolarizing IBW
Hydrophilic
Narcotics
OBESITY
Fentanyl ?
TBW dosing overestimates
Sufentanil TBW loading dose
Maintenance LBW
↑Vd & prolonged elimination 1/2 life
Remifentanil IBW
Not effected by weight
Pediatric Drug Distribution
↓protein concentration Blood-brain barrier ↑CBF GFR 40mL/min at birth ↑100mL/min at 1yo
Neonates/Infants
↓muscle mass ↑fat stores
↑blood flow to central organs (brain, heart, liver, kidneys)
Water-Soluble Drugs
PEDIATRICS
↑dose required
Succinylcholine
Cell Cycle
- Cell growth
- DNA synthesis
- Mitosis
Chemotherapy Patients ALL Experience
Nausea & vomiting
Cisplatin
Lung, breast, ovarian, & bile duct cancers
Nephrotoxicity, peripheral neuropathy, nerve dysfunction
Methotrexate
Lymphomas, breast, & bladder cancers
Myelosuppression w/ neutropenia & thrombocytopenia
Bleomycin
Hodgkin’s & non-Hodgkin’s lymphoma
PULMONARY FIBROSIS
Doxorubicin
Lymphomas, lung, ovarian, & thyroid cancers
Cardiotoxicity & myelosuppression
Cetuximab
Colon & GI cancers
Interstitial lung disease
Suppress NK Cell Activity
Volatiles
Barbiturates
Ketamine
Promote cancer cell mets
Nitrous Oxide
Reduces purine & therefore DNA synthesis
Suppresses neutrophil chemotaxis, potentially facilitating cancer spread
Opioids
Cellular & humoral immunosuppression
1° MORPHINE
Propofol
PROTECTIVE EFFECTS Anti-inflammatory effect Inhibit COX-2 PGE-2 reduction Weak β adrenoreceptor binding Enhance antitumor immunity NK function preservation
Local Anesthetics
Reduce metastatic burden
Cancer Surgery
IMMUNOSUPPRESSION
Stress HPA stimulation Inhaled anesthetics Thiopental/Ketamine Opioids & pain Hypothermia Blood transfusion Inflammation Catecholamine
PROLIFERATION
RECURRENCE
METASTASIS
Cancer Surgery
INHIBITION
Regional anesthesia Local anesthetics Naltrexone COX-inhibitors β blockers
