Miscellaneous: Geriatrics

Cardiovascular Changes

• Decreased Cardiac Output (CO) & Cardiac Index (CI)
  • Decreased Number of Myocytes & Increased Collagen with Fibrotic Areas
  • Decreased Ventricular Compliance
  • Decrease 1% Per Year
• Decreased Sensitivity to Catecholamines (Less Vital Changes in Shock)
• Increased Systemic Vascular Resistance (SVR)
  • Increase 1% Per Year
  • Increased Blood Pressure
• Myocardial Cells Replaced by Fatty Infiltration & Amyloid Deposits
  • Left Ventricle Hypertrophy, Thickening & Stiffening
• Resting Left Ventricle Ejection Fraction (LVEF) Not Changed if Healthy
• Increased Prevalence of Premature Atrial Complexes (PAC’s)

Pulmonary Changes

• Loss of Elastic Tissue, Enlarged Alveolar Ducts & Decreased Elastic Recoil
• Decreased Surface Area for Gas Exchange & Increased Anatomic Dead Space
• Decreased Respiratory Drive – Decreased Response to Hypoxemia & Hypercapnia
• Decreased Oxygen Delivery & Consumption
• Decreased Respiratory Muscle & Cough Strength
• Impaired Mucociliary Clearance
• Total Lung Capacity Relatively Unchanged
• Increased Residual Volume
  • Increased Functional Residual Capacity
  • Decreased Vital Capacity

Renal Changes

• Decreased Renal Mass/Size & Number of Glomeruli
  • Can Lose Almost 50% of Functional Glomeruli with Normal Aging Alone
• Decreased Renal Perfusion
  • Vasodilating Prostaglandins May Be Increased at Baseline – Risk for Renal Injury with NSAID’s is Nearly Doubled
• Progressive Glomerulosclerosis
• Fluid & Electrolyte Homeostasis is Relatively Preserved

Neurologic Changes

• Decreased Brain Mass/Volume
  • Greatest in Frontal & Temporal Lobes
  • Hypothalamus, Pons & Medulla Have Minimal Mass Changes
• Increased CSF to Compensate
• Impaired Cerebral Blood Flow Compensation in Response to Blood Pressure Changes
• Impaired Episodic Memory, Working Memory & Executive Function
• Procedural, Primary & Semantic Memory are Generally Well Preserved

Skin Changes

• Skin Atrophy with Thinner Epidermis
• Flattened Dermal-Epidermal Junction (Loss of Undulations) – Increased Fragility to Shear Stress
• Decreased Elasticity

Immune System Changes (Immunosenescence)

• Impaired Ability of Lymphocytes to Generate an Effective Immune Response to New Antigens
• Impaired Regulation of Inflammatory Processes – May Demonstrate a Chronic Low-Level Inflammatory State

Hematopoietic Changes

• Bone Marrow Mass Decreases – Replaced by Fat
• Red Blood Cells:
  • Erythrocyte Volume & Lifespan Remain Unchanged
  • Compensatory Response to Blood Loss & Phlebotomy is Decreased
• White Blood Cells:
  • Total White Blood Cell Counts Remain Unchanged
  • Function May Be Impaired
• Platelets:
  • Total Number of Platelets Remains Unchanged
  • Platelets are Hyper-Responsive to Thrombotic Stimulation
• Increased Age Can Be Considered a Procoagulant State:
  • Clotting Factors Increase
  • Plasminogen Activator Inhibitor 1 (PAI-1) Dramatically Increases

Increased Susceptibility to Adverse Drug Reactions

• Poor Renal Clearance
• Increased Vd
• Polypharmacy
• Increased Sensitivity to CNS Actions
• Low Albumin (High Free Drug Concentrations)