As a paramedic, you are called to see an 89 year old woman who lives alone, and is complaining of dyspnea. Her daughter states the patient hasn't been feeling well, has had nothing to eat or drink for 2 days, and has been confined to bed. Today, she became short of breath, which has been worsening for the last 3 hours. She has a history of myocardial infarction and congestive heart failure, and has been prescribed several medications including digoxin, lisinopril, isosorbide, and furosemide. On exam, she is somnolent and in mild respiratory distress, with blood pressure of 70/40 and irregular pulse of 104. Rales are present 1/4 of the way up her lung fields, and there is 1+ ankle edema. A quick look with the paddles shows sinus tachycardia with frequent premature ventricular beats. You place an IV line and oxygen, and transport her to the emergency room.

Q: Which of the following are potentially important to her presentation and care?

• Myocardial ischemia
• Intravascular volume depletion
• Decreased creatinine clearance
• Decreased cardiac output
• Decreased renal blood flow

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Q: If she has a ventricular fibrillation arrest on the way to the E.R., and is successfully resuscitated to sinus rhythm, what considerations are important in giving lidocaine?

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Changes in Physiology with Aging

• Decreased Homeostasis is a Hallmark of Aging.
• Older people may exhibit no changes in baseline function, but may have decreased ability to adapt to stress:
  • Example: Fasting blood glucose levels show little change with normal aging, but even apparently normal older people have more hyperglycemia after glucose challenge compared to young adults.
• Various body systems lose reserve capacity with aging at different rates:
  • Gastrointestinal tract, liver: tend to have substantial reserve capacity in absence of disease or self-abuse (e.g., alcoholism)
  • Heart, lungs, brain: may exhibit more advanced functional impairment with aging, especially if damaged by disease, abuse

Changes in Cardiovascular Physiology with Aging

• Changes in cardiac output (CO):
  • Early studies reported decreased CO (Stroke Volume X Heart Rate) at rest
  • However, other studies have found there is no change in CO when patients with occult coronary excluded
  • Maximal heart rate decreased with aging (max. heart rate = 220 - age)
  • Increased end-diastolic and end-systolic left ventricular volumes
  • Thus CO during maximal exercise is maintained by Frank-Starling mechanism
  • Increased force of contraction with increased end-diastolic length of cardiac muscle allows stroke volume to increase, to compensate for lower maximal heart rate
• Diastolic dysfunction
  • Decreased early diastolic filling
  • Increased reliance on atrial contraction
  • Increased vulnerability to congestive heart failure, especially with atrial fibrillation
• Decreased compliance of peripheral blood vessels
  • predisposes to systolic hypertension, left ventricular hypertrophy of heart
• Increased incidence of atherosclerotic cardiovascular disease
• Increased incidence of degeneration of cardiac conduction system

Changes in Pulmonary Physiology with Aging

• Decreased elasticity
  • Decreased vital capacity
  • Increased residual volume
• Decreased structural support for small airways
  • Decreased number of small airways open during normal breathing
  • Increased risk of atelectasis, pneumonia

   

Changes in Renal/Fluid/Electrolytes with Aging

• Decreased glomerular filtration rate, renal blood flow, creatinine clearance (variable)
• No change in baseline serum sodium and potassium concentrations or blood pH
• Decreased adaptive mechanisms:
  • Decreased response to sodium restriction
  • Decreased salt conservation
  • Increased risk of volume depletion
  • Decreased excretion of sodium load related to decreased glomerular filtration rate and decreased baroreflex sensitivity
  • Increased risk volume overload with saline
• Decreased free water conservation
  • Decreased maximal urine concentration
• Decreased sense of thirst
• Functional impairment may lead to decreased access to water, in turn leading to increased risk of hypovolemia, hypertonic dehydration:
  • see Case Presentation for example
• Water intoxication more common:
  • relative excess of antidiuretic hormone (ADH) with aging
  • overt syndrome of inappropriate ADH secretion is common in older adults
  • Contributors:
    • medications (sulfonylureas, diuretics)
    • alcohol ingestion
    • medical problems
    • congestive heart failure, hypothyroidism, central nervous system conditions
  • may lead to severe hyponatremia with altered mental status in some patients
• Alterations in renal potassium handling 
  • Increased risk of hyperkalemia due to decreased glomerular filtration rate and decreased aldosterone
  • Diabetics: markedly increased risk of hyperkalemia
  • Contributors:
    • type IV renal tubular acidosis with hyporeninemic hypoaldosteronism as renal function declines
    • medications (Potassium supplements, Angiotensin-converting enzyme inhibitors, Non-steroidal anti-inflammatory drugs, Potassium-sparing diuretics (aldosterone antagonists, including spironolactone, triamterene)

Changes in Vision and Hearing with Aging

• Significant visual, hearing impairment is present in up to 75% of elderly people
  • These problems are often not reported to the physician
  • May limit ability to function
  • May lead to social isolation
  • May interfere with ability to communicate
  • patients with sensory impairments may appear demented
• Approach to Visual/Hearing-Impaired Older People
  • Reduce extraneous noise
  • Speak slowly, in deep tones
  • Face the person so s/he can see your lips
  • Provide adequate lighting if possible
  • Use a "Pocket Talker" (portable amplifier with headphones, used as a hearing aid)
  • Allow adequate time to respond
  • Don't "talk down" (speak in a condescending or exaggeratedly simplistic manner) this is hearing/visual impairment, NOT intellectual impairment!

   

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Disclaimer

Copyright 1999, 2000 David A. Gruenewald, M.D. and
Kayla I. Brodkin, M.D. All rights reserved.