Elderly

Physiological changes associated with aging
Pharmacologic considerations
Patient care and assessment

As the population ages, an increasing number of gastrointestinal endoscopic procedures are being performed on elderly individuals. By definition, geriatric patients are identified as people aged 65 and older, and advanced age patients are individuals aged 80 and older. In the year 2000, the number of people over age 65 made up 12.6% of the total population.  In general, indications for gastrointestinal endoscopy for elderly patients remain the same as for other adults.  Endoscopic procedures may be performed more frequently in this age group due to the development of age-related diseases such as cancer, gastrointestinal ischemia, and biliary tract disease.  In addition, cognitive impairment may impact the ability of the elderly to provide informed consent.

Several studies have found that advanced age itself is not a contraindication for endoscopic procedures.  However, when performing endoscopic procedures on geriatric patients, it is important to realize that additional precautions should be observed. For example, elderly patients may have a reduction in body mass, total body water, and renal and liver function, and the altered volume of distribution can lead to oversedation when narcotics or water soluble agents such as intravenous midazolam are used for sedation.  In addition, elderly individuals are more likely to suffer from chronic illness, further increasing their risk of cardiopulmonary complications. 

Physiological changes associated with aging

The aging process affects all major organ systems. Most data points to aging being caused by reactive oxygen species, byproducts of aerobic metabolism in mitochondria, which create oxidative stress and cell injury. Consequently, organ function declines at the rate of approximately 1% to 1.5% each year after the age of 30. These physiological changes can potentially impact sedation of elderly patients. 

Cardiovascular system 

Physiological differences 

  • Reduced tissue elasticity in arteries and veins
  • Ventricular hypertrophy
  • Reduced cardiac output
  • Reduced arterial oxygenation
  • Deterioration of the cardiac conduction system

Sedation considerations

  • Increased oxygen consumption
  • Inability of the body to adjust to hemodynamic changes
  • Higher likelihood of arrhythmias
  • Slower cardiorespiratory response to hypercarbia and hypoxia

Body composition

Physiological differences

  • Higher proportion of body fat
  • Less intracellular fluid

Sedation considerations

  • Expanded distribution volume for pharmacologic agents
  • Higher risk of oversedation with water-soluble drugs
  • Slower recovery period for lipid-soluble drugs

Pulmonary system

Physiological differences

  • Decreased respiratory drive
  • Less lung capacity

Sedation considerations

  • Decreased ability for the body to compensate for respiratory depression caused by sedative agents
  • Higher incidence of transient apnea

Neurologic system

Physiological differences

  • Loss of neuronal density
  • Reduced levels of neurotransmitters

Sedation considerations

  • Increased sensitivity to CNS depressant drugs
  • Higher incidence of confusion and delirium with sedation

Renal system

Physiological differences

  • Reduced blood flow to the kidneys
  • Decreased glomerular filtration rate

Sedation considerations

  • Increased risk of renal insufficiency
  • Longer duration of action for some anesthetics and adjuvant drugs

Hepatic system

Physiological differences

  • Reduced blood flow to the liver
  • Less liver enzyme activity

Sedation considerations

  • Increased duration of action for lipid-soluble drugs
  • Altered metabolism of drugs

Airway

Physiological differences

  • Diminished gag reflex
  • Loss of teeth and use of dentures
  • Arthritis of the neck

Sedation considerations

  • Increased risk of aspiration
  • Difficulty in mask ventilation
  • Difficulty performing head-tilt, jaw-thrust maneuver of airway

Pharmacologic considerations

The general recommendations for the administration of sedation in geriatric patients are:

  • Use fewer agents at lower doses. Dosing based solely on mg/kg body weight may produce respiratory depression and hypotension. 
  • Deliver agents at a slower rate to allow for assessment of effects at each dose level;
  • Administer a lower cumulative dose of sedative agents.

In addition, the sedative agents chosen for elderly patients should have a short half life, minimal active metabolites, and limited side effects.  Recommendations regarding specific agents include:

  • As with younger adults, midazolam is usually the first choice. It can be combined with an opioid. 
  • Initial doses of sedative-hypnotic agents should be reduced, for example, to half the normal recommended adult dose, and then titrated to effect.
  • Propofol has a narrower margin of safety in elderly patients, but when titrated slowly to effect can be used safely in this age group.

Patient care and assessment

As a vulnerable group, geriatric patients have needs that require particular attention in assessment, monitoring and care.  For example, it is necessary to inquire about advance directives and to not automatically assume that a "do not attempt resuscitation" order has to be suspended when a patient enters the GI suite for endoscopy.

Patient assessment
As with younger patients, a thorough pre-procedure assessment should be preformed prior to the endoscopic procedure. Patient factors that may affect response to sedation and analgesia or present difficulties in airway management must be assessed. With geriatric patients, a careful evaluation of the cardiopulmonary system to uncover evidence of coronary artery disease, hypertension, prior heart attack, or chronic lung disease is especially important.  Consultations with the anesthesiologist or medical specialist should be sought where appropriate. In addition, a thorough review should be performed of the individual's current medications including over-the-counter and herbal supplements.

Thermoregulation
Older individuals do not regulate their body temperature as efficiently as younger adults, therefore they can be subject to hypothermia during procedures. Given an elderly patients' impaired thermoregulation, these patients require additional protection from cold/heat during sedation. Any shivering can result in two to three times higher oxygen consumption. This can be discomforting to the patient and increase cardiovascular stress. 

Monitoring and supplemental oxygen use
Procedural monitoring for geriatric patients should adhere to the standard guidelines in place for moderate sedation. Care should be taken with neck extension in older patients with rheumatoid arthritis because these maneuvers have the potential to produce injury. Supplemental oxygen should be used, especially in patients with compromised cardiovascular or pulmonary function. However, clinicians should be aware of the risk that oxygen dosing has the potential of causing respiratory depression when patients with chronic hypercarbia lose the respiratory drive of hypoxemia.

Physical limitations and psychological well-being
Elderly individuals may have trouble adjusting to the fast-paced, sometimes hectic settings in which endoscopic procedures are preformed. Physical limitations (including movement difficulties and hearing and vision loss) as well as psychological and cognitive changes can lead to frustration and confusion on the part of elderly individuals undergoing procedures.  Clinicians can help reduce these patients' anxiety by being careful to assess the individual's special needs, to speak slowly and clearly, and to provide additional information or support where needed.  Evaluating the patient's physical limitations must be considered for comfortable positioning during endoscopy.

 

 

ASGE Guideline: modifications in endoscopic practice for the elderly. Gastrointestinal Endoscopy. 2006;63(4):566-69.

Kost M. Moderate Sedation/Analgesia: Core Competencies for Practice, 2nd Ed. St. Louis, MO: Saunders, St. Louis; 2004.p.202.

Lazear SE. Course 1055: Moderate sedation/analgesia. CME resources. Revised 01/01//06. http://www.netce.com/coursecontent.php?courseid=338

 


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