Geratric 9-15 Flashcards
- What are the disturbances in cardiac rhythm, associated with the elderly?
Cardiac Rhythm disturbances associated with the geriatric population - Due to increased vagal tone & decreased sensitivity of the adrenergic receptors leads to a decline in heart rate (prone for bradycardia); Fibrosis of the conduction system & loss of SA node cells increase the incidence of A-fib & A-flutter. Otherwise in a well-conditioned & otherwise healthy geriatric patient cardiac function is preserved.
- Why is hepatic clearance of drugs decreased in the elderly?
Hepatic clearance in the elderly is decreased due to a decline in liver mass with a corresponding decrease in blood flow. Also age related loss of the endoplasmic reticulum results in decreased protein synthesis (albumin). Thus serum levels of protein-bound drugs increase.
- What renal changes are associated with advanced aging?
Aging had a profound effect on the renal vasculature and therefore exerts great influence in renal function. The glomerular filtration rate decreases approximately 6-8% per decade. Although the ability to concentrate urine and conserve water is progressively impaired, reduction in plasma flow is the primary source of loss of renal function with age. Renal blood flow decreases 1-2% each year after the age of 25 and is decreased 40-50% by the age of 65. Declines in renal blood flow are due to decreases in cardiac output that accompany aging, as well as the reductions in the size of the renal vascular bed.
- How do changes in renal function affect anesthetic management?
The combination of decreased renal and reduced cardiac function makes geriatric patients prone to fluid overload. In addition, renal elimination of drugs may be impaired.
- Why is intra-op temperature difficult to control in the elderly?
Basal metabolic rate decreases with aging, elderly surgical patients may have difficulty maintaining normothermia. Hypothermia may lead to slower metabolism and excretion of drugs and shivering which may cause increased BMR and 02 consumption.
- Do anesthetic requirements increase or decrease in the elderly?
Volatile anesthestics- MAC reduced by 6% per year after the age of 40. Recovery may be prolonged due to increased body fat and decreased pulmonary gas exchange.
IV induction drugs-Small decreases in initial dose, decreased maintenance infusion
Opiods-Decrease initial dose, increased risk for skeletal muscle rigidity, increased duration of systemic and neuraxial effects, increased incidence of depression of ventilation
Locals-Small decreases in dose requirements-expect prolonged effects
Benzos-Decrease in initial dose, expect marked increase in duration of action
Atropine-Increased dose needed for comparable heart rate response, anticipate possible anticholinergic syndrome
- Are the elderly more at risk for aspiration?
Yes. Gradual tissue degeneration is the main cause for respiratory system aging. Protective reflexes, especially coughing and swallowing are diminished with increasing age.
