Tiêu đề NCM 114 MIDTERMS RLE ✅

NCM 114 MIDTERMS BY TONS and MADS IV and Drug computations with gerontologic considerations Drug Dosage Calculations - required when the amount of medication ordered (or desired) is different from what is available on hand for the nurse to administer. DRUG THERAPY IN THE ELDERLY PHYSIOLOGIC CHANGES AFFECTING DRUG ACTION As a person ages, gradual changes occur in human physiology. Age-related changes may alter therapeutic and toxic effects of drugs. I. BODY COMPOSITION A. Proportions of fat, lean tissue and water in the body change with age. B. Total body mass and lean body mass decrease. C. proportion of body fat increase. D. Affect relationship between drug’s concentration and solubility in the body. E. Water-soluble drug (gentamicin) - not distributed to fat. 1. Less lean tissue → more drug remains in the blood, → toxic levels can result. F. Pentobarbital - distributed to fat; produce lower levels. II. GASTROINTESTINAL FUNCTION A. Decrease gastric acid secretion and GI motility → slow emptying of stomach contents and movement of intestinal contents through entire tract B. More difficulty absorbing medications - significant problem with drugs having narrow therapeutic range (digoxin) in which any change in absorption can be crucial. III. HEPATIC FUNCTION A. Liver’s ability to metabolize certain drugs decreases due to diminished blood flow to the liver ( age-related decrease in cardiac outplut) B. Medications (esp secobarbital): liver reduced ability to metabolize drug → hangover effect due to CNS depression. C. Elimination of these medications is highly dependent on the liver. D. Decreased hepatic function may cause: 1. More intense drug effects due to higher blood levels 2. Longer-lasting drug effects due to: Prolonged blood concentrations 3. Greater incidence of drug toxicity IV. RENAL FUNCTION A. Most elderly persons’ renal function is usually sufficient to eliminate excess body fluid and waste. However, ability to eliminate some medications reduced >50% B. Many medications (ex. digoxin) excreted primarily through kidneys. 1. Kidney’s ability to excrete decreased → high blood concentrations → Digoxin toxicity (anorexia, nausea and vomiting) C. Drug dosages - modified to compensate for age-related decreases in renal function. 1. Laboratory tests: BUN and serum creatinine, to provide expected therapeutic benefits without the risk of toxicity. V. ADVERSE DRUG REACTIONS A. Elderly - twice as many adverse drug reactions from greater drug consumption, poor compliance and physiologic changes. B. S/S: confusion, weakness lethargy; often mistakenly attributed to senility or disease. C. Most of serious reactions in the elderly: diuretics, digoxin, corticosteroids, sleep medications and nonprescription drugs. D. Diuretic toxicity 1. Total body water decreases with age 2. Normal doses of potassium wasting diuretics (hydrochlorothiazide and furosemide) result in fluid loss and dehydration 3. Deplete serum potassium → weakness, raise blood uric acid and glucose levels, complicating pre-existing gout and diabetes mellitus. E. Digoxin toxicity 1

NCM 114 MIDTERMS BY TONS and MADS ● Dehydration, constipation, and malnutrition may occur ● Decrease in subcutaneous fat → more susceptible to temperature changes ● Critical Factors: ○ Skillful preop assessment and treatment ○ Skillful anesthesia and surgery ○ Meticulous and competent post op and post anesthesia management Gerontologic Considerations INTRAOP (OA=older adult)- from 112 book ➢ 1⁄3 of surgical pt are 65 yrs of age or older. ➢ Higher risk for complications from anesthesia and surgery compared w/ younger adult pt due to several factors. ➢ Progressive loss of skeletal muscle mass in conjunction w/ ↑adipose tissue. ➢ Comorbidities, advanced systemic disease, and increased susceptibility to illness, even in the healthiest OA, can complicate perioperative management. ➢ Biologic variations of particular importance: age-related cardiovascular and pulmonary changes. ○ aging heart and blood vessels = ↓ ability to respond to stress. ○ ↓ cardiac output and limited cardiac reserve = vulnerable to changes in circulating volume and blood O2 levels. ➢ Excessive or rapid administration of IV solutions = pulmonary edema. ➢ Sudden or prolonged decline in BP = cerebral ischemia, thrombosis, embolism, infarction, and anoxia. ➢ ↓ gas exchange = cerebral hypoxia ➢ Lower doses of anesthetic agents due to ↓tissue elasticity (lung and cardiovascular systems) and ↓lean tissue mass. ○ ↓plasma proteins → more anesthetic agent remains free or unbound →more potent action ➢ ↑ duration of clinical effects of medications. ➢ Body tissues of OA - made up predominantly of water, and those tissues with a rich blood supply: skeletal muscle, liver, and kidneys, shrink as the body ages. ➢ Reduced liver size →↓rate the liver can inactivate many anesthetic agents ➢ ↓kidney function slows elimination of waste products and anesthetic agents. ➢ Other factors that affect elderly in intraop period: ○ Impaired ability to ↑metabolic rate and impaired thermoregulatory mechanisms → ↑susceptibility to hypothermia. ○ Bone loss (25% W, 12% M): careful manipulation and positioning during surgery. ○ ↓ability to adjust rapidly to emotional and physical stress influences surgical outcomes and requires meticulous observation of vital functions. ➢ Perioperative mortality and morbidity in OA pt ➢ Nursing management for elderly intraop: ○ Application of intraop warming techniques to reduce unintentional hypothermia. ○ Careful transfer and positioning on the OR bed. ○ Protect pressure points and bony prominences with extra padding. ○ Support back and neck to prevent stiffness while maintaining respiratory and circulatory support. ○ Use of antiembolic stockings or sequential compression device to prevent VTE formation. ○ Careful fluid & electrolyte monitoring via accurate blood loss measurement, urinary output, and blood gasses ➢ ↓skeletal muscle mass ↑ adipose tissue ➢ Age - clinical predictor of CV complications ➢ ↓heart and blood vessels ability to respond to stress ↓ cardiac output and limited cardiac reserve → ↑ susceptibility to changes in circulating volume and blood oxygen levels ➢ Sudden/ prolonged decline in BP → cerebral ischemia, thrombosis, embolism, infarction, anoxia ➢ Reduced gas exchange → cerebral hypoxia ➢ Reduced liver size → decreased rate at which liver can inactivate anesthetic agents Decreased kidney function → slow elimination of waste products & anesthetic agents Gerontologic Considerations POSTOP (OA=older adult)- from 112 book ➢ Older pt, transferred from OR table to bed or stretcher slowly and gently. ○ effects of action on BP & ventilation monitored. ➢ Keeping pt warm, (more susceptible to hypothermia) ➢ pt position is changed frequently to stimulate respirations, promote circulation & comfort. ➢ Immediate postoperative care, additional support is given if cardiovascular, pulmonary, or renal function is impaired. ➢ Careful monitoring, possible to detect cardiopulmonary deficits before s/sx are apparent. ➢ Changes associated w/ aging process: prevalence of chronic diseases, alteration in fluid and nutrition status, and ↑ use of medications = need for postop vigilance. ➢ Slower recovery from anesthesia due to prolonged time it takes to eliminate sedatives and anesthetic agents. ➢ Postoperative confusion and delirium may occur in up to half of all older patients. ○ Pain, altered pharmacokinetics of analgesic agents, hypotension, fever, hypoglycemia, fluid loss, fecal impaction, urinary retention, or anemia= Acute confusion ➢ Providing adequate hydration, reorienting to environment, and reassessing doses of sedative, anesthetic, and analgesic agents may reduce risk of confusion. ➢ Hypoxia: confusion and restlessness, as can blood loss and electrolyte imbalances. ➢ confusion is r/t age, circumstances, and medications. ➢ Dehydration, constipation, and malnutrition may occur postoperatively. 3