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Program Information. Critical Care for Older Adults. Dorothy W. Bird, MD* Lisa B. Caruso, MD, MPH† Suresh Agarwal, MD, FACS* Boston University Medical Center Department of Surgery*, Department of Medicine- Geriatric Services†. Introduction.
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Critical Care for Older Adults Dorothy W. Bird, MD* Lisa B. Caruso, MD, MPH† Suresh Agarwal, MD, FACS* Boston University Medical Center Department of Surgery*, Department of Medicine- Geriatric Services†
Introduction • Older adults (age >65yo) are the fastest growing segment of the US population (ref: 1,2) • Almost HALF of all ICU admissions are older adults (ref: 1,2) • Exacerbation of chronic illness • New onset of illness or trauma • By 2030 20% of Americans will be >65yo (ref: 1) • By 2050 5% of Americans will be >85yo (ref: 1)
Introduction • Older adults differ from their younger ICU counterparts in several ways: • Physiology (cardiopulmonary, renal) • Drug metabolism • Nutritional needs • Susceptibility to delirium • ICU outcomes • Closer to end of life
Cardiovascular Changes • Age-related changes in collagen, elastin→loss of recoil (ref: 3) • Increased systolic blood pressure • Widened pulse pressure (ref: 1) • Progressive left ventricular stiffness, thickness →Diastolic Dysfunction (ref: 1,2,3) • Less able to tolerate atrial fibrillation • Increased sensitivity to volume overload • Increased susceptibility to heart failure • Increased preload dependency
Cardiovascular Changes • Fewercardiacmyocytes(ref:2,4) • Fibrosis/lossofautonomictissue(ref:2) • Conductionabnormalities(sicksinus,a-fib,BBB) • Diminishedsensitivitytoβ-adrenergicstimulation(ref:1,2,3,4) • Strokevolume,preloadmoreimportantforincreasingcardiacoutput • Evenminorhypovolemiacancausecardiacimpairment(Increasedpreloaddependency) • Diminishedresponsetonorepinephrine,isoproterinol,dobutamine
Cardiovascular Risk Factors • Increased prevalence of coronary artery disease in older adults (ref: 1,2,3) • May present as heart failure, pulmonary edema, arrhythmias • Myocardial ischemia more likely to go unrecongnized
Pulmonary Changes • Increased chest rigidity (ref: 1,2,3,4), kyphosis (ref: 2) • Increased work of breathing • Decreased forced total lung capacity, vital capacity, FEV11,3 • Decreased inspiratory, expiratory force (ref: 1,2) • Diminished respiratory muscle strength (↓25%) (ref: 1,4)
Pulmonary Changes • Premature closure of terminal airways (ref: 3) • V-Q mismatch (ref: 2,3) • Decrease in PaO2 controversial (ref: 3,4) • Expected PaO2= 100 – 0.325 x age • Increased A-a gradient (ref: 1,3) • Expected P(A-a)O2 = (age +10) x 0.25
Pulmonary Changes • Blunted Ventilatory control (ref: 2,3) • Diminished response to hypoxia (↓50%) • Diminished response to hypercapnia (↓40%) • Reduced cough, mucociliary clearance (ref: 2,3) • Impaired pulmonary immunity (ref: 2,3) • Diminished gag (ref: 3) • Difficulty swallowing (ref: 2,3) • Increased risk of aspiration
Cardiopulmonary Summary Cardiopulmonary BASICS: • Decreased cardiac and respiratory reserves can lead to rapid decompensation in older adults and slower response time in correction • Pulmonary insult (pneumonia) can trigger heart failure exacerbation • Acute respiratory failure can result from hemodynamic shock
Renal Changes • Decreased creatinine clearance (CC), decreased GFR (ref: 1,2,3) • Cockroft-Gault Estimated CC = (140-age) x wt(kg)/72 x serum creatinine • Adjust medication dosage based on estimated CC, not serum creatinine!
Renal Changes • Concealed renal insufficiency (ref: 2) • Reduced GFR despite NORMAL serum creatinine • May be due to increased prevalence of hypertension, diabetes in elderly • Present in 13.9% of elderly patients • Associated with increased risk of adverse reaction with hydrophilic medications
Renal Changes • Loss of nephrons (0.5-1%/year) (ref: 2,3) • Reduced renal plasma flow (10%/decade) (ref:1,2,3) • Reduced concentrating ability of medullary nephrons (ref: 1,2,3) • Less responsive to ADH (ref: 2,3) • More free water loss→ dehydration, electrolyte imbalance (hyperkalemia, hyponatremia) • Thiazide-induced hyponatremia common in older adults
Nutrition • Protein-calorie malnutrition is common in older adults at admission and may develop quickly during hospitization (ref: 1,2,3) • Diminished muscle mass→ hospital malnutrition→ further weakness (ref: 2,3) • Increased mortality in underweight older adults (ref: 3) • Low albumin, pre-albumin associated with increased post-op mortality in older adults
Nutrition • Assess nutritional status in all older adults: • pre-albumin • transferrin • indirect calorimetry • CRP: marker of inflammation, inverse relationship with pre-albumin • Nutritional support should begin within 24h of ICU admission (ref: 2)
Medications • Adverse drug reaction is the most common iatrogenic disorder in older adults (ref: 3) • Age is an independent risk factor for adverse drug interaction2 • Increased body fat (25-50%), decreased body water in older adults (ref: 1,3) • Hydrophilic drugs (digoxin, theophylline) have lower volume of distribution—reach higher levels faster • Lipophilic drugs (psychotropics) have larger volume of distribution—progressive accumulation • Impaired drug excretion (renal, hepatic) (ref: 3) • EFFECT: increased half-life, longer duration of action of many medications (ref: 3)
Medications • Reducedserumalbumin→higherfreedruglevels→greaterpharmacologiceffect(ref:3) • Decreasedcytochromep450activity→reducedelimination(especiallywarfarin,theophylline)(ref:3) • Alteredsensitivityofreceptorstocommonlyusedmedications(ref:3) • Moresensitive:warfarin,narcotics,sedatives,anticholinergics • Lesssensitive:β-adrenergicagonists/antagonists • Polypharmacy(ref:2,3) • Probabilityofadversedruginteraction: • 7%ifon>5medications,24%ifon>10medications
Medications • Drugs most often associated with adverse reactions (ref: 2): • Digitalis • ACE-I • Hypoglycemics • Contrast-induced nephrotoxicity- increased in older adults (ref: 2) • Ensure preventative measures are taken when using contrast studies! • When starting medications: Start low, go slow! • Especially with sedatives and anti-psychotics!
Delirium • Seen in 1/3-1/2 of hospitalized older adult patients (ref: 2,3) • Up to 70% of older adults in ICU (ref: 2,3) • Can lead to loss of mobility, atrophy, contractures, pressure ulcers, falls, thromboembolism, incontinence, anorexia, constipation, de-motivation (ref: 3) • Associated with prolonged hospitalization, nursing home placement, increased mortality (ref: 2,3)
Delirium • Predisposing factors: (ref: 2,3) • Prior cognitive impairment: patients with dementia are 5x more likely to develop delirium! • Structural brain disease • Chronic illness • Sleep deprivation • Drug/alcohol use • Unfamiliar surroundings/social isolation • Use of sedatives, psychotropics, restraints can worsen symptoms, increase risk of aspiration, ulcers, etc. (ref: 3)
Delirium • Indicative of diffuse brain dysfunction (ref: 3) • Associated with four disease classes: (ref: 2,3) • Primary cerebral disease (infection, tumor, stroke, dementia) • Systemic illness (infection, cardiac, pulmonary, hepatic, uremia, endocrine) • Intoxication (EtOH, drugs, toxins) • Withdrawal (EtOH, benzodiazepine, barbiturates)
Delirium • Prevention,Treatment (ref: 2,3) • Identify underlying cause! • Minimize offending medications • neuroleptics, opioids, anticholinergics, sedatives, H2-blockers • Constant observation, minimize restraints! • Well-lighted, predictable environment • Eyeglasses, hearing aids, dentures • Frequent reorientation by staff and family • Establish normal sleep-wake cycle
Postoperative Cognitive Dysfuntion(POCD) • Acute, short-term disorder of cognition, memory, attention following surgery (ref: 2) • Present in 26% non-cardiac surgery older adults at 1 week post-op, 9.9% at 3 months (ref: 2) • Present in 80% of older adults after cardiac surgery by discharge, 50% at 6 weeks post-op (ref: 2) • May be first sign of hypoxemia, sepsis, electrolyte imbalance! Usually idiopathic (ref: 2) • Suspected interaction between anesthesia and age-related change in neurotransmitters (ref: 2)
POCD • Prognosis • Good: transient symptoms in most sufferers (ref: 2) • Prolonged POCD: may last months→ years (ref: 2) • Risk factors • AGE! (ref: 2) • Also: duration of anesthesia, post-op infection, respiratory complicaions (ref: 2) • Age is the only risk factor for prolonged POCD (ref: 2)
Pressure Ulcers • Associated with immobility in older adults • 50% pressure ulcers occur in those >70yo (ref: 3) • Sites: • sacrum, ischial tuberosities, hip, heel, elbow, knee, ankle, occiput • Found in 28% of those confined to bed or chair for 1 week (ref: 3) • High mortality • 73% mortality if develops in first 2 weeks of hospitalization (ref: 3) • May lead to sepsis→ 60% mortality if ulcer is cause (ref: 3) • Now considered a “never event”- no reimbursement
Pressure Ulcers • Prevention • Frequent repositioning: q2 hours (ref. 3) • Avoid pressure on bony prominences (ref. 3) • Rest back on pillows at 30-degree angle from bed • Head of bed not more than 30 degrees (ref. 3) • Do not tuck sheets at foot of bed (ref. 3) • Allow feet to assume natural position • Protect heels by elevating feet with pillows • Lift patients to move, do not drag (ref. 3) • Pat skin dry, do not rub (ref. 3) • Reduce contact with soilage (fecal, urinary incontinence) (ref. 3)
Pressure Ulcers • Prevention • Ensure adequate nutrition, hydration, pain control (ref. 3) • Early mobilization (ref. 3) • Rehab service consult (ref. 3)
Outcomes • Age is associated with progressive risk of ICU death2 • Mortality: 36.8% in >65yo; 14.8% <45yo (ref. 2) • 1-year post-ICU survival: 47% in ≥65yo, 83% <35yo (ref. 2)
Outcomes • Octegenarian hospital survivors discharged to subacute facility have higher mortality compared to those discharged to home (31% vs. 17%) (ref. 2) • Likelihood of discharge to subacute facility directly related to preadmission comorbidities (ref. 2)
Optimizing ICU Use GOAL: Minimize misery, maximize dignity • ICU care should provide temporary physiologic support for reversible conditions (ref. 2) • Decision to admit older adults should be based on: patient comorbidities, acuity of illness, prior functional status, patient’s wishes (ref. 2) • Always clarify and document advanced directives and wishes for intubation, CPR, vasoactive medication
References 1. Nagappan R, Parkin G. Geriatric critical care. Crit Care Clin 2003:253-270. 2. Marik, PE. Management of the critically ill geriatric patient. Crit Care Med 2006; 34(9):S176-S182. 3. Dhanani S, Norman DC. Chapter 19. Care of the elderly patient. In: Bongard FS. Current diagnosis and treatment critical care. 3rd ed. New York: McGraw-Hill;2008. 4. Delerme, A, Ray P. Acute respiratory failure in the elderly: diagnosis and prognosis. Age and Aging 2008;37:251-257.