Ebook Millers textbook (8/E): Part 5
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Ebook Millers textbook (8/E): Part 5
Chapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5e in all organ systems, with considerable variation from person to person.•Older patients are more sensitive to anesthetic drugs. Less medication is usually required to achieve a desired clinical effect, and drug effects are often prolonged. Hemodynamic responses to intravenous anesthetics may be ex Ebook Millers textbook (8/E): Part 5aggerated because of interactions with the aging heart and vasculature.•The incidence of postoperative delirium is substantially more frequent in patiEbook Millers textbook (8/E): Part 5
ents svith preoperative dementia.•The ability to predict patients at high risk for postoperative delirium has enabled proactive interventions to preveChapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5predisposing or precipitating factors for delirium.•Postoperative cognitive dysfunction (POCD) in older patients occurs in the first days to weeks after surgery. POCD is well documented, and early POCD is reversible.•Perioperative management of depression is a lower priority than management of the p Ebook Millers textbook (8/E): Part 5atient's more acute medical illnesses.•Although advance directives can be helpful in perioperative decision making, accurate documentation of advanceEbook Millers textbook (8/E): Part 5
care planning is often lacking for many older patients.•In older patients perioperative complications lead to poor outcome. The most important risk faChapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5iologists class), whether the surgery Is elective or urgent, and the type of procedure.•The success of surgical intervention in geriatric patients depends partly on whether patients can return to their previous level of activity and independence.•Recognizing acute illness and exacerbation of chronic Ebook Millers textbook (8/E): Part 5 disease in older adults can be challenging. Not infrequently, acute illness may have an atypical presentation.Defining and implementing optimal perioEbook Millers textbook (8/E): Part 5
perative care for older adults is of increasing importance to all stakeholders in health care, including consumers, insurers, and government agencies.Chapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5r patients. The demographic considerations are sobering. The U.S. Census 2010 data revealed the number of persons older than 65 years of age in the United States had increased to 40.4 million, with 21.7 million 65 to 74 years old, and 13.1 million 75 to 84 years of age, with 5.5 million over the age Ebook Millers textbook (8/E): Part 5 of 85 years, the average life expectancy was 78.2 years. It is estimatedthat by 2030, 20% of U.S. citizens will be older than 65 years. By 2034, babyEbook Millers textbook (8/E): Part 5
boomers in the United States will all be over 70 years of age. By 2050 those over 85 years of age will represent 14% of the population over 65 years.Chapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5d roughly 12% of the U.S. population, accounted for one third of all hospitalizations and 43.6% of inpatient hospital charges.1 Patients 65 years of age and older have surgery at a rate 2 to 3 times that of younger patients and tend to have longer hospital stays.424072408 PART V: Adult Subspecialty Ebook Millers textbook (8/E): Part 5ManagementCORE CONCEPTS IN THE ANESTHETIC MANAGEMENT OF THE OLDER PATIENTTwo important principles must be kept in mind when discussing the physiologyEbook Millers textbook (8/E): Part 5
of aging. First, aging is associated with a progressive loss of functional reserve in all organ systems. Second, the extent and onset of these changesChapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5ogic reserve may become evident only during times of physiologic stress, including exercise, illness, and surgery. Anticipating the interaction of underlying disease, limited end-organ reserve, and the stress of the perioperative period should aid the perioperative physician in providing the best ca Ebook Millers textbook (8/E): Part 5re possible.MECHANISMS OF AGINGAging is a universal and progressive physiologic process characterized by declining end-organ reserve, decreased functiEbook Millers textbook (8/E): Part 5
onal capacity, increasing imbalance of homeostatic mechanisms, and an increasing incidence of pathologic processes? Aging is now viewed as an extremelChapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5ategories including evolutionary and physiologic mechanisms. These may also be defined according to the “programmed" or biologic clock theory, in which genetic mechanisms program declining function, and “error" theories, in which environmental damage to processes lead to impaired function and progre Ebook Millers textbook (8/E): Part 5ssive decline. These processes of aging overlap and may be further defined by the organizational level of an organism in which a given process occurs.Ebook Millers textbook (8/E): Part 5
Changes at one level influence processes at another level. Molecular effects willinfluence cellular function, which in turn causes alterations in majChapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5e are summarized in Table 80-1.CENTRAL NERVOUS SYSTEMWith aging, several important processes occur that are of interest to the anesthesiologist? These changes may be further modified by other underlying pathologic or age-related processes? Memory decline occurs in more than 40% of persons over 60 ye Ebook Millers textbook (8/E): Part 5ars of age but is not a universal finding.10 Importantly, age-related memory decline can dramatically affect performance of the activities of daily liEbook Millers textbook (8/E): Part 5
ving (ADL).Structurally, a decrease occurs in the volume of both gray matter and white matter in the central nervous system (CNS).11 Regions of the brChapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5uronal loss. A small overall loss occurs of neurons from the neocortex.8 This decrease in neuron number is not as massive as older studies had indicated. Some neocortical areas do not lose any neurons with aging. There may be 15% loss, however, of white matter with aging? These structural changes re Ebook Millers textbook (8/E): Part 5sult in gyral atrophy and increased ventricular size. Shrinkage in the subcortical white matter and hippocampus may be accelerated by hypertension andEbook Millers textbook (8/E): Part 5
vascular disease.Whether the aging process alters the number of synapses present in the cortex is controversial. Data from nonhuman primates suggest Chapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5 primary neurotransmitter in the cortex.TABLE 80 1 CLASSIFICATION AND BRIEF DESCRIPTION OF THEORIES OF AGINGBiologic level and Theory Evolutionary Mutation accumulation Disposable somaDescription Mutations that affect health at older ages are not selected against Somatic cells are maintained only to Ebook Millers textbook (8/E): Part 5 ensure continued reproductive success; after reproduction, soma becomes disposableAntagonistic pleiotropy Molecular Gene regulation Codon restrictionEbook Millers textbook (8/E): Part 5
Genes beneficial at younger age become deleterious at older age Aging is caused by changes in the expression of genes regulating both development and Chapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5Cellular Senescence-telomere theoryDecline in fidelity of gene expression with aging results in increased fraction of abnormal proteins Molecular damage accumulates primarily to DNAand generic material Gradual accumulation of random molecular damage Impairs regulation of gene expression Phenotypes o Ebook Millers textbook (8/E): Part 5f aging are caused by an increase in frequency of senescent cells as a result of telomere loss or cell stressFree radical Wear-and-tear Apoptosis SystEbook Millers textbook (8/E): Part 5
em Neuroendocrine Immunologic Rate-of-livingDamage caused by free radical production from oxidative metabolism Accumulation of normal injury ProgrammeChapter 80Geriatric AnesthesiaFREDERICK SIEBER • RONALD PAULDINEKey Points•An important principle of aging is a progressive loss of functional reserve Ebook Millers textbook (8/E): Part 5 infection and autoimmunity Assumes a fixed amount of metabolic potential for every living organism (live fast, die young)Modfied from Weinert tfĩ. ĨẲtnlraỊ PS- Invited review: theorieĩ of 0Ci>rv! J Appt Physiol f>5; 1707, 200Ì. With permnwnare not affected. Coupling of cerebral electrical activity, Ebook Millers textbook (8/E): Part 5 cerebral metabolic rate, and cerebral blood flow remains intact in older individuals.Although biochemical and anatomicchanges have been descrilxxl inEbook Millers textbook (8/E): Part 5
the aging brain, the exalt mechanisms causing change?* in functional reserve are unclear. Decreases in brain reserve manifest by decreases in functioGọi ngay
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