Ppt Kardiorespirasi.pptx

Physiologic Changes of Aging

Buku doger

• Age-related changes in cardiovascular tissue can be found in cardiac contractile fibers, conducting tissue, and valvular structure

Cardiovascular Physiology • The purpose of the heart is to pump blood rich with oxygen to body tissues. • Cardiac output (CO), or the volume of blood pumped to body tissues each minute, depends on the frequency of cardiac contractions (heart rate, HR) and the volume of blood ejected with each contraction (stroke volume, SV). CO = SV x HR • ventricular filling (preload), ventricular contractility and peripheral vascular resistance (afterload). Ventricular filling occurs early during diastole and is rapid and mostly passive, with the last part of filling attributed to atrial contractions.

AGE-RELATED CARDIOVASCULAR CHANGES AND EXERCISE • Maximal oxygen consumption [V~(max)l, a measure of total body oxygen intake at exhaustion and an index of overall cardiovascular and pulmonary fitness, tends to decrease with aging

• Elderly individuals who exercise regularly and maintain an active lifestyle show less of a decrease in V02(max )

Pulmo

PULMONARY PHYSIOLOGY • The primary functions of the pulmonary system are to exchange gas between the blood and atmospheric air and to protect the body from airborne invaders • Resting lung function results from a balance of elastic tissue forces pulling inward and musculoskeletal pump forces pulling outward. This dynamic and mostly involuntary interplay between lung tissue and chest wall musculoskeletal components depends on the compliance of both

Buku brocklehurts • Advanced age is a major risk factor for the development of cardiovascular disease. • The increased risk might arise simply because there is more time to be exposed to risk factors such as hypertension, smoking, and dyslipidemia. In other words, the aging process itself has little impact on the cardiovascular system. • the accumulation of cellular and subcellular deficits in the aging heart and blood vessels renders the cardiovascular system susceptible to the effects of cardiovascular diseases.

Key points • The structure and function of the human heart and vasculature change as a function of the normal aging process. • The ageassociated increase in stiffness of central elastic arteries promotes systolic hypertension in older adults. • Diastolic dysfunction in the aging heart arises from impaired left ventricular filling, increased afterload, and prolonged availability of intracellular calcium. • Decreased responsiveness to β-adrenergic receptor stimulation limits the increase in heart rate and contractility in response to exercise in older adults. • Despite limits on the ability of the aging cardiovascular system to respond to exercise, regular exercise attenuates the adverse effects of aging on the heart and vasculature and protects against the development of cardiovascular disease in older adult

Age-Related Changes in the Respiratory System  breathing parameters • Forced expiratory volume in 1 second (liters): FEV1. This is the volume of air expired during the first second of a forced expiratory maneuver from vital capacity (maximal inspiration). Measured by spirometry. • Forced vital capacity (liters): FVC. This is the total volume of air expired during forced expiration from the end of maximum inspiration. A slow vital capacity (SVC) is the volume of air expired, but this time through an unforced maneuver. In the young these are similar but in emphysema, where there is loss of elastic recoil, FVC may fall disproportionately more than SVC. These are also measured by spirometry. • Peak expiratory flow rate (liters/minute): PEFR. This is the maximal expiratory flow rate measured using a peak flow meter, a more portable method; therefore serial home measurements may be requested in patients

• The following measurements require more detailed lung function testing: • Total lung capacity (liters): TLC. The volume of air contained in the lung at the end of maximal inspiration. Measured by helium dilution or body plethysmography together with the next two tests. • Functional residual capacity (liters): FRC. This is the amount of air left in the lungs after a tidal breath out and indicates the amount of air that stays in the lungs during normal breathing. • Residual volume (liters): RV. The amount of air left in the lungs after a maximal exhalation. Not all the air within the lungs can ever be expired. • Transfer factor (mmol/minute): TLCO. This is a measure of the ability of the lung to oxygenate hemoglobin. It is usually measured with a single breath hold technique using low concentration carbon monoxide. • Transfer coefficient (mmol/minute/k/Pa/LBTPS): KCO. This is the TLCO corrected for the lung volume

• The obstructive pattern, as seen in patients with asthma and COPD, is characterized by: • Reduced FEV1 and PEFR • Normal or reduced FVC. (If FVC reduced, disproportionately less reduced than FEV1) • Reduced FEV1/FVC ratio to less than 0.7 The restrictive pattern is characterized by: • Reduced FEV1 • Reduced FVC • Normal or high FEV1/FVC ratio

• in addition, blood gas measurements are often performed to assess both acid-base balance and oxygenation. The most important measures for respiratory disease are the partial pressure of oxygen (Pao2), partial pressure of carbon dioxide (Paco2), and the pH. A low Pao2 (hypoxemia) with a normal Paco2 indicates type I respiratory failure. An increased Paco2 with hypoxemia indicates type II respiratory failure.

Key points • • There are both age-related changes and true aging changes in the respiratory system. • Most of the available information comes from crosssectional studies rather than longitudinal studies. • There are structural and functional changes to the lung in the elderly. In addition, there are alterations to respiratory control and immunologic alterations that can all contribute to age-related changes of the respiratory system. Such alterations may be synergistic. • Exercise exerts additional demands on the respiratory system that may reveal respiratory limitation. In addition, although alterations in the respiratory system may not be apparent in the healthy elderly person, acute illness may unearth the diminished respiratory reserve. • Elderly people are less able to perceive bronchoconstriction and other symptoms. In parallel, there is thus relative underreporting of symptoms.

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