Review article: Age related alterations in respiratory function — anesthetic considerations

Abstract

This review examines the effect of aging on pulmonary reserve. Special emphasis is placed on how anesthetic and surgical factors may impose substantial stresses on the respiratory system of elderly patients, leading to increased risk for postoperative pulmonary complications including respiratory failure. A MEDLINE-based English-language literature search was undertaken for the period 1966-2006, and an EMBASE search covered the overlapping period 1988-2006. Selected articles were limited to those applying to elderly subjects/patients. Age-related loss of the lung static recoil forces, stiffening of the chest wall and diminished alveolar surface area lead to a decrease in vital capacity, an increase in residual volume, decrease in expiratory flows and increased ventilation-perfusion heterogeneity. Respiratory muscle strength consistently declines with age further increasing the work of breathing. While gas exchange may be well preserved at rest and during exertion, pulmonary reserve is diminished, and under conditions of positive fluid balance, positioning for surgery, and increased metabolic demand, postoperative respiratory failure can occur. Increased sensitivity to respiratory depressants and muscle weakness pose additional risks for the development of postoperative respiratory complications in elderly patients. Regional anesthetic techniques provide for superior postoperative analgesia, without necessarily altering the frequency of postoperative pulmonary complications in the older surgical population. Alterations in respiratory physiology associated with aging must be appreciated to anticipate and minimize potential complications associated with surgery and anesthesia in the elderly. Individualized care to optimize preoperative cardiorespiratory function, minimize intraoperative respiratory pertubations, and to gently restore postoperative pulmonary function are essential anesthetic goals for elderly patients who require surgery.