HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:
Guest Access | Sign In via User Name/Password

This Article Abstract Full Text (PDF) Free Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Oskvig, R. M. Search for Related Content PubMed PubMed Citation Articles by Oskvig, R. M.

Special Problems in the Elderly^*

^* From the University of Rochester Medical Center, Rochester, NY.

Correspondence to: Roger M. Oskvig, MD, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642

	Abstract

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
With aging, the heart, kidneys, liver, lungs, and brain lose mass. While not inherently impaired, the reserve capacity of the older individual to compensate for stress, metabolic derangement, and drug metabolism is increasingly limited. Functional disability occurs faster and takes longer to remediate, necessitating early preventive interventions.

	Introduction

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
Life expectancy has nearly doubled since the beginning of the 20th century. The population over the age of 65 years is growing at the fastest rate of any age group, and the fastest growing segment of all is the group aged 85 years and older. Those > 65 years constitute 14% of the population and will account for > 20% in the next half century.¹ The gender difference in longevity results in a male to female ratio of 39 to 100 by the age of 85 years, and the ratio shrinks progressively thereafter.² Currently, one in four surgical patients is > 65 years, and half of individuals > 65 years will have an operation in the remainder of their lifetime.³ Better understanding and use of perioperative monitoring, earlier interventions, earlier mobility and return to usual activity, and neuroleptic anesthesia have all contributed to lower surgical mortality.⁴ With a progressively aging population, the aspects of perioperative care of the geriatric patient will increase correspondingly in relevance.

Cardiac, pulmonary, nutritional, hematologic, and renal issues in medical care are described by the functional aspects of the organ system or physiology involved. In contrast, there is no consensus on what defines a medical issue as geriatric. Even with increasing sophistication in understanding the biology of aging, such as phosphorylation of protein, amyloid proteins, and terminal transcriptase, there is no clinical marker of the "geriatric" patient. However, there is consensus that physical and medical heterogeneity increases as the population gets older; that is, this population is unique for its nonhomogeneity.

Nevertheless, if the commonly held standard of 65 years old is used, some important observations can be made. Approximately one eighth of this group use two thirds of medical resources each year. The elderly use a disproportionate amount of the medications prescribed.⁵ Age itself is an independent morbidity and mortality risk for a long list of diseases and injuries, hospitalization, length of hospitalization, and adverse drug reactions.⁶ Medical literature is informative, but predominantly cross-sectional rather than longitudinal, confounding interpretation of which changes can be attributed to age alone. Whatever the cause, however much the heterogeneity, what will be reviewed will show that cardiopulmonary, hepatic, renal, and nervous system reserves are reduced in the elderly and susceptible to decompensation.

	The Aging Respiratory System

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
No substantial literature of longitudinal studies of changes in the respiratory system exists, yet age-related changes in structure and function have been clearly established by cross-sectional studies.⁷ Neither rounding of the thoracic cage nor the increase in dead space from enlargement of the cartilaginous conducting airways are thought to have significant functional significance.^{7 8} Total lung capacity either does not decline with age or declines very slowly.⁷ Decrease in lung compliance with aging is not physiologically significant.⁹ As a matter of fact, the elastin content of the lung is very stable, turning over very little with age.¹⁰ Resting oxygen uptake, and right atrial, pulmonary artery, and pulmonary capillary wedge pressures are unchanged even in the oldest asymptomatic individuals.¹¹

The changing shape of the chest wall may be functionally unimportant, but the rigidity of the chest wall with aging has measurably negative mechanical implications.^{12 13} A 70-year-old man expends 70% of the total elastic work of breathing on the chest wall compared with 40% for a 20-year-old. While there is great variation between individual and genders, there are age-related decrements of respiratory muscle strength and endurance of approximately 20% by the age of 70 years.¹⁴ Beginning in early adulthood, there is a progressive enlargement of the alveolar ducts and respiratory bronchioles. The effect of the enlargement of the terminal respiratory units is a decrease of functional alveolar surface area by 15% by the age of 70 years.⁷ The decrease in alveolar surface area reduces alveolar surface tension with consequential negative effect on alveolar gas exchange and forced expiratory flow.

The mechanical disadvantages are modest compared with the striking effect of age on the control of breathing. Elderly individuals have a significantly diminished response to hypoxia and hypercapnia,¹⁵ attributed to decreased tidal volume since respiratory rates are unchanged. While the cause of the decrement of tidal volume is multifactorial, altered receptor function probably plays the major role.¹⁶ Moreover, it has been demonstrated in the elderly that the perception of dyspnea is intact or even enhanced, but the compensatory response is reduced.¹⁷ Both slow and forced vital capacity decline with age.¹⁸ Cross-sectional studies estimate the decline in vital capacity from 21 to 34 mL/yr in men and 19 to 29 mL/yr in women; one longitudinal study estimates the rates to be a loss of 40 mL and 31.3 mL/yr, respectively, and that the rate accelerates with age. Also, the residual volume consistently increases with age, but the chest mechanics previously mentioned account for most of the longer expiration time. Closing volume increases linearly with age, from 10% of total lung capacity at age 20 years to 30% at age 70 years.⁷ The impact of the change is that by the mid-40s, closing volume approaches tidal volume in the supine position, and by 65 years they are equal in the sitting position. Essentially all expiratory flow rates decrease with age and tend to fall faster in men, taller individuals, and those with airway reactivity.

Changes in pulmonary circulation from age are difficult or impossible to separate from those circulatory changes attributable to the heart and circulatory system. In contrast to comparatively similar resting values with the young, the older person’s increased pulmonary artery and pulmonary capillary wedge pressures with exercise are significant, and increases of pulmonary artery resistance are highly significant with age.¹¹ Gas exchange declines at 0.5%/yr, a rate that correlates with the decrease in internal surface area of lung with age. The decline in PaO₂ with aging is notable and responds less to supplemental oxygen. Current thought is that increased closing volumes, dead space, and ventilation-perfusion mismatch are responsible, not hypoventilation.

The operative implications of the aging lung are several. Baseline arterial oxygenation is lower with age, and there is less response to supplemental inspired oxygen from disrupted ventilation and perfusion matching, increasing shunting and physiologic dead space. The risk of hypoxemia in patients > 70 years following sedation warrants supplemental oxygen for any procedure no matter what the baseline saturation. The older the individual, the smaller and the more delayed will be his/her response to hypoxemia and hypercarbia. The increased work of breathing with age compromises the capacity to meet additional workloads from surgery and contributes to acute postoperative ventilatory failure. In addition, opioid-induced chest wall rigidity is more frequent in the elderly.¹⁹ Medications can further compromise barely adequate respiratory muscle strength and endurance. Elderly subjects have a much higher incidence of apnea and periodic breathing with narcotics and respiratory depression from benzodiazepines. The markedly diminished response for vocal cord closure markedly increases the risk of aspiration and corresponding airway reaction and pulmonary injury.²⁰

	The Aging Heart and Blood Vessels

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
Concepts of the effect of aging on the cardiovascular system have become better understood but in some respects have not changed much since the turn of the century when Bramwell and Hill²¹ described the effect on cardiac metabolism and function of age-related progressive stiffening of the arteries. Studies of BP have revealed that systolic pressure rises approximately 6.0 to 7.0 mm Hg per decade,²² but diastolic pressure changes little with age²³ and may fall even as the systolic pressure rises.^{24 25} Multiple studies have stressed the impact of systolic pressure on cardiovascular events and the lack of cardiovascular events from elevations of diastolic BP in older adults.^{26 27} In addition, the systolic pressure is increasingly underestimated by the cuff sphygmomanometer with increasing age.

The intrinsic aging change on the arterial wall is predominantly in the media.²⁸ Atherosclerosis, in contrast, is an intimal disease. Throughout life, elastin fibers undergo progressive disorientation, fragmentation, and degeneration, with subsequent collagen deposition, calcification, and/or cystic degeneration. As a result, the central elastic arteries dilate and become tortuous. Age-related increase in arterial stiffness, which is limited to the aorta and central elastic arteries, is not found in the peripheral arteries.²⁹ This stiffness over time results in a doubling of pulse wave velocity in the aorta, a quadrupling of ascending aorta impedance, and a progressive rise in systolic pressure.

Most of the direct effects of aging on the heart are functionally minor. There is a linear loss of myocardial cells from infancy, estimated at 38 million per year, about the same proportion as is lost by the brain, liver, and kidney.³⁰ The remaining myocardial cells hypertrophy, the effect of which is ventricular wall thickness is well preserved over time. Although there is also an increase in fibrous connective tissue matrix, there is no corresponding neovascularity.³¹ Systolic function is relatively preserved. The velocity of myocardial shortening decreases, but the duration of contraction is prolonged.³² Diastolic changes are more noticeable. Delayed diastolic relaxation affects ventricular filling throughout diastole. Myocardial stiffness from muscle cell hypertrophy and fibrosis coupled with delayed ventricular relaxation lead to increased venous filling pressures. Like the respiratory system, with age the heart decreases its inotropic, chronotropic, and vascular responsiveness to catecholamines and sympathetic nervous system stimulation, apparently due to receptor factors.

In contrast to the direct effect, the impact of peripheral vascular changes on the aging heart is significant. Resting cardiac output, stroke volume, and peak aortic flow may change little with age, but the cardiovascular response to exercise declines progressively.³³ Maximal heart rate, stroke volume, cardiac output, ejection fraction, and oxygen uptake all decrease, whereas both end-systolic and end-diastolic volumes increase. It appears that increased impedance of the central elastic vessels with aging impairs ventricular performance, reduces ventricular ejection fraction, and decelerates aortic flow even in the absence of heart failure in the elderly.³⁴

The perioperative implications of aging itself logically follow. (The only age-related cardiac risk factor among Goldman’s factors is age!) Age-related diastolic dysfunction makes the elderly much more dependent on atrioventricular synchrony and much more affected by tachycardia.³⁵ Small decreases of venous filling from narcotics, diuretics, volume loss, or positive pressure ventilation can have profoundly negative effects on stroke volume and cardiac output. Inhalation anesthetics exaggerate the negative inotropic and chronotropic effects of calcium channel and ß-adrenergic blockers. Fluid volumes easily handled by young individuals may precipitate congestive heart failure and pulmonary edema in the elderly due to marginal resting reserve capacity. Perioperative hypotension is more frequent and more severe in the elderly than in the young.

The role of Swan-Ganz catheters to monitor filling pressures and volume status has become standard. For operations in the elderly, intraoperative transesophageal echocardiographic monitoring can be helpful, providing continuous estimates of left ventricular end-diastolic volumes and ejection fraction, and regional wall motion monitoring in compromised hearts. But age-related changes in vessels limit the usefulness of measurements of systemic vascular resistance in assessing cardiovascular function such as stroke volume, and the large discrepancies between cuff and invasive BP measurements in the elderly are well known.

	The Aging Kidney and Liver

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
The critical role of the kidney in fluid and electrolyte management, and both the liver and kidney in drug metabolism, mean that age-related changes in function are highly relevant to perioperative care. With aging, there is a loss of nephrons at a rate of 0.5 to 1% a year, mostly from the cortex. By the seventh decade of life, there is a 30 to 50% loss of functioning glomeruli due to age alone.³⁶ The loss of skeletal muscle mass with aging is proportionate to the loss in glomerular filtration so that the serum creatinine concentration generally changes little. Glomerular filtration rate is now commonly calculated using the Cockroft-Gault³⁷ equation: CCr(mL/min) = (140 - age[yr] x weight[kg])/(72 x serum Cr[mg/dL])

This formula is multiplied by 0.85 for women. The formula has been shown to correlate well with measured creatinine clearance in elderly patients and be a reliable guide for dosing drugs that are primarily renally eliminated. Actual body weight is used in the equation, but for obese individuals, ideal body weight should be used.

Medullary nephrons are relatively spared compared with cortical nephrons. Medullary nephrons have reduced concentrating ability and tend to excrete more free water. Elderly patients release more antidiuretic hormone in response to hypertonicity, but water retention is still less than in younger individuals because of reduced end-organ response in older persons. Older individuals tend to have diminished thirst perception and diminished awareness of volume contraction.³⁸ The response to aldosterone is impaired and the ability to conserve sodium limited. However, the excretion of a free water load, the mobilization of third space fluid, and elimination of excess salt are markedly delayed in elderly patients.³⁹

The calculated daily need for fluid also changes with declining total body water with increasing age. By the age of 80 years, the shift in body composition results in a 10 to 15% loss of total body water, mostly limited to the intracellular compartment; plasma volume and extracellular fluid volumes are well maintained in active elderly.

Hepatic mass also declines approximately 40% by age 80 years, with a proportionate decline in hepatic and splanchnic blood flow.⁴⁰ The quantitative loss of hepatic mass and blood flow accounts for most of the inadequate functional reserve of the liver because qualitatively, microsomal and nonmicrosomal hepatic enzyme activities per gram of liver tissue are virtually the same in young and old.⁴¹ The capacity for metabolism, biotransformation, and protein synthesis is more easily overwhelmed by the stresses of surgery and its complications. Elderly men metabolize benzodiazepines at rates slower than their younger counterparts, have reduced activity of hepatic cholinesterase, clear narcotics slower, and have depressed rates of induction of hepatic microsomal activity.

	Metabolism

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
In contrast to young adults, there is no consensus on the method of assessing nutritional status in the very old. Moreover, it has not been established in the very old that improvement in the nutritional indexes changes perioperative morbidity. Increased mortality occurs in underweight people, but mortality is not associated so clearly with elderly overweight. Progressive loss of skeletal mass, renal mass, and liver mass and the reciprocal increase in the lipid component of body composition results in a 10 to 15% reduction in metabolic requirements compared with young adults. There is a corresponding decrement in body heat production coupled with impairment of thermoregulatory vasoconstriction. The rate of intraoperative core body temperature fall, 1° per hour in geriatric patients, is twice the rate of younger adults under comparable conditions.⁴² The rate of postoperative warming decreases in direct proportion to increasing age.

As liver, kidney, and skeletal muscle mass decline and the lipid portion of the body increases, the distribution volume of lipid-soluble drugs increases, functioning as a reservoir for some drugs like anesthetic agents and benzodiazepines. Accordingly, delay in clearing drugs effects is often greater than expected due to the age-related reduction from hepatic and renal elimination.

	The Aging Nervous System

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
More than any other system, the changes in the nervous system define aging for a person and his/her family. Threshold stimuli for vision, hearing, touch, position, smell, taste, pain, and temperature all exponentially increase with age. The causes are multifactorial, including decline in receptors, fewer afferent conduction pathways, slower conduction, and fewer brain cells and connections. Efferent motor pathway conduction velocity declines by 0.15 m/s/yr. Coupled with slower corticospinal transmission, the overall impact is slower initiation of voluntary motor activity.⁴³

Like the rest of the peripheral nervous system, the neuronal loss in the autonomic nervous system progresses relentlessly with aging, resulting in 15% loss of neurons, adrenal mass, and cortisol secretion by age 80 years. Although levels vary greatly, catecholamine levels in the elderly are typically two to four times those of their younger counterparts at rest and with exercise.⁴⁴ It is not clinically evident because of a marked depression of end-organ responsiveness, apparently due more to qualitative changes in receptors rather than loss of adrenoreceptors.⁴⁵ Baroreceptor responsiveness, postural response, and vasoconstrictor response are all impaired in rate and magnitude. If the "hyperadrenergic" state is interrupted by medications, myocardial depression, or volume loss, arterial hypotension can be abrupt, severe, and difficult and slow to remediate.

The aging brain also loses mass, about 20% by the age of 80 years. The volume of the cranial vault occupied by the brain drops from 92% to 82% with a compensatory increase in cerebrospinal fluid. Cerebral blood flow declines proportionate to the age-related decline in neuronal mass, and autoregulation of cerebrovascular resistance is well maintained. Most of the neuronal loss is gray matter; current evidence is that there is little loss of nonneuronal glial cells. In general, the more metabolically active and highly specialized the neurons, the more susceptible the neurons are to loss. In the elderly, 50% of the neurons of the cerebral and cerebellar cortices, locus ceruleus, thalamus, and basal ganglia have undergone apoptosis, and the remaining synaptic interconnections are markedly simplified.⁴⁶ Neurotransmitters are proportionately diminished. Neither quantity nor sensitivity of receptors are increased in response. The impact on intellect is that crystallized intelligence such as language, personality, comprehension, general knowledge base, and long-term memory are preserved, while fluid intelligence declines as measured by visual and auditory reaction times, short-term memory, new learning, and visual-spacial coordination.

The anesthetic impact of changes in the nervous system is not as predictable as the anatomic and physiologic changes. Some generalizations can be made despite wide interindividual variation. Less anesthetic is needed for sensory blockade in spinal anesthesia. Similar findings have been demonstrated for local anesthesia and epidural anesthesia.⁴⁷ Elderly patients have increased pain threshold and increased sensitivity to narcotic analgesia.⁴⁸ The dose of neuromuscular-blocking drug needed to produce clinical effect does not change significantly with age, consistent with the observation of increased cholinergic receptors at motor end plates with aging, but the rates of clearance of essentially all the neuromuscular-blocking agents decline markedly with increasing age.

The dose requirements for benzodiazepines, barbiturates, and opioids vary among patients, but EEG has confirmed the general clinical experience of increasing sensitivity of the brain to narcotics. The exception to geriatric heterogeneity in anesthetic responsiveness is general anesthesia. Age-related increased sensitivity to inhaled and injected anesthetics is consistent, predictable, and progressive.⁴⁹ The dosing requirement drops nearly 30% by age 80 years. Studies have shown a direct relationship between brain neurotransmitter levels and anesthetic requirement.

Numerous clinical studies have shown no major surgical morbidity or mortality associated with the choice of anesthestic technique or agent. Therefore, no particular decision should be made on the form of anesthesia based on age alone. However, the recovery from inhaled anesthetic agents may require as long as 10 days. Hypothermia could prolong clearance and enhance anesthetic effect. Nitrous oxide, for reasons not understood, can have a prolonged effect on memory and mentation.⁵⁰

	Aging and Intellectual Impairment

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
Delirium is a vexing problem in perioperative care. The incidence of delirium may exceed 50% in the very old, is more frequent with increasing age, and is the most prevalent mental syndrome in hospitalized older persons.^{51 52} Delirium is marked by disturbances in consciousness (reduced clarity of awareness of surroundings), reduced ability to focus, and changes in cognition (development of perceptual disturbances). In contrast to dementia and depression, its onset is acute, and there is hour-to-hour fluctuation in severity. Age itself, dementia from any cause, undernutrition, acute situational stress, family history of mental illness, personal history of substance abuse, and nonambulatory status are risk factors.⁵³ Delirium is especially common after noncardiac thoracic and aortic aneurysm surgery. The underlying causes span a wide differential, some of which are life threatening. Delirium is associated with increased perioperative mortality—15 to 26% of elderly patients with delirium die—but the diagnosis is not recognized up to two-thirds of the time. Potentially fatal causes, such as infection, electrolyte disturbance, hypoglycemia, hypoxia, and hypotension, must be searched for and treated. Frequently pharmacologic toxicity is responsible. The list of drugs associated with delirium is long. It is especially common with anticholinergic agents, antipsychotic drugs, antidepressants, narcotic and nonnarcotic analgesics, digoxin, H₂-blockers, and antihypertensives. Environmental interventions such as controlling lighting, facilitating uninterrupted sleep, removing disembodied voices (such as radio or voices from the nurses’ station), and removing restraints may relieve delirium, but after addressing underlying causes and meticulous attention to drug intoxication, it may be necessary to treat agitated behavior with medication. Haloperidol, at doses 0.5 to 2.0 mg parenterally, can be given hourly until a sufficient response is achieved, but doses > 20 mg in 24 h are seldom indicated, and close monitoring for response and adverse effect is necessary.

	Functional Impairment

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
There is a growing appreciation of the functional impact of hospitalization on the elderly. In populations, functional status declines with age, but curiously, self-rated health does not.⁵⁴ Compared with individual baseline, most studies document a 30 to 50% rate of functional impairment from hospitalization, measurable as early as the second day of admission and lasting up to 3 months after discharge. Two factors that have major impacts on hospital discharge decisions are decline in mobility and loss of urinary continence. Preventive and restorative interventions are increasingly understood, but more often than not, the treatments for functional preservation are lost in the frantic pace of disease management in our hospitals. Adverse effects of treatment can mimic disease. Sedative-hypnotic use is associated with longer hospital stays.⁵⁵ A panel of nationally recognized experts in geriatrics and pharmacology has established a list of medications prone to contribute to functional impairment in the elderly and that therefore are best to avoid.⁵⁶

	Advance Directives

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
Much has been written about the benefit of advance directives, and great efforts have been expended to increase their prevalence without remarkable success. The average rate of advance directives at the time of discharge from hospitals is 10 to 15% despite interest and laws. Knowledge of desire regarding resuscitation is important, but in the perioperative period, the designation of an alternate decision-maker is especially important. As discussed above, up to half of elderly individuals may develop delirium in the critical postoperative period, a time when a health-care decision may impact the whole course of hospitalization. Experience has shown that when the designation of an alternate decision-maker is included on the surgical consent forms, > 90% of individuals will readily name a proxy, and up to a third of the time, the designee is not the next-of-kin whose opinion might ordinarily be sought.

	Conclusion

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 
As the population ages, increasing numbers of individuals will present for surgery, burdened by preexisting disease and its attendant comorbidities and complications. The effect of age has its own implications in perioperative care. With knowledge of age-related changes of anatomy and physiology, medications and interventions may be chosen with an understanding of the likely responses they will induce. Especially in the older person, therapeutic regimens should be simplified both pharmacologically and physically and reviewed regularly for efficacy and opportunity to eliminate unnecessary components and for particular sensitivity to functional impact.

	References

TOP Abstract Introduction The Aging Respiratory System The Aging Heart and... The Aging Kidney and... Metabolism The Aging Nervous System Aging and Intellectual... Functional Impairment Advance Directives Conclusion References

 

1. Hall, WJ (1997) Update in geriatrics. Ann Intern Med 127,557-564[Free Full Text]
2. US Bureau of Census. US population estimates by age, sex, race and Hispanic origin, 1989. Current Population Reports, series P-25, No. 1057; 1990
3. Shipton, EA (1983) The peri-operative care of the geriatric patient. S Afr Med J 63,855-860[ISI][Medline]
4. Santos, AL, Gelperin, A (1975) Surgical mortality in the elderly. J Am Geriatr Soc 23,42-46[ISI][Medline]
5. Wilcox, SM, Himmelstein, DU, Woolhandler, S (1994) Inappropriate drug prescribing for the community-dwelling elderly. JAMA 272,292-296[Abstract]
6. Classen, DC, Pestotnik, SL, Evans, RS, et al (1997) Adverse drug events in hospitalized patients: excess length of stay, extra costs, and attributable mortality. JAMA 277,301-306[Abstract]
7. Carpo, RO, Campbell, EJ (1998) Aging of the respiratory system. Fishamn, AP eds. Pulmonary diseases and disorders ,251-264 McGraw-Hill New York, NY.
8. Gibellino, F, Osmanliev, DP, Watson, A, et al (1985) Increase in tracheal size with age: implications for maximal expiratory flow. Am Rev Respir Dis 132,784-787[ISI][Medline]
9. Knudson, RJ, Clark, DF, Kennedy, TC, et al (1977) Effect of aging alone on mechanical properties of the normal adult human lung. J Appl Physiol 43,1054-1062[Abstract/Free Full Text]
10. Shapiro, SD, Endicott, SK, Province, MA, et al (1990) Marked longevity of human lung parenchymal elastic fibers deduced from prevalence of D-aspartate and nuclear weapons-related radiocarbon. J Clin Invest 87,1828-1834
11. Ehrsam, RE, Perruchaud, A, Oberholzer, M, et al (1983) Influence of age on pulmonary hemodynamics at rest and during supine exercise. Clin Sci 65,653-660[Medline]
12. Mittman, C, Edelman, NH, Norris, AH, et al (1965) Relationship between chest wall and pulmonary compliance and age. J Appl Physiol 20,1211-1216[Abstract/Free Full Text]
13. Mahler, DA, Rosiella, RA, Loke, J (1986) The aging lung. Geriatr Clin North Am 2,215-225
14. Chen, HS, Kuo, CS (1989) Relationship between respiratory muscle function and age, sex, and other factors. J Appl Physiol 66,943-948[Abstract/Free Full Text]
15. Kronenberg, RS, Drage, CW (1973) Attenuation of the ventilatory and heart rate responses to hypoxia and hypercapnia with aging in normal men. J Clin Invest 53,1812-1819
16. Peterson, DD, Fishman, AP (1992) Aging of the respiratory system. Fishman, AP eds. Update: pulmonary diseases and disorders ,1-17 McGraw-Hill New York, NY.
17. Akiyama, Y, Nishimure, M, Kobayaski, S, et al (1993) Effects of aging on respiratory load compensation and dyspnea sensation. Am Rev Respir Dis 148,1586-1591[ISI][Medline]
18. Ware, JH, Dockery, DW, Louis, TA, et al (1990) Longitudinal and cross-sectional estimates of pulmonary function decline in never-smoking adults. Am J Epidemiol 132,685-700[Abstract/Free Full Text]
19. Bailey, PL, Wilbrink, J, Zwanikken, P, et al (1985) Anesthetic induction with fentanyl. Anesth Analg 64,48-53[Abstract/Free Full Text]
20. Pontoppidan, H, Beecher, HK (1960) Progressive loss of protective reflexes in the airway with advanced age. JAMA 174,2209-2213[ISI][Medline]
21. Bramwell, JC, Hill, AV (1922) Velocity of transmission of the pulse wave and elasticity of arteries. Lancet 1,891-892
22. Rodriquez, BL, Larbarthe, DR, Huang, B, et al (1994) Rise of blood pressure with age: new evidence of population differences. Hypertension 24,779-785[Abstract/Free Full Text]
23. Nichols, WW, Pepine, CJ (1992) Ventricular/vascular interaction in health and heart failure. Compr Ther 18,12-19[Medline]
24. Kannel, WB (1985) Hypertension and aging. Finch, CE Schneider, EL eds. The biology of aging ,859-877 Van Nostrand Reinold New York, NY.
25. Franklin, SS, Gustin, W, IV, Wong, ND, et al (1997) Hemodynamic patterns of age-related changes in blood pressure. Circulation 96,308-315[Abstract/Free Full Text]
26. Franklin, SS, Weber, MA (1994) Measuring hypertensive cardiovascular risk: the vascular concept. Am Heart J 128,793-803[CrossRef][ISI][Medline]
27. Avanzini, F, Bettelli, G, Alli, C, et al (1995) The prognostic significance of systolic and diastolic blood pressure in the elderly: suggestions of a 10 year follow-up study. J Am Coll Cardiol 25,178A
28. Nichols, WW, O’Rourke, MF (1998) Aging. Nichols, WW O’Rourke, MF eds. McDonald’s blood flow in arteries: theoretical, experimental, and clinical principles ,355-358 Oxford University Press New York, NY.
29. Benetos, A, Laurent, S, Hoeks, AP, et al (1993) Arterial alterations with aging and high blood pressure: a non-invasive study of carotid and femoral arteries. Atherosclerosis Thromb 13,90-97
30. Olivetti, G, Melissari, M, Capasso, JM, et al (1991) Cardiomyopathy of the aging heart: myocyte loss and reactive cell hypertrophy. Circ Res 68,1560-1568[Abstract/Free Full Text]
31. Morley, JE, Reece, SS (1989) Clinical implications of the aging heart. Am J Med 86,77-86[ISI][Medline]
32. Lakatta, EG (1993) Cardiovascular regulatory mechanisms in advanced age. Physiol Rev 73,413[Free Full Text]
33. Stratton, JR, Levy, WC, Cerqueira, MD, et al (1994) Cardiovascular responses to exercise; effects of aging and exercise training in healthy men. Circulation 89,1648-1655[Abstract/Free Full Text]
34. Westerhof, N, O’Rourke, MF (1995) Haemodynamic basis for development of left ventricular failure in systolic hypertension and for its logical therapy. J Hyperten 13,943-952[ISI][Medline]
35. Geokas, MC, Lakatta, EG, Makinodan, T, et al (1990) The aging process. Ann Intern Med 113,455-466[ISI][Medline]
36. Lindeman, RD (1993) Renal physiology and pathophysiology of aging. Contrib Nephrol 105,1-12[Medline]
37. Cockroft, DW, Gault, MH (1976) Prediction of creatinine clearance for serum creatinine. Nephron 16,31-41[ISI][Medline]
38. Phillips, PA, Rolls, BJ, Ledingham, JGC, et al (1984) Reduced thirst after water deprivation in health elderly men. N Engl J Med 311,753-759[Abstract]
39. Epstein, M, Hollenberg, NK (1976) Age as a determinant of renal sodium conservation in normal man. J Lab Clin Med 87,411-417[ISI][Medline]
40. Kampmann, JP, Sinding, J, Moller-Jorgensen, I (1975) Effect of age on liver function. Geriatrics 30,91-95[ISI][Medline]
41. Woodhouse, KW, Mutch, E, Williams, FM, et al (1984) The effect of age on pathways of drug metabolism in human liver. Age Ageing 13,328-344[Abstract/Free Full Text]
42. Kurz, A, Plattner, O, Sessler, DI, et al (1993) The threshhold for thermoregulatory vasoconstriction during nitrous oxide/isoflurane anesthesia is lower in elderly than in young patients. Anesthesiology 79,465-469[CrossRef][ISI][Medline]
43. Dorfman, LJ, Bosley, TM (1979) Age-related changes in peripheral and central nerve conduction in man. Neurology 29,38-44[Abstract/Free Full Text]
44. Ziegler, MG, Lake, CR, Kopin, IJ (1976) Plasma noradrenaline increases with age. Nature 261,333-335[CrossRef][Medline]
45. Docherty, JR (1993) Effect of age on the response of target organs to autonomic neurotransmitters. Amenta, F eds. Aging of the autonomic nervous system ,109 CRC Press Boca Raton, FL.
46. Feldman, ML (1976) Aging changes in the morphology of cortical denddrites. Terry, RD Gershon, S eds. Neurobiology of aging ,11 Raven Press New York, NY.
47. Sharrock, NE (1978) Epidural responses in patients 20 to 80 years old. Anesthesiology 49,425-428[CrossRef][ISI][Medline]
48. Bellville, JW, Forrest, WH, Jr, Miller, E, et al (1971) Influence of age on pain relief from analgesics: a study of postoperative patients. JAMA 217,1835-1841[CrossRef][Medline]
49. Muravchick, S (1996) Anesthesia for the geriatric patient. Barash, PG eds. Clinical anesthesia ,1131-1133 Lippincott-Raven Philadelphia, PA.
50. O’Keeffe, ST, Ni Chonchubhair, A (1994) Postoperative delirium in the elderly. Br J Anaesth 73,673-687[Free Full Text]
51. Berggren, D, Gustafson, Y, Eriksson, B, et al (1987) Postoperative confusion after anesthesia in elderly patients with femoral neck fractures. Anesth Analg 66,497-504[Abstract/Free Full Text]
52. Pompei, P, Foreman, M, Rudberg, MA, et al (1994) Delirium in hospitalized older persons: outcomes and predictors. J Am Geriatr Soc 42,809-815[ISI][Medline]
53. Marcantonio, ER, Goldman, L, Mangione, CM, et al (1994) A clinical prediction rule for delirium after elective noncardiac surgery. JAMA 271,134-139[Abstract]
54. Hoeymans, N, Feskens, EJ, van de Bos, GAM, et al (1997) Age, time, and cohort effects on functional status and self-rated health in elderly men. Am J Public Health 87,1620-1625[Abstract/Free Full Text]
55. Zisselman, MH, Rovner, BW, Yeun, EJ, et al (1996) Sedative-hypnotic use and increased hospital stay and costs in older people. J Am Geriatr Soc 44,1371-1374[ISI][Medline]
56. Owens, NJ (1989) The relationship between comprehensive functional assessment and optimal pharmacology in the older patient. DICP 23,847-854[Abstract]

This article has been cited by other articles:

				F. Hamard, M. Ferrandiere, X. Sauvagnac, J. C. Mangin, J. Fusciardi, C. Mercier, and M. Laffon La sedation au propofol permet l'intubation difficile vigile avec le masque larynge FastrachTM: [Propofol sedation allows awake intubation of the difficult airway with the FastrachTM LMA] Can J Anesth, April 1, 2005; 52(4): 421 - 427. [Abstract] [Full Text] [PDF]

				Y. Fukukawa, C. Nakashima, S. Tsuboi, N. Niino, F. Ando, S. Kosugi, and H. Shimokata The Impact of Health Problems on Depression and Activities in Middle-Aged and Older Adults: Age and Social Interactions as Moderators J. Gerontol. B. Psychol. Sci. Soc. Sci., January 1, 2004; 59(1): P19 - 26. [Abstract] [Full Text] [PDF]

				S. J. Hoff, S. K. Ball, W. H. Coltharp, D. M. Glassford Jr, J. W. Lea IV, and M. R. Petracek Coronary artery bypass in patients 80 years and over: is off-pump the operation of choice? Ann. Thorac. Surg., October 1, 2002; 74(4): S1340 - 1343. [Abstract] [Full Text] [PDF]

				H.-J. Priebe The aged cardiovascular risk patient Br. J. Anaesth., November 1, 2000; 85(5): 763 - 778. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Free Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Oskvig, R. M. Search for Related Content PubMed PubMed Citation Articles by Oskvig, R. M.