Critical care for the elderly patient

Critical Illness in the Elderly: Review of Pathophysiology of Aging and Outcome of Intensive Care

The goal of this article is to review the literature on age and its influence on the pathophysiology of critical illness, outcome after critical illness, and end of life decision making in critically ill elderly patients. Sources for this review included the MEDLINE database and bibliographies of original articles, reviews, and book chapters. The population is aging and the need for medical care and its costs increase with increasing age. A majority of the elderly lead independent lives, although some need help with various functional activities related to daily living. It is difficult to separate the effects of aging from the effects of the comorbidities that develop with increasing age. The physiologic reserve decreases in the elderly and they may not be able to tolerate a critical injury or illness as well as a younger individual. As the elderlyare usually on multiple medications, they are prone to have more drug interactions and side effects, and need close monitoring of the drugs and adjustment of the dosage. Mortality after a critical illness in the elderly is higher compared to younger patients, and it is more related to the acuity of physiologic disturbance than age alone. The effect of age alone on long-term outcome is not well studied, but individuals with poor functional status and/or increased comorbidities have a poor short-term outcome. Functional status usually deteriorates after critical illness, but the long-term survivors usually recover functional abilities, and they are satisfied with their quality of life. Decision making at the end of life is difficult because of the paucity of data on long-term mortality and quality of life, lack of information about patient wishes, and the uncertainty of the prognosis. Because many elderly patients survive critical illness and may return to their previous lifestyle, age alone should not weigh heavily in end of life decisions. As with other age groups, end of life decisions in the elderly should be made after considering long-term outcomes, patient goals, and the benefits and burdens of life-sustaining technology.

Adipogenic signaling in rat white adipose tissue: modulation by aging and calorie restriction

Alterations in adipogenesis could have significant impact on several aging processes. We previously reported that calorie restriction (CR) in rats significantly increases the level of circulating adiponectin, a distinctive marker of differentiated adipocytes, leading to a concerted modulation in the expression of key transcription target genes and, as a result, to increased fatty acid oxidation and reduced deleterious lipid accumulation in other tissues. These findings led us to investigate further the effects of aging on adipocytes and to determine how CR modulates adipogenic signaling in vivo. CR for 2 and 25 months, significantly increased the expression of PPARgamma, C/EBPbeta and Cdk-4, and partially attenuated age-related decline in C/EBPalpha expression relative to rats fed ad libitum (AL). As a result, adiponectin was upregulated at both mRNA and protein levels, resulting in activation of target genes involved in fatty acid oxidation and fatty acid synthesis, and greater responsiveness of adipose tissue to insulin. Moreover, CR significantly decreased the ratio of C/EBPbeta isoforms LAP/LIP, suggesting the suppression of gene transcription associated with terminal differentiation while facilitating preadipocytes proliferation. Morphometric analysis revealed a greater number of small adipocytes in CR relative to AL feeding. Immunostaining confirmed that small adipocytes were more strongly positive for adiponectin than the large ones. Overall these results suggest that CR increased the expression of adipogenic factors, and maintained the differentiated state of adipocytes, which is critically important for adiponectin biosynthesis and insulin sensitivity.

Geriatric critical care

Demographic compulsions are inescapable. There has been a 50% increase in life expectancy at birth for persons born in 1980 compared to those born in 1900. Not only do critical care units utilize up to a third of hospital expenditures and about 1% of GNP, the critically ill elderly consume a disproportionate amount of ICU resources. Outcome prediction models for very elderly critically ill patients have been proposed with age as one of numerous model variables; but such models have not been widely validated. Despite the burgeoning emphasis on evidence-based population approach to health care, there is insufficient research to guide the critical care clinician. There remains a modicum of subjectivity in crucial decisions that affect the elderly patient receiving intensive care. Older age is also one of the factors that lead to a physician bias in refusing ICU admission; this has recently been borne out in a multivariate analysis. Physicians generally consider their older patients' quality of life to be worse than do the patients, although other studies that have assessed the quality of live show no age-related differences among ICU survivors. Furthermore, physicians' estimations of patient quality of life significantly influence physicians' attitudes to futility of care issues, in contrast to patients' perceptions. Threshold for life-sustaining treatment in the elderly will continue to be different among the ICUs. In critical care of the elderly, geography may well be destiny. Clinical decisions will be subjected to many ethical, legal, and socioeconomic pressures. Personal and religious beliefs will inevitably influence societal expectations and clinician practices. Severity of illness has the biggest influence on outcome in a critical illness. Age alone is not a predictor of short-term or long-term outcome in the older patient who is critically ill. Critical illness in the elderly remains a fertile area for future research.

Weaning Older Patients From Long-term Mechanical Ventilation: A Pilot Study

• Background As older persons in the intensive care unit increasingly require long-term mechanical ventilation, accurate indications of readiness for weaning from ventilatory support are needed to avoid premature extubation.

• Objective To describe temporal changes in pulmonary and systemic variables in older adults receiving long-term mechanical ventilation.

• Methods After 3 days of unsuccessful attempts at weaning from ventilatory support, 10 trauma and surgical patients more than 60 years old were monitored daily. Previously reported predictors of the duration of mechanical ventilation and weaning outcome were measured, including hemodynamic and gas exchange variables, oxygen cost of breathing, and the score on the Burns Weaning Assessment Program.

• Results The 6 patients who could be weaned from ventilatory support were younger (median age, 71.5 years) than the 4 patients who could not be weaned (median age, 80 years). Patients who could be weaned were ready for weaning by day 11 of their stay in the intensive care unit and required an additional 5.5 days of mechanical ventilation; those who could not be weaned were not ready for weaning until day 17. All patients initially had increases in oxygen consumption during weaning; those who were successfully weaned had decreases before extubation. Respiratory rate, maximal inspiratory pressure, the ratio of Pao2 to fraction of inspired oxygen, and mean arterial pressure were higher in patients who could be weaned, and oxygen cost of breathing and central venous pressure were lower.

• Conclusion Further study of weaning in older adults is warranted.

Altered expression of C/EBP family members results in decreased adipogenesis with aging

Fat mass, adipocyte size and metabolic responsiveness, and preadipocyte differentiation decrease between middle and old age. We show that expression of CCAAT/enhancer binding protein (C/EBP)-α, a key regulator of adipogenesis and fat cell function, declined substantially with aging in differentiating preadipocytes cultured under identical conditions from rats of various ages. Overexpression of C/EBPα in preadipocytes cultured from old rats restored capacity to differentiate into fat cells, indicating that downstream differentiation-dependent genes maintain responsiveness to regulators of adipogenesis. C/EBPα-expression also decreased with age in fat tissue from three different depots and in isolated fat cells. The overall level of C/EBPβ, which modulates C/EBPα-expression, did not change with age, but the truncated, dominant-negative C/EBPβ-liver inhibitory protein (LIP) isoform increased in cultured preadipocytes and isolated fat cells. Overexpression of C/EBPβ-LIP in preadipocytes from young rats impaired adipogenesis. C/EBPδ, which acts with full-length C/EBPβ to enhance adipogenesis, decreased with age. Thus processes intrinsic to adipose cells involving changes in C/EBP family members contribute to impaired adipogenesis and altered fat tissue function with aging. These effects are potentially reversible.

Elderly trauma: they are different

The elderly currently represent 11 per cent of the Australian population. By the year 2051 it has been estimated that 24 per cent of the population will be older than 65 years. One of the hazards facing the elderly is the risk of trauma. With this in mind, this paper has two major aims: one is to review the incidence and outcome of elderly trauma and the other is to identify pertinent points when assessing and managing the elderly trauma patient. Background information for this paper was obtained from the Australia Bureau of Statistics, Roads and Traffic Authority and Injury Surveillance Unit. A comprehensive literature review was then undertaken using the Medline and CINAHL databases.

Comorbid conditions in old patients with femur fractures

BACKGROUND AND METHODS

The incidence of preexisting medical diseases (comorbid conditions) and their influence on the high rate of falls, associated severe injuries, operative treatment, and outcome including mortality rate, duration of hospitalization, and rehabilitation success was retrospectively evaluated in a group of 102 patients (mean age, 81 years; 81% women) with femoral fractures. A comparison of polymorbidity rates in a control group of 102 patients (mean age, 79 years; 86% women) with proximal humeral fractures was added.

RESULTS

The associated polymorbidity rate among patients with femoral fractures (FF) usually was statistically significantly higher than among patients with proximal humeral fractures (PHF) despite a comparable age and sex distribution: 80% of the patients with FF presented with cardiovascular (p < or = 0.001), 41% with pulmonary (p < 0.001), 67% with gastrointestinal (p < or = 0.001), 71% with neurologic (p < or = 0.001), 55% with urologic (p < or = 0.001), 75% with musculoskeletal (p < or = 0.1), and 61% with psychiatric (p < or = 0.001) disorders and complaints. Ninety percent of the patients used different medications (diuretics, cardiac agents, anticoagulants, antidiabetic agents, steroids, hypnotics, analgesics, psychotropic agents). The postoperative mortality rate was 11%, and the mean hospitalization period was 30 days. Forty-nine percent of the patients were discharged to their homes. Only 56% of the patients with PHF, however, presented with cardiovascular, 8% with pulmonary, 11% with gastrointestinal, 8% with neurologic, 9% with urologic, 64% with musculoskeletal, and 10% with psychiatric disorders.

CONCLUSION

The polymorbidity in the old patient probably is a major intrinsic cause of the high incidence of falls and associated severe femoral fractures. It influences the perioperative and postoperative medical and anesthesiologic treatment, the postoperative mortality rate, and the duration and success of the postoperative rehabilitation phase.

Preadipocyte function and aging: links between age-related changes in cell dynamics and altered fat tissue function

OBJECTIVE

To review recent findings about changes with age in the replication and differentiation of preadipocytes, the progenitor cells in fat tissue that are capable of differentiating into fat cells, and to examine possible links between these alterations and age-related changes in fat tissue function.

DESIGN

A survey and analysis of recent literature concerning changes in preadipocyte and fat cell function with age.

CONCLUSIONS

Intrinsic aging changes in fat cells and preadipocytes as well as in factors extrinsic to fat tissue (such as food intake and absorption and hormonal status) contribute to age-related alterations in fat tissue function and cellularity. Changes with age in preadipocyte number, replicative potential, and capacity for differentiation, which may be linked to aging changes in fat cell size, number, and function, have been identified. The decline in preadipocyte capacity for differentiation and the associated decline in fat cell lipogenic capacity may be particularly important in contributing to the decrease in fat mass and alterations in fat tissue function that occur between middle- and old age. These declines result from blunting of the changes in gene expression that occur during preadipocyte differentiation and may, in turn, be related to altered regulation of particular transcription factors that control the preadipocyte differentiation program and maintenance of fat cell function.

Energy Needs Are Poorly Predicted in Critically Ill Elderly

Changes in energy expenditure with age have been described, but this physiology is not routinely considered when managing critically ill elderly patients. To allow us to avoid the potential problems associated with underfeeding or overfeeding the critically ill elderly population, with approval of the human studies committee and appropriate consent from legal guardians, 25 critically ill patients over 65 years of age requiring mechanical ventilation underwent expired gas indirect calorimetry. If they had a pulmonary artery catheter in place for clinical reasons, reverse-Fick indirect calorimetry was also performed. Data obtained by indirect calorimetry was compared with commonly applied equations for predicting energy expenditure by statistical methods of correlation and limits of agreement. These 25 patients had an average age of 74 ± 1.23 (standard error of the mean) and an average APACHE II score of 15. Predictive equations correlated poorly with measured resting energy expenditure, and although they showed reasonable bias, they were imprecise in their estimation of resting energy expenditure. These data suggest that energy expenditure in critically ill, mechanically ventilated elderly patients is highly variable. Although generally overestimating energy needs, currently available equations for predicting energy expenditure in this population are associated with significant bias and imprecision, which may lead to both overfeeding and underfeeding. Although these equations may be suitable as a basis of initiating nutritional support, energy provisions should ideally be guided by indirect calorimetry.