Allowing a patient's nutritional state to deteriorate through the perioperative period adversely affects measureable outcome related to nosocomial infection, multiple organ dysfunction, wound healing, and functional recovery. Careful preoperative nutritional assessment should include a determination of the level of stress, an evaluation of the status of the GI tract, and the development of specific plans for securing enteral access. Patients already demonstrating compromise of nutritional status (defined by > 10% weight loss and serum albumin level < 2.5 g/dL) should be considered for a minimum of 7 to 10 days of nutritional repletion prior to surgery. Widespread use of total parenteral nutrition in unselected patients is unwarranted, may actually worsen outcome, and should be reserved for preoperative nutritional support only in severely malnourished patients in whom the GI tract is unavailable. Compared with the parenteral route, use of perioperative enteral feeding has been shown to provide more consistent and beneficial results, and can be expected to promote specific advantages in long-term morbidity and mortality.

A summary of current modalities for and the utility of preoperative assessment of pulmonary risk.

Preoperative cardiac evaluation is aimed at evaluating the patient's current medical status, making recommendations concerning the risk of cardiac problems in the perioperative period, and providing a clinical risk profile that the patient, primary physician, consultants, anesthesiologist, and surgeon can use in making treatment decisions. Patients can be stratified on clinical grounds into low-, medium-, and high-risk categories. Use of these categories, along with consideration of the type and urgency of noncardiac surgery, allows for a reasonable approach to preoperative testing. In general, indications for cardiac testing and treatment are similar to the nonoperative setting, but their choice and timing is dependent on factors specific to the patient, the type of surgery, and the clinical situation. Use of invasive and noninvasive testing should be limited to situations in which the results of the tests will clearly affect patient management. Further research is necessary to define the most appropriate role of such testing, both in terms of efficacy and of cost-effectiveness. Cardiac intervention is rarely necessary to lower the risk of surgery, but noncardiac surgery often represents the first opportunity for a patient to receive an appropriate assessment of short- and long-term cardiac risk, and this should be taken into consideration in planning perioperative evaluation.

To characterize adult Mycoplasma pneumoniae-induced bronchiolitis requiring hospitalization.

The upper airway resistance syndrome (UARS) is a recently described form of sleep-disordered breathing in which repetitive increases in resistance to airflow within the upper airway lead to brief arousals and daytime somnolence. This review will first describe the chronological progression of our understanding of UARS within the broader context of sleep-disordered breathing. The primary symptom, daytime somnolence, appears to result directly from repetitive EEG arousals. The level of negative intrathoracic pressure is the most likely stimulus for arousal, possibly mediated by mechanoreceptors in the upper airway. A general consensus regarding the exact clinical definitions and the physiologic measurement techniques leading to a diagnosis does not exist, although esophageal manometry and pneumotachographic airflow measurements taken during polysomnography are the "gold standard." Less invasive diagnostic modalities have been proposed, but none of them have been well-validated. Aside from daytime somnolence, hypertension is an important sequela of this disorder, likely resulting from autonomic and cardiovascular changes induced by increased negative intrathoracic pressure. Nasal continuous positive airway pressure is the most efficacious form of therapy, although low patient compliance may limit its practical application. The safety and efficacy of surgical treatments are poorly documented in the literature. Palatal tissue reduction by radiofrequency ablation and the use of oral appliances hold promise as safe and effective modalities, but these treatments require further study.

To identify and critically review the published peer-reviewed, English-language studies of the effects of both spontaneous and simulated gastroesophageal reflux (GER) on pulmonary function in asthmatic adults.

Chronic heart failure (CHF) is a complex syndrome affecting many body systems. Body wasting (ie, cardiac cachexia) is a serious complication of CHF long known but little investigated. Although no specific diagnostic criteria have been established, we have suggested that cardiac cachexia be defined on the basis of the presence of documented nonintentional and nonedematous weight loss > 7.5% of the premorbid normal weight, occurring over a time period of > 6 months. Using this definition, 16% of an unselected CHF outpatient population was found to be cachectic. The cachectic state is predictive of impaired prognosis independently of age, functional disease classification, left ventricular ejection fraction, and peak oxygen consumption. The mortality in the cachectic cohort is 50% at 18 months. Analyzing body composition in detail, it has been found that patients with cardiac cachexia suffer from a general loss of fat tissue (ie, energy reserves), lean tissue (ie, skeletal muscle), and bone tissue (ie, osteoporosis). Cachectic CHF patients are weaker and fatigue earlier, which is due to both reduced skeletal muscle mass and impaired muscle quality. The pathophysiologic alterations leading to cardiac cachexia remain unclear, but initial cross-sectional studies have suggested that humoral neuroendocrine and immunologic abnormalities are linked, independently of established heart failure severity markers, to the presence of body wasting. Comparing the features of cachectic and noncachectic CHF patients with those of healthy control subjects, it is mainly the cachectic CHF patients who show raised plasma levels of epinephrine, norepinephrine, and cortisol; the highest plasma renin activity and aldosterone plasma concentrations; and the lowest plasma sodium level. Several studies have shown that cardiac cachexia is linked to raised plasma levels of tumor necrosis factor-ac. The degree of body wasting is strongly correlated with neurohormonal and immune abnormalities. The available evidence suggests that cardiac cachexia is a multifactorial neuroendocrine and metabolic disorder with a poor prognosis. A complex imbalance of different body systems may cause the development of body wasting.

Patients hospitalized in ICUs are 5 to 10 times more likely to acquire nosocomial infections than other hospital patients. The frequency of infections at different anatomic sites and the risk of infection vary by the type of ICU, and the frequency of specific pathogens varies by infection site. Contributing to the seriousness of nosocomial infections, especially in ICUs, is the increasing incidence of infections caused by antibiotic-resistant pathogens. Prevention and control strategies have focused on methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and extended-spectrum beta-lactamase-producing Gram-negative bacilli, among others. An effective infection control program includes a surveillance system, proper handwashing, appropriate patient isolation, prompt evaluation and intervention when an outbreak occurs, adherence to standard guidelines on disinfection and sterilization, and an occupational health program for health-care providers. Studies have shown that patients infected with resistant strains of bacteria are more likely than control patients to have received prior antimicrobials, and hospital areas that have the highest prevalence of resistance also have the highest rates of antibiotic use. For these reasons, programs to prevent or control the development of resistant organisms often focus on the overuse or inappropriate use of antibiotics, for example, by restriction of widely used broad-spectrum antibiotics (e.g., third-generation cephalosporins) and vancomycin. Other approaches are to rotate antibiotics used for empiric therapy and use combinations of drugs from different classes.

Diagnostic and treatment strategies in ICU patients with ventilator-associated pneumonia (VAP) remain controversial, largely because of the paucity of well-controlled comparison trials using clinically important end points. Recent studies indicating that early appropriate antibiotic therapy significantly lowers mortality underscore the urgent need for well-designed comparative trials. When quantitatively cultured, bronchial specimens obtained by noninvasive techniques may provide clinically useful information and avoid the higher costs and risks of invasive bronchoscopic diagnostic techniques. Previous antibiotic use before onset of nosocomial pneumonia raises the likelihood of infection with highly virulent organisms, such as Pseudomonas aeruginosa and Acinetobacter sp. Thus, the empiric antibiotic regimen should be active against these Gram-negative pathogens as well as other common Gram-negative and Gram-positive causative organisms. Promising preventive modalities for nosocomial VAP include use of a semirecumbent position, endotracheal tubes that allow continuous aspiration of secretions, and heat and moisture exchangers. Rotating their standard empiric antibiotic regimens and restricting the use of third-generation cephalosporins as empiric therapy may help hospitals reduce the incidence of nosocomial pneumonia caused by resistant Gram-negative pathogens.

Rising antibiotic resistance rates among bacterial pathogens have resulted in increased morbidity and mortality from nosocomial infections. Widespread use of certain antibiotics, particularly third-generation cephalosporins, has been shown to foster development of generalized beta-lactam resistance in previously susceptible bacterial populations. Reduction in the use of these agents (as well as imipenem and vancomycin) and concomitant increases in the use of extended-spectrum penicillins and combination therapy with aminoglycosides have been shown to restore bacterial susceptibility. Studies have shown that education-based methods, as opposed to coercive measures, are effective in changing the prescribing habits of physicians. Cooperative interaction among infectious-disease physicians, clinical pharmacists, microbiology-laboratory personnel, and infection-control specialists is essential to provide useful suggestions regarding antibiotic choice and dosing to the prescribing physician in real time. Several hospitals have implemented antimicrobial resistance management programs based on these findings. The results of these programs validate the use of a multidisciplinary, education-based, antibiotic-resistance management approach.

Pharmacodynamic properties can be used to divide antibiotics into two major classes based on their mechanism of bactericidal action: (1) concentration-dependent drugs, such as aminoglycosides and fluoroquinolones, and (2) concentration-independent drugs, including the beta-lactams. Antibiotics also differ in the postantibiotic effect (PAE) that they exert. In general, concentration-dependent drugs have a more prolonged PAE than concentration-independent drugs, particularly against Gram-negative pathogens. Pharmacodynamic classifications have important implications for the planning of drug regimens. For concentration-dependent drugs, peak concentration to minimal inhibitory concentration (MIC) ratios of approximately 10 are associated with clinical success. Therefore, high drug levels should be the goal of therapy. This is best achieved by high doses taken once daily. This approach, however, is not feasible for the fluoroquinolones owing to dose-limiting CNS toxicity. Concentration-independent agents are most effective when the duration of serum concentrations is higher than the pathogen's MIC (time >MIC) for a significant proportion of the dosing interval. Frequent dosing or continuous infusions can increase the time >MIC. Concentrations of antibiotics that are sublethal can permit the emergence of resistant pathogens. Optimization of antibiotic regimens on the basis of pharmacodynamic principles could thus significantly diminish the emergence of antibiotic resistance.

The Infectious Diseases Society of America (IDSA) has published guidelines for the treatment of community-acquired pneumonia (CAP). Although Streptococcus pneumoniae remains the most common etiologic agent, Chlamydia pneumoniae and Legionella pneumophila are also important causes. For all suspected CAP patients, particularly those requiring hospitalization, chest radiographs are strongly recommended to confirm the diagnosis. The IDSA guidelines, in contrast to those published by the American Thoracic Society, emphasize the use of sputum Gram's stain and culture in all patients, whenever possible, to establish etiology. This information can be used not only to guide therapy but also to track trends in the etiologic pathogens for CAP and their antibiotic susceptibility. In light of the better outcomes with the earliest possible interventions, the IDSA recommends initial empiric antimicrobial therapy until laboratory results can be obtained to guide more specific therapy. Macrolides, doxycycline, and fluoroquinolones are suggested for primary empiric therapy, since each has activity against common bacterial pathogens and atypical agents. Detailed antibiotic recommendations are made for various pathogens. For inpatients, attempts should be made to cover Legionella and other common pathogenic bacteria. Alternative antibiotics are recommended for patients with structural diseases of the lung, penicillin allergy, or suspected aspiration pneumonia. Switch to an appropriate oral antibiotic is recommended as soon as the patient's condition is stable and he or she can tolerate oral therapy, often within 72 h.

The tremendous therapeutic advantage afforded by antibiotics is being threatened by the emergence of increasingly resistant strains of microbes. Selective pressure favoring resistant strains arises from misuse and overuse of antimicrobials (notably extended-spectrum cephalosporins), increased numbers of immunocompromised hosts, lapses in infection control, increased use of invasive procedures and devices, and the widespread use of antibiotics in agriculture and animal husbandry. Outside the hospital, penicillin-resistant Streptococcus pneumoniae is of greatest concern; recent reports also indicate the appearance of outpatient methicillin-resistant Staphylococcus aureus (MRSA) infections. MRSA is a significant problem in the hospital, as are vancomycin-resistant Enterococcus, oxacillin-resistant S aureus, and multidrug-resistant Gram-negative bacilli. Owing to the high rate of antibiotic use and other risk factors, a person is more likely to acquire an antibiotic-resistant infection in the ICU than anywhere else, either inside or outside the hospital. Responsible antibiotic use and stringent infection-control policies are needed to discourage the development of resistant strains.

A 64-year-old man presented with an asymptomatic left lower lobe mass. At bronchoscopy there was a tumor in the superior segment. Biopsy revealed an acinic cell carcinoma. There was no evidence of salivary gland or other site of origin. Lobectomy and lymph node staging showed involvement of interlobar (N1) nodes, while higher stations were benign. The patient remains well 20 months postoperatively. This is the only instance of primary pulmonary acinic cell carcinoma with lymph node metastasis among 15 cases in the literature. We review the clinical features, histology, and treatment of the reported cases.

A healthy 34-year-old man had a mediastinal cyst on the imaging study. Surgical treatment was performed. The cyst was diagnosed as a thoracic duct cyst from its anatomic location and contents. Pathologic examination found it to be consistent with thoracic duct cyst. Endothelial cells on its luminal surface were identified by an immunohistologic stain with the factor VIII-related antigen. Twenty-six cases of thoracic duct cysts have been reported. We report an additional case and review the previously reported cases. We found that the ligation of the inferior pedicle of the cyst is essential to prevent postoperative chylothorax.

This review examines the hypothesis that excess lung cancer risk in worker cohorts exposed to asbestos occurs only among those with asbestosis. The adequately designed studies in the literature support this hypothesis. The summary relative risk for lung cancer was 1.00 in seven cohorts with no deaths from asbestosis. In addition, there is a high correlation between asbestosis rates and lung cancer rates in 38 cohorts in contrast to a poor correlation between cumulative exposure data and lung cancer relative risks in eight cohorts with adequate data. The evidence indicates that asbestosis is a much better predictor of excess lung cancer risk than measures of exposure and serves as a marker for attributable cases.

To define the epidemiology, pathogenesis, pathology, presentation, and management of tuberculous mycotic aneurysm of the aorta (TBAA) in the therapeutic era, we reviewed all of the cases reported in the English language literature from 1945 to the present. To the 39 cases in the published literature, we add two cases of our own. Although it is exceedingly rare, the prevalence of this lesion has remained relatively constant. In 75% of the cases, TBAA appeared to result from erosion of the aortic wall by a contiguous focus; 25% from direct seeding of the aortic intima or of the adventitia or media (via the vasa vasorum). Most of the aneurysms were saccular (90%) and false (88%). The thoracic and abdominal aortas were affected with equal frequency. The mean (+/- SD) age of the patients was 50+/-16 years. Twenty-two were men, and 19 were women. In 63% of the cases, tuberculosis (TB) was diagnosed at presentation. Disseminated TB was present in 46% of the cases. One or more of three clinical scenarios suggested TBAA: persistent pain, major bleeding, and a palpable or radiographically visible para-aortic mass, especially if it is expanding or pulsatile. In turn, each of these findings suggested a complication of TBAA that may be an indication for surgical intervention. Among the patients who were offered both medical and surgical treatment, 20 of 23 (87%) survived. Among those who were offered only one form of treatment or were offered no treatment at all there were no survivors. Both in situ reconstruction with a prosthetic graft, and extra-anatomic bypass appeared to offer excellent results, provided that an effective regimen of antituberculous drugs was delivered postoperatively. We offer our conclusions: (1) symptomatic TBAA is a rare but uniformly fatal lesion if not diagnosed promptly, (2) in the context of active TB, and especially miliary TB, TBAA should be suspected whenever one or more of the three clinical scenarios are present, and (3) combined medical and surgical therapy appears to offer the best chance of a cure.