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Background: The reported accuracy of transbronchial needle aspiration (TBNA) for mediastinal staging in non-small cell lung cancer (NSCLC) varies widely. We performed a meta-analysis to estimate the accuracy of TBNA for mediastinal staging in NSCLC. Methods: Medline, Embase, and the bibliographies of retrieved articles were searched for studies evaluating TBNA accuracy with no language restriction. Meta-analytical methods were used to construct summary receiver-operating characteristic curves and to pool sensitivity and specificity. Results: Thirteen studies met inclusion criteria, including six studies that surgically confirmed all TBNA results and enrolled at least 10 patients with and without mediastinal metastasis (tier 1). Methodological quality varied but did not affect diagnostic accuracy. In tier 1 studies the median prevalence of mediastinal metastasis was 34%. Using a random effects model, the pooled sensitivity and specificity were 39% (95% Cl 17 to 61) and 99% (95% Cl 96 to 100), respectively. Compared with tier 1 studies, the median prevalence of mediastinal metastasis (81 %; p = 0.002) and pooled sensitivity (78%; 95% Cl 71 to 84; p = 0.009) were higher in non-tier 1 studies. Sensitivity analysis confirmed that the sensitivity of TBNA depends critically on the prevalence of mediastinal metastasis. The pooled major complication rate was 0.3% (95%Cl 0.01 to 4). Conclusions: When properly performed, TBNA is highly specific for identifying mediastinal metastasis in patients with NSCLC, but sensitivity depends critically on the study methods and patient population. In populations with a lower prevalence of mediastinal metastasis, the sensitivity of TBNA is much lower than reported in recent lung cancer guidelines. [ABSTRACT FROM AUTHOR]

Context: Focal pulmonary lesions are commonly encountered in clinical practice, and positron emission tomography (PET) with the glucose analog 18-fluorodeoxyglucose (FDG) may be an accurate test for identifying malignant lesions.Objective: To estimate the diagnostic accuracy of FDG-PET for malignant focal pulmonary lesions.Data Sources: Studies published between January 1966 and September 2000 in the MEDLINE and CANCERLIT databases; reference lists of identified studies; abstracts from recent conference proceedings; and direct contact with investigators.Study Selection: Studies that examined FDG-PET or FDG with a modified gamma camera in coincidence mode for diagnosis of focal pulmonary lesions; enrolled at least 10 participants with pulmonary nodules or masses, including at least 5 participants with malignant lesions; and presented sufficient data to permit calculation of sensitivity and specificity were included in the analysis.Data Extraction: Two reviewers independently assessed study quality and abstracted data regarding prevalence of malignancy and sensitivity and specificity of the imaging test. Disagreements were resolved by discussion.Data Synthesis: We used a meta-analytic method to construct summary receiver operating characteristic curves. Forty studies met inclusion criteria. Study methodological quality was fair. Sample sizes were small and blinding was often incomplete. For 1474 focal pulmonary lesions of any size, the maximum joint sensitivity and specificity (the upper left point on the receiver operating characteristic curve at which sensitivity and specificity are equal) of FDG-PET was 91.2% (95% confidence interval, 89.1%-92.9%). In current practice, FDG-PET operates at a point on the summary receiver operating characteristic curve that corresponds approximately to a sensitivity and specificity of 96.8% and 77.8%, respectively. There was no difference in diagnostic accuracy for pulmonary nodules compared with lesions of any size (P =.43), for semiquantitative methods of image interpretation compared with qualitative methods (P =.52), or for FDG-PET compared with FDG imaging with a modified gamma camera in coincidence mode (P =.19).Conclusions: Positron emission tomography with 18-fluorodeoxyglucose is an accurate noninvasive imaging test for diagnosis of pulmonary nodules and larger mass lesions, although few data exist for nodules smaller than 1 cm in diameter. In current practice, FDG-PET has high sensitivity and intermediate specificity for malignancy. [ABSTRACT FROM AUTHOR]

Background: Patients in the intensive care unit (ICU) often experience poor sleep quality. Pharmacologic sleep aids are frequently used as primary or adjunctive therapy to improve sleep, although their benefits in the ICU remain uncertain. This review aims to provide a comprehensive assessment of the objective and subjective effects of medications used for sleep in the ICU, as well as their adverse effects. Methods: PubMed, Web of Science, Scopus, Embase, and Cochrane Central Register of Controlled Trials were systematically searched from their inception until June 2023 for comparative studies assessing the effects of pharmacologic sleep aids on objective and subjective metrics of sleep. Results: Thirty-four studies with 3498 participants were included. Medications evaluated were melatonin, ramelteon, suvorexant, propofol, and dexmedetomidine. The majority of studies were randomized controlled trials. Melatonin and dexmedetomidine were the best studied agents. Objective sleep metrics included polysomnography (PSG), electroencephalography (EEG), bispectral index, and actigraphy. Subjective outcome measures included patient questionnaires and nursing observations. Evidence for melatonin as a sleep aid in the ICU was mixed but largely not supportive for improving sleep. Evidence for ramelteon, suvorexant, and propofol was too limited to offer definitive recommendations. Both objective and subjective data supported dexmedetomidine as an effective sleep aid in the ICU, with PSG/EEG in 303 ICU patients demonstrating increased sleep duration and efficiency, decreased arousal index, decreased percentage of stage N1 sleep, and increased absolute and percentage of stage N2 sleep. Mild bradycardia and hypotension were reported as side effects of dexmedetomidine, whereas the other medications were reported to be safe. Several ongoing studies have not yet been published, mostly on melatonin and dexmedetomidine. Conclusions: While definitive conclusions cannot be made for most medications, dexmedetomidine improved sleep quantity and quality in the ICU. These benefits need to be balanced with possible hemodynamic side effects., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Malnutrition in adult intensive care unit patients is associated with poor clinical outcomes. Providing adequate nutritional support to the critically ill adult should be an important goal for the intensivist. This narrative review aims to delineate the role of parenteral nutrition (PN) in meeting nutritional goals. We examined the data regarding the safety and efficacy of PN compared to enteral nutrition. In addition, we describe practical considerations for the use of PN in the ICU including patient nutritional risk stratification, nutrient composition selection for PN, route of PN administration, and biochemical monitoring., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objectives: Characterise inhalational exposures during deployment to Afghanistan and Southwest Asia and associations with postdeployment respiratory symptoms., Methods: Participants (n=1960) in this cross-sectional study of US Veterans (Veterans Affairs Cooperative Study 'Service and Health Among Deployed Veterans') completed an interviewer-administered questionnaire regarding 32 deployment exposures, grouped a priori into six categories: burn pit smoke; other combustion sources; engine exhaust; mechanical and desert dusts; toxicants; and military job-related vapours gas, dusts or fumes (VGDF). Responses were scored ordinally (0, 1, 2) according to exposure frequency. Factor analysis supported item reduction and category consolidation yielding 28 exposure items in 5 categories. Generalised linear models with a logit link tested associations with symptoms (by respiratory health questionnaire) adjusting for other covariates. OR were scaled per 20-point score increment (normalised maximum=100)., Results: The cohort mean age was 40.7 years with a median deployment duration of 11.7 months. Heavy exposures to multiple inhalational exposures were commonly reported, including burn pit smoke (72.7%) and VGDF (72.0%). The prevalence of dyspnoea, chronic bronchitis and wheeze in the past 12 months was 7.3%, 8.2% and 15.6%, respectively. Burn pit smoke exposure was associated with dyspnoea (OR 1.22; 95% CI 1.06 to 1.47) and chronic bronchitis (OR 1.22; 95% CI 1.13 to 1.44). Exposure to VGDF was associated with dyspnoea (OR 1.29; 95% CI 1.14 to 1.58) and wheeze (OR 1.18; 95% CI 1.02 to 1.35)., Conclusion: Exposures to burn pit smoke and military occupational VGDF during deployment were associated with an increased odds of chronic respiratory symptoms among US Veterans., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Since 2001, more than 2.7 million U.S. military personnel have been deployed in support of operations in Southwest Asia and Afghanistan. Land-based personnel experienced elevated exposures to particulate matter and other inhalational exposures from multiple sources, including desert dust, burn pit combustion, and other industrial, mobile, or military sources. A workshop conducted at the 2018 American Thoracic Society International Conference had the goals of: 1 ) identifying key studies assessing postdeployment respiratory health, 2 ) describing emerging research, and 3 ) highlighting knowledge gaps. The workshop reviewed epidemiologic studies that demonstrated more frequent encounters for respiratory symptoms postdeployment compared with nondeployers and for airway disease, predominantly asthma, as well as case series describing postdeployment dyspnea, asthma, and a range of other respiratory tract findings. On the basis of particulate matter effects in other populations, it also is possible that deployers experienced reductions in pulmonary function as a result of such exposure. The workshop also gave particular attention to constrictive bronchiolitis, which has been reported in lung biopsies of selected deployers. Workshop participants had heterogeneous views regarding the definition and frequency of constrictive bronchiolitis and other small airway pathologic findings in deployed populations. The workshop concluded that the relationship of airway disease, including constrictive bronchiolitis, to exposures experienced during deployment remains to be better defined. Future clinical and epidemiologic research efforts should address better characterization of deployment exposures; carry out longitudinal assessment of potentially related adverse health conditions, including lung function and other physiologic changes; and use rigorous histologic, exposure, and clinical characterization of patients with respiratory tract abnormalities.

Objectives: We conducted two parallel studies evaluating the effectiveness of proactive and reactive engagement approaches to telephone treatment for smoking cessation., Methods: Patients who smoked and were interested in quitting were referred to this study and were eligible if they were current smokers and had an address and a telephone number. The data were collected at 35 Department of Veterans Affairs (VA) sites, part of four VA medical centres in both California and Nevada. In study 1, participants received multisession counselling from the California Smokers' Helpline (quitline). In study 2, they received self-help materials only. Patients were randomly assigned by week to either proactive or reactive engagement, and primary care staff were blind to this assignment. Providers gave brief advice and referred them via the electronic health record to a tobacco co-ordinator. All patients were offered cessation medications., Outcome: Using complete case analysis, in study 1 (quitline), patients in the proactive condition were more likely than those in the reactive condition to report abstinence at 6 months (21.0% vs 16.4%, p=0.03). No difference was found between conditions in study 2 (self-help) (16.9% vs 16.5%, p=0.88). Proactive outreach resulted in increased use of cessation medications in both the quitline (70.1% vs 57.6%, p<0.0001) and the self-help studies (74.5% vs 48.2%, p<0.0001)., Conclusion: Proactive outreach with quitline intervention was associated with greater long-term abstinence. Both studies resulted in high rates of medication use. Sites should use a proactive outreach approach and provide counselling whenever possible., Trial Registration Number: NCT00123682., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Introduction: Circulating tumor microemboli (CTM) are potentially important cancer biomarkers, but using them for cancer detection in early-stage disease has been assay limited. We examined CTM test performance using a sensitive detection platform to identify stage I non-small-cell lung cancer (NSCLC) patients undergoing imaging evaluation., Methods: First, we prospectively enrolled patients during 18F-FDG PET-CT imaging evaluation for lung cancer that underwent routine phlebotomy where CTM and circulating tumor cells (CTCs) were identified in blood using nuclear (DAPI), cytokeratin (CK), and CD45 immune-fluorescent antibodies followed by morphologic identification. Second, CTM and CTC data were integrated with patient (age, gender, smoking, and cancer history) and imaging (tumor diameter, location in lung, and maximum standard uptake value [SUVmax]) data to develop and test multiple logistic regression models using a case-control design in a training and test cohort followed by cross-validation in the entire group., Results: We examined 104 patients with NSCLC, and the subgroup of 80 with stage I disease, and compared them to 25 patients with benign disease. Clinical and imaging data alone were moderately discriminating for all comers (Area under the Curve [AUC] = 0.77) and by stage I disease only (AUC = 0.77). However, the presence of CTM combined with clinical and imaging data was significantly discriminating for diagnostic accuracy in all NSCLC patients (AUC = 0.88, p value = 0.001) and for stage I patients alone (AUC = 0.87, p value = 0.002)., Conclusion: CTM may add utility for lung cancer diagnosis during imaging evaluation using a sensitive detection platform.

Introduction: We investigated the relationship of circulating tumor cells (CTCs) in non-small cell lung cancer (NSCLC) with tumor glucose metabolism as defined by (18)F-fluorodeoxyglucose (FDG) uptake since both have been associated with patient prognosis., Materials & Methods: We performed a retrospective screen of patients at four medical centers who underwent FDG PET-CT imaging and phlebotomy prior to a therapeutic intervention for NSCLC. We used an Epithelial Cell Adhesion Molecule (EpCAM) independent fluid biopsy based on cell morphology for CTC detection and enumeration (defined here as High Definition CTCs or "HD-CTCs"). We then correlated HD-CTCs with quantitative FDG uptake image data calibrated across centers in a cross-sectional analysis., Results: We assessed seventy-one NSCLC patients whose median tumor size was 2.8 cm (interquartile range, IQR, 2.0-3.6) and median maximum standardized uptake value (SUVmax) was 7.2 (IQR 3.7-15.5). More than 2 HD-CTCs were detected in 63% of patients, whether across all stages (45 of 71) or in stage I disease (27 of 43). HD-CTCs were weakly correlated with partial volume corrected tumor SUVmax (r = 0.27, p-value = 0.03) and not correlated with tumor diameter (r = 0.07; p-value = 0.60). For a given partial volume corrected SUVmax or tumor diameter there was a wide range of detected HD-CTCs in circulation for both early and late stage disease., Conclusions: CTCs are detected frequently in early-stage NSCLC using a non-EpCAM mediated approach with a wide range noted for a given level of FDG uptake or tumor size. Integrating potentially complementary biomarkers like these with traditional patient data may eventually enhance our understanding of clinical, in vivo tumor biology in the early stages of this deadly disease.

Purpose: The present work aimed to extend models suggesting that obstructive sleep apnea (OSA) is associated with worse cognitive performance in community-dwelling older adults. We hypothesized that in addition to indices of OSA severity, hypertension is associated with worse cognitive performance in such adults., Methods: The PTSD Apnea Clinical Study recruited 120 community-dwelling, male veterans diagnosed with PTSD, ages 55 and older. The Rey Auditory Verbal Learning Test (RAVLT) and Color-Word Interference Test (CWIT) were measures of auditory verbal memory and executive function, respectively. Apnea-hypopnea index (AHI), minimum and mean pulse oximeter oxygen saturation (min SpO(2), mean SpO(2)) indicators were determined during standard overnight polysomnography. Multivariate linear regression and receiver operating characteristic (ROC) curve analyses were performed., Results: In regression models, AHI (β = -4.099; p < 0.01) and hypertension (β = -4.500; p < 0.05) predicted RAVLT; hypertension alone (β = 9.146; p < 0.01) predicted CWIT. ROC analyses selected min SpO(2) cut-points of 85% for RAVLT (κ = 0.27; χ² = 8.23, p < 0.01) and 80% for CWIT (κ = 0.25; χ² = 12.65, p < 0.01). Min SpO(2) cut-points and hypertension were significant when added simultaneously in a regression model for RAVLT (min SpO(2), β = 4.452; p < 0.05; hypertension, β = -4.332; p < 0.05), and in separate models for CWIT (min SpO(2), β = -8.286; p < 0.05; hypertension, β = -8.993; p < 0.01)., Conclusions: OSA severity and presence of self-reported hypertension are associated with poor auditory verbal memory and executive function in older adults.

Objective: To test the effectiveness of a care coordination program for telephone counseling in raising referral and treatment rates for smoking cessation., Study Design: A demonstration project implementing a smoking cessation care coordination program offering telephone counseling and medication management to patients referred from primary care., Methods: The study was performed at 18 Veterans Health Administration (VA) sites in California. Participants were VA patients receiving primary care. We randomly allocated 10 of 18 sites to receive the Telephone Care Coordination Program, which included simple 2-click referral, proactive care coordination, medication management, and 5 follow-up telephone calls. Each patient received a 30- to 45-minute counseling session from the California Smokers' Helpline. Patients at control sites received usual care., Results: During 10 months, we received 2965 referrals. We were unable to reach 1156 patients (39%), despite at least 3 attempts. We excluded 73 patients (3%), and 391 patients (13%) were not interested. We connected the remaining 1345 patients (45%) to the Helpline. At 6-month followup, 335 patients (11% of all referrals and 25% of participating patients) were abstinent. Providers at intervention sites reported referring many more patients to telephone counseling than providers at control sites (15.6 vs 0.7 in the prior month)., Conclusions: The program generated a large number of referrals; almost half of the patients referred were connected with the Helpline. Long-term abstinence was excellent. These results suggest that managed care organizations may be able to improve tobacco control by implementing a similar system of care coordination.

Background: Multiple reports have described associations between occupational inhalant exposure and lung disease. Previous occupational lung disease investigations have studied populations consisting of both smokers and nonsmokers. Smoking complicates interpretation of toxicant exposure-response relationships. The objective of this study was to determine whether, among never-smokers, occupational exposure to gases, dusts, or fumes is associated with a history of respiratory disorders and pulmonary function test defined obstructive lung disease., Methods: We performed a retrospective analysis of 517 never-smoker patients who underwent pulmonary function testing in our clinical laboratory between 1986 and 1999. We calculated the relative risks of developing adverse respiratory health outcomes given a history of exposure to occupational inhalants., Results: Compared with persons with a negative occupational exposure history, exposed persons had an increased risk of reporting a history of bronchitis [relative risk (RR), 1.59; 95% confidence interval (CI), 1.20-2.12], recurrent lung infections (RR, 2.09; 95% CI, 1.14-3.82), and bronchodilator use (RR, 1.61; 95% CI, 1.26-2.06). There was also a statistically significant association between a history of inhalant exposure and the finding of an obstructive ventilatory defect on pulmonary function testing (RR, 1.79; 95% CI, 1.12-2.85). A history of inhalant exposure was not associated with self-reported asthma (RR, 1.08; 95% CI, 0.83-1.41). The population attributable risk estimates for respiratory disorders due to inhalant exposure were: bronchitis, 23.6%; recurrent lung infection, 36.3%; bronchodilator use, 24.3%; and obstructive lung disease, 29.6%., Conclusions: Occupational inhalant exposure is a strong risk factor for lung disease in this population of never smokers. A significant burden of respiratory disease in this population may be attributable to occupational inhalant exposure.

We report a rare case of foreign body aspiration diagnosed by microscopic analysis of a sample of the foreign body. A 50-year-old man presented with a 5-month history of 40 pound weight loss and a nonresolving right lower lobe pneumonia. Medical history, radiographic studies, direct visualization of the foreign body by flexible fiberoptic bronchoscopy, and gross examination of a sample of the foreign body retrieved by a forceps biopsy catheter failed to yield the diagnosis. Moderate bleeding associated with the bronchoscopic "biopsy" procedure contributed to a preliminary misdiagnosis of endobronchial tumor. Microscopic analysis of the "biopsy" specimen demonstrated vegetable matter. The patient underwent rigid bronchoscopy and a peanut was retrieved from the bronchus intermedius. He was maintained on antibiotics for an additional 8 weeks and had complete clinical and radiographic recovery. The epidemiology, presentation, and management strategies of foreign body aspiration in the adult are briefly reviewed.

Introduction: The conclusion of previous investigations that pulmonary rehabilitation (PR) is an effective intervention for the management of chronic lung disease may not be generalizable to PR programs with limited experience delivering this complex, interdisciplinary service., Objective: Determine whether PR is effective for the first group of patients treated in a newly formed interdisciplinary PR program., Methods: We conducted a longitudinal analysis of changes in health-related quality of life and 6-minute walk test for the first group of patients completing our newly formed 8-week outpatient PR program. We studied 6 men, age 65-77 years, with stable severe chronic obstructive pulmonary disease. Patients completed the Chronic Respiratory Disease Questionnaire immediately before and 1 year after participation in our PR program., Results: Four patients completed the PR 6-minute walk test both before and after the program. We found improvement in all Chronic Respiratory Disease Questionnaire domains at follow-up (mean +/- SD before and after): dyspnea 1.67 +/- 0.82 vs 4.92 +/- 0.49; emotional function 2.33 +/- 0.82 vs 5.50 +/- 0.55; fatigue 2.00 +/- 0.63 vs 5.00 +/- 0.63; feeling of mastery over disease 1.83 +/- 0.41 vs 5.83 +/- 1.17. The interval improvements in all health-related quality of life domains were statistically significant (p < 0.02 for all comparisons). There was a trend toward improvement in exercise tolerance: 231 +/- 213 ft before PR vs 353 +/- 66 ft at the 1-year follow-up (p = 0.2)., Conclusions: PR can result in sustained improvement in the quality of life of patients with severe chronic obstructive pulmonary disease, even when this complex, interdisciplinary service is delivered by a newly formed and inexperienced PR program.

Benzocaine (ethyl aminobenzoate) is a local anesthetic commonly used to achieve topical anesthesia of the skin and mucous membranes prior to endoscopic procedures. Methemoglobinemia, a condition in which hemoglobin cannot bind and deliver oxygen normally, has been associated with benzocaine use in various patient populations. This is the first report of benzocaine-associated methemoglobinemia occurring in a healthy research participant. The research participant developed a methemoglobin level of 27% and marked cyanosis. No adverse sequelae other than cyanosis were identified. This report extends the population in which benzocaine-associated methemoglobinemia has been described. Additionally, this report supports the observation that methemoglobin levels approaching 30% may be tolerated in otherwise healthy individuals, producing few clinically important effects. Finally, this case also indicates that, in obtaining informed consent for a procedure in which benzocaine will be administered, patients and research participants should be specifically informed of the risk of benzocaine-induced methemoglobinemia. This information is especially important in those settings in which the manufacturer-recommended dose of benzocaine may either intentionally or inadvertently be exceeded.

Esophageal variceal hemorrhage is frequently a catastrophic event. The specific events that trigger variceal rupture are not well understood. Acute elevations in systemic blood pressure and increased splanchnic blood flow, however, may lead to increased intravariceal pressure followed by variceal rupture and hemorrhage. This report describes a strong temporal association between complicated endotracheal intubation and abrupt onset of life-threatening variceal hemorrhage. A 52-year-old man with a history of portal hypertension was intubated emergently for airway protection because of respiratory insufficiency due to sepsis. Intubation was complicated by initial inadvertent esophageal intubation and by a peak mean arterial blood pressure of 155 mmHg. At the conclusion of the procedure, the patient sustained large volume hematemesis due to esophageal variceal rupture. This case suggests a risk of triggering variceal hemorrhage as a result of intubation-induced increase in blood pressure. A number of agents, including fentanyl, have been shown to be effective in attenuating the cardiovascular response to intubation. This case report provides strong evidence in support of administering fentanyl, or a suitable alternative adjunctive medication, before intubation of patients with documented portal hypertension and a history of esophageal variceal hemorrhage.

Study Objectives: To describe the clinical and radiographic findings associated with growth of Mycobacterium gordonae in cultured sputum and to determine the proportion of cases that fulfill criteria for nontuberculous mycobacterial pulmonary disease as established by the American Thoracic Society., Design: A retrospective review of charts and radiographs of all patients from whom M gordonae was isolated from sputum cultures between November 1996 and June 1998., Setting: University-affiliated Veterans Affairs hospital., Patients: Nineteen patients were identified with sputum culture positive for M gordonae. All patients had a chest radiograph within 1 month of sputum culture., Results: Sixteen patients (84%) had suppressed local and/or general immunity. Sixteen patients (84%) had respiratory symptoms, weight loss, fever, or night sweats as an indication for chest radiography. Seventeen patients (89%) had abnormal chest radiographs; however, no typical radiographic pattern was observed. No patient met diagnostic criteria for nontuberculous mycobacterial pulmonary disease as delineated by the American Thoracic Society. All patients with abnormal chest radiographs and/or respiratory symptoms ultimately had alternative explanations for their pulmonary disease., Conclusions: There is a broad spectrum of chest radiographic findings among persons with sputum culture positive for M gordonae, arguing against the presence of a characteristic chest radiograph in this patient population. M gordonae is usually a nonpathogenic colonizing organism, even among persons with local or general immune suppression and abnormal chest radiograph findings.

Asthma is often easily identified and effectively treated. However, presenting symptoms are variable, and many cases of asthma may not be obvious or typical. Since asthma affects about 5% of the US population, primary care physicians should be prepared to identify and manage both atypical and classic types. Atypical symptoms include disturbed sleep, chest tightness, and persistent cough without audible wheezing. Occupational factors should be suspected in all cases of adult-onset asthma. The patient's history and results of simple pulmonary function tests are useful in diagnosing, staging, and managing asthma. A beta 2 agonist delivered by metered-dose inhaler (e.g., albuterol) should provide prompt relief of most exacerbations. Inhaled corticosteroid therapy delivered via a spacer helps prevent exacerbations and has an important role in long-term control of moderate and severe asthma. If symptoms do not improve with the use of standard asthma medications, alternative diagnoses should be considered.

Asthma is a common chronic illness characterized by episodes of reversible airflow obstruction. A cornerstone of asthma management is identifying and avoiding agents that cause bronchospasm. The workplace is an important potential source of respirable exposures that can cause or trigger asthma. Identification of an occupational factor in asthma is important: early diagnosis and removal of the worker from the exposure is associated with improved prognosis; the diagnosis of occupational asthma may lead to compensation for work-related impairment and disability; and the diagnosis of occupational asthma is a Sentinel Health Event with implications for public health and prevention. In this article, we review specific causes of occupational asthma and general settings in which an occupational factor should be suspected and explored as part of the management of the worker with asthma. We also review specific and simple elements of history and pulmonary function testing that can be easily assessed by most health care practitioners and may be sufficient to establish a diagnosis of occupational asthma. Finally, we review the medical-legal implications of occupational asthma.

Respiratory exposure to zinc oxide results in metal fume fever, a flu-like illness characterized by dose-dependent increases in pulmonary tumor necrosis factor-alpha (TNF) and interleukin-8 (IL-8). To examine whether mononuclear cells are a source of these proinflammatory cytokines, we exposed U937 cells to zinc oxide in vitro. Cell culture supernatant TNF and IL-8 was measured after 3, 8, and 24 hours of exposure to zinc oxide in varying concentrations. Zinc oxide exposure in vitro led to TNF release in a dose-dependent manner at 3, 8, and 24 hours (analysis of variance [ANOVA] P = 0.0001). IL-8 demonstrated a statistically significant zinc exposure response at 8 hours (ANOVA P = 0.005) and 24 hours (ANOVA P = 0.02). IL-8 at 8 hours correlated with 3-hour TNF levels (r = 0.52, P = 0.04). These data demonstrate that in vitro zinc oxide exposure stimulates U937 mononuclear cells to release TNF and IL-8 consistent with in vivo observations in metal fume fever.