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ObjectivesTo evaluate measurement discrepancies by race between pulse oximetry and arterial oxygen saturation (as measured in arterial blood gas) among inpatients not in intensive care.DesignMulticenter, retrospective cohort study using electronic medical records from general care medical and surgical inpatients.SettingVeteran Health Administration, a national and racially diverse integrated health system in the United States, from 2013 to 2019.ParticipantsAdult inpatients in general care (medical and surgical), in Veteran Health Administration medical centers.Main outcomes measuresOccult hypoxemia (defined as arterial blood oxygen saturation (SaO2) of 2) reading of ≥92%), and whether rates of occult hypoxemia varied by race and ethnic origin.ResultsA total of 30 039 pairs of SpO2-SaO2readings made within 10 minutes of each other were identified during the study. These pairs were predominantly among non-Hispanic white (21 918 (73.0%)) patients; non-Hispanic black patients and Hispanic or Latino patients accounted for 6498 (21.6%) and 1623 (5.4%) pairs in the sample, respectively. Among SpO2values greater or equal to 92%, unadjusted probabilities of occult hypoxemia were 15.6% (95% confidence interval 15.0% to 16.1%) in white patients, 19.6% (18.6% to 20.6%) in black patients (Pvwhite patients, with similar P values in adjusted models), and 16.2% (14.4% to 18.1%) in Hispanic or Latino patients (P=0.53vwhite patients, P2-SaO2pairs restricted to occur within 5 minutes and 2 minutes. In white patients, an initial SpO2-SaO2pair with little difference in saturation was associated with a 2.7% (95% confidence interval −0.1% to 5.5%) probability of SaO22-SaO2reading showing an SpO2of 92%, but black patients had a higher probability (12.9% (−3.3% to 29.0%)).ConclusionsIn general care inpatient settings across the Veterans Health Administration where paired readings of arterial blood gas (SaO2) and pulse oximetry (SpO2) were obtained, black patients had higher odds than white patients of having occult hypoxemia noted on arterial blood gas but not detected by pulse oximetry. This difference could limit access to supplemental oxygen and other more intensive support and treatments for black patients.

Background Although inhaled therapy reduces exacerbations among patients with COPD, the effectiveness of providing inhaled treatment per risk stratification models remains unclear. Research Question Are inhaled regimens that align with the 2017 Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy associated with clinically important outcomes? Study Design and Methods We conducted secondary analyses of Long-term Oxygen Treatment Trial (LOTT) data. The trial enrolled patients with COPD with moderate resting or exertional hypoxemia between 2009 and 2015. Our exposure was the patient-reported inhaled regimen at enrollment, categorized as either aligning with, undertreating, or potentially overtreating per the 2017 GOLD strategy. Our primary composite outcome was time to death or first hospitalization for COPD. Additional outcomes included individual components of the composite outcome and time to first exacerbation. We generated multivariable Cox proportional hazard models across strata of GOLD-predicted exacerbation risk (high vs low) to estimate between-group hazard ratios for time to event outcomes. We adjusted models a priori for potential confounders, clustered by site. Results The trial enrolled 738 patients (73.4% men; mean age, 68.8 years). Of the patients, 571 (77.4%) were low risk for future exacerbations. Of the patients, 233 (31.6%) reported regimens aligning with GOLD recommendations; most regimens (54.1%) potentially overtreated. During a 2.3-year median follow-up, 332 patients (44.9%) experienced the composite outcome. We found no difference in time to composite outcome or death among patients reporting regimens aligning with recommendations compared with undertreated patients. Among patients at low risk, potential overtreatment was associated with higher exacerbation risk (hazard ratio, 1.42; 95% CI, 1.09-1.87), whereas inhaled corticosteroid treatment was associated with 64% higher risk of pneumonia (incidence rate ratio, 1.64; 95% CI, 1.01-2.66). Interpretation Among patients with COPD with moderate hypoxemia, we found no difference in clinical outcomes between inhaled regimens aligning with the 2017 GOLD strategy compared with those that were undertreated. These findings suggest the need to reevaluate the effectiveness of risk stratification model-based inhaled treatment strategies.

Background: Early experience during the coronavirus disease (COVID-19) pandemic and predictive modeling indicate that the need for respiratory therapists (RTs) will exceed the current supply. Objective: We present an implemented model to train and deploy medical students in the novel role of “respiratory therapist extender” (RTE) to address respiratory therapist shortage during the COVID-19 pandemic. Methods: The RTE role was formulated through discussions with respiratory therapists. A three-part training, with both online and in-person components, was developed and delivered to 25 University of Michigan Medical Students. RTEs were trained in basic respiratory care, documentation, equipment preparation, and equipment processing for clinically stable patients. They operate in a tiered staffing model in which RTEs report to a single RT, thereby extending his/her initial capacity. Results: The first cohort of safely trained RTEs was deployed to provide patient care within 1 week of volunteer recruitment. Conclusion: Our experience has demonstrated that healthcare professionals, including medical students, can be quickly trained and deployed in the novel RTE role as a surge strategy during the COVID-19 pandemic. Because we urgently developed and implemented the RTE role, we recognize the need for ongoing monitoring and adaptation to ensure patient and volunteer safety. We are sharing the RTE concept and training openly to help address RT shortages as the pandemic evolves.

Racial Bias in Pulse Oximetry The question of whether pulse oximetry measurements vary according to race has not been adequately studied, despite the wide use of this measure in clinical care. In t...

BackgroundAlthough inhaled therapy reduces exacerbations among patients with COPD, the effectiveness of providing inhaled treatment per risk stratification models remains unclear.Research questionAre inhaled regimens that align with the 2017 Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy associated with clinically important outcomes?Study design and methodsWe conducted secondary analyses of Long-term Oxygen Treatment Trial (LOTT) data. The trial enrolled patients with COPD with moderate resting or exertional hypoxemia between 2009 and 2015. Our exposure was the patient-reported inhaled regimen at enrollment, categorized as either aligning with, undertreating, or potentially overtreating per the 2017 GOLD strategy. Our primary composite outcome was time to death or first hospitalization for COPD. Additional outcomes included individual components of the composite outcome and time to first exacerbation. We generated multivariable Cox proportional hazard models across strata of GOLD-predicted exacerbation risk (high vslow) to estimate between-group hazard ratios for time to event outcomes. We adjusted models a priori for potential confounders, clustered by site.ResultsThe trial enrolled 738 patients (73.4%men; mean age, 68.8 years). Of the patients, 571 (77.4%) were low risk for future exacerbations. Of the patients, 233 (31.6%) reported regimens aligning with GOLD recommendations; most regimens (54.1%) potentially overtreated. During a 2.3-year median follow-up, 332 patients (44.9%) experienced the composite outcome. We found no difference in time to composite outcome or death among patients reporting regimens aligning with recommendations compared with undertreated patients. Among patients at low risk, potential overtreatment was associated with higher exacerbation risk (hazard ratio, 1.42; 95%CI, 1.09-1.87), whereas inhaled corticosteroid treatment was associated with 64%higher risk of pneumonia (incidence rate ratio, 1.64; 95%CI, 1.01-2.66).InterpretationAmong patients with COPD with moderate hypoxemia, we found no difference in clinical outcomes between inhaled regimens aligning with the 2017 GOLD strategy compared with those that were undertreated. These findings suggest the need to reevaluate the effectiveness of risk stratification model-based inhaled treatment strategies.

PURPOSE Medical school admissions committees are tasked with fulfilling the values of their institutions through careful recruitment. Making accurate predictions regarding enrollment behavior of admitted students is critical to intentionally formulating class composition and impacts long-term physician representation. The predictive accuracy and potential advantages of employing an enrollment predictive model in medical school admissions compared with expert human judgment have not been tested. METHOD The enrollment management-based predictive model previously generated using historical data was employed to provide a predicted enrollment percentage for each admitted student in the 2016-2017 application pool (N = 352). Concurrently, the human expert created a predicted enrollment percentage for each applicant while blinded to the values generated by the model. An absolute error for each applicant for both approaches was calculated. Statistical significance between approaches (expert vs. enrollment model) was assessed using t tests. RESULTS The enrollment management approach was noninferior to expert prediction in all cases (P < .05) with a superior correct classification rate (77.7% vs. 71.2%). When considering subgroup analyses for specific populations of potential importance in recruiting (underrepresented in medicine, female, and in-state applicants), the enrollment management predictions were statistically more accurate (P < .05). CONCLUSIONS Examining a single admitted class, the enrollment predictions using the enrollment management model were at least as accurate as the expert human estimates, and in specific populations of interest more accurate. This information can be readily exported for a real-time dashboard system to drive recruitment behaviors.

Hypogammaglobulinemia (serum IgG levels 7.0 g/L) has been associated with increased risk of COPD exacerbations but has not yet been shown to predict hospitalizations.To determine the relationship between hypogammaglobulinemia and the risk of hospitalization in patients with COPD.Serum IgG levels were measured on baseline samples from four COPD cohorts (n = 2,259): Azithromycin for Prevention of AECOPD (MACRO, n = 976); Simvastatin in the Prevention of AECOPD (STATCOPE, n = 653), Long-Term Oxygen Treatment Trial (LOTT, n = 354), and COPD Activity: Serotonin Transporter, Cytokines and Depression (CASCADE, n = 276). IgG levels were determined by immunonephelometry (MACRO; STATCOPE) or mass spectrometry (LOTT; CASCADE). The effect of hypogammaglobulinemia on COPD hospitalization risk was evaluated using cumulative incidence functions for this outcome and deaths (competing risk). Fine-Gray models were performed to obtain adjusted subdistribution hazard ratios (SHR) related to IgG levels for each study and then combined using a meta-analysis. Rates of COPD hospitalizations per person-year were compared according to IgG status.The overall frequency of hypogammaglobulinemia was 28.4%. Higher incidence estimates of COPD hospitalizations were observed among participants with low IgG levels compared with those with normal levels (Gray's test, P .001); pooled SHR (meta-analysis) was 1.29 (95% CI, 1.06-1.56, P = .01). Among patients with prior COPD admissions (n = 757), the pooled SHR increased to 1.58 (95% CI, 1.20-2.07, P .01). The risk of COPD admissions, however, was similar between IgG groups in patients with no prior hospitalizations: pooled SHR = 1.15 (95% CI, 0.86-1.52, P =.34). The hypogammaglobulinemia group also showed significantly higher rates of COPD hospitalizations per person-year: 0.48 ± 2.01 vs 0.29 ± 0.83, P .001.Hypogammaglobulinemia is associated with a higher risk of COPD hospital admissions.

In higher education, enrollment management has been developed to accurately predict the likelihood of enrollment of admitted students. This allows evidence to dictate numbers of interviews scheduled, offers of admission, and financial aid package distribution. The applicability of enrollment management techniques for use in medical education was tested through creation of a predictive enrollment model at the University of Michigan Medical School (U-M).U-M and American Medical College Application Service data (2006-2014) were combined to create a database including applicant demographics, academic application scores, institutional financial aid offer, and choice of school attended. Binomial logistic regression and multinomial logistic regression models were estimated in order to study factors related to enrollment at the local institution versus elsewhere and to groupings of competing peer institutions. A predictive analytic "dashboard" was created for practical use.Both models were significant at P.001 and had similar predictive performance. In the binomial model female, underrepresented minority students, grade point average, Medical College Admission Test score, admissions committee desirability score, and most individual financial aid offers were significant (P.05). The significant covariates were similar in the multinomial model (excluding female) and provided separate likelihoods of students enrolling at different institutional types.An enrollment-management-based approach would allow medical schools to better manage the number of students they admit and target recruitment efforts to improve their likelihood of success. It also performs a key institutional research function for understanding failed recruitment of highly desirable candidates.

BACKGROUND Long-term treatment with supplemental oxygen has unknown efficacy in patients with stable chronic obstructive pulmonary disease (COPD) and resting or exercise-induced moderate desaturation. METHODS We originally designed the trial to test whether long-term treatment with supplemental oxygen would result in a longer time to death than no use of supplemental oxygen among patients who had stable COPD with moderate resting desaturation (oxyhemoglobin saturation as measured by pulse oximetry [Spo2], 89 to 93%). After 7 months and the randomization of 34 patients, the trial was redesigned to also include patients who had stable COPD with moderate exercise-induced desaturation (during the 6-minute walk test, Spo2 ≥80% for ≥5 minutes and

Medical school admissions interviews are used to assess applicants’ nonacademic characteristics as advocated by the Association of American Medical Colleges’ Advancing Holistic Review Initiative. The objective of this study is to determine whether academic metrics continue to significantly influence interviewers’ scores in holistic processes by blinding interviewers to applicants’ undergraduate grade point averages (uGPA) and Medical College Admission Test (MCAT). This study examines academic and demographic predictors of interview scores for two applicant cohorts at the University of Michigan Medical School. In 2012, interviewers were provided applicants’ uGPA and MCAT scores; in 2013, these academic metrics were withheld from interviewers’ files. Hierarchical regression analysis was conducted to examine the influence of academic and demographic variables on overall cohort interview scores. When interviewers were provided uGPA and MCAT scores, academic metrics explained more variation in interview scores (7.9%) than when interviewers were blinded to these metrics (4.1%). Further analysis showed a statistically significant interaction between cohort and uGPA, indicating that the association between uGPA and interview scores was significantly stronger for the 2012 unblinded cohort compared to the 2013 blinded cohort (β = .573, P < .05). By contrast, MCAT scores had no interactive effects on interviewer scores. While MCAT scores accounted for some variation in interview scores for both cohorts, only access to uGPA significantly influenced interviewers’ scores when looking at interaction effects. Withholding academic metrics from interviewers’ files may promote assessment of nonacademic characteristics independently from academic metrics.

Problem Most medical schools have either retained a traditional admissions interview or fully adopted an innovative, multisampling format (e.g., the multiple mini-interview) despite there being advantages and disadvantages associated with each format. Approach The University of Michigan Medical School (UMMS) sought to maximize the strengths associated with both interview formats after recognizing that combining the two approaches had the potential to capture additional, unique information about an applicant. In September 2014, the UMMS implemented a hybrid interview model with six, 6-minute short-form interviews-highly structured scenario-based encounters-and two, 30-minute semistructured long-form interviews. Five core skills were assessed across both interview formats. Outcomes Overall, applicants and admissions committee members reported favorable reactions to the hybrid model, supporting continued use of the model. The generalizability coefficients for the six-station short-form and the two-interview long-form formats were estimated to be 0.470 and 0.176, respectively. Different skills were more reliably assessed by different interview formats. Scores from each format seemed to be operating independently as evidenced through moderate to low correlations (r = 0.100-0.403) for the same skills measured across different interview formats; however, after correcting for attenuation, these correlations were much higher. Next steps This hybrid model will be revised and optimized to capture the skills most reliably assessed by each format. Future analysis will examine validity by determining whether short-form and long-form interview scores accurately measure the skills intended to be assessed. Additionally, data collected from both formats will be used to establish baselines for entering students' competencies.

In the event of a virulent influenza pandemic, certain resources including ventilators, antibiotics, vaccines, oxygen, hospital beds, and antiviral medications will need to be carefully allocated. It is essential that scarce resources are allocated in an ethical manner taking into account the patient’s individual right to competent care and a population’s right to the fair distribution of potentially life-saving treatments. This article summarizes the ethical basis for distributing scarce resources and the rationale for establishing a hospital-based Scarce Resource Allocation Committee, a system of multiple triage officers, and a Clinical Review Committee.

Treatment and prognoses of diffuse parenchymal lung diseases (DPLDs) varies by diagnosis. Obtaining a uniform diagnosis among observers is difficult.Evaluate diagnostic agreement between academic and community-based physicians for patients with DPLDs, and determine if an interactive approach between clinicians, radiologists, and pathologists improved diagnostic agreement in community and academic centers.Retrospective review of 39 patients with DPLD. A total of 19 participants reviewed cases at 2 community locations and 1 academic location. Information from the history, physical examination, pulmonary function testing, high-resolution computed tomography, and surgical lung biopsy was collected. Data were presented in the same sequential fashion to three groups of physicians on separate days.Each observer's diagnosis was coded into one of eight categories. A kappa statistic allowing for multiple raters was used to assess agreement in diagnosis. Interactions between clinicians, radiologists, and pathologists improved interobserver agreement at both community and academic sites; however, final agreement was better within academic centers (kappa = 0.55-0.71) than within community centers (kappa = 0.32-0.44). Clinically significant disagreement was present between academic and community-based physicians (kappa = 0.11-0.56). Community physicians were more likely to assign a final diagnosis of idiopathic pulmonary fibrosis compared with academic physicians.Significant disagreement exists in the diagnosis of DPLD between physicians based in communities compared with those in academic centers. Wherever possible, patients should be referred to centers with expertise in diffuse parenchymal lung disorders to help clarify the diagnosis and provide suggestions regarding treatment options.

Current guidelines recommend that the clinician, radiologist, and pathologist work together to establish a diagnosis of idiopathic interstitial pneumonia. Three clinicians, two radiologists, and two pathologists reviewed 58 consecutive cases of suspected idiopathic interstitial pneumonia. Each participant was provided information in a sequential manner and was asked to record their diagnostic impression and level of confidence at each step. Interobserver agreement improved from the beginning to the end of the review. After the presentation of histopathologic information, radiologists changed their diagnostic impression more often than did clinicians. In general, as more information was provided the confidence level for a given diagnosis improved, and the diagnoses rendered with a high level of confidence were more likely congruent with the final pathologic consensus diagnosis. The final consensus pathologist diagnosis was idiopathic pulmonary fibrosis in 30 cases. Clinicians identified 75% and radiologists identified 48% of these cases before presentation of the histopathologic information. Histopathologic information has the greatest impact on the final diagnosis, especially when the initial clinical/radiographic diagnosis is not idiopathic pulmonary fibrosis. We conclude that dynamic interactions between clinicians, radiologists, and pathologists improve interobserver agreement and diagnostic confidence.

Idiopathic pulmonary fibrosis (IPF) is typically a fatal disease that fails to respond to medical therapy. For these patients lung transplantation offers the promise of improved quality and duration of life. The initial reports of successful transplantation for IPF date back to the mid-1980s although recent data suggest IPF patients make up nearly 20% of all single lung transplants. The survival rates following lung transplantation for IPF are estimated at 67% for 1 year, 52% for 3 years, and 35% for 5 years. Mortality rates following lung transplantation for IPF are higher than emphysema, but are generally comparable to primary pulmonary hypertension. Given the relatively high mortality following transplant the decision of when to transplant a patient is of paramount importance. Although individual patients differ, generalizations predicting a poor prognosis include the diagnosis of usual interstitial pneumonia (UIP), a forced vital capacity or total lung capacity of less than 65% predicted, a diffusion capacity for carbon monoxide (DL(CO)) less than 45% of predicted, and the presence of extensive honeycombing on high-resolution computed tomographic scans. The presence of any of these features should prompt the patient and physician to consider lung transplantation as a potential therapeutic modality. Patients with interstitial lung disease related to collagen vascular diseases or other causes need to be considered on an individual basis; their prognosis is usually better than patients with IPF, and the potential for systemic involvement may preclude listing for lung transplantation.

Idiopathic pulmonary fibrosis (IPF) is associated with significant morbidity and mortality despite aggressive therapy. Thirty-eight patients with biopsy-proven IPF were studied to identify pretreatment features that could be used to predict short-term improvement in pulmonary function and improved longer term survival. In all patients, a pretreatment clinical (dyspnea), radiographic (chest radiograph), and physiologic (pulmonary function including exercise saturation) score was generated (CRP). A high-resolution CT scan (HRCT) was independently scored by four radiologists for ground glass (CT-alv) and linear opacity (CT-fib) on a scale of 0-4. Open lung biopsy samples were scored for cellular infiltration, interstitial fibrosis, desquamation, and granulation by an experienced pulmonary pathologist. All patients were treated with 3 mo of high-dose steroids and the CRP scoring repeated. Patients were divided into three groups: responders with a greater than 10-point drop in CRP (n = 10); stable with +/- 10 point change in CRP (n = 14); and nonresponders with > 10 point rise in CRP or death (n = 14). Those responding to steroids were treated for 18 mo in a tapering fashion. In all others, steroids were tapered quickly and oral cyclophosphamide prescribed. Responders (10 of 38) had a lower age (45.1+/-4.3 yr) than nonresponders (61.4+/-3.5 yr) or those remaining stable (53.1+/-3.3 yr) (p = 0.01). Pretreatment CRP was higher in responders (58.8+/-5.6) than nonresponders (40.5+/-4.7) or stable individuals (37.6+/-4.7) (p = 0.01). Cellular infiltration score of the open lung biopsies was higher in responders (7.6+/-0.6) than stable individuals (5.7+/-0.5) (p = 0.04). The CT-alv scores were higher and CT-fib scores were lower in responders than nonresponders. Receiver operating curve (ROC) analysis was employed to identify pretreatment features of longer term survival (follow-up of 29.1+/-2.3 mo). Only CT-fib (p = 0.009) and pathology fibrosis score (p = 0.03) were able to predict mortality. A pretreatment CT-fib score > or = 2.0 demonstrated 80% sensitivity and 85% specificity in predicting survival. Those patients who did not respond to initial steroid therapy demonstrated a worse long-term survival and greater likelihood of decreased pulmonary function. We demonstrate that pretherapy pulmonary function, pathologic and radiographic parameters are different in individuals who respond to initial prednisone therapy. Only HRCT imaging and pathologic fibrosis were able to reliably predict long-term survival in patients with biopsy-proven IPF.

We are currently in the midst of the 2009 H1N1 pandemic, and a second wave of flu in the fall and winter could lead to more hospitalizations for pneumonia. Recent pathologic and historic data from the 1918 influenza pandemic confirms that many, if not most, of the deaths in that pandemic were a result of secondary bacterial pneumonias. This means that a second wave of 2009 H1N1 pandemic influenza could result in a widespread shortage of antibiotics, making these medications a scarce resource. Recently, our University of Michigan Health System (UMHS) Scarce Resource Allocation Committee (SRAC) added antibiotics to a list of resources (including ventilators, antivirals, vaccines) that might become scarce during an influenza pandemic. In this article, we summarize the data on bacterial pneumonias during the 1918 influenza pandemic, discuss the possible impact of a pandemic on the University of Michigan Health System, and summarize our committee's guiding principles for allocating antibiotics during a pandemic.

Rationale: The predictive value of longitudinal change in BODE (Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity) index has received limited attention. We hypothesized that decrease in a modified BODE (mBODE) would predict survival in National Emphysema Treatment Trial (NETT) patients. Objectives: To determine how the mBODE score changes in patients with lung volume reduction surgery versus medical therapy and correlations with survival. Methods: Clinical data were recorded using standardized instruments. The mBODE was calculated and patient-specific mBODE trajectories during 6, 12, and 24 months of follow-up were estimated using separate regressions for each patient. Patients were classified as having decreasing, stable, increasing, or missing mBODE based on their absolute change from baseline. The predictive ability of mBODE change on survival was assessed using multivariate Cox regression models. The index of concordance was used to directly compare the predictive ability of mBODE and its separate components. Measurements and Main Results: The entire cohort (610 treated medically and 608 treated surgically) was characterized by severe airflow obstruction, moderate breathlessness, and increased mBODE at baseline. A wide distribution of change in mBODE was seen at follow-up. An increase in mBODE of more than 1 point was associated with increased mortality in surgically and medically treated patients. Surgically treated patients were less likely to experience death or an increase greater than 1 in mBODE. Indices of concordance showed that mBODE change predicted survival better than its separate components. Conclusions: The mBODE demonstrates short- and intermediate-term responsiveness to intervention in severe chronic obstructive pulmonary disease. Increase in mBODE of more than 1 point from baseline to 6, 12, and 24 months of follow-up was predictive of subsequent mortality. Change in mBODE may prove a good surrogate measure of survival in therapeutic trials in severe chronic obstructive pulmonary disease. Clinical trial registered with www.clinicaltrials.gov (NCT 00000606).

Respiratory compromise is the leading cause of morbidity and mortality in patients with neuromuscular and neurologic disease, and in elderly patients, who have a reduced pulmonary reserve from deterioration of the respiratory system associated with the normal aging process. Although the otherwise healthy older patient is normally asymptomatic, their pulmonary reserve is further compromised during stressful situations such as surgery, pneumonia, or exacerbation of a comorbid condition. The inability to effectively remove retained secretions and prevent aspiration contribute to this compromise. Although no secretion-management therapies are identified as having specific application to the elderly, clinicians must be attentive and understand the needs of the elderly to prevent the development of respiratory compromise. Patients with neuromuscular disease often can not generate an effective cough to mobilize and evacuate secretions. Respiratory muscle training, manual cough assistance, mechanical cough assistance, high-frequency chest wall compression, and intrapulmonary percussive ventilation have each been suggested as having potential benefit in this population. Although strong evidence supporting the benefit of these therapies is lacking, clinicians must be guided as to whether there is a pathophysiologic rationale for applying the therapy, whether adverse effects are associated with the therapy, the cost of therapy, and whether the patient prefers a given therapy.

Evaluation and diagnosis of obstructive lung disease call for careful history taking to distinguish asthma from chronic obstructive pulmonary disease (COPD). A history of atopy and intermittent, reactive symptoms points toward a diagnosis of asthma, whereas smoking and advanced age are more indicative of COPD. Clinical features such as cough and wheezing, especially in light of patient history, can be suggestive but are not definitive. Spirometry, usually performed in the primary care setting, is the key diagnostic tool that distinguishes patients with asthma from patients with COPD. In this article, the authors outline an approach to differential diagnosis of asthma and COPD that should result in better evaluation, therapy, and quality of life for these patients.