The Effect of Aerosol Saline on Laboratory-Induced Dyspnea.

PURPOSE: In the 'placebo arm' of a recent study, we found that aerosol saline (sham treatment) produced substantial relief of laboratory-induced dyspnea (Breathing discomfort-BD) in nearly half the subjects. The sham intervention included a physiological change, and instructions to subjects could have produced expectation of dyspnea relief. In the present study, we attempted to discover whether the response to sham aerosol was driven by behavioral or physiological aspects of the intervention. METHODS: Dyspnea (air hunger) was evoked by constraining tidal volume during graded hypercapnia. We measured [Formula: see text] versus BD relationship before and after aerosol saline. To minimize subjects' expectations of dyspnea relief, participants were clearly instructed that we would only deliver saline aerosol. In Protocol 1, we delivered aerosol saline with a ventilator (mimicking our prior study); in Protocol 2, we delivered aerosol without a ventilator. RESULTS: Administration of aerosol saline had little effect on BD in this group of subjects with one exception: one subject experienced appreciable reduction in BD in Protocol 1. This treatment effect was less in Protocol 2. The two most likely explanations are (a) that procedures surrounding ventilator administration of aerosol produced a psychological placebo treatment effect even though the subject knew a drug was not given; (b) there were behavioral changes in breathing undetected by our measurements of respiratory flow and volume that altered the subjects comfort. CONCLUSION: When the expectation of treatment effect is minimized, a significant reduction in dyspnea in response to saline placebo is uncommon but not impossible.

Static end-expiratory and dynamic forced expiratory tracheal collapse in COPD.

AIM: To determine the range of tracheal collapse at end-expiration among chronic obstructive pulmonary disease (COPD) patients and to compare the extent of tracheal collapse between static end-expiratory and dynamic forced-expiratory multidetector-row computed tomography (MDCT). MATERIALS AND METHODS: After institutional review board approval and obtaining informed consent, 67 patients meeting the National Heart, Lung, and Blood Institute (NHLBI)/World Health Organization (WHO) Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD were sequentially imaged using a 64-detector-row CT machine at end-inspiration, during forced expiration, and at end-expiration. Standardized respiratory coaching and spirometric monitoring were employed. Mean percentage tracheal collapse at end-expiration and forced expiration were compared using correlation analysis, and the power of end-expiratory cross-sectional area to predict excessive forced-expiratory tracheal collapse was computed following construction of receiver operating characteristic (ROC) curves. RESULTS: Mean percentage expiratory collapse among COPD patients was 17 ± 18% at end-expiration compared to 62 ± 16% during forced expiration. Over the observed range of end-expiratory tracheal collapse (approximately 10-50%), the positive predictive value of end-expiratory collapse to predict excessive (≥80%) forced expiratory tracheal collapse was <0.3. CONCLUSION: COPD patients demonstrate a wide range of end-expiratory tracheal collapse. The magnitude of static end-expiratory tracheal collapse does not predict excessive dynamic expiratory tracheal collapse.

Early sexual initiation and subsequent sex-related risks among urban minority youth: the reach for health study.

CONTEXT: Since the 1980s, the age at which U.S. teenagers, especially minority youth, begin having sex has decreased. There is limited information on the relationship between early sexual initiation and subsequent risky sexual behaviors. METHODS: A sample of 1,287 urban minority adolescents completed three surveys in seventh and eighth grade, and 970 completed a follow-up in 10th grade. Logistic regression was used to test the effects of timing of initiation on 10th-grade sexual behaviors and risks, adjusting for gender, ethnicity and age. RESULTS: At baseline, 31% of males and 8% of females reported sexual initiation; by the 10th grade, these figures were 66% and 52%, respectively. Recent intercourse among males increased from 20% at baseline to 39% in eighth grade; 54% reported recent sex and 6% had made a partner pregnant by 10th grade. Among females, recent intercourse tripled from baseline to eighth grade (5% to 15%); 42% reported recent sex and 12% had been pregnant by grade 10. Early initiators had an increased likelihood of having had multiple sex partners, been involved in a pregnancy, forced a partner to have sex, had frequent intercourse and had sex while drunk or high. There were significant gender differences for all outcomes except frequency of intercourse and being drunk or high during sex. CONCLUSIONS: Minority adolescents who initiate sexual activity early engage in behaviors that place them at high risk for negative health outcomes. It is important to involve parents and schools in prevention efforts that address sexual initiation in early adolescence and that target youth who continue to place themselves and their partners at risk.

Reductions in STD infections subsequent to an STD clinic visit. Using video-based patient education to supplement provider interactions.

BACKGROUND AND OBJECTIVES: Video-based patient education has been effective in a variety of clinical settings. The authors studied the efficacy of a video-based educational intervention in an inner-city public sexually transmitted diseases (STD) clinic. GOAL: To evaluate the efficacy of video-based patient education in reducing STD infections subsequent to a clinic visit. DESIGN: African-American and Hispanic men attending a large public STD clinic were assigned at random to either an experimental video-based educational intervention or a control condition in which they received regular clinic services. Patients in the experimental group were exposed to video-based interventions that provided information about STDs and their prevention, portrayed positive attitudes about condom use, and modeled appropriate strategies for encouraging condom use in different sexual relationships. During 1992, 2,004 subjects were tracked for an average of 17 months through the New York City STD surveillance database for the occurrence of new STD infections. RESULTS: The overall rate of new infection among male STD clinic patients was 24.2%. Rate of new infection was significantly lower among those exposed to video-based prevention education than among controls (22.5% compared with 26.8%, p < .05). Subjects reporting multiple sex partners had a significantly higher new infection rate but also experienced the greatest impact of educational intervention. There was a 32.2% new infection rate among high-risk controls compared with a 24.8% rate among high-risk intervention groups (p < 0.025). CONCLUSION: Results of this randomized clinical trial indicate that using video-based patient education to supplement regular STD clinic services and provider interactions can be effective in reducing rates of new STD infection, particularly among those at greatest risk.

Firearm deaths among children and youth.

Nationally, homicide and suicide are the 2nd and 3rd leading causes of death among children and youth under the age of 21. Sixteen to 19-year-olds now have the highest rate of handgun victimization among all age groups. The firearm suicide rate for White males is over 4 times higher than the rate for African American males, whereas the firearm homicide rate is over 9 times higher for African American males. Almost half of all deaths among African American male teenagers now involve firearms. Multiple steps, both short- and long-term, need to be taken to reduce firearm death rates among children and youth. Some of the possible methods to do so are discussed.

Barriers to condom use in primary and nonprimary relationships among Hispanic STD clinic patients.

PIP: Some programs designed to reduce the spread of AIDS and other STDs encourage consistent condom use among sexually active, at-risk individuals. A random sample of 283 Hispanic men and women seeking services at a public STD clinic in New York City were surveyed in an examination of differences in their attitudinal patterns, normative beliefs, and practices related to condom use with primary and nonprimary sex partners. 60% of the participants were male. The group was of mean age 30.9 years, with 46% having graduated from high school. 44.5% were born in the US, although 73.8% had lived in mainland US for the previous ten years or longer. 52.7% were single, 19.8% married, and the remaining 27.5% were either divorced, separated, or widowed. Only 3.2% of men and women reported having same-sex relationships, although the authors suggest that the respondents may have underreported the extent of their bisexual and homosexual behavior. 58.3% of men and 53.3% of women reported having had a prior STD, 82.2% of men and 74.8% of women had experience using a condom, and 31.3% of men and 13.3% of women reported having nonprimary partners. Both the men and women report that they are more likely to use condoms in nonprimary than primary relationships and that they perceive fewer barriers to doing so. Issues related to trust and social acceptability are more salient in primary relationships. Interventions to promote condom use among Hispanics must acknowledge the different psychosocial influences upon condom use in different relationships and target the specific attitudinal and behavioral changes desired.^ieng

The effectiveness of video-based interventions in promoting condom acquisition among STD clinic patients.

GOAL OF THIS STUDY: This study examined the effectiveness of video-based patient education interventions on promoting condom use among men and women seeking services at a large public STD clinic in New York City. METHODS: Culturally sensitive video-based interventions designed to promote safer sex behaviors were evaluated in a randomized study of black and Hispanic male and female STD clinic patients. Subjects (n = 1,653) were randomly assigned to one of three groups: 1) control, 2) video viewing, and 3) video viewing followed by participation in an interactive group session led by a trained facilitator. The authors examined 1) the effectiveness of interventions in increasing STD and condom-related knowledge, positive attitudes about condoms, human immunodeficiency virus/STD risk perceptions, and self-efficacy and 2) the relationships among these variables, level of intervention, and condom acquisition, a behavioral measure of condom use. RESULTS: Compared with a control group, subjects assigned to video viewing demonstrated greater knowledge about condoms and STDs, more positive attitudes about condom use, increased human immunodeficiency virus/STD risk perceptions, greater self-efficacy, and higher rates of condom acquisition. Subjects assigned to video viewing followed by interactive sessions demonstrated still further increases in risk perceptions, self-efficacy, and condom acquisition, but not in knowledge or condom attitudes. A significant proportion of the association between the behavioral outcome of condom acquisition and level of intervention is attributable to the impact of interventions on risk perception and self-efficacy. CONCLUSIONS: Based on extensive formative research that identified barriers to safer sex behaviors, video-based interventions were developed to promote condom use among black and Hispanic men and women attending STD clinics. Designed to be integrated into clinic services, these interventions help improve knowledge, promote positive attitudes about condoms, and increase condom acquisition among individuals at high risk of acquiring and transmitting human immunodeficiency virus infection and other STDs.

PIP: In 1992 in New York City, 1653 Black and Hispanic men and women at the Morrisania STD Clinic in the South Bronx were randomly assigned to one of three groups [routine clinic services (control); video viewing (video titles: "Porque Si" for Hispanics and "Let's Do Something Different" for Blacks); and video viewing plus an interactive session] for a study assessing the effectiveness of video interventions in promoting condom acquisition. Condom acquisition was a proxy for condom use. STD patients in the video viewing groups increased their knowledge about condom use and STDs/AIDS (p 0.001). They had more positive attitudes about condom use (p = 0.0021), perceived themselves at a greater risk of contracting an STD or AIDS (p = 0.0314), and had higher levels of self-efficacy (p 0.0001). The video viewing plus interactive session group made further gains in measures of risk perception and self-efficacy (p 0.01) but not in knowledge or positive condom attitudes. 27.4% of the video viewing group and 22% of the routine clinic service group redeemed coupons for condoms at a neighborhood pharmacy compared to 41.4% of those in the video viewing plus interactive session group (p 0.0001). The multiple logistic regression analysis confirmed that scores in knowledge, positive attitudes, perceived risk, and self-efficacy were greater among the video viewing group than the controls (odds ratio [OR] = 1.11, 1.07, 1.10, and 1.08, respectively; p 0.01). When comparing the video viewing group and the video viewing plus interactive session group, there were positive interactions between intervention and risk perception (OR = 1.08) and self-efficacy (OR = 1.07) (p 0.01) but not between intervention and positive condom attitudes. There was a negative interaction between intervention and knowledge for the video viewing plus interactive session group (OR = 0.92; p 0.01). These findings suggest that culturally sensitive video-based interventions improve knowledge, promote positive condom attitudes, and increase condom acquisition among persons at high risk of STDs and AIDS.

Predictors of condom acquisition after an STD clinic visit.

Data from a survey of 691 men and women who made patient visits to an inner-city, sexually transmitted disease (STD) clinic and were given coupons to redeem for condoms at a neighborhood pharmacy show that only 22% of the sample did so. Gender, ethnicity, marital status and education were not significant predictors of whether study participants redeemed their coupons. Factors that significantly predicted coupon redemption included the extent of acculturation and age, with those who were older and less acculturated more likely to do so. Other significant factors were having a primary sexual partner and having had more than one sexual partner in the last month; having ever had an STD was negatively associated with coupon redemption. A perception of being at high STD risk and a favorable attitude about condoms also significantly predicted condom acquisition. All these variables, except for attitude toward condoms and a history of an STD, remained significant when entered into a logistic regression controlling for the influence of all independently significant predictors.

STD prevention and the challenge of gender and cultural diversity: knowledge, attitudes, and risk behaviors among black and Hispanic inner-city STD clinic patients.

BACKGROUND AND OBJECTIVES: This study describes gender and cultural differences in sex-related risk behaviors, knowledge, and attitudes among black and Hispanic men and women seeking services at an STD clinic in the South Bronx. STUDY DESIGN: Survey instruments were administered to 3,348 men and women selected as a proportionate random sample of clinic patients registered from January through December 1992. RESULTS: There were significant differences in risk behaviors, knowledge about AIDS and STDs, and attitudes related to condom use among men and women who sought services at this large inner-city clinic. Across groups, the majority of subjects had a history of prior STDs and previously had been treated at a STD clinic. Overall levels of knowledge were high, with the exception of specific issues related to condom use and STD symptoms. Gender and cultural differences were most apparent in sex practices, experience with condoms, and attitudes concerning the use of condoms in relationships. CONCLUSIONS: These data indicate the need to design clinic prevention programs that reflect the diversity of gender and culturally based attitudes, knowledge, and behaviors within inner-city populations. Minority men and women who seek services at STD clinics are known to be at high risk of HIV infection and other sexually transmitted diseases. Yet providing all members of this patient population with the same prevention messages is not sufficient; differences in sex practices, educational needs, and concerns about adopting safer sex behaviors must be taken into account. This study underscores how important it is for clinics to develop the multiple interventions necessary to provide patients with the specific information and skills they need--beyond admonishments to avoid risky sex and use condoms--and for clinic staff to be trained in providing education that is gender and culturally appropriate.

Indications for preoperative pulmonary function testing.

Atelectasis, hypoxemia, pneumonia, and respiratory failure are pulmonary complications that can follow surgical procedures. This article discusses controversies surrounding the use of preoperative pulmonary function testing to identify high-risk surgical candidates. Physiologic assessments based upon the nature of the contemplated procedure are recommended.

Aerosol-derived lung morphometry: comparisons with a lung model and lung function indexes.

This study evaluated the ability of aerosol-derived lung morphometry to noninvasively probe airway and acinar dimensions. Effective air-space diameters (EAD) were calculated from the time-dependent gravitational losses of 1-microns particles from inhaled aerosol boluses during breath holding. In 17 males [33 +/- 7 (SD) yr] the relationship between EAD and volumetric penetration of the bolus into the lungs (Vp) could be expressed by the linear power-law function, log (EAD) alpha beta log (Vp). Our EAD values were consistent with Weibel's symmetric lung model A for small airways and more distal air spaces. As lung volume increased from 57 to 87% of total lung capacity (TLC), EAD at Vp of 160 and 550 cm3 increased 70 and 41%, respectively. At 57% TLC, log (EAD) at 160 cm3 was significantly correlated with airway resistance (r = -0.57, P less than 0.0204) but not with forced expired flow between 25 and 75% of vital capacity. Log (EAD) at 400 cm3 was correlated with deposition of 1-micron particles (r = -0.73, P less than 0.0009). We conclude that aerosol-derived lung morphometry is a responsive noninvasive probe of peripheral air-space diameters.

The flow-ratio index. An approach for measuring the influence of age and cigarette smoking on maximum expiratory flow-volume curve configuration.

A forced expiratory flow ratio, derived from the average slope of the maximum expiratory flow-volume (MEFV) curve over a specified volume interval, was examined in healthy asymptomatic cigarette smokers and nonsmokers. This index was developed to have the properties that it would be (1) simple to calculate, (2) less effort dependent than indices that incorporate peak flow, and (3) free of influence from the configurational detail and noise frequently occurring at higher lung volumes on MEFV curves. Forced expired vital capacity maneuvers were performed by participants in a worksite health promotion program. Data from asymptomatic individuals with normal pulmonary function were analyzed for 49 cigarette smokers and 52 nonsmokers; 25 individuals had MEFV curves collected twice over a one-year interval. The ratio of flow derived from an average MEFV slope to instantaneous flow was calculated over the lower half of the vital capacity. Flow ratios were expressed as a percentage of the instantaneous flow at 75 percent of the expired vital capacity (FR75). This ratio was reproducible from year 1 to year 2 (r = 0.86, p less than 0.0001). Furthermore, the FR75 was well correlated with age among cigarette smokers and nonsmokers (r = 0.68 and 0.63 respectively). The slope of the least squares regression equation relating FR75 to age was significantly greater among smokers than nonsmokers (2.90 percent per year vs. 1.73 percent per year, p less than 0.025). While there was a significant interactive influence of age and total pack-years on the FR75 (F = 2.91, p = 0.02), this index did not differ systematically by gender. We conclude that the FR25 is a more sensitive index of altered lung function in cigarette smokers than are results of conventional pulmonary function.

Indications for pulmonary function testing.

STUDY OBJECTIVE: To critically assess original studies evaluating the role of preoperative pulmonary function testing in predicting postoperative outcomes. DESIGN: MEDLINE search of English-language articles from 1966 to 1987 using the following medical subjects headings respiratory function tests, lung, lung diseases, and preoperative care. MEASUREMENTS AND MAIN RESULTS: Relevant studies were subdivided by operative site. We included only studies for which we could determine pre- and post-test probabilities of morbidity, mortality, sensitivity, and specificity. Preoperative pulmonary function testing was found to have measureable benefit in predicting outcome in lung resection candidates. In selected patients, split perfusion lung scanning and pulmonary exercise testing appeared to be useful. Confirmation of these reports is necessary before these preoperative tests can be routinely recommended. In studies of upper abdominal surgery, spirometry and arterial blood gas analysis did not consistently have measureable benefit in identifying patients at increased risk for postoperative pneumonia, prolonged hospitalization, and death. Studies of preoperative testing for other patients, including those having coronary artery bypass grafting, lacked adequate data for meaningful analysis. CONCLUSIONS: Preoperative pulmonary function testing helps clinicians to make decisions on management of lung resection candidates. Although many studies of patients before abdominal surgery have focused on the utility of preoperative pulmonary function testing, methodologic difficulties undermine the validity of their conclusions. The impact of testing on care of other preoperative patients is even less clear because of poor study design and insufficient data. Therefore, further investigation is necessary before a consensus can be reached on the role of preoperative pulmonary function testing in evaluating patients before all surgical procedures except lung resection.

Abnormal airway function in individuals with the acquired immunodeficiency syndrome.

Pulmonary function test results of individuals with the acquired immunodeficiency syndrome (AIDS) were analyzed to determine the prevalence of abnormally low forced expiratory flow rates and bronchial hyperreactivity. Of 99 individuals with AIDS, a total of 44 (44 percent) had either low forced expiratory flow rates or a significant response to inhaled bronchodilator. Thirty-one (31 percent) individuals exhibited significant improvement in airflow rates after bronchodilator inhalation, while 33 (33 percent) had low flow rates. Twenty (20 percent) individuals had both low flow rates and a significant response to bronchodilator. In 83 percent of symptomatic individuals treated with bronchodilators there was clinical improvement. Thus, we conclude that abnormally low forced expiratory flow rate with or without bronchial hyperreactivity is a common and treatable complication of AIDS.

Diminished perception of inspiratory-resistive loads in insulin-dependent diabetics.

Diabetes mellitus is known to be associated with impaired perception of sensory input from organs such as the heart. To determine whether diabetics have a diminished ability to perceive respiratory sensations, we compared the abilities of patients with insulin-dependent diabetes (n = 17) and nondiabetic controls (n = 13) to detect inspiratory-resistive loads. The subjects were evaluated as they breathed through a tube-manifold apparatus with resistance that was varied randomly. They indicated whenever they perceived increased resistance to inspiration. The threshold for detecting added inspiratory resistance was expressed as a fraction of the background resistance of the subject plus that of the apparatus. This fraction, known as the Weber fraction, was 0.53 +/- 0.19 (mean +/- SD) in diabetics with neuropathy, 0.38 +/- 0.24 in diabetics without neuropathy, and 0.29 +/- 0.15 in nondiabetic controls. The differences in the mean value of the Weber fraction among the three groups were significantly different from zero (F = 4.57, P less than 0.025). There was not a significant correlation between the Weber fraction and age, degree of autonomic dysfunction, pulmonary function, cigarette smoking, or degree of diabetic control. The Weber fraction correlated with the duration of diabetes (r = 0.57, P less than 0.02). We conclude that patients with insulin-dependent diabetes may have an impaired ability to perceive inspiratory-resistive loads. This increased threshold for the perception of respiratory sensations may lead to delayed recognition of pulmonary disease in diabetics.

In vivo estimation of tracheal distensibility and hysteresis in normal adults.

We used the acoustic reflection technique to measure the cross-sectional area of tracheal and bronchial airway segments of eight healthy adults. We measured airway area during a slow continuous expiration from total lung capacity (TLC) to residual volume (RV) and during inspiration back to TLC. Lung volume and esophageal pressure were monitored continuously during this quasi-static, double vital capacity maneuver. We found that 1) the area of tracheal and bronchial segments increases with increasing lung volume and transpulmonary pressure, 2) the trachea and bronchi exhibit a variable degree of hysteresis, which may be greater or less than that of the lung parenchyma, 3) extrathoracic and intrathoracic tracheal segments behaved as if they were subjected to similar transmural pressure and had similar elastic properties, and 4) specific compliance (means +/- SE) for the intrathoracic and bronchial segments, calculated with the assumption that transmural pressure is equal to the transpulmonary pressure, was significantly (P less than 0.05) smaller for the intrathoracic segment than for the bronchial segment: (2.1 +/- 2.0) X 10(-3) cmH2O-1 vs. (9.1 +/- 2.1) X 10(-3) cmH2O-1. Direct measurements of airway area using acoustic reflections are in good agreement with previous estimates of airway distensibility in vivo, obtained by radiography or endoscopy.

Accuracy of spirometric and flow-volume indices obtained by digitizing volume-time tracings.

We tested the accuracy of a new system for deriving standard spirometric indices, maximal expiratory flow rates, and slope ratios from volume-time tracings. A computer-based technique employing a hand-operated cursor was used to put discrete values of volume and time into a memory array. Spirometric values obtained on 102 subjects using the computer system were compared with the corresponding "hand-read" values. The difference between the 2 measuring techniques were not significant for the FVC, the FEV75, and the FEF25-75; however, the average FEV1 differed by 6.7 ml (SD, 20.3 ml), which was significant. In addition, 10 subjects performed FVC maneuvers through a spirometer and flowmeter connected in series. Flows and slope ratios obtained from the volume-time tracings were compared with those obtained directly from the flowmeter. There was a high degree of correlation between the 2 types of flow measurements (r = 0.989), whereas slope ratios were less well correlated (r = 0.589). Configurational detail such as the presence of "bumps" on slope ratio versus volume plots were recovered with the computer technique. Using this new system, it is possible for 1 operator to process 10 to 12 sets of spirometry tracings per hour.

Changes in flow-volume curve configuration with bronchoconstriction and bronchodilation.

Changes in the configuration of maximum expiratory flow-volume (MEFV) curves following mild degrees of bronchodilation or bronchoconstriction were studied in five normal and five asthmatic subjects. In a volume-displacement plethysmograph, MEFV curves were performed before and after inhalation of aerosolized isoproterenol (I) or histamine (H). Five filtered MEFV curves were averaged, and slope ratio vs. volume (SR-V) plots were obtained from averaged curves. Following I, maximal flows at 75% of the vital capacity (VC) were decreased in asthmatics but not in normal subjects. Flows at 50 and 25% of the VC increased in normal subjects and asthmatics, whereas VC's were unchanged. In asthmatics, sudden large decreases in flow (bumps) occurred at lower lung volumes following I. H reduced flows over the entire VC, with greater reductions occurring in asthmatics than in normals, particularly at low lung volumes. In asthmatics, VC was slightly reduced, and bumps in MEFV curve configuration occurred at higher lung volumes or were abolished entirely following H. A reduction in the amount of configurational detail appreciable in MEFV curves following histamine in asthmatics was best seen in SR-V plots. Following H, SR's decreased regularly with decreasing lung volume in all the asthmatics but in none of the normals. This was the single most striking finding of this study. Mild I- and H-induced perturbations of airway bronchomotor tone produced small but consistent changes in MEFV curve configuration.(ABSTRACT TRUNCATED AT 250 WORDS)

The buddy system: mediator--target locus of control and behavioral outcome.

The relative locus of control of mediator--target pairs was investigated within a contingency management program. As predicted, less improvement in target behaviors occurred for pairs in which the target scored lower in externality than the mediator. In addition, the greater externality of the mediator relative to the assigned target, the less improvement in target behavior (r=-.67). In contrast, improvement in target behavior bore no relationship with the locus of control scores of either mediators or targets correlated separately, nor with the differences between mediator--target locus of control scores within pairs in which the target scored equal to or higher in externality than the mediator.