Carl R. O'Donnell

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.

Esophageal and transpulmonary pressures in acute respiratory failure

Objective:Pressure inflating the lung during mechanical ventilation is the difference between pressure applied at the airway opening (Pao) and pleural pressure (Ppl). Depending on the chest walls contribution to respiratory mechanics, a given positive end-expiratory and/or end-inspiratory plateau pressure may be appropriate for one patient but inadequate or potentially injurious for another. Thus, failure to account for chest wall mechanics may affect results in clinical trials of mechanical ventilation strategies in acute respiratory distress syndrome. By measuring esophageal pressure (Pes), we sought to characterize influence of the chest wall on Ppl and transpulmonary pressure (PL) in patients with acute respiratory failure. Design:Prospective observational study. Setting:Medical and surgical intensive care units at Beth Israel Deaconess Medical Center. Patients:Seventy patients with acute respiratory failure. Interventions:Placement of esophageal balloon-catheters. Measurements and Main Results:Airway, esophageal, and gastric pressures recorded at end-exhalation and end-inflation Pes averaged 17.5 ± 5.7 cm H2O at end-expiration and 21.2 ± 7.7 cm H2O at end-inflation and were not significantly correlated with body mass index or chest wall elastance. Estimated PL was 1.5 ± 6.3 cm H2O at end-expiration, 21.4 ± 9.3 cm H2O at end-inflation, and 18.4 ± 10.2 cm H2O (n = 40) during an end-inspiratory hold (plateau). Although PL at end-expiration was significantly correlated with positive end-expiratory pressure (p < .0001), only 24% of the variance in PL was explained by Pao (R2 = .243), and 52% was due to variation in Pes. Conclusions:In patients in acute respiratory failure, elevated esophageal pressures suggest that chest wall mechanical properties often contribute substantially and unpredictably to total respiratory impedance, and therefore Pao may not adequately predict PL or lung distention. Systematic use of esophageal manometry has the potential to improve ventilator management in acute respiratory failure by providing more direct assessment of lung distending pressure.

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.

Effect of a Brief Video Intervention on Incident Infection among Patients Attending Sexually Transmitted Disease Clinics

Background Sexually transmitted disease (STD) prevention remains a public health priority. Simple, practical interventions to reduce STD incidence that can be easily and inexpensively administered in high-volume clinical settings are needed. We evaluated whether a brief video, which contained STD prevention messages targeted to all patients in the waiting room, reduced acquisition of new infections after that clinic visit. Methods and Findings In a controlled trial among patients attending three publicly funded STD clinics (one in each of three US cities) from December 2003 to August 2005, all patients (n = 38,635) were systematically assigned to either a theory-based 23-min video depicting couples overcoming barriers to safer sexual behaviors, or the standard waiting room environment. Condition assignment alternated every 4 wk and was determined by which condition (intervention or control) was in place in the clinic waiting room during the patients first visit within the study period. An intent-to-treat analysis was used to compare STD incidence between intervention and control patients. The primary endpoint was time to diagnosis of incident laboratory-confirmed infections (gonorrhea, chlamydia, trichomoniasis, syphilis, and HIV), as identified through review of medical records and county STD surveillance registries. During 14.8 mo (average) of follow-up, 2,042 patients (5.3%) were diagnosed with incident STD (4.9%, intervention condition; 5.7%, control condition). In survival analysis, patients assigned to the intervention condition had significantly fewer STDs compared with the control condition (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.84 to 0.99). Conclusions Showing a brief video in STD clinic waiting rooms reduced new infections nearly 10% overall in three clinics. This simple, low-intensity intervention may be appropriate for adoption by clinics that serve similar patient populations. Trial registration: http://www.ClinicalTrials.gov (#NCT00137670).

Tracheal Collapsibility in Healthy Volunteers during Forced Expiration: Assessment with Multidetector CT

PURPOSE To assess forced expiratory tracheal collapsibility in healthy volunteers by using multidetector computed tomography and to compare the results with the current diagnostic criterion for tracheomalacia. MATERIALS AND METHODS An institutional review board approved this HIPAA-compliant study. After informed consent was obtained, 51 healthy volunteers (age range, 25-75 years) with normal spirometry results and no history of smoking or risk factors for tracheomalacia were prospectively studied. Volunteers were imaged with a 64-detector row scanner, with spirometric monitoring at total lung capacity and during forced exhalation, with 40 mAs, 120 kVp, and 0.625-mm detector collimation. Cross-sectional area and sagittal and coronal diameters of the trachea were measured 1 cm above the aortic arch and 1 cm above the carina. The percentage of expiratory collapse, the reduction in sagittal and coronal diameters, and the number of participants exceeding the current diagnostic criterion (>50% expiratory reduction in cross-sectional area) for tracheomalacia were calculated. RESULTS The final study population included 25 men and 26 women (mean age, 50 years). The mean percentage of expiratory reduction in tracheal lumen cross-sectional area was 54.34% +/- 18.6 (standard deviation) in the upper trachea and 56.14% +/- 19.3 in the lower trachea. Forty (78%) participants exceeded the current diagnostic criterion for tracheomalacia in the upper and/or lower trachea. Decreases in cross-sectional area of the upper and lower trachea correlated well with decreases in sagittal (r = 0.807 and 0.688, respectively) and coronal (r = 0.779 and 0.751, respectively) diameters (P < .001 for each correlation). CONCLUSION Healthy volunteers demonstrate a wide range of forced expiratory tracheal collapse, frequently exceeding the current diagnostic criterion for tracheomalacia.

Esophageal pressures in acute lung injury: do they represent artifact or useful information about transpulmonary pressure, chest wall mechanics, and lung stress?

Acute lung injury can be worsened by inappropriate mechanical ventilation, and numerous experimental studies suggest that ventilator-induced lung injury is increased by excessive lung inflation at end inspiration or inadequate lung inflation at end expiration. Lung inflation depends not only on airway pressures from the ventilator but, also, pleural pressure within the chest wall. Although esophageal pressure (Pes) measurements are often used to estimate pleural pressures in healthy subjects and patients, they are widely mistrusted and rarely used in critical illness. To assess the credibility of Pes as an estimate of pleural pressure in critically ill patients, we compared Pes measurements in 48 patients with acute lung injury with simultaneously measured gastric and bladder pressures (Pga and P(blad)). End-expiratory Pes, Pga, and P(blad) were high and varied widely among patients, averaging 18.6 +/- 4.7, 18.4 +/- 5.6, and 19.3 +/- 7.8 cmH(2)O, respectively (mean +/- SD). End-expiratory Pes was correlated with Pga (P = 0.0004) and P(blad) (P = 0.0104) and unrelated to chest wall compliance. Pes-Pga differences were consistent with expected gravitational pressure gradients and transdiaphragmatic pressures. Transpulmonary pressure (airway pressure - Pes) was -2.8 +/- 4.9 cmH(2)O at end exhalation and 8.3 +/- 6.2 cmH(2)O at end inflation, values consistent with effects of mediastinal weight, gravitational gradients in pleural pressure, and airway closure at end exhalation. Lung parenchymal stress measured directly as end-inspiratory transpulmonary pressure was much less than stress inferred from the plateau airway pressures and lung and chest wall compliances. We suggest that Pes can be used to estimate transpulmonary pressures that are consistent with known physiology and can provide meaningful information, otherwise unavailable, in critically ill patients.

Multidimensional Dyspnea Profile: an instrument for clinical and laboratory research

There is growing awareness that dyspnoea, like pain, is a multidimensional experience, but measurement instruments have not kept pace. The Multidimensional Dyspnea Profile (MDP) assesses overall breathing discomfort, sensory qualities, and emotional responses in laboratory and clinical settings. Here we provide the MDP, review published evidence regarding its measurement properties and discuss its use and interpretation. The MDP assesses dyspnoea during a specific time or a particular activity (focus period) and is designed to examine individual items that are theoretically aligned with separate mechanisms. In contrast, other multidimensional dyspnoea scales assess recalled recent dyspnoea over a period of days using aggregate scores. Previous psychophysical and psychometric studies using the MDP show that: 1) subjects exposed to different laboratory stimuli could discriminate between air hunger and work/effort sensation, and found air hunger more unpleasant; 2) the MDP immediate unpleasantness scale (A1) was convergent with common dyspnoea scales; 3) in emergency department patients, two domains were distinguished (immediate perception, emotional response); 4) test–retest reliability over hours was high; 5) the instrument responded to opioid treatment of experimental dyspnoea and to clinical improvement; 6) convergent validity with common instruments was good; and 7) items responded differently from one another as predicted for multiple dimensions. The Multidimensional Dyspnea Profile provides a unified, reliable instrument for both clinical and laboratory research http://ow.ly/Ix8ic

Comparison of Plethysmographic and Helium Dilution Lung Volumes: Which Is Best for COPD?

BACKGROUND Theoretical considerations and limited scientific evidence suggest that whole-body plethysmography overestimates lung volume in patients with severe airflow obstruction. We sought to compare plethysmography (Pleth)-, helium dilution (He)- and CT scan-derived lung volume measurements in a sample containing many patients with severe airflow obstruction. METHODS We measured total lung capacity (TLC) in 132 patients at three hospitals, with monitored application of recommended techniques for Pleth and He measurements of lung volume and by thoracic CT scans obtained during breath hold at full inspiration. RESULTS Average TLC among 132 subjects was 6.18 L (+/- 1.69 L) by Pleth-derived TLC, 5.55 L (+/- 1.39 L) by He-derived TLC, and 5.31 L (+/- 1.47) by CT scan-derived TLC. Pleth-derived TLC was significantly greater than either He-derived TLC or CT scan-derived TLC (P < or = .001), whereas there was no significant difference between He-derived and CT scan-derived values. When examined separately, there were significant within-subject differences in TLC by measurement technique among subjects with airflow obstruction, but not among those without airflow obstruction. Plethysmographic overestimation of TLC was greatest among subjects with FEV(1) < 30% of predicted. CONCLUSIONS In the setting of airflow obstruction, Pleth systematically overestimates lung volume relative to He or thoracic imaging despite adherence to current recommendations for proper measurement technique.

Quality Initiatives Respiratory Instructions for CT Examinations of the Lungs: A Hands-on Guide

In computed tomographic (CT) examinations of the lung, accurate visualization of the natural contrast between the low attenuation of air and the relatively higher attenuation of vessels, airways, and interstitial structures requires cooperative and coordinated respiratory maneuvers by the patient. Inadequate respiratory maneuvers can influence differences in lung attenuation and lead to misinterpretation by (a) increasing attenuation to simulate disease in normal patients, (b) decreasing attenuation to simulate normal contrast in patients with disease, or (c) creating motion artifacts. For respiratory maneuvers to be effective, patients have to be instructed before the examination and coached during it. However, comprehensive descriptions of such instructions and coaching are lacking in the radiology literature. Therefore, respiratory instructions specifically for use in thoracic CT examinations have been devised. Along with patient coaching, use of these instructions can improve image quality. With this hands-on guide, both radiologists and technologists can optimize the respiratory instructions given to their patients and thereby improve the quality of thoracic CT examinations.

Impact of lung volume on MR signal intensity changes of the lung parenchyma

To test the hypothesis that, in magnetic resonance (MR) imaging of healthy individuals, equal relative changes in lung volume cause equal relative changes in MR signal intensity of the lung parenchyma.