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Association of ozone exposure with asthma, allergic rhinitis, and allergic sensitization.

Children are vulnerable to air pollution, which is known to be related to the recent increasing trend of allergic disease.

OBJECTIVE: To investigate the effects of air pollution on respiratory allergic diseases in school children.

METHODS: A prospective survey of parental responses to International Study of Asthma and Allergies in Childhood questionnaires, together with allergy evaluation, was conducted in 1743 school children selected from metropolitan cities and industrial areas during a 2-year period. Individual exposure to air pollution was estimated by using a geometric information system with the 5-year mean concentration of air pollutants.

RESULTS: A total of 1,340 children (male:female ratio, 51.4:48.6) with a mean (SD) age of 6.84 (0.51) years were included in the analysis. Each child underwent allergy evaluation at the time of enrollment and at a 2-year follow-up. After 2 years, the 12-month prevalence of wheezing was significantly decreased, whereas the lifetime prevalence of allergic rhinitis showed a significant increase. Ozone exposure was significantly associated with the 12-month prevalence of wheeze (odds ratio per 5 ppb, 1.372; 95% confidence interval, 1.016-1.852). Ozone was also associated with allergic rhinitis in children who reside in industrial areas. In addition, significant positive associations between ozone and the rate of newly developed sensitization to outdoor allergen were found (P for trend = .007).

CONCLUSION: Exposure to ozone was associated with current wheeze and allergic rhinitis. An increased rate of newly developed sensitization to outdoor allergen by ozone may explain the association.

Clinical detection and monitoring of acute pulmonary embolism: proof of concept of a computer-based method.

The diagnostic ability of computer-based methods for cardiovascular system (CVS) monitoring offers significant clinical potential. This research tests the clinical applicability of a newly improved computer-based method for the proof of concept case of tracking changes in important hemodynamic indices due to the influence acute pulmonary embolism (APE).

METHODS: Hemodynamic measurements from a porcine model of APE were used to validate the method. Of these measurements, only those that are clinically available or inferable were used in to identify pig-specific computer models of the CVS, including the aortic and pulmonary artery pressure, stroke volume, heart rate, global end diastolic volume, and mitral and tricuspid valve closure times. Changes in the computer-derived parameters were analyzed and compared with experimental metrics and clinical indices to assess the clinical applicability of the technique and its ability to track the disease state.

RESULTS: The subject-specific computer models accurately captured the increase in pulmonary resistance (Rpul), the main cardiovascular consequence of APE, in all five pigs trials, which related well (R2 = 0.81) with the experimentally derived pulmonary vascular resistance. An increase in right ventricular contractility was identified, as expected, consistent with known reflex responses to APE. Furthermore, the modeled right ventricular expansion index (the ratio of right to left ventricular end diastolic volumes) closely followed the trends seen in the measured data (R2 = 0.92) used for validation, with sharp increases seen in the metric for the two pigs in a near-death state. These results show that the pig-specific models are capable of tracking disease-dependent changes in pulmonary resistance (afterload), right ventricular contractility (inotropy), and ventricular loading (preload) during induced APE. Continuous, accurate estimation of these fundamental metrics of cardiovascular status can help to assist clinicians with diagnosis, monitoring, and therapy-based decisions in an intensive care environment. Furthermore, because the method only uses measurements already available in the ICU, it can be implemented with no added risk to the patient and little extra cost.

CONCLUSIONS: This computer-based monitoring method shows potential for real-time, continuous diagnosis and monitoring of acute CVS dysfunction in critically ill patients.

Does the Pulmonary Embolism Severity Index accurately identify low risk patients eligible for outpatient treatment?

The pulmonary embolism severity index (PESI) and the recently derived simplified PESI prognostic model have been developed to estimate the risk of 30-day mortality in patients with acute PE. We sought to assess if the PESI and simplified PESI prognostic models can accurately identify adverse events and to determine the rates of events in patients treated as outpatients.

METHODS: A retrospective cohort study of patients with acute pulmonary embolism (PE) presenting at the Ottawa Hospital (Canada) was conducted between 1 January 2007 and 31 December 2008.

RESULTS: Two hundred and forty three patients were included. A total of 118 (48.6%) and 81 (33.3%) were classified as low risk patients using the original and simplified PESI prognostic models respectively. None of the low risk patients died within the 3months of follow-up. One hundred and fifteen (47.3%) patients were safely treated as outpatients with no deaths or bleeding episodes and only 1 recurrent event within the first 14days or after 30days of follow-up. Thirty four (29.6%) of these outpatients were classified as high risk patients according to the original PESI and 54 (47.0%) to the simplified PESI prognostic model.

CONCLUSION: Both PESI strategies accurately identify patients with acute PE who are at low risk and high risk for short-term adverse events. However, 30 to 47% of patients with acute PE and a high risk PESI score were safely managed as outpatients. Future research should be directed at developing tools that predict which patients would benefit from inpatient management.

Effects of age on the risk of dying from pulmonary embolism or bleeding during treatment of deep vein thrombosis.

The risk of patients dying of pulmonary embolism (PE) or bleeding during the treatment of deep vein thrombosis (DVT), and whether these risks are influenced by patient age, has not been thoroughly studied.

METHODS: We used data from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) to assess the risk of fatal PE and fatal bleeding in 16,199 patients with lower limb DVT (without symptomatic PE at the time of inclusion) during the 3 months after diagnosis, with patients categorized according to age.

RESULTS: During the 3 months of anticoagulant treatment, there were 31 fatal PEs (0.19%) and 83 fatal hemorrhages (0.51%). During the first 7 days of therapy, the frequency of fatal PEs was similar to that of fatal bleeding (12 vs 14 deaths, respectively; odds ratio [OR], 0.86; 95% confidence interval [CI], 0.39-1.87). However, from days 8 to 90, the frequency of fatal bleeding was greater than that of fatal PE (69 vs 19 deaths; OR, 3.64; 95% CI, 2.22-6.20). The higher frequency of fatal bleeding compared with fatal PE from days 8 to 90 appeared to be confined to patients who were aged ≥60 years. Multivariate analysis showed that patient age was independently associated with an increased risk of death from bleeding during the first 3 months: every 10 years the OR increased by 1.37 (95% CI, 1.12-1.67).

CONCLUSIONS: During the first week of treatment, the risk of fatal bleeding and fatal PE were similar. Then, particularly in patients who were aged ≥60 years, the risk of dying from bleeding exceeded the risk of dying from PE.

68Ga PET/CT Ventilation-Perfusion Imaging for Pulmonary Embolism: A Pilot Study with Comparison to Conventional Scintigraphy.

Ventilation-perfusion (V/Q) scintigraphy is established for regional assessment of lung function in a variety of diseases, including pulmonary embolism (PE). PET/CT may further improve the accuracy and utility of V/Q imaging because of its superior technical characteristics.

This pilot study assessed the feasibility of performing V/Q PET/CT and compared diagnostic utility with conventional V/Q imaging in patients with clinical suspicion of PE.

METHODS: Ten patients undergoing conventional V/Q imaging were prospectively recruited. PET/CT V/Q imaging was performed after inhalation of (68)Ga-carbon nanoparticles ("Galligas") and administration of (68)Ga-macroaggregated albumin. Blinded to the results of the other study, SPECT/CT (n = 9) or SPECT (n = 1) images and PET/CT images were graded by a predefined scoring system for scan quality. The number of matched or unmatched defects and diagnosis were also measured and compared with a final diagnosis.

RESULTS: PET image quality was equivalent or superior to SPECT in all patients, with more homogeneous radiotracer distribution for both ventilation and perfusion studies (P < 0.01). Based on conventional V/Q imaging, the diagnosis was acute PE in 2 patients and no PE in 7 patients, and the imaging results were nondiagnostic in 1 patient. The PET/CT diagnosis was concordant in 8 patients, and these studies demonstrated a similar number and distribution of matched and unmatched defects. In 1 discordant case, a patient with a SPECT/CT study that was nondiagnostic because of severe airway disease showed no PE on PET/CT. In another, the diagnosis of PE established on SPECT/CT was not reported on PET/CT 2 d later, possibly because of interval clot lysis or migration.

CONCLUSION: This intraindividual comparative study demonstrated that V/Q PET/CT with (68)Ga-labeled radiotracers can be performed in clinical practice. Compared with conventional V/Q imaging, advantages include higher-resolution, fully tomographic images with potentially better regional quantitation of lung function. The short half-life of (68)Ga also enables more flexible acquisition protocols with the option of performing ventilation studies selectively on patients with abnormal perfusion. On the basis of our results, further studies are indicated to assess whether V/Q PET/CT can improve diagnostic algorithms for patients with suspected PE.

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