IntroductionThe purpose of this study was to evaluate if ultrasound derived measures of diaphragm thickening, rather than diaphragm motion, can be used to predict extubation success or failure. Methods Sixty-three mechanically ventilated patients were prospectively recruited. Diaphragm thickness (tdi) was measured in the zone of apposition of the diaphragm to the rib cage using a 7-10 MHz ultrasound transducer. The percent change in tdi between end-expiration and end-inspiration (Δtdi%) was calculated during either spontaneous breathing (SB) or pressure support (PS) weaning trials. A successful extubation was defined as SB for >48 h following endotracheal tube removal. Results Of the 63 subjects studied, 27 patients were weaned with SB and 36 were weaned with PS. The combined sensitivity and specificity of Δtdi%≥30% for extubation success was 88% and 71%, respectively. The positive predictive value and negative predictive value were 91% and 63%, respectively. The area under the receiver operating characteristic curve was 0.79 for Δtdi%. Conclusions Ultrasound measures of diaphragm thickening in the zone of apposition may be useful to predict extubation success or failure during SB or PS trials.

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The acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) was described 30 yr ago, yet making a definitive diagnosis remains difficult. The identification of biomarkers obtained from peripheral blood could provide additional noninvasive means for diagnosis. To identify gene expression profiles that may be used to classify patients with ALI, 13 patients with ALI + sepsis and 20 patients with sepsis alone were recruited from the Medical Intensive Care Unit of the University of Pittsburgh Medical Center, and microarrays were performed on peripheral blood samples. Several classification algorithms were used to develop a gene signature for ALI from gene expression profiles. This signature was validated in an independently obtained set of patients with ALI + sepsis (n = 8) and sepsis alone (n = 1). An eight-gene expression profile was found to be associated with ALI. Internal validation found that the gene signature was able to distinguish patients with ALI + sepsis from patients with sepsis alone with 100% accuracy, corresponding to a sensitivity of 100%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 100%. In the independently obtained external validation set, the gene signature was able to distinguish patients with ALI + sepsis from patients with sepsis alone with 88.9% accuracy. The use of classification models to develop a gene signature from gene expression profiles provides a novel and accurate approach for classifying patients with ALI.

It has become accepted that nitric oxide serves important functions in biological systems as a second messenger. Another diatomic gaseous molecule, carbon monoxide (CO), is also rapidly gaining acceptance as a signaling agent. Some of the activities of CO are analogous to those of nitric oxide in the vascular system and the brain, but CO also behaves in novel ways. Like nitric oxide, CO is capable of activating soluble guanylyl cyclase. This mechanism of CO signaling is important in vasodilation and neurotransmission. There is growing evidence, however, that CO also acts independently of soluble guanylyl cyclase. CO has been shown to protect against septic shock and lung injury in animal models, and the mitogen-activated protein kinase system appears to mediate this cytoprotective effect. Although much remains to be elucidated about the mechanisms of cell signaling by CO, the pace of discovery in this field is making the picture clearer with every passing day.

CD28 down-regulation on CD4 cells is associated with bronchiolitis obliterans syndrome and poor outcomes in lung transplantation recipients. CD4(+)CD28(null) cells have unusual, potentially pathogenic characteristics, and could be important in the progression of allograft dysfunction. These findings may illuminate a novel paradigm of transplantation immunopathogenesis, and suggest that CD28 measurements could identify recipients at risk for clinical deteriorations.

Management of airway inflammation requires proper monitoring and treatment to improve long-term outcomes. However, achieving this goal is difficult, as current methods have limitations. Although nitric oxide (NO) was first identified 200 years ago, its physiological importance was not recognized until the early 1980s. Many studies have established the role of NO as an essential messenger molecule in body systems. In addition, studies have demonstrated a significant relationship between changes in exhaled NO levels and other markers of airway inflammation. The technique used to measure NO in exhaled breath is noninvasive, reproducible, sensitive, and easy to perform. Consequently, there is growing interest in the use of exhaled NO in the management of asthma and other pulmonary conditions. The purpose of this review is to promote a basic understanding of the physiologic actions of NO, measurement techniques, and ways that research findings might translate to future application in clinical practice. Specifically, the article will review the role of exhaled NO in regard to its historical background, mechanisms of action, measurement techniques, and implications for clinical practice and research.

Thoracic actinomycosis is best treated with individualized therapeutic modalities, depending on factors such as the initial burden of disease, the performance of resectional surgery, and the clinical and radiologic responses to therapy. The traditional recommendation of IV antibiotic therapy for 2 to 6 weeks followed by oral antibiotic therapy for 6 to 12 months is not always necessary for all thoracic actinomycosis patients.

Background: Nitric oxide (NO) and carbon monoxide (CO) in exhaled breath are considered obtainable biomarkers of physiologic mechanisms. Therefore, obtaining their measures simply, noninvasively, and repeatedly, is of interest, and was the purpose of the current study.