Pleural Effusion: Diagnostic Approach in Adults.

Pleural effusion affects 1.5 million patients in the United States each year. New effusions require expedited investigation because treatments range from common medical therapies to invasive surgical procedures. The leading causes of pleural effusion in adults are heart failure, infection, malignancy, and pulmonary embolism. The patient's history and physical examination should guide evaluation. Small bilateral effusions in patients with decompensated heart failure, cirrhosis, or kidney failure are likely transudative and do not require diagnostic thoracentesis. In contrast, pleural effusion in the setting of pneumonia (parapneumonic effusion) may require additional testing. Multiple guidelines recommend early use of point-of-care ultrasound in addition to chest radiography to evaluate the pleural space. Chest radiography is helpful in determining laterality and detecting moderate to large pleural effusions, whereas ultrasonography can detect small effusions and features that could indicate complicated effusion (i.e., infection of the pleural space) and malignancy. Point-of-care ultrasound should also guide thoracentesis because it reduces complications. Computed tomography of the chest can exclude other causes of dyspnea and suggest complicated parapneumonic or malignant effusion. When diagnostic thoracentesis is indicated, Light's criteria can help differentiate exudates from transudates. Pleural aspirate should routinely be evaluated using Gram stain, cell count with differential, culture, cytology, protein, l-lactate dehydrogenase, and pH levels. Additional assessments should be individualized, such as tuberculosis testing in high-prevalence regions. Parapneumonic effusions are the most common cause of exudates. A pH level less than 7.2 is indicative of complicated parapneumonic effusion and warrants prompt consultation for catheter or chest tube drainage, possible tissue plasminogen activator/deoxyribonuclease therapy, or thoracoscopy. Malignant effusions are another common cause of exudative effusions, with recurrent effusions having a poor prognosis.

Modulation of visually guided action by the image and familiar sizes of real-world objects.

In daily life, two aspects of real-world object size perception-the image size of an object and its familiar size in the real world-are highly correlated. Thus, whether these two aspects of object size differently affect goal-directed action (e.g., manual pointing) and how have scarcely been examined. Here, participants reached to touch one of two simultaneously presented objects based on either their image or familiar size, which could be congruent or incongruent (e.g., a rubber duck presented as smaller and larger than a boat, respectively). We observed that when pointing to target objects in the incongruent conditions, participants' movements were slower and were more curved toward the incorrect object compared with the movements in the congruent conditions. By comparing performance in the congruent and incongruent conditions, we concluded that both image size and familiar size influenced action even when task irrelevant, indicating that both are processed automatically (Konkle & Oliva, 2012a). Image size, however, showed influence earlier in the course of movements and more robustly overall than familiar size. We additionally found that greater relative familiar size differences mitigated the impact of image size processing and increased the impact of familiar size processing on pointing movements. Overall, our data suggest that image size and familiar size perception interact both with each other and with visually guided action, but that the relative contributions of each are unequal and vary based on task demands.

Dynamic modulation of illusory and physical target size on separate and coordinated eye and hand movements.

In everyday behavior, two of the most common visually guided actions-eye and hand movements-can be performed independently, but are often synergistically coupled. In this study, we examine whether the same visual representation is used for different stages of saccades and pointing, namely movement preparation and execution, and whether this usage is consistent between independent and naturalistic coordinated eye and hand movements. To address these questions, we used the Ponzo illusion to dissociate the perceived and physical sizes of visual targets and measured the effects on movement preparation and execution for independent and coordinated saccades and pointing. During independent movements, we demonstrated that both physically and perceptually larger targets produced faster preparation for both effectors. Furthermore, participants who showed a greater influence of the illusion on saccade preparation also showed a greater influence on pointing preparation, suggesting that a shared mechanism involved in preparation across effectors is influenced by illusions. However, only physical but not perceptual target sizes influenced saccade and pointing execution. When pointing was coordinated with saccades, we observed different dynamics: pointing no longer showed modulation from illusory size, while saccades showed illusion modulation for both preparation and execution. Interestingly, in independent and coordinated movements, the illusion modulated saccade preparation more than pointing preparation, with this effect more pronounced during coordination. These results suggest a shared mechanism, dominated by the eyes, may underlie visually guided action preparation across effectors. Furthermore, the influence of illusions on action may operate within such a mechanism, leading to dynamic interactions between action modalities based on task demands.