Additional means of draining pleural fluid are also available Thoracostomy using small “pigtail” tubes placed by Seldinger technique is minimally more invasive than needle thoracentesis and allows for ongoing drainage as needed Again, ultrasound guidance can be utilized at the bedside, or the location of maximal fluid can be marked prior to drainage Complex effusions may be less amenable to drainage by pigtail catheters and may require concomitant early use of fibrinolytics or a larger gauge tube Image-guided catheter drainage is most effective in patients with short duration of symptoms, free-flowing or unilocular effusions, absence of thick pleural peel, and fluid collections that can be easily reached Other approaches for more advanced disease include surgical tube thoracotomy; video-assisted thoracoscopic surgery (VATS), which allows directed chest tube placement and debridement; and mini thoracotomy with open pleural decortication Diagnostic tests of pleural fluid should include gross and microscopic examination, Gram stain, aerobic and anaerobic cultures, glucose, protein, albumin, LDH, cell count with differential, and pH determinations; cytology should be sent if malignancy is known or suspected For patients with exudative effusions, pleural fluid pH measurement is helpful in guiding decisions regarding drainage In adult patients, pH values of greater than 7.2 to 7.3 are generally found in sterile pleural fluid that does not require further drainage One exception is Proteus mirabilis infection, which causes an elevated pleural fluid pH In contrast, a pH of less than 7.0 is seen only in empyema, collagen vascular disease, or esophageal rupture With regard to management, a pleural fluid pH of less than 7.2 suggests that the effusion will likely require chest tube drainage A pleural fluid:serum glucose ratio less than 0.5 has a similar differential diagnosis as low pleural fluid pH In animal studies, both leukocytes and bacteria have been shown to use glucose anaerobically, resulting in reduced glucose concentration Diseases associated with low pleural fluid glucose (less than 60 mg/dL) include infectious causes including empyema, collagen vascular diseases, malignancies, and esophageal rupture Clinical Indications for Discharge or Admission Disposition for patients with pleurisy and effusion depends on the degree of pain and pulmonary compromise, as well as status of underlying condition and ability to treat as an outpatient If imaging is negative, patients with adequate pain control and no respiratory compromise can be safely treated as outpatients Most patients with nontrivial pleural effusions will require admission for ongoing