23 Jul - Pleural Effusion

This AMs case was a patient who presented with dyspnea and R chest pain 6 weeks following an episode of pneumonia.  CXR revealed a large R sided pleural effusion.

Thoracentesis was performed with findings of cloudy fluid with a protein ratio <0.5 but an LDH ration >0.6, consistent with an exudate.  No organisms were seen on gram stain and the glucose and cell counts were unremarkable.

Since we are not doing thoracentesis yet in the sim lab - you all should at least review the video here at the NEJM website before peforming this procedure.  Common ommisions that I have witnessed include not having the patient fully exhale and hold their breath when removing the catheter from the chest at the completion of the procedure.

To interpred the results of the pleural fluid analysis, consult these articles here and here by the guru of pleural fluid analysis Dr Light.  His criteria show up frequently on exams and challenge bowls:

pleural fluid / serum protein ratio >0.5
pleural fluid / serum LDH ratio >0.6
pleural fluid LDH > 2/3 the upper limit of serum normal value

Any one is sufficient to diagnose an exudative effusion, but the specificity is only 82 - 83%

Light's criteria are the most sensitive (98%), but a serum albumin - pleural albumin of <= 1.2 or a pleural fluid cholesterol >= 60 are both more specific at 92%