EM Diagnostics: Pleural Fluid and Ascitic Fluid Analysis
/You settle down to your workstation in the ED on a crisp, 5 degree F January morning. There are 2 patients to be seen, just now having been brought in by a very chilly looking EMS crew.
The 1st patient is a 57 yo M coming in with a chief complaint of abdominal pain and swelling. A quick review of his chart shows he has a history of cirrhosis from HCV and gets frequent large volume paracentesis for symptomatic control. His last paracentesis was 1 week ago. Following this he noted he initially felt better but 2-3 days later started having increasing abdominal pain, vomiting, accompanied by subjective fever and chills. On exam you note that he has significant, diffuse abdominal tenderness; vitals P - 101, BP - 102/55, RR - 22, T - 99.9. You decide you are concerned for bacterial peritonitis and perform a diagnostic paracentesis early in his evaluation. As you wait for your labs to come back you try to plumb the depths of your memory to remember with certainty how to interpret the labs you just sent...
The 2nd patient is a 65 yo F coming in with shortness of breath. She has no known medical problems so as part of your workup you order a chest x-ray. The chest x-ray shows a large right-sided pleural effusion. She is significantly tachypneic and is requiring 4 L of oxygen to maintain an O2 sat of 92%. You decide to perform a thoracentesis to alleviate her symptoms and to help determine the cause of the large effusion. As you think through how to interpret the labs sent from the fluid analysis, you remember something about Light's Criteria but can't remember the specifics...
Videos and charts by Michael Klaszky, MD
Text and Intro by Jeffery Hill, MD MEd
