SAAG, Light criteria, and safe taps

SAAG. The serum-ascites albumin gradient correctly identified ascites due to portal hypertension 96.7 per cent of the time, against 55.6 per cent for the exudate-transudate concept.^[1] A high gradient is conventionally 1.1 g/dL or more.^[8]

Light's criteria. An exudate is suggested by a pleural fluid to serum protein ratio above 0.5, a pleural fluid to serum LDH ratio above 0.6, or pleural fluid LDH above two-thirds of the upper limit of normal for serum LDH; an exudate is less likely when all are absent.^[7]

Thoracentesis landmark. The intercostal artery runs in the neurovascular bundle along the subcostal groove below the inferior border of the rib, so insertion along the superior border of the rib is frequently performed; ultrasound can localise intercostal vessels.^[10] Ultrasonography was associated with a lower pneumothorax risk in a meta-analysis of 6605 thoracenteses.^[12]

The plasma request. In suspected spontaneous bacterial peritonitis, routine transfusion for coagulation abnormalities is not recommended, and commonly used INR thresholds are not supported by evidence.^[11][9]

Volume. In 185 large-volume thoracenteses, clinical re-expansion pulmonary oedema occurred in 0.5 per cent and was independent of the volume removed.^[4]