What's black and white and red (read) all over? The bedside interpretation of diagnostic peritoneal lavage fluid

Diagnostic peritoneal lavage (DPL) is often used to determine whether a blunt trauma victim has significant intra-abdominal hemorrhage. One bedside test (BT) historically recommended to evaluate DPL fluid is the ability to read newsprint through the fluid contained within intravenous (i.v.) tubing. Few experimental data support this practice. Two hundred eighteen traumatologists were queried regarding their use of BTs. In a related clinical study, blinded volunteers were asked to read print through various unmarked containers filled with simulated DPL fluid, created by adding aliquots of whole human blood to liter bags of lactated Ringer's solution. Of the 97 traumatologists who completed our preliminary survey, 60 per cent reported using a visual BT to assess DPL fluid. Of these surgeons, 44 per cent attempted to read newsprint through i.v. tubing. Our clinical study showed that more volunteers could read print through a red top tube (95%) when it contained a red cell concentration of 827 +/- 41/mm3 than the i.v. bag (4%). Nearly 70 per cent of volunteers were able to read print through the tubing containing 41,429 +/- 2,967 red blood cells (RBCs)/mm3. Regardless of the receptacle, readability was lost at RBC counts far below 100,000/mm3. Many traumatologists utilize BTs as an adjunct to clinical decision making. We conclude that, if the clinician can read print through lavage fluid within an i.v. bag, Vacutainer tube, or i.v. tubing, the DPL will be negative at cell count. However, inability to read print through i.v. tubing requires laboratory confirmation to document an RBC count > 100,000/mm3.