[2] In a hemodynamically unstable patient with high-risk mechanism of injury, peritoneal lavage is a means of rapidly diagnosing intra-abdominal injury requiring laparotomy, but has largely been replaced in trauma care by the use of a focused assessment with sonography for trauma (FAST scan) due to its repeatability, non-invasiveness and non-interference with subsequent computed tomography (CT scan).
Abdominal CT and contrast duodenography may complement lavage in stable patients, but in an unstable or uncooperative persons, these studies are too time-consuming or require ill-advised sedation.
Magnetic resonance imaging is extremely accurate for the anatomic definition of structural injury, but logistics limit its practical application in acute abdominal trauma.
[5][6] After the application of local anesthesia, a vertical skin incision is made one third of the distance from the umbilicus to the pubic symphysis.
If no blood is aspirated, 1 litre of warm 0.9% saline is infused and after a few (usually 5) minutes this is drained and sent for analysis.