At one time, diagnostic peritoneal lavage (DPL), described by Root in 1965,  was the diagnostic test of choice to detect bleeding within the abdominal cavity after trauma. However, the advent and widespread availability of computed tomography (CT), which carries near-comparable sensitivity and superior specificity,  have limited the use of DPL to the diagnosis of intra-abdominal hemorrhage in unstable trauma patients.
Currently, DPL is performed infrequently, having been largely replaced by focused assessment with sonography for trauma (FAST) and CT. The American College of Surgeons adopted FAST into the Advanced Trauma Life Support (ATLS) protocol, and the ninth edition of ATLS made DPL an optional skill station, owing to the widespread use of FAST. Still, each of these diagnostic modalities has unique advantages and disadvantages. DPL retains its usefulness, especially in the hemodynamically unstable trauma patient who has a negative or equivocal FAST examination.
A positive FAST examination (hemoperitoneum) is useful and reliable in the hemodynamically unstable blunt trauma patient. However, if the FAST examination is negative or equivocal, it should be followed by a DPL. DPL is 100% accurate for intra-abdominal injury in hemodynamically unstable patients, whereas FAST is positive only 45% of the time.  However, DPL also takes 10-15 minutes, and the patient must be stable for the test to be carried out.
In the hemodynamically stable patient, CT is preferred because it is noninvasive and highly accurate. If CT is unavailable, either FAST or DPL may be used. DPL should also be considered in patients who have an unreliable examination or those at high risk for hollow-viscus injury (HVI), particularly when CT or ultrasonography detects minimal fluid or when the patient manifests fever, peritonitis, or both. This circumstance usually occurs 6-12 hours after an HVI.
DPL, though lacking organ specificity, remains the most sensitive test for mesenteric injury and HVI. FAST is rapid, noninvasive, and can be repeated multiple times; however, it is more user-dependent than DPL or CT. Both FAST and DPL fail to evaluate retroperitoneal and diaphragmatic injuries and poorly identify solid-organ injuries. Abdominopelvic CT requires a hemodynamically stable patient, is costly, and carries a small but significant lifetime risk of malignancy. However, CT reliably diagnoses solid-organ injuries and evaluates the retroperitoneum, but it is less sensitive and specific for HVIs and mesenteric injuries than DPL is. 
As a result of these differences (see Table 1 below), all three tests continue to play important roles in the evaluation of a trauma patient for abdominal injuries. 
Table 1. Comparison Parameters for DPL, FAST, and CT (Open Table in a new window)
|Time||10-15 min||2-4 min||Variable|
|Repeatability||Possible, but rarely done||Easy and frequently done||Yes|
|Reliability||Not organ specific||Operator dependent||Obesity, movement|
|Advantages||Inexpensive, mobile, detects bowel injury||Noninvasive, rapid, mobile, moderately expensive (equipment)||Noninvasive, highly accurate, fixed, expensive (equipment)|
|Disadvantages||Invasive, misses retroperitoneal and diaphragm injuries||Hampered by subcutaneous or intra-abdominal air, obesity, pelvic fractures||Misses diaphragm, small bowel, and pancreatic injuries; radiation|
DPL can be used to evaluate both blunt and penetrating abdominal trauma in patients who are hemodynamically unstable or who require urgent surgical intervention for associated extra-abdominal injuries. DPL can rapidly confirm or exclude the presence of intraperitoneal hemorrhage. Thus, the patient with a closed head injury, the unstable patient who has been in a motor vehicle accident, or the patient with a pelvic fracture and potential retroperitoneal hemorrhage can be appropriately triaged to emergency laparotomy.
A negative result on peritoneal aspiration allows the clinician to proceed to alternative management steps and allows the patient to forgo unnecessary laparotomy. Additionally, DPL can be used in nonemergency circumstances as a means of detecting solid-organ injury or HVI requiring laparotomy. [6, 7]
In the evaluation of patients with blunt abdominal trauma or penetrating anterior abdominal stab wounds, DPL provides the following benefits:
Rapid determination of the presence or absence of hemoperitoneum
Detection of intraperitoneal injury requiring laparotomy in stable patients
Rapid triage when the source of hemodynamic instability is unknown
An obvious need for laparotomy is the only absolute contraindication for DPL. Lack of training or familiarity with performing DPL, prior abdominal surgery, abdominal wall infections, coagulopathy, morbid obesity, and second- or third-trimester pregnancy are all relative contraindications. 
A diagnostic peritoneal lavage kit, either commercially available or preassembled in the hospital, contains the following (see the image below):
Scalpel (No. 11 and No. 15 blades)
Alice forceps (2)
Toothed dissecting forceps
Syringes (2), 5 mL
Syringe, 10 mL
Needles, 18 and 21 gauge
Lidocaine 1% with epinephrine
Warm lactated Ringer solution or normal saline solution (0.9% NaCl), 1 L
Intravenous (IV) bottle or bag connected to an IV set
Absorbable sutures, 4-0
Typically, local anesthesia is obtained by infiltrating lidocaine 1% with epinephrine. (For more information, see Local Anesthetic Agents, Infiltrative Administration.) The patient should be kept in a supine position.
Traditionally, diagnostic peritoneal lavage (DPL) is performed in two steps. First, the clinician attempts to aspirate free intraperitoneal blood. If 10 mL or more of blood is aspirated, the procedure stops because intraperitoneal injury is likely. Second, if little or no blood is detected, the clinician performs a lavage of the peritoneal cavity with either normal saline or lactated Ringer solution, and the effluent is sent for laboratory evaluation. Routine bile staining, Gram staining, and microscopy to identify vegetable fibers are rarely productive and are of untested accuracy.
Aspiration and lavage
Decompression of the stomach and bladder is recommended with a nasogastric tube and a Foley catheter, respectively, to prevent inadvertent gastric or bladder injury.
Prepare the site of placement with standard skin antiseptics (eg, povidone-iodine or chlorhexidine), and drape the patient appropriately. Be sure to observe sterile precautions throughout the procedure.
Liberally infiltrate the local anesthetic (lidocaine 1% with epinephrine) into the area for incision and passage of the needle and catheter. (See the video below.)
Using the Seldinger technique, insert a small-gauge guide needle into the peritoneal cavity in the infraumbilical midline. Pass a J-wire through the needle, and direct it caudad and toward the right or left pelvic gutter. Then withdraw the needle over the wire, leaving the wire in place and allowing for the placement of a soft catheter into the peritoneal cavity.
Stab the entry site of the wire with a No. 11 scalpel; this facilitates passage of the catheter through the abdominal wall. Gentle twisting or rotation of the catheter and passing it over the guide wire while aiming toward the right or left pelvic gutter is recommended to facilitate passage into the peritoneal cavity. (See the videos below.)
Withdraw the wire, leaving the catheter in place. Perform aspiration, followed by lavage, if necessary. Recovery of 10 mL of blood is considered a positive finding, and the procedure is terminated. In penetrating trauma, the acquisition of lesser amounts may be meaningful because of the tendency for the diaphragm and bowel to hemorrhage minimally when injured.
For lavage, attach intravenous (IV) extension tubing to the catheter, then instill 1 L of warmed normal saline or lactated Ringer solution in adults (or 15 mL/kg in children). When possible, roll or shift the patient from side to side after infusion to increase mixing.
Next, place the IV bag on the floor (or below abdominal level), and allow the fluid to return through the effect of gravity. It is generally accepted that the return of 700 mL or more in adults is adequate for interpretation. However, as little as 10-20% of the infusate may be sufficient for both gross and microscopic determinations. Only 10 mL of fluid need be sent to the laboratory for cell count analysis, and another 10 mL can be sent for enzyme analysis. (See the image below.)
The infused fluid may not return or may stop after a short while, because of several factors. Some IV tubing contains a one-way valve or inadequate suction. This problem can be corrected by insertion of a needle into the second opening at the bottom of the IV bag for aspiration of 10 mL of air. Alternatively, the catheter may be adherent to the peritoneum. If so, gently twisting or rotating the catheter and applying abdominal pressure may aid flow return.
Once enough fluid is returned, remove the catheter, and close the skin with an absorbable subcuticular suture, cuticular nylon, or staple(s). (See the image below.)
Analysis of fluid
Diagnostic criteria are outlined in Tables 2 and 3 below.
|Amylase level (IU/L)||≥20||10-19|
|Alkaline phosphatase level (IU/L)||≥3||NA*|
|White blood cells (per μL)||>500||250-500|
|*NA = Not applicable.|
Potential complications of DPL include the following:
False-positive results - These may result from (1) insertion through iatrogenic misadventure, (2) placement of the catheter through an abdominal wall hematoma, (3) inadequate hemostasis, or (4) bleeding from the penetrating abdominal wall injury
Unnecessary laparotomy - This may occur if hemoperitoneum is detected in a hemodynamically stable patient
Potential failure to recover lavage fluid - This may be the result of (1) inadvertent placement of the catheter into the preperitoneal space, (2) compartmentalization of fluid by adhesions, (3) obstruction of fluid outflow (eg, by omentum), or (4) fluid pooling in the intrathoracic cavity due to diaphragmatic injury