When assessing children who have sustained abdominal trauma, the emergency physician or surgeon must quickly determine if these children have sustained a serious injury necessitating emergency surgery. In some cases, this determination can be made on clinical grounds alone, but often a diagnostic procedure is required. Diagnostic peritoneal lavage (DPL) is one method by which abdominal injuries can be identified. Shortly after being introduced by Dr. Root in 1964, DPL became the primary means of evaluating the abdomen after blunt trauma (1). Peritoneal lavage is also used as a therapeutic tool in hypothermia (2). DPL involves two separate components, peritoneal aspiration and peritoneal lavage, if the aspiration is not successful in obtaining free peritoneal blood. DPL is a very sensitive modality for the detection of intraperitoneal blood but does not identify the injured organ or the need for exploratory laparotomy. In this era of new imaging modalities, noninvasive testing, and conservative management of the trauma victim, DPL is rarely performed (3,4,5). Today, DPL’s main utility lies in the evaluation of the hemodynamically unstable patient when bedside ultrasound is not available or provides equivocal results. For this reason, recommended techniques and applications of DPL are presented with particular emphasis on those aspects that specifically relate to children.

Because DPL is in many ways a “blind” procedure, it is important to understand the anatomy of the abdomen and especially how the abdominal anatomy of infants and young children differs from that of adults. The abdominal cavity is continuous with the pelvic cavity. It is bordered superiorly by the muscular thoracoabdominal diaphragm and inferiorly by the pelvic diaphragm. The anterior abdominal wall consists of skin, fat, and several layers of underlying muscles whose tendinous sheaths fuse together in the midline to form the linea alba. This relatively avascular area is the site for needle insertion into the abdominal cavity. In infants and young children, the muscles of the anterior abdominal wall are relatively weak when compared to those of adolescents and adults, providing less protection for the abdominal organs. The pliable bones of the child’s chest wall gives relative protection from rib fractures while allowing greater forces to be transmitted within the thoracic cavity, making these patients more susceptible to pulmonary contusions and injury to the intrathoracic abdominal organs—the diaphragm, liver, spleen, and stomach.

The intra-abdominal organs in children occupy a relatively larger portion of the abdominal cavity than these organs do in adults. The bladder is of particular concern, because in young children the bladder is more an abdominal than a pelvic organ. The stomach, when distended, may extend far into the abdominal cavity. Because young, crying children may ingest large quantities of air, a large, distended stomach should be anticipated. The combination of a relatively large liver and spleen and weak anterior abdominal muscles predisposes the child to splenic and/or hepatic hemorrhage after significant blunt abdominal trauma (5). Additionally, under certain circumstances, such as when a young child is involved in a motor vehicle accident while wearing a standard automobile lap belt, a hollow viscus injury can occur (6,7). Other important mechanisms for blunt abdominal injury in children include automobile verses pedestrian accidents and child abuse (8,9,10).

Clearly, all children who sustain an injury involving the abdomen are not candidates for DPL. On one end of the spectrum are the children who are determined to require urgent
laparotomy on clinical grounds alone. This group includes those who have (a) sustained gunshot wounds that clearly penetrate the peritoneum, (b) abdominal distension (which is persistent after gastric tube placement), (c) peritonitis, (d) hypotension (which does not respond to fluid resuscitation), (e) free peritoneal air, or (f) bleeding into the gastrointestinal tract. On the other end of the spectrum are those children in whom a significant injury can be reasonably excluded without further testing. This procedure should instead be reserved for patients who do not have a clear indication for laparotomy when close observation, serial examinations, and computed tomography (CT) are not an option. In trauma patients who require immediate nonabdominal surgery (e.g., craniotomy for the evacuation of an epidural hematoma), DPL may be performed in the operating room.

When DPL was introduced, management of suspected intra-abdominal injury was by emergency laparotomy. Although DPL certainly reduced the number of exploratory laparotomies for abdominal trauma, patients who had a positive DPL were still managed surgically. Since that time, however, two important changes have occurred that have had a profound effect on the evaluation and management of the potentially injured abdomen. First, advances in imaging technology have provided sophisticated and accurate forms of noninvasive imaging. Second, the overall trend in management of children with solid organ injury has changed from surgical management to nonsurgical management (11,12,13).

Ultrasonography (US) performed by a surgeon or emergency physician has largely replaced DPL in many trauma centers. In addition to detecting peritoneal fluid, US can identify pericardial fluid and hemothorax (14). It also has the advantages of being noninvasive, requiring no sedation and, because it is a bedside procedure, no patient transportation. It is extremely sensitive in identifying abnormal intraperitoneal fluid collections but less accurate in identifying the specific organ injured (15,16,17). This technique has not proved to be as useful as CT scanning in detecting the exact location and extent of injury, but in several studies it has been shown to compare favorably to DPL in detecting the presence of injury (15,18,19) (see also Chapter 137).

CT has become the imaging modality of choice in hemodynamically stable patients with blunt abdominal trauma because it has been shown to be accurate in defining solid and hollow visceral injury as well as visualizing retroperitoneal structures (pancreas, kidneys, aorta, vena cava, and retroperitoneal portions of the duodenum and colon) and the vertebral column. The accuracy of CT for bowel and mesenteric injury has improved in the last decade as faster CT detectors that produce fewer artifacts and thinner slices have been developed (20,21). A number of authors have reported using the latest generation of CT to identify active abdominal hemorrhage possibly requiring immediate surgical intervention (22). CT offers valuable information in a time when nonoperative management is used in greater than 80% of solid organ injury in children with blunt trauma (23,24). For these reasons, in many medical centers CT scanning has all but eclipsed DPL in the evaluation of children who are victims of abdominal trauma (25,26).

CT scanning, however, is not universally available on an emergent basis and has its limitations, visualizing solid organ injury better than hollow visceral and diaphragm injury. CT scanning requires transportation of the patient from the resuscitation area and, in many centers, completely out of the emergency department (ED). Once the patient is on the CT scanner table, the management of emergent problems becomes more difficult. For these reasons, some patients are too unstable to undergo this procedure.

Because DPL, CT scanning, and US may provide different types of information, they may be considered complementary (27,28). Notably, before any imaging technique or DPL is undertaken, the surgeon who will be responsible for the patient should be contacted and offered the opportunity to participate in the initial evaluation of the patient.

In the case of blunt trauma, DPL has traditionally been used to detect intra-abdominal bleeding in the hemodynamically unstable child unresponsive to appropriate resuscitation. It is most useful in the hypotensive child who is going to the operating room for urgent nonabdominal surgery when US is not available or produces equivocal results. Some have advocated using DPL in detecting bowel and mesenteric injuries, which are uncommon in blunt trauma but difficult to detect by CT scanning. DPL has been used traditionally to detect free hemorrhage or intestinal contents as evidence of potential bowel or mesenteric injury and is considered by some to be diagnostically superior to evaluation by CT (29).

DPL is used in the evaluation of penetrating thoracoabdominal and abdominal trauma to detect peritoneal penetration and serves as an adjunct to local wound exploration. DPL has an accuracy rate of 90% for diagnosing injury when using the cell counts as described for blunt abdominal trauma (30). With the increased incidence of hollow viscus and diaphragm injury from stab wounds, some authors have recommended using lower RBC counts (5,000/mm³ for low chest and 20,000/mm³ for anterior abdomen) because there is less blood loss with these injuries (31). If DPL lavage fluid does not exit the wound and contains fewer cells than the previously described thresholds, the child can be observed. Laparotomy is no longer considered mandatory for all abdominal stab wounds (32).

Gunshot wounds to the abdomen usually require exploration; the destructive force of firearms places the patient at
great risk for significant injury. However, in some cases the bullet pathway is tangential to the abdomen, and peritoneal penetration is not apparent. Local wound exploration of gunshot wounds is rarely conclusive. In such situations, DPL may be helpful in making this determination (33).

The only absolute contraindication to DPL exists when its performance would delay surgical management of a patient for whom such intervention is clearly indicated. Relative contraindications are severe obesity, infection, previous abdominal surgery, coagulopathies, and second- or third-trimester pregnancy. Adhesions from prior abdominal surgery can compartmentalize the peritoneal cavity, leading to iatrogenic bowel perforation or inability to recover an adequate volume of fluid for interpretation. If DPL must be done, the physician should choose the abdominal position (supraumbilical versus infraumbilical) farthest from the previous incision using an open technique. If the physician feels that DPL is necessary in a pregnant adolescent, the supraumbilical approach is recommended. Ultrasound has obvious advantages for the pregnant patient because it allows evaluation of the fetus and involves no radiation exposure. The patient with a pelvic fracture should have the procedure using the open technique 1 to 2 cm above the umbilicus to avoid the hematoma commonly associated with this injury.