Peritoneal lavage is a procedure in which fluid is introduced into the abdominal cavity and then drained back out. It has two very different purposes. In diagnosis, it was once used to detect internal bleeding after trauma. In treatment, it is used to wash out the abdomen during surgery or infection. The two are not the same thing, and confusing them is common.
What Is Peritoneal Lavage Procedure Uses And Types?
The peritoneum is the thin membrane that lines the inside of your abdomen and covers most of the organs within it. It forms a kind of closed sac. Peritoneal lavage means putting fluid into that space and then removing it.
What the fluid is for depends on the goal. In diagnostic peritoneal lavage, a small amount of sterile fluid is instilled and then allowed to drain. If it comes back bloody, that suggests bleeding inside the abdomen. In therapeutic peritoneal lavage, much larger volumes of fluid are used to physically wash the cavity — removing bacteria, debris, or inflammatory chemicals.
There is also a third context where the term appears: peritoneal dialysis. This uses the peritoneum as a filter to remove waste products from the blood in people with kidney failure. It is related in mechanism but is a distinct treatment, and it is not what most clinicians mean when they say “lavage.”
The word itself comes from the Latin for “wash.” That is the whole idea. Whether you are washing to find something or washing to remove something changes everything about how the procedure is done.
How Is Diagnostic Peritoneal Lavage Performed?
Diagnostic peritoneal lavage, often shortened to DPL, is performed at the bedside, usually in an emergency department or trauma bay. A small incision is made just below the navel. A catheter is threaded into the abdominal cavity.
If blood returns immediately through the catheter, the test is positive and the procedure stops there. If it does not, sterile fluid — typically normal saline or a similar balanced solution — is run in. The amount used is generally around 1 liter in adults. The fluid is then allowed to drain back out by gravity.
The drained fluid is examined. It may be sent for cell counts, tested for bile or bacteria, or checked for food particles. Certain findings indicate that surgery is likely needed.
The test is quick. It can be done in minutes. That speed was its main advantage for decades.
What Conditions Can Peritoneal Lavage Help Detect?
The classic use of DPL is detecting blood in the abdomen after blunt trauma — a car crash, a fall, a crush injury. The spleen and liver are the organs most often injured in blunt abdominal trauma, and both can bleed significantly without obvious external signs.
It can also detect hollow organ injury. If the intestine or stomach is torn, its contents leak into the abdominal cavity. DPL fluid may show bile, bacteria, or plant fibers from digested food. These findings suggest a perforation that needs surgical repair.
Other uses have included evaluating penetrating trauma to the abdomen and, less commonly, assessing suspected intra-abdominal infection. Some clinicians have used it to investigate unexplained abdominal pain, though this is uncommon in modern practice.
The test does not identify which organ is bleeding. It only tells you that something is. That limitation matters, because it means a positive result still requires imaging or surgery to localize the source.
Why Is Diagnostic Peritoneal Lavage Used Less Often Today?
Computed tomography, or CT, changed trauma care. A CT scan of the abdomen with contrast can show not just whether there is bleeding, but exactly where it is coming from and how severe it is. It can also show injuries to organs behind the peritoneum, which DPL cannot reliably detect.
CT is non-invasive. DPL requires an incision. CT gives surgeons a map. DPL gives them a yes-or-no answer.
Focused ultrasound, often called FAST (Focused Assessment with Sonography for Trauma), added another tool. It is fast, non-invasive, and can be repeated as a patient’s condition changes. It detects free fluid in the abdomen, which in trauma usually means blood.
Because of these alternatives, DPL has largely moved out of routine use in well-resourced trauma centers. It still appears in guidelines and training as an option when CT or ultrasound are unavailable, or when a patient is too unstable to leave the emergency department for imaging. In settings without advanced imaging, it remains a genuinely useful test.
That is an important distinction. A procedure falling out of favor in one setting is not the same as a procedure being useless everywhere.
What Is Therapeutic Peritoneal Lavage Used For?
Therapeutic lavage is used during surgery and in the treatment of certain abdominal infections. The goal is mechanical: wash out material that should not be there.
In peritonitis — inflammation of the peritoneum, often from a perforated bowel — surgeons may irrigate the abdominal cavity with large volumes of sterile fluid. This removes bacteria, stool, and inflammatory debris. It is part of the surgical treatment of the underlying problem, not a standalone cure.
In severe acute pancreatitis, the pancreas releases enzymes and inflammatory substances that can spread through the abdomen. Some treatment approaches have used peritoneal lavage to remove these. The evidence here is mixed. Some studies suggest benefit in selected patients; others have not confirmed a clear improvement in outcomes. It is not a standard treatment for all cases.
Lavage is also used in certain gynecologic and oncologic surgeries. In some cancer operations, fluid is collected from the abdomen and examined for cancer cells — a technique called peritoneal washing cytology. Finding cancer cells there changes staging and treatment planning.
During any open abdominal surgery, irrigation is routine. Surgeons wash the cavity before closing to reduce contamination. This is so standard that it is rarely described as a separate procedure.
What Are the Risks and Limitations?
DPL is not risk-free. The catheter can injure the bowel, bladder, or blood vessels. Infection is possible. In patients who have had prior abdominal surgery, scar tissue can make the procedure more difficult and more dangerous.
False negatives occur. A small amount of bleeding may not show up. Injuries to organs behind the peritoneum, like the pancreas or kidneys, may be missed entirely because the lavage fluid does not reach them well.
False positives also occur. Menstrual blood, minor liver trauma that would have stopped bleeding on its own, or a traumatic tap can all produce a positive result. That can lead to surgery that might not have been necessary.
Therapeutic lavage carries its own concerns. Large volumes of fluid can affect electrolyte balance and body temperature. In peritonitis, aggressive irrigation has been debated — some evidence suggests that too much manipulation of inflamed tissue may do more harm than good. Clinical practice varies.
No procedure in medicine is without trade-offs. The question is always whether the information or benefit is worth the risk for that specific patient.
How Does Peritoneal Lavage Compare to Peritoneal Dialysis?
These two are frequently confused because they both involve fluid in the abdominal cavity. They are not the same procedure.
| Feature | Peritoneal Lavage | Peritoneal Dialysis |
|---|---|---|
| Purpose | Diagnose bleeding or infection; wash out the abdomen | Remove waste and excess fluid in kidney failure |
| Fluid used | Sterile saline or balanced solution | Special dialysis solution with controlled glucose and electrolytes |
| Duration | Minutes to a single surgical session | Ongoing, repeated daily or nightly |
| Setting | Emergency department or operating room | Home or clinic, long-term |
| Catheter | Temporary, placed for the procedure | Permanent, surgically implanted |
Dialysis relies on the peritoneum’s ability to act as a semipermeable membrane. Waste products move from the blood into the dialysis fluid across that membrane, and the fluid is then drained. Lavage does not rely on this filtering property. It relies on physically flushing the cavity.
Someone on peritoneal dialysis is not undergoing lavage. Someone who has had a diagnostic lavage is not receiving dialysis. The shared anatomy is the only real overlap.
Is Peritoneal Lavage Still Relevant?
Yes, but in a narrower role than it once had. In trauma centers with CT and ultrasound, DPL is rarely the first choice. It remains valuable when those tools are unavailable or when a patient is too unstable to be moved.
Therapeutic lavage remains part of surgical practice. Irrigation during abdominal surgery is routine. Its role in conditions like severe pancreatitis is still debated, and the evidence does not support it as a universal treatment.
Peritoneal dialysis, meanwhile, is an established and widely used treatment for kidney failure. Millions of people worldwide use it. That is a different story from lavage, and it deserves to be understood on its own terms.
What ties all of these together is a simple idea: the abdominal cavity can be accessed, filled with fluid, and drained. What you do with that access — and what you learn from the fluid that comes back — is where the medicine lives.
Frequently Asked Questions
Is peritoneal lavage still used today?
Yes, though diagnostic peritoneal lavage is used far less often in trauma centers that have CT and ultrasound available. It remains an option when those tools are unavailable or when a patient is too unstable to leave the emergency department.
What is the difference between peritoneal lavage and peritoneal dialysis?
Lavage uses fluid to detect bleeding or to wash out the abdominal cavity, usually as a one-time procedure. Peritoneal dialysis uses the peritoneum as a filter to remove waste products from the blood in people with kidney failure, and it is done repeatedly over the long term.
What does a positive peritoneal lavage mean?
A positive result means the fluid that drained back out contained blood, bile, bacteria, or food particles. That finding suggests internal injury or infection and usually points toward surgery, though it does not identify which organ is involved.
Is peritoneal lavage painful?
The procedure involves an incision and catheter placement, so local or general anesthesia is typically used. Most patients do not feel the lavage itself, though discomfort at the incision site afterward is common.
