CHAPTER 139 Culdocentesis (Colpocentesis)
Culdocentesis is a procedure for female patients designed to detect and sample free fluid in the peritoneal cavity. The classic application of this test is for the diagnosis of hemoperitoneum due to ruptured ectopic pregnancy, but it can also be used to detect acute pelvic inflammatory disease and to sample ascites. Modern imaging modalities, such as ultrasonography, have greatly reduced the need to perform culdocentesis, but occasionally in an emergency or where imaging resources are unavailable, culdocentesis can be extremely useful—even life-saving.
The cul de sac is the lowest point in the abdominal cavity of a woman (when upright). The tissue septum between the posterior fornix of the vagina and the posterior cul de sac consists of vaginal mucosa, peritoneum, and little else. It is about 1 cm in thickness and contains no major blood vessels or organs. Thus, a needle introduced from the vagina into the cul de sac can easily access free fluid in the peritoneal cavity (Fig. 139-1).
Ruptured ectopic pregnancy is the classic indication. Signs and symptoms of ruptured ectopic pregnancy include amenorrhea, abdominal pain with rebound tenderness, vaginal bleeding, shoulder pain, and a positive pregnancy test. Hemodynamic instability and acute anemia may be present. On speculum examination the posterior fornix of the vagina may bulge into the vagina from the weight of the blood behind it. This 3-minute test can offer definitive proof of hemoperitoneum requiring immediate surgery.
Acute salpingitis can also be diagnosed by culdocentesis. This is the only means, short of abdominal surgery, to obtain pus from within the abdominal cavity for diagnosis and culture.
A mass (e.g., a neoplasm, an abscess, an endometrioma, or an unruptured ectopic pregnancy, whose rupture could be harmful) in the cul de sac is an absolute contraindication.
Equipment and Supplies
The equipment for culdocentesis is simple and should be available in any emergency department or medical office with gynecologic capabilities (Fig. 139-2). The following are required:
The instruments should be sterile and gloves should be used to perform the procedure. Face mask and drapes are unnecessary.