Relevant pelvic pathology that can be encountered in the intensive care unit (ICU) setting, and is amenable to bedside ultrasound evaluation, may be split into three general categories. The first is a source of blood loss and will most typically include ectopic pregnancy, hemorrhagic cyst, or mass. The second is a source of infection and is most likely to include pelvic inflammatory disease and tubo-ovarian abscess. The third is a source of pain apart from the first two categories including ovarian cysts, masses, and ovarian torsion.
Sonographic pelvic anatomy can be challenging and, depending on the ultrasound technique utilized, anatomical relationships may appear confusing. The uterus, a pear-shaped muscular organ typically measuring 6–8 centimeters (cm) in length and 4 cm in width, is bordered anteriorly by the bladder and posteriorly by the rectum. The uterus comprises the fundus, body, and cervix, where it narrows and protrudes into the vagina (Figure 25.1). The fallopian tubes exit the uterus on either side of the uterine fundus at the level of the cornua. The anterior cul-de-sac is a potential space between the uterus and bladder, while the posterior cul-de-sac (pouch of Douglas) is between the uterus and rectum. With the patient supine, the pouch of Douglas is the most dependent part of the pelvis and is typically the first area to collect fluid such as blood or pus. The fallopian tubes extend laterally from the cornua in the broad ligament. An ovary attaches to the broad ligament posteriorly on each side. The iliac artery and vein run posterior and lateral to the ovaries and the two are a major landmark sonographically.
A normal uterus is seen in long axis on ultrasound. B indicates body of uterus; C, cervix; F, fundus of uterus.
The pelvic ultrasound examination is split into two distinct types that are not mutually exclusive, and one may lead to the other depending on the pathology discovered. The easiest is the transabdominal (TAS) pelvic ultrasound examination. It is performed utilizing a curved linear array with a typical frequency range of 5–2.5 MHz. The broad field of view afforded by this type of transducer is ideal for surveying the pelvis. In general, the TAS pelvic ultrasound examination requires a full bladder. In the case of many ICU patients, this simply means clamping the urinary catheter. An alternative is to fill the bladder with either sterile saline or to simply hold up the catheter bag and have some of the urine flow back into the bladder. The ideal volume that allows the bladder to act as an optimum acoustic window will vary from patient to patient. Approximately 350 milliliters (mL) will be ample in most cases and it is possible to overfill the bladder and actually move organs of interest farther away from the transducer. Similar to the pelvic portion of the focused assessment ...