Catching an Ectopic Pregnancy on Bedside Ultrasound
Image 1 is of the most important place to start scanning when you are worried about intra-abdominal bleeding. It shows Morrison’s pouch in between the liver capsule and the right kidney. This is usually the most dependent area of the abdomen in a supine patient. Sometimes blood won’t actually push this far back, and the anechoic fluid is actually seen a bit more anteriorly, or only at the inferior tip of the liver. In this image though, the blood appears black and has moved all the way back to the posterior part of the hepatorenal recess. When the fluid stripe reaches about 1cm in width, it corresponds to approximately one liter of intraperitoneal free fluid.
Image 2 is the pelvis shown longitudinally with the indicator pointing toward the patient’s head (cephalad). Just posterior to the bladder, you see a dark heterogeneous area, which looks suspicious. It does not look like really dark anechoic free fluid like you are used to seeing with acute intraperitoneal bleeding, but you are concerned because there is so much of it. As you fan through, you notice that the blood is not only collecting in the anterior cul-de-sac (as seen in Image 2), but also in the posterior cul-de-sac. You obtain careful transabdominal views of the uterus, and note that the uterus is empty and there is no sign of an intrauterine pregnancy. As you are trying to find the adnexa on a transabdominal view, the patient’s urine dip comes back positive for beta-hCG.
Your suspicion is confirmed. Your stoic patient who initially said, “I have terrible gas pains,” really meant to say, “Help me, can’t you see I’m bleeding to death.” In a case like this, you don’t need to, and shouldn’t, wait for the pregnancy test to come back before calling in your OB surgeon. The patient may have a ruptured hemorrhagic ovarian cyst or a ruptured ectopic pregnancy. Either way, she needs operative intervention with that amount of free fluid in her pelvis. Call your consultant early and let them “own” the rest of the time spent before she goes upstairs. Getting the surgeons involved early can help expedite patient care, and once they physically see the patient, they may be prompted to make different decisions based on their own clinical gestalt. It’s hard to argue with black and white images of a large amount of intraperitoneal free fluid.
As with most ectopic pregnancies, they turn south, and typically, very quickly. Fortunately for this patient, she was resuscitated with blood and rushed to surgery where they found a ruptured ectopic and four liters of blood in her abdomen. Maintaining a high level of suspicion and performing a bedside ultrasound ultimately saved this patient’s life.
Continue to next page for Pearls and Pitfalls