“Is it a full moon out?” your charge nurse asks as she takes the 5th EMS patch in the last hour. “We have two more traumas en route, and there are 4 patients that need to be seen at the door by our triage doc. Our beds are full and the hallways are getting awfully crowded…” You are all too familiar with the expectant look she just used to punctuate her statement, and you know that it is imperative for you and your team to start opening beds immediately. “All hail the full moon!” you chant as you walk briskly over to your ED team that night.
As you rally your department to start trouble-shooting patient dispositions, your senior resident approaches you with three cases he states are “ready to go”. The first two are a husband and wife who were in a low speed motor vehicle collision the day before. They came into today to get “checked out” and they both checked out just fine. The x-rays ordered through triage were completely normal, and the happy couple looks eager to be discharged. You help answer some of their lingering questions while your resident finishes up the discharge paperwork for the third patient he has for you.
After passing along a few teaching pearls, you tell your resident you are ready to hear about his next patient. His 3rd case is a 21 year-old female who came into the ED today for vaginal spotting, nausea, and mild abdominal cramping. She had normal vital signs and a benign physical exam. The labs he sent were normal except for a serum hCG of 91,000 mIU/mL. Her blood type is O+ and her wet prep looked normal. He got her abdominal cramping under control with PO Tylenol and she was able to drink plenty of fluid for her bedside ultrasound in the ED.
“I found her IUP without any problems and she’s about 9 3/7 weeks along.” he states as he pulls up her ultrasound images and videos for you to review. “The fetal heart rate measured at 167 bpm and her adnexae look great. She has no free fluid and the ultrasound went really smoothly.” He has her scheduled for an appointment with your OB clinic later this week and her discharge paperwork is burning a hole in his hand.
You review his bedside ultrasound images and video clips and pause to ponder over a couple of his images.
What do you see in figures 1 and 2? Do you need to have a different discussion with your patient?
Dx: Forgotten IUD
As you review the resident’s images and videos, you note that there is a hyperechoic object adjacent to the gestational sac. At first, you thought it might just be some artifact but there is definitely an acoustic shadow farfield (posterior) to the hyperechoic object (Figure 3). You ask your resident whether or not he noticed the subtle finding during his scan and what he thinks it could possibly be. During your discussion, you see the light bulb turn on inside your resident’s head and you go with him back to the room to reassess the patient. You watch with pride as your resident sits down on the stool next to the bed and gently asks the patient if she has ever had an IUD before. It’s clear to everyone in the room that the patient had forgotten about that “minor detail” until that moment when she was prompted. On further review, the patient remembers having an IUD placed for her 16th birthday, but just thought that “they dissolve away after some time.” Your resident grabs the ultrasound machine and performs a transabdominal scan so he can show the patient what we are concerned about on her scan. He fans through the uterus and shows her the live IUP again. He then sweeps through the entire uterus and finds a clear transverse view of the IUD imbedded adjacent to the gestational sac (Figure 4).
The OB team comes down to see the patient and explains the risks and benefits of leaving the IUD in place. They have arranged for close outpatient follow up and recommend a comprehensive ultrasound through radiology as an outpatient to follow the pregnancy and IUD. You debrief your resident and give him some pearls to use and pitfalls to avoid during his next patient encounter. “I guess I just stopped scanning once I found what I was looking for…” he contemplates out loud. You put a reassuring hand on his back, give him a comforting smile, and remind him that mistakes are the portals of discovery. Now go out there and enjoy all the mayhem we will be blessed with during this full moon. Just don’t let me see another anchor in our department tonight!
Pearls & Pitfalls for Pelvic Ultrasound
- Bedside ultrasound can provide you with valuable data to help you make critical diagnoses and expedite patient care. Be careful not to fall into the common trap of using it just to find information that fits your clinical impression. Premature closure prevents you from considering other alternative possibilities. Just because something fits doesn’t mean it’s right.
- Novice sonographers may perform a cursory scan through a gallbladder and save images of an empty lumen because they don’t feel the patient has cholelithiasis, even when they might. Their personal bias limits the usefulness of their scan results.
- With experience, a seasoned sonographer may find those subtle gallstones or intraluminal polyps on that same scan that could have easily been missed secondary to anchoring heuristic error.
- When you are performing pelvic ultrasound, make sure you scan through the entire organ of interest in multiple planes. Often times, subtle and useful findings are seen in the periphery of a comprehensive scan.
- It is even more important to be comprehensive when you don’t know what you are looking for. Patients and their presentations will surprise you. Maintain an open mind and inquisitive nature during each patient encounter.
- During the pelvic scan, always begin with a transvaginal scan to obtain a general overview of yout patient’s anatomy. Use a 3-5 MHz curvilinear or phased array transducer for transabdominal imaging. Remember that a full urinary bladder provides a great acoustic window for the transabdominal scan.
- Have your patient empty her bladder for the endovaginal portion of the scan. Apply a copious amount of gel over the intracavitary transducer (ICT) and then cover the probe and gel with a transducer sheath or condom. Apply another layer of bacteriostatic surgical gel on the outside of the transducer sheath at the tip of the probe.
- Insert and advance the transducer with the indicator marker pointing anteriorly towards the patient’s pubic symphysis. Alternatively, you may let the patient insert the probe herself as this method is often less uncomfortable.
- Scan through the entire pelvis in both the transverse and longitudinal planes. Don’t prematurely terminate your scan just because you find the answer you are looking for early on. Unexpected findings may lie in the periphery.
- Be consistent, comprehensive, and critical of the images you obtain.