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Pearls & Pitfalls for Ultrasound-Guided Suprapubic Aspirations
1.Bladder aspiration via the suprapubic approach can be performed using anatomical landmarks or direct ultrasound guidance. Studies have shown that ultrasound guidance helps maximize the chances of a successful tap, meanwhile minimizing the risk of complications such as peritoneal or bowel injury.
2. Minimize your chances of a dry tap or a procedural complication. Before starting, utilize bedside ultrasound to determine whether or not there is sufficient anechoic urine in the bladder to perform a successful suprapubic bladder aspiration. If the bladder appears empty or contracted, encourage fluid intake and repeat the scan after some time has passed.
3. Use a phased array or curvilinear transducer to map out the urinary bladder and surrounding organs using a suprapubic approach. Although it is possible to perform an ultrasound-guided bladder aspiration using endovaginal views, in most clinical scenarios, a suprapubic scan will be more comfortable for the patient and easier for the practitioner.
4. Prior to starting, prep the skin with chlorhexidine (preferred) or betadine. A small amount of local anesthetic may be used depending on physician and/or patient preference. Remember to prep and cover your ultrasound transducer in a sterile fashion before performing an aspiration under dynamic ultrasound guidance. The entire procedure should be performed in a completely sterile fashion.
5. If sterile probe sleeves are temporarily unavailable, use a sterile glove as a substitute sleeve instead. Gel packets (such as Surgilube) can also be used in lieu of other commercially available sterile ultrasound gels when supplies are running low.
6. Ultrasound can be used to help visualize the needle trajectory and location during the aspiration process. During the procedure, angle your needle so that it bisects the ultrasound beam a few centimeters below the skin’s surface. Check this in two perpendicular planes to best position your needle tip right in the center of the bladder, thus minimizing the chance of complications. Determine the needle’s course and trajectory by observing tissue movement and artifacts such as ring down.
7. If you are using a smaller gauge needle, or if the patient possesses a thick bladder wall, you will observe a slight compression of the hyperechoic bladder wall before you feel the “pop” of the needle entering into the bladder lumen.
8. If you are having difficulty aspirating fluid, scan through the bladder in multiple planes to determine the exact position of the needle tip. To ensure that you are not abutted against a fold or side of the bladder wall, gently withdraw or reposition the needle while continuously pulling back on the syringe plunger. Scan through the entire bladder to help determine the redirection angle.
9. Remember that Practice Makes Proficient: With bedside ultrasound there is no substitute for experience.
Brady Pregerson manages a free online EM Ultrasound Image Library and is the editor of the Emergency Medicine Pocketbook series. For more information visit ERPocketBooks.com
Teresa Wu is the EM Ultrasound Director and Co-Director for Simulation Based Training for the Maricopa Emergency Medicine Program in Phoenix, Arizona.