Pearls & Pitfalls
1. Use a high-frequency intracavitary transducer to image the peritonsillar area. Be sure to adequately clean the probe and cover the probe with a protective sheath prior to use in a patient’s oral cavity, as this probe is also used for transvaginal exams.
2. When referring to the probe in front of the patient, for obvious reasons, please remember to use the term “intracavitary probe” instead of “transvaginal probe”.
3. Having the patient insert the transducer on their own can help minimize the gag reflex elicited during the procedure. Once the probe has been inserted by the patient, gently guide the face of the transducer until it is resting over the area of interest.
4. Although a peritonsillar aspiration is best performed under direct ultrasound guidance, the space limitations of the oropharynx and associated trismus may make it impossible to have the ultrasound probe and needle inserted at the same time. If it is not possible to perform an ultrasound-guided needle aspiration, use the ultrasound to confirm that a PTA is present, determine if there are multiple pockets present, and estimate the depth of it’s most fluctuant pocket(s).
5. Take advantage of depth markers on the right of the ultrasound image. You can use these marks to estimate the depth of the abscess and the depth of the carotid artery. The depth of the scan (in cm) is indicated by the number on the bottom right of the screen. In general, the large hashmarks are 1 cm apart and the smaller hasmarks are 0.5cm apart. You can use this information to appropriately size your needle guard and guide your needle advancement during the procedure.
6. Always scan around to try to identify adjacent vascular structures. The carotid artery typically lies 2.5 cm deep to the mucosal surface. Once you find a dark, hypoechoic vascular structure, you can use color or spectral Doppler to determine if it is a vein or an artery. Plan your procedure so that you minimize your chances of accidentally puncturing any adjacent vessels.
7. Become familiar with the orientation marker on your intracavitary probe and set up your ultrasound machine so that the indicator marker is on the left side of the image before you begin the procedure. Maintaining the proper orientation will enable you to identify what you are scanning in a quicker and more accurate fashion, and help you complete the procedure in a more timely manner.
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written by James , January 30, 2013