Recommendations on the Use of Ultrasound Guidance for Adult Abdominal Paracentesis: A Position Statement of the Society of Hospital Medicine
1. We recommend that ultrasound guidance should be used for paracentesis to reduce the risk of serious complications, the most common being bleeding.
2. We recommend that ultrasound guidance should be used to avoid attempting paracentesis in patients with an insufficient volume of intraperitoneal free fluid to drain. 3. We recommend that ultrasound guidance should be used with paracentesis to improve the success rates of the overall procedure.
4. We recommend that ultrasound should be used to assess the volume and location of intraperitoneal free fluid to guide clinical decision making of where paracentesis can be safely performed.
5. We recommend that ultrasound should be used to identify a needle insertion site based on size of the fluid collection, thickness of the abdominal wall, and proximity to abdominal organs.
6. We recommend that the needle insertion site should be evaluated using color flow Doppler ultrasound to identify and avoid abdominal wall blood vessels along the anticipated needle trajectory.
7. We recommend that a needle insertion site should be evaluated in multiple planes to ensure clearance from underlying abdominal organs and detect any abdominal wall blood vessels along the anticipated needle trajectory.
8. We recommend that a needle insertion site should be marked with ultrasound immediately before performing the procedure, and the patient should remain in the same position between marking the site and performing the procedure.
9. We recommend that using real-time ultrasound guidance for paracentesis should be considered when the fluid collection is small or difficult to access.
10. We recommend that dedicated training sessions, including didactics, supervised practice on patients, and simulation-based practice, should be used to teach novices how to perform ultrasound-guided paracentesis.
11. We recommend that simulation-based practice should be used, when available, to facilitate acquisition of the required knowledge and skills to perform ultrasound-guided paracentesis. 12. We recommend that competence in performing ultrasound-guided paracentesis should be demonstrated prior to independently performing the procedure on patients.
© 2019 Society of Hospital Medicine
2. We recommend that ultrasound guidance should be used to avoid attempting paracentesis in patients with an insufficient volume of intraperitoneal free fluid to drain.
Rationale. Abdominal physical examination is not a reliable method for determining the presence or volume of intraperitoneal free fluid, as no specific physical examination finding has consistently shown both high sensitivity and specificity for detecting intraperitoneal free fluid.11,12,20,31,47-51 Patient factors limiting the diagnostic accuracy of physical examination include body habitus, abdominal wall edema, and gaseous bowel distention.
In comparative studies, ultrasound has been found to be significantly more sensitive and specific than physical examination in detecting peritoneal free fluid.11,12 Ultrasound can detect as little as 100 mL of peritoneal free fluid,52,53 and larger volumes of fluid have higher diagnostic accuracy.53-55 In one randomized trial of 100 patients suspected of having ascites, patients were randomized to landmark-based and ultrasound-guided paracentesis groups. Of the 56 patients in the ultrasound-guided group, 14 patients suspected of having ascites on physical examination were found to have no or an insufficient volume of ascites to attempt paracentesis.20 Another study with 41 ultrasound examinations on cancer patients suspected of having intraperitoneal free fluid by history and physical examination demonstrated that only 19 (46%) were considered to have a sufficient volume of ascites by ultrasound to attempt paracentesis.38
3. We recommend that ultrasound guidance should be used for paracentesis to improve the success rates of the overall procedure.
Rationale. In addition to avoiding drainage attempts in patients with an insufficient volume of intraperitoneal free fluid, ultrasound can increase the success rate of attempted procedures by localizing the largest fluid collection and guiding selection of an optimal needle insertion site. The success rates of landmark-based paracentesis in patients suspected of having intraperitoneal free fluid by physical examination are not well described in the literature, but multiple studies report success rates of 95%-100% for paracentesis when using ultrasound guidance to select a needle insertion site.20,38,56,57 In one randomized trial comparing ultrasound-guided versus landmark-based paracentesis, ultrasound-guided paracentesis revealed a significantly higher success rate (95% of procedures performed) compared with landmark-based parancentesis (61% of procedures performed). Moreover, 87% of the initial failures in the landmark-based group underwent subsequent successful paracentesis when ultrasound guidance was used. Ultrasound revealed that the rest of the patients (13%) did not have enough fluid to attempt ultrasound-guided paracentesis.20
Technique
4. We recommend that ultrasound should be used to assess the characteristics of intraperitoneal free fluid to guide clinical decision making of where paracentesis can be safely performed.
Rationale. The presence and characteristics of intraperitoneal fluid collections are important determinants of whether paracentesis, another procedure, or no procedure should be performed in a given clinical scenario. One study reported that the overall diagnostic accuracy of physical examination for detecting ascites was only 58%,50 and many providers are unable to detect ascites by physical examination until 1L of fluid has accumulated. One small study showed that at least 500 ml of fluid must accumulate before shifting dullness could be detected.58 By contrast, ultrasound has been shown to reliably detect as little as 100 mL of peritoneal free fluid 52,53 and has been proven to be superior to physical examination in several studies.11,12 Therefore, ultrasound can be used to qualitatively determine whether a sufficient volume of intraperitoneal free fluid is present to safely perform paracentesis.
