Recommendations on the Use of Ultrasound Guidance for Adult Thoracentesis: A Position Statement of the Society of Hospital Medicine

Journal of Hospital Medicine 13(2). 2018 February;:126-135 | 10.12788/jhm.2940

January 26, 2018|Journal of Hospital Medicine

Ria Dancel, MD;Daniel Schnobrich, MD;Nitin Puri, MD;Ricardo Franco-Sadud, MD;Joel Cho, MD;Loretta Grikis, MLS;Brian P. Lucas, MD, MS;Mahmoud El-Barbary, MD, PhD, MSc;SHM Point of Care Ultrasound Task Force;And Nilam J. Soni, MD, MS

EXECUTIVE SUMMARY: 1) We recommend that ultrasound should be used to guide thoracentesis to reduce the risk of complications, the most common being pneumothorax. 2) We recommend that ultrasound guidance should be used to increase the success rate of thoracentesis. 3) We recommend that ultrasound-guided thoracentesis should be performed or closely supervised by experienced operators. 4) We suggest that ultrasound guidance be used to reduce the risk of complications from thoracentesis in mechanically ventilated patients. 5) We recommend that ultrasound should be used to identify the chest wall, pleura, diaphragm, lung, and subdiaphragmatic organs throughout the respiratory cycle before selecting a needle insertion site. 6) We recommend that ultrasound should be used to detect the presence or absence of an effusion and approximate the volume of pleural fluid to guide clinical decision-making. 7) We recommend that ultrasound should be used to detect complex sonographic features, such as septations, to guide clinical decision-making regarding the timing and method of pleural drainage. 8) We suggest that ultrasound be used to measure the depth from the skin surface to the parietal pleura to help select an appropriate length needle and determine the maximum needle insertion depth. 9) We suggest that ultrasound be used to evaluate normal lung sliding pre- and postprocedure to rule out pneumothorax. 10) We suggest avoiding delay or interval change in patient position from the time of marking the needle insertion site to performing the thoracentesis. 11) We recommend against performing routine postprocedure chest radiographs in patients who have undergone thoracentesis successfully with ultrasound guidance and are asymptomatic with normal lung sliding postprocedure. 12) We recommend that novices who use ultrasound guidance for thoracentesis should receive focused training in lung and pleural ultrasonography and hands-on practice in procedural technique. 13) We suggest that novices undergo simulation-based training prior to performing ultrasound-guided thoracentesis on patients. 14) Learning curves for novices to become competent in lung ultrasound and ultrasound-guided thoracentesis are not completely understood, and we recommend that training should be tailored to the skill acquisition of the learner and the resources of the institution.

RESULTS

Literature search

A total of 1,556 references were pooled from the following four different sources: a search by a certified librarian in September 2015 (1066 citations) that was updated in November 2016 (165 citations) and again in August 2017 (9 citations), working group members’ literature searches (47 citations), and a search focused on training (269 citations). The final selection included 94 articles that were abstracted into a data table and incorporated into the draft recommendations. The details of the literature search strategy are given in Appendix 3.

Recommendations

Four domains (clinical outcomes, technique, training, and knowledge gaps) with 20 draft recommendations were generated based on an initial review of the literature. The quality of evidence was appraised after assigning references to each draft recommendation. After two rounds of panel voting, five recommendations did not achieve agreement based on the RAND rules (failure of achieving a threshold of at least 70% and/or uncertainty expressed by panel median voting in the uncertain region),¹⁴ and 15 statements received final approval. The degree of consensus based on the median score and the dispersion of voting around the median are shown in Appendix 5. Ten statements were approved as strong recommendations, and five were approved as conditional recommendations. Recommendation 3 was deleted due to its similarity to the first two statements. This yielded a final recommendation count of 14. For each recommendation, the strength of the recommendation and the degree of consensus are summarized in Table 1.

Terminology

Thoracentesis is a procedure of aspiration of fluid from the pleural space by percutaneous insertion of a needle through the chest wall with or without the insertion of a catheter.
In this document, ultrasound guidance refers to static guidance and site marking performed at the bedside immediately before the procedure, as opposed to real-time (dynamic) ultrasound guidance or radiology performed site marking. The static method is the most commonly used method of ultrasound guidance and is supported by current evidence.

RECOMMENDATIONS

Clinical Outcomes

1.We recommend that ultrasound should be used to guide thoracentesis to reduce the risk of complications, the most common being pneumothorax.

Rationale: Both static ultrasound guidance and dynamic ultrasound guidance have been reported to be associated with a reduced risk of pneumothorax.^4-7,15-18 A meta-analysis of 24 studies that included 6,605 thoracenteses showed a significant decrease in the risk of postprocedure pneumothorax with the use of ultrasound guidance compared to the risk associated with thoracentesis performed based on landmarks alone (OR 0.3, 95% CI 0.2–0.7).³ The meta-analysis included both prospective and retrospective studies conducted using both static and dynamic ultrasound guidance.³ A large retrospective cohort study conducted by Mercaldi et al. comprising more than 61,000 patients who underwent thoracentesis also showed that ultrasound guidance was associated with reduced odds of pneumothorax (OR 0.8 [0.7–0.9]).⁴ When pneumothorax did occur during that hospitalization, the cost of hospitalization increased by $2800 and the length of stay increased by 1.5 days.⁴ A 2008 review of 19,339 thoracenteses conducted by Patel et al. also demonstrated an association between ultrasound guidance and reduced odds of pneumothorax (OR 0.8 [0.7–0.96]).¹⁸ Although these findings were significant, it is important to note that the studies of both Mercaldi et al. and Patel et al. were reviews of administrative databases conducted using the International Classification of Diseases, 9th Revision (ICD-9) codes for thoracentesis and Current Procedure Terminology–4^th edition (CPT) codes for the use of ultrasound.^4,18 Patel et al. identified pneumothorax using ICD-9 codes for “pneumothorax–iatrogenic” and “pneumothorax–not specified as due to the procedure.” The association between ultrasound guidance and the reduced odds of pneumothorax was driven by the latter code.¹⁸ However, as with most retrospective studies using administrative data, granular data about the patients, procedure, proceduralists, and complications were not available in these reviews and conclusions may be limited by erroneous coding or documentation.^4,18 In a third retrospective cohort study, Raptopoulos et al. compared 154 landmark-based thoracenteses performed by “clinical physicians” and 188 ultrasound-guided thoracenteses performed by radiologists and found that ultrasound-guided site selection reduced the rate of pneumothorax from 18% to 3% (P < .0001).⁶ Finally, one single-center randomized controlled trial of 160 thoracenteses performed by pulmonologists showed that ultrasound guidance reduced the relative risk of pneumothorax by 90% (12.5% vs 1.3%; P =.009) with a number needed to treat of 9.¹⁵ It was not possible to blind the operators to the use of ultrasound guidance, but the data analysis was blinded.¹⁵ Furthermore, while there was no explicit comparison of the intervention vs. the control groups, randomization would have presumably rendered both groups similar in terms of patient characteristics and effusion characteristics.¹⁵ Ultrasound may reduce the risk of pneumothorax through several mechanisms, including identifying patients in whom thoracentesis cannot be safely performed, allowing selection of the safest needle insertion site, and revealing the optimal depth of needle insertion.