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

13. We suggest that novices undergo simulation-based training prior to performing ultrasound-guided thoracentesis on patients.

Rationale: Simulation-based training for thoracentesis has been studied in providers with different levels of medical training, ranging from medical students and internal medicine residents to practicing pulmonologists. Studies suggest that training in a zero-risk environment with simulation task trainers leads to increased knowledge and skills without subjecting the patients to inexperienced operators.^85-87 One study on simulator-based training in medical students showed skill retention at 6 months and these skills were at least partially transferred to increased competency on live patients.⁸⁸ Checklists to train providers in ultrasound-guided thoracentesis have been published.^89,90 An experiential training program for attending physicians that utilized task trainers, along with standardized equipment and procedural technique, resulted in a reduction in the pneumothorax rate from 8.6% to 1.1%.²⁰

14. Training curves for novices to become competent in lung ultrasound and ultrasound-guided thoracentesis are not completely understood. We recommend that training should be tailored to the skill acquisition of the learner and the resources of the institution.

Rationale: Understanding the rates at which novices progress from performing procedures under direct supervision to performing them independently would be highly desirable to ensure patient safety, guide supervision, and maximize efficiency of training. However, there is limited research describing the rate of progression of learners through these stages, either with regard to time or number of procedures performed. Two studies have shown that with brief training programs, medical students⁸⁸ and internal medicine residents⁸⁷ can achieve high levels of proficiency to perform thoracentesis on simulators, which is durable over time; however, whether these findings in a simulated environment translate into clinically significant outcomes is largely unknown, and neither of these studies incorporated the use of ultrasound guidance in their training curricula.^87,88 Another study of pulmonary and critical care physicians combined multiple quality improvement initiatives with a half day of ultrasound-guided thoracentesis training, a requirement to perform 10 supervised thoracenteses prior to independent practice, and an additional requirement to perform 10 thoracenteses per year to maintain privileges.²⁰ These interventions resulted in a concentration of competency among a few proceduralists, decreasing the rate of pneumothorax from 8.6% to 1.1%.²⁰ Degradation of skills with disuse may also occur⁸⁴; thus, procedures performed infrequently should at a minimum be subjected to increased supervision and/or retesting.

The process of developing these guidelines revealed important gaps in the literature regarding the use of ultrasound guidance for thoracentesis. First, it is uncertain whether the use of ultrasound reduces the risk of bleeding with thoracentesis. A retrospective cohort study of 19,339 thoracenteses suggests that ultrasound guidance is associated with a 38.7% relative reduction in the odds of hemorrhage, although this reduction did not reach statistical significance (OR 0.6 [0.4–1.04]).¹⁸ Ultrasound may reduce the risk of bleeding by reducing the number of attempts and needle passes and potentially avoiding tortuous intercostal vessels, which can be found especially in elderly patients and more cephalad rib spaces.⁹¹ In an observational study of 22 patients undergoing thoracentesis, the intercostal artery (ICA) was identified by a high-frequency ultrasound transducer in 74 of 88 intercostal spaces.⁹² The ICA is more exposed in the intercostal space within the first 6 cm lateral to the spinous processes and can be seen as far lateral as the midaxillary line.^92-95 Thus, the ICA will most likely be avoided if a procedure site is selected >6 cm lateral to the spinous processes and the needle is inserted above the rib.

Second, although all three studies conducted using real-time (dynamic) ultrasound guidance reported a pneumothorax rate of <1%, it is uncertain whether real-time ultrasound guidance confers any additional benefit compared to static guidance for site marking as direct comparisons were not made.^17,96,97 It is possible that real-time ultrasound guidance may be superior to static guidance in certain situations, such as small pleural effusions of <10–15 mm that have historically been considered too small to tap.^13,22,23,96

Third, although one study suggests that general internists can safely perform thoracentesis with low complication rates similar to those of interventional radiologists,² limited data exists on how to train practicing hospitalists to use ultrasound to guide thoracentesis. The effectiveness of different training protocols to acquire competence in ultrasound-guided thoracentesis has not been compared.

Finally, the impact of ultrasound use on patient experience has yet to be explored.

The use of ultrasound guidance for thoracentesis has been associated with increased success rates and decreased complication rates. Ultrasound can be used to estimate the pleural fluid volume, characterize the effusion as simple or complex, identify an optimal needle insertion site, and reduce the need for postprocedural chest radiographs. Training and experience are essential to reap the benefits of using ultrasound for thoracentesis, although our understanding of optimal educational strategies and learning curves is limited. Once training has occurred and competence is achieved, hospitalists can perform ultrasound-guided thoracentesis as safely as radiologists, pulmonologists, and other specialists.