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

2.We recommend that ultrasound guidance should be used to increase the success rate of thoracentesis.

Rationale: Thoracentesis guided by ultrasound has lower rates of failed attempts, or “dry taps,” compared to thoracentesis guided solely by physical examination. In 1977, Ravin described a method of using ultrasound to guide successful drainage of six complex pleural effusions (empyema or loculated effusion) after multiple (5–7) failed attempts by clinicians using physical examination alone.⁸ In a second study by radiologists, Weingardt et al. demonstrated that 20 of 26 failed landmark-based thoracenteses were due to incorrect site selection by physical examination–15 sites were below the diaphragm and 5 sites were above the pleural effusion or in the consolidated lung–and the use of ultrasound allowed successful sampling in 14 of 16 patients who had a failed landmark-based thoracentesis.⁹ Diacon et al. asked 30 physicians, ranging from junior housestaff to pulmonologists, to mark 172 potential thoracentesis sites in 67 patients with pleural effusions using physical examination alone. Ultrasound was then used to evaluate the proposed puncture sites. They found that using ultrasound would have avoided puncture on “dry chests” in 2% and avoided potential laceration of a solid organ in 10% of patients compared to site selection by physical examination alone.¹⁹ Finally, Perazzo et al. randomized 160 patients to landmark-based thoracentesis and ultrasound-guided thoracentesis and demonstrated that half of the eight dry taps that occurred in the control group could be successfully drained using subsequent ultrasound guidance.¹⁵

Technique

3. We recommend that ultrasound-guided thoracentesis should be performed or closely supervised by experienced operators.

Rationale: Current evidence suggests lower complication rates when thoracentesis is performed by experienced healthcare providers. A systematic review of 6,605 thoracenteses showed a significantly lower pneumothorax rate when thoracentesis was performed by pulmonology or radiology faculty versus resident physicians (3.9% vs 8.5%; P =.04), although this finding was not significant in the four studies that directly compared this factor.³ In a quality improvement study performed by Duncan et al., pulmonology and critical care physicians combining multiple quality improvement initiatives to achieve and maintain competency decreased the rate of pneumothorax from 8.6% to 1.1% (P =.0034).²⁰ Interventions included ultrasound training, performance of 10 thoracenteses under expert supervision, and restriction of privileges to proceduralists who perform 10 or more thoracenteses per year.²⁰ Finally, a series of 9,320 ultrasound-guided thoracenteses performed or supervised by a single expert internist over a period of 12 years resulted in a pneumothorax rate of 0.6% and a composite complication rate of 0.98% (pneumothorax, reexpansion pulmonary edema, hemothorax, site bleeding, hematoma, splenic laceration, and vasovagal reaction).²¹ Notably, pneumothorax rate in resident physician hands was reported to be 8.5% in the meta-analysis performed by Gordon et al., which is similar to the initial rate in the pulmonologists who participated in the study by Duncan et al.^3,20 However, after instituting formal ultrasound training and other initiatives aimed at maintaining competency, the pneumothorax rate in the study by Duncan et al. decreased to 1.1%, similar to the rate observed in the series by Ault et al.²¹ This suggests that training and supervision are necessary to achieve competency and reduce the rate of complications.^3,20,21

4. We suggest that ultrasound guidance be used to reduce the risk of complications from thoracentesis in mechanically ventilated patients.

Rationale: The rest of this guideline refers to ultrasound-guided thoracentesis performed in spontaneously breathing patients; however, this recommendation is specific to mechanically ventilated patients. Two prospective observational studies have shown no increase in complications when ultrasound-guided thoracentesis is performed on mechanically ventilated patients compared to patients not receiving positive pressure ventilation. A feasibility study of 45 thoracenteses performed on ventilated patients reported no complications,²² whereas another study on 232 patients reported a pneumothorax rate of 1.3%.²³ In a larger study conducted by Mayo et al., medicine housestaff performed thoracentesis under the supervision of intensivists who had undergone training in ultrasound prior to performing the procedure.²³ In both studies, most of the patients were in a supine position, although positioning and puncture site were at the discretion of the physician, and both studies employed use of static ultrasound guidance.^22,23 A large series of 9,320 ultrasound-guided thoracenteses that included 1,377 mechanically ventilated patients did not report a higher rate of pneumothorax (0.8%) compared to that in spontaneously breathing patients (0.61%).²¹ Finally, a meta-analysis of 19 observational studies comprising 1,124 mechanically ventilated patients who underwent pleural drainage procedures showed a low rate of pneumothorax (3.4%) and hemothorax (1.9%).²⁴ Although the rate of complication was reported to be low in this meta-analysis, ultrasound was not employed in all studies and its use was not associated with a significant reduction in pneumothorax.²⁴ This may be because 8 of the 19 studies used pigtail catheters or large-bore thoracostomy tubes which treat pneumothorax as they occur.²⁴