During thoracentesis procedures, misplaced and multiple needle insertions can increase the risk of adverse events, including pneumothorax. Bedside ultrasound has variety of potential uses and can improve the safety of needle insertion procedures.


To determine whether use of ultrasound during thoracentesis reduces the risk of pneumothorax, as well as estimate healthcare utilisation due to pneumothorax events in thoracentesis patients.


Using data available from 2007-2008, we conducted an observational cohort study using the Premier Perspective automated hospital database. The cohort included patients identified as having a thoracentesis procedure (via ICD-9 and CPT codes) who were not at increased risk of pneumothorax due to other conditions or procedures. Ultrasound guidance was determined where the patient had a charge for ultrasound on the same service day as the thoracentesis procedure. Pneumothorax outcomes were identified via ICD-9 codes. Adjusted risk of pneumothorax was estimated using multivariate logistic regression, controlling for baseline variables that altered the odds ratio (OR) for ultrasound guidance by >10%. Total hospitilisation cost and length of stay (LOS) were estimated for patients with and without pneumothorax using multivariate ordinary least squares (OLS) regression of natural log-transformed values and retransformed back to the original scale using Duan’s smearing estimate.

1United BioSource Corporation, Bethesda, MD, 2SonoSite Inc., Bothell, WA,3University of Southern California, Los Angeles, CA


A total of 61,261 thoracentesis patients met all study inclusion criteria. Comparison groups included 26,838 (44%) patients with ultrasound guidance and 34,423 (56%) patients without. The overall rate of pneumothorax was 2.7%. After adjusting for confounding factors, the OR for pneumothorax was 0.81 (95% CI: 0.74-0.90). A pneumothorax increased the total cost of hospitilisation by $2,752 (P<0.001) and LOS by 1.4 days (P<0.001).


In this study, ultrasound guidance was associated with a 19% reduction in pneumothorax following thoracentesis procedures. Pneumothorax events resulted in longer hospital stays and increased hospitilisation costs. This economic benefit of ultrasound guidance has not been demonstrated previously in a large, general population study.