Objective: To evaluate patient-related and
procedure-related risk factors for thoracentesis-related
Design: Prospective, nonrandomized
Setting: Pulmonary Special Procedures
Unit of a university medical center.
Thoracentesis using either a 22-gauge, a Boutin, or a Cope needle
(depending on availability and operator preference) was performed by
the pulmonary faculty or by pulmonary physicians-in-training under
faculty supervision. In order to control for effusion size and the
presence of loculations, chest radiography and pleural ultrasonography
were performed prior to each thoracentesis. Potential patient-related
and procedure-related risk factors for pneumothorax were analyzed at
the procedure level using the presence or absence of pneumothorax on
the postprocedure chest radiograph as the sole outcome variable.
Results: Two hundred fifty-five thoracenteses were
performed in 205 adult patients (113 men and 92 women; mean age,
58.8 ± 18 years) over a 31/2-year period. One hundred fifty
procedures were performed for diagnostic purposes, 28 procedures were
performed for therapeutic purposes, and 77 procedures were performed
for both diagnostic and therapeutic purposes. Based on the radiographic
criteria, 152 effusions (60%) were small. Loculations were present in
76 patients (30%). Pneumothoraces occurred in 14 instances (5.4%),
and chest tube drainage was required in 2 instances (0.78%).
Hospitalization status, critical illness, effusion size or type,
presence of loculations, operator, needle type, amount of fluid
withdrawn, occurrence of dry tap, and type of thoracentesis were not
associated with an increased frequency of pneumothorax. The only
predictor variable demonstrating statistical significance was repeated
Conclusion: The results of a bivariate
analysis suggest that pneumothorax following thoracentesis is a rare
event that is not easily predictable when the procedure is performed by
experienced operators in a controlled setting.