Factors associated with increased risk of pneumothorax:
(1) more than 1 pass of the needle (multiple needle sticks)
(2) aspiration of air
(3) clinical suspicion of pneumothorax
(4) patient history of thoracic radiation
Factors not associated with an increased risk of pneumothorax
(1) gauge of needle
(2) volume of aspirate
(3) level of physician training
Evaluation of patients with one of the factors associated with pneumothorax:
(1) study group: 110 patients undergoing 174 thoracentesis procedures
(2) 110 films would not have been performed (63% reduction), of which 109 were negative, and 1 showed a minor pneumothorax
(3) 8 of 9 pneumothoraces after thoracentesis were detected in post-procedural radiographs performed on the remaining patients
(4) hemothorax was not detected on the post-procedure radiographs
