title: Evaluation of patient-related and procedure-related factors contributing to pneumothorax following thoracentesis.
abstract: OBJECTIVE
  To evaluate patient-related and procedure-related risk factors for thoracentesis-related pneumothorax.
  
  
  METHODS
  Prospective, nonrandomized cohort study.
  
  
  METHODS
  Pulmonary Special Procedures Unit of a university medical center.
  
  
  METHODS
  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 3(1/2)-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status, critical illness, effusion size or type, presence of loculations, operator, needle type, amount of fluid withdrawn, occurrence of dry tap, and type of thoracentesis were not associated with an increased frequency of pneumothorax.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 thoracentesis.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Pulmonary and Critical Care Medicine Division, University of California, San Diego Medical Center/Thornton Hospital, La Jolla 92037, USA. hcolt@ucsd.edu
authors.forename: H G
authors.initials: HG
authors.lastname: Colt
authors.forename: N
authors.initials: N
authors.lastname: Brewer
authors.forename: E
authors.initials: E
authors.lastname: Barbur
mesh_terms: D015505:Chest Tubes; D015331:Cohort Studies; D004322:Drainage / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000628:therapy; D016066:Pleural Effusion, Malignant / Q000628:therapy; D011030:Pneumothorax / Q000453:epidemiology / Q000209:etiology*; D011446:Prospective Studies; D011677:Punctures / Q000009:adverse effects / Q000295:instrumentation; D012307:Risk Factors