BACKGROUND: This study compared the modified BronchoCath double-lumen endotracheal tube (DLT) with the Univent bronchial blocker and Arndt's wire-guided endobronchial blocker (WEB) to determine whether there were objective advantages of one over the other during anesthesia with one lung ventilation. METHODS: Forty five patients having either thoracic or esophageal procedures were randomly assigned to one of three groups. Fifteen patients received a left-side DLT, 15 patients received a Univent tube, and 15 patients received a WEB. The following were studied: 1) time required to position each tube until satisfactory placement was achieved, 2) time required until lung collapse, 3) frequency of malpositions after initial placement with fiberoptic bronchoscopy, 4)surgical exposure ranked by surgeons blinded to type of tube used. RESULTS: Statistically significant differences were observed in time required to place the tube or blocker between the WEB (263.6 +/- 76.0 s), DLT (146.4 +/- 57.7 s, I < 0.0001) and Univent tubes (193.8 +/- 72.4 s, P = 0.0130). There were no significant differences in time to lung collapse, the frequency of malposition or surgical exposure. CONCLUSIONS: We conclude that the DLT, Univent tube, and WEB are useful for one lung anesthesia but it takes longer for the WEB to be placed safely than to place a DLT or Univent tube. The selection between the three tubes depends on type of surgery, difficulty of intubation, and familiarity of each tube by the anesthesiologist.