Efficacy and safety of Cohen Flex-Tip blocker and left double lumen tube in lung isolation for thoracic surgery: a randomized comparative study

Background
The Cohen blocker is one of the lung isolation devices. Unfortunately, most anesthesiologists believe that its efficacy in inducing lung collapse is less than that of the double-lumen tube (DLT). This study has been performed to compare the adequacy of lung collapse and the adverse effects between the Cohen blocker and the left DLT for thoracic operations.
Method
Forty patients with an age range of 25–50 years and American Society of Anesthesiologist (ASA) physical status I-II of either sex were subjected to an elective thoracic operation with lung isolation achieved by either a left DLT or a Cohen blocker. The patients were distributed randomly into two equal groups ( = 20): group (I) left DLT and group (II) Cohen-blocker. The following parameters were measured: the number of intubation attempts, time for correct positioning, and lung collapse assessment grades either spontaneous (grade 1), assisted with suction (grade II), or with manual disconnection maneuver (grade III). Sore throat and hoarseness were compared between the two groups.
Results
The first intubation attempt success rate was 90% and 95% ( = 0.871), while the second attempt success rate was 10% and 5% ( = 0.617) in the left DLT and Cohen blocker groups, respectively (non-significant value). The time for correct positioning was significantly shorter in the left DLT group than in the Cohen blocker group ( < 0.001). Lung collapse showed similar results between the two groups ( = 0.803) regardless of the grade of lung collapse: either spontaneous (grade I), assisted with suction (grade II), or with manual disconnection maneuver (grade III). The left DLT group showed a significantly higher frequency of hoarseness ( = 0.017) and sore throat ( = 0.028) than the Cohen blocker group.
Conclusion
We concluded that Cohen blocker can be used as a good alternative to the left DLT for its efficiency in inducing lung collapse with minimal incidence of postoperative hoarseness and sore throat.