A Structural Complication in the Torque Control Blocker Univent®: Fracture of the Blocker Cap Connector

Field: Medicine (Health Sciences)

To the Editor: The Univent® endotracheal intubation tube (Vitaid, Lewiston, NY) is used to achieve lung isolation (1). The tube has a single lumen with a separate in-line bronchial blocker channel to pass an attached balloon catheter that, when inflated, will obstruct the intended bronchus. When the bronchial blocker is not in use, it is fully retracted and closed with a blocker cap connector to prevent air leakage during ventilation. Design improvements were made in 2001, and the new device is referred to as the Torque Control Blocker Univent® (TCB). The new tube is latex-free, and the blocker channel is now flexible to enhance blocker guidance into the target bronchus. We report two cases in which the TCB bronchial blocker cap connector was detached or fractured during use. Case 1: A 48-year-old man underwent a thoracoscopic left upper wedge biopsy. After physical examination of the oropharynx and laryngoscopic inspection, an 8.0-mm I.D. TCB was placed. In the usual fashion, flexible fiberoptic bronchoscopy was performed to guide the placement of the bronchial blocker. We then placed the patient into the lateral decubitus position for the intended surgical procedure. During repositioning, a portion of the blocker cap detached from the main tube element (Fig. 1). This piece was reattached to the blocker. During the operation, no air leaks were detected. Lung isolation was achieved and maintained without further incident.Figure 1: A detached blocker cap from the bronchial blocker.Case 2: A 75-year-old woman was scheduled for resection of a right upper lung mass. A 7.0-mm I.D. TCB was chosen. While closing the blocker cap connector, it broke into two pieces (Fig. 2). It was considered to be unusable at that point, and a second TCB of the same dimensions was opened and placed. The remainder of the procedure was without incident.Figure 2: A fractured blocker cap.Manufacturers continuously redesign technology to facilitate use and improve patient safety. With the original Univent®, there were reports of complications: cap dislodgement from the tip of the bronchial blocker (2) and fragmentation of the tube inner wall (3,4). We report that the TCB Univent® is demonstrating problems as well. In Case 1, we admit that there may have been undue stress placed on the blocker connector while turning the patient, but this should be accounted for in the design of the tube. The majority of thoracic patients requiring lung isolation must be turned for their intended thoracic procedures, and thus this would be unavoidable. In Case 2, there was no trauma to the tube or to the connector. The connector simply fractured during normal use. When considering the cost of the TCB (acquisition cost at The University of Iowa Hospitals and Clinics is $137), it is somewhat more expensive than the other tubes available for one-lung ventilation. We have identified two tubes (of the first 50 TCB tubes we have used) with connector problems. At this point, we are unsure of the frequency of this problem, but in a high-volume practice, a 4% rate of connector problems can lead to greater costs and delays in the operating room. There do not seem to be any safety issues, but we are concerned. We recommend that the manufacturer redesign the bronchial blocker and connector into a single and flexible piece. We look forward to these additional improvements. Javier H. Campos, MD Kemp H. Kernstine, MD, PhD