One lung ventilation (OLV) is frequently used in thoracic surgery to promote surgical exposure and improve operative conditions. At this time, there are two different approaches to OLV in routine use in adult thoracic surgery. One approach is to use of a double lumen tube (DLT). The other approach is to use a bronchial blocker (BB). Currently there are several different types of bronchial BBs on the market.
The EZ-Blocker essentially functions as a bronchial blocker with a 7-Fr shaft with two separate occlusive balloons coming off this shaft in a "Y" configuration designed to rest on the carina. Once anchored in place the operator can choose to inflate one of the two occlusive balloons to isolate one main stem bronchus or the other.
A number of studies have been performed comparing BBs to DLTs looking at time and ease of placement, differences in quality of lung isolation, and incidence of sore throat, hoarseness, and other morbidity associated with placement. A recent meta-analysis published by Clayton-Smith et al found that BBs are associated with fewer airway injuries when compared to DLTs. They found the quality of isolation to be equivalent between BBs and DLTs. While quality of isolation over all may be comparable, it has been demonstrated in several studies that positional stability of bronchial blockers such as the Arndt or Cohen, is frequently inferior to that of a DLT.
At this time, there are a small number of trials looking at the use of the EZ-blocker in adult patients. In one study published in 2013 the EZ-blocker was compared to the Cohen Flex-Tip blocker. In this study they found that time to place the EZ-blocker was in fact shorter and that overall the number of repositioning required was less with the EZ-blocker. In 2013, a study was published by Mourisse et al which compared DLT to the EZ-blocker. In this study they found initial malposition of both devices to be fairly equivalent, and time to placement was longer with the EZ-blocker. They also found more tracheal and bronchial injuries in the DLT group, but importantly they found that positional stability was equivalent. In both of these studies however they did not design their studies to effectively differentiate between right and left sided procedures when quantifying the need for BB repositioning. Because the takeoff of the right upper lobe bronchus is sometimes adjacent to, or proximal to the carina, it can impede effective isolation with a BB. Therefore, claims of positional stability may rely heavily on the laterality of the procedure, with right sided isolation being significantly more labile than left sided especially with respect to isolation using a BB.
According to the manufactures recommendations the EZ-blocker is placed through a Y-piece adaptor included with the blocker kit. A flexible fiberoptic bronchoscope (FFB) is placed in a separate limb of this Y-piece and this fed through alongside the EZ-blocker to visualize and confirm placement of the BB. The balloon is then inflated typically under direct vision to occlude that bronchus thus isolating that lung hopefully achieving full lung isolation.
In conclusion then, the study team feels that the potential morbidity of a DLT in terms of the potential for airway injury when compared to a BB suggests that further exploration of the possibility of equivalent positional stability between these devices is necessary. The team also feels that it is necessary to delineate the impact of laterality on the effectiveness of one technique for isolation versus the other.
In addition to this if there is a difference in stability in cases where right sided isolation via the EZ-blocker fails in the setting of multiple repositions or out and out failure the team would like to examine the preoperative high resolution CT data to determine if there are anatomic measurement which could potentially inform the appropriateness or inappropriateness of choosing a DLT over an EZ-blocker.
