In patients who require one-lung ventilation (OLV) and present with the dilemma of a difficult airway, such as the morbidly obese patient, the primary goal after appropriate airway anesthesia is achieved, is to establish an airway with a single-lumen endotracheal tube placed orally with the aid of a flexible fiberoptic bronchoscope while the patient is awake [23
]. In select patients who seem easy to ventilate by a mask, intubation can be performed with an Airtraq laryngoscope or with a video laryngoscope [24
]. Video laryngoscopy clearly can allow visualization of the pharynx, epiglottis, and vocal cords, plus visualization of the passage of the single-lumen endotracheal tube after induction of anesthesia.
An alternative when securing the airway prior to placing a lung separation device is the use of a laryngeal mask airway with the aid of a flexible fiberoptic bronchoscope; single-lumen endotracheal tube can be passed through the laryngeal mask airway. When using a large size laryngeal mask airway and passage of a single-lumen endotracheal tube size 6.5
mm ID is recommended. The use of the laryngeal mask airway C Trach has been reported to be an efficient airway device for ventilation and tracheal intubation in case of a difficult airway in morbidly obese patients [25
]. However, the potential for airway trauma may be higher with this exchange technique.
Bronchial blockers can be used following anesthesia induction and after the airway has been secured with a single-lumen endotracheal tube. The common bronchial blockers used through a single-lumen endotracheal tube include the Arndt blocker (adult sized 7.0 and 9.0
F), the Cohen endobronchial blocker (size 9.0
F), the Fuji Uniblocker (size 9.0
], the Univent tube, or the EZ blocker [26
]. displays the Arndt blocker. One advantage of one-time intubation with a single-lumen endotracheal tube is that it allows for the conversion to OLV with insertion of the bronchial blocker and simple removal of this at the end of a procedure if postoperative ventilatory support is needed [27
]. When a bronchial blocker is used, specifically size 9.0
F, the smallest acceptable single-lumen endotracheal tube size recommended is 8.0
mm ID. However, if a smaller single-lumen tube is used then a 7
F Arndt blocker is recommended. It is important to have enough space between the bronchial blocker and the flexible fiberoptic bronchoscope so navigation can be achieved with the single-lumen endotracheal tube. To achieve OLV the bronchial blocker must be advanced to the bronchus where lung collapse is required. Once the blocker is within the bronchus and the patient is turned into the lateral decubitus position, the inflation of the endobronchial balloon should be done under direct vision with the aid of a flexible fiberoptic bronchoscope while the lung is not ventilated. The amount of air needed to achieve a complete seal within the bronchus in adults ranges between 5 and 8
mL of air. The optimal position of a bronchial blocker in the left bronchus is when the blocker's balloon outer surface is seen at least 10
mm below tracheal carina inside the blocked bronchus. For the use of a right-side bronchus the depth on insertion of the blocker and balloon will depend upon the anatomical distance between the tracheal carina and the orifice of the right upper lobe bronchus. The optimal positions for all bronchial blockers should be confirmed with a flexible fiberoptic bronchoscope [28
]. displays the proper position of a bronchial blocker seen with fiberoptic bronchoscopy. It is our personal experience and opinion that in the obese patient in order to expedite lung collapse the center channel of the bronchial blocker should be attached to wall suction for a few minutes, this maneuver will facilitate lung collapse. After OLV is completed and the surgical procedure has ended, if postoperative mechanical ventilation is needed, withdrawal of the bronchial blocker ensues, leaving the single-lumen endotracheal tube in place.
The proper position of a bronchial blocker seen with fiberoptic bronchoscopy.
A common problem with the use of the bronchial blockers is that malpositions occur more often than with the DLTs [4
]. Potential complications related to the use of the bronchial blocker might include inclusion of a bronchial blocker or the nylon guide wire into the stapling line [29
]. This is why communication with the surgical team regarding the placement of a bronchial blocker in the surgical side is crucial. Removal of the guide wire in the Arndt blocker is mandatory prior to establishment of OLV. displays the characteristics of the bronchial blockers.
Characteristics of the bronchial blockers.