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General Articles: Case Report

The Cohen Flexitip Endobronchial Blocker: An Alternative to a Double Lumen Tube

Cohen, Edmond MD

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doi: 10.1213/01.ANE.0000184116.86888.D9
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In recent years, the increase in popularity of video-assisted thoracoscopic surgery (VAT) is attributed to the considerable number of diagnostic and therapeutic procedures that can be performed with this approach. During VAT, one-lung ventilation (OLV) is essential for providing an optimal view of the operative field, as well as for facilitating palpation of lesions in the lung parenchyma (1). The “gold standard” procedure is to provide OLV with a double-lumen endotracheal tube (DLT). However, the DLT is designed for a normal upper airway and bronchial tree and is poorly adaptable to abnormal anatomy or placement in a patient with a difficult airway. With increasing need for use of OLV, the limitations of traditional DLTs, including difficult insertion and positioning, have become evident. This has led to renewed interest in devising alternative methods of achieving lung separation, particularly by means of an independent bronchial blocker (BB) (2–4). This report describes the technical features and clinical use of a new tip-deflecting BB (Cohen Tip Deflecting Endobronchial Blocker, Cook Critical Care, Bloomington, IN).

The Cohen blocker is designed for use as an independent BB passed through a standard single-lumen endotracheal tube (ETT) with a 4.0-mm external diameter fiberoptic bronchoscope (FB) (Figure 1)

Figure 1.
Figure 1.:
A) Schematic presentation of the Cohen Blocker. The blocker is 65 cm long and comprises a 3-cm soft nylon tip. The soft, flexible tip can be deflected more than 90 degrees achieved by a counterclockwise rotation of the wheel positioned at the proximal end of the blocker. Turning the wheel 180 degrees deflects the tip 90 degrees. Deflection is in the direction of the wheel, indicated by an external marker and also an arrow near the tip as a fiberoptic landmark. B) The Cohen Blocker.

The blocker has a 9F external diameter and contains a central lumen with a 1.6-mm diameter. The blocker comprises a firm (70 durometer) 62-cm shaft bonded to a 3-cm soft nylon deflecting tip (40 durometer) easily directed into the desired bronchus. The lumen may be used for limited suctioning or insufflation of oxygen to the collapsed lung in case of hypoxia. A 2-cm external plastic sleeve (gripper) improves manual control of blocker tip rotation during placement or repositioning.

The soft, flexible tip of the BB can be deflected more than 90 degrees by a counterclockwise rotation of the wheel positioned at the proximal end of the shaft. Deflection is to one side only and in the direction of the wheel (external marker) and also a black arrow near the tip (fiberoptic landmark).

The cuff is a high-volume, low-pressure balloon. When inflated it has a spherical “pear” shape and provides both a good seal and generous contact with the bronchial wall. Average inflation volume, under direct fiberoptic visualization, is 5–8 mL depending on the bronchial size. The cuff is blue, which contrasts sharply with the bronchus and makes fiberoptic identification easy.

The Cohen blocker kit contains an Arndt Multi-Port Adaptor (Cook Critical Care, Bloomington, IN), that permits simultaneous ventilation, fiberoptic bronchoscopy, and manipulation of the BB with an airtight seal. Alternatively, a standard swivel adaptor may be used (Mallinckrodt, Pleasanton, CA or Portex, Keene, NH). When using the standard swivel adaptor, the blocker’s plastic sleeve (gripper) may be passed into the hole in the adaptor’s membrane to prevent air leak.

The BB should first be placed through the adaptor before insertion into the ET. Right mainstem blockade is generally simple, as the blocker tends to naturally select the right bronchus. The balloon should be positioned and then inflated. A 7.0-mm ETT is the smallest size that the blocker and a 4-mm FB can simultaneously pass through. To facilitate the insertion through a small ETT, the blocker cuff should first advance beyond the tip of the ETT followed by the insertion of the FB. To block the left main bronchus, the blocker should be inserted with the wheel facing to the left. The FB is positioned at the distal end of the ETT tube to provide a clear view of the carina. The blocker is advanced beyond the tip of the ETT. While holding the grip, the blocker is adjusted to have the black arrow facing the left. Finally, by rotating the wheel clockwise, the tip of the catheter will have left deflection and is simply advanced into the left mainstem bronchus. If the flexed tip will not enter the left main bronchus, the blocker can be manipulated by turning the catheter at the gripper. Because of the flexibility of the tip of the blocker, it can be directed to block a selective lobar bronchus, or even a smaller segment if necessary.

Case Report

A 67-yr-old male with a history of resection of laryngeal carcinoma with bilateral neck dissection and muscle-skin flap reconstruction was scheduled for lung biopsy using left VAT to exclude laryngeal metastasis. Because of the previous surgery and radiation, his mouth opening was limited to 2 cm. His diet consisted of liquid and blended food through a straw. In the operating room, the airway was anesthetized with a mist of lidocaine 4%. An awake oral fiberoptic endotracheal intubation with a 7.5-mm single-lumen ETT was achieved with the tube loaded over a 4.0-mm video bronchoscope (Olympus, Melville, NY). After induction of general anesthesia, the Cohen Flexitip endobronchial blocker was inserted through a swivel adapter (Portex, Keene, NH) and passed alongside the videoscope inside the ETT lumen. The blocker was advanced and, as expected, was easily directed into the right mainstem bronchus (RMB). The blocker tip was withdrawn to about 2 cm above the carina. Using the grippe, it was rotated to align the black arrow to the left. The wheel was then turned to deflect the tip towards the left and advanced into the left main bronchus. An endoscopic view of the insertion is shown in Figure 2. The wheel was then rotated back to its neutral position (aligning the 2 dots) and the balloon was inflated under direct fiberscopic vision using 6 mL of air.

Figure 2.
Figure 2.:
Positioning of the blocker into the left main bronchus: an endoscopic view. Upper left: the blocker is inserted under endoscopic view and is entering the right main bronchus because of the anatomical structure of the bronchial tree. Upper right: the tip is pulled above the carina with the black arrow position toward the left. Lower left: the wheel is rotated and the tip is deflected to the left. Lower right: the blocker is pushed into the left main bronchus.

The patient was placed in the right lateral decubitus position and placement of the blocker cuff was reconfirmed. The blocker lumen was connected to wall suction to enhance the collapse of the left lung and provide a quiet surgical field. The ventilation setting was changed from 600 mL × 10 to 500 mL × 12 to maintain end-tidal CO2 between 28–30 mm Hg with a peak airway pressure of 32 cm H2O, The Spo2 was between 95% and 97% during OLV. The lung was well collapsed and provided an excellent operative condition for the surgeon. Wedge resection of a left lower lobe lesion was performed and confirmed to be metastatic from the laryngeal carcinoma. At the conclusion of the surgical procedure the blocker balloon was deflated, the lung was expanded and the blocker was removed. The patient was not fully awake to meet tracheal extubation criteria and was endotracheally extubated 3 h later in the postanesthesia care unit. His recovery and discharge were uneventful.


OLV can be achieved with methods other than the use of DLTs such as the Fogarty embolectomy catheter. (Edwards Lifesciences, Irvine, CA). However, these catheters lack a directing mechanism or a suction lumen and have a high pressure, low volume occlusion balloon (5).

Lung separation can also be accomplished with a Univent® tube that combines a single lumen tube with a BB (Univent, Fuji Systems Corp., Tokyo, Japan) (6–8). It has the advantage common to all BBs: it is a single-lumen tube and there is no need to change the tube at the end of the procedure if postoperative ventilatory support is required. This is particularly important in cases of difficult endotracheal intubation, prolonged surgery with airway edema, and massive fluid replacement. However, the external diameter of the Univent tube is quite large relative to the internal diameter, which makes it difficult to pass between the vocal cords. The blocker can dislocate during surgical manipulation and satisfactory bronchial seal and lung separation are sometimes difficult to achieve (9).

The above problems were addressed by the development of a snare-guided BB, (Arndt; Cook Inc., Bloomington, IN), that passed over the FB into the selected bronchus (10–11). The snare is then removed and a 1.4-mm lumen may be used as a suction port or for oxygen insufflation. The disadvantage of the Arndt device is the inability to reinsert the snare once it has been pulled out, thus losing the ability to redirect the blocker if necessary. The blocker is advanced along the FB blindly and may be engaged at the level of the ETT Murphy eye or at the tracheal carina. Finally, the external diameter is 9F, which requires a minimum 8.0-mm ETT to be able to accommodate the deflated cuff of the BB when it is passed over the FB.

In one study, the effectiveness of these devices to provide lung isolation during elective thoracic procedures was evaluated (12). A left-sided DLT (Mallinckrodt Medical) was compared with the torque control blocker Univent and the Ardnt blocker. Results demonstrated that these devices were equally effective. The Arndt blocker took longer to position and, because of the limited size of the suction lumen, more time was needed to collapse the lung. A recent review of the progress in lung separation was published in the surgical literature (13).

With time, it has become obvious that modern thoracic anesthesiologists need an alternative to the DLT for the following reasons: First: DLTs are non-friendly and, being bulky, are often difficult to insert and position. Second: the use of DLTs is associated with the need to change the tube to a single tube if the patient requires postoperative ventilatory support. Third: a patient airway that is considered easy for insertion of a single-lumen tube may represent a challenge for a DLT insertion. The growing number of VAT procedures increases the likelihood of requiring lung separation in a patient who has a difficult airway in whom placing a DLT may be difficult or impossible. Finally, depending on the extent and duration of the procedure, an airway initially not classified as difficult may become difficult secondary to facial edema, secretions, and laryngeal trauma from the initial intubation. In these cases, when planning to provide lung separation, the postoperative period must be considered.

In summary, the clinician should be able to master the different methods of lung separation and become familiar with the available devices. A new BB that has a tip-directing mechanism (deflecting tip) with a patent 1.6-mm suction lumen is described. The author has used the device successfully in many situations, including right-sided thoracotomy and through a tracheostomy.


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© 2005 International Anesthesia Research Society