How many types of bronchial blockers are available? What are the advantages and disadvantages of bronchial blockers?
Answer:
Several blockers are available, leaving ample preference of choice to the operator and the institution. Advantages and disadvantages of blockers are listed in Table 2.3.
Fogarty embolectomy catheters (Edwards Lifesciences, Irvine, CA) can be used to isolate the lung, although not specifically made for this purpose. No. 7 French (7F) Fogarty catheters come with either a 12- or 20-mL high-pressure, low-volume balloon in both latex and nonlatex models. They have a metallic stylet that can be bent to facilitate endobronchial placement. In the case of dislodgment, the stylet can be reinserted and the blocker repositioned. Fogarty catheters have no communicating central channel; therefore, continuous positive airway pressure (CPAP) or suction cannot be applied intraoperatively. Lung collapse occurs by absorption of oxygen. Therefore, prior to inflating the balloon, it is recommended to both discontinue ventilation and depressurize the circuit of the ventilator if the patient tolerates it. The catheters are usually placed outside a single-lumen ETT and positioned via fiberoptic bronchoscopy (Fig. 2.1A). If placed inside the ETT, a connector such as a two-swivel adaptor is needed to facilitate insertion of both the catheter and a bronchoscope.
Arndt blockers (Cook Medical Inc, Bloomington, IN) (wire-guided endobronchial blocker) are available in no. 5, 7, and 9 French with elliptical or spherical cuffs (low pressure, high volume), the latter particularly advantageous to isolate the right lung. They are usually inserted through the ETT via a three-way connector (catheter, bronchoscope, ventilation circuit). Their positioning is facilitated via Seldinger technique by an inner wire with a loop at the distal tip, where the flexible bronchoscope is placed. The wire is then removed once the blocker is in position, leaving an inner lumen that allows for suctioning or CPAP. Once the wire loop has been removed, it can be reinserted, allowing repositioning of the blocker in case of dislodgment.
Cohen blockers (Cook Medical Inc, Bloomington, IN) are similar in shape to the Arndt blockers, but they use a positioning wheel to facilitate placement. By turning the wheel in a clockwise fashion, the distal portion of the blocker deflects to the left. The main advantage of this blocker is its placement in the left mainstem because of its steep angle. Disadvantages include the cost, the fragility of the wheel, and the availability of only one size (no. 9 French).
EZ-blockers (Teleflex Life Science Ltd, Morrisville, NC) are blockers with a Y-shaped bifurcation at the end fitted with two inflatable cuffs and a hollow channel in the center. The cuffs are high-pressure, low-volume, and color-coded. The blocker is placed inside the ETT, with the end on a horizontal plane to facilitate the placement of the Y across carina. Final position needs be confirmed via fiberoptic visualization because both cuffs may go in the right mainstem. The main advantage of this blocker is its stability, making it useful in cases where patient access is limited. The presence of the two cuffs makes sequential lung isolation feasible.
Univent tubes (Teleflex, Triangle Park, NC) consist of an ETT with a built-in silicone bronchial blocking catheter. The main advantage is the ability of leaving the device in place in case of postoperative mechanical ventilation. However, this device is not commonly used in the United States because of its bulkiness. The outer diameter ranges from 9.7 to 13.7 mm (for a 6.0 to 8.0 inner diameter tube), with the potential to cause subglottic edema and stenosis in case of long-term use. The inner diameter is quite narrow, making suctioning or fiberoptic bronchoscopy difficult. The silicone blocker in the Univent is available as an isolated item (Fuji blocker). It is a high-volume, low-pressure system with a preformed 'hockey stick' bend at the tip and a double stylet. It has a spherical cuff (ideally more suited to isolate the right mainstem bronchus) and two different sizes (no. 5 and 9 French). The Coopdech blocker (Daiken Medical Co Ltd, Izumi, Japan) is similar in shape to the Fuji blocker but offers the extra option of an auto-inflate balloon via an auto-inflate button, allowing the use of one hand while maneuvering the fiberoptic bronchoscope.
Blockers can be used to rescue nonworking DLT, by placing the device inside the lumen of the nondependent lung. This may be needed in case of rupture of the bronchial cuff in a patient already positioned, or for lobar collapse in case of DLT dislodgment and inability to appropriately reposition in the mainstem bronchus. The DLT may be left in the original place or withdrawn and used as a single-lumen tube.
Reference(s):
- Campos JA. Lung isolation. In: Slinger P, ed. Principle and Practice of Anesthesia for Thoracic Surgery. Cham, Switzerland: Springer; 2019:283-309.
- Gropper MA, Cohen NH, Eriksson LI, et al, eds. Miller’s Anesthesia. 9th ed. Philadelphia, PA: Elsevier; 2020:1663-1700.
- Lee GK. Airway apparatus for thoracic surgery. Anaesth Intensive Care Med. 2014;15:499-504.
- Licker M, Le Guen M, Diaper J, et al. Isolation of the lung: double-lumen tubes and endobronchial blockers. Trends Anaesth Crit Care. 2014;4:47-54.