Chapter 20. Lung Isolation Devices

8/11/2019 Chapter 20. Lung Isolation Devices

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Chapter 20

Lung Isolation DevicesP.634

Indications for Lung Isolation

Tho rac i c P roc edu r es

A def la ted lung provides better operating conditions and reduced

trauma during thoracic procedures.

Con t r o l o f Con t am inat i o n o r Hem o r r hage

A lung isolation device can prevent infected material from one

lung from contaminating the other lung (1). W hen hemorrhage

occurs in one lung, an isolation device allows the unaffected lungto be ventilated (2,3,4,5,6,7,8,9,10,11).

Un i l a te r al Patho l og y

A bronchopleural or bronchocutaneous fistula may have such a

low resistance to gas flow that most of t he tidal volume passes

through it, making it impossible to adequately ventilate the other

lung (12,13,14). Large cysts or bullae may rupture under positive

pressure, making it mandatory that they be excluded from

ventilation. Another indication for lung separation is when lungs

have markedly different compliance or airway resistance such as

that which occurs following single-lung transplantation or

unilateral injury (15).


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The best method of producing lung isolation in a given situation

will depend on several factors, including the indication for lung

isolation, patient variables, available equipment, and the skill and

training of the anesthesia provider.

Anatomical Considerations

The right mainstem bronchus is shorter, straighter, and has a

larger diameter than the left. It takes off from the tr achea at an

angle of 25 degrees in adults. The left mainstem bronchusdiverges from the median plane at a 45-degree angle. These

angles are slightly larger in children (16). The right upper lobe

bronchus takeoff is very close to the origin of the right mainstem

bronchus. These anatomical features mean that it is usually

easier to intubate the right mainstem bronchus than the left, but it

is more difficult to place a tube in the right mainstem bronchus

without obstructing the upper lobe orifice.

Double-lumen Tubes

The double-lumen tube (DLT, DLET) is the device most

commonly used to provide lung isolation.

Desc r i p t i o n

A DLT is essentially two single- lumen tubes bonded together and

designated either as right- or left-sided, depending on which

mainstem bronchus the tube is designed to fit. The tracheal

lumen is designed to terminate above the carina. The distal

portion of the bronchial lumen is angled to fit into the appropriate

mainstem bronchus.


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The internal lumen of each tube is D-shaped with the straight

side of the D in the middle of the tube. The resistance of each

lumen of a 35 to 41 French (Fr) DLT has been found to be

comparable to the resistance of a size 6 to 7 mm internal

diameter single-lumen tracheal tube (17).

The bronchial cuff for right-sided tubes varies in shape,

depending on the manufacturer. On some tubes, the cuff has a

slot to allow ventilation of the right upper lobe. Some right-sided

DLTs have two bronchial cuffs with an opening for the right upper

lobe between them. The resting volume and compliance of

bronchial cuffs varies between different sizes and brands of DLTs

(18,19). Most manufacturers color the bronchial cuff blue. They

also use blue markings on the pilot balloon and/or the inflation

device for the bronchial cuff.

A few DLTs have a carinal hook to aid in proper placeme nt andminimize tube movement after placement. Potential problems

with carinal hooks include increased difficulty during intubation,

trauma to the airway, malposition of the tube because of the

hook, and interference with bronchial closure during

pneumonectomy. The hook can break off and become lost in the

bronchial tree.

Most manufacturers place a radiopaque marker at the bottom of

the tracheal cuff or at the end of the tracheal lumen. Other marks

may be placed above and/or below the bronchial cuff. Some have

a radiopaque line running the length of the tube.

Disposable DLTs are supplied in sterile packages, which include

a stylet, connectors, and suction catheter(s). A means to supply


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continuous positive airway pressure (CPAP) may be included with

the tube or can be purchased separately.

The connector (20) allows both lumens to attach to a breathing

system at the same time.

S iz i ng

Adult DLTs commonly come in sizes 35, 37, 39, and 41 Fr. The

French scale is the ex ternal diameter of the tracheal segment

times three. Some manufacturers also provide 26, 28, and 32 Frtubes for younger patients. Unfortunately, the French gauge

markings are of limited value in determining the most important

measurement-the diameter of the bronchial segment.

There are major variations between manufacturers in the

dimensions of the bronchial segment of DLTs of the same

nominal size and even among tubes of the

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same size from the same manufacturer (21,22,23,24). An

International Technical Specification has recommended that

outside circumference of the bronchial segment be designated in

millimeters (25). The diameter of the bronchial segment with the

cuff inflated may not increase with tube size (26).

Marg i n o f Sa fet y

The margin of safety for a DLT is the length of the

tracheobronchial tree between the most distal and proximal

acceptable positions (27,28). The margin of safety will depend on

the length of the lumen into which the cuff is placed and the


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length of the cuff. If the cuff is short or the mainstem bronchus

long, the margin of safety will be greater.

Left-sided Tubes

The outermost acceptable position for a left-sided DLT is when

the bronchial cuff is just below the carina. If the tube were more

proximal, the bronchial cuff could obstruct the trachea and/or the

contralateral (right) mainstem bronchus. In this case, the seal

between the two lungs would be lost. The most acceptable distal

position is when the the bronchial segment tip is at the proximal

edge of the upper lobe bronchial orifice. More distal insertion

would result in obstruction of the upper lobe bronchus.

The average length of the left bronchus from the carina to the

takeoff of the upper lobe bronchus is 5.6 cm. This leaves a

relatively small margin for placement, as there could be up to 3.5

cm of movement with neck flexion and extension (29). There is

great variability in the length of the bronchial segment of left-

sided DLTs currently available (30).

Right-sided Tubes

The margin of safety is defined differently for right-sided tubes. A

right-sided DLT is acceptably positioned if the right upper lobe

ventilation opening or the space between the two cuffs is aligned

with the right upper lobe orifice. Thus, the margin of safety is the

length of the ventilation opening minus the diameter of the

orifice. The margin of safety for right-sided tubes is considerably

less than for left-sided tubes.

Spec i f i c Tub es


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Carlens Double-lumen Tube

The Carlens DLT (Figs. 20.1, 20.2) is intended to be inserted into

the left mainstem bronchus. It has a carinal hook (spur). This

tube may be especially useful with massive hemoptysis when

verification of tube placement is especially difficult (31).

View Figure

Figure 20.1Carlens double-lumen tube. A:Theconnector has ports for fiberscope insertion or suctioning

and areas where a clamp can be applied to occlude gas

flow. B:Note the carinal hook and the blue bronchialcuff.

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View Figure

Figure 20.2Carlens tube in place.

White Double-lumen TubeThe White DLT (Fig. 20.3) is designed to fit the right mainstem

bronchus. It has a carinal hook. The cuff for the right mainstem

bronchus is circumferential superior to the o pening to the upper

lobe bronchus and continues distally behind the opening.

Robertshaw Right Double-lumen Tube

The bronchial portion of the Robertshaw right DLT (Fig. 20.4) is

angled at 20 degrees (32). The bronchial cuff has a slotted

opening in its lateral aspect (Fig. 20.5). The bronchial cuff is

proximal to the slot on the lateral surface and extends

tangentially toward the medial surface.

Robertshaw Left Double-lumen Tube


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The Robertshaw left DLT is shown in Figures 20.6and 20.7. The

angle of the bronchial portion is 40 degrees (32). The average

length of the bronchial segment is 23 mm for sizes 35/37 and 25

mm for sizes 39/41 (30).

Broncho-Cath Right-sided Tube

The Broncho-Cath right-sided tube has a bronchial cuff that is

roughly the shape of an S, or slanted doughnut. The cuff edge

nearest the right upper lobe bronchus is closer to the trachea

than the part of the cuff touching the medial bronchial wall ( Figs.

20.8, 20.9). A s lot in the tube just beyond the cuff corresponds to

the opening of the upper lobe bronchus (27). The end of the

bronchial segment has no bevel (33).

The shape of t he right bronchial cuff allows the venti lation slot to

ride off the right upper lobe orifice, increasing the margin of

safety. One study found that when this tube was inserted blindly,

right upper lobe obstruction occurred in 89% of cases (34).

Placement using fiberoptic endoscopy resulted in much better

positioning (35).


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View Figure

Figure 20.3White double-lumen tube. (Picture courtesy

of Teleflex Medical.)

Broncho-Cath Left-sided TubeOn the Broncho-Cath left-sided DLT (Fig. 20.10), the bronchial

portion of the tube is at an angle of approximately 45 degrees

(33,36,37). The bronchial portion has a curved tip. The bevel was

removed in 1994 but reintroduced in 2001 (33,38). The average

length of the bronchial segment is 30 to 31 mm (30). The tube is

available with or without a carinal hook.

Sher-I-Bronch Right-sided Double-lumen

Tube

The Sher-I-Bronch right-sided DLT has two cuffs on the bronchial

segment, one proximal and one distal to the upper lobe


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ventilation slot. The slot is 13 to 14 mm long (Figs. 20.11, 20.12).

One study found that poor lung isolation was more common when

this tube was used (39). A case has been reported in which the

tube tip became trapped in the right upper lobe bronchus (40).

View Figure

Figure 20.4Robertshaw right double-lumen tube inplace.

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View Figure

Figure 20.5Robertshaw right double-lumen tube in

place.

Sher-I-Bronch Left-sided Double-lumen TubeThe bronchial segment of the Sher-I-Bronch left-sided DLT

diverges from the main tube at an angle of 34 degrees. The

average length of the bronchial segment is 35 mm (30). The

bronchial segment has a bevel (30). One study found that the

bronchial cuff on this tube required significantly higher pressures

to achieve one-lung isolation than cuffs on other DLTs (41).

Silbroncho Double-lumen Tube

The Silbroncho DLT (Fig. 20.13) is made of si l icone, which is

softer than polyvinylchloride (PVC). The tube does not contain

latex. The bronchial segment is wire-reinforced distal to the

tracheal cuff. This allows it to be flexible and prevents kinking.


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The wire reinforcement also makes tube position easy to

determine on x-ray. The bronchial cuff is small and near the end

of the tube. It is available in sizes 33, 35, 37, and 39 Fr.

View Figure

Figure 20.6Robertshaw left double-lumen tube.(Courtesy of Rusch, Inc.)


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View Figure

Figure 20.7Robertshaw left double-lumen tube.

Techn i ques

Tube Choice

R i gh t ve r su s Le f t

When surgery is performed on the right lung, a left-sided DLT

should be used (42,43,44). Because the margin of safety in

positioning a right-sided DLT is so small, some prefer to use aleft-sided DLT whenever possible for left lung surgery (28,45).

During left pneumonectomy, immediately before the left mainstem

bronchus is clamped, the DLT can be pulled from the bronchus

and used for ventilating the right lung. A disadvantage of this

technique is the risk of blood and secretions moving from the


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operative (left) bronchus to the nonoperative bronchus. Other

possible problems include the tube becoming dislodged or

sutured in place during surgery. A ball-valve obstruction may

occur as a result of secretions or mediastinal pressure pushing

the tracheal lumen against the tracheal wall ( 46). A left DLT ma y

not provide optimum conditions for ventilating the residual lung

after left upper lobectomy (47).

A r ight-sided DLT should be used when i t is important to avoid

manipulation/intubation of the left main bronchus (e.g., an

exophytic lesion), when the left main bronchus is narrowed or the

left mainstem bronchus is so cephalad that the bronchial lumen

will not enter the

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left mainstem bronchus, left pneumonectomy, left lungtransplantation, left mainstem bronchus stent in place or when

there is tracheobronchial disruption on the left (43,48,49,50,51).


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View Figure

Figure 20.8Broncho-Cath right double-lumen tube.

Newer versions have no bevel at the end of the bronchialsegment. (Courtesy of Mallinckrodt Medical, Inc.)

Before placing a right DLT, the patient's chest x-ray or computedtomography scan can be closely examined to id entify a right

upper lobe bronchus takeoff, which would make it difficult to use

a right DLT. A left DLT should be placed in the right mainstem

bronchus in Kartagener's syndrome, which includes complete

situs inversus and a longer-than-normal right mainstem bronchus

(52).


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View Figure

Figure 20.9Broncho-Cath right double-lumen tube. The

bronchial cuff has the shape of an S or a slanteddoughnut, with the edge of the cuff nearest the rightupper lobe bronchus closer to the trachea than the part ofthe cuff touching the medial bronchial wall. A slot in thetube beyond the cuff corresponds to the opening of theright upper lobe bronchus. Newer versions have no bevelon the bronchial segment.

Size

Selecting an appropriately sized DLT for a given patient is critical

to minimize the frequency of complications (53).

A DLT that is too small may fai l to provide lung isolation or may

require bronchial cuff volumes and pressures that could produce

mucosal ischemia or bronchial rupture. Using too small a DLT

can result in the tube advancing too far into the bronchus, a

higher level of autoPEEP (positive end-expiratory pressure), or

barotrauma (54,55). An undersized tube may be more likely to be

displaced. Ventilation and suctioning are more difficult with a

small tube.


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Using a large DLT wil l result in less resistance to gas flow,

facilitate suctioning and passage of a fiberscope, and reduce the

risk of advancing the DLT too far into t he bronchus but may

result in trauma (56). Inability to insert a larger tube through the

larynx or past the carina or intrinsic or extrinsic obstruction in the

mainstem bronchus to be intubated may necessitate use of a

smaller tube.

A tube is oversized if the bronchial lumen wi l l not fi t into the

bronchus or there is no air leak with the bronchial cuff deflated

(22,38,57,58,59,60). It is too small if the bronchial cuff inflation

volume is greater than the resting cuff volume. Not more than 3

cc of air in the bronchial cuff should be required to create a seal.

When there is a high risk that f luids wil l seep past the bronchial

cuff, a smaller DLT should be used (61).

In adults, the dimensions of the cricoid ring best define those ofthe main bronchi (23). In children, age but

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not weight is a predictor of bronchial diameter, and the right main

bronchial diameter is significantly larger than the left ( 62).

Suggested sizes for DLTs in children are shown in Table 20.1.

Tubes from different manufacturers vary in size and may not fit

this table.


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View Figure

Figure 20.10Broncho-Cath left double-lumen tube.

(Courtesy of Mallinckrodt Medical, Inc.)


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View Figure

Figure 20.11Sher-I-Bronch double-lumen tubes. A:

Left-sided tube (top). Right-sided tube (bottom). B:Close-up of right bronchial segment, showing opening tothe right upper lobe. (Courtesy of Sheridan, Inc.)


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Age (years) Doubl -lumen Tube (French)

8 to 10 26

10 to 12 26 to 28

12 to 14 32

14 to 16 35

From Hammer GB, Fitzmaurice BG, Brodsky JB. Methods for single-lungventilation in pediatric patients. Anesth Analg 1999;89:14261429.

The size of the mainstem bronchus may be determined by

measuring the width of the patient's bronchus from a chest x-ray

or computed tomographic scan (22,54,60,63,64,65,66,67,68).

Unfortunately, it is not possible to accurately measure bronchial

width on many chest x- rays, and the correlation between the

tracheal and bronchial size may not be reliable enough to

determine the proper size DLT from the size of the trachea(56,59,63,69,70,71,72). Reliability may be increased by

measuring the tracheal diameter both anteropostally and

mediolaterally (73). The lung transplant patient may have a

significantly different sized bronchus than would have been

predicted from the size of the trachea (56).


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Preparing the Double-lumen Tube

The tracheal and bronchial cuffs should be inflated and checked

for leaks and symmetrical cuff inflation, making certain that each

inflation tube is associated with the proper cuff. The cuffs and

stylet should be lubricated with a water-soluble lubricant and the

stylet placed

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inside the bronchial lumen, making certain that it does not extend

beyond the tip. The connector should be assembled so that it can

be quickly fitted to the tube and breathing system after

intubation.

View Figure

Figure 20.13A:The Silbroncho double-lumen tube. B:The bronchial segment is wire-reinforced distal to thetracheal cuff.


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Insertion

The DLT is advanced through the larynx with the angled tip

directed anteriorly. After the bronchial cuff has passed the cords,

the tube is turned 90 degrees so that the bronchial portion points

toward the appropriate bronchus. If the tube is to be placed in the

left mainstem bronchus, the head and neck should be rotated to

the right before rotating and advancing the tube (74). Leaving the

stylet in place for the entire intubation procedure rather than

removing it once the bronchial cuff has passed the vocal cords

may result in more rapid and accurate placement ( 75). However,

some recommend that the stylet be removed just after the tube

passes the vocal cords to prevent trauma (76).

A DLT is most accurately placed by inserting a fiberscope into

the bronchial lumen and directing it into the appropriate bronchus

under direct vision (77,78,79,80,81,82). Concurrent direct

laryngoscopy may be required to elevate the supraglottic tissues

to facilitate passing the DLT through the glottic opening after the

fiberscope is in the trachea (83). This ensures that the correct

bronchus is intubated on the first attempt and avoids inserting

the tube too deeply or the tube becoming kinked in the upper

lobe bronchus (40).

A DLT wi th a carinal hook should be inserted with the bronchial

segment concave anteriorly until the bronchial cuff passes the

cords. It should then be rotated 180 degrees so that the hook is

anterior and advanced until the hook passes the vocal cords. The

tube is then advanced until the hook engages the carina. The


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hook can be tied closely to the tube with a slip knot to facilitate

passage through the larynx and then untied.

Inserting the bronchial portion into the bronchus can be

performed blindly after insertion through the vocal cords. In some

cases (e.g., bronchorrhea, bleeding), blind placement may

succeed where the fiberoptic technique does not (79).

With blind insertion, the correct depth of insertion may be difficult

to determine. However, this method may be useful where rapid

lung isolation or collapse is necessary. In adults, there is a

correlation between the ideal depth of insertion of left DLTs and

patient height but not weight or age (24,84,85,86,87). The ideal

depth of insertion can be estimated from the chest x-ray

(84,85,86). Advancing the tube with the bronchial cuff partially

inflated unti l an increase in resistance is felt (or only one side of

the chest moves and compliance is reduced) may preventinserting the tube too deeply (88,89,90,91). The bronchial cuff is

then deflated and the tube advanced a distance equal to the

length of the bronchial cuff plus 1 to 1.5 cm to place it just

beyond the carina (92,93). Depth of insertion may be estimated

by monitoring bronchial cuff pressure (94).

Since the tube usually moves upward with positioning, some

clinicians recommend that the tube should initially be inserted

more deeply than would be the ideal position (36,38,95,96).

Others believe that the danger of trauma is increased if the tube

is intentionally placed too deeply (97).

If the patient is anatomically difficult to intubate, a single-lumen

tracheal tube may be placed by any of the means that facilitate


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difficult intubations (98). An exchange catheter can then be

inserted into the single-lumen tube and the DLT inserted over the

catheter after the single-lumen tube has been withdrawn (99).

The WuScope (Chapter 1 8) has been successfully employed to

place a DLT in a patient who was difficult to intubate (100). A

DLT can be placed by using a lighted stylet (Chapter 19) in the

bronchial lumen (101) or a retrograde intubation technique (102).

Awake fiberoptic bronchial intubation with a DLT has been

reported (103). A DLT ma y be introduced over a gum elastic

bougie (45,104,105,106). It may be helpful to pass the bougie

through the opening for the right upper lobe orifice on right DLTs

(105).

A DLT may be inserted through a tracheostomy (107,108).

Cuff Inflation

Once the tip is thought to be in a mainstem bronchus, the

tracheal cuff should be inflated in a manner similar to that of a

tracheal tube (109,110). It is more difficult to inflate the bronchial

cuff correctly. An overinflated bronchial cuff is more likely to

herniate into the trachea, cause the carina to be pushed toward

the opposite side, or result in narrowing of the bronchial segment

lumen. Inflating the bronchial cuff beyond its resting volume may

result in dangerously high pressure (18,111).

The bronchial cuff should be inflated with small incremental

volumes until an airtight seal is just attained (109,112). The total

volume should be less than 3 mL (41). One technique is to

immerse the proximal tracheal lumen in water during ventilation


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via the bronchial lumen. The bronchial cuff is inflated until no

bubbles are seen escaping during positive-pressure inspiration

(110,111) (Fig. 20.14). Variations of this are to connect a balloon

(113) or a capnograph (111) to t he tracheal lumen. Another

method is to apply suction to the tracheal lumen (110). Absence

of bronchial seal will cause the reservoir bag in a breathing

system that is connected to the bronchial lumen to collapse.

Inflating the bronchial cuff to an airtight seal may not prevent the

spread of blood or secretions (61). The bronchial cuff may also

be inflated with water (114).

Confirming Position

Confirming proper tube position is essential because the tube

may not perform properly if incorrectly

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positioned. Position should be checked after insertion, after

repositioning the patient, and before beginning one-lung

ventilation, as these tubes often move during patient positioning

or surgical manipulations

(97,115,116,117,118,119,120,121,122,123). The most frequent

DLT movement is during lateral decubitus positioning. While

movement is usually outward, distal migration may also occur.

DLT position should be confirmed whenever there is evidence of

malfunction.


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View Figure

Figure 20.14Inflating the bronchial cuff. With the

tracheal cuff inflated, the bronchial cuff is slowly inflated.Right:A bronchial cuff leak is indicated by bubbles whenthe end of the tracheal lumen is placed under water. Left:With a seal, no bubbles appear.

Au s cu l t a t o r y Tech n i q u e s

Unfortunately, auscultation detects DLT malposition only part of

the time because breath sounds can be transmitted from one

region of the lung to adjacent areas (124,125,126,127). Studies

have shown that a significant percentage of DLTs thought to be

positioned satisfactorily by auscultation were found to be

inappropriately positioned on subsequent fiberoptic examination

(116,120,128). A DLT may function satisfactorily although not in

an ideal position. Another problem with auscultation is that once

the patient is prepped and draped, the chest is no longer

available for auscultation. One study found that auscultatory


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placement was not associated with an increased incidence of

complications during one-lung ventilation (39).

Clamping Method

Le f t -s i d ed Tubes

With only the tracheal cuff inflated and the tracheal lumen

connected to the breathing system, both lungs should be

auscultated in the axillary regions and upper lung fields to detect

differences. The bronchial cuff should then be inflated and bothlumens connected to th e breathing system. Auscultation should

then be repeated.

Next, the attachment between the breathing system and the

tracheal lumen should be occluded and the tracheal lumen

opened to atmosphere. Breath sounds should be heard only over

the left lung. If breath sounds are heard bilaterally, the tube is

too high in the trachea. Both cuffs should be deflated and the

tube advanced. If breath sounds are heard only over t he right

lung, the bronchial lumen is on the right side. If this is the case,

both cuffs should deflated, the tube withdrawn until its distal end

is above the carina, rotated, then reinserted. The steps outlined

should be repeated.

The attachment between the breathing system and the bronchial

lumen should then be clamped and the patient ventilated through

the tracheal lumen. The bronchial lumen should be opened to

atmosphere. Breath sounds should be heard only over the right

lung. If there is marked resistance to ventilation, the tube is

either too far into the left bronchus or is not deep enough. The


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position can be determined by deflating the bronchial cuff while

continuing to ventilate through the tracheal lumen with the

bronchial lumen clamped. If the tip is too deep in the left

bronchus, breath sounds will be heard only on the left side. If the

tube is not deep enough in the bronchus, breath sounds wil l be

present bilaterally. The tracheal cuff also should be deflated and,

depending on where breath sounds were heard, the tube pulled

back or advanced. Both cuffs should be reinflated and the

auscultatory sequence repeated.

R i gh t - s i d ed Tubes

Auscultation of a r ight-sided DLT is similar to that of a le f t-sided

tube. It is especially important to confirm ventilation of the right

upper lobe.

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Single Connector Method

An alternative technique is the single connector technique in

which a single connector is used to ventilate each lung in turn by

simply transferring the distal end of the DLT from one lumen to

the other, eliminating the need for repeated clamping and

unclamping (126). This has the advantage of being simpler and

requiring fewer steps and may result in reduced risk of creating a

potentially harmful ball-valve effect in a partially obstructed lobe

or lung by detecting it earlier.


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After the DLT is advanced to the desired depth, a single

connector from the breathing system is attached to the bronchial

lumen. While performing manual ventilation, the bronchial cuff is

inflated to create an airtight seal. Auscultation is used to confirm

that the intended lung is being ventilated. The connector is then

transferred from the bronchial lumen to the tracheal lumen. The

tracheal cuff is inflated to create an airtight seal, and it is

confirmed that the proper lung is ventilated. The connector is

then transferred to the bronchial lumen and short ventilations

performed while listening over the apex of the lung for vesicular

breath sounds. If these are not heard, the single connector is

detached from the bronchial lumen and a double connector is

connected to the two lumens.

F le x i b l e Endos co p i c Techn i q ue s

Flexible endoscopy is the most accurate method for determining

DLT position (120,129,130,131,132). Many recommend that this

should be the standard of care (81,131,133,134,135,136). Others

believe that the fiberoptic scope is helpful but not essential

(95,124,137,138,139). There is general agreement that fiberoptic

endoscopy is always needed for right-sided DLTs. Fiberoptic

methods to confirm the position of the DLT may not work in the

presence of blood or secretions (140). W henever there is any

doubt, this method should be used to check the position. A

further advantage is that it can be used to remove b lood or

secretions. It can also be used after the patient is prepped and

draped if a question arises with regard to proper tube placement.


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Left-sided Tubes

A f iberscope is placed in the tracheal lumen through the openend of the tube or through a port in the connector that is specially

designed for this purpose. As the fiberscope is advanced, the

carina should come into view. The top surface of the blue

bronchial cuff should be seen below the carina in the left

mainstem bronchus. The bronchial cuff should not herniate over

the carina, neither should the carina be pushed t o the right. An

unobstructed view of the nonintubated right mainstem bronchus

should be obtained.

The fiberscope should then be advanced through the bronchial

lumen to check for narrowing of the lumen at the level of the cuff

and an unobstructed view of the distal bronchial tree.

Right-sided Tubes

Looking down the tracheal lumen, the bronchial cuff's upper

surface should be seen below the carina in the right mainstem

bronchus. The fiberscope is then placed in the bronchial lumen.

The right middle lower lobe bronchial carina should be seen

below the end of the tube. The endoscopist should be able to

look into the right upper lobe orifice by flexing the tip of the

fiberscope superiorly.

B r o n c h o s p i r ome t r y

Pressure-volume and flow-volume loops are discussed in Chapter

23. Changes in compliance or resistance may mean that the DLT

is not correctly placed

(141,142,143,144,145,146,147,148,149,150). If a DLT is


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advanced into the trachea with the bronchial cuff partially

inflated, compliance is reduced when the tube impacts the

bronchus (92).

Ches t X -ray

Chest x-ray may be useful to confirm tube position when a

fiberscope is not available or cannot be used. However, it is less

precise than the fiberoptic bronchoscopy and is costly, time

consuming, and awkward to perform.

Stabilizing the Tube

Once correct tube position is confirmed, the tube should be

secured in place. Special fixation methods have been

recommended (151). During positioning, the tube should be held

at the level of the incisors and the head immobilized in a neutral

or slightly flexed position to prevent the tube from migrating into

an incorrect position.

Intraoperative Care

The bronchial cuff should be kept deflated (unless the lung needs

to be isolated to prevent spread of blood or infection) unti l the

lung needs to be collapsed to minimize damage to the bronchial

mucosa (38). Lung collapse will be most rapid if lung separationis initiated at end-expiration. Suction is of limited utility because

the gas trapped in the lung is distal to collapsible airways. If

despite best efforts complete lung separation cannot be

accomplished and gas is introduced into the ipsilateral lung with

each breath, then continuous suction may be helpful to evacuate


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the gas as it enters the lung (38). Bronchial cuff pressure should

be monitored and adjusted to the minimum necessary to achieve

an airtight seal.

A useful technique when the bronchial lumen is in the surgically

operated lung is to pass a suction catheter through the bronchial

lumen when the lung is deflated and to leave it until ready for

reinflation (152). This may prevent the bronchial lumen from

becoming obstructed by blood or mucus.

P.644

Replacing a Double-lumen Tube with a

Single-lumen Tube

If mechanical ventilation needs to be continued at the conclusion

of a case in which a DLT was used, it is usually desirable to

replace the DLT with a standard tracheal tube. Personnel who

are caring for the patient in the postoperative period are not

usually familiar with a DLT. After pneumonectomy, when all of the

patient's ventilation is conducted through one lumen of the DLT,

the small diameter of the lumen may make if difficult for the

patient to breathe spontaneously. W ith high minute venti lation,

this can lead to auto-PEEP (17). Pressure-support ventilation

(Chapter 12) can be used to decrease the imposed work of

breathing during spontaneous ventilation if replacing the DLT

cannot be performed. Suctioning through a DLT is difficult.


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In most cases, the procedure is simply to remove the DLT and

insert a single-lumen tube in its place. If the patient was difficult

to intubate or circumstances make visualizing the larynx difficult,

other techniques should be considered. One technique would be

to insert an airway exchange catheter into the tracheal lumen

before the DLT is removed. Special extra-long exchange

catheters are needed for the exchange. After the DLT has been

removed, the single-lumen tube is then advanced over the

catheter (153,154). Oxygen insufflation via the catheter will

reduce the incidence of hypoxemia.

Another technique has been described (155). At the conclusion of

the case, both cuffs are deflated and the DLT withdrawn until the

bronchial lumen is above the carina. The bronchial cuff is then

inflated and the lungs ventilated through the bronchial lumen.

The tracheal lumen is clamped, and an opening is created in thewall of the tracheal lumen. A single-lumen tube is then slipped

over a fiberscope, and the fiberscope is advanced through the

hole in the tracheal lumen and into the trachea. The opening in

the DLT is extended, and the DLT is slowly removed. The

fiberscope is then removed.

Hazards A sso c i a t ed w i t h Dou b le -l um en

Tubes

Many of the hazards associated with single-lumen tracheal tubes

(Chapter 19) can also occur with DLTs.

Difficulty with Insertion and Positioning


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Inserting a DLT may be time consuming. W hen there is severe

hemorrhage, this can be a major problem. Multiple insertions and

repositionings increase the risk of trauma. While they are very

useful in adults and older children, they are of ten too large for

small children. They are often difficult to position and usually

must be replaced with a single-lumen tube at the end of surgery.

The rigidity and width of the DLT can make intubation

complicated. The tube does not allow preshaping before

intubation, and the large width makes it difficult to pass the DLT

through a tracheostomy stoma, small airway, or nasal passage.

Tube Malposition

Certain physical conditions may make it difficult or impossible for

a DLT to be correctly placed (156,157). Preoperative fiberoptic

endoscopy may detect many of these problems. Even if a correct

position is achieved initially, head movement, a change in body

positioning, or surgical manipulation may result in t ube

malposition. Displacement during positioning can be decreased

by using a neck brace (123,158). Malpositioning is increased

when anesthesia providers have limited experience in lung

isolation (159).

If DLT malposition is suspected, fiberoptic techniques are clearly

advantageous in defining the problem and afford a means of

visual correction. While some have reported that monitoring

carbon dioxide waveforms helps to detect DLT displacement

(160,161), capnography does not reliably indicate DLT

misplacement (142,148,149,162).


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Consequence s

Functional indications of misplacement include the following:

Unsatisfactory Lung Collapse

An obstruction in the unventi lated lumen can prevent the

unventilated lung from deflating. If the lung cannot be collapsed,

operating time will be increased, and the surgical result may be

compromised. Another cause may be a tumor fragment in the

airway (163).

Obstruction to Lung Inflation

If the bronchial cuff is not below the carina, it may obstruct the

trachea and right mainstem bronchus. With right-sided tubes,

misalignment of the port for the right upper lobe can result in

obstruction. If the bronchial cuff on a left-sided DLT is too deep,

it may obstruct the upper lobe bronchus.

Gas Trapping

Gas trapping or expiratory obstruction may be the result of a one-

way valve effect that allows inflation but not deflation. If

unrecognized, it can result in cardiorespiratory embarrassment

and/or lung parenchymal damage.

Failure of Lung SeparationIf the airway to a bronchopleural fistula cannot be isolated from

that to the normal lung, barotrauma may develop with positive-

pressure ventilation, or the air leak through the fistula may be so

large that ventilation of the normal lung is compromised. An


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incompletely protected dependent lung may be flooded with blood

or secretions.

Poss i b l e Mal p o s i t i o n s

Bronchial Lumen in the Wrong Mainstem

Bronchus

In some cases, the bronchial portion will enter the opposite

P.645

lung. This is usually easy to detect and correct by using

fiberoptic endoscopy (115). In some cases, it may be best to

leave the bronchial lumen in the operative bronchus and isolate

the operative lung by clamping the bronchial limb and using the

tracheal lumen for ventilation (118,122). This may be appropriate

for right lung surgery but not for surgery on the left lung, sincethe right upper lobe bronchus would almost certainly be

occluded. An alternative option is to withdraw the tube until it is

intratracheal and to use a bronchial blocker (see below) to block

the operative lung.

It may be possible for the surgeon to assist in correctly placing

the tube once the chest is open (164). If it is determined that the

tube is in the wrong bronchus, both cuffs are deflated, and the

tube is withdrawn into the trachea. The surgeon then compresses

the bronchus, and the anesthesia provider advances the tube into

the correct side with surgical guidance. The cuffs are then

reinflated.


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Bronchial Portion Inserted too Far into the

Appropriate BronchusIf a left-sided DLT is inserted too deeply, the problem may be

that the tube is too small (156,165,166,167). It will result in

obstruction of the upper lobe. In some patients, a left-sided DLT

placed so that the bronchial cuff is just distal to the carina still

may cause left upper lobe obstruction. A high peak airway

pressure during one-lung venti lation should suggest t hismalposition (135).

Tube too Proximal in the Airway

If the tube is not sufficiently advanced into the bronchus, the

bronchial cuff may protrude into the trachea. The need to inject

more than 3 mL of air into the bronchial cuff to achieve a seal

should alert the user that the tube may be malpositioned. Thebronchial segment may slip out of its bronchus, especially during

changes in the patient's position. In many cases, no untoward

sequelae will occur. However, there may be obstruction of gas

flow to the other lung and inability to isolate the surgical lung.

Tip of Bronchial Lumen above the Carina

The tip of the bronchial lumen may be above the carina becauseof a tracheal lesion that prevents the tube from being advanced

farther. With this malposition, there will be unsatisfactory lung

deflation and failure of lung separation.

Incorrect Placement with Respect to the Upper

Lobe Bronchus


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oxygen source at ambient pressure to the opening to the

nonventi lated lung may h elp to prevent hypoxia

(175,176,177,178). This may also enhance collapse of the

nonventilated lung.

If hypoxemia is a problem despite proper tube position, CPAP

can be applied to the nondependent lung (179). Some DLT

manufacturers include a CPAP device with each DLT, or they

may be purchased separately (Fig. 20.15). Other measures to

improve oxygenation include dependent lung PEEP, occasional

ventilation of the nondependent lung (one breath every 5 to 10

minutes), insufflation of 2 to 3 L/minute of oxygen to the

nonventilated lung, and clamping of the pulmonary artery before

clamping the bronchus. Jet venti lation of the nondependent lobes

that are not being removed by using an airway exchange catheter

may be used to improve oxygenation (180).

Obstructed Ventilation

Many cases of obstruction are the result of a malpositioned tube.

In addition, inflating the bronchial cuff can cause narrowing of the

bronchial lumen (129,156) or may cause the carina to be

displaced laterally, producing obstruction of the other mainstem

bronchus (181). A defective tube or connector may c ause

obstruction (182,183).

Other causes of bronchial obstruction have been reported. In one

case, the bronchial cuff was left deflated until one-lung

ventilation was to begin, and necrotic tumor migrated into the

bronchus of the dependent lung, causing obstruction when one-


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lung ventilation was begun (184). The bronchial lumen can

become twisted (185). A carinal hook may obstruct the opening of

the tracheal lumen (186).

P.646

View Figure

Figure 20.15Device for applying continuous positiveairway pressure to a nonventilated lung. The adjustablevalve supplies pressures from 1 to 10 cm H2O.

A rela tive contraindication to using a DLT is a lesion (airwaynarrowing or endoluminal tumor) somewhere along the pathway

where the tube will reside. An aberrant tracheal bronchus may be

a contraindication for using a DLT (172,173).

Trauma


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Trauma to the r espiratory tract can occur whenever intubation

with a DLT is performed (187,188). Tears in the trachea and

mainstem bronchus have been reported

(76,187,188,189,190,191,192,193,194,195,196,197,198,199,200,

201,202,203).

Tube size is a factor. Large tubes have been involved more often

in injury than smaller ones (188). A tube that is too small and

requires excessive cuff inflation may cause ischemic injury. In

one reported case, an endobronchial polyp that developed at the

bronchial cuff site ended in a fatal hemorrhage (204).

Measures to reduce airway trauma include removing the stylet

after the tip of the tube has passed the vocal cords, avoiding cuff

overinflation, deflating the tracheal and bronchial cuffs when

repositioning the patient or the tube, and not advancing the tube

when resistance is encountered. Some bronchial cuffs canprovide one-lung isolation with significantly lower pressures than

others (41). It has been recommended that the bronchial cuff be

kept deflated until needed to minimize pressure on the bronchial

mucosa. This may not be prudent if there is a bronchial tumor, as

necrotic tumor may migrate into the other lung (184).

Tube ProblemsReported problems with DLTs include mislabeling, tracheal lumen

distortion that prevented a suction catheter from passing, a slit in

the septum, a defect that made the bronchial lumen kink on itself,

a split in the tubing to the bronchial cuff, a kink in the inflating

tube to the tracheal cuff, a protuberance in the wall of the tube


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with resultant tracheal lumen obstruction, and foreign bodies in

the DLT (205,206,207,208,209,210,211,212). The carinal hook

may bend backward, obstructing the opening of t he tracheal

lumen (213).

Tracheal or bronchial cuff rupture can occur. This most commonly

results from contact between the tube and the teeth or

laryngoscope during insertion. Proposed methods to avoid this

problem include the use of a retractable protective sheath (214),

a lubricated Penrose drain (215), and lubricated teeth guards

(216) and increasing the curve of the bronchial portion of the DLT

with the stylet (217). Another possible cause of cuff rupture is

movement during repositioning (218).

Surgical Complications

The bronchial cuff may be punctured by the surgeon ( 219,220). A

suture or staple may be placed through the DLT, or the surgical

procedure may result in a tight stenosis, which could entrap the

bronchial segment (221).

Failure to Seal

One of the reasons to use a DLT is to prevent material from

passing from one lung to the other during the surgical procedure.

Failure to prevent fluids from traversing the bronchial cuff could

result from malposition or from improper cuff inflation. Neither an

airtight bronchial seal nor a cuff pressure of 25 cm H 2O

guarantees protection against aspiration (61). Lubricating the cuff

with a gel will reduce the risk that fluid will leak past the cuff

(222,223).


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Difficult Extubation

Difficulty in removing a DLT may be due to anatomical

abnormalities, surgical fixation, or entanglement by other surgical

or anesthetic hardware (220,224).

P.647

Single-lumen Bronchial TubesAnother option for achieving lung separation is to use a single-

lumen tube to intubate a mainstem bronchus. Two bronchial

tubes may be used in situations where dual lung ventilation is

needed but circumstances bode against having one tube in the

trachea (225,226,227).

Single-lumen bronchial tubes are sometimes used in pediatricpatients whose airways are too small for DLTs or in whom a

bronchial blocker cannot be used

(1,165,226,228,229,230,231,232,233,234,235,236,237). In the

patient with massive hemoptysis, bronchial intubation with a

single-lumen tube is often the easiest and quickest method of

separating the lungs (5,10).

Equ i pmen t

Bronchial intubation is most often carried out with a conventional

tracheal tube. A cuffed tube will prevent re-expansion of the

collapsed lung. The distance from the tip of the tube to the

cephalad edge of the cuff must be shorter than the length of the


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mainstem bronchus to ensure that the cuff can lie entirely inside

the bronchus and the upper lobe bronchus is not obstructed

(238).

Special tubes with a single lumen, an angulated distal (bronchial)

tip, and cuffs at both the tracheal and bronchial positions are

available (239,240). They are longer than conventional single-

lumen tracheal tubes.

Techn i ques

Before insertion, the correct length and size of the tube should

be estimated from a chest x-ray or computed tomography (CT)

scan (238). If the nasotracheal route is used, most conventional

single-lumen tubes will not be long enough to provide a reliable

mainstem intubation. It is recommended that the tube should be

one half to one size smaller than the usual size selected for

tracheal intubation (237). For bronchial intubation in children, a

tracheal tube 0.5 to 2.0 mm smaller than recommended for the

particular patient should be used (229,231).

Right-sided intubation can usually be performed blindly, but the

tube is more reliably placed by using a bronchoscope. It may be

possible to align the Murphy eye with the right upper lobe

bronchus. It may be possible to rotate the tube so that the bevel

faces the upper lobe bronchial orifice.

Left mainstem intubation may be a chieved blindly by using a

stylet to curve the distal end of the tr acheal tube to the left (231)

but often requires bronchoscopic guidance. If blood or secretions

preclude fiberoptic visualization, fluoroscopy is another option.


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The chance of intubating the left bronchus will be increased if the

tube is rotated 180 degrees from its usual position before

advancing it beyond the vocal cords and the patient's head is

turned to the right (228,229,241,242,243).

A gum elastic bougie can be inserted into the chosen bronchus

by using a bronchoscope. The bronchial tube can then be

railroaded over the bougie into position (244).

Correct positioning can be confirmed by auscultation, x-rays,

and/or flexible bronchoscopy.

The tube should be withdrawn into the trachea when one-lung

ventilation is no longer needed.

Eva lua t i on

Advantages of using a single- lumen tube for lung separation

include simplicity and the rapidity with which lung separation can

often be achieved, particularly when the right lung must be

ventilated.

Disadvantages include frequent lack of ventilation of the right

upper lobe with right mainstem intubation (38,236). Left upper

lobe ventilation may also be excluded when the left mainstem

bronchus is relatively short (238). Neither suctioning nor

application of CPAP to the nonventilated lung is possible.

There may be failure to achieve an adequate seal, especially if

an uncuffed tracheal tube is used or if the cuff is not inside the

bronchus (226,236,238,245). Lung collapse will be incomplete,

and the healthy ventilated lung will not be protected from

contamination. Both lungs cannot be ventilated at the beginning


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of anesthesia, and the collapsed lung cannot be re-expanded and

ventilated until the tube is withdrawn into the trachea ( 236).

Bronchial-blocking Devices

Ind i ca t i ons and Use

Indications for bronchial blockers are similar to those for a DLT,

with the exception of independent lung ventilation (44,226,246).

They are often used in patients in whom using a DLT is not

possible or advisable (nasal intubation, small patient, difficult

intubation, patient with a tracheostomy, subglottic stenosis, thick

and excessive secretions, need for continued postoperative

intubation)

(240,247,248,249,250,251,252,253,254,255,256,257,258,259,260

,261). A blocker may be especially useful for providing lung

separation in a critically il l patient with a single-lumen trachealtube already in place. Another indication may be the patient on

anticoagulants, since placing a blocker is usually less traumatic

than inserting a DLT (8). A blocker may allow a larger fiberoptic

endoscope to be used and provide better suctioning than a DLT

(262). A modified bronchial blocker can be used for tracheal gas

insufflation to reduce carbon dioxide within the dead space by

delivering fresh gas near the end of the tracheal tube ( 263).

P.648

Another indication for a blocker is the need to block a segment of

a lung rather than the entire lung


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(9,14,258,259,264,265,266,267,268,269,270). This cannot be

done with a DLT. A blocker may be used to sequentially block

different parts of the lung (270).

A blocker may be used to achieve lung isolation in the patient

with an improperly positioned double-lumen or bronchial tube

(53,122,238,271,272,273). A blocker may be useful if both lungs

require sequential blockage (274). The blocker can be shifted to

the opposite lung when needed. If one blocker does not provide

complete one-lung isolation, a second blocker may be used

(173,275,276,277).

Finally, there is no need to change the tube at the end of the

operation if postoperative mechanical ventilation is needed if a

bronchial blocker is used.

Dev ices

Univent Bronchial-blocking Tube

Desc r i p t i o n

The Univent tube is a cuffed silicone tracheal tube with a small

additional internal lumen along its concave side

(7,11,226,236,278,279,280,281,282,283,284) (Figs. 20.16,

20.17). The s mall channel contains a movable tubular blockerthat has a blue high-pressure, low-volume cuff. The blocker can

be advanced sufficiently beyond the tip of the tube to block

airways smaller than a mainstem bronchus (246,260,264,265).


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View Figure

Figure 20.16Univent bronchial blocker. The cuffed

tracheal tube has a small lumen along its concave side,which contains a tubular cuffed bronchial blocker. The

blocker can be advanced into a mainstem bronchus orsmaller airway.

The blocker has external depth markings to help determine theblocker position in relation to the tube. There is a s light bend in

the blocker above the cuff. The blocker tip is radiopaque. A grip

allows the user to rotate the blocker. A locking clamp fixes its

depth below the tip of the tube.

As shown in Table 20.2, the Univent tube is available in several

sizes. It has a slightly larger-than-usual external diameter for its

internal diameter because of the space required by the blocker.

Univent tubes that are 5 mm and larger have a lumen that can be

used for suctioning, CPAP, or oxygen insufflation (285). Adult

versions of the Univent blocker are hollow.

The Univent blocker (Uniblocker) can be purchased separate

from the tracheal tube and used with other tracheal tubes


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coaxially or in parallel (265,286) (Fig. 20.18). It is supplied with a

swivel adaptor that fits onto the tracheal tube connector. This

adaptor allows connection to the breathing system and has a port

for a fiberoptic scope in addition to a port for the blocker.

Use

Before use, the bronchial blocker and tube cuffs should be

inflated and checked for leaks. Both the tube and the blocker

should be well lubricated. After the cuffs have been deflated, the

blocker should be pushed back and forth in the tube to ensure

free movement. The blocker should then be fully retracted into

the tube lumen and fixed in place by using the clamp.

If there is an unobstructed view of the larynx, the Univent tube is

inserted in the same way as a conventional tracheal tube. If the

patient has a difficult airway, it can be inserted over an airway

exchange catheter or other device (287). The blocker can be

extended and used as an introducer (288,289). After the blocker

has passed the vocal cords, the tube is t hreaded over it and into

place.

After the Univent tube is inserted, the tracheal tube cuff is

inflated, and the patient is ventilated. The blocker is visualized by

using a flexible fiberoptic endoscope through an airway adaptor

with a port for the scope and is maneuvered into the appropriate

bronchus. The blocker tip direction can be changed by twisting

the shaft (290). It may be useful to deflate the tracheal tube cuff

and rotate the tube so that the blocker is directed toward the side

to be occluded.


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A guide wire can be inserted through the blocker 's lumen and be

used to direct the blocker into place, especially when it is

necessary to block an airway smaller than a mainstem bronchus

(258).

Another method of placing the blocker in the r ight or le ft main

bronchus is to insert a fiberscope through the trachea tube into

the bronchus to be blocked and then to advance the tube into

that bronchus. The blocker is then advanced into the bronchus

and the tube withdrawn into the trachea, leaving the blocker in

the bronchus. This technique may result in trauma to the airway

(291).

P.649


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View Figure

Figure 20.17Univent bronchial-blocking tubes.

Top:The bronchial blocker is retracted. Bottom:The bronchial blocker is advanced, and the cuff isinflated. (Courtesy of Vitaid.)

TABLE 20.2 Univent Tubes


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I nternal Diameter

(millimeters)

Outer Diameter

(millimeters)a

Age (years)

3.5 (uncuffed) 7.5/8.0 6 to 10

4.5 8.5/9.0 10 to 14

6.0 9.7/11.0 14 to 16

6.5 10.2/12.0 16 to 18

7.0 11.6/12.5 Adult

7.5 11.2/13.0 Adult

8.0 11.7/13.5 Adult

8.0 12.2/14.0 Adult

9.0 12.7/14.5 Adult

a

Values are sagittal/transverse.From Hammer GB, Fitzmaurice BG, Brodsky JB.

Methods for single-lung ventilation in pediatricpatients. Anesth Analg 1999;89:14261429; Frolich


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MA. Postoperative atelectasis after one-lung ventilationwith a Univent tube in a child. J Clin Anesth2003;15:159163; Hammer GB, Brodsky JB, RedpathJH, et al. The Univent tube for single-lung ventilationin paediatric patients. Paed Anaesth 1998;8:5557;Tobias JD. Variations of one-lung ventilation. J ClinAnesth 2001;13:3539.

The bronchial blocker can be inserted blindly. The whole tube isturned so that its concavity faces the side to be blocked. The

blocker is advanced into the mainstem bronchus and the cuff

inflated. This method has not proved very successful and may be

associated with airway trauma (282,292).

The blocker position should be checked by using a fiberscope.

The cephalad tip of the bronchial cuff should be below the carina.

The blocker should then be fixed to the tracheal tube by using

the cap stopper and blocker grip.

When the bronchus needs to be blocked, the lung is deflated with

the blocker open to atmosphere. The bronchial blocker cuff

should be inflated by using the least amount of air that will

provide a seal. This can be achieved by attaching the sample l ine


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from a carbon dioxide analyzer to the proximal end of the blocker

and noting when the waveform disappears (293). Another method

is the bubble test, in which the end of the bronchial lumen is

placed into water in a beaker (294). When the bronchus is

sealed, no bubbles will be observed passing through the water.

The typical cuff inflation volume is 5 to 6 cc (112).

The blocker from a Univent tube can be removed from the tube

and inserted alongside a tracheal or tracheostomy tube

(265,295,296). The blocker is then

P.650

guided into place with a fiberscope inserted through the tube.

View Figure

Figure 20.18The Univent bronchial blocker can be

purchased separately from the tube. The connector has

ports for attachment to the tracheal tube and breathingsystem, for introducing the blocker, and for a fiberscope.

Note the cap that fits over the end of the blocker.


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When the blocker is no longer needed, the cuff is deflated and

withdrawn into the main tube. If the Univent is to be used for

postoperative ventilation, the blocker should be fully retracted

and disabled to avoid inappropriate use by caregivers who are

unfamiliar with the device (297).

Eva l ua t i o n

Most studies show that the Univent provides lung isolation

equivalent to that of a DLT (11,280,298,299,300,301).

The Univent may be easier to insert and position correctly than a

DLT and may be especially useful for the difficult-to-intubate

patient (287,288,289,302,303,304,305). It can be used in the

patient with a tracheostomy (254,253,296) and for nasal

intubation (247). It can be used for postoperative ventilation

without having to reintubate the patient.

It is possible to use suction, apply CPAP, or insufflate oxygen

through the blocker lumen (278,306). The blocker with the cuff

deflated has been used for jet ventilation during carinal resection

(307,308).

Reports of problems with the Univent include the cap becoming

dislodged from the tip of the blocker ( 309,310) and fragmentation

of the tube inner wall and connector (311,312).

The Univent's curved shape is fixed, and this may be a

disadvantage when sliding it over a bronchoscope. It will not

soften in a warm water bath (38). It may distort the neck anatomy

sufficiently to make internal jugular vein cannulation difficult

(313). Bronchial perforation by the blocker during blind insertion


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has been reported (292). A case has been reported of prolonged

postoperative atelectasis after using a Univent tube (262). It is

not recommended for use in children below the age of six years.

When comparing the Univent with a left DLT, there was a greater

incidence of malposition with the Univent (119), but comparison

of the Univent and a right DLT failed to demonstrate a clear

advantage (35). The Univent is more expensive than a DLT or

other blockers (79,119,310).

A disadvantage of the Univent tube is the large amount of cross-

sectional area occupied by the blocker channel, especially in the

smaller tubes (236). It is not available in a size that would fit an

infant or small child.

Another problem is that the small lumen is re la tively easily

blocked by blood or pus (285). As a result, blood or pus may

accumulate and contaminate the dependent lung when theblocker is deflated.

The blocker's low-volume, high pressure cuff may cause in

mucosal injury (314,315).

The larger external diameter may make it difficult to pass the

Univent between the vocal cords.

Arndt Bronchial BlockerDesc r i p t i o n

The Arndt bronchial blocker assembly (wire-guided bronchial

blocker, WEB, FWEB) is designed to be used for a patient with a

single-lumen tracheal tube already in place

(44,111,246,253,316,317,318,319,320,321,322,323). It consists


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of two parts: A blocking catheter and a special airway adaptor.

Either may be purchased and used separately.

Blocking Catheter

The Arndt blocking catheter (Fig. 20.19) has a low-pressure,

high-volume balloon that has either an elliptical or spherical

shape. The spherical balloon is relatively compliant unless

overinflated and takes an elliptical form when inflated in a small

bronchus. The 9 Fr catheter is available with an elliptical balloon

that provides a longer sealing profile. It is recommended that the

elliptical cuff be limited to left mainstem intubation (236,246).

P.651


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View Figure

Figure 20.19Arndt bronchial blocker with multiport

adaptor. The wire loop can be cinched around the tip ofthe fiberscope, or the fiberscope is passed through theloop. The adaptor has ports for attachment to the trachealtube and breathing system, for introducing the blocker,and for a fiberscope.

A f lexible nylon wire passes through the proximal end of thecatheter and extends to the distal end, then exits as a small loop

(Fig. 20.19). The size of the loop may be increased or decreased

by advancing or retracting the wire assembly.

There are three sizes: 9, 7, and 5 Fr. Characteristics of the

blockers are shown in Table 20.3. Near the distal end of the 9 Fr

catheter are side holes to facilitate lung deflation.

Airway Adaptor

The multiport adaptor (Fig. 20.19) allows simultaneous

introduction of a bronchoscope and the blocker while maintaining

mechanical ventilation. It has four ports:


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A 15-mm female connector that attaches to the tracheal

tube;

A side port wi th a 15-mm male connector that attaches to

the anesthesia breathing system;

A port angled approximately 30 degrees for the bronchial

blocker; and

A port for the f lexible endoscope.

The blocker port has a Tuohy-Borst type connector to maintain anairtight seal and lock the blocker in place (by tightening the

connector around the blocker) or to allow free movement of the

blocker (by loosening the connector). The bronchoscopy port has

a plastic sealing cap.

Use

Before use, the inside of the tracheal tube and the o utside of theblocker and the bronchoscope should be well lubricated with a

silicone spray. The loop should be adjusted so that it loosely

approximates the outside diameter of the bronchoscope. The

blocker balloon should be inflated to test for leaks and then fully

deflated.

For each size Web, there is a tracheal tube size for which coaxial

placement is limited by the diameters of the blocker and

fiberscope used during placement. When these limits are

exceeded, parallel placement may be required. Either t he web is

passed outside the tracheal tube with guide loop inoperable, or a

fiberscope is also placed in parallel with the tracheal tube before

or after intubation.


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TABLE 20.3 Arndt Endobronchial Blockers

Size(French)

Smallest Single-lumenTube In ternal Diameter

for Coaxial Use

(millimeters)

Length(centimeters)

Cuf f Shape Average Cuf fI nfl ation Volume

(cubic cent imeters)

9 7.5 78 and

65

Elliptical 6 to 12

Spherical 4 to 8

7 6.0 65 Spherical 2 to 6

5 4.5 65 and

50

Spherical 0.5 to 2.0

From Klafta JM. One-lung anesthesia; making it work (ASA Refresher Course#509). Park Ridge, IL: ASA, 2004.

P.652

The wire in the blocker lumen is used in either of two ways: (i)

when cinched tightly around the tip of the fiberscope, the

fiberscope carries the blocker into its desired location, and (i i)

when the fiberscope is passed through the loop, it provides a

track for blocker to pass through after the fiberscope is placed

into the bronchus.


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After the patient is intubated and venti lation has begun, the

multiport adaptor is connected between the breathing system and

the tracheal tube. The bronchoscope is advanced through the

guide loop. This allows the blocker to follow the bronchoscope.

Alternately , the wire loop may be placed over the end of the

blocker prior to attaching the airway adaptor to the tracheal tube

(324).

The bronchoscope is advanced into the airway to be blocked and

then the guide loop is slid over the end of the bronchoscope. The

bronchoscope is withdrawn slightly to visualize the blocker. The

blocker is then advanced or withdrawn into position (324,325). It

may be advisable to advance the blocker approximately 1 cm

beyond the optimal position when the patient is in the supine

position to avoid dislodging the blocker toward the trachea while

the patient's position is changed to the lateral decubitus position(246). The balloon is then inflated under direct vision. The

balloon should fil l the entire bronchial lumen and not herniate

into the trachea. Following placement, the balloon may be

deflated until one-lung ventilation is required.

Removing the wire loop will result in an open channel, which

allows CPAP application, oxygen insufflation, suctioning, or

intermittent inflation. Leaving the wire loop during the operation

might damage the airway and entails the risk that the loop may

accidentally be stapled into the bronchial closure (326). However,

leaving the loop in place allows the blocker to be repositioned

(327). It may be possible to reposition the blocker by using

fiberoptic endoscopy (326). Excessive force should not be used


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when removing the wire guide, because this may displace the

blocker.

Lung collapse can be expedited by attaching a syringe or

applying suction to the blocker channel (44,328). However, some

clinicians do not recommend using suction through this channel

because of the risk of developing negative pressure pulmonary

edema (326). When no longer needed, the blocker cuff should be

fully deflated and the blocker removed.

Eva l ua t i o n

The Arndt blocker system can be used in the patient who is

already intubated (316,317,329), in the patient with a

tracheostomy (318,324,325), or with a nasal intubation (253,318).

It has been used to provide single-lung ventilation in children as

young as 17 months (245). It may be especially useful for the

patient in whom a DLT would be difficult to use

(260,316,318,319,320,321,330). It has been used in a newborn

(322). It allows a larger internal cross-sectional area than a DLT

or Univent tube of similar outside diameter ( 331). It may require

fewer insertion attempts than a DLT (332). If the wire is removed,

the lumen can be used for suctioning or administering oxygen or

CPAP.

P r o b l ems

A disadvantage is that once the wi re loop is removed, it cannot

be reinserted through the channel to allow repositioning of the

blocker. Placement requires the availability of fiberoptic

equipment and someone able to use it. It takes longer to position


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and to achieve complete lung collapse compared with the Univent

tube or a DLT (328,332). The balloon may be sheared when it is

removed from the blocker port (333).

Cohen Tip-deflecting Bronchial Blocker

The Cohen tip-deflecting bronchial blocker (Fig. 20.20) has a 9 Fr

external diameter and a central lumen with a 1.6 mm diameter

(334). The high-volume, low-pressure blue balloon at the tip is

spherical in shape. The average inflation volume is 5 to 8 mL.

There are side holes between the tip and the balloon to evacuate

gas from the distal lung or to insufflate oxygen. A proximal

control wheel that can be operated with the thumb and forefinger

is used to adjust tip deflection (Fig. 20.21). The catheter has

depth markings and an indicator arrow that shows the direction in

which the tip deflects.


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View Figure

Figure 20.20Cohen tip-deflecting bronchial blocker. The

proximal control wheel is used to adjust tip deflection. Anarrow on the wheel indicates the direction to which the tipdeflects. (Courtesy of Cook Critical Care.)

P.653


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View Figure

Figure 20.21The tip of the Cohen bronchial blocker can

be manipulated to fit into either bronchus.

In most cases, the blocker and a fiberscope are inserted throughan appropriately sized tracheal tube. The blocker can also be

placed outside the tracheal tube and guided into place with a

bronchoscope placed through the tracheal tube.

A multiport airway adaptor li ke the Arndt is attached to the

breathing system end of the tracheal tube. Alternatively, a

standard swivel adaptor can be used for insertion.

An assistant with or without video f lexible fiberoptic scope may

be necessary because it may require two hands to manipulate the

blocker into position, one to deflect the tip and the other to rotate

and advance the catheter.

Embolectomy Catheter


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Desc r i p t i o n

An embolectomy (Fogarty) catheter can be used as a bronchial or

segmental blocker

(1,14,53,62,226,248,251,256,257,267,268,269,275,324,335,336,3

37,338,339,340,341,342,343,344). This catheter is readily

available in most operating suites where vascular surgery is

performed or can be purchased for this purpose. It comes with a

stylet in place so that it is possible to place a curvature in the

distal tip to facilitate guidance to the target bronchus. The

occlusion balloon has a high-pressure, low-volume cuff (246). It

comes in a variety of sizes. Adult bronchi can be blocked with 7

Fr catheters, whereas 2 Fr to 5 Fr catheters are suitable for

segmental or pediatric blockade.

Use

Prior to use, the blocker should be lubricated with jelly or silicone

spray to facilitate passage. The balloon should be tested for

leaks and then fully deflated. A catheter with a faulty or eccentric

balloon should be discarded.

The embolectomy catheter may be placed before or after

intubation with a single-lumen tracheal or tracheostomy tube and

can be passed either through or alongside the tube. Placing the

catheter alongside the tube allows the tube to splint the blocker

in position. An alternative method is to insert the catheter

through a hole made in the side of the tracheal tube (345).

If the patient is already intubated, the catheter containing a stylet

may be passed through a fiberoptic endoscope adaptor


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(335,341,342). This allows uninterrupted ventilation. The Arndt

multiport airway adaptor (previously mentioned) or similar device

(346) may also be used to prevent an air leak. An annular space

around the fiberoptic endoscope and embolectomy catheter

equivalent to a single-lumen tube with an inner diameter of 4 to 5

mm will be necessary to allow exhalation in a reasonable period

of time (347).

A f iberoptic endoscope is passed down the tracheal tube, and the

embolectomy catheter is guided into the appropriate bronchus

under direct vision. Twirl ing the catheter between the fingers at

the proximal end or rotating the tracheal tube will impart lateral

direction to the tip (98). Additional lateral direction may be

gained by rotating the tracheal tube to one side or the other.

After the tip is advanced into the proper position, the stylet is

removed, the catheter balloon is inflated under direct vision, andthen the fiberscope withdrawn.

A modification of this technique is to deliberately intubate a

mainstem bronchus with a tracheal tube one size smaller than

would be appropriate for the trachea, advance the blocker

through the tracheal tube, then withdraw the tracheal tube into

the trachea (348,349,350,351). It may be helpful to preshape the

tracheal tube by using a stylet (351). Once the catheter is in the

targeted bronchus, the stylet is removed. Removing the tracheal

tube followed by insertion of a larger tracheal tube beside the

Fogarty catheter will securely fix the catheter in place. The

catheter balloon is inflated slowly until no air enters the blocked

lung, as detected by using auscultation. The Fogarty catheter


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should be securely taped to the tracheal tube to prevent it from

being dislodged. A fiberoptic endoscope should be used to check

the position of the blocker. The catheter ballooon should be

deflated and the lung collapsed by using pressure on the chest

and/or suction through the tracheal tube (351). The catheter

balloon should then be reinflated to the same volume as

previously used.

Eva l ua t i o n

The use of an embolectomy catheter has many advantages. It

can be passed through a single-lumen tracheal tube in a n already

intubated patient, and there is no need for reintubation if

postoperative mechanical ventilation is needed. It may be useful

in

P.654

pediatric patients (62,236,267,268,324,337,338,340,345,352), the

patient with a tracheostomy (252,336,351,353), or for a nasal

intubation. The embolectomy catheter is less expensive than a

DLT, Univent tube, or Arndt blocker (326,339). Fogarty catheters

are relatively thinner for a given balloon volume when compared

with other bronchial blockers and thus will allow the use of larger

tracheal tubes, especially in pediatric patients when they are

placed side by side in the trachea (351).

P r o b l ems

A significant disadvantage is the lack of a hollow center.

Suctioning, oxygen insufflation, or applying CPAP to the blocked


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lung is not possible, and lung collapse takes longer and may not

be as complete as with a DLT or a blocker with a hollow lumen

(62). The obstructed lung segment cannot be re-expanded until

the blocker is removed. Another disadvantage is that it is made

of latex, so it cannot be used in the patient with potential latex

allergy (Chapter 15). Most of these devices have low-volume,

high-pressure cuffs and can damage the airway, although the

pressure may be less than that exerted by the cuff on a DLT

(109,236).

There are no reported complications with the embolectomy

catheter in adults (246). Bronchial rupture has been reported with

an overinflated balloon in a child (337).

Other

Balloon atrioseptostomy, Foley urinary, and Swan Ganz

pulmonary artery catheters have been used as bronchial

blockers. They have a central lumen for suction or administration

of oxygen to the blocked lung.

P rob l ems w i t h B r on ch i a l B l o c k er s

A blocker may not be suitable for the patient with a high r ight

upper lobe bronchus takeoff or a tracheal bronchus (173,354). It

may be necessary to either use a second blocker or a DLT under

these conditions. If the distance between the carina a nd the

tracheal bronchus is small, it may be possible to herniate the

balloon on the bronchial blocker so that it blocks the upper lobe

bronchus (355). It may be possible to use the tracheal cuff of the

Univent tube to block a tracheal bronchus (356).


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A blocker may be dislodged into the trachea (357). The inf lated

balloon may then block ventilation to both lungs, prevent collapse

of the operated lung, and/or ca use air trapping. Other

complications reported include fixation by surgical staples (358);

perforation of the blocker balloon by a surgical needle ( 359); and

accidental inflation of the blocker cuff when it was just below the

tip of the tube, resulting in obstruction to gas flow (360).

The narrow blocker lumen may result in ineffective removal of

secretions and pulmonary soiling after the cuff is deflated (361).

Lung deflation may not be as satisfactory or achieved as rapidly

with a bronchial blocker as with a DLT (332).

Development of severe hypoxemia has been reported after

continuous suctioning of the nondependent lung through a

bronchial blocker (362). If suction is used to facilitate lung

collapse, it should be applied for only a few seconds,intermittently and with low pressure (246).

References

1. Camci E, Tugrul M, Tugrul ST, et al. Techniques and

complications of one-lung ventilation in children with suppurative

lung disease: experience in 15 cases. J Cardiothorac Vasc

Anesth 2001;15:341345.

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occlusion of the right upper lobe bronchial orifice to tamponade

life-threatening hemoptysis. Anesthesiology 1995;82:1529

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thoracic anesthesia (ASA Refresher Course #175). Dallas, TX:

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5. Mangar D. Treatment of pulmonary artery haemorrhage with a

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9. Kabon B, Waltl B, Leitgeb J, et al. First experience with

fiberoptically directed wire-guided endobronchial blockade in a

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10. Klafta JM, Olson JP. Emergent lung separation for

management of pulmonary artery rupture. Anesthesiology

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11. Inoue H, Suzuki I, Mwasaki M, et al. Selective exclusion of

the injured lung. J Trauma 1993;34:496498.[CrossRef]

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12. McGuire GP. Lung ventilation and bronchopleural fistula. Can

J Anaesth 1996;43:12751276.

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13. Darwish RS, Gilbert TB, Fahy BG. Management of a

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14. Otruba Z, Oxorn D. Lobar bronchial blockade in

bronchopleural fistula. Can J Anaesth

Chapter 20. Lung Isolation Devices

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