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480 oracic ultrasound
RIGHT JUGULAR VEIN
Figure 37 – Transverse scan at the right base of the neck.
CAROTID A.
LARYNX
RIGHT INTERNAL JUGULAR VEIN
Figure 38 – Right internal jugular vein as seen by the operator located behind the patient.
CAROTID A.
Choice of vessel
In the literature, many types of access to large veins are outlined. Many are located in the neck
and in the upper limbs. More rarely in the groin. Each access has particular aspects related
to the complexity of execution or complications that may ensue. Most of these studies focus
on cannulations in surgical or intensive environments.
Emergency vascular accesses have never been compared to each other, or with a gold standard.
erefore they have traced the methods in use in other settings.
In our Operative Units the cannulation of the internal jugular vein has been practiced under
ultrasound guidance for many years (from 1998), as it is considered easier and with less risk
of complications. is approach has recently found important validations. Whenever possible, each central venous catheter should be placed under ultrasound guidance, or at least
after ultrasound assessment of the puncture site.
Interventional chest ultrasound 481
COLLARBONE
Fig. 39
Fig. 39
Fig. 40
SUBCLAVIAN VEIN
COLLARBONE
SUBCLAVIAN VEIN
SUBCLAVIAN VEIN
PLEURAL LINE
Fig. 41
Figures 39-41 – Series of scans along the course of the subclavian vein.
482 oracic ultrasound
However, the catheterization of the internal jugular vein has some drawbacks:
• Impractical management of the access site in the long term.
• Anatomical variability of the vessel.
• Variability of its relations with adjacent structures
89-92
.
Indeed, these drawbacks can increase the difficulty of catheterization, especially in patients
with bulky necks or inconspicuous skin landmarks.
It is clear, however, that ultrasound examination can help overcome these difficulties and the
internal jugular vein can be the preferred access way in emergency. Moreover, the ultrasound
guidance allows to prick the neck below the apex of the Sedillot’s triangle, in a lower and
more practical point compared to the classical method93.
As already mentioned above, internal jugular veins are asymmetric because of one’s dominance.
e differences can be significant and in high percentages the non-dominant one has a diam-
eter of about 0.4 cm. Pre-procedure echography or ultrasound-guided cannulation enable to
understand these differences and to minimize failures and complications.
Puncture of the vessel
Under ultrasound guidance, for physical principles, a needle is more visible if its route in the
tissues is coplanar with the ultrasound beam (in plane). In addition, a needle in plane with
the ultrasound beam is much more visible when specular. is means that it is brighter when
the insonation angle is closer to normality. ese assumptions that simplify the procedure
can not always be achieved.
e Sedillot’s triangle between the sternal and clavicular heads of the SCM, is the landmark
for the puncture of the internal jugular vein.
e echo-guided puncture of the internal jugular vein is carried out by positioning the probe
transversely to the vessel. e entry of the needle is in center of the largest side of the probe,
which in turn lies with its center on the lumen of the vessel (Fig. 42).
e introduction of a needle below the apex of the Sedillot’s triangle is easily detected by the
ultrasound probe, if it is placed transversely and parallel to the base of the triangle, below the
access point. e echoes of the tip can be tracked as they pass obliquely through the subcutaneous tissue until they reach the vessel. is approach is perpendicular to the scan plane
(out of plane), so the ultrasound beam must follow the tip of the needle and not statically
show its axis. is error may allow the tip to deepen and cause injury.
Figure 42 – Needle-probe coupling.
Interventional chest ultrasound 483
e needle follows first a subcutaneous route, then, when it appears as a point on the screen
under the probe and above the vessel, it is tilted at 45° or more to allow the vascular access
and the subsequent introduction of the metal guide.
Ultrasound guided internal jugular vein cannulation is a technically simple procedure, because the vessel is very superficial. erefore, the access is often immediate without the need
to see exactly the needle, provided that the alignment needle/probe and probe/vessel lumen
is perfect and that the maximum depth allowed is clear to the operator. Respecting these
premises, the needle indenting externally the vein and its tip within the lumen confirm the
correct execution.
Clip 23 illustrates ultrasound-guided cannulation of an internal jugular vein. It is started from
the left in relation to the left dominance. e end of the clip shows the ultrasound images
of the puncture, the metal guide and the catheter into the lumen.
Clip 23 – Ultrasound-guided cannulation of an internal jugular vein.
Figure 43 illustrates the sequence of an echo-guided cannulation of the internal jugular vein.
Figure 44 illustrates the needle approaching the vessel on the screen.
Some years ago, Jernigan and coworkers described a blind approach to the internal jugular
vein lateral to the sternocleidomastoid muscle. According to this technique, the needle is
inserted two transverse fingers above the clavicle, under the lateral border of the clavicular
head of the SCM muscle, at 45° toward the suprasternal notch. is approach is ideal for
ultrasound, because it shows an axial view of the jugular vein, with in plane access of the
needle (so the entire needle is visualized). e probe is placed transversally over the muscle
and the needle enters the vessel laterally.
With this access, the vascular puncture is made with a wide angle with respect to the vascular axis. For this reason, once the needle is in the lumen, it is directed downwards so as to
introduce the guide wire in axial position into the vessel lumen.
e echo-guided puncture of the internal jugular vein shows a negligible risk of pneumothorax.
In a recent paper, no pneumothorax occurred on 1262 interventional procedures. is permits
to postpone the post-procedural chest X-ray, especially if the presence of pneumothorax may
be excluded by ultrasonography
94
. In spite of this, the use of ultrasound for the placement of
internal jugular catheters is not widespread (only 35% of intensivists in the United Kingdom)95.
e ultrasound guided subclavian vein access is more difficult, especially for the position of
the vessel behind the clavicle. is situation makes the probe/needle coupling complex. In
other words, frequently it is not possible to associate needle and probe in a single scan, and
often, for reasons of space, a perfect needle positioning is not possible. is confuses the
inexperienced operator and can be the cause for drawbacks, such as a the blind puncture.
e technique described by Gualtieri96 involves “in plane” cannulation, if the probe is not
large. According to this technique, the subclavian vein is identified caudally and laterally to
the distal part of the clavicle. e probe, oriented longitudinally with the vessel, is moved 2-3
cm medially to the classic point of needle insertion for the subclavian approach. In this way,
holding the probe (possibly small) in one hand and the introduction system in the other, it
is relatively easy to create a scan plane that allows to direct the needle toward the vessel, away
from the pleural dome97 (Fig. 45).
484 oracic ultrasound
Figure 43 – Ultrasound-guided insertion sequence of a catheter into the right internal jugular vein
(introducer method). Note the position of the operator behind the patient’s head and the coating of the
probe with a sterile drape. The puncture of the vein is performed under ultrasound guidance with the
probe placed transversely on the vessel and the guide wire passed into the vein through the needle. The
insertion of the introducer on the guide wire can be observed: it allows the passage of a soft catheter.
Finally, the introducer is removed from the vessel separated into two halves (peel away introducer).
Figure 44 – This is the image observed on the screen by the operator during cannulation of the right internal
jugular vein under ultrasound guidance, while standing behind the patient’s head. The needle that penetrates
beneath the skin and is close to the vein is identified by its shadow. Note the trachea located to the left of the
screen and the carotid artery posterior-medially to the vein.
However, this method is not always feasible for anatomical reasons. e better anatomy is when
the subclavian vein has a quite long lateral subclavian course, such as to allow the positioning
of a small linear probe in plane with the needle. Otherwise, in this position the probe should
be placed transversely on the vessel and the needle insertion should be perpendicular to the
long side of the transducer (out of plane).
Ultrasound may be an excellent aid to access the subclavian vein at the level of its junction
with the axillary vein (so-called transpectoral access to the subclavian vein). is procedure
is very safe, because the risk to injure important structures is negligible98 for the extrathoracic
position of the vessel. With the patient’s limb abducted, puncture is made through the anterior
Interventional chest ultrasound 485
axillary pillar, on which the transducer is placed. With just a light pressure, the axillary vein
is seen approaching to the rib-clavear space before entering the chest.
Clavicle
Subclavian Vein
Pleura
Figure 45 – Transverse ultrasound image of the subclavian vein in its middle section, illustrating its
relations with the clavicle and the pleura (5 mm).
We believe that the transpectoral access to the right subclavian artery may play an important
role between the modern ultrasound guided vascular cannulations (Fig. 46).
Needle
route
Axilla
Figure 46 – Transpectoral access to the right subclavian vein.
1. rib
486 oracic ultrasound
e supraclavicular area may also be approached under ultrasound guidance.
e medial retroclavicular segment of the subclavian vein, and its proximal junctional segment
are represented by ultrasonography when the probe is placed in the medial supraclavicular
fossa, along the insertion of the clavicular head of the sternocleidomastoid muscle. According
to this projection, the medial subclavian vein and the subclavian-jugular venous lake clearly
appear on the scan. For accessing the subclavian vein, the needle is inserted in plane with
the ultrasound beam. For acquiring the subclavian-jugular junction, an out of plane access
is performed. e supraclavear approach is particularly uncomfortable. Table 15 summarizes
the advantages of the use of ultrasound in the placement of central venous catheters.
Table 15 – Role of ultrasound in the placement of venous catheters
• It provides an anatomical evaluation helpful to choose the best access site
• It creates an optimal imaging for the assessment of the vein’s patency, its course and the
presence of valves
• It provides a definition of the local anatomy
• It defines anatomical variations on the position of the patient’s body or head
• It allows to choose a catheter gauge adapted to the venous morphology
• It allows the penetration of the needle through the tissues and the vessel wall under visual
control
• It allows the passage of the guide wire into the vessel lumen under visual control
• It allows to more easily detect local complications
Some pitfalls for the positioning of catheters
e well-known anatomical variability of the internal jugular vein is overcome by ultrasound
preliminary study of the vessel and by the assessment of its patency (full compressibility).
is survey is important for evaluating the presence of thrombotic formations in the lumen
(Clips 24-25).
Clip 24 – Complete thrombosis of an internal jugular vein.
Clip 25 – Partial thrombosis of a right internal jugular vein.
For the safe puncture of the subclavian vein it is crucial to know its relationships with the
subclavian artery, the first rib, the clavicle and the anterior scalene muscle. In our opinion,
the echo-guided puncture of the subclavian vein is reserved for experienced operators, since
the visualization of the needle can be easily lost and the pleural dome is very close to the
puncture site.
Often the relationships of subclavian vein are not well explained in the texts that describe the
anatomy of the upper thoracic regions or percutaneous catheterization techniques.
Interventional chest ultrasound 487
Many times, a wide space between clavicle and first rib is described and illustrated, and the
vein simply passes through this space. However, the vein is often parallel and fully adherent to
the middle third clavicle or, in other circumstances, it passes over the first rib with a marked
curve and lies within a small space almost perpendicular to the clavicle.
When the needle is inserted exactly in the engaging between clavicle and first rib, the so
called “costoclavicular scissor”99 occurs. e intravenous catheter is pressed between two
rigid surfaces with an increased risk of injury, stenosis, fibrosis or breakage. is effect can
be overcome by puncturing the vessel more laterally, but this operation, in the absence of
valid skin landmarks, requires the aid of some imaging method.
e “transverse plane” phenomenon is related to the use of ultrasound. It occurs when the
needle tip is not located in the thickness of the ultrasound beam, which is very thin (2-3
100
mm)
. In this case the ultrasonic lines of sight may not show the tip, situated in a contiguous plane, but a proximal portion of the needle, misinterpreted as the tip advancing in the
tissues. So the real tip may be pushed beyond the target, causing injury in adjacent structures.
is can only be avoided by keeping the terminal part of the needle exactly within the image
plane throughout its route.
e passage of the needle in plane with the probe is much more useful in order to maintain the
whole penetration route within the ultrasonic lines of sight. Sometimes it can not be easy to be
realized, especially because of difficult skin contact, in complex regions or with large probes.
Scanning at internal jugular level the phenomenon of systolic jet may occur, so the local
anatomy is distorted according to the moments of the cardiac cycle. Sometimes, during
each systole, a large and tortuous common carotid artery may dislodge the adjacent jugular
vein and compress it, altering the balance of a needle introduced, that could hit organs and
adjacent structures.
Postprocedural control
After cannulation of the great vessels, ultrasonography is an excellent method for a postprocedural control at the bedside. is control may be addressed to any complications of the
procedure (pneumothorax, hemothorax, hematoma, dissection, vascular occlusions, and so on).
Moreover, the postprocedural control discovers misplacements or dislocations of the catheter.
Local complications occur as perivascular hematomas that may compress the venous vessel,
making any further attempt to puncture impossible. Wall dissections and iatrogenic arteriovenous fistulas are rare. Venous thrombosis is a usually late complication, with echographic
signs already described.
Serious immediate complications are hemothorax and pneumothorax. PNX has an immediate
diagnosis through echographic signs. In particular the disappearance of pleural sliding with the
absence of any artifact of visceral pleural origin, and the eventual appearance of lung points
101
e iatrogenic hemothorax is evident as pleural fluid collection that was not present before.
Ultrasound can be used as a control for the correct positioning of the venous catheter and
some recent evidence suggests its use as an alternative to postprocedural chest X-ray
102
.
Catheters inserted in the internal jugular vein very rarely end in the subclavian vein, but the
opposite is more frequent. A catheter inserted into the subclavian vein is easily seen inside
the vessel through a subclavian position. A scan of the jugular vein immediately shows the
presence of a misplaced subclavian catheter. A venous catheter placed into the right atrium or
right ventricle may be seen with a cardiac subcostal scan (which also allows the visualization
of the inferior vena cava), or performing a 4 chambers apical scan. In case of uncertainty,
.
488 oracic ultrasound
stirred saline solution is injected through the catheter generating an effective vascular contrast.
Microbubbles in the fluid act as scatterers, and are seen as a clear narrow jet from the tip of
the catheter. A perfusion through a catheter placed in the superior vena cava generates a wide
echocontrast flow transported into the right atrium. is kind of echocontrast is much more
widespread when the tip of the catheter is far from the heart (Clips 26-27).
Clip 26 – Subclavear scan of the right subclavian vein: the presence of the
catheter in its lumen is observed.
Clip 27 – Subcostal long axis caval vein scan. The correct placement of the
catheter is confirmed by the arrival of microbubbles from the superior vena
cava to the right heart cavity.
Ultrasound-guided central venous access in pediatrics
In 1994 Orlowski said “my kingdom for an intravenous line”
103
. is is particularly true in very
young children and neonates.
e techniques discussed in the previous pages for adults also applies in the pediatric popula-
tion, although with a lesser quantity of data. Sonography is an important aid to facilitate vein
cannulation in children. Moreover, many related thoracic complications may have an early
ultrasound diagnosis
104
. Central venous catheters in children can be inserted into the femoral,
the internal jugular or the subclavian vein. Table 16 summarizes some of their characteristics.
Blind cannulation in the subclavian vein in children has a significant complication rate, which
varies between 3% and 34% and is significantly higher than the internal jugular puncture.
Its major complications are PNX and arterial puncture.
e ultrasound-guided puncture of the internal jugular vein does not expose to risks relating
to variations in size and position of the vessel. Cannulation rate of this vessel in children
increases from 25% up to 100% using echography. Under ultrasound guidance, puncture
of the carotid artery is avoided in the totality of the cases. Venous thrombosis is rare and the
risk of pneumothorax is minimum.
As in adults, ultrasound-guided puncture of the subclavian vein (usually the preferred venous
access) in children is technically more difficult than accessing the internal jugular vein. is
difficulty is due to the complex coupling of the scan plane of the linear probe with the vessel,
when it passes between clavicle and first rib. On the contrary, it is easy to produce a clear
image of the vein alongside of the clavicle, placing the probe in infraclavicular position. An
infraclavicular puncture allows access to the subclavian vein with the needle in plane through
the axillary vein, or the junction of the subclavian with the axillary vein. is technique
resembles the transpectoral axillary-subclavian access previously described for adults. In our
opinion, this is a relatively easy and safe procedure for the optimal visualization of the target
and its extrathoracic location. However, for a safe approach, it is essential to differentiate the
artery from the vein, and identify the cephalic vein and the arterial branches near the anterior
axillary pillar (acromial branch of thoraco-acromial artery, lateral thoracic artery).
If a classic infraclavicular access is used, the probe may be located in the medial supraclavicular area in order to recognize the two bony landmarks represented by the clavicle and the
first rib. In this scan the subclavian vein is easily viewable between these two bones in its
Interventional chest ultrasound 489
Table 16 – Advantages and disadvantages related to different venous access, including intraosseous
access in the pediatric age
Access
to emergency
Intraosseous
access
Subclavian
vein
Femoral vein +++ +++ ++ ++ + ++ +++
Internal
jugular vein
External
jugular vein
Axillary vein + + + + + + +++
Surgical
exposure
0 = no efficacy / no risk / not suitable.
Modified from: Haas NA. Clinical revew: Vascular access for fluid infusion in children.
2004; 8: 478.
++++ ++++ + 0 + 0 ++++
++ ++ ++ + ++ +++ ++
++ ++ ++ + + ++ +++
+++ +++ + + 0 + ++
++ + ++ ++++ 0 0 ++
Easiness Infection Thrombosis Other
complications
Prolonged
use
Critical Care
Shortterm
use
intrathoracic route. e insertion of the needle, in plane with the probe, takes place in real
time with lateromedial and inferior-superior direction, aligned with the vein (from which it
is separated by the first rib) and away from the pleural dome
the subclavian vein in children is also described
106
. Longitudinal or transverse scans identify
105
. A supraclavicular access to
the internal jugular vein’s relations with the carotid artery and the SCM muscle. is allows
to implement ultrasound-guided access
107-108
of the internal jugular vein, as in adults.
For reasons of space vascular cannulation is usually perpendicular to the scan plane of the
linear probe placed transversely on the neck. For anatomical reasons the access on the right
(linearity of course to the superior vena cava, absence of thoracic duct) is preferable, and
thoracic complications are exceptional. Postprocedural control for PNX is easily performed
with anterior pleural scans, following the indications given in the section on pleural diseases.
Role of ultrasound in monitoring the position of central venous catheters
in newborns
e writing of this chapter was carried out with the cooperation and contribution of Dr. Luigi
Cattarossi (Director SOC Neonatal Pathology, University Hospital Santa Maria della Misericordia,
Udine).
To control a central venous catheter placed through an umbilical vein a chest radiograph is
usually performed. In our experience, the use of ultrasound allows a precise control of the
catheter site, so the execution of the radiograph can often be postponed.
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