66 / 176
710
Removal
After catheter removal, press firmly on the site for at
least 5 min. Persistent bleeding may require a fine suture
(e.g. 5/0 nylon), to close the skin wound and stabilize
clot. Radiological occlusion devices are greatly improved
and required for removal of devices larger than 9Fr, in the
presence of severe coagulopathy, or in areas where pres-
sure cannot be applied.
Complications
Complications can be divided into early and late, but
some will be delayed in presentation (Table 6). Vascular
compromise may occur at any stage. Accidental arterial
injection of drugs is an important avoidable complica-
tion. Risks of infection increase with time and arterial
catheters can cause catheter related blood stream infec-
tions. If concerns arise as to arterial patency and distal
circulation, then urgent referral to vascular surgery is
indicated.
and most sites of access (40), particularly for the IJV in
terms of first pass success and complications (10), with the
following advantages
• Direct imaging of vessels and adjacent structures
• Imaging of thrombosis, valves, dissection, atheroma, or
anatomical variants
• Identification of optimal target vessel
• First-pass access avoiding adjacent structures
• Confirmation of guidewire and catheter in vessel
• Reduces procedural complications
Veins show respiratory variation (with a free connection
to right atrium), and are easily compressible. Arteries
are round and non-compressible, and become clearer
to image with pressure. Peripheral arteries have charac-
teristic double vena comitantes. If in doubt, use colour
Doppler to differentiate pulsatile from a more continuous
venous signal. Limb veins will showenhanced signal if the
distal limb is squeezed or the patient contracts muscles.
The display should anatomically be in the orientation as
seen from the position of the operator.
Correct orientation ensures that the image moves in a
logical direction when the probe is moved and that the
needle moves in the same direction in the patient as on
the display.
Precise needle tip imaging is vital. The needle and ultra-
sound probe may be arranged in the ‘short (out-of-plane)’
or ‘long (in-plane)’ axis and the image axial or longitudinal.
An axial vessel view and short-axis needle insertion gives
good visualization of surrounding structures but it takes
experience to achieve good needle tip imaging as the
shaft can be mistaken for the tip.
Better needle images are seen if the needle inserted in the
long axis but if the vein is imaged longitudinally concur-
rent images of surrounding structures are not seen. Some
needles have their distal section machined to increase
echogenicity (41). Training and accreditation issues related
to ultrasound are important (42).
CONCLUSION
Vascular access is a core skill needing anatomical knowl-
edge and practical skills. Recognition and management
of complications is essential. The increasing use of ultra-
sound, ECG guidance, and X-ray screening, and improved
design of devices allows safe and successful procedures.
Many patients now benefit from early use of long-term
access devices.
[REV. MED. CLIN. CONDES - 2017; 28(5) 701-712]
•
Early
•
Bleeding
•
Haematoma
•
Arterial damage (dissection, thrombus, embolism).
•
Late Thrombosis Embolism Nerve injury Infection
•
Catheter dislodgement, fracture, embolism
•
Arteriovenous fistula.
TABLE 6. COMPLICATIONS OF ARTERIAL CATHETERISATION
ULTRASOUND GUIDANCE
Ultrasound imaging is not yet used routinely to cannu-
late arteries, although studies are increasingly suggesting
benefits, not just in difficult cases (39). Such guidance
is useful with low blood pressure, atheromatous vessels,
stenosis, dissections, thrombosis, oedema, obesity and
variations in anatomy. It is likely that the frequency of
procedural and infectious complications is related to the
number of needle passes. Other deeper sites, for example,
the radial and ulnar arteries in the mid forearm can also
be used.
General Principles of ultrasound guidance
There is a strong evidence for use of ultrasound in all ages