Advances in ultrasound-guided radial artery puncture catheterization

Author: Bai Bing, Tianyuan, Yu Chunhua, Department of Anesthesiology, Peking Union Medical College Hospital

Arterial puncture catheterization is usually used in critically ill or patients undergoing major surgery, through the invasive ductus arteriosus, real-time monitoring of blood pressure, so that clinicians can adjust the dose of vasoactive drugs in a timely manner, maintain the patient's hemodynamic stability, and can also easily and conveniently obtain arterial blood for blood gas analysis
.

Arteriocentesis catheterization is one of the essential skills of anesthesiologists, but when encountering conditions such as newborns, excessive obesity, shock, edema, arterial spasm, etc.
, the operator may face challenges such as repeated punctures, replacement of puncture sites, local hematoma, or
even failed punctures.
The radial artery is superficial and co-supplies blood to the hand with the ulnar artery, and the complication rate is relatively low, making it the preferred site
for arterial puncture catheterization.

Studies have shown that ultrasound guidance can improve the success rate of arterial puncture catheterization and reduce the incidence of related complications
.
In recent years, ultrasound-guided technology has developed rapidly and is becoming more and more widely used in clinical practice
.
Researchers have been trying to improve ultrasound-guided radial artery puncture in the hope of improving the one-time success rate
.
This article reviews the advantages and disadvantages of ultrasound-guided arterial puncture catheterization, the recommended use of ultrasound-guided patient populations, the different methods of ultrasound guidance, and the sterility principles of ultrasound guidance
.

1.
Advantages and disadvantages of ultrasound-guided arterial puncture catheterization

Pros: Ultrasound can show the target blood vessels and surrounding tissues in
real time.
Placing the probe along the long axis of the vessel reveals a complete radial artery, and along the short axis a radial artery cross-section and surrounding structures
can be seen.
Ultrasound can be used for vascular screening before operation to exclude thrombosis, occlusion, etc.
, and change clinical decisions
in a timely manner.
Compared with traditional palpation, ultrasound guidance can be used in adults, children, and neonates to improve first-time success, shorten the time of operation, and reduce complications
.

Cons: The effect of ultrasound on the risk of infection is controversial, and if it is not in accordance with the principle of sterility, there is a risk of
infection.
At present, equipment factors largely limit the normalization of ultrasonic guidance, and the purchase cost of ultrasonic equipment and post-maintenance costs limit its promotion
.
In addition, although the superiority of ultrasound is premised on the fact that the operator has been trained in the norms, otherwise it may be counterproductive
.
Standardized training should have a corresponding number of training experts, and sufficient training teachers are guaranteed, which is also the current shortage of resources
.

2.
It is recommended to use ultrasound-guided patient groups

Given the advantages of ultrasound guidance, it is recommended that ultrasound guidance be routinely used during arterial puncture catheterization, and that all radial artery puncture catheterists be trained
in ultrasound guidance procedures.
Limited by equipment, manpower, financial resources and other factors, the vast majority of medical institutions have not yet met the conditions for the routine use of
ultrasound guidance.
Limited by realistic factors, it is more common to use ultrasound guidance
when encountering difficulties.

Difficulty puncture: In some conditions such as edema, obesity, aortic arteritis, or other difficult-to-pallate arterial pulses, other sites may be selected without ultrasound, or repeated blind penetrations may cause potentially excessive damage to the patient, and ultrasound guidance may help
.

Puncture history: for patients with a previous history of arterial puncture, such as patients with coronary heart disease who have recently undergone percutaneous coronary angiography, if the same site is required for puncture and placement, the traditional palpation method cannot determine whether the blood vessel has been damaged by recent operation such as dissection, local hematoma, etc.
, and ultrasound can be considered to evaluate the vascular situation and select a suitable puncture site
.

Coagulation dysfunction: If the patient has a known coagulation dysfunction or has a clear bleeding tendency, the probability of local hematoma injury once penetrated the posterior wall will be greatly increased, and it will also make subsequent operations difficult, such as the use of ultrasound guidance for the first operation, which may improve the success rate and reduce unnecessary damage
.

Hemodynamic instability: Ultrasound guidance
may be considered for low blood pressure due to circulatory instability such as hypovolemia, severe arrhythmias, cardiac insufficiency, or failure when the radial artery is difficult to palpable.

Other: There are some special cases in clinical practice, other arteries are not available, radial arteries are the only option, if the operation fails, there is no alternative, the use of ultrasound guidance can be considered in order to improve the success rate
of the first time.

3.
Different methods of ultrasound guidance

The commonly used ultrasound-guided radial artery puncture catheter mainly includes transverse and longitudinal methods, as well as various improved methods
derived from it.

Lateral method: The transverse method is the extra-planar method, and the probe is perpendicular
to the blood vessel.
Advance the needle at the midpoint of the probe and the direction of the needle is perpendicular
to the transverse direction of the probe.
If the orientation is correct, the tip will enter the screen
from the center.
Keep the probe perpendicular to the blood vessel, the tip of the needle and the image of the blood vessel aligned, otherwise you will miss the blood vessel
.
If the blood vessel is missed, adjust the direction of the needle so that the tip of the needle is aligned with the blood vessel
.

Longitudinal method: The longitudinal method is the intraplanar method, and the probe is parallel
to the blood vessel.
Enter the needle at the midpoint of the probe side in parallel to the probe
.
From the screen, the needle enters the field of view
from one side.
When the needle reaches the appropriate depth, the screen shows the tip of the needle entering the blood vessel
.
However, sometimes the needle is actually staggered parallel to the blood vessel, and it seems to see the needle enter the blood vessel on the screen, but in fact, there is no blood
back.
This is where repositioning and puncture are
required.

Berk et al.
evaluated the lateral and longitudinal methods of subjects undergoing heart surgery and found that the longitudinal method shortened the time to successful catheter placement, improved the success rate of the first attempt, and reduced complications
.
Quan et al.
evaluated the lateral and longitudinal methods of subjects undergoing liver or spleen surgery
.
The success rate of the first attempt at the lateral method is higher, and there is no difference in
the time required and the incidence of complications.
The transverse method shows images of perivascular tissue and helps guide the needle to the arterial cavity, but it is difficult to keep the tip within the plane of the ultrasound beam, and the probe needs to be adjusted frequently to keep the needle tip visible
.

The longitudinal method can directly see the needle through the tissue into the artery process, but it is difficult to keep the tip of the needle and the nearby structure in the central axis of vision, and sometimes it may "deceive" the operator, so that the operator mistakenly believes that the needle has entered the artery but has not actually returned blood
.

Diagonal method: Abdalla et al.
define the oblique method, which is based on the transverse method to rotate the probe clockwise by 30° to 60° to maximize the arterial field of view, improve the success rate and operator satisfaction
.
The diagonal method allows for better observation of the needle tip and increased observation of the surrounding structure, ensuring safety
.
The oblique method is intended to broaden the visualization area of the horizontal method and combine
the advantages of the longitudinal method needle tip visualization.

There is no conclusion on how to choose the lateral, vertical and oblique methods, and it is recommended that operators use the methods
they are best at.

Dynamic needle tip positioning: Goh et al.
first reported dynamic needle tip positioning (DNTP) for radial artery puncture catheterization
.
Clemmesen et al.
found that the DNTP method has a higher success rate
in venipuncture catheterization than the planar method.

In recent years, Kiberenge et al.
have found that the overall success rate and one-time success rate of DNTP method are higher than those of traditional palpation methods
.
The DNTP method requires first finding the short axis of the radial artery, entering the needle at about 30°, and after seeing the needle tip, move the probe proximal to the proximal end away from the needle entry point until the needle tip disappears
.
Then enter the needle again until the tip
of the needle is seen again.
Repeat this step until the tip of the needle is seen in the lumen of the artery
.
Reduce the angle of needle entry and continue the needle in the same procedure, keeping the tip of the needle in the center of
the artery cavity.

This method requires that the catheter should not be placed just by seeing the return of blood, but by reducing the angle and continuing to enter the needle until the tip of the needle and the catheter are re-catheterized in the vascular cavity
.
Oh et al.
recently used the puncture model for the teaching of DNTP and achieved satisfactory teaching results
.
The DNTP method is one of the most recognized and respected methods at present
.

Developer line method: Some researchers have improved on the basis of the extra-planar method, fixing a development line perpendicular to the long axis in the middle position of the probe, that is, the development line method
.
This line displays visible markings on the ultrasound screen, improving the accuracy
of the needle entry point.
The puncture point is the intersection of the development line and the skin, and the puncture process does not use dynamic techniques
.
One of the reasons for the low success rate of arterial puncture among interns is that the positioning is incorrect
.
This method is simple and accurate in locating the puncture point, especially for novices
.

Normal saline method: Nakayama et al.
improved the extraplanar method in pediatric patient groups and proposed the saline DNTP method
.
They believe that the success rate of puncture is low when the artery depth is less than 2 mm, and that subcutaneous injection of saline will artificially increase the depth, thereby reducing the manipulation time and improving the success rate
.
Ye et al.
use the saline DNTP method for radial catheterization in newborns, which is equally safe and effective
.
This approach
is recommended for patients with overly superficial arteries.

Modified in-plane method: Wang et al.
have improved the intraplane method, that is, modified long-axis in-plane ultrasound technique (M-LAINUT
).
Compared to conventional palpation, the M-LAINUT method significantly improves the success rate, reduces the number of punctures and shortens the duration of
the procedure.
This method first acquires the image of the long axis of the artery, opens the color Doppler to obtain the arterial blood flow signal, and the location with the richest blood flow signal is the largest diameter of the artery, that is, the puncture point
.
A short axis image of the artery can be obtained first, and then the probe is rotated 90°, helping to obtain a long axis image
.
Wang et al.
have shown that this approach is easy to master and effective
.
It can be adopted for both novice and skilled operators
.

Magnetic navigation assistance: The needle navigation system is to magnetize the needle in advance, and the ultrasonic machine automatically locates the position of the needle and displays the virtual path of the needle for the operator's reference
.
In 2016, Meiser et al.
found that the success rate of a puncture using a navigation system and the overall success rate were higher and less time-consuming, which was helpful
for novices.
Johnson et al.
believe that magnetic navigation assistance can improve puncture accuracy
.
At present, this method is not widely used and still needs further study
.

Non-real-time guided ultrasound assistive method: blood vessels are identified by ultrasound and used to make sterile labels
on the skin.
This method is inferior to real-time ultrasound guidance and is rarely used
.
In some cases, such as when an ultrasonic probe cannot be sterile treated, it may be an alternative
.

4.
Ultrasound-guided sterility principle

When performing ultrasound-guided radial artery puncture catheterization, the principle of
sterility should be strictly observed.
The use of chlorhexidine impregnated sponges reduces catheter-associated bloodstream infection
.
Pay attention to hand hygiene, place a "sterile operation in progress" sign outside the door, and wear a hat and mask
for everyone present.
Precautions
for bloodstream infection associated with a central venous catheter may be applied as appropriate.
It is recommended to use a skin disinfectant containing 2% chlorhexidine
.
Ultrasonic probes require sterile handling
.
It is recommended to hold the ultrasonic probe with a non-dominant hand to ensure operator comfort
.

In summary, ultrasound-guided arterial puncture catheterization technology has developed rapidly and is becoming more and more widely used in clinical practice
.
There is growing evidence that ultrasound guidance improves puncture success and reduces associated complications
.
Clinical operators should fully understand the advantages and disadvantages of ultrasound guidance, combined with the actual factors of the specific clinical environment, and recommend it for use
in suitable clinical patient groups.
There are various methods of ultrasound-guided arterial puncture, each with advantages and disadvantages, and suitable methods
should be selected as appropriate in clinical practice.
Regardless of which method is used, always pay attention to sterility principles and procedures to reduce the risk of
infection.

Source: Bai Bing, Tianyuan, Yu Chunhua.
Research progress on radial artery puncture catheterization under ultrasound[J].
Journal of Chinese Academy of Medical Sciences,2022,44(02):332-337.