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The Sonic Window:
A Novel Vascular Access Device
The Sonic Window:
A Novel Vascular Access Device
Michael Blaivas, MD, FACEP, FAIUM
Introduction
Ultrasound guidance for vascular access dates back more than 20
years, but the last decade has seen it spread broadly throughout
clinical practice as a common point of care ultrasound application.
Initial research focused on the utility of ultrasound in providing
guidance for central venous access. Multiple studies showed
it decreased complications and increased first pass success in
internal jugular, femoral and subclavian central line placement.1,2,3
However, despite focus being held firmly on central venous access,
it became obvious that ultrasound guidance had considerable
utility in peripheral venous cannulation, saving time, money and
improving success rates for first cannulation attempts.4,5
Ultrasound guidance allowed a variety of practitioners, including
physicians and nurses, to place peripheral lines into extremely
challenging patients at the point of care and in many cases, to
avoid central venous access. The utility in doing so is several fold.
Complications associated with central line placement include
hemorrhage, thrombosis, infection, pneumothorax, airway loss
and death. Such serious complications are not associated with
peripheral venous lines and if the risk of these complications can
be avoided completely because the need for central venous access
is obviated, then patients, hospitals, providers and society would
benefit. Even ultrasound guided central line placement cannot
avoid some complications such as infection and thrombosis, yet
not having to place a central line at all, can.
Because some central lines are placed solely for the purpose
of vascular access, even when central venous access is not truly
required, there is an opportunity for immediate decrease in
morbidity, mortality and cost. Two recent studies have confirmed
that introduction of ultrasound guidance for peripheral intravenous
line placement significantly decreases the use of central venous
access.6,7 In fact, the drop is as large as 81%, with much of
the decrease occurring in non-critically ill patients. Therefore,
ultrasound is exceedingly helpful in decreasing central line
associated complications even without being used for central line
placement, by simply improving the capability of vascular access
providers of all levels to obtain peripheral venous access.
A variety of ultrasound devices are available, ranging in size and
price from the small to the very large. The point of care setting
typically calls for a more rugged, compact and less expensive
ultrasound device, which can be utilized for a wide variety of
ultrasound applications. Many departments and units cannot
dedicate such a device for vascular access only and providers may
compete for availability with other uses such as cardiac, trauma,
lung, abdominal, vascular and soft tissue ultrasound applications
being performed at the point of care. What is needed is a small,
easy-to-use and more affordable ultrasound device specifically
designed for vascular access and tailored to peripheral venous line
placement. Such a device should be intuitive to use and be easy
to handle.
1 Fragou M, Gravvanis A, Dimitriou V, Papalois A, et al. Real-time ultrasound-guided subclavian vein
cannulation versus the landmark method in critical care patients: a prospective randomized study. Crit
Care Med. 2011 Jul;39(7):1607-12.
2 Hind D, Calvert N, McWilliams R, Davidson A, et al. Ultrasonic locating devices for central venous
cannulation: meta-analysis.BMJ. 2003 Aug 16;327(7411):361.
3 Hilty WM, Hudson PA, Levitt MA, Hall JB. Real-time ultrasound-guided femoral vein catheterization
during cardiopulmonary resuscitation. Ann Emerg Med. 1997 Mar;29(3):331-6.
4 Brannam L, Blaivas M, Lyon M, Flake M. Emergency nurses’ utilization of ultrasound guidance
for placement of peripheral intravenous lines in difficult-access patients. Acad Emerg Med. 2004
Dec;11(12):1361-3.
5 Costantino TG, Parikh AK, Satz WA, Fojtik JP. Ultrasonography-guided peripheral intravenous access
versus traditional approaches in patients with difficult intravenous access. Ann Emerg Med. 2005
Nov;46(5):456-61.
*Sonic Window is not cleared for sale in the EU.
6 Shokoohi H, Boniface K, McCarthy M, Khedir Al-tiae T, et al. Ultrasound-guided peripheral intravenous
access program is associated with a marked reduction in central venous catheter use in noncritically ill
emergency department patients. Ann Emerg Med. 2013 Feb;61(2):198-203.
7 Au AK, Rotte MJ, Grzybowski RJ, Ku BS, Fields JM.Decrease in central venous catheter placement due to
use of ultrasound guidance for peripheral intravenous catheters. Am J Emerg Med. 2012 Nov;30(9):1950-4.
The Sonic Window:
A Novel Vascular Access Device
The Sonic Window
The Sonic Window is like no other vascular access device available.
While it is an ultrasound device, at first glance the images it displays
may not be familiar to most users. This is simply because of the
scanning format utilized. Instead of a two-dimensional image that
is vertical from the skin surface projecting deeper into the tissue,
the Sonic Window displays a coronal tissue slice. This is similar to
how CT and MRI scans are traditionally displayed, except the slices
are oriented horizontally and stacked from skin surface down. The
sense novice users attain from first operating the device is that they
are able to look at individual tissue slices from just underneath the
skin down to 3 cm in depth. Depth is controlled by an easy-to-use
thumb operated slider mechanism, giving the operator precise and
easy control over ultrasound slice depth selection. Additionally,
the slider is specifically designed to allow easy and rapid scrolling
through multiple tissue slices in order to identify vessels at different
depths.
Another notable difference from conventional point of care
ultrasound machines is the form factor of the device. It is small,
resembling a smart phone or remote control. The Sonic Window
is easily held in one hand, leaving the other hand to manipulate a
needle or an IV.
Site Selection
As with any ultrasound guided vascular access procedure,
appropriate site selection is important. Basic venous anatomy
knowledge is important in order to select sites that are likely to
contain accessible, but not previously used veins. These include
the upper medial arm where the paired brachial veins and basilic
vein are often accessible for cannulation. The cephalic vein on the
opposite side of the upper arm is an option in some patients and is
rarely cannulated blindly. The forearm and dorsum of the hand and
wrist may contain slightly deeper veins that cannot be palpated or
seen. However, one of the richest untapped areas in patients is the
proximal antecubital fossa. This is an area familiar to many nurses,
but in the case of no palpable veins, one can move slightly more
proximal where these same veins may be accessible, but are often
too deep to palpate. It is an area worthy of a quick look.
Simply place the Sonic Window on top of the area of interest after
applying ultrasound gel and scan from the surface down a couple
of centimeters. This is accomplished with a quick move of the
thumb down the depth slide. A vessel, when located, will appear
to be a dark or black channel cutting through the background
of classic gray scale tissue or an orange mat, if selected, Figure 1.
Aligning the vessel so that it runs across the screen of the Sonic
Window from one side to the other ensures that the needle can be
inserted using the guide markers on either side of the device and
help the provider line up directly over the vessel. Driving down at
the appropriate angle, usually shallow, the needle appears on one
side of the screen and the flash is seen in the hub almost at the
same time, Figure 2.
Figure 1: Image of an actual patient’s vein prior to cannulation. Notice the
accurate depiction of the rough contour and some tortuosity of the vein. This was a
dialysis patient with a history of cancer and diabetes who was a severe vasculopath
and was about to receive a central catheter just for hydration and intravenous
medications. Blind attempts were repeatedly unsuccessful.
Figure 2: The image shows a vein as it is being cannulated. The arrows on the right
side of the screen point to the needle entering the vein. A flash was obtained as the
needle was seen.
The Sonic Window:
A Novel Vascular Access Device
Clinical Experience
Fortunately, it was easy to test the Sonic Window in a busy
emergency department with high acuity patients. Eight patients
were scanned and cannulated. Only one attempt resulted in no
veins being located and the absence of any target was confirmed
with a conventional ultrasound unit. All others resulted in candidate
vein localization and successful cannulation. Vein location included
antecubital, cephalic, basilic, forearm veins as well as an external
jugular. Several clinical examples are noteworthy.
staff reported that no blood could be pulled back for additional
blood work shortly afterward. Scanning the cannulation site again
with the Sonic Window revealed that the catheter was seated
well in the vein and flushed in the lumen only. Fluid resuscitation
continued uneventfully through the IV and blood was pulled
back successfully at a later time for follow up laboratory analysis.
The first was a chronically ill 67-year-old woman on dialysis. After
multiple failed blind attempts, the patient was scanned with the
Sonic Window. She had few vascular access options peripherally.
A new dialysis graft was located in the right arm and an old one in
the left. No other sites were found. However, located adjacent to
an old, non-functional graft there lay a hidden, unused vein, Figure
3. The Sonic Window allowed easy differentiation of the vein from
the old graft and the brachial artery. Patency was confirmed and
cannulation successful.
Another noteworthy patient was a 20-year-old non-compliant
diabetic man who was a frequent ED user. The patient typically
received a central line, for hydration, IV insulin and anti-emetics, due
to lack of peripheral vascular access options. His external jugular
veins were used up previously and could no longer be palpated or
seen. Interrogation of the common deep peripheral venous access
sites showed multiple scarred and thrombosed veins. However,
the Sonic Window revealed a patent right external jugular close
to the clavicle. Cannulation was successful; however, nursing
Figure 3: An arm with an old dialysis graft that had no obvious veins, yet held a
good vein for cannulation, found with the Sonic Window.
Sonic Window Handheld Ultrasound
Designed to improve first stick success of
Peripheral Intravenous Access
For more information visit: bkultrasound.com/sonicwindow
sonicwindow
*Sonic Window is not cleared for sale in the EU.
The Sonic Window:
A Novel Vascular Access Device
Additional Utility
There is additional utility to the Sonic Window when placed into the vascular access provider’s hand. When doubt exists about the identity
of a vessel, either artery or vein, the Sonic Window offers a unique solution. Compression of the area will cause a normal vein, suitable for
cannulation, to slowly disappear and appear to fill in. An artery however, or a thrombosed or scarred vein will not, Figure 4.
Figure 4: In this series of three images a vein (vertical arrows) is seen running across the screen arrows. As compression is applied, it collapses, confirming patency. The
middle image shows the filing in process occurring as the venous lumen collapses under pressure. Due to the angle of the arm and vein, the vein collapses on the screen
from left to right. The middle image has caught the vein collapse half way in its progress. The right image shows the entirety of the vein collapsed, arrowheads. This vein is
suitable for cannulation.
Not all cases of vascular access are for catheter placement and
some patients simply need to have blood drawn. However, in the
same difficult vascular access patients, multiple sticks are often
required to withdraw blood for laboratory use. The Sonic Window
has a role to play in such patients as well. Easily carried in a pocket,
rapidly activated and ideal for guiding a needle and visualizing it as
it enters a vein during venipuncture, the Sonic Window is a logical
phlebotomy tool. Similarly, arterial blood gases (ABGs) are often
complicated by body habitus, poor circulation and indistinguishable
pulses. The unique ability of the Sonic Window to easily identify
and stay over the radial artery makes it a potential tool for anyone
cannulating the radial artery for blood sampling. Literature support
for ultrasound guidance in radial artery cannulation has emerged
making it clear that arterial cannulation benefits from ultrasound
use.8,9 Using the Sonic Window for ABGs and arterial line placement
means knowing where your target is, despite the thready pulse,
and guiding the needle right to it.
By aligning the Sonic Window over the catheter in one view,
providers are able to check that the catheter is still in a good
position, as seen in Figure 5. Additionally, flushing the catheter
allows the operator to visualize a disturbance in the vein, just past
the tip of the catheter, again confirming an intra-vascular location.
Unlike performing the same task with a conventional B mode
ultrasound device, the Sonic Window requires considerably less
hand eye coordination. Using a conventional ultrasound machine
requires an in plane/long axis visualization, precisely holding the
transducer over the tip of the catheter and in the middle of the
vein. This can be challenging to novice ultrasound users. When
using the Sonic Window, the provider positions the device over the
vein and does not have to move or adjust any further. A gentle
flush with the other hand confirms catheter positioning.
8 Shiver S, Blaivas M, Lyon M. A prospective comparison of ultrasound-guided and blindly placed radial
arterial catheters. Acad Emerg Med. 2006 Dec;13(12):1275-9.
9 Schwemmer U, Arzet HA, Trautner H, Rauch S, Roewer N, Greim CA. Ultrasound-guided arterial
cannulation in infants improves success rate. Eur J Anaesthesiol. 2006 Jun;23(6):476-80.
Summary
Dynamic guidance for vascular access was an early point of care ultrasound application and it is now the standard of care for central line
placement. Despite 20 years of clinician use and experience, it is only recently that providers have widely recognized, and research has
proven, that ultrasound guidance for peripheral line placement decreases the rate of central line placement and therefore any associated
complications with the practice. The Sonic Window is specifically developed to simplify ultrasound guidance for vascular access with ease
of use, an ideal form factor, as well as utility for multiple vascular access applications.