Obtaining peripheral vascular access in medical patients is a necessary procedure for many
healthcare providers. Peripheral vascular access is traditionally performed using palpation
or visual inspection to identify appropriate points of entry in the vasculature after which
a needle and catheter are threaded through the skin and surround fascia into the vessel of
interest. This procedure, one of the most common procedures in the medical field including
both artery and vein access, is not 100% successfully attempted. Operator skill heavily
influences peripheral vascular cannulation. (Frisch et al. 2013) However, certain patient
populations have difficult peripheral vessels to identify by palpation or visual inspection
and past operators would be forced to perform the procedure blind based on anatomical
landmarks. Recently, to aid vascular identification and increase cannulation success, a
number of alternative techniques for peripheral vascular access have been described
Ultrasound-guided vascular access has been utilized in vascular access with improved success
rate. However, even with ultrasound guidance the first attempt success rate of cannulation
was only approximately 65%. A proposed failure of ultrasound guided peripheral vascular
access is most likely due to failure to advance the catheter into the vessel even the vessel
was successfully punctured. The investigators propose a specific technique and the positive
"Target Sign" as a means to obtain almost 100% successful peripheral vascular access.
The investigators plan to enroll 100 surgical patients in the above study and study
procedures will not differ from what a patient in the operating room under the care of
anesthesia faculty would receive. The above study is simply a way to identify the steps
regarding a specific technique.
The subjects (patients) will be brought to the Main Operating Room after their time in the
Day of Surgery Admissions (DOSA) at the discretion of the attending physicians and surgical
team. The patients will not be required to do anything different from standard anesthesia
and surgical practice at the hospital. Subjects will come to the operating room suite and
the usual monitors (electrocardiogram, non-invasive blood pressure, and oxygen saturation)
will be placed.
Prior to the routine induction of anesthesia, peripheral vascular access is usually
obtained. In regards to the subject population, peripheral vascular access is predicted to
be more difficult due to lack of visualization of the peripheral vessels. The skin will be
prepped with chlorhexidine, draped, and all subsequent procedures will be performed in
sterile fashion. The attending physician and/or resident will use the L25x Sonosite
transducer with the Sonosite Edge® (Washington, US) to identify a peripheral vessel in the
upper extremity for cannulation. After identification of the vessel, the operator will line
the L25x Sonosite transducer to place the vessel horizontally midline on the Sonosite Edge®
screen to give the most available viewing area. A BD Insyte® Autoguard® 16G shielded IV
catheter (Becton Dickinson Infusion Therapy Systems Inc., Utah, US) will be advanced toward
the vessel at an approximately 10˚ angle. Once the needle tip is identified on the Sonosite
Edge® monitor in short axis view, the following steps will ensue:
1. Advance the needle toward the vessel slowly, adjusting the ultrasound transducer
position and angle to continue to keep the needle tip and vessel identified on the
Sonosite Edge® monitor.
2. Puncture the anterior wall of the vessel with the needle tip
3. Confirm needle tip placement in vessel
4. Advance the needle within the vessel 5mm under continuous visualization
5. View and record confirmation of "Target Sign" on ultrasound monitor
1. Positive Target Sign=needle tip is identified on ultrasound monitor within vessel
and is able to move freely within the vessel, similar to a circle with a target in
the middle which is able to move. This confirms the needle is unrestricted in the
2. Negative Target Sign=needle is identified on ultrasound monitor within vessel, but
is unable to move freely within the vessel without dragging the vessel wall with
needle movement. This confirms the needle is transfixed on the posterior wall of
6. Thread the catheter over the needle.
7. At this point, the catheter could be advanced either with or without a guidewire at the
operator's discretion Members of the research team will be available for verbal
assistance throughout this procedure.
Number of attempts and time to successful vessel cannulation will be measured, starting from
when either the operator's fingers or the ultrasound probe made contact with the patient's
skin. Successful vessel cannulation will be defined as a flowing IV bag of saline after
connection and confirmation of flow via fluid agitation in vessel identified via ultrasound.
This procedure will be incorporated in the subjects standard of care and will not extend the
time of operation.
At this point, patient participation in the study will be over and surgical operation under
the discretion of the surgical team. The video recording of the Target Sign will be saved
and given to a member of the research team unknowing of the success of the cannulation. The
member of the research team will decide, based on the ultrasound video recording of a
positive or negative Target Sign, if the cannulation was successful or unsuccessful. The
viewer will record his/her answers and compare with the actual result of the cannulation.
Analysis of unsuccessful and successful cannulations will be compared with a Positive or
Negative Target Sign. No additional long-term followup will occur.
1. morbid obese surgical patients requiring large bore IV.
2. no visible intravenous access in upper arm