Longitudinal or Transverse Orientation of Ultrasound Probe in Minimally Invasive Venous Surgery.

Study Overview
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Brief Summary
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Longitudinal ultrasound orientation during central venous cannulation has been suggested by a number of radomised studies to offer superior cannulation rates. This technique may offer a simple, safe and cost-neutral step to improve cannulation rates in the widely performed minimally invasive endovenous intervention.

Detailed Description
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Varicose veins are an extremely common disorder and negatively impact on patient quality of life. In recent years minimally invasive venous treatments for varicose veins (MIVT) have emerged as an effective alternative to open surgery. It is associated with a reduction in peri-operative morbidity, recovery time and increased quality of life scores when compared with open surgical stripping4. Furthermore, MIVT is now widely carried out under local anaesthesia. Typically, MIVT requires cannulation, under ultrasound guidance, of either the great or small saphenous vein in the lower extremity to allow subsequent passage of a venous catheter. This cannulation technique is widely used for venous and arterial cannulation throughout the body. It entails utilising an ultrasound probe in either a longitudinal or transverse orientation (to the target vein) to guide an entry needle into a target vessel. The longitudinal orientation, while unstable, offers better visualisation of the vein when performed accurately. Conversely, the transverse approach is very stable with poorer visualisation of the target vessel. As such, no definitve guidance is available to guide treating physicians as to the optimal orientation with a wide variation among practitioners. The cannulation process for MIVT is often further challenged by both the small calibre and tendency toward vasospasm of target veins. Failure of cannulation may result in greater rates of conversion to open surgery exposing the patient to the the higher rate of morbidity associated with open surgery. More importantly, repeated cannulation results in significant discomfort and hence a reduction in patient satisfaction. Longitudinal ultrasound orientation during venous cannulation has been suggested by a number of radomised studies to offer superior cannulation rates of cannulation. This technique may offer a simple, safe and cost-neutral step to improve cannulation rates in the widely performed MIVT. The authors propose a blinded randomized controlled study to investigate the effects of ultrasound orietation on cannulation rates in MIVT. To test this hypothesis we plan to randomise 100 patients undergoing MIVT to either venous cannulation with transverse or longitudinal orientation of the ultrasound probe.

Official Title
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Does Longitudinal or Transverse Orientation of Ultrasound Probe Improve Cannulation Success in Minimally Invasive Venous Surgery. A Randomized Controlled Trial.

Conditions
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Varicose Veins, Endovenous Procedures, Venous Access

Intervention / Treatment
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* Diagnostic Test: Longitudinal
* Diagnostic Test: Transverse


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: For minimally invasive venous surgery of the lower limb (Clinical-Etiology-Anatomy-Pathophysiology (CEAP) classification score 2 of greater) Intervention requiring venous cannulation of axial lower limb vein Full consent >18 years No concomitant deep venous incompetence Exclusion Criteria: General anaesthesia

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Parallell block randomised groups
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Transverse Ultrasound Orientation<br>Transverse placement of ultrasound to long axis of target lower limb vein | Diagnostic Test: Transverse<br>* Transverse orientation of ultrasound to long axis of vein to guide access needle<br>|
| Experimental: Longitudinal Ultrasound Orientation<br>Longitudinal placement of ultrasound to long axis of target lower limb vein | Diagnostic Test: Longitudinal<br>* Longitudinal orientation of ultrasound to long axis of vein to guide access needle<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall successful Cannulation rate as a percentage | Overall successful cannulation of the target axial lower limb vein for endovenous treatment. Successful cannulation will be defined as intraluminal placement of the access cannula in the targeted axial vein. | Immediate | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time in seconds to cannulation | Time from skin puncture to successful placement of access catheter in the target vein | Immediate | 
| Number of cannulation attempts | Number of times the skin is pierced in an attempt to cannulate the target vein | Immediate | 
| Peri-cannulation pain | Pain will be measured using a visual analogue scale of 0-100 | Immediate |