The Angel Catheter in Trauma Patients – A Pilot Study

Whether early use of the Angel Catheter in trauma patients with pelvic, spine and lower limb injuries, with contraindications to pharmacological venous thromboembolism prophylaxis, is effective in preventing pulmonary embolism, feasible, and safe. The Pilot Study Protocol This is a prospective, single-arm, non-randomized interventional pilot study evaluating the feasibility and safety of the Angel® Catheter for prevention of pulmonary embolism. The study is funded by the National Trauma Research Institute at Bayside Health. The Angel Catheters will be purchased directly from the manufacturer – Mermaid Medical. • We will recruit 20 adult (age >18) patients with: - Major trauma with significant pelvic, lower limb or unstable spinal fractures - Contraindication for chemical VTE prophylaxis in the first 72 hours. - The Angel Catheter MUST be removed within 7 days (preferably within 3-4 days), and before patient full mobilization (see restrictions below). • Insertion will occur post a trauma chest, abdomen & pelvis CT scan (to exclude an IVC injury, assess anatomy, and measure insertion distance. - In rare cases, if required as part of resuscitative efforts, insertion of the catheter may need to be completed prior to CT scanning. Decision on this this will be based on type of injury (e.g. mangled lower limb with prolonged tourniquet time) and clinician assessment. • All patients will receive a CT Venogram prior to removal, for assessment of thrombus burden by Interventional Radiologists: - If thrombus occupies more than 20% of the volume of the filter component of the catheter, or if unable to start chemical VTE prophylaxis, removal will occur in the IR suite with prior insertion of a long-term IVC filter (through an Internal Jugular approach). • Wire-through-filter methods, to enable insertion of long-term IVC filters, will be avoided. • Partial withdrawal of the expanded filter to allow for placement of the traditional IVC filter may be considered by the Interventional Radiologist performing the procedure (using venography and fluoroscopy). - If thrombus occupies less than 20% of the volume of the filter component, and VTE prophylaxis can be commenced, removal of the catheter may occur at the bedside. - We acknowledge and accept some risk of clot disruption during removal of Angel catheters, similar to that of removal of indwelling central lines or longer-term IVC filters, but that this will likely be clinically asymptomatic • The protocol will be reviewed after the first 5 cases: - For consideration of the appropriate percentage of filter clot burden for catheter removal. - Any safety concerns or need for protocol amendment. Recruitment / Enrolment Participant presenting to the Alfred Trauma Services who meet the selection criteria will be screened sequentially for eligibility by the research team. Given the acute, life-threatening, and time-critical nature of inclusion criteria injuries, patients are anticipated to lack decision-making capacity required to provide prospective informed consent at time of enrolment. Therefore, a specific consenting procedure will be followed. Mobilisation restrictions while the Angel Catheter is in-situ: • Patients may move freely in bed. • Patients may sit out of bed at an angle of less than 90 degrees, similar to post–total hip replacement restrictions. • Patients may have toilet privileges but must not walk longer distances. • Repetitive hip flexion exercises must be avoided. • Agitation or delirium that prevents safe compliance with mobility restrictions is an indication for early removal. The Angel Catheter should be removed as soon as it is clinically safe to do so. Insertion The below instructions are in addition to the Bayside Health CVAD protocols: 1. Central Venous Access Device Insertion: Infection Prevention 2. Central Venous Access Device (CVAD) - PICC & CVCs: Access and Management Guideline 1. Only Trauma or Interventional Radiology Consultants who have been trained on the Angel Catheter will be involved in insertion and removal of the catheter. 2. A consent form signed by the patient or their Medical Treatment Decision Maker is required before insertion, except in rare cases where insertion is part of resuscitative efforts, when consent will be requested retrospectively. 3. Insertion will occur after performance of a trauma chest, abdomen & pelvis CT to: a. Estimate insertion distance b. Identify suspected iliac vein or IVC injuries c. Detect anatomical variances or anomalies such as: i. A short supra-renal IVC ii. May-Thurner anatomy d. In rare cases, if required as part of resuscitative efforts, insertion of the catheter may be completed prior to CT scanning (see above). 4. Insertion of the catheter will occur in-hours only (weekdays, 07:00-18:00), with the first 5 cases to be completed with Professors Goh or Clements present (IR representatives). Prepare the Angel® Catheter for insertion: 1. Prior to removing the catheter from package, flush each of the three lumens with 2-5ml of saline. Use the slide clamps to clamp the Proximal Sheath Port and Medial Filter Port. Leave the Distal Tip Port unclamped to allow for guidewire passage. 2. Collapse the expanded filter into the sheath by pinching the WHITE tabs on the proximal end of the catheter hub and pulling back on the TEAL coloured proximal hub until ‘STOP’ text can be seen and the WHITE tip of the catheter is seated in the outer sheath. a. Ensure that the filter has been collapsed prior to removal from packaging. Not doing so may result in damage to the catheter and/or filter. b. The proceduralist must be aware of potential air embolism associated with leaving open needles or catheters in central venous puncture sites or as a consequence of inadvertent disconnects. To lessen the risk of disconnects, only use securely tightened luer-lock connections with this device. Follow hospital protocol to guard against air embolism for all catheter maintenance. 3. Ensure complete wetting of the external surface of the catheter (with normal saline) to activate the hydrophilic coating. Insertion Technique: 1. Prepare area as for any central venous catheter with full aseptic technique (hat / gown / gloves / mask), and 70% red alcohol prep. 2. Use a procedure pack and large drapes to cover both lower limbs. 3. Aim for right femoral vein preferentially (to avoid May-Thurner anatomy). 4. Use local anesthetic as required. 5. Use an US probe with sterile sheath to locate the common femoral vein (CFV) and to confirm correct insertion. 6. Access the CFV using the 18G introducer needle and insert the guidewire as per the usual modified Seldinger technique. Note that the guidewire is longer than that of a quad lumen CVC. 7. Once guidewire placement in the CFV is confirmed on US, withdraw the needle and make a 3-5mm incision in the skin. 8. Dilate the access site with a 9F dilator over the guidewire, then remove the dilator from the access site. a. Failure to dilate the access site may lead to difficulties in the placement procedure that may result in damage to the catheter and/or filter. b. Do NOT use excessive force when advancing the dilator and ensure that the guidewire does not kink. 9. Pull on the WHITE hub to remove the Angel® Catheter from the packaging. 10. Advance the Angel® Catheter over the guidewire. a. Prior to insertion, ensure complete wetting of the external surface of the catheter (with normal saline) to activate the hydrophilic coating. b. Advance catheter all the way to the hub. c. Do NOT use excessive force when placing the Angel® Catheter. Filter Deployment: 1. Hold the TEAL hub stationary in one hand and retract the WHITE hub with the other hand to deploy the filter, ensuring that the hub is securely locked together. a. Do NOT use excessive force when deploying the filter. b. Do NOT torque or twist the device. i. Do NOT apply relative torque between the inner multi-lumen assembly and outer sheath assembly of the catheter. Application of relative torque between the inner multi-lumen assembly and outer sheath assembly of the catheter, while the filter is constrained, could cause the filter to twist about its central axis, possibly resulting in damage to the catheter and/or filter. ii. Do NOT apply torque to the inner multi-lumen assembly after deployment of the filter. Application of torque to the inner multi-lumen assembly, while the filter is deployed in the vena cava, could cause the filter to twist about its central axis, possibly resulting in damage to filter and/or damage or irritation to the lining of the vena cava. 2. Following placement of the Angel® Catheter, it is recommended to confirm proper position of the filter with an abdominal x-ray (AXR): a. The filter apex should be positioned in the region at or below L1. b. The filter base should be above L5. c. Note the indwelling catheter length per the centimetre mark closest to the access site, once initial satisfactory placement has been achieved, to ensure no unintentional catheter movement in subsequent catheter securement steps. 3. If adjustment of filter position is required for optimal placement: a. Collapse filter into the sheath by pinching the WHITE tabs on the proximal end of the catheter hub and pullback on the TEAL coloured hub until the BLACK band on the multi-lumen is visible, indicating that the filter is collapsed. The ‘STOP’ text indicates that the filter has been fully retrieved into the outer sheath. b. Relative to depth marker noted at time of initial AXR, adjust the catheter depth to obtain desired filter position in the inferior vena cava. c. Redeploy filter by holding the WHITE hub stationary while advancing the TEAL hub until the hub is locked together. d. Repeat AXR to confirm proper filter position. 4. Remove the guidewire. 5. After removing the guidewire, verify venous blood can be aspirated and flush each lumen. Engage the slide clamps after flushing to prevent blood loss. 6. Allowing space for proper positioning of a BIOPATCH® anti-infective dressing around the catheter at the access site, place the suture wing onto the catheter and lock it into position with the over-clamp. a. Ensure the catheter is dry prior to placement of the suture wing to provide secure grip between the catheter and the suture wing. The suture wing should be placed between the 24 cm mark and strain relief. Placement of the suture wing on the hydrophilic coating, at or below the 24 cm depth marker, may result in catheter slippage. 7. Suture the suture wing and over-clamp to the skin. 8. Place sutures through the loops of the catheter hub to reduce possibility of inadvertent decoupling of the catheter hub. a. Incorrect securement of the Angel® Catheter to the patient may result in movement of the filter within the vena cava. 9. Place recommended BIOPATCH anti-infective dressing around the catheter at the access site. 10. Apply Tegaderm™ dressing over access site and dress the access site per hospital protocol. a. After filter placement, any catheterization procedure requiring passage of a device through the filter is forbidden as it may be impeded and/or compromise filter integrity. 11. Record indwelling catheter length, per the centimetre mark closest to the access site, on the patient’s chart and the REDCap study form. Regular visual assessment of catheter position should be made to ensure that the catheter has not moved. a. Maintain access site regularly using aseptic technique per hospital protocol. b. Maintain catheter lumen per hospital protocol. It is recommended that catheter lumen be flushed a minimum of every 8-12 hours or have a continuous infusion to Keep Vein Open (KVO). 12. Clearly indicate on EMR, and with specific study label placed over the Tegaderm™ dressing, that patient has an IVC filter attached to a central venous catheter (Angel® Catheter). 13. Maintain the Angel® Catheter and access site per standard hospital protocols for central line catheters and guidelines for the prevention of intravascular catheter-related infections. 14. Fill REDCap study form. Removal 1. The Angel catheter will be removed within 3-4 days. Dwell-time must not exceed 7 days. 2. The Angel Catheter must be removed before patient full mobilization (see restrictions above). 3. The catheter will only be removed by a credentialled Trauma Service or Interventional Radiology Consultant. 4. All patients will receive a CT Venogram, using the white (proximal) lumen, prior to removal, for assessment of clot burden and catheter integrity. This will be reviewed by an Interventional Radiologist to assess clot burden and filter integrity. a. If clot occupies more than 20% of the volume of the filter component of the catheter, or if unable to start chemical VTE prophylaxis, removal will occur in the IR suite with insertion of a long-term IVC filter prior to removal of the Angel Catheter (using an Internal Jugular approach). i. Partial withdrawal of the expanded filter to allow for placement of the traditional IVC filter may be considered by the Interventional Radiologist performing the procedure, using venography and fluoroscopy. ii. Wire-through-filter methods, to enable insertion of long-term IVC filters, will be avoided. b. If clot occupies less than 20% of the volume of the filter component, and VTE prophylaxis can be commenced, removal of the catheter may occur at the bedside. 5. The acknowledgement and risk of clot disruption during removal of the Angel Catheter is required by the patient or person responsible (addressed in consent form). Filter Retrieval: 1. Once confirmed that the Angel® Catheter is safe to remove: a. Remove the suture wing and over-clamp from the catheter. b. Collapse the expanded filter into the sheath by pinching the WHITE tabs on the proximal end of the catheter hub and pulling back on the TEAL coloured proximal hub. The BLACK band on the multi-lumen indicates that the filter (without thrombus burden) has been collapsed. The ‘STOP’ text indicates that the filter has been fully retrieved into the outer sheath. i. Do NOT use excessive force when collapsing the filter into the outer sheath. Catheter Withdrawal: Do NOT completely withdraw the Angel® Catheter from the patient prior to collapsing the filter. 1. Grasping BOTH the inner catheter and WHITE outer sheath hub, withdraw the Angel® Catheter as one unit from the patient. a. Holding BOTH the inner catheter and WHITE outer sheath hub is important to prevent potential re-deployment of the filter during removal. 2. After withdrawal ensure that the entire Angel® Catheter has been withdrawn from the patient. a. Do NOT use excessive force when withdrawing the Angel® Catheter from the patient. b. Inspect the integrity of the catheter c. After use, the Angel® Catheter may be a potential biohazard. Handle and dispose of in accordance with hospital guidelines. MRI Compatibility The Angel® Catheter is MR Conditional. • A patient with the Angel Catheter in-situ can be safely scanned in an MR system meeting the following conditions: o Static magnetic field of 1.5 Tesla and 3 Tesla, with o Maximum spatial gradient magnetic field of 4,000 Gauss/cm (40 T/m); and o Maximum MR system reported, whole body averaged specific absorption rate (SAR) of 2 W/kg (Normal Operating Mode). • The Alfred MRI team anticipates being able to perform required MRIs on most participants, though some may require modifications to keep within allowed tolerances. • In rare cases, permitted tolerances may be exceeded (e.g. due to large body habitus) and an MRI may need to be aborted. o If a required MRI is delayed, or cannot be performed, every effort will be made to expedite safe removal of the Angel Catheter, so that patient care is not compromised. o This must be recorded in the study data form (REDCap). IV Contrast Injection • Both the proximal (white) and distal (brown) ports are pressure-rated for IV contrast injection. • The Alfred CT team have reviewed the catheter’s pressure ratings and are able to perform IV contrast injections as below. The permitted pressure ratings are: • Proximal Sheath Port (WHITE): 10mL/sec • Distal Tip Port (BROWN): 5mL/sec • Medial Filter Port (BLUE): DO NOT POWER INJECT • The Angel Catheter is rated for maximum of ten (10) power injections – note some trauma torso CT scans involve two boluses of IV contrast. Radiation Exposure • The study involves additional abdominal x-rays at time of insertion and a CT cavogram prior to removal of the Angel Catheter. • Where possible, attempts will be made to combine the CT cavogram with other planned CT scans to minimize radiation exposure and reduce ICU and CT workload. • The estimated excess radiation dose per patient is 10mSv. This radiation dose falls within Category IIb which represents a low level of risk (less than 1 in 1,000). • The anticipated benefit from the study is at least moderate and is directly aimed at prevention and treatment of pulmonary embolism, in high-risk severely injured trauma patients. • This is covered in the consent form. Data Analysis: The study is designed to assess feasibility, safety, and preliminary outcome signals, and is not powered for efficacy. The recruited participants will be analysed as one group, and although we will attempt to look at subgroups according to type of injury (as in inclusion criteria), this is unlikely to have the power needed to demonstrate significance.