Antegrade Versus Retrograde IV for Blood Draws

Comparison of Retrograde and Antegrade Peripheral Intravenous Cannulation on the Ability to Aspirate Blood Samples in the Operating Room

The purpose of this study is to compare success rates of antegrade and retrograde intravenous (IV) catheters in their ability to aspirate 20 milliliter blood sample within a 2 minute time frame, 3 hours after initial insertion. Antegrade IV catheters are placed identically to conventional IV catheters, with the end of the catheter pointed toward the direction of blood flow to the heart. Retrograde catheters are placed "backwards" with the end of the catheter pointed away from the direction of venous blood flow. The hypothesis is that retrograde IVs will have a significantly higher success rate of blood draw at the 3 hour time mark without use of a proximal tourniquet.

1. Patients scheduled for surgery under general anesthesia at the University of Iowa Hospitals and Clinics (UIHC) will be recruited pre-operatively in the Day of Surgery Admissions (DoSA) rooms before their surgery takes place. Once the subject is recruited and has signed a consent form, they will be randomized to either retrograde or antegrade IV. Once in the operating room and general anesthesia has been induced, a 20 gauge 30 millimeter catheter will be placed in a vein of one of the upper extremities by an anesthesiologist member of the research team. A drape will obscure viewing of the procedure by the clinical anesthesia provider. They will then connect the catheter to an IV tubing set and cover the insertion site with a opaque towel, so as to blind the anesthesia provider caring for the patient in the OR.
2. 0.9% normal saline (NS) will be infused at a rate of 20 milliliters (mL) per hour to keep it open (TKO) and it will not be used for drug infusion.
3. Three hours after insertion, the anesthesia provider in the OR will attempt a blood draw from a stopcock 33 inches from the catheter. A successful 20 mL blood draw must be achieved within 2 minutes after attempt is started or it will be defined as a failed attempt. If blood draw fails, an upper arm tourniquet will be placed and the blood draw will be reattempted following the same guidelines as the initial attempt. After every blood draw, 10 mL of NS will be flushed back through the IV.
4. At the end of surgery, within 30 minutes of extubation, the anesthesia provider in the OR will attempt a blood draw from a stopcock 33 inches from the catheter. A successful 20 mL blood draw must be achieved within 2 minutes after attempt is started or it will be defined as a failed attempt. If blood draw fails, an upper arm tourniquet will be placed and the blood draw will be reattempted following the same guidelines as the initial attempt. After every successful blood draw 10 mL of NS will be flushed back through the IV.
5. The IV will be saline locked at the end of the case.
6. The IV will be removed within 15 minutes upon arrival in the Post Anesthesia Care Unit (PACU) by the same anesthesiologist member of the research team who placed it and the site will be dressed appropriately.
7. Follow up will happen on post-operative Day 1 (POD1) either in person if the patient is admitted to a UIHC inpatient unit or via a phone call if they are discharged before POD1. At this POD1 check, the patient will be asked about the prior IV site: level of pain, if there is a hematoma, or possible infection. There will be a maximum of 3 attempts to contact the subject. This data will be gathered by a research coordinator member of the research team who is unaware of which study arm the subject was randomized to.
8. A second follow up will happen on 14 days after the surgery/IV placement via a phone call. Again, the patient will be asked about the prior IV site: level of pain, if there is a hematoma, or possible infection. There will be a maximum of 3 attempts to contact the subject. This data will be gathered by a research coordinator member of the research team who is unaware of which study arm the subject was randomized to.

Inclusion Criteria:

• Adult patients
• English speaking
• Age 18-90
• Scheduled to undergo surgery under general anesthesia at the University of Iowa Hospitals and Clinics
• Surgery is scheduled to last at least 3 hours

Exclusion Criteria:

• Emergency surgery
• Previous or planned sentinel node dissection on ipsilateral arm of study IV
• Existing or planned arteriovenous fistula on ipsilateral arm of study IV
• Surgery with lateral positioning
• Surgery which involves tucking the arm with study IV
• Any additional peripheral IV catheters distal to study IV
• Non invasive blood pressure cuff placed on arm with study IV