Central Venous Access Procedures

Peripheral Intravenous Cannulation

Patients in the cardiac intensive care unit (CICU) require reliable intravenous access. Dependable peripheral vein cannulation technique is an essential tool to establish intravenous access in critically ill patients.

Technique

Although any vein may be utilized for emergency access, distal upper extremity veins and superficial jugular veins are prime peripheral cannulation targets. Note that highly mobile sites may limit reliability following insertion. For example, cannulation at the antecubital fossa requires the arm to maintain a straight position. When present, Y-shaped venous confluences are preferred targets. The dorsal hand, wrist, and forearm are common access sites. Use of a proximal tourniquet or blood pressure cuff accentuates the venous targets. Avoid tying the tourniquet in a tight knot. Focused manual pressure may be applied to distend a superficial jugular vein. Actively pumping the fist hastens venous engorgement at upper extremity sites.

Steps for inserting a peripheral intravenous line are shown in Fig. 42.1 . Always wear clean gloves. When targeting a venous Y-confluence, aim for the branch point. Local anesthesia may be infiltrated prior to cannulation but is not required. Apply traction with the nondominant hand to anchor the vein and keep the skin taut. Advance the catheter-over-needle assembly through the skin and into the vein while monitoring for a blood flash at the needle hub. The initial flash represents needle-tip penetration. Advance 1 to 2 mm to ensure that the entire needle tip is within the vessel before advancing the catheter into the vein. Maintain the needle in position and release the tourniquet. Next, remove the needle and discard it. Connect the intravenous connector tubing and secure the catheter. Monitor for subcutaneous infiltration while gently flushing the catheter with sterile crystalloid.

Central Venous Access General Principles and Preparation

Central venous access is indicated in CICU patients who require reliable intravenous access, vasopressor administration, hemodynamic monitoring, temporary transvenous pacing, and hemodialysis access. Contraindications to central access are relative, depending on alternative vascular access options and the urgency of the situation. Anatomic distortion, local infection, and existing hardware justify avoiding specific sites when possible. Coagulopathy is not a contraindication to central access placement, but the procedural risk and patient benefits should be carefully weighed.

Central access is often required emergently and obtaining consent may not be practical. In nonemergent circumstances, consent should be obtained prior to cannulation and should highlight the benefits and risks of the procedure. Infection, bleeding, arterial injury, venous thrombosis, and pneumothorax are all important risks to discuss. After consent is obtained, dedicate several minutes to optimal site selection and preparation.

Most nonemergent central venous catheters in the CICU are placed in the internal jugular or subclavian vein. If ultrasound is available, the site should be investigated prior to skin preparation and draping. Abnormal vascular anatomy or visible clots may prohibit a preferred site. The Trendelenburg position is recommended for subclavian and jugular access if the patient can safely tolerate repositioning. A patient in severe respiratory distress may require intubation prior to obtaining central access. The neutral body position is ideal for most central lines with a few modifications. Patients may need to have breast tissue or an abdominal pannus retracted by an assistant or secured with tape to access a site.

Once the site is selected and the patient is positioned, the skin should be cleaned. Chlorhexidine-based solutions reduce central line–associated blood stream infection (CLABSI) compared with povidone iodine-alcohol solutions. Full sterile precautions consisting of hat, face mask, eye shield, sterile gown, sterile gloves, and large sterile drape should be used for all central access procedures. A table large enough to accommodate the central line kit should be ergonomically positioned within the provider's arm reach. Supplies should not be placed on the sterile drape as patients can unexpectedly move during the procedure. The insertion site should be anesthetized with 1% lidocaine. Ultrasound guidance is recommended for access procedures when available. It may be used to confirm appropriate anatomy and landmarks prior to instrumentation or provide dynamic real-time imaging to track needle penetration.

Seldinger Technique

The modified Seldinger guidewire technique is standard for central venous and arterial access procedures. Initial vessel puncture is obtained with a large-bore, 18-gauge introducer needle or catheter-over-needle assembly. Needle trajectory and depth should be monitored closely throughout the procedure. Continuous negative pressure is applied to the aspirating syringe during needle advancement and withdrawal. Initial blood flash may be first recognized during needle withdrawal. The ability to continuously aspirate while maintaining strict control of the needle requires practice. Novice providers should be closely supervised. Venous puncture confirmation is important for central venous access procedures to avoid inadvertent arterial cannulation. Blood color, pulsatility, and ultrasound visualization may be misleading in certain circumstances. A 30-cm length of intravenous or pressure tubing can be used to gauge or transduce pressure prior to vessel dilation. The pressure tubing may be connected directly to the introducer needle or angiocath inserted over the needle or via guidewire.

The guidewire is next advanced through the introducer needle to approximately 20 cm. The needle must remain stationary before the wire is inserted. Bracing the hand against the patient to steady the needle and avoid accidental needle movement is a common technique. The guidewire should pass easily with minimal resistance. If resistance is encountered, remove the wire, reconfirm blood aspiration, or reposition the needle trajectory or guidewire J-tip orientation prior to readvancing the guidewire. With the wire stabilized at 20 cm, the needle is removed and a small stab incision at the guidewire exit site is completed with a No. 11 scalpel. While stabilizing the guidewire, the tissue tract dilator is advanced over the guidewire through the skin and connective tissue to reach the vessel. Care must be taken to avoid advancing the wire and dilator together, as this can bend the wire and damage the vessel. The wire should always slide easily within the dilator during proper technique. Next, the dilator is removed while keeping the wire stationary and maintaining hemostasis at the site with firm pressure. The vascular catheter is then advanced into position over the guidewire using the same technique. Finally, the guidewire is removed, the catheter lumens are flushed, and the catheter is secured to the skin at the appropriate depth (usually 15 to 20 cm depending on access site and patient size).

Internal Jugular Vein