emDOCs Podcast – Episode 28: Difficult Vascular Access
- May 11th, 2021
- Brit Long
Today on the emDOCs cast with Brit Long, MD (@long_brit), we cover difficult vascular access in the hemodynamically unstable and stable patient.
Difficult Vascular Access
Obtaining peripheral intravascular (IV) access is a common procedure in the Emergency Department and an essential aspect of managing critically ill patients.
IV access may be challenging in up to up to 30% of patients.
Factors associated with DVA include obesity, diabetes, and IV drug use, among others.
The Crashing Patient
Large bore peripheral IVs (14-16 gauge) achieve flow rates significantly higher than that of triple lumen central venous catheters (TLC), as evidenced in the table below. Also ensure use of a pressure bag.
In general, any critical patient should receive two sites of peripheral access in case one line fails. If peripheral IVs are not easily obtainable, place an intraosseous (IO) catheters in the unstable patient.
IO catheters can be placed successfully in about 4 seconds. During cardiac arrest, IO placement has higher success rates and faster placement than central lines. Any fluid, blood product, or medication that can be infused through an IV catheter can also be infused through an IO.
While placement of the IO itself is generally well-tolerated, the process of medication and fluid administration is notably painful. In awake patients, infusing lidocaine prior to fluid or other drug administration can significantly decrease pain from infusion.
The Stable Patient
There are several other options to consider for vascular access in the stable patient. First, consider whether IV access is necessary! If you only need labs, consider a straight stick.
Consider what you need the line for. Most facilities require lower gauge catheters (18-20 gauge or lower) and proximal (antecubital fossa or above) IVs for contrast-enhanced CT studies. Image quality is directly affected by flow rate through catheters, and adequate flow rates are far less likely to be achieved in smaller bore catheters in veins distal to the antecubital fossa.
Landmark-based PIV placement is a skill with which every emergency physician should have some familiarity. While some would think a discussion of patients with DVA would preclude landmark-based techniques, one study found that of patients reporting requiring “multiple IV attempts” in the past, only 14% required more than three attempts or a rescue technique (ultrasound-guided IV or external jugular vein IV).
Prior to attempting PIV insertion, see if your ancillary staff had tried a smaller gauge needle. Gentle fluid hydration and many medications can be administered through a 22-gauge catheter, so a patient with multiple failed attempts at cannulation with an 18 or 20-gauge needle can often be rescued by switching to a smaller bore catheter.
Several adjuncts meant to increase vein diameter can be used to increase the chance of success if nursing or EMS have difficulty (some also apply to the US-guided technique):
- Use gravity to your advantage by placing the target vessel below the level of the heart
- Apply a tourniquet
- Have the patient “pump” their fist by clenching and relaxing it
- Light tapping of the vein can induce venodilation via an unknown mechanism
- “Milking” the vein proximal to distal can increase vein diameter
- Application of warmth increases venodilation, decreases time to cannulation, and increases first pass success
- If no heat packs are available, placing the patient’s hand in a disposable glove might do the trick
- Several studies have shown application of nitroglycerin ointment to increase vein diameter and lead to increased successful placement
A Forgotten Vein: The EJ
Once landmark-based attempts have been unsuccessful, before reaching for an ultrasound, consider the external jugular vein.
Place the patient in Trendelenburg position and have them rotate their head away from the target vessel. While standing at the head of the bed, use your left thumb to provide traction and your index finger to compress the vein proximally. Cannulate midway between the angle of the jaw and the clavicle. Having the patient perform a Valsalva maneuver can also further distend the vessel.
The Ultrasound-Guided IV
Ultrasound-guided IV placement has been shown to be highly successful, however failure rates can be as high as 45-56%, compared to 19-25% of landmark-placed IVs. Here are some pointers:
- Always start distally and work your way proximally until you find an adequate vessel
- Look for veins that are superficial and wide; one study demonstrated an odds ratio of 1.79 for increased successful cannulation with each 1 mm increase in vessel diameter, and no vessels were successfully cannulated beyond a depth of 1.6 cm
- Utilize a longer catheter (ideally > 2.5 inches) to increase the lifespan of the IV
- Failure of the IV is high when <30% of the catheter length is in the vessel and minimized when >65% of the catheter is intravascular
- After obtaining the “flash” upon entry into the vessel, try to advance the needle as far into the vessel as possible before advancing the catheter over the needle
- While advancing the needle in the vein, maintain your probe position at the tip in order to avoid “back-walling” through the vessel, increasing the risk of extravasation and catheter failure
One final note: while there is limited evidence that probe covers and adhesive barriers limit infection, the American College of Emergency Physicians recommends the use of such barriers, and compliance with such recommendations is as low as 22% in one study.
The “Easy IJ”
The “Easy IJ” involves placing an extra-long 18-gauge single-lumen catheter (those typically used for US-guided IVs) in the internal jugular vein. In one study in the emergency setting among patients who had failed traditional ultrasound-guided PIV placement, this technique was successful 88% of the time. There was no incidence of line infection, arterial puncture, or pneumothorax, and the only complication was loss of catheter patency in 14% of patients. Insertion time was approximately 5 minutes on average. These lines were placed using the same level of sterile technique as ultrasound-guided peripheral IVs, therefore saving time and resources as compared to CVC placement. It should be noted that this study recommended a 24-hour limit on use of the line given concern for infection since it was placed in a central vein.
One Last Point
Midline catheters are ab alternative to placing ultrasound-guided IVs and central lines. One observational study of 403 ED patients showed this technique to be successful 99% of the time with a median number of 1 attempt. Severe complications only occurred in 3 patients (1 arterial puncture and 2 vesicant extravasations) and no line-associated bloodstream infections or deep vein thromboses were observed. Vasopressors were also safely administered through these lines in 29.5% of patients.
- When a patient is in extremis and PIVs are not easily obtainable, don’t hesitate to place an IO
- Utilize a pressure bag with any form of intravascular access to increase flow rates
- Blood aspirated from an IO can be used for laboratory analysis, although not all values will be accurate
- If using the landmark-approach, use adjunctive techniques to increase rates of success
- Consider the external jugular vein before jumping to ultrasound-guided PIV
- When placing an ultrasound guided IV, vessels that are more superficial and wider in diameter will lead to increased successful placement
- Longer catheters with the majority of the catheter in the vessel lead to increased lifespan of ultrasound-guided IVs
- If ultrasound-guided peripheral IV placement isn’t successful, consider an “easy-IJ” before placing a CVC
- Midline catheter placement is an emerging alternative to both ultrasound-guided IVs and CVCs