From the Guidelines
The most common reason for unsuccessful subclavian line placement is anatomical variation leading to difficulty in accessing the subclavian vein, which can be mitigated by using ultrasound guidance as recommended by recent guidelines 1. This typically manifests as an inability to locate or cannulate the vein despite proper positioning and technique. Patient factors that contribute to this challenge include:
- Obesity
- Dehydration
- Hypovolemia
- Previous vascular injury or thrombosis at the insertion site Technical factors also play a significant role, particularly inadequate positioning of the patient. The optimal position involves placing a rolled towel between the shoulder blades to create a slight extension of the neck and retraction of the shoulders, which helps to make the anatomical landmarks more prominent. Operator inexperience is another major contributor to unsuccessful placement, as the subclavian approach requires significant technical skill and understanding of the relevant anatomy. Using ultrasound guidance can significantly improve success rates by allowing direct visualization of the vein and surrounding structures, helping to avoid arterial puncture and pneumothorax, which are serious complications of this procedure, as supported by guidelines from medical societies 1. However, it's worth noting that while ultrasound guidance offers clear gains in safety and quality for internal jugular vein placement, its benefits for subclavian vein placement are smaller, but still recommended for improving outcomes 1.
From the Research
Unsuccessful Subclavian Line Placement
The most common reasons for unsuccessful subclavian line placement include:
- Improper site for needle insertion relative to the clavicle
- Insertion of the needle through the clavicular periosteum
- Too shallow of a trajectory for the needle
- Improper or inadequate anatomic landmark identification
- Aiming the needle too cephalad
- Inadvertent movement of the needle out of the vein before or during wire placement 2 Other factors associated with failed attempts include:
- Prior major surgery in the region
- A body-mass index higher than 30 or lower than 20
- Previous catheterization 3 Additionally, the number of needle passes is strongly associated with the rates of failure and complications, with the complication rate rising from 4.3 percent with one pass to 24.0 percent with more than two passes 3