RAPTIR (Retroclavicular APproach to The Infraclavicular Region)
a potent single-injection upper extremity block that provides extensive, reliable arm anesthesia
- An infraclavicular brachial plexus block with improved needle visualization versus the traditional infraclavicular technique.
- In the clip below, the needle has been passed behind the clavicle and is positioned just deep to the axillary artery. Injection of local anesthetic easily distends the fascial compartment (axillary sheath) and anesthetizes the posterior, lateral, and medial cords of the brachial plexus.
What we love about the RAPTIR:
- extensive, reliable upper extremity anesthesia
- safety - decreased risk of phrenic nerve paralysis, excellent needle visualization when near axillary artery at injection target
- easily identified sonographic landmarks
- not dependent on pt holding neck very still during needling such as with blocks in the neck (e.g. interscalene)
- rapid performance - needling time typically less than 5 minutes
- minimal patient discomfort during needling
- comfortable patient positioning
RAPTIR is GREAT for:
- fracture & dislocation reductions (follow these guidelines)
- extensive upper extremity soft tissue injuries (e.g. large/complex wounds requiring debridement, exploration, repair)
- large arm abscesses (e.g. deltoid or forearm abscesses in setting of IDU)
- pain control (e.g. fireworks/blast injuries, traumatic amputations, etc.)
RAPTIR is NOT great for:
- pt’s with a deformed clavicle (such as from a prior or acute clavicle fracture), thick pectoral region, “full” supraclavicular fossa, or short neck
Since the ultrasound beam cannot penetrate the clavicle, the RAPTIR block needle initially passes through an approximately 3cm “blind zone” before emerging from the clavicle’s acoustic shadow and becoming visible on ultrasound in the infraclavicular space. This presents the novel experience of passing a needle behind a bone while performing a regional block. To safely transverse this “blind zone,” the transducer is positioned lateral to the thoracic cage and aimed towards the axilla (as described in the sections below), then the advancing needle is simply aligned with the long axis of the ultrasound beam. By staying close to the underside of the clavicle and advancing at an angle parallel to the surface of the gurney bed, the block needle passes safely through muscle and loose connective tissue.
How it's done:
Place the patient in a semi-recumbent supine position with the affected extremity adducted at their side in a position of comfort. Rotate the patients head away from the injured limb. Place a folded towel under the ipsilateral shoulder. Stand at the head of the bed with the ultrasound system in direct line-of-sight on the side of injury.
Place a high-frequency linear transducer in parasagittal orientation over the medial portion of the clavicle with the transducer marker facing cephalad (Figure 1A).
Slide the transducer laterally along the clavicle to the deltopectoral groove, then rotate the transducer slightly so that it aims towards the axilla (Figure 1B).
While sliding laterally, sonographically visualize the axillary artery in cross section as it emerges from under the clavicle (Figure 1C), traverses the 2nd rib, then courses away from the thoracic cage (Figure 1D).
The extrathoracic portion of the axillary artery will be apparent on ultrasound when the 2nd rib drops out of view. At this location, identify the injection target which lies just posterior to the axillary artery.
Keeping the transducer fixed over the injection target and aimed at the axilla, identify a block needle insertion site aligned with the long axis of the ultrasound beam and approximately 2 cm cephalad to the clavicle (Figure 2). This will ensure a safe needle path and allow adequate room for the needle to clear the posterior surface of the clavicle without angling posteriorly. Place a LA skin wheal at the insertion site using a 25-27g needle, then insert a block needle (e.g. Tuohy 20g 90mm epidural needle) through the skin wheal and advance the needle beneath the clavicle towards the ultrasound beam at angle parallel to the gurney bed. When passing through the “blind zone” created by the clavicle, the needle should never be angled posteriorly as this increases the risk of pneumothorax. After insertion through the approximately 3cm “blind zone" stop further needle advance and make slight transducer and needle adjustments until the needle tip is seen emerging from beneath the clavicle (Figure 3A). Continue advancing with in-plane ultrasound guidance toward the target location just posterior to the axillary artery. Here, the operator may feel a slight “fascial click” theorized to correspond with penetration of a fascial septum within the axillary sheath. Aspirate to check for inadvertent vascular puncture, and then inject small aliquots of LA. Anechoic anesthetic fluid should be seen spreading just posterior to the axillary artery, confirming needle tip location within the sheath (Figure 3B). Once satisfied with the needle position, gradually inject LA until a total of 35-40 mLs is deposited within the sheath (e.g. for 70kg pt: 35-40 mLs of 2% chloroprocaine, 1% lidocaine with epineperine, or 0.5% ropivacaine. always adhere to weight-based LA dosing guidelines). In our experience, total needling time is usually less than 5 minutes and dense arm anesthesia develops within 30 minutes.
Patient, operator and ultrasound system positioning. Note needle visible on screen from across the room. Plus AWESOME SOCKS
relationship of transducer and needle insertion point to clavicle and 2nd rib (dashed lines), brachial plexus (yellow), axillary artery (red)
Needle visibility in the traditional approach ICB (TICB) vs the RAPTIR
Most tissues in the human body have irregular surfaces and act as radiating reflectors reflecting ultrasound beams in many directions. In contrast, needles have machined smooth and straight surfaces that act as specular (mirror-like) reflectors reflecting nearly the entire ultrasound beam at an angle directly opposite its angle of incidence upon the needle.
Top & middle left: Needle and transducer positions for the Traditional ICB.
Top & middle right: Needle and transducer positions for the RAPTIR.
Bottom left: Ultrasound view of the needle in the TICB. At this needle trajectory, the ultrasound beam is reflected off the mirror-like surface of the needle away from the transducer making the needle shaft and tip nearly invisible. (C = cross section of clavicle at insertion point)
Bottom right: A similar ultrasound view of the needle in the RAPTIR. The needle trajectory is now parallel to the transducer and the beam reflects straight back to the transducer resulting in an intensely hyperechoic needle shaft and tip.
A Tuohy 20g 90mm epidural needle is used as the block needle in both images.