Intravascular Injection: Must know tip!
The available reports suggest that ultrasound guidance may reduce but not eliminate complications during nerve blocks, such as intraneural or intravascular injections. Accidental intravascular injections of local anesthetic during nerve blocks can still occur, as was the case in this report of local anesthetic systemic toxicity (LAST) during an infraclavicular brachial plexus block. Of note, the intravascular injection occurred despite the use of ultrasound guidance and the fact that aspiration for blood was negative.
Some clinicians add epinephrine as a vascular marker to reduce the risk of intravascular injections during regional anesthesia, although the usefulness of epinephrine for this indication has been challenged. Ideally, an IV injection of epinephrine-containing local anesthetic will result in tachycardia and an increase in blood pressure. If the injections are given in small increments while intermittently aspirating and evaluating vital signs, it may be possible to detect an intravascular injection BEFORE the administration of the entire planned dose of LA.
However, during the performance of nerve blocks, the operator is often busy monitoring the ultrasound screen, the patient, and the vital signs, forgetting to check the tip of the needle hub for blood, while it is exactly here where the first indication of an intravascular needle placement can be detected. At the same time, the helper person expects to see the blood in the syringe, which never happens. Unless the helping person observes the injection tubing at the needle hub, they can easily miss an intravascular needle placement.
One of the important teaching points in NYSORA’s education on regional anesthesia and pain medicine is to hold the needle so that the hub of the injection tubing can be seen at all times. The operator should pay attention each time they command for aspiration to be done that the needle hub is clear.
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Until next time!
