Double Injection Technique Provides Quicker Onset of Surgical Anaesthesia

Double injection ultrasound-guided supraclavicular block seem to provide quicker onset of surgical anaesthesia and longer postoperative analgesia than the single-injection technique in patients undergoing upper limb orthopaedic surgery, researchers reported here at the 2018 Annual Meeting of the American Society of Anesthesiologists (ASA).

The researchers presented results from a prospective, randomized study led by Babita Gupta, MD, All India Institute of Medical Sciences, Gurgaon, India.

Although ultrasound-guided supraclavicular block has a good success rate, it remains unclear whether multiple injections are better than a single injection. A previous randomised, double-bling study comparing the single and triple injection techniques found that although the performance time of the single-injection technique was shorter, triple injection had a faster onset and resulted in a more successful block of all nerves in the first 20 minutes.

For the current study, Dr. Gupta and colleagues randomised 50 patients to receive a single or double injection for ultrasound-guided supraclavicular block. The local anaesthetic drug (bupivacaine 0.5%) and total volume (20 mL) were identical in all subjects.

In the single-injection group, the whole volume (20 mL) was injected in the corner pocket (intersection of the first rib and subclavian artery). In the double injection group, half the volume (10 mL) was injected inside the main neural cluster and the remaining half (10 mL) in the corner pocket.

The onset time of surgical anaesthesia was shorter with the double-injection technique (12.83 minutes vs 17.73 minutes; P = .001). The performance times in both the groups were comparable: 163.4 seconds for double injection vs 172.08 seconds for single injection.

In addition, the total duration of analgesia was significantly longer in the double-injection group (12.75 hours vs 9.76 hours; P = .002).

There was one surgical anaesthesia failure in the double injection group and 3 failures in the single injection group.