Ultrasound guidance is rapidly becoming the gold standard for regional anesthesia.
There is an ever growing weight of evidence, matched with improving technology, to show that the use of ultrasound has significant benefits over conventional techniques, such as nerve stimulation and loss of resistance. The improved safety and efficacy that ultrasound brings to regional anesthesia will help promote its use and realize the benefits that regional anesthesia has over general anesthesia, such as decreased morbidity and mortality, superior postoperative analgesia, cost-effectiveness, decreased postoperative complications and an improved postoperative.
The use of ultrasound imaging techniques in regional anesthesia is rapidly becoming an area of increasing interest. It represents one of the largest changes that the field of regional anesthesia has seen. For the first time, the operator is able to view an image of the target nerve directly, guide the needle under real-time observation, navigate away from sensitive anatomy, and monitor the spread of local anesthetic (LA).
This comes at a time when an ageing population presents with an increasing range of comorbidities, thereby demanding a wider choice of surgical and anesthetic options to ensure optimal clinical care and a decreased risk of complications. The key to successful regional anesthesia is deposition of LA accurately around the nerve structures.
If the use of ultrasound is to become more widespread amongst anesthetists, then it must be shown to be clinically effective, practical and cost-effective. The use of ultrasound guidance in daily clinical practice requires a degree of training and an understanding of the equipment and technology.
The single most important advantage that ultrasound brings to regional anesthesia is the ability to confirm the exact placement and spread of LA; it is the LA that blocks the nerve and not the needle. The needle can be manipulated under real-time observation to the target nerve, and LA placed directly around the nerve, resulting in a faster onset, longer duration and improved quality block using less LA. Hazardous structures such as blood vessels, pleural and viscera can be avoided, and complications can thereby be minimized. Ultrasound frees the operator from using the classically described landmarks. Nerves can be targeted at any point along their course where they can be seen.
Blind techniques’ relying on pops, clicks, twitches and the need for multiple trial and error needle passes, with their lack of accuracy, reliability, longer placement times, patient discomfort and injury, can now, for many blocks, be dispensed with.
Several studies have shown increased efficacy and safety when using ultrasound to aid regional anesthesia when compared with the traditional landmark and nerve stimulation techniques. Furthermore, the use of ultrasound has shed some light on the failings of nerve stimulation. Nerve puncture and intraneural injection of LA does not always lead to nerve injury.
In the last year alone there has been a large number of excellent studies published that provide more evidence that ultrasound will soon become the main method of guidance in regional anesthesia.