Current devices used for the monitoring of injection pressure during peripheral nerve blocks

Introduction: Peripheral nerve blocks are generally safe. However, there is a small but real associated risk of needle-related complications such as nerve injury. Nerve injury has been associated with high pressure injections in animals, and some data supports the use of monitors to limit injection pressure during these procedures.Areas covered: A literature search for articles with keywords 'injection,' 'pressure,' and 'nerve' was conducted. All currently available devices designed to monitor injection pressure and/or prevent high pressure injections were reviewed. There are three classes of devices that are used to monitor injection pressure. The first is based on Boyle's Law, and involves the clinician limiting the compression of a known quantity of air in the syringe, thereby preventing a corresponding increase in pressure. The second is the use of electronic pressure manometers present in syringe pumps. Finally, two specialized in-line devices, the BSmart™ and the NerveGuard™, serve to warn of, or prevent, respectively, injection at high pressures.Expert commentary: While each of the reviewed methods has its advantages and drawbacks, all of the means of injection pressure monitoring are relatively simple and inexpensive to perform. More outcomes data are required to demonstrate a reduction in injury with their use.