Injection pressures measuring for a safe peripheral nerve block

The performance of a precise and safe peripheral nerve blockade (PNB) can currently rely on the aid of the ultrasounds and nerve stimulators. The injection pressure monitoring may be beneficial to perform a safer procedure. This review focuses on the pressures measured during PNB among studies conducted on animal, and human models. From a deep research among the PubMed/MEDLINE database for all reports published in English between January 2004 and November 2018, we selected 15 original papers. We excluded those that were reviews, case-reports, recommendations and correspondences, that did not match with object of our study. We highlighted the available systems for monitoring injection pressures and classified the reports on the basis of the model used for the respective study (animals, humans, in vitro). Intraneural injections were associated with lower pressures than perineural ones. High injection pressures registered at the needle tip were associated with an increased risk of nerve damage. To date, a precise cut-off pressure value has not yet emerged from the literature for a safe PNBs, but based on the recent literature, it can be stated that the threshold of 15 psi is an acceptable value under which a perineural injection can be performed during a PNB to achieve a safer procedure. So it is desirable to make further studies in order to assess them. In the future, the monitoring of the pressure could allow the use of a minimal quantity of anesthetic, empowering the safety of the nerve blocks. Moreover, the sensitive system should not be invasive and it should not hinder the job of the anesthetists.