How to Prolong the Duration of Sensory Block After Regional Anesthesia?

Introduction

A peripheral nerve block can be understood as the infiltration of any kind of local anesthetic around a nerve branch or the nerve itself. This is used for provoking anesthesia or analgesia. There are several limitations to the use of postoperative analgesics. This is because the analgesic effect of a peripheral nerve block can last only for a few hours, post which the patient may experience moderate to severe levels of pain at the surgical site, and this may additionally result in the immediate need for any alternative analgesic therapy. There are several adjuvants that have been used in order to prolong the analgesic effect and duration of peripheral nerve block. A few of the most successful sensory blocks include intravenous Dexamethasone.

What Are the Recent Adjuncts to Prolong the Duration of Sensory Block After Regional Anesthesia?

Extended-release formulations of regional anesthetics, such as liposomal Bupivacaine, have been developed in order to prolong the changes made post-regional anesthesia for up to 96 hours. The real effect of these adjuncts, unfortunately remains far behind the medical team’s expectations because the effectiveness is only slightly better than Bupivacaine hydrochloride. Adjuvants to regional analgesics have been studied considerably with heterogeneous outcomes. Adjuvants are the recommended means to prolong any kind of regional anesthesia where and when needed.

• Dexamethasone is a commonly used adjunct that ranges amongst the most effective ways to prolong any single-injection nerve blocks. Dexamethasone is one of the most effective adjuvants, next to Dexmedetomidine. Both have a few side effects as well as a favorable safety profile.

• Continuous nerve blockings and catheter techniques can additionally have the potential to prolong regional anesthetics that seems to be extremely effective.

• On the flip side, these adjuncts are less cost-effective regarding nerve-blocking procedures, postoperative care as well as handling logistical issues mainly in ambulatory surgery.

• Nevertheless, a preferable course of analgesia prevailing for the initial 24 hour postoperative period is still not exactly a reliable achievement. The duration of single-injection local anesthesia is only limited because of the inherent pharmacological property of regional anesthetics.

• The ideal course of a local anesthesia block lasting for the initial one day period after an operation can be stated, and then a residual analgesia effect will be desirable.

Does Dexamethasone Prolong the Duration of Sensory Block After Regional Anesthesia?

A nerve block precludes or facilitates pain by interrupting distress signals that travel along a nerve to the brain. It involves an injection of local anesthetic, a numbing agent all around a nerve either while the surgery or immediately after the surgery. Pain relief from the nerve block can last only upto a few hours post surgery. After this patients may experience a moderate to severe level of pain. Dexamethasone is a steroid that can relieve pain as well as the inflammatory response to tissue being damaged post surgery because of heat, redness, and swelling at the surgical site. In patients receiving nerve block, Dexamethasone may be additionally given along with the local anesthetic agents all around the nerve, referred to as perineural, or directly into a vein, called intravenous in order to prolong the pain relief from the peripheral nerve block.

• When added to local anesthetics, Dexamethasone has shown to lengthen the period of peripheral nerve blocks; nevertheless, there exist only a limited amount of studies employing a large number of patients.

• A few evidence suggests that when Dexamethasone is used as an adjuvant to peripheral nerve blocks in surgeries of the upper limb, it may prolong the sensory block duration as well as effectively downsize the postoperative pain assertiveness.

• There is not adequate evidence in order to determine the significance of Dexamethasone as an adjuvant to peripheral nerve block in the surgeries related to the lower limb.

• There is additionally no evidence of the elongation in the nerve block by Dexamethasone in children as well.

What Are the Advantages and Drawbacks of Sensory Block After Regional Anesthesia?

A peripheral nerve block is an advanced technique of administrations of local anesthetic solution, commonly called as regional anesthesia, which is infiltrated near a nerve or directly inside the nerve in order to provide an analgesic effect. Sensory nerve blocks for the management of pain during both intraoperative as well as postoperative situations are associated with several advantages to the patients as well as the healthcare team that include the following mentioned below.

• Improved analgesia (pain relief).

• Fewer opioid‐related adverse reactions.

• By reducing the need for general anesthesia, regional anesthesia can minimize associated risks, such as postoperative nausea and vomiting, aspiration pneumonia, and cardiovascular complications.

• An earlier ambulation.

• A short stay at the hospital as against post an intravenous opioid analgesia.

In addition to the above, sensory block post regional anesthesia do have a few drawbacks as those mentioned below.

• The analgesic effect of the sensory block post regional anesthesia lasts only for a few hours.

• The pain perception of the patient is moderate in intensity but may turn to be severe as well at a later stage.

• There is always a need for adjuvant anesthesia.

• Peripheral nerve catheters that help in providing a continuous infusion of local anesthetic agent have been partially successful in prolonging the effects of local anesthesia.

• The continuous catheters demand a greater time along with expert skill in order to insert.

• The catheter may dislodge while it is in use.

• The catheter may be challenging to remove.

Conclusion

It is crucial to treat postoperative pain accurately. Patients who experience a severe amount of pain in the initial postoperative stages are generally at risk for the development of chronic pain that can have the potential to affect their quality of life dramatically. To supplement postoperative pain management, patients are often treated with several therapeutics such as opioids, which are once again associated with numerous sorts of adverse events that include respiratory depression, nausea with vomiting, pruritis and, constipation.There are several ways to prolong the sensory block post regional anesthesia but none of them are definitive till date and the research for a more established outcome is still being studied thoroughly.