Repeat and rescue nerve blocks are used in regional anesthesia to treat breakthrough pain in the perioperative setting. These techniques involve administering an additional nerve block in the same or a different anatomical location to re-establish effective pain control. Although rescue nerve blocks can reduce reliance on systemic opioids and enhance patient satisfaction, they require careful consideration due to potential complications, such as local anesthetic systemic toxicity (LAST), nerve injury, and masking serious postoperative issues, like compartment syndrome.
Repeat and rescue blocks are primarily indicated when the effects of the initial regional anesthetic wear off prematurely or fail to provide sufficient analgesia. Rescue blocks may also be necessary in cases of technical failure or catheter dislodgement in continuous block setups. Ramakrishnan et al. demonstrated the efficacy of bilateral external oblique intercostal plane blocks as a rescue technique for pain relief in patients with inadequate epidural analgesia following upper abdominal surgery. In their randomized trial, this approach provided superior pain management compared to intravenous morphine, highlighting the clinical value of rescue blocks within a multimodal pain management framework (1).
However, repeated dosing raises concerns about cumulative local anesthetic toxicity. Agents such as bupivacaine and ropivacaine have long half-lives, so re-administering them without careful monitoring can result in plasma concentrations that exceed safe limits. In their meta-analysis on transversalis fascia plane blocks for cesarean section analgesia, Kozanhan et al. emphasized the importance of adhering to recommended dose limits, particularly in obstetric patients, whose altered physiology may affect drug metabolism and distribution (2).
Patient selection plays a crucial role in determining whether a repeat block is appropriate. Factors such as age, body mass index, renal and hepatic function, and prior response to anesthetics must be considered. In orthopedic cases, where prolonged surgeries or challenging anatomy can limit the efficacy of nerve blocks, repeat blocks have been shown to offer meaningful benefits. For instance, Wang et al. studied arthroscopic shoulder surgeries and suggest that timely rescue blocks can reduce postoperative discomfort without increasing opioid use (3).
The technical aspects of administering a repeat block also require caution. Inflammatory changes, edema, or scarring after surgery can distort anatomical landmarks, complicating accurate needle placement and increasing the risk of intraneural or intravascular injection. Additionally, repeat blocks performed without image guidance may have a higher failure rate or risk of complications. Ahiskalioglu et al. emphasized the importance of ultrasound guidance when performing fascial plane blocks to enhance safety and efficacy, particularly in repeat or rescue scenarios (4).
Another critical consideration is the potential for masking evolving complications. Prolonged analgesia, for example, can obscure the clinical signs of compartment syndrome, delaying diagnosis and intervention. Therefore, the decision to perform a repeat block must be accompanied by vigilant clinical monitoring and clear documentation of neurological assessments before and after the block.
In summary, repeat and rescue blocks are valuable tools in regional anesthesia practice when used judiciously. They offer significant benefits in enhancing postoperative analgesia and reducing opioid use. However, their effectiveness hinges on appropriate patient selection, dose vigilance, anatomical precision, and continuous clinical assessment. As evidence grows, these techniques will likely continue to evolve, reinforcing their role in patient-centered pain management strategies.
References
- Srinivasaraghavan N, Seshadri RA, Ramasamy Y, et al. Bilateral External Oblique Intercostal Plane Block Versus Intravenous Morphine for Rescue Pain Relief in Patients With Epidurals Following Upper Abdominal Surgeries: A Randomized Controlled Trial. A A Pract. 2025;19(7):e02019. Published 2025 Jul 23. doi:10.1213/XAA.0000000000002019
- Tutar MS, Satici MH, Yildiz M, Kozanhan B. The analgesic effect of transversalis fascia plane block after cesarean section: a systematic review and meta-analysis of randomized controlled trials. Minerva Anestesiol. Published online July 28, 2025. doi:10.23736/S0375-9393.25.19105-0
- Zhang W, Guo Z, Hou X, Han C, Wang Z. Comparison of interscalene block with costoclavicular block for arthroscopic shoulder surgery: A meta-analysis. Medicine (Baltimore). 2025;104(29):e43094. doi:10.1097/MD.0000000000043094
- Dost B, DE Cassai A, Bugada D, et al. The analgesic effect of transversalis fascia plane block after cesarean delivery: a systematic review and meta-analysis with trial sequential analysis. Minerva Anestesiol. 2025;91(6):564-572. doi:10.23736/S0375-9393.25.18771-3