Ultrasonography-guided nerve block

Ultrasonography-guided nerve block


Ultrasound-guided nerve blocks were first described in anesthesiology literature in 1978 when La Grange et al. utilized a Doppler device while performing supraclavicular brachial plexus blocks 1)


An Ultrasonography-guided nerve block is a procedure used for pain management by delivering anesthetic directly to nerves under ultrasound guidance. UGNBs are commonly used in emergency departments, operating rooms, and pain management settings as part of a multimodal approach to analgesia.

1. Ultrasound Guidance: UGNBs are performed using an ultrasound device, which helps visualize the targeted nerve and surrounding anatomy. This visualization enables precise placement of the anesthetic, reducing the risk of complications.

2. Anesthetic Injection: Once the nerve is located, a needle is inserted near the nerve, and the anesthetic is injected. The ultrasound ensures that the needle is in the correct position, minimizing the chances of injecting into blood vessels or other structures.

3. Types of Nerve Blocks: Common UGNB types include:

  1. Fascia Iliaca Block: Often used for hip fractures or femoral nerve pain.
  1. Interscalene Block: Commonly for shoulder surgeries.
  1. Axillary Block: For hand or forearm procedures.
  1. Popliteal Sciatic Block: For foot and ankle surgeries.

1. Pain Management in Acute Settings: UGNBs are widely used for immediate pain relief in trauma cases, orthopedic injuries, and post-surgical pain. In emergency departments, they provide rapid pain control, often avoiding or reducing the need for opioid medications.

2. Opioid-Sparing Effects: As UGNBs target specific nerves, they can achieve high levels of pain relief without the systemic side effects of opioids, reducing risks associated with opioid use, such as dependence and respiratory depression.

3. Improved Patient Comfort and Outcomes: By offering more effective pain control with fewer systemic side effects, UGNBs improve overall patient satisfaction and can facilitate earlier patient discharge and recovery.

1. Low Complication Rates: UGNBs, particularly with ultrasound guidance, have shown low rates of complications. Ultrasound visualization reduces the risk of nerve damage, vessel puncture, and incorrect injection sites, which are higher risks in blind (non-ultrasound-guided) blocks.

2. Training and Skill Requirements: The success and safety of UGNBs largely depend on the operator’s skill. Training in ultrasound use and nerve identification is essential, and studies suggest that, with adequate training, even less experienced clinicians can perform UGNBs effectively and safely.

3. Adverse Events: Although rare, complications like local anesthetic systemic toxicity (LAST), nerve injury, or infection can occur. Proper technique and knowledge of ultrasound-guided procedures significantly mitigate these risks.

Studies on UGNBs in emergency and acute care settings support their effectiveness and safety. They show that UGNBs can achieve significant pain relief, with many patients reporting reductions in pain scores by 50% or more. Moreover, complication rates remain low, with UGNBs increasingly recommended as part of multimodal pain management, especially for patients who may benefit from opioid-sparing strategies.

Conclusion

Ultrasonography-guided nerve blocks are a valuable tool in modern pain management. By allowing precise nerve targeting, UGNBs offer significant pain relief with minimal systemic effects, positioning them as a safe, effective alternative or supplement to opioid medications in various medical settings. As UGNBs gain wider adoption, consistent training, and quality control will be essential to maximize their benefits and ensure patient safety.

Design, setting, and participants: This cohort study included data from the National Ultrasound-Guided Nerve Block Registry, a retrospective multicenter observational registry encompassing procedures performed in 11 EDs in the US from January 1, 2022, to December 31, 2023, of adult patients who underwent a UGNB.

Exposure: UGNB encounters.

Main outcomes and measures: The primary outcome of this study was complication rates associated with ED-performed UGNBs recorded in the National Ultrasound-Guided Nerve Block Registry from January 1, 2022, to December 31, 2023. The secondary outcome was patient pain scores of ED-based UGNBs. Data for all adult patients who underwent an ED-based UGNB at each site were recorded, as were the volume of UGNB at each site and procedural outcomes (including complications). Data were analyzed using descriptive statistics of all variables.

Results: In total, 2735 UGNB encounters among adult patients (median age, 62 years [IQR, 41-77 years]; 51.6% male) across 11 EDs nationwide were analyzed. Fascia iliaca blocks were the most commonly performed UGNBs (975 of 2742 blocks [35.6%]). Complications occurred at a rate of 0.4% (10 of 2735 blocks). One episode of local anesthetic systemic toxicity requiring an intralipid was reported. Overall, 1320 of 1864 patients (70.8%) experienced 51% to 100% pain relief following UGNBs. Operator training levels varied, although resident physicians performed in 1953 of 2733 procedures (71.5%).

Conclusions and Relevance: The findings of this cohort study of 2735 UGNB encounters support the safety of UGNBs in ED settings and suggest an association with improvement in patient pain scores. Broader implementation of UGNBs in ED settings may have important implications as key elements of multimodal analgesia strategies to reduce opioid use and improve patient care 2)


This study, published in *JAMA Network Open*, investigates the complication rates and effectiveness of ultrasonography-guided nerve blocks (UGNBs) as a modality for acute pain management in emergency department (ED) settings. Based on 2735 UGNB procedures from 11 EDs in the U.S., the study found a complication rate of 0.4%, with significant pain relief observed in 70.8% of patients. This evidence underscores UGNBs’ safety and efficacy, making a strong case for their broader adoption in EDs.

Strengths of the Study:

1. Large Sample Size: With 2735 UGNB procedures, this study offers substantial statistical power, lending robustness to its findings regarding complication rates and pain management effectiveness.

2. Multicenter Data Collection: Data gathered from 11 different EDs across the U.S. adds diversity to the sample, increasing the generalizability and relevance of the findings for other ED settings.

3. Low Complication Rate: The reported complication rate of 0.4% supports the safety profile of UGNBs, a key concern in emergency settings. The low incidence of adverse events, despite varied operator training levels, supports the feasibility of UGNB implementation.

4. Quantifiable Pain Relief: With 70.8% of patients experiencing substantial pain relief, the study successfully demonstrates the efficacy of UGNBs as an alternative to opioid-based pain management, highlighting its potential for reducing opioid use in acute pain settings.

Limitations and Areas for Improvement:

1. Lack of Control Group: The absence of a control group (e.g., patients receiving standard pain management without UGNBs) makes it difficult to attribute observed pain relief outcomes solely to UGNBs without considering other factors that might have contributed.

2. Variability in Operator Training: Although the study notes that most procedures were performed by resident physicians, it does not provide a detailed analysis of how operator experience levels may have impacted complication rates or pain outcomes. Further stratifying data based on operator training could yield insights into the learning curve associated with UGNBs.

3. Limited Analysis of Complications: The study briefly mentions a single case of local anesthetic systemic toxicity but lacks in-depth discussion on the nature of the complications or potential preventive measures. This aspect could be better explored to enhance understanding of specific risks associated with UGNBs.

4. Single-Country Focus: Since all data are from U.S. EDs, the study’s findings may not be as generalizable to EDs in other healthcare systems, where different training standards or equipment availability may influence UGNB safety and efficacy.

Implications for Practice:

The study’s conclusions are promising for EDs seeking multimodal analgesia solutions. Implementing UGNBs more broadly in ED settings could mitigate opioid dependency risks and enhance patient outcomes in acute pain management. However, integrating UGNBs would necessitate comprehensive training programs to ensure operator competency, especially among resident physicians, who conducted the majority of the blocks in this study.

Conclusion:

This study provides valuable insights into the role of UGNBs in ED pain management, underscoring their safety and effectiveness. While UGNBs show potential for wider application in ED settings, further research with controlled methodologies and a focus on operator training levels would help solidify the findings. In summary, the study presents a compelling case for UGNBs as part of multimodal analgesia in emergency care but underscores the need for continued evaluation of best practices for their safe and effective implementation.


1)

la Grange P, Foster PA, Pretorius LK. Application of the Doppler ultrasound bloodflow detector in supraclavicular brachial plexus block. Br J Anaesth. 1978 Sep;50(9):965-7. doi: 10.1093/bja/50.9.965. PMID: 708565.
2)

Goldsmith A, Driver L, Duggan NM, Riscinti M, Martin D, Heffler M, Shokoohi H, Dreyfuss A, Sell J, Brown C, Fung C, Perice L, Bennett D, Truong N, Jafry SZ, Macias M, Brown J, Nagdev A. Complication Rates After Ultrasonography-Guided Nerve Blocks Performed in the Emergency Department. JAMA Netw Open. 2024 Nov 4;7(11):e2444742. doi: 10.1001/jamanetworkopen.2024.44742. PMID: 39535792.

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