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The Four Blocks of the Chest: A Comprehensive Guide 


The world of regional anesthesia is ever-evolving, with new techniques and blocks being developed to provide effective pain management for various surgical procedures. Among these, four blocks have gained prominence for their efficacy in managing pain in the chest area: the Infraclavicular, PEC I, PEC II, and Parasternal blocks. Let's delve into each of these blocks to understand their applications and benefits. 

 

Infraclavicular Block 

The Infraclavicular block targets the brachial plexus at the level of the coracoid process. It's commonly used for surgeries of the lower arm, as it provides anesthesia to the arm and elbow. This block is advantageous due to its consistent landmarks and the ability to maintain distal upper limb tourniquet without discomfort. 

 

1.      Positioning: Place the patient supine with the arm abducted. 

2.      Landmarking: Identify the coracoid process and the infraclavicular fossa. 

3.      Ultrasound: Use a high-frequency linear transducer to visualize the axillary artery and the cords of the brachial plexus. 

4.      Needle Insertion: Insert the needle in-plane from lateral to medial, aiming to deposit local anesthetic in a U-shape around the axillary artery. 

 

PEC I Block 

The PEC I block, or Pectoralis I block, is a fascial plane block that anesthetizes the medial and lateral pectoral nerves, which innervate the pectoralis muscles. This block is performed by injecting local anesthetic in the fascial plane between the pectoralis major and minor muscles [1]. It's particularly useful for surgeries involving the pectoralis major muscle, such as breast surgery, pacemaker insertion, and portacath placement. 

 

1.      Positioning: The patient should be supine with the arm abducted. 

2.      Ultrasound: Place a high-frequency linear ultrasound probe below the clavicle to identify the pectoralis major and minor muscles. 

3.      Needle Insertion: Insert the needle in-plane, lateral to medial, to deposit local anesthetic between the pectoralis major and minor muscles. 

 

PEC II Block 

Building on the PEC I block, the PEC II block includes an additional injection lateral to the PEC I injection point in the plane between the pectoralis minor and serratus anterior muscles. This block aims to provide analgesia to the upper intercostal nerves, making it suitable for more extensive breast surgeries that involve the pectoralis major and minor muscles, the serratus anterior muscle, and the axilla. 

 

1.      Positioning: Similar to the PEC I block, the patient is supine with the arm abducted. 

2.      Ultrasound: After performing the PEC I block, move the probe distally and laterally towards the axilla to identify the plane between the pectoralis minor and serratus anterior muscles. 

3.      Needle Insertion: Insert the needle in-plane, lateral to medial, to deposit local anesthetic in the fascial plane between the pectoralis minor and serratus anterior muscles. 

 

Parasternal Block 

The Parasternal block is a newer technique that provides analgesia to the anterior chest wall. It's performed by injecting local anesthetic near the internal thoracic artery, lateral to the sternum. This block is beneficial for surgeries involving the sternum and ribs, including cardiac surgery and breast reconstructions. 

 

1.      Positioning: The patient is placed supine with the chest area exposed. 

2.      Ultrasound: Use a high-frequency linear probe to scan in a parasagittal fashion medial to the mid-clavicular line over the third and fourth ribs. 

3.      Needle Insertion: Insert the needle in-plane, aiming to deposit local anesthetic in the transversus thoracic plane between the internal intercostal muscle and the transversus thoracic muscle. 

 

Improving the Success 

Success rates of regional blocks is crucial for effective pain management and patient satisfaction. Here are some tips that can help enhance the success rates of regional anesthesia blocks: 

1.      Thorough Knowledge: Ensure a deep understanding of the anatomy involved in the block. Familiarity with the variations in nerve paths and potential obstacles is key [1]. 

2.      Ultrasound Guidance: Utilize ultrasound guidance to improve accuracy. Visualizing the needle path and the spread of local anesthetic can significantly increase success rates [4]. 

3.      Patient Positioning: Proper patient positioning is essential. It can facilitate needle placement and improve the distribution of the anesthetic agent [2]. 

4.      Aseptic Technique: Maintain strict aseptic techniques to prevent infections and complications. 

5.      Aspiration Tests: Perform gentle and frequent aspirations before injecting the local anesthetic to avoid intravascular injections [5]. 

6.      Use of Adjuvants: Consider using adjuvants to local anesthetics to prolong block duration and improve analgesia quality. 

7.      Incremental Dosing: Inject the local anesthetic incrementally to reduce the risk of systemic toxicity and to allow for the identification of incorrect needle placement. 

8.      Patient Communication: Engage in clear communication with the patient throughout the procedure. Their feedback can provide valuable information on the block's efficacy. 

9.      Practice and Training: Regular practice and continuous education can improve skills. Attend workshops and simulation training sessions to stay updated with the latest techniques [1]. 

10.   Peer Review and Feedback: Encourage peer review and constructive feedback on technique and outcomes to foster continuous improvement. 

11.   Documentation: Keep detailed records of each block performed, including patient responses and outcomes. This can help in refining techniques over time [3]. 

12.   Surgeon Collaboration: Work closely with surgeons to ensure that the timing and type of block are optimal for the surgical procedure [3]. 

 

By incorporating these strategies, anesthesiologists can enhance the efficacy of regional blocks, leading to better postoperative outcomes and higher patient satisfaction. Remember, the key to success is a combination of knowledge, skill, and the right tools. 

 

In Conclusion 

The Infraclavicular, PEC I, PEC II, and Parasternal blocks are essential components of modern regional anesthesia. They provide targeted pain relief, reduce the need for systemic analgesics, and contribute to faster patient recovery. As research continues, we can expect further refinements in these techniques, enhancing their effectiveness and expanding their applications. 

 

This blog provides a brief overview of the four chest blocks used in regional anesthesia. For detailed information on the indications, techniques, and outcomes of these blocks, please refer to the comprehensive resources available through professional medical organizations and peer-reviewed journals


 

 Valkyrie Simulators and Workshops offer hands on learning and practice for more than 30 ultrasound guided nerve blocks. 



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