A complete checklist assessment should be performed before preparing the patients. Such checklists have shown to reduce medical errors, and may include patients name and date of birth, planned surgical procedure, completion of consents, patient allergies, coagulation status, and the surgical site marked by the surgeon. Before placing a block, the patient should be monitored with pulse oximetry, electrocardiography, and blood pressure monitoring, as described in the American Society of Anesthesiologists' standards for basic anesthetic monitoring.

An IV access should be secured to administer rescue medication in an emergency or sedation if needed, and supplemental oxygen therapy should be started.As an anesthetic procedure, the standard and emergency anesthesia equipment and medications should be prepared, including airway equipment. Aseptic skin preparation is needed as a strict aseptic technique must be used for all the blocks, including sterile gloves, masks, and surgical drapes.

Neuraxial Anesthesia (Spinal/Epidural/Combined)

Neuraxial blocks consist of placing a needle through the back to inject a specific drug into the subarachnoid space for spinal anesthesia or in epidural space for epidural anesthesia. Both techniques can be applied together.[4]

Epidural Anesthesia

Epidural anesthesia is administered by introducing a needle between the lumbar, thoracic, or cervical vertebrae and injecting the anesthetic agents into the epidural space, directly or through a catheter. The sitting and lateral decubitus positions are commonly used. The epidural needle can be inserted using a midline or a paramedian approach; the latter is used more frequently for thoracic insertions. Once a spinal level is chosen, the epidural needle is placed in the interspace between two spinous processes and advanced through skin, soft tissue, and spinal ligaments until the needle's tip enters the epidural space, the loss of resistance can be recognized. The anesthetic solution may be injected directly through the epidural needle into the epidural space, but more commonly, a catheter is inserted into space, and an anesthetic solution is administered. A transparent, occlusive, sterile dressing should be placed over the catheter insertion site, and the catheter should be marked and secured to the patient body.

Spinal Anesthesia

To perform a spinal block, a local anesthetic is injected into cerebrospinal fluid in the lumbar spine to numb nerves that exit the spinal cord. This is achieved by placing a needle between the lumbar vertebrae and through the dura to inject the medication. As the spinal cord usually ends between the first and second lumbar vertebral bodies, spinal anesthesia should be performed no higher than that level to avoid damage to the cord. Spinal anesthesia is administered as a single injection, whereas when performing an epidural block, a catheter is usually placed to use a continuous infusion or subsequent boluses.

The most frequent use is for surgeries involving the lower abdominal, pelvis, and lower extremities. 

Peripheral Nerve Blocks

Peripheral nerve blocks are particularly used for surgical procedures involving the upper or lower extremities and nonsurgical analgesia. Ultrasound guidance and nerve stimulator techniques are typically used to locate the anatomic structures and define the placement of the needle or catheter. Different techniques are described depending on the specific body area that needs to be numbed and if the local anesthetic is placed near a nerve or group of nerves, or spread between muscle planes. The commonly used blocks are:[5][6]

• Upper extremity blocks (interscalene, suprascapular, infraclavicular, axillary, intercostobrachial, wrist, and digital nerve blocks.)
• Lower extremity blocks (lumbar plexus (psoas compartment), femoral nerve block, fascia iliaca, obturator nerve, popliteal, saphenous, ankle, and digital nerve block.)
• Scalp block
• Cervical plexus block
• Thoracic nerve blocks (intercostal, paravertebral, interfascial plane blocks)
• Abdominal nerve blocks (transversus abdominis plane, subcostal, rectus, ilioinguinal and iliohypogastric, transversalis fascia plane, and quadratus lumborum block)
• Pudendal and paracervical blocks

Please refer to the specific chapter for further information on peripheral nerve blocks.

Intravenous Regional Anesthesia 

Intravenous regional anesthesia or Bier block is a technique used for short procedures on the hand and forearm. It consists of replacing venous blood of the arm with local anesthetics. To perform a Bier block, an intravenous catheter is placed in the operative hand. Afterward, the arm is exsanguinated by lifting and allowing passive exsanguination, and then wrapping with an Esmarch bandage. A double pneumatic tourniquet is then placed and insufflated (first the distal, followed by the proximal one) 100 mmHg above the patient's systolic blood pressure. After checking the correct placement of the tourniquets, the Esmarch bandage can be removed once the distal cuff is released.

Typically a short-acting local anesthetic is given through the IV (usually 0.5% lidocaine or prilocaine if available), over 3 minutes, and waiting at least 30 minutes before the tourniquet is deflated to avoid the potential complication of local anesthetic toxicity. Intravenous regional anesthesia is not usually performed for lower limb surgery because larger amounts of local anesthetics would be required. Complications of this technique involve major local anesthetic toxicity (usually after deflation or tourniquet malfunction, where high systemic concentration may occur), dizziness, facial numbness, blurred vision, tinnitus, nerve damage, thrombophlebitis, and compartment syndrome. The benefit of the Bier block is that no special equipment is required, but in turn, no residual analgesia is provided; therefore, postoperative pain would need to be treated by systemic drugs or a surgical block.[7]

The safe practice of neuraxial anesthesia requires a profound knowledge of potential complications, incidence, and risk factors. Each technique is associated with specific complications. The main complications seen in regional anesthesia are block failure, neural injury, and local anesthetic toxicity. Permanent neurological injury in central neural blockades is rare, but transient injuries may occur more frequently (0.01 to 0.8%). Local anesthetics toxicity is rare (0.01%) and is more frequently associated with a regional nerve block. Although not frequent, allergic reactions to local anesthetics may occur.[8][9]

Postdural puncture headache is a common (<1%) complication related to epidural and spinal anesthesia. Backache is a frequent complaint of neuraxial anesthesia. The pain is usually mild and self-limiting, but it may last for several weeks.[10]

Central neural blockade may cause hypotension and severe bradycardia, most frequently seen with higher vertebral lever punctures. Epidural or spinal hematoma is rare but can cause irreversible damage if it is not diagnosed promptly. Epidural abscess is a serious but not frequent (0.07%) complication after neuraxial block.

Regional anesthesia has become one of the mainstays of perioperative pain management. It has significantly diminished postoperative pain in orthopedic and thoracic surgeries, reduced the use of general anesthesia in obstetrics, and provides significant reduction of perioperative pain, ultimately leading to improved patient outcomes.

There are risks and benefits to both neuraxial and general anesthesia. There are no clear advantages to one type of anesthesia over the other when either would be appropriate. Decisions about an anesthetic technique should be made based on different factors, including the patient, surgeon, type of procedure, and the anesthesiologists' preference. Specific protocols should be used to conduct regional anesthetic procedures to ensure patient safety and improve patient outcomes.

Nurses should be trained in preparing the equipment and drugs required. Also, specific monitoring should be placed before a block is performed. Besides monitoring and registering the vital signs, the effects of the regional anesthesia should be evaluated, and the level of pain measured.