PROCEDURE Peripheral Nerve Blocks : 107 Assisting with Insertion and Pain Management Kimberly Williams PURPOSE: Peripheral nerve blocks are administered as single local anesthetic injections or continuously through a catheter placed into a precise anatomical area to provide site-specifi c analgesia or anesthesia. PREREQUISITE NURSING • The anatomical position of the specifi c catheter should be KNOWLEDGE clearly defi ned and documented after insertion by the phy- sician or advanced practice nurse (e.g., femoral, axillary • State boards of nursing may have detailed guidelines [ Figs. 107-1 and 107-2 ], brachial plexus [ Fig. 107-3 ], involving peripheral nerve blockade. Each institution that intrapleural, extrapleural, paravertebral, tibial, sciatic, provides this therapy also has policies and guidelines per- lumbar plexus). 5,32 Radiological confi rmation 6 of the cath- taining to peripheral nerve blockade. It is important that eter position may be necessary to avoid suboptimal out- the nurse is aware of state guidelines and institutional comes (e.g., pneumothorax). Catheters may be placed by policies. 15 the surgeon, anesthesiologist, or certifi ed nurse anesthetist • The nurse must have an understanding of the principles under direct vision, via ultrasound scan–guided tech- of aseptic technique. 9,12,19,23,39 niques or with the use of a peripheral nerve stimulator, • The nurse assisting with the insertion of peripheral nerve either adjacent to or directly into the nerve sheath (e.g., blocks requires specifi c skills and knowledge. 15 sciatic or tibial nerve during surgery for lower-limb ampu- • Catheter placement and management of the patient should tation). 16,19,21,23,29,31 Catheters may also be placed after be under the direct supervision of an anesthesiologist, surgery (e.g., intercostal, intrapleural, axillary, brachial nurse anesthetist, or the acute pain service. 24,26,39 Periph- plexus, femoral, paravertebral; Table 107-1 ). eral nerve blocks are used as part of a preemptive and • A three-in-one peripheral nerve block can be used for multimodal analgesic technique to provide safe and effec- analgesia after proximal lower-limb orthopedic surgery. tive postoperative pain management with minimal side A three-in-one peripheral nerve block provides analgesia effects. 10,12,14,18,21 to block three nerves, including the lateral femoral cuta- • Peripheral nerve blocks are site specifi c (e.g., femoral, neous, femoral, and obturator nerves. 4,26 This block is as brachial plexus, axillary, intrapleural, extrapleural, para- effective as epidural analgesia, with fewer side effects vertebral, tibial, sciatic, lumbar plexus) and provide pro- than epidural analgesia (e.g., urinary retention, nausea, longed anesthesia or analgesia for postoperative and risk for epidural hemorrhage in patients with anticoagula- trauma pain management. 4,26 tion). 6,7,16,26,27 Some forms of plexus analgesia (e.g., bra- • Peripheral nerve blocks in the outpatient setting have chial plexus analgesia) in the postoperative setting may facilitated early patient ambulation and discharge by serve two purposes: pain relief and sympathetic blockade, decreasing side effects, such as drowsiness, nausea, and the latter of which increases blood fl ow and may improve vomiting. 3,11,13,18 In addition, unlike general anesthesia, outcomes in some cases (i.e., digit reimplantation).5,16,23,34 peripheral nerve blocks do not directly alter the level of • Analgesia via a catheter may be administered as a continu- consciousness. By preserving the patient ’ s level of con- ous infusion with the use of a volumetric pump system, sciousness, the patient ’ s protective airway refl exes (e.g., a patient-controlled regional infusion system, or a dis- cough and gag) are maintained and the need for airway posable pump device (e.g., elastomeric). An elastomeric manipulation and intubation is negated. Furthermore, with pump is one type of disposable infusion pump designed to the use of peripheral nerve blockade, the complications provide a constant rate of infusion from a fi lled reservoir. of general anesthesia are avoided. 3 Continuous periph- The infusion rates may or may not be adjustable ( Fig. eral nerve blockade improves postoperative analgesia, 107-4 ). 21,30,34 Medication administered is usually a local patient satisfaction, and rehabilitation compared with anesthetic (e.g., bupivacaine, ropivacaine). Other agents intravenous (IV) opioids for upper- and lower-extremity have been used on an adjunctive basis as a bolus, includ- procedures. 11,13,18,26,31 ing opioids, clonidine, epinephrine, 16,17 and neostigmine. 18 948 107 Peripheral Nerve Blocks: Assisting with Insertion and Pain Management 949 Axillary artery Median nerve Biceps muscle Coracobrachialis muscle Musculocutaneous nerve Median nerve Axillary fascia Ulnar nerve Radial nerve Ulnar nerve Figure 107-1 Location for needle insertion for an axillary block. (From Sinatra RS: Acute pain: Mechanisms & management , St Louis, 1992, Mosby.) Midclavicular point Infraclavicular injection site Axillary artery Figure 107-2 Needle insertion for an axillary block. (From Sinatra RS: Acute pain: Mechanisms & management , St Louis, 1992, Mosby.) • The pharmacokinetics and pharmacodynamics of local concentration of the medication, site of injection, and anesthetics and other agents used, including side effects absorption. The addition of a vasoconstrictor, such as epi- and duration of action, should be clearly understood. nephrine, constricts blood vessels and reduces vascular Local anesthetic medications used for peripheral nerve uptake, which further prolongs the duration of action of blocks provide surgical analgesia (i.e., loss of pain sensa- the local anesthetic. 16,17 Epinephrine is not recommended tion) and anesthesia (i.e., loss of all sensation). The dura- with peripheral nerve blocks in areas with end arteries, tion of action for each anesthetic medication depends such as ear lobes, the nose, digits, and the penis. 39 Vaso- on several factors, including the volume injected, constrictor medications may cause spasm of blood vessels, 950 Unit III Neurologic System External jugular vein Middle scalene muscle Trunks of the Cricoid brachial plexus cartilage Subclavian artery Anterior scalene muscle Figure 107-3 Landmarks for interscalene brachial plexus block. (From Sinatra RS: Acute pain: Mechanisms & management , St Louis, 1992, Mosby.) TABLE 107-1 Single-Shot (One-Time, Single Injection) and Continuous Peripheral Nerve Blocks Block Indications Practical Problems Interscalene Shoulder/arm pain (e.g., shoulder dislocation/fractures, humeral • Horner ’ s syndrome may obscure neurological fracture) assessment • Block of ipsilateral phrenic nerve • Close proximity to tracheostomy and jugular vein line sites Cervical Shoulder/elbow/wrist pain (e.g., shoulder fractures, humeral • Horner ’ s syndrome may obscure neurological paravertebral fracture, elbow fractures, wrist fractures) assessment (continuous • Block of ipsilateral phrenic nerve catheter only) • Patient positioning Infraclavicular Arm/hand pain (e.g., elbow fractures, wrist fractures) • Pneumothorax risk • Steep angle for catheter placement • Interference with subclavian lines Axillary Arm/hand pain (e.g., elbow fractures, wrist fractures) • Arm positioning • Catheter maintenance Intercostal Blockade used for management of pain due to traumatic rib • Catheter malposition fractures. Commonly an elastomeric infusion pump, which is a • Risk of pneumothorax balloon fi lled with local anesthetic attached to a catheter placed at the site of injury. This delivery system results in slow infusion of local anesthetic for pain control. This provides pain relief so that patients are able to ventilate more effectively. Paravertebral Unilateral chest or abdominal pain restricted to a few • Patient positioning dermatomes (e.g., rib fractures) • Stimulation success sometimes hard to visualize Combination of Unilateral leg pain (e.g., femoral neck fracture [femoral], tibial • Patient positioning femoral and and ankle fractures [sciatic]) * • Interference of femoral nerve catheters with sciatic block femoral lines * Caution: Compartment syndrome. Modifi ed from Schulz-Stubner S: The critically ill patient and regional anesthesia, Curr Opin Anaesthesiol 19:538–544, 2006. 107 Peripheral Nerve Blocks: Assisting with Insertion and Pain Management 951 • Pump for administration of analgesia (e.g., volumetric pump, dedicated for peripheral nerve block infusion with rate and volume limited, and preferably a different color from the epidural and IV infusion pumps; patient-controlled analgesic pump or a portable infusion device such as a disposable elastomeric continuous infusion pump • Specifi c observation chart for patient monitoring of the peripheral nerve block infusion • Prescribed analgesics and local anesthetics • Equipment for monitoring blood pressure, heart rate, and pulse oximetry Additional equipment, to have available as needed, includes the following: • Ice or alcohol swabs for demonstrating sensory block Figure 107-4 An elastomeric infusion pump. Parts include 1, • Emergency medications (e.g., 20% fat emulsion/intralipids fi lling port; 2, elastomeric balloon (drug-containing reservoir); and for local anesthetic toxicity) 3, outer protective shell. (Originally published in Skryabina E, • Bag-valve-mask device and oxygen Dunn TS: Disposable infusion pumps, Am J Health Syst Pharm • Equipment for end-tidal carbon dioxide monitoring 63:1260-1268, 2006.) © 2006, American Society of Health-System