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An overview of neuraxial

NEURAXIAL ANESTHESIA is the administra- tion of medication into the subarachnoid or to produce anesthesia and analgesia. It can lead to the complete ab- sence of sensory and/or motor function at or below the site of . Depending on the dose and concentration of the anes- thetic used, neuraxial anesthesia doesn’t al- ways result in a complete absence of motor function. For example, the goal of neurax- ial anesthesia administered to a woman in labor is to provide analgesia as she pro- Understand the gresses through active labor but not re- move her ability to move her lower ex- basics so you can tremities. The three most commonly used neuraxial techniques are spinal, epidural, effectively manage and combined spinal-epidural (CSE). (See your patients. When is neuraxial anes thesia used?) A major benefit of neuraxial anesthesia By Huy Vo, MSN, CRNA, and is the reduced need for parenteral , Dominick Berkery, MSN, CRNA which have many side effects (including respiratory depression, delirium, and GI disturbances) that are associated with car-

diac, pulmonary, and kidney complica- CNE 1.5 contact tions. A recent meta-analysis and systemat- hours ic review by Meng and colleagues found that neuraxial anesthesia is associated with LEARNING O BJECTIVES a lower incidence of these complications 1. Differentiate types of neuraxial anesthesia. as well as decreased blood loss and risk of 2. Identify complications of neuraxial anesthesia. thromboembolism when compared to 3. Discuss the nursing care of patients receiving general anesthesia. In addition, periopera- neuraxial anesthesia. tive and obstetric management with The authors and planners of this CNE activity have disclosed neuraxial anesthesia has led to improved no relevant financial relationships with any commercial com- patient satisfaction scores because of en- panies pertaining to this activity. See the last page of the arti- cle to learn how to earn CNE credit. hanced pain control and shortened hospi-

Expiration: 4/1/23 talizations.

10 American Nurse Journal Volume 15, Number 4 MyAmericanNurse.com To ensure competent care of patients who vertebrae). A is threaded through the receive neuraxial anesthesia, you should have Tuohy into the epidural space, and an infusion a fundamental knowledge of spine anatomy of a with or without an to help you understand the important differ- is initiated. Epidurals can be used to produce ences between spinal and epidural anesthesia anesthesia but are more commonly used to administration. (See Do you know your spine provide intra- and postoperative analgesia. anatomy? online at myamericannurse.com/ CSE administration. CSE anesthesia is a ?p=65158) You also should know how to ef- two-step process. First, a Tuohy needle is fectively monitor patient response to anesthe- placed in the epidural space. The spinal nee- sia, respond to complaints of pain, and ad- dle is then placed through the Tuohy, and a dress complications. Adverse events must be of local anesthetic is administered into immediately communicated to the patient’s the subarachnoid space. After the spinal nee- surgical team to mitigate harm. dle is removed, the epidural catheter is thread- ed through the Tuohy needle and its position Neuraxial techniques is confirmed. Local anesthetic can be adminis- Neuraxial anesthesia can be administered via tered either as a bolus or an infusion. spinal, epidural, or CSE routes. (See Spinal vs. .) How it works Spinal administration. To administer Anesthesia (the complete absence of sensory spinal neuraxial anesthesia and/or analgesia, a and motor function) is achieved when high needle is inserted through the ligaments be- concentrations of local anesthetic are used, tween the vertebrae and a one-time injection such as 0.75% for spinal adminis- of medication (approximately 1 to 2 mL of lo- tration and 0.25% bupivacaine for epidural ad- cal anesthesia with or without an opioid) is ministration. Analgesia (absence of pain) is placed into the subarachnoid space (the area achieved when a lower concentration of local between the arachnoid and ). anesthetic is used, such as 0.125% bupivacaine Epidural administration. An epidural is for epidural administration. concen- administered using a Tuohy needle that trations of local anesthetics are rarely used for pierces the ligaments between the vertebrae. spinal administration. The needle is inserted into the epidural space Local anesthetics work by bathing the (the area between the and the roots of the , inhibiting sodium channel transmission to block pain signals to the . The most common- When is neuraxial ly used local anesthetics for neuraxial anesthe- anesthesia used? sia are , bupivacaine, and ropivacaine. Opioids such as , , and hy- Neuraxial anesthesia is used in a variety of dromorphone can be coadministered with local clinical situations, including surgical, obstetric, anesthetics to produce a synergistic effect that and procedural. inhibits pain transmission. Surgical Analgesia duration depends on the type of • Abdominal local anesthetic used and whether it’s admin- • Orthopedic istered via a single injection or as a continu- • Thoracic ous infusion through epidural or CSE tech- • Urologic nique. Single spinal injections generally last 60

Obstetric/gynecology to 150 minutes depending on the anesthetic • Cesarean delivery used; epidural administration achieves anes- • Labor epidural thesia and/or analgesia as long as the catheter • Tubal ligation remains in the epidural space and a continu- ous infusion of medication is running. (See Procedural • How long will it last?) Cervical, thoracic, and/or epidural injections • Managing neuraxial analgesia Chronic In addition to analgesic efficacy, side effects, and complications, nurses must

MyAmericanNurse.com April 2020 American Nurse Journal 11 About dermatomes Extending from the spinal cord are 31 roots, each of which provides sensory innervation to a (specific area of skin). For example, a patient who has knee arthroplasty and receives an epidural for pain per the anesthesia provider’s order. For postoperative pain management will have analgesia at or below sensory infusions already running, the provider may in- dermatome level L1 (first ). Other common procedures crease the infusion rate. Instruct patients with and corresponding dermatome levels include: patient-controlled epidural analgesia (PCEA) Dermatome level Procedure how to use the bolus option to control pain. All changes to the infusion should be guided T4-T6 ...... Cesarean delivery by a clearly written anesthesia provider order. T8-T10 ...... Urologic procedures The most common medications used for PCEA are bupivacaine 0.625%-0.25% and ropivacaine T10 ...... Hip arthroplasty 0.625%-0.25% (either drug also may be given T11-T12 ...... Knee arthroplasty with fentanyl, morphine, or ). Both are typically administered at a basal infu- sion rate of 4 to 10 mL/hr and a bolus dose of assess the catheter insertion site, manage 3 to 6 mL. The lockout interval is usually 10 to epidural infusions, and potentially remove an 15 minutes, with the maximum hourly dose 22 epidural catheter if a patient transitions to oral to 34 mL. pain medications. Be sure to follow organiza- If the patient continues to complain of in- tion protocols and order sets. adequate analgesia even after the infusion rate When caring for a patient who’s received is increased, recheck the infusion system and neuraxial anesthesia, you’ll closely monitor his tubing and ensure the catheter hasn’t migrated or her blood pressure (BP), heart rate (HR), (the distance of the catheter from the insertion pulse oximetry, respiratory rate, pain percep- site should be marked on insertion) or been tion, and level of consciousness. Use a der- dislodged. Follow provider orders for break- matome map to assess the level of sensory through pain, bolus dosing, and infusion block and determine current motor function to pump settings related to an inadequate or ab- establish a baseline level of analgesia. (See sent level of analgesia. Notify the anesthesia About dermatomes.) The American Society of provider if the patient doesn’t experience any Anesthesiologists recommends that nurses fol- improvement in pain. low a patient-specific protocol established ei- Hypotension and bradycardia. Neuraxial ther by the patient’s care team or the organi- anesthesia can cause variable BP decreases that zation’s policy. frequently are accompanied by a decreased If a catheter is present, assess the insertion HR. Keep in mind that hypotension can be de- site. Also assess the infusion system and tub- fined in absolute parameters (for example, sys- ing to identify any detached connections, tolic BP less than 90 mmHg or mean arterial malfunctioning infusion pumps, or medica- pressure less than 65 mmHg) and in relative tion errors. Ensure are clearly la- terms (for example, a decrease in systolic BP beled, and avoid using tubing with any type greater than 20% of the patient’s baseline). of injection ports to limit the risk of inadver- Decreased BP with evidence of hypoperfu- tently administering a medication intended sion, such as mental status changes, requires for I.V. injection into the site. You’ll also want prompt treatment. Place the patient in the to be vigilant for inadequate analgesia and supine position. If the patient has adequate car- complications. diac and renal function, the provider may order a fluid bolus. Patients who don’t respond to Complications these initial treatments will require vasopressor Prompt recognition and treatment of compli- or inotropic agents, such as ephedrine, cations related to neuraxial anesthesia are es- , or epinephrine. Treat bradycar- sential in preventing lethal outcomes. dia (HR less than 60 beats per minute) as or- Inadequate analgesia. If a patient who re- dered with glycopyrrolate or ephedrine if mild- ceived a spinal anesthetic begins to complain ly symptomatic, or atropine if severe. of worsening pain, parenteral or oral analgesia Respiratory depression. Neuraxial anes- may be required. If an epidural catheter is thesia can affect the diaphragm and accessory present, assess the catheter, the insertion site, muscles of respiration, resulting in an im- and the level of dermatomal block. If an infu- paired cough reflex that diminishes the pa- sion hasn’t been started, initiate it to treat the tient’s ability to clear secretions. This effect is

12 American Nurse Journal Volume 15, Number 4 MyAmericanNurse.com Spinal vs. epidural administration

As illustrated below, a spinal anesthetic is injected into the subarachnoid space and an epidural is injected into the epidural space. more noticeable in patients with preexisting pulmonary disease. Opioids (particularly morphine) adminis- tered into the subarachnoid or epidural space have a duration of action up to 24 hours. In that time frame, any additional parenteral or Spinal cord oral opioids can amplify side effects. Monitor for signs of respiratory depression such as Spine bradypnea (less than eight breaths per minute), desaturation (pulse oximetry less than Nerve 90% on room air), grunting, or airway obstruc- Epidural anaesthetic tion. If respiratory depression occurs, stop any analgesic infusion and administer oxygen via a face mask at a minimum of 6 L/minute. Elevate the head of the bed to 45 degrees or higher, notify the anesthesia provider, and consider administering per provider order. Spinal anaesthetic Nausea and vomiting. Nausea and vomit- ing secondary to neuraxial anesthesia may be attributed to hypotension, neuraxial opioids, or GI hyperperistalsis. Aggressively treating of a dural puncture from a Tuohy needle is hypotension frequently prevents nausea and only about 1.5%, a greater than 50% chance vomiting. For symptoms unrelated to hy- exists that patients will develop PDPH from potension, administer antiemetics as ordered that puncture. The constant, throbbing head- by the provider. Small doses of anticholiner- ache typically is located in the frontal or oc- gics, such as atropine or glycopyrrolate, also cipital regions. Hallmark symptoms include a may be ordered. that worsens with sitting or standing Urinary retention. Anesthetic block of but improves when supine, neck stiffness, vi- the lumbar and sacral nerve roots leads to sual changes, subjective hearing loss, nausea, temporary loss of bladder function and an in- and vertigo. hibited void reflex. If a urinary catheter isn’t Notify the anesthesia provider if you sus- present, assess the patient for bladder disten- pect PDPH. Encourage patient bedrest in the sion until he or she is able to void. The inci- supine position, oral hydration, and increased dence of urinary retention has been reported caffeine consumption. Administer oral anal- to be as low as 5% and as high as 70%; how- gesics such as acetaminophen, butalbital, or ever, urinary retention may be influenced by caffeine as ordered and antiemetics as need- factors beyond neuraxial anesthesia, including ed. For debilitating PDPH that doesn’t re- urology and whether I.V. opioids were spond to conservative treatment, the anesthe- used during surgery. sia pro vider may place an epidural blood Pruritis. Incidence of pruritis related to opi- patch (injection of a small amount of autolo- oid administration via spinal or epidural routes gous blood into a patient’s epidural or spinal ranges from 69% to 83%. Opioid antagonists space to stop a CSF leakage) after patient (such as naloxone) or mixed opioid agonist- consent. antagonists (such as nalbuphine) can effective- High regional block/total spinal anes- ly treat opioid-induced pruritis. Diphenhydra- thesia. A high block or total spinal anesthesia mine also may be effective. can occur when large doses of local anesthetic Postdural puncture headache (PDPH). are injected via a catheter that’s mistakenly PDPH is a positional headache caused by placed in the intrathecal space or migrates af- cerebral spinal fluid (CSF) leakage through a ter placement. High block symptoms have a dural puncture. A PDPH is most common after rapid onset (usually less than 60 seconds) and a “wet tap” in which the anesthesia provider include nausea, dyspnea, hypotension, brady- inadvertently punctures the dura with the cardia, and weakness and numbness in the Tuohy needle. A recent meta-analysis by Choi upper extremities. A total spinal presents with and colleagues showed that although the risk unconsciousness, apnea, and profound hy-

MyAmericanNurse.com April 2020 American Nurse Journal 13 How long will it last? Neuraxial anesthesia onset and duration of action depends on the administration route and anesthetic used. denly complain of these symptoms and alert Spinal anesthesia Onset (minutes) Duration of action the anesthesia team immediately. Hematomas (minutes) will be surgically evacuated. Bupivacaine 5-8 90-150 Neuraxial anesthesia and Ropivacaine 3-5 60-100 antithrombotic therapy Some surgical patients take antithrombotic 2-4 80-120 therapy (for example, , clopidogrel, and aspirin) to treat conditions such as venous Epidural anesthesia thromboembolism or atrial fibrillation or, in the case of those with cardiac stents and/or Bupivacaine 10-15 Continuous with infusion mechanical heart valves, as a preventive meas- ure. The decision to proceed with neuraxial Ropivacaine 10-15 Continuous with infusion anesthesia for surgery in patients receiving an- tithrombotic therapy is based on an assess- ment of the risks of bleeding and thrombosis potension. Notify the anesthesia team immedi- when therapy is discontinued. Failure to dis- ately and prepare for possible advanced car- continue antithrombotic medications before diac life support (ACLS) interventions. The in- neuraxial anesthesia administration predispose cidence of a high regional block or total spinal these patients to the risk of a spinal or epidural anesthesia is approximately 0.02%. hematoma. Systemic toxicity. Large volumes of local Instruct surgical patients to stop taking an- anesthesia can mistakenly be injected into a tithrombotic medications before the day of sur- blood vessel during epidural placement, caus- gery. (The time frame for stoppage depends on ing the anesthetic serum level to rise above a the medication.) After surgery, monitor patients toxic threshold and resulting in local anesthe- for signs of a spinal or and sia systemic toxicity (LAST). LAST, which is ensure they resume antithrombotic medications rare (less than 0.2%), affects the neurologic per provider orders. Some patients will require and cardiovascular systems and may be fatal if postoperative bridge therapy (for example, low treatment is delayed. Early symptoms include molecular weight heparin [such as enoxaparin] tinnitus and a metallic taste in the mouth. or unfractionated heparin). The American Soci- Signs of toxicity can rapidly progress to , ety of Regional Anesthesia and Pain Medicine loss of consciousness, hypotension, arrhythmia, has developed guidelines for when to remove and circulatory collapse. Notify the anesthesia neuraxial catheters and when to re-initiate an- team and prepare for possible ACLS interven- tithrombotic medications to reduce bleeding tions. Lipid therapy, administered by risk. The University of Washington has a an ex- the anesthesia provider, also is indicated for cellent reference that can be found online at LAST. Become familiar with where and how to bit.ly/3bwqBin. obtain lipid because timely admin- istration is essential to reduce the risk of car- Ensuring good outcomes diac arrest. Proper nursing care and management helps Epidural and spinal hematoma. Epidural ensure good outcomes for patients who re- and spinal hematomas are among the rarest ceive neuraxial anesthesia. Prompt identifica- neuraxial anesthesia complications (incidence tion and communication of complications and ranges from 1 in 150,000 to 1 in 220,000). Pa- adverse events coupled with swift interven- tients with a hematoma usually will complain tion can mitigate harm and ultimately prevent of sudden sharp back pain (from the insertion permanent injury. AN site) that radiates to the leg. Generalized weakness along with bladder and bowel dys- Visit myamericannurse.com/?p=65158 to view refer- function also may indicate a hematoma. Be- ences, a case study, and information on spine anatomy.

cause a definitive diagnosis can be achieved *Name is fictitious. only with magnetic resonance imaging and computed tomography, you should have a The authors are senior staff certified registered nurse anesthetists high degree of suspicion when patients sud- at the UCLA Medical Center in Los Angeles, California.

14 American Nurse Journal Volume 15, Number 4 MyAmericanNurse.com CNE An overview of neuraxial anesthesia POST-TEST • CNE: 1.5 contact hours Earn contact hour credit online at myamericannurse.com/article-type/continuing-education

Provider accreditation ANA Center for Continuing Education and Professional Devel- The American Nurses Association is accredited as a provider of opment’s accredited provider status refers only to CNE activities nursing continuing professional development by the American and does not imply that there is real or implied endorsement of Nurses Credentialing Center’s Commission on Accreditation. any product, service, or company referred to in this activity nor Provider Number 0023. of any company subsidizing costs related to the activity. The author and planners of this CNE activity have disclosed no rele- Contact hours: 1.5 vant financial relationships with any commercial companies ANA is approved by the California Board of Registered Nursing, pertaining to this CNE. See the banner at the top of this page Provider Number CEP17219. to learn how to earn CNE credit. Post-test passing score is 80%. Expiration: 4/1/23

Please mark the correct answer online. 4. The dermatome level for an anesthetic 8. Which statement about respiratory administered for a patient undergoing hip function and neuraxial anesthesia is cor- 1. To administer spinal anesthesia, a nee- arthroplasty is rect? dle is a. lumbar 2. a. Neuraxial anesthesia does not affect a. inserted between the dura mater and the diaphragm or accessory muscles. vertebrae. b. thoracic 4. b. If respiratory depression occurs, the pa- b. inserted into the center of the dura c. lumbar 10. tient should be placed flat in bed. mater. d. thoracic 10. c. Respiratory depression is unlikely to oc- c. placed into the subarachnoid space. 5. The middle meningeal layer of the cur more than 2 hours after drug ad- d. placed into the vertebral space. spinal cord is called ministration. 2. Which statement about how local a. subarachnoid. d. Neuraxial anesthesia can cause an im- anesthetics work is correct? b. arachnoid. paired cough reflex. c. pia mater. a. They bathe the nerve roots of the 9. Aggressive treatment of what condi- spinal cord, inhibiting sodium channel d. dura mater. tion frequently prevents nausea and vom- transmission to block pain signals to iting after neuraxial anesthesia? the central nervous system. 6. Which medication used for spinal anes- a. Hypotension b. They block the nerve roots of the thesia starts working in 2 to 4 minutes? b. Hypertension spinal cord, inhibiting calcium channel a. Chloroprocaine transmission to block pain signals to b. Bupivacaine c. Rapid respiratory rate the central nervous system. c. Ropivacaine d. Bradycardia c. They block the nerve roots of the spinal d. Lidocaine 10. A complication that is associated with cord, inhibiting chloride channel trans- an anesthesia provider inadvertently mission to block pain signals to the 7. A common basal infusion rate for pa- puncturing the dura with a Tuohy needle is central nervous system. tient-controlled epidural anesthesia a. systemic toxicity. d. They bathe the nerve roots of the (PCEA) with ropivacaine is spinal cord, inhibiting potassium chan- a. 1 to 3 mL/hr. b. urinary retention. nel transmission to block pain signals b. 3 to 5 mL/hr. c. postdural puncture headache. to the central nervous system. c. 4 to 10 mL/hr. d. bradycardia. 3. Depending on the anesthetic used, sin- d. 12 to 14 mL/hr. 11. Lipid emulsion therapy is indicated to gle spinal injections usually last for treat the complication of a. 25 to 30 minutes. a. high regional block. b. 30 to 45 minutes. b. systemic toxicity. c. 60 to 150 minutes. c. total spinal anesthesia block. d. 90 to 180 minutes. d. epidural hematoma.

MyAmericanNurse.com April 2020 American Nurse Journal 15