D I SASTE R FLIRTING WITH DO RNS GO TOO FAR WITH EPIDURALS?

Transcription

1 JACK STEM, RN, CRNA FLIRTING WITH D I SASTE R Labor pain managementbaa changed dramatically during the hst'20 years,. and recently the nurse's role with epidural anaf gesia and anesthesia has been called into question. Cost-cutting measures in hospitals and clinics have forced some RNs into roles typically, and advisedly, reserved for a certified anesthesia provider-sometimes to the mother and baby's peril. Epidural analgesia is a safe alternative for labor pain management if the patient has been properly prepared and is properly monitored. In fact, nurses play a vital role in prepping and managing women receiving epidural analgesia. Nurses flirt with disaster when they take on further epidural responsibilities for which they have not been properly trained or certified (AWHONN, 1996). Recent callers to the AWHONN Practice Line with questions about epidurals were asked to participate in an informal telephone survey about nurses rebolusing epidurals on the job. A majority of the callers indicated that they did so, yet they had little or no training in doing so. (To read the results of a FAX poll of AWHONN members about this practice, see "Nurses Speak Out, on page SO.) Understanding the physiology of epidural analgesia (pain relief) and anesthesia (sensory and/or motor black) is a starting point for nurses who want to become better managers of labor and delivery patients. The epidural space extends from the base of the skull to the tail bone's tip, and is widest in the lumbar region. The epidural space is filled with fatty tissue, blood \ chsels, and randomly placed septa, which the nurse anesthetist remains keenly aware of because these tissues can DO RNS GO TOO FAR WITH EPIDURALS? Because nurses take on the vital task of ensuring the safety of the mother and her newborn through labor and delivery, it's important that the nursing staff have a well-thought-out and consistent approach to monitoring labor and delivery patients. Beginning with the Basics Nurses working with epidural analgesia and anesthesia must have a thorough understanding of how they are administered and how they affect the patient and fetus. obstruct the flow of fluids injected into the epidural space. Poor catheter placement combined with inadequate volume can lead to pamal blocks or "hot" spots. The lumbar space is where spinal anesthetics are performed (subarachnoid block or intrathecal injection). Because the spinal cord terminates at L1-U, an "accidental" slip of a needle below this site is unlikely to cause any permanent damage, let alone paralysis. When lack Stem, RN, CRNA, is president of Midwest Anesthesia Consultants in Cincinnati, OH. February 1997 Lifollnor 31

2 THE FIRST CLUE OF WORRISOME HYPOTENSION IS A DECREASE IN THE FETAL HEART RATE, BECAUSE OXYGENATION VLA THE UTERINE ARTERY HAS ALREADY DECREASED. injecting the epidural space, five layers are traversed: skin, subcutaneous tissue, supraspinous ligament, interspinous ligament, and ligamentum flavum. Continuing deeper through the epidural space would take the needle tip through the dura mater, subdural space, arachnoid mater, subarachnoid space (also known as the theca), pia mater, and into the spinal cord. Nurses need to understand what occurs when local anesthetics are injected into the epidural space. Local anesthetic agents are the medications that affect the sympathetic, sensory, and motor nerve fibers exiting the spinal cord. These medications cause both the desired and undesired effects seen with epidural analgesia. The diameter of the nerve fiber and the concentration of local anesthetic both impact the medication s effectiveness. The sympathetic nerves are preganglionic, unmyelinated nerves with a small diameter; therefore, it takes less medication to essentially turn off the nerves. Nurses need to remember that any time local anesthetics are injected into the epidural space, a decrease in blood pressure must be anticipated. Adequate patient hydration before beginning the block is important to prevent precipitous drops in blood pressure. Additionally, because aspiration is the leading cause of maternal death from anesthesia, 30 ml of a clear antacid, such as sodium citrate (Bicitra, for example), should be given orally 30 minutes before the epidural is placed. Nurses should repeat this every 3 to 4 hours until the baby is delivered. To provide pain relief without sensory loss or motor block, the local anesthetic solution concentration is diluted. Most women receive adequate pain relief with to percent bupivacaine. Adding opiates (fentanyhfentanil) can enhance pain relief without increasing the risk of motor block or increased hypotension. Highly concentrated solutions, typically used for surgical procedures or various manipulations, provide profound sensation loss as well as muscle relaxation. These are necessary components of anesthesia, but a labor epidural that causes loss of motor function would be considered mismanaged. Opiates injected into the epidural space provide pain relief by diffusing through all three spinal cord layers to enter the laminae, where they bind with Mu and Kappa receptor sites. This alters the perception of pain without causing vasodilation or sensory or motor loss, and the patient can ambulate with this technique. Some women may require additional analgesia during second-stage labor, which is provided by adding local anesthetics in varying concentrations. Redosing an epidural by bolus injection, whether by syringe or pump, should be accomplished only by a licensed anesthesia provider, because this is the most likely time for life-threatening complications to occur. Although some nurses may be routinely asked to bolus an epidural, the American Association of Nurse Anesthetists (AANA) is quite specific in their position statements on pain relief by indwelling catheter techniques. Initial placement, dosing and all subsequent bolus dosing of labor epidurals is performed by a qualified anesthesia provider. (AANA) A test dose is important any time a catheter is reinjected. A small test dose of 3 to 5 ml of a local anesthetic solution should be injected by an anesthesia care provider after aspirating the catheter to assess for blood or cerebrospinal fluid return. A full 2 minutes is allowed to determine whether an intravascular or subarachndid injection has occurred. If the test dose is negative, then small amounts are injected (3-5 ml), allowing at least 2 minutes between each injection to prevent a possibly fatal reaction should the catheter actually be intravascular or subarachnoid. Before the Epidural Nurses play an important role in preparing the woman and fetus before the CRNA administers epidural analgesia, because the altered physiology of pregnancy places the patient at higher anesthetic risk. Laboratory work isn t always necessary before placing an epidural catheter. Suspicion of pre-eclampsia or pregnancy-induced hypertension may be an indication to order a platelet count and other clotting studies to determine possible presence of a coagulopathy-a contraindication for major regional analgesia. Damage to an epidural vein can lead to epidural hematoma formation, with compression and ischemia of the spinal cord. But if the patient has a negative history for bleeding (previa, abruption, etc.), and her last hemoglobin level was within normal limits, then additional testing is not required. The position a woman assumes affects aortocaval compression to a great extent, and spread of the epidural medication to a lesser extent. The side-lying position is most effective in relieving aortocaval compression and enhancing oxygenation. If side-lying is not possible, using a wedge in the supine position to displace the buttocks is acceptable. Lying flat is prohibited because it creates aortocaval compression, and has little effect in the spread of the epidural medication, because the injection volume determines spread more so than gravity. During slow infusions, gravity will have a much greater influence on the movement of the analgesic solution; therefore, the patient may be turned every 15 to 30 min- Utes to ensure an even spread. Nurses should closely watch the woman receiving epidural anesthesia for signs of hypotension and increasing motor block and the possibility of catheter migration into an epidural vein or subarachnoid space. After any bolus dose, the anesthesia provider should remain for at least 20 minutes to ensure no life-threatening complication has occurred. 32 Lifelines February 1997

3 Vasodilatation and hypotension are expected; therefore, blood pressure must be watched closely. Sympathetic block is most intense in the first 10 to 20 minutes. Ideally, nurses should monitor blood pressure every 2 minutes (5 times), and if stable, then every 5 minutes (twice). If the mother and fetus remain stable, blood pressure should be monitored every 15 minutes thereafter, unless the maternal or fetal condition dictates otherwise. Additional monitoring parameters include pulse oximetry and electrocardiogram when indicated, although oximetry and electrocardiogram monitoring are not a standard of care for analgesic epidurals. Pulse and respirations should be taken at least every 15 minutes, with blood pressure assessments. Progress of labor, fetal heart rate, level of block, and pain relief should also be assessed every 15 minutes. Should the level of pain block rise above dermatome T-10 (the general region around the belly button), to approximately T-6 (the area around the tip of the breastbone), anesthesia personnel should be notified to determine drug concentration or infusion rate changes. As the level of block increases, so do the risks for profound hypotension. As labor progresses, nurses should raise the head of the patient's bed to ensure adequate block through the perineum. Using a flow sheet to record assessments is strongly recommended. A well-designed flow sheet will give ongoing information about the woman's analgesia, response to medications administered, and response to interventions if adverse effects should occur. The nursing staff may discontinue the infusion any time the woman or fetus indicates intolerance to the procedure. However, the nursing staff should obtain an order from the anesthesia staff or obstetrician to discontinue the infusion if the woman is unable to push adequately. The unique physiology of pregnancy renders the woman more susceptible to the cardiovascular and central nervous system toxicity of local anesthetics, espe- cially bupivacaine. Any time a nurse suspects side effects of an epidural infusion in the woman or fetus, the pump should be turned off and the anesthesia staff should be contacted immediately. Nurses can never err by turning off the pump if complications are suspected. Complications and Strategies Significant complications, although rare, can have serious adverse effects on the woman and fetus. Major complications include hypotension, intravascular injection, high block, and dural puncture headache. Hypotension is the single-most detrimental side effect to the fetus. Maternal hypotension is determined by changes in the woman's baseline blood pressure, not a set systolic pressure. The mother's response to hypotension will be vasoconstricting major arterioles, including the uterine artery, further decreasing fetal perfusion. Simply stated, blood goes to the vital organs, and not to the baby. The mother may appear to be "fine" while fetal compromise continues. This can be deceptive because intrauterine hypotension occurs before the change is noted at the brachial artery. A maternal brachial artery blood pressure that appears "normal" does not adequately reflect intrauterine blood flow. The first clue of worrisome hypotension is a decrease in the fetal heart rate, because oxygenation via the uterine artery has already decreased. In addition, aortocaval compression can significantly enhance this hypotensive effect by decreasing preload (cardiac filling); therefore, the pregnant woman should never lie flat on her back. Any time the mother appears stable but the fetus' condition is deteriorating, intrauterine hypotension should be considered. The best definition of hypotension is a 20 percent drop in systolic blood pressure from baseline. Nurses shouldn't wait for maternal or fetal symptoms to occur to treat this problem. The fetus does not tolerate interruptions in blood flow. The sympathetic nerves are the EPIDURAL AGENTS local anesthetics used for labor pain relief: The most common dosage, % to 0.25% bupivacaine, is used in conjunction with 2 to 5 mg/ml fentanyl 0.5% to 1.5% lidocaine 1 % to 3% 2-chloroprocaine Opiates used as analgesics in the epidural space: Fentanyl 50 to 100 mg loading dose Infusion is 2 to 5 mglml Infused at 5 to 15 ml/hour Morphine An epidural is given mostly for postoperative pain relief Lasts approximately 16 to 24 hours Dosage range, 5 to 1.5 mg After dosing Signs and symptoms of intravascular injection: Numbness of lips, tongue, and teeth "Ringing in ears" Drowsiness Apprehension (with epinephrine solutions) Tachycardia (with epinephrine solutions) Follow with appropriate actions: Stop infusion or injection Deliver oxygen via mask at 10 Uminute Notify anesthesia personnel stat Prepare to treat seizures or cardiac arrest Signs and symptoms of subarachnoid injection: Inability to move legs or feet Sudden and complete pain relief High block with large dose "Total" spinal with large doses Follow with appropriate actions: Begin oxygen if spontaneous respirations are present Assist ventilation with bag and mask as needed Follow hypotension protocol as needed Notify anesthesia personnel stat February 7997 Lifelines 1w

4 Typical Nursing Assessments During Epidural AnalgesidAnesthesia Observe for signs and symptoms of intravascular or subarachnoid injection Blood pressure every 2 minutes (5 times) Blood pressure every 5 minutes (twice) Blood pressure every 15 minutes thereafter Electrocardiogram and pulse oximetry are not required but may be used if patient s condition warrants Level of block (dermatone level) Adequacy of analgesia Fetal well-being first fibers affected; therefore, hypotension can be seen before analgesia or anesthesia is accomplished. Hypotension can be minimized by two relatively simple measures-adequate hydration and positioning. Most healthy women require 1 to 2 L of a balanced salt solution, such as lactated Ringer s solution, before epidural insertion and dosing. Bolusing with a large volume of glucose-containing solutions can lead to neonatal hypoglycemia. Many obstetricians and anesthesia personnel recommend a steady, basal infusion of D5LR ( myhour) to maintain adequate glucose levels for uterine muscle activity. Regardless of the cause of hypotension, the initial nursing management steps include (1) increasing infusion of intravenous fluids (open wide); (2) changing the mother s position (lower the head of the bed, elevate her legs, and do uterine displacement); and (3) delivering oxygen by mask (at least 5 Vminute). Should maternal and/or fetal deterioration continue, 5 to 10 mg ephedrine given intravenously every minute until maternal blood pressure is within 10 to 15 percent of baseline is indicated. Patients with hypertension react differently to vasoactive medications than those with normal blood pressure. This could result in significant hypertension and further complication, including abruption or cerebral hemorrhage. Ephedrine is manufactured and delivered in 1-ml ampules, with 50 mg/ml. This should be diluted with an appropriate diluent until a final concentration of 10 mg/ml is achieved (1 ml ephedrine with 4 ml of diluent). This is an appropriate nursing action and should be instituted in any facility where epidural analgesia is used. lntravascular Injection of local Anesthetics An intravascular injection of a local anesthetic can be fatal if it s not recognized early and managed immediately. Any time an epidural catheter is in place, tip placement must be verified before injecting large amounts of local anesthetics. Each subsequent dose is treated as a test dose. Large quantities of local anesthetics intravenously can lead to tinnitus, circumoral numbness, metallic taste, slurred speech, visual disturbances, muscle twitching and grand ma1 seizures. With bupivacaine, large doses can also lead to cardiac dysrhythmias, as well as cardiac arrest beyond resuscitative efforts. If epinephrine is in the mixture, apprehension and tachycardia may also be observed. Again, prevention is the key to ensuring the patient s safety in the face of this potentially fatal complication. Even when the first injection is without incidence, subsequent injections must be assessed in the same manner, because epidural catheters can migrate at any time during the labor process. Because of this, the peripartum nursing staff should not administer any bolus injections. Management of intravascular injection includes (1) stopping the infusion or injection; (2) administering oxygen by mask at 10 Uminute; (3) notifying anesthesia personnel stat; and (4) preparing to treat seizures and/or cardiac arrest. High Block The epidural catheter can migrate and perforate the dura and subarachnoid layers; therefore, the analgesidanesthetic is now a subarachnoid infusion or injection. Should this occur, the signs of spinal anesthesia will become evident. With small injections (test dose or slow infusion), muscle weakness, paralysis, rising level of block, lack of sensation, weakness of the hands, and difficulty in breathing or speaking may become evident. This can be life-threatening should the level of the block rise above T2. For this reason, all labor and delivery nurses should be proficient in establishing and maintaining the airway, including controlled ventilation with a bag and mask. Aspiration pneumonitis is a potentially fatal complication that may occur with hypotension, loss of consciousness, loss of airway reflexes and seizure activity that may occur with high blocks or intravascular injections. Nurses can minimize the risk of death from aspiration by administering clear antacids before the epidural and throughout the labor and delivery process. Hormonal changes during pregnancy causes the gastrointestinal tract to become less efficient. The esophageal sphincter may become ineffective, leading to reflux esophagitis (heartburn). The stomach becomes a double-pouched organ that obstructs gastric emptying. The pyloris is occluded, preventing passive emptying of liquids. Active peristalsis must be present for stomach contents to leave the stomach; therefore, gastric emptying is delayed as much as 6 hours. Dural Puncture Headache When an epidural is attempted, dural puncture is possible. Should dural puncture occur with a 17- or 18-gauge needle, a dural puncture headache may result from the excessive loss of cerebrospinal fluid when the patient is again erect. When upright, the brain will sink in the cranial vault, exerting traction on blood vessels and other intracranial structures, leading to headache. The only way to cure the headache is to stop cerebrospinal fluid leak through the dural puncture wound. To reduce the headache, keep the patient flat as much as possible, increasing fluid intake to stimulate cerebrospinal fluid production, and using mild analgesics as needed. Caffeine (orally or intravenously) may improve the headache, and other treatments also include abdominal binders and increased salt intake. 34 Lifelines Februery 1997

5 The dural puncture should heal within 5 to 7 days; however, the headache may be severe enough to warrant the definitive treatment: an epidural blood patch. In an epidural blood patch, approximately 10 to 20 ml of the patient's blood obtained under sterile conditions is injected into the epidural space and the resulting clot "patches" the dural puncture, stopping the cerebrospinal fluid leak approximately 1 hour after the patch. By properly preparing patients for epidural analgesia and anesthesia, and by assessing the patient's condition throughout the process, taking appropriate actions when needed, nurses contribute significantly to helping reduce the pain involved with labor and delivery. Registered nurses needn't flirt with disaster by increasing epidural dosing or by rebolusing epidurals. By working together, RNs and CRNAs can be an effective team if each nurse involved in the process understands hidher unique responsibilities and acts accordingly. + References Ackerman, W. E. (1992). Obstetric anesthesia pearls. San Mateo, CA: Appleton & Lange. American Association of Nurse Anesthetists. (1994). Professional practice manual for the certified registered nurse anesthetist. Park Ridge, IL: Author. Association of Women's Health, Obstetric and Neonatal Nurses. (1996). Obstetric epidural analgesia and the role of the professional registered nurse (clinical commentary). Washington, DC: Author. Association of Women's Health, Obstetric and Neonatal Nurses. (1996a). Role of the registered nurse (RN) in the management of the patient receiving analgesia by catheter techniques (epidural, intrathecal, intrapleural or peripheral newe catheters) (position statement). Washington, DC: Author. Glosten, B. (1994). Local anesthetic techniques. In D. Chestnut (Ed.), Obstetric anesthesia: Principles and practice (pp ). St. Louis: Mosby. Guyton, A. C. (1992). Human physiology and mechanisms of disease (5th ed.). Philadelphia: WB Saunders Co. Ostheimer, G. W. (1993). Manual of obstetric anesthesia (2nd ed.). New York: Churchill Livingstone. Snider, S. M. (1993). Anesthesia for obstetrics (3rd ed.). Los Angeles: Williams & Wilkins. Want more information on epidurals? Call the AWHONN FAX-on-Demand line at and request document R121: "The role of the Registered Nurse (RN) in the Management of the Patient Receiving Analgesia by Catheter Techniques" (epidural, intrapleural, or peripheral nerve catheters]. Check out the University of Pennsylvania's web site: penn.edu/histoty/epidural.html Plan to attend the session "Coping with Labor Pain: Multimodal Strategies," on June 15th at the 1997 AWHONN annual convention, "Capitol Opportunities," in Washington, OC. Call and request FAX document R303 for convention information. February 1997 Lifelines 31