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Anesthesia in the Perioperative Setting

The number of inpatient surgical procedures performed annually stands at 51.4 million, according to the Centers for Disease Control and Prevention.1 About 60,000 people undergo surgery daily under general anesthesia.2 Although anesthesia has been used since the 1840s,3 many anesthesiologists believe that we still do not have a full understanding of how anesthetics operate on the body. Anesthesia is still as much art as science. Daily, patients place their trust in anesthesia providers when they come to the OR.4

Your patients consider anesthesia to be a major risk of surgery4 and expect you to be their advocate by caring for their pre- and intraop needs and providing safe and effective care. This care is affected by anesthetics. This brings up several questions: How can you improve the safety of the surgical team? What type of anesthesia is generally used in the perioperative setting? What is your role during the administration of anesthesia?

This continuing education module discusses medications and anesthetics used in the clinical setting; anesthesia-related problems, such as aspiration, injection of bolus anesthetic agents and malignant hyperthermia; and the perioperative team member’s role in dealing with these problems.

The Debut of Ether

The first documented successful use of anesthesia is attributed to William Morton, a dentist at Boston’s Massachusetts General Hospital. In 1846, Morton demonstrated that ether induced a lack of feeling of pain. At this time, physician and author Oliver Wendell Holmes Sr. coined the term anesthesia (from the Greek: an, “without,” and aisthesis, “perception”) to describe the new method of helping patients undergo surgical procedures without the perception of pain. Gone were the days of using opium and alcohol as anesthesia, with their adverse effects of vomiting and even death. The new discovery led to more invasive procedures with greater success and fewer deaths. By 1878, anesthesia with the use of an orotracheal tube was perfected. In 1898, the first spinal anesthetic was successfully administered. Today, technological advances in anesthesia have allowed patients to undergo more extensive procedures without pain, with fewer adverse effects and with no recall of the event (amnesia).4,5

The Setting

Anesthesia is provided in hospital ORs and outpatient facilities such as surgery centers and physicians’ offices. In such settings, the perioperative nurse acts as a patient advocate and caregiver and assists the anesthesia providers — the anesthesiologist or certified registered nurse anesthetist or the new anesthesia person on the scene, the anesthesia assistant — in providing safe and effective care before, during and immediately after a procedure. To be an effective member of the surgical team, the nurse must be knowledgeable about anesthesia, including how it works and how to help provide the best care to the patient.4

Before Surgery

All surgical procedures pose a risk. Therefore, patients should be in the best possible health before surgery. This optimal state of health includes both physical and psychological status. A patient’s physical and psychological status helps determine the events, issues and outcomes that will occur while the patient is anesthetized. The physical state of well-being can be determined by the health history, initial assessment and diagnostic testing. The baseline findings help the nurse formulate a plan of care with emphasis on an interprofessional approach. The team members include an anesthesiologist or a CRNA, who also performs assessments and documents his or her findings before moving the patient into the surgical area. Depending on the patient’s age, testing may include blood chemistry (such as a CBC), prothrombin time and partial thromboplastin time, an ECG and urinalysis.5 PT and PTT are done to evaluate the blood for its ability to clot and determine any clotting disorders. It is often done before surgery to evaluate how likely the patient is to have a bleeding or clotting problem during or after surgery. Urinalysis is used to detect urinary tract infections, metabolic disorders or kidney disorders.

An assessment and preoperative patient education may determine the patient’s psychological status. At this time, the nurse may discover that the patient has fears about the upcoming surgery. In rare cases (just 0.1% to 0.2% of patients5), awareness, also known as intraoperative awareness, has been reported, with 1% to 1.5% of cases of awareness occurring in high-risk surgical patients, such as those undergoing major trauma and cardiac procedures.4 Years ago, little monitoring equipment was available to alert the anesthesia provider to whether the patient was aware of the procedure being performed. Today, the Bispectral Index System can help the anesthesia provider monitor the optimal anesthesia level during general anesthesia and, to a lesser extent, the actual analgesia level.4,5 The system uses five electrodes on the patient’s forehead to measure the effects of specific anesthetic drugs on the brain and to track changes in the patient’s level of hypnosis (i.e., the altered state of consciousness or level of sedation).4,5

Before surgery, the perioperative nurse prepares the patient by completing the preop checklist, reviewing the patient’s chart and labs, and verifying the procedure by reviewing the informed consent with the patient, which names the procedure to be performed. Other nursing responsibilities include ensuring that the physician has obtained a consent, ascertaining the patient’s level of understanding with the use of teach-back to repeat the patient’s understanding of the instructions and consent,6 reinforcing teaching, answering questions and identifying any patient allergies, implants and issues with previous surgical procedures. This culminates with formulating the plan of care.

At this time, the anesthesia provider discusses the anesthesia options with the patient and classifies the patient into one of six groups that determine physical status.4,5,7-9 The anesthesia provider may use premedication, such as midazolam (Versed), to reduce the patient’s anxiety and provide amnesia.10 Other medications may include atropine to control secretions, metoclopramide (Reglan) to reduce nausea and vomiting and an antacid or H2-receptor-blocking agent such cimetidine (Tagamet) to reduce gastric production or decrease the acidity of gastric contents.4

During

Once all is ready, the patient is brought into the OR, providing time for the perioperative team member to focus on allaying the patient’s fears. Because the room is kept cold, the nurse places a warm blanket on the patient and secures a safety belt around the lower thigh. Body blanket warmers replace warm blankets in many ORs. Before placing ECG leads or a pulse oximeter on the patient, the nurse should explain its use. A calm, quiet environment is essential to an anesthetic induction. The nurse stands by to assist as the anesthesia provider uses a general anesthetic or starts an IV. Propofol (Diprivan), midazolam and thiopental (Pentothal) have been used. However, Pentothal now has been removed from the market.9

Muscle relaxants and analgesics are given during the procedure. Gases and vapors, such as desflurane (Suprane) and sevoflurane (Ultane), may also be used during induction.5 Although nitrous oxide may be used for maintenance, it has several adverse effects.10 Other measures, such as the application of cricoid pressure, may be required during induction. Cricoid pressure is applied using the thumb and index finger to provide downward pressure on the cricoid cartilage to prevent aspiration during induction. Opioids are given to alter the response to pain and reduce the sensation of pain. This is done without altering the other sensory responses. Fentanyl (Sublimaze) and other opioids have the adverse effects of nausea, vomiting and respiratory depression, which must be closely monitored to ensure patient safety.4,5 Titration of medication and use of the Bispectral Index System for individualized administration have reduced nausea and vomiting.4

With general or regional anesthesia or sedation, a safe and adequate amnesia and anesthesia and immobility are the anesthesia provider’s overall goals.4,10

How Does General Anesthesia Work?

General anesthesia is administered via inhalation, IV or both. Although it is not fully understood, general anesthesia is explained by several theories.

The unitary theory, which correlates to the Meyer-Overton theory, states that all anesthetics work through a common mechanism in which they dissolve into nerve-cell membranes and produce structural change, such as membrane swelling, that depresses channels, receptors and enzymes involved in sending nerve signals. The theory is correlated to how well anesthetics dissolve in lipids, as noted a century ago, but does not completely explain the actions of anesthesics.4

Protein receptor theory suggests specific central nervous system proteins serve as receptor cites, which must be occupied before the patient is unable to move.4

In addition, endogenous endorphins suppress pain pathways. However, this does not explain the full extent of anesthesia achieved when inhaled anesthetics are administered.4

Anesthesia is safer than it was years ago, given the current use of monitors for the heart and the brain as well as discovery of new anesthetic agents. Much is known, but more research is needed to understand what is occurring when a patient is under anesthesia.4

Evidence-Based Practice

Researchers are discovering more information about anesthesia.

Researchers have found that patients did not generally want a “support person” present during induction, as previous research had found. The support person, usually a family member, was thought to lower patient anxiety, thus promoting wound healing and lowering of postop pain. In addition, researchers discovered that having a support person disrupts the surgical team.11 Not so for pediatric patients, wherein presence of a parent during induction may alleviate anxiety.12

A study of anesthesia adverse events found that general anesthesia has a higher rate of adverse events in inpatients than outpatients. For outpatients, regional and general anesthesia had the highest rate of adverse events. Adverse events such as airway complications were more prevalent, and the researchers recommended that general anesthesia be more carefully monitored.13

The Three Phases

The administration of anesthesia has three phases: induction, maintenance and emergence.

Induction begins when the anesthetic is administered and ends when the incision is made. Anxiety-relieving medications such as midazolam block memory of the procedure while propofol, a rapid-acting medication, induces unconsciousness. Elderly patients or those with myocardial impairments receive etomidate (Amidate).10 During this phase, an endotracheal tube or a laryngeal mask airway may be inserted to maintain the airway and prevent aspiration. At this time, verification of the ETT placement is done by continuous capnography (endtital CO2 [ETCO2] monitoring) and checking of vital signs and breath sounds to ensure proper tube placement.10 Neuromuscular blocking agents or muscle relaxants such as succinylcholine (Anectine, Quelicin), atracurium (Tracrium) or rocuronium (Zemuron) are used to facilitate exposure of the surgical site and help with intubation.5,8

The nurse is responsible for maintaining vigilance for complications, such as aspiration during a rapid-sequence intubation. The anesthesia provider may need help during intubation to apply cricoid pressure, maintain an open airway or access additional supplies. Suction must be available to help remove any secretions that may obstruct vision during intubation. The nurse or surgical technologist may also serve as an additional set of eyes and ears alert for unanticipated events.

The maintenance phase begins with the surgical incision and ends near the completion of the procedure. Gases such as isoflurane (Forane), sevoflurane (Ultane) and desflurane (Suprane) are used for maintenance. Dexmedetomidine (Precedex) is becoming more common as a sedation agent and a supplement to general anesthesia.10 During this phase, the anesthesia provider maintains the level of anesthesia, monitors vital functions and provides sedation. The anesthesia provider may not require assistance from the nurse. Best practice dictates that the team remains alert to the possibility that additional items may be needed. An unanticipated need for medication or supplies unavailable in the anesthesia cart may arise. Usually, no emergent needs come up. At this time, the perioperative nurse may update the patient’s record.

The emergence phase starts at the patient’s wakening and ends when the patient is transferred to the PACU. Reversal drugs may be used or the patient may be allowed to wake up as the medication wears off. The patient must be observed during this time. Researchers have found that women wake up four minutes sooner than men from general anesthesia and may require earlier interventions,14 such as support and reassurance to help them deal with emergence delirium.

Emergence delirium occurs in greater frequency in the elderly and children.15 It is characterized by excitement followed by disorientation, kicking and screaming. Flailing and agitation are common, especially in children. Emergence delirium can be easily managed as the team works together to help with extubation and in emergence from general anesthesia.16

Regional Anesthesia

Patients who cannot tolerate general anesthesia or who undergo procedures such as surgery on extremities have alternatives such as regional anesthesia or local anesthesia with moderate sedation. The anesthesia provider administers regional anesthesia by injecting a local anesthetic along a nerve pathway into clusters of nerves supplying an area that needs numbing.14 The advantage of this agent is that it suppresses the pain impulse without causing a generalized depression of the entire nervous system. These anesthetics include eye block, epidural block, lower and upper extremity block and spinal block. The nurse helps the anesthesia provider with positioning the patient to facilitate the procedure. The drugs of choice include tetracaine (Viractin), lidocaine (Xylocaine), bupivacaine (Marcaine) and chloroprocaine (Nesacaine). Their use is based on the type and length of the procedure.4

The anesthesia provider typically uses an IV regional anesthetic called a Bier block to anesthetize the upper extremity, but a Bier block can also be used on the lower extremity. The anesthesia provider uses a double tourniquet and inserts an IV catheter in the operative arm (avoiding the surgical site). The arm is raised and exsanguinated. The proximal tourniquet cuff is inflated, and local anesthetic is injected into the IV catheter. If the patient feels discomfort, the distal cuff (the one over the injected area) is inflated, and the proximal cuff is deflated. This maneuver ensures the anesthetic remains in place until the tourniquet is deflated. The anesthesia provider and the perioperative nurse monitor the tourniquet inflation time and tell the surgeon the number of minutes the tourniquet has been in place. Lidocaine, bupivacaine, chloroprocaine, ropivacaine (Naropin) or mepivacaine (Carbocaine) is used, and the patient is observed for reactions such as toxicity or overdose.8 The tourniquet is deflated slowly to reduce the possibility of a bolus of local anesthetic entering the systemic circulation. Another method to reduce risks is to deflate the cuff for several seconds during planned cycles at the end of the procedure. A sentinel event can occur when an unexpected loss of anesthesia due to loss of tourniquet pressure exists with a toxic reaction.4,17

OR Today | Continuing Education | Anesthesia in the Perioperative SettingDuring a spinal block, the anesthesia provider injects anesthesia into the fluid surrounding the spinal cord. The anesthesia works quickly to numb the entire lower body; however, it cannot be adjusted like an epidural. The nurse or the nursing assistant may help reassure the patient while providing support for positioning during administration. The patient is observed for hypotension after successful anesthesia. Another complication is a high spinal block (a too high level of block), which can cause depression of the spinal cord and brainstem, resulting in respiratory and cardiac depression. In this case, artificial breathing and maintenance of blood pressure may be required. One complication not as common as in the past is spinal headache. Typically, it is seen in patients under age 40. The size of the hole left by the needle puncture of the dura is often responsible for this problem.4,10

In epidural anesthesia, medication is injected into the epidural space, which is bordered by two adjacent vertebrae, the ligamentum flavum and the dura, that lie just outside the spinal cord. Local anesthetics can be injected in the lumbar, cervical or thoracic region. A catheter may be secured in place for hours or days, and medications are regulated to control postop pain. For caudal anesthesia, the epidural space is approached through the caudal canal in the sacrum. It requires a greater amount of anesthetic to fill the epidural space. Caudal anesthesia is often used for pediatric surgery, on the perineum, and in the lower extremities.

Accidental dural puncture may cause an intense, incapacitating headache. Treatment is similar to spinal headache and may require strict bed rest, injection of autologous blood into the epidural space (an epidural blood patch), hydration, abdominal binders and caffeine.4 Vascular injection of local anesthetic may cause cardiac arrest, hypotension, confusion or tachycardia. In such circumstances, the patient may receive a benzodiazepine as well as ephedrine or phenylephrine. Anesthesia providers try to avoid adverse events from vascular injection of local anesthetics by using a test dose of local anesthetic with epinephrine to check for spinal or intravascular injection.4

Moderate Sedation

Also called conscious analgesia, moderate sedation is the administration of IV sedatives by a registered nurse who has special training in the administration of the medication and patient monitoring. Best practice dictates that the nurse administering sedation should have no other duties except to administer medication and monitor the patient.18 Medications such as diazepam (Valium), midazolam and fentanyl are used to provide sedation and analgesia. Monitoring equipment includes a blood pressure device, ECG machine, pulse oximeter, and suction and oxygen supplies. Emergency resuscitative equipment, such as medications, artificial airways, suction supplies and a defibrillator, should be readily available.5,8

Malignant Hyperthermia

Certain patients may have a genetic predisposition that limits the types of anesthesia that they can safely receive. For example, anesthesia agents such as halothane (Fluothane) and succinylcholine chloride can trigger malignant hyperthermia in some patients.5,8,13 MH is a rare, genetic disorder that occurs as a result of a hypermetabolic state, which increases carbon dioxide production, oxygen consumption and muscle membrane destruction. The key characteristics of this life-threatening complication are muscle rigidity, tachycardia, fever, hyperkalemia, myoglobinuria and acidosis.16 An elevation of body temperature is a late manifestation. If a patient has a family history of anesthesia problems and MH is suspected, the anesthesia provider uses nontriggering agents such as propofol (Diprivan).5,8,13,16

Safe Anesthetic Agents for MH Patients19

• Diazepam (Valium)

• Etomidate (Amidate)

• Hexobarbital (Evipal)

• Ketamine (Ketalar)

• Methohexital (Brevital)

• Pentobarbital (Nembutal)

• Propofol (Diprivan)

• Nitrous oxide

• Amethocaine (Pontocaine)

• Articaine (Septocaine)

• Bupivacaine (Sensorcaine)

• Etidocaine (Duranest)

• Lidocaine (Xylocaine)

Dantrolene sodium (Dantrolene) is seen as a life-saving treatment for MH episodes. This drug relaxes the skeletal muscle and may inhibit muscle contraction.16 Dantrolene sodium for injection (Dantrium IV) may be used because of the ease of mixing.20

During a crisis, the nurse and surgical technologist play a vital role in helping anesthesia providers mix and administer dantrolene sodium, cool the patient, insert a urinary catheter, draw arterial blood gases and other blood work, help with nasogastric tube lavage and obtain urine. Two decades ago, this crisis had a low survival rate, with up to 80% mortality. Today, the outcome from an MH crisis is more likely to be successful, with less than 5% mortality rate.21

The perioperative nurse and surgical technologist are an integral part of the healthcare team before, during and after surgical procedures. As team members, they need to be familiar with the theories and principles of anesthesia, anesthesia medications and possible complications of these medications. Knowledge of anesthesia and simulations and drills to prepare staff to respond to untoward events, such as an MH crisis, will help provide a safe and effective experience for the surgical patient in addition to supporting optimal practice and positive patient outcomes. The perioperative team member as an advocate of the patient can be more effective as a result of being competent in providing safe, optimal care.

Sophia Mikos-Schild, RN, EdD, MSN, MAM/HROB, CNOR, is Magnet coordinator at Presence St. Mary and Elizabeth Medical Center in Chicago. She is also an educator, a program developer, a faculty member of several online nursing programs and an author.

Inpatient surgery. Centers for Disease Control and Prevention Web site. http://www.cdc.gov/nchs/fastats/insurg.htm. Updated May 30, 2013. Accessed May 6, 2014.

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