Your patients expect you to be their advocate not only by caring for their pre- and intraop needs, but also by providing safe and effective care. Your patients expect you to be their advocate in providing safe and effective care. This care is affected by the presence of anesthetics. This brings up several questions: How can you improve the safety of the surgical team? What type of anesthesia is commonly used in the perioperative setting? What is your role in terms of anesthesia in the perioperative setting?

This module discusses medications and anesthetics used in the clinical setting. Anesthesia-related problems, such as aspiration, injection of bolus anesthetic agents, and malignant hyperthermia are identified, as is the nurse’s role during these situations.

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. It’s at this time that poet and physician 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 with the perception of pain and other sensations blocked. 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 the development of 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, further 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).²

The setting

Anesthesia is provided in hospital ORs and outpatient facilities, such as outpatient surgery centers and physician offices.  In such settings, the perioperative nurse not only acts as a patient advocate and caregiver, but also assists the anesthesia providers (the anesthesiologist or certified registered nurse anesthetist [CRNA]) 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, its action, and how to assist in providing the best care to the patient.² 

Before surgery

All surgical procedures pose a risk. Therefore, patients should be in the best possible state of 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 a multidisciplinary approach. The team members include an anesthesiologist or a CRNA, who also perform assessments and document his or her findings before moving the patient into the surgical area. Depending on the age of the patient, testing may include a CBC, prothrombin time (PT) and partial thromboplastin time (PTT), an ECG, and urinalysis (UA).³

An assessment and patient education session may determine the patient’s psychological status. At this time, the nurse may discover that the patient has fears about the upcoming surgery. As many as 40,000 patients a year in the United States experience full awareness during surgery even though they are given general anesthesia.¹ Years ago, little monitoring equipment was available to alert the anesthesia provider as 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.^1-3 The BIS uses five electrodes placed 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.^1-3 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, 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.3 (See sidebar.) The anesthesia provider may use premedication, such as midazolam (Versed), to reduce the patient’s anxiety and provide amnesia. Other medications may include atropine to control secretions, metoclopramide (Reglan) to reduce nausea and vomiting, and cimetidine (Tagamet) to reduce gastric production or decrease the acidity of gastric contents.²

During

Once all is ready, the patient is brought into the OR, providing time for the nurse to focus on allaying the patient’s fears. Because the room is kept cold, a warm blanket is placed on the patient while a safety belt is secured around the lower thigh. Before placing ECG leads or a pulse oximeter on the patient, the nurse should explain their 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, or thiopental (Pentothal) may be used. Muscle relaxants and analgesics are given during the procedure. Gases and vapors, such as nitrous oxide (N2 0), halothane (Fluothane), and sevoflurane (Ultane), may also be used during induction. 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 decrease the sensation of pain. This is accomplished 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.^{2, 3}

With general or regional anesthesia or sedation, a safe and adequate amnesia and anesthesia are the overall goals of the anesthesia provider.²

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 two main theories: “unitary” theory, which correlates to the Meyer-Overton theory, and the multisite agent-specific (MAS) theory. The unitary 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 depress 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. The Meyer-Overton theory is still considered a viable explanation, although today there are compounds that are not based on lipid solubility.^2,4 

The MAS theory suggests that more sites and mechanisms of action are involved in anesthetics, and different anesthetics can have varying effects on each site. This is proven by electroencephalograms that show different patterns depending on whether barbiturates or benzodiazepines are used. Additionally, the two drug classes have different neurotransmitter and clinical effects. Differences in recall, consciousness, and memory have been observed.

Anesthesia is safer than it was years ago with 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.^2,4,5

The three phases

The administration of anesthesia is divided into 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. During this phase an endotracheal tube (ET) or a laryngeal mask airway (LMA) may be inserted to maintain the airway and prevent aspiration. 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 assist in intubation.^6-8

It’s the nurse’s responsibility to maintain vigilance for possible complications. The anesthesia provider may need assistance during intubation to apply cricoid pressure, maintain an open airway, or make available additional supplies. Suction must be available to assist in removal of any secretions that may obstruct vision during intubation. The nurse may also serve as an additional set of eyes and ears on the 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, and desflurane (Suprane), are used for maintenance. 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 a state of vigilance is maintained by the team if additional items are needed. An unanticipated need for medication or supplies unavailable in the anesthesia cart may arise during this time. Usually, no emergent needs come up. At this time, the perioperative nurse may update the patient’s record.⁹

The emergence phase starts at the wakening of the patient and ends when the patient is transferred to the postprocedure unit. Reversal drugs may be used, or the patient may be allowed to wake up as the medication wears off. The patient needs to be observed during this time. In 1999, researchers found that women wake up four minutes sooner than men from general anesthesia and may require earlier interventions,⁴ such as support and reassurance in response to the patient’s flailing and agitation, which are common in emergence delirium. Emergence delirium is characterized by excitement followed by disorientation, kicking, and screaming. Emergence delirium can be easily managed as the team works together to assist in extubation and in emergence from general anesthesia.⁹

Regional anesthesia

Patients who cannot tolerate general anesthesia or who undergo procedures such as surgery on extremities have alternatives to general anesthesia, such as regional anesthesia or local anesthesia with conscious sedation. Regional anesthesia is administered by injecting a local anesthetic along a nerve pathway into clusters of nerves supplying an area that needs numbing.⁴ These anesthetics include eye block, epidural block, lower and upper extremity block, and spinal block. The nurse assists the anesthesia provider with positioning the patient to facilitate the procedure. The drugs of choice include tetracaine (Viractin), lidocaine (Xylocaine), bupivacaine (Marcaine), and chloroprocaine (Procaine). Their use is based on the type and length of the procedure.²

An IV regional anesthetic commonly called a Bier block is typically used to anesthetize the upper extremity but 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 then 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 (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 communicate with the surgeon as to the number of minutes the tourniquet has been in place. Lidocaine is used, and the patient is observed for reactions, such as toxicity or overdose. The tourniquet is deflated slowly to reduce the possibility of a bolus of local anesthetic entering the systemic circulation. Another method used 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.^2,10

Spinal anesthesia

During a spinal block, anesthesia is injected into the fluid surrounding the spinal cord. It works quickly to numb the entire lower body but can’t 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 other complication that does not occur as often as it once did is spinal headache. Typically, it is seen in patients less than 40 years old.  The size of the hole left by the needle puncture of the dura is often responsible for this problem.²

Epidural and caudal anesthesia

In epidural anesthesia, medication is injected into the epidural space, which is bordered by two adjacent vertebrae, the ligamentum flavum, and the dura, which lies just outside the spinal cord. The local 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 headache that may be incapacitating. Treatment is similar to spinal headache and may require strict bed rest, injection of autologous blood (an epidural blood patch), hydration, abdominal binders, and caffeine.² Vascular injection of local anesthetic may cause cardiac arrest, hypotension, convulsions, or tachycardia. In such circumstances, thiopental sodium (Pentothal) or a benzodiazepine may be given as well as ephedrine or phenylephrine. Adverse events from vascular injection of local anesthetics are usually prevented by using a test dose of local anesthetic with epinephrine to check for spinal or intravascular injection.²

Moderate sedation

Also called conscious analgesia, moderate sedation is the administration of IV sedatives by the registered nurse who has received special training in the administration of the medication and monitoring of the patient. Best practice dictates that the nurse administering sedation should have no other duties except to administer medication and monitor the patient.⁶ Medications such as diazepam (Valium), midazolam, fentanyl, and meperidine hydrochloride (Demerol) 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.⁶  

Malignant hyperthermia

Certain patients may have a genetic predisposition that limits the types of anesthesia that can be safely used.

Malignant hyperthermia (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 tachycardia, dysrhythmias, fever, hyperkalemia, myoglobinuria, and acidosis. An elevation of body temperature is a late manifestation of the complication. Research shows that some agents used in anesthesia (e.g., halothane, suxamethonium chloride) can trigger an episode. If a family history of anesthesia problems is reported and MH is suspected, nontriggering agents such as Propofol (Diprivan) are used.^3,8,10,11

Dantrolene sodium (Dantrolene) is seen as a life-saving treatment for MH episodes. During a crisis, the nurse plays a vital role in helping anesthesia providers mix and administer dantrolene sodium, cool the patient, insert a urinary catheter, draw arterial blood gases (ABGs) and other blood work, assist in 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 a MH crisis is more likely to be successful, with only a 10% mortality rate. Dantrolene sodium may be administered prophylactically and with other treatments, thus improving the outcome from an MH crisis.^2,7,10

The perioperative nurse is an integral part of the healthcare team before, during, and after surgical procedures. As a team member, the nurse needs to be familiar with the theories and principles of anesthesia, anesthesia medications, and possible complications of these medications. Knowledge of anesthesia and the ability to respond to untoward events will help provide a safe and effective experience for the surgical patient in addition to supporting optimal practice. The nurse as an advocate of the patient can be more effective as a result of being competent in providing optimal care.