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surgical team consists of the patient, the anesthesiologist or anesthetist, the surgeon, nurses, and the surgical technologists. The anesthesiologist or anesthetist (usually a nurse anesthetist) administers the anesthetic agent and monitors the patient's physical status throughout the surgery. The surgeon and assistants scrub and perform the surgery. The person in the scrub role, either a nurse or a surgical technologist, provides sterile instruments and supplies to the surgeon during the procedure. The circulating nurse coordinates the care of the patient in the OR. Care provided by the circulating nurse includes assisting with patient positioning, preparing the patient's skin for surgery, managing surgical specimens, and documenting intraoperative events
Gerontologic surgical considerations
- Elderly patients face higher risks from anesthesia and surgery than younger adult patients do
- Biologic variations of particular importance include age-related cardiovascular and pulmonary changes. The aging heart and blood vessels have decreased ability to respond to stress. Reduced cardiac output and limited cardiac reserve make the elderly patient vulnerable to changes in circulating volume and blood oxygen levels. Excessive or rapid administration of intravenous (IV) solutions can cause pulmonary edema. A sudden or prolonged decline in blood pressure may lead to cerebral ischemia, thrombosis, embolism, infarction, and anoxia. Reduced gas exchange can result in cerebral hypoxia.
- elderly patient needs fewer and smaller amounts of anesthetic agents to produce anesthesia and eliminates the anesthetic agent over a longer period of time, compared with a younger patient (Yellen, 2003). With increasing age, there is a decrease in the percentage of lean body tissue and a steady increase in fatty tissue (from 20 to 90 years of age). Anesthetic agents that have an affinity for fatty tissue concentrate in body fat and the brain. Lower doses of anesthetic agents are appropriate in an elderly patient if the patient is malnourished and has low plasma protein levels (Williams & Barbul, 2003). With decreased plasma proteins, more of the anesthetic agent remains free or unbound, and the result is more potent action.
- In addition, body tissues of the older adult are made up predominantly of water, and those tissues with a rich blood supply, such as skeletal muscle, liver, and kidneys, shrink. Reduced liver size decreases the rate at which the liver can inactivate many anesthetic agents, and decreased kidney function slows the elimination of waste products and anesthetics. Other factors that affect the elderly surgical patient in the intraoperative period include the following:
Impaired ability to increase metabolic rate and impaired thermoregulatory mechanisms increase susceptibility to hypothermia.
Bone loss (25% in women, 12% in men) necessitates careful manipulation and positioning during surgery.
Reduced ability to adjust rapidly to emotional and physical stress influences surgical outcomes and requires meticulous observation of vital functions.
a state of narcosis, analgesia, relaxation, and loss of reflexes
physician trained to deliver anesthesia and to monitor the patient's condition during surgery
the substance, such as a chemical or gas, used to induce anesthesia
health care professional, such as a nurse anesthetist, who is trained to deliver anesthesia and to monitor the patient's condition during surgery
circulating nurse (or circulator)
registered nurse who coordinates and documents patient care in the operating room
use of sedation to depress the level of consciousness without altering the patient's ability to maintain a patent airway and to respond to physical stimuli and verbal commands, previously referred to as conscious sedation
monitored anesthesia care (MAC)
moderate sedation administered by an anesthesiologist or anesthetist
area in the operating room where scrub attire and surgical masks are required; includes operating room and sterile core areas
registered nurse, licensed practical nurse, or surgical technologist who scrubs and dons sterile surgical attire, prepares instruments and supplies, and hands instruments to the surgeon during the procedure
area in the operating room where scrub attire is required; may include areas where surgical instruments are processed
absence of microorganisms in the surgical environment to reduce the risk for infection
area in the operating room that interfaces with other departments; includes patient reception area and holding area
- circulating nurse (also known as the circulator) is preferably a registered nurse (RN). In 20 states in the United States, the circulator is required by law to be an RN (Phillips, 2004). He or she manages the OR and protects the patient's safety and health by monitoring the activities of the surgical team, checking the OR conditions, and continually assessing the patient for signs of injury and implementing appropriate interventions. Main responsibilities include verifying consent; coordinating the team; and ensuring cleanliness, proper temperature, humidity, lighting, safe function of equipment, and the availability of supplies and materials. The circulating nurse monitors aseptic practices to avoid breaks in technique while coordinating the movement of related personnel (medical, x-ray, and laboratory), as well as implementing fire safety precautions. The circulating nurse also monitors the patient and documents specific activities throughout the operation to ensure the patient's safety and well-being.
- In addition, the circulating nurse is responsible for ensuring that the second verification of the surgical procedure and site takes place and is documented (see Fig. 18-4 in Chapter 18). In some institutions, this is referred to as a “surgical or preprocedure pause” or “time-out” that takes place among the surgical team prior to incision.
- scrub role include performing a surgical hand scrub; setting up the sterile tables; preparing sutures, ligatures, and special equipment (eg, laparoscope); and assisting the surgeon and the surgical assistants during the procedure by anticipating the instruments and supplies that will be required, such as sponges, drains, and other equipment. As the surgical incision is closed, the scrub person and the circulator count all needles, sponges, and instruments to be sure they are accounted for and not retained as a foreign body in the patient
- sponge counts to take place at the beginning of surgery and twice at the end. Tissue specimens obtained during surgery are labeled by the scrub person and sent to the laboratory by the circulator.
surgeon performs the surgical procedure and heads the surgical team. He or she is a licensed physician (MD), osteopath (DO), oral surgeon (DDS or DMD), or podiatrist (DPM) who is specially trained and qualified.
Registered Nurse First Assistant
RNFA responsibilities may include handling tissue, providing exposure at the operative field, suturing, and maintaining hemostasis (Rothrock, 2003). The role requires a thorough understanding of anatomy and physiology, tissue handling, and the principles of surgical asepsis. The RNFA must be aware of the objectives of the surgery, must have the knowledge and ability to anticipate needs and to work as a skilled member of a team, and must be able to handle any emergency situation in the OR.
Anesthesiologist and Anesthetist
- anesthesiologist is a physician specifically trained in the art and science of anesthesiology. An anesthetist is a qualified health care professional who administers anesthetics.
- anesthesiologist or anesthetist assesses the patient before surgery, selects the anesthesia, administers it, intubates the patient if necessary, manages any technical problems related to the administration of the anesthetic agent, and supervises the patient's condition throughout the surgical procedure
American Society of Anesthesiologists Physical Status Classification System
describe the patient's general status and identify potential risks during surgery. There are six classes of physical status.
- P1. A normal healthy patient
- Example: No systemic abnormality, localized infection without fever, benign tumor, hernia
- P2. A patient with mild systemic disease, without functional limitations
- Example: Well-controlled hypertension, well-controlled diabetes mellitus, chronic bronchitis, obesity, age over 80 years
- P3. A patient with severe systemic disease associated with functional limitations
- Example: Severe disease, compensated heart failure, myocardial infarction more than 6 months ago, angina pectoris, severe dysrhythmia, cirrhosis, poorly controlled diabetes or hypertension, ileus
- P4. A patient with an incapacitating systemic disease that is a constant threat to life
- Example: Severe heart failure, myocardial infarction less than 6 months ago, severe respiratory failure, advanced liver or renal failure
- P5. A moribund patient who is not expected to survive for 24 hours with or without operation
- Example: Unconscious patient with traumatic head injury and agonal respirations
P6. Patient is brain dead and is being prepared as an organ donor
Zones in OR
To help decrease microbes, the surgical area is divided into three zones: the unrestricted zone, where street clothes are allowed; the semirestricted zone, where attire consists of scrub clothes and caps; and the restricted zone, where scrub clothes, shoe covers, caps, and masks are worn. The surgeons and other surgical team members wear additional sterile clothing and protective devices during the operation.
The basic principles of aseptic technique
All materials in contact with the surgical wound or used within the sterile field must be sterile. Sterile surfaces or articles may touch other sterile surfaces or articles and remain sterile; contact with unsterile objects at any point renders a sterile area contaminated.
Gowns of the surgical team are considered sterile in front from the chest to the level of the sterile field. The sleeves are also considered sterile from 2 inches above the elbow to the stockinette cuff.
Sterile drapes are used to create a sterile field. Only the top surface of a draped table is considered sterile. During draping of a table or patient, the sterile drape is held well above the surface to be covered and is positioned from front to back.
Items are dispensed to a sterile field by methods that preserve the sterility of the items and the integrity of the sterile field. After a sterile package is opened, the edges are considered unsterile. Sterile supplies, including solutions, are delivered to a sterile field or handed to a scrubbed person in such a way that the sterility of the object or fluid remains intact.
The movements of the surgical team are from sterile to sterile areas and from unsterile to unsterile areas. Scrubbed persons and sterile items contact only sterile areas; circulating nurses and unsterile items contact only unsterile areas.
Movement around a sterile field must not cause contamination of the field. Sterile areas must be kept in view during movement around the area. At least a 1-foot distance from the sterile field must be maintained to prevent inadvertent contamination.
Whenever a sterile barrier is breached, the area must be considered contaminated. A tear or puncture of the drape permitting access to an unsterile surface underneath renders the area unsterile. Such a drape must be replaced.
Every sterile field is constantly monitored and maintained. Items of doubtful sterility are considered unsterile. Sterile fields are prepared as close as possible to the time of use.
The routine administration of hyperoxia (high levels of oxygen) is not recommended to reduce surgical site infections. In a study of 165 patients undergoing general surgery, the rate of surgical site infection was higher in patients who received 80% oxygen during surgery than in those who received 35% oxygen
Anesthesia is a state of narcosis (severe central nervous system depression produced by pharmacologic agents), analgesia, relaxation, and reflex loss. Patients under general anesthesia are not arousable, not even to painful stimuli. They lose the ability to maintain ventilatory function and require assistance in maintaining a patent airway. Cardiovascular function may be impaired as well.
General anesthesia consists of four stages
Stage I: beginning anesthesia. As the patient breathes in the anesthetic mixture, warmth, dizziness, and a feeling of detachment may be experienced. The patient may have a ringing, roaring, or buzzing in the ears and, although still conscious, may sense an inability to move the extremities easily. During this stage, noises are exaggerated; even low voices or minor sounds seem loud and unreal. For this reason, unnecessary noises and motions are avoided when anesthesia begins.
Stage II: excitement. The excitement stage, characterized variously by struggling, shouting, talking, singing, laughing, or crying, is often avoided if the anesthetic is administered smoothly and quickly. The pupils dilate, but they contract if exposed to light; the pulse rate is rapid, and respirations may be irregular. Because of the possibility of uncontrolled movements of the patient during this stage, the anesthesiologist or anesthetist must always be assisted by someone ready to help restrain the patient. A strap may be in place across the patient's thighs, and the hands may be secured to an armboard. The patient should not be touched except for purposes of restraint, but restraints should not be applied over the operative site. Manipulation increases circulation to the operative site and thereby increases the potential for bleeding.
Stage III: surgical anesthesia. Surgical anesthesia is reached by continued administration of the anesthetic vapor or gas. The patient is unconscious and lies quietly on the table. The pupils are small but contract when exposed to light. Respirations are regular, the pulse rate and volume are normal, and the skin is pink or slightly flushed. With proper administration of the anesthetic, this stage may be maintained for hours in one of several planes, ranging from light (1) to deep (4), depending on the depth of anesthesia needed.
Stage IV: medullary depression. This stage is reached when too much anesthesia has been administered. Respirations become shallow, the pulse is weak and thready, and the pupils become widely dilated and no longer contract when exposed to light. Cyanosis develops and, without prompt intervention, death rapidly follows. If this stage develops, the anesthetic is discontinued immediately and respiratory and circulatory support is initiated to prevent death. Stimulants, although rarely used, may be administered; narcotic antagonists can be used if the overdosage is due to opioids.
Inhaled anesthetic agents
Inhaled anesthetic agents include volatile liquid agents and gases. Volatile liquid anesthetics produce anesthesia when their vapors are inhaled. Commonly used inhalation agents are included in Table 19-1. All are administered with oxygen and usually with nitrous oxide as well.
- Gas anesthetics are administered by inhalation and are always combined with oxygen. Nitrous oxide is the most commonly used gas anesthetic agent. When inhaled, the anesthetics enter the blood through the pulmonary capillaries and act on cerebral centers to produce loss of consciousness and sensation. When anesthetic administration is discontinued, the vapor or gas is eliminated through the lungs.
- The vapor from inhalation anesthetics can be administered to the patient by several methods. The inhalation anesthetic may be administered through an LMA (Fig. 19-1A), a flexible tube with an inflatable silicone ring and cuff that can be inserted into the larynx. The endotracheal technique for administering anesthetics consists of introducing a soft rubber or plastic endotracheal tube into the trachea, usually by means of a laryngoscope. The endotracheal tube may be inserted through either the nose (see Fig. 19-1B) or mouth (see Fig. 19-1C). When in place, the tube seals off the lungs from the esophagus so that, if the patient vomits, stomach contents do not enter the lungs.
TABLE 19-1 Inhalation Anesthetic Agents
- Halothane (Fluothane)
- Inhalation;special vaporizer
- Not explosive or flammableInduction rapid and smoothUseful in almost every type of surgeryLow incidence of postoperative nausea and vomiting
- Requires skillful administration to prevent over-dosageMay cause liver damageMay produce hypotensionRequires special vaporizer for administrationRespiratory depression
- In addition to observation of pulse and respiration postoperatively, blood pressure must be monitored frequently.
- Enflurane (Ethrane) Inhalation
- Rapid induction and recoveryPotent analgesicNot explosive or flammable
- Respiratory depression may develop rapidly, along with ECG abnormalities.Not compatible with epinephrine
- Observe for possible respiratory depression. Administration with epinephrine may cause ventricular fibrillation.
- Isoflurane (Forane) Inhalation
- Rapid induction and recoveryMuscle relaxants are markedly potentiated.
- A profound respiratory depressant
- Respirations must be monitored closely and supported when necessary.
- Sevoflurane (Ultrane)
- Rapid induction and excretion; minimal side effects
- Coughing and laryngospasm; trigger for malignant hyperthermia
- Monitor for malignant hyperthermia.
- Desflurane (Suprane) Inhalation
- Rapid induction and emergence; rare organ toxicity
- Respiratory irritation; trigger for malignant hyperthermia
- Monitor for malignant hyperthermia, dysrhythmias.
- Nitrous oxide (N2O) Inhalation (semiclosed method)
- Induction and recovery rapidNon flammableUseful with oxygen for short proceduresUseful with other agents for all types of surgery
- Poor relaxantWeak anestheticMay produce hypoxia
- Most useful in conjunction with other agents with longer actionMonitor for chest pain, hypertension, and stroke.
- Oxygen (O2) Inhalation
- Can increase O2 available to tissues
- High concentrations are hazardous
- Increased fire risk when used with lasers
TABLE 19-2 Commonly Used Intravenous Medications
- Common Usage
- Morphine sulfate (MS)
- Perioperative pain; premedication
- Inexpensive;duration of action 4 to 5 hours; euphoria;good cardiovascular stability
- Nausea and vomiting; histamine release; postural ↓BP and ↓SVR
- Used intrathecally and epidurally for postoperative pain; elimination half-life 3 hours
- Alfentanil (Alfenta)
- Surgical analgesia in ambulatory patients
- Duration of action 0.5 hour;used as bolus or infusion
Potency:750 µg =10 mg morphine sulfate; elimination half-life 1.6 hours
- Fentanyl (Sublimaze)
- Surgical analgesia: epidural infusion for postoperative analgesia;add to SAB
- Good cardiovascular stability;duration of action 0.5 hour
Most commonly used opioid; potency:100 µg =10 mg morphine sulfate; elimination half-life 3.6 hours
- Remifentanil (Ultiva) IV infusion for surgical analgesia;small boluses for brief, intense pain
- Easily titratable;metabolized by blood and tissue esterases;very short duration;good cardiovascular stability
- New;expensive; requires mixing; may cause muscle rigidity
- Potency:25 µg =10 mg morphine sulfate;20 to 30 times potency of alfentanil;elimination half-life 3 to 10 min
- Sufentanil (Sufenta)
- Surgical analgesia
- Good cardiovascular stability;duration of action 0.5 hour;prolonged analgesia
- Prolonged respiratory depression
- Potency:15 µg =10 mg morphine sulfate;elimination half-life 2.7 hours
Depolarizing Muscle Relaxants
- Succinylcholine (Anectine, Quelicin) Intubation;short cases
- Rapid onset;short duration
- Requires refrigeration; may cause fasciculations, postoperative myalgias, and dysrhythmias; ↓serum K+ with burns, tissue trauma, paralysis, and muscle diseases; slight histamine release
- Prolonged muscle relaxation with serum cholinesterase deficiency and certain antibiotics; trigger agent for malignant hyperthermia
Nondepolarizing Muscle Relaxants—Intermediate Onset and Duration
- Atracurium (Tracrium) Intubation;maintenance of relaxation
- No significant cardiovascular or cumulative effects;good with renal failure
- Requires refrigeration; slight histamine release
- Breakdown by Hofman elimination (non-enzymatic degradation)and ester hydrolysis
- Cisatracurium (Nimbex)
- Intubation;maintenance of relaxation
- Similar to atracurium
- No histamine release
- Similar to atracurium
- Mivacurium (Mivacron) Intubation;maintenance of relaxation
- Short acting;rapid metabolism by plasma cholinesterase;used as bolus or infusion
- Expensive in longer cases
- New;rarely need to reverse; prolonged effect with plasma cholinesterase deficiency
- Rocuronium (Zemuron)
- Intubation;maintenance of relaxation
- Rapid onset (dose-dependent);elimination via kidney and liver
- Vagolytic;may ↑HR
- Duration similar to atracurium and vecuronium
- Vecuronium (Norcuron)
- Intubation;maintenance of relaxation
- No significant cardiovascular or cumulative effects;no histamine release
- Requires mixing
- Mostly eliminated in bile, some in urine
Nondepolarizing Muscle Relaxants—Longer Onset and Duration
- Maintenance of relaxation
- May cause histamine release and transient ganglionic blockade
- Mostly used for pretreatment with succinylcholine
- Metocurine (Metubine)
- Maintenance of relaxation
- Good cardiovascular stability
- Slight histamine release
- Large bolus may cause ↓BP
- Pancuronium (Pavulon) Maintenance of relaxation
- May cause ↑HR and ↑BP
- Mostly renal elimination
- Etomidate (Amidate)
- Good cardiovascular stability;fast, smooth induction and recovery
- May cause pain with injection and myotonic movements
- Diazepam (Valium, Dizac)
- Amnesia;hypnotic; preoperative medication
- Good sedation
- Prolonged duration
- Residual effects for 20 to 90 hr;increased effect with alcohol
- Ketamine (Ketalar) Induction, occasional maintenance (IV or IM)
- Short acting;patient maintains airway;good in small children and burn patients
- Large doses may cause hallucinations and respiratory depression
- Need darkened, quiet room for recovery;often used in trauma cases
- Midazolam (Versed)
- Hypnotic;anxiolytic; sedation;often used as adjunct to induction
- Excellent amnesia; water-soluble (no pain with IV injection);short-acting
- Slower induction than thiopental
- Often used for amnesia with insertion of invasive monitors or regional anesthesia
- Propofol (Diprivan)
- Induction and maintenance; sedation with regional anesthesia or MAC
- Rapid onset;awakening in 4 to 8 min
- May cause pain when injected
- Short elimination half-life (34–64 min)
- Sodium methohexital (Brevital)
- Ultrashort-acting barbiturate
- May cause hiccups
- Can be given rectally
- Thiopental sodium (Pentothal)
- May cause laryngospasm;can be given rectally
- Large doses may cause apnea and cardiovascular depression
- General anesthesia can also be produced by the IV administration of various substances, such as barbiturates, benzodiazepines, nonbarbiturate hypnotics, dissociative agents, and opioid agents
- An advantage of IV anesthesia is that the onset of anesthesia is pleasant; there is none of the buzzing, roaring, or dizziness known to follow administration of an inhalation anesthetic. For this reason, induction of anesthesia usually begins with an IV agent and is often preferred by patients who have experienced various methods. The duration of action is brief, and the patient awakens with little nausea or vomiting.
- A disadvantage of an IV anesthetic such as thiopental (Pentothal) is its powerful respiratory depressant effect. It must be administered by a skilled anesthesiologist or anesthetist and only when some method of oxygen administration is available immediately in case of difficulty. Sneezing, coughing, and laryngospasm are sometimes noted with its use.
- IV neuromuscular blockers (muscle relaxants) block the transmission of nerve impulses at the neuromuscular junction of skeletal muscles. Muscle relaxants are used to relax muscles in abdominal and thoracic surgery, relax eye muscles in certain types of eye surgery, facilitate endotracheal intubation, treat laryngospasm, and assist in mechanical ventilation.
- Regional anesthesia is a form of local anesthesia in which an anesthetic agent is injected around nerves so that the area supplied by these nerves is anesthetized. The effect depends on the type of nerve involved. Motor fibers are the largest fibers and have the thickest myelin sheath. Sympathetic fibers are the smallest and have a minimal covering. Sensory fibers are intermediate. A local anesthetic blocks motor nerves least readily and sympathetic nerves most readily. An anesthetic cannot be regarded as having worn off until all three systems (motor, sensory, and autonomic) are no longer affected.
- The patient receiving regional anesthesia is awake and aware of his or her surroundings unless medications are given to produce mild sedation or to relieve anxiety. The nurse must avoid careless conversation, unnecessary noise, and unpleasant odors; these may be noticed by the patient in the OR and may contribute to a negative response to the surgical experience. A quiet environment is therapeutic. The diagnosis must not be stated aloud if the patient is not to know it at this time.
- Epidural anesthesia, a commonly used conduction block, is achieved by injecting a local anesthetic into the epidural space that surrounds the dura mater of the spinal cord (Fig. 19-2). (In contrast, spinal anesthesia involves injection through the dura mater into the subarachnoid space surrounding the spinal cord.) Epidural anesthesia blocks sensory, motor, and autonomic functions; it differs from spinal anesthesia by the site of the injection and the amount of anesthetic agent used. Epidural doses are much higher because the epidural anesthetic does not make direct contact with the spinal cord or nerve roots.
- advantage of epidural anesthesia is the absence of headache that occasionally results from spinal anesthesia. A disadvantage is the greater technical challenge of introducing the anesthetic into the epidural rather than the subarachnoid space. If inadvertent puncture of the dura occurs during epidural anesthesia and the anesthetic travels toward the head, high spinal anesthesia can result; this can produce severe hypotension and respiratory depression and arrest. Treatment of these complications includes airway support, IV fluids, and use of vasopressors.
- Spinal anesthesia is an extensive conduction nerve block that is produced when a local anesthetic is introduced into the subarachnoid space at the lumbar level, usually between L4 and L5 (see Fig. 19-2). It produces anesthesia of the lower extremities, perineum, and lower abdomen. For the lumbar puncture procedure, the patient usually lies on the side in a knee–chest position. Sterile technique is used as a spinal puncture is made and the medication is injected through the needle. As soon as the injection has been made, the patient is positioned on his or her back. If a relatively high level of block is sought, the head and shoulders are lowered.
- The spread of the anesthetic agent and the level of anesthesia depend on the amount of fluid injected, the speed with which it is injected, the positioning of the patient after the injection, and the specific gravity of the agent. If the specific gravity is greater than that of cerebrospinal fluid (CSF), the agent moves to the dependent position of the subarachnoid space. If the specific gravity is less than that of CSF, the anesthetic moves away from the dependent position. The anesthesiologist or anesthetist controls the spread of the agent. Table 19-3 contains types of regional anesthesia agents.
- A few minutes after induction of a spinal anesthetic, anesthesia and paralysis affect the toes and perineum and then gradually the legs and abdomen. If the anesthetic reaches the upper thoracic and cervical spinal cord in high concentrations, a temporary partial or complete respiratory paralysis results. Paralysis of the respiratory muscles is managed by mechanical ventilation until the effects of the anesthetic on the cranial and thoracic nerves have worn off.
- Nausea, vomiting, and pain may occur during surgery when spinal anesthesia is used. As a rule, these reactions result from manipulation of various structures, particularly those within the abdominal cavity. The simultaneous IV administration of a weak solution of thiopental and inhalation of nitrous oxide may prevent such reactions.
- Headache may be an after-effect of spinal anesthesia. Several factors are related to the incidence of headache: the size of the spinal needle used, the leakage of fluid from the subarachnoid space through the puncture site, and the patient's hydration status. Measures that increase cerebrospinal pressure are helpful in relieving headache. These include maintaining a quiet environment, keeping the patient lying flat, and keeping the patient well hydrated.
- In continuous spinal anesthesia, the tip of a plastic catheter remains in the subarachnoid space during the surgical procedure so that more anesthetic may be injected as needed. This technique allows greater control of the dosage, but there is greater potential for postanesthetic headache because of the large-gauge needle used.
TABLE 19-3 Selected Regional and Local Anesthetic Agents
- Lidocaine (Xylocaine)
- Epidural, spinal, peripheral intravenous anesthesia, and local infiltration
- RapidLonger duration of action (compared with procaine)Free from local irritative effect
- Occasional idiosyncrasy
- Useful topically for cystoscopyObserve for untoward reactions–drowsiness, depressed respiration, seizures
- Bupivacaine (Marcaine, Sensoricaine) Epidural, spinal, peripheral intravenous anesthesia, and local in filtration
- Duration is 2–3 times longer than lidocaine
- Use cautiously in patients with known drug allergies or sensitivities.
- A period of analgesia persists after return of sensation;therefore, need for strong analgesics is reduced.
- Tetracaine (Pontocaine)
- Topical, infiltration, and nerve block
- Long acting, produces good relaxation
- Occasional allergic reaction
- More than 10 times as potent as procaine (Novocaine)
- Procaine (Novocaine) Local infiltration
- Occasional allergic reaction
- Commonly used in oral or dental surgery
Local conduction blocks
Examples of common local conduction blocks are:
Brachial plexus block, which produces anesthesia of the arm
Paravertebral anesthesia, which produces anesthesia of the nerves supplying the chest, abdominal wall, and extremities
Transsacral (caudal) block, which produces anesthesia of the perineum and, occasionally, the lower abdomen
Moderate sedation (or moderate analgesia),
- previously referred to as conscious sedation, is a form of anesthesia that involves the IV administration of sedatives and/or analgesic medications to reduce patient anxiety and control pain during diagnostic or therapeutic procedures. It is being used increasingly for specific short-term surgical procedures in hospitals and ambulatory care centers (Rothrock, 2003). The goal is to depress a patient's level of consciousness to a moderate level to enable surgical, diagnostic, or therapeutic procedures to be performed while ensuring the patient's comfort during and cooperation with the procedures. With moderate sedation, the patient is able to maintain a patent airway, retain protective airway reflexes, and respond to verbal and physical stimuli (Morton, Fontaine, Hudak et al., 2005).
- Moderate sedation can be administered by an anesthesiologist, anesthetist, or other specially trained and credentialed physician or nurse. The patient receiving moderate sedation is never left alone and is closely monitored by a physician or nurse who is knowledgeable and skilled in detecting dysrhythmias, administering oxygen, and performing resuscitation. The continual assessment of the patient's vital signs, level of consciousness, and cardiac and respiratory function is an essential component of moderate sedation. Pulse oximetry, ECG monitor, and frequent measurement of vital signs are used to monitor the patient. The regulations for use and administration of moderate sedation differ from state to state, and its administration is addressed by standards issued by JCAHO and by institutional policies and nursing specialty organizations, including the Association of PeriAnesthesia Nurses (2004).
Monitored anesthesia care (MAC),
also referred to as monitored sedation, is administered by an anesthesiologist or anesthetist. Although similar to moderate sedation, the health care provider who administers MAC, usually an anesthesiologist or anesthetist, must be prepared and qualified to convert to general anesthesia if necessary. The skills of an anesthesiologist or anesthetist may be necessary to manage the effects of a level of deeper sedation to return the patient to the appropriate level of sedation (Morton et al., 2005; American Society of Anesthesiologists, 2004). MAC may be used for healthy patients undergoing relatively minor surgical procedures and for some critically ill patients who may be unable to tolerate anesthesia without extensive invasive monitoring and pharmacologic support (Rothrock, 2003). Moderate sedation and monitored anesthesia care are compared in Table 19-4.
Infiltration anesthesia is the injection of a solution containing the local anesthetic into the tissues at the planned incision site. Often it is combined with a local regional block by injecting the nerves immediately supplying the area. Advantages of local anesthesia are as follows:
It is simple, economical, and nonexplosive.
Equipment needed is minimal.
Postoperative recovery is brief.
Undesirable effects of general anesthesia are avoided.
- It is ideal for short and superficial surgical procedures.
- Local anesthesia is often administered in combination with epinephrine. Epinephrine constricts blood vessels, which prevents rapid absorption of the anesthetic agent
P.516and thus prolongs its local action. Rapid absorption of the anesthetic agent into the bloodstream, which could cause seizures, is also prevented. Agents that can be used as local anesthetic agents are listed in Table 19-3; some of the same agents used in regional anesthesia are used as local anesthetics.
- Local anesthesia is the preferred method of choice in any surgical procedure in which it can be used. However, contraindications include high preoperative levels of anxiety, because surgery with local anesthesia may increase anxiety. A patient who requests general anesthesia rarely does well under local anesthesia. For some surgical procedures, local anesthesia is impractical because of the number of injections and the amount of anesthetic that would be required (eg, breast reconstruction).
- The skin is prepared as for any surgical procedure, and a small-gauge needle is used to inject a modest amount of the anesthetic into the skin layers. This produces blanching or a wheal. Additional anesthetic is then injected into the skin until an area the length of the proposed incision is anesthetized. A larger, longer needle then is used to infiltrate deeper tissues with the anesthetic. The action of the agent is almost immediate, so surgery may begin as soon as the injection is complete. Anesthesia lasts 45 minutes to 3 hours, depending on the anesthetic and the use of epinephrine.
Monitored Anesthesia Care (MAC)
TABLE 19-4 Comparison of Moderate Sedation and Monitored Anesthesia Care
- Purposeful response to repeated or painful verbal or tactile stimulation
- Purposeful response after stimulation
- No intervention required
- Intervention may be required
- Spontaneous ventilation
- May be inadequate
- Cardiovascular function
- Usually maintained
- Usually maintained
Potential intraoperative complications
The surgical patient is subject to several risks. Potential intraoperative complications include nausea and vomiting, anaphylaxis, hypoxia, hypothermia, malignant hyperthermia, and disseminated intravascular coagulopathy (DIC).
Nausea and vomiting
- Nausea and vomiting, or regurgitation, may affect patients during the intraoperative period. If gagging occurs, the patient is turned to the side, the head of the table is lowered, and a basin is provided to collect the vomitus. Suction is used to remove saliva and vomited gastric contents. The advent of new anesthetics has reduced the incidence; however, there is no single way to prevent nausea and vomiting. An interdisciplinary approach involving the surgeon, anesthesiologist or anesthetist, and nurse is best.
- In some cases, the anesthesiologist or anesthetist administers antiemetics preoperatively or intraoperatively to counteract possible aspiration. If the patient aspirates vomitus, an asthma-like attack with severe bronchial spasms and wheezing is triggered. Pneumonitis and pulmonary edema can subsequently develop, leading to extreme hypoxia. Increasing medical attention is being paid to silent regurgitation of gastric contents (not related to preoperative fasting times), which occurs more frequently than previously realized. The volume and acidity of the aspirate determine the extent of damage to the lungs. Patients may be given Bicitra, a clear, nonparticulate antacid to increase gastric fluid pH or a histamine-2 (H2) receptor antagonist such as cimetidine (Tagamet), ranitidine (Zantac), or famotidine (Pepcid) to decrease gastric acid production
Any time the patient comes into contact with a foreign substance, there is the potential for an anaphylactic reaction. Because medications are the most common cause of anaphylaxis, intraoperative nurses must be aware of the type and method of anesthesia used as well as the specific agents. An anaphylactic reaction can occur in response to many medications, latex, or other substances. The reaction may be immediate or delayed. Anaphylaxis is a life-threatening acute allergic reaction. See Chapters 15 and 53 for more details about the signs, symptoms, and treatment of Fibrin sealants are used in a variety of surgical procedures, and cyanoacrylate tissue adhesives are used to close wounds without the use of sutures. These sealants have been implicated in allergic reactions and anaphylaxis (Phillips, 2004). Although these reactions are rare, the nurse must be alert to the possibility and observe the patient for changes in vital signs and symptoms of anaphylaxis when these products are used.
Hypoxia and Other Respiratory Complications
Inadequate ventilation, occlusion of the airway, inadvertent intubation of the esophagus, and hypoxia are significant potential complications associated with general anesthesia. Many factors can contribute to inadequate ventilation. Respiratory depression caused by anesthetic agents, aspiration of respiratory tract secretions or vomitus, and the patient's position on the operating table can compromise the exchange of gases. Anatomic variation can make the trachea difficult to visualize and result in the artificial airway's being inserted into the esophagus rather than into the trachea. In addition to these dangers, asphyxia caused by foreign bodies in the mouth, spasm of the vocal cords, relaxation of the tongue, or aspiration of vomitus, saliva, or blood can occur. Brain damage from hypoxia occurs within minutes; therefore, vigilant monitoring of the patient's oxygenation status is a primary function of the anesthesiologist or anesthetist and the circulating nurse. Peripheral perfusion is checked frequently, and pulse oximetry values are monitored continuously.
- During anesthesia, the patient's temperature may fall. Glucose metabolism is reduced, and, as a result, metabolic acidosis may develop. This condition is called hypothermia and is indicated by a core body temperature that is lower than normal (36.6°C [98.0°F] or less). Inadvertent hypothermia may occur as a result of a low temperature in the OR, infusion of cold fluids, inhalation of cold gases, open body wounds or cavities, decreased muscle activity, advanced age, or the pharmaceutical agents used (eg, vasodilators, phenothiazines, general anesthetics). Hypothermia may also be intentionally induced in selected surgical procedures (eg, cardiac surgeries requiring cardiopulmonary bypass) to reduce the patient's metabolic rate and energy demands (Seifert, 2002).
- Preventing unintentional hypothermia is a major objective. If hypothermia occurs, the goal of intervention is to minimize or reverse the physiologic process. If hypothermia is intentional, the goal is safe return to normal body temperature. Environmental temperature in the OR can temporarily be set at 25° to 26.6°C (78° to 80°F). IV and irrigating fluids are warmed to 37°C (98.6°F). Wet gowns and drapes are removed promptly and replaced with dry materials, because wet linens promote heat loss. Whatever methods are used to rewarm the patient, warming must be accomplished gradually, not rapidly. Conscientious monitoring of core temperature, urinary output, ECG, blood pressure, arterial blood gas levels, and serum electrolyte levels is required.
Malignant hyperthermia is a rare inherited muscle disorder that is chemically induced by anesthetic agents (Rothrock, 2003). At one time, mortality rates exceeded 80%. Since the introduction of dantrolene sodium in 1979, the development of genetics testing, and early detection and treatment with specific protocols, fatalities have been reduced to approximately 10% (McCarthy, 2004). However, identification of patients at risk for malignant hyperthermia is imperative. Susceptible people include those with strong and bulky muscles, a history of muscle cramps or muscle weakness and unexplained temperature elevation, and an unexplained death of a family member during surgery that was accompanied by a febrile response
During anesthesia, potent agents such as inhalation anesthetics (halothane, enflurane) and muscle relaxants (succinylcholine) may trigger the symptoms of malignant hyperthermia (Rothrock, 2003). Stress and some medications, such as sympathomimetics (epinephrine), theophylline, aminophylline, anticholinergics (atropine), and cardiac glycosides (digitalis), can induce or intensify such a reaction.
The pathophysiology is related to a hypermetabolic condition in skeletal muscle cells that involves altered mechanisms of calcium function at the cellular level. This disruption of calcium causes clinical symptoms of hypermetabolism, which in turn increases muscle contraction (rigidity) and causes hyperthermia and subsequent damage to the central nervous system.
The initial symptoms of malignant hyperthermia are related to cardiovascular and musculoskeletal activity. Tachycardia (heart rate greater than 150 bpm) is often the earliest sign. In addition to the tachycardia, sympathetic nervous stimulation leads to ventricular dysrhythmia, hypotension, decreased cardiac output, oliguria, and, later, cardiac arrest. With the abnormal transport of calcium, rigidity or tetanus-like movements occur, often in the jaw. The rise in temperature is actually a late sign that develops rapidly; body temperature can increase 1° to 2°C (2° to 4°F) every 5 minutes (Rothrock, 2003). The core body temperature can reach or exceed 42°C (104°F) in a very short time and must be properly monitored and recorded during surgery (McCarthy, 2004).
Recognizing symptoms early and discontinuing anesthesia promptly are imperative. Goals of treatment are to decrease metabolism, reverse metabolic and respiratory acidosis, correct dysrhythmias, decrease body temperature, provide oxygen and nutrition to tissues, and correct electrolyte imbalance. The Malignant Hyperthermia Association of the United States (MHAUS) publishes a treatment protocol that should be posted in the OR and be readily available on a malignant hyperthermia cart.
As soon as the diagnosis is made, anesthesia and surgery are halted and the patient is hyperventilated with 100% oxygen. Dantrolene sodium (Dantrium), a skeletal muscle relaxant, and sodium bicarbonate are administered immediately (McCarthy, 2004). Continued monitoring of all parameters is necessary to evaluate the patient's status. Although malignant hyperthermia usually manifests about 10 to 20 minutes after induction of anesthesia, it can also occur during the first 24 hours after surgery.
Although malignant hyperthermia is uncommon, the nurse must identify patients at risk, recognize the signs and symptoms, have the appropriate medication and equipment available, and be knowledgeable about the protocol to follow. This preparation may be lifesaving for the patient.
Disseminated Intravascular Coagulation
Disseminated intravascular coagulation (also referred to as coagulopathy [DIC]) is a life-threatening condition that is characterized by thrombus formation in the microcirculation and depletion of select coagulation proteins, causing hemorrhaging. The exact cause is unknown, but predisposing
P.518factors include many conditions that may occur with emergency surgery, such as massive trauma, head injury, massive transfusion, liver or kidney involvement, embolic events, and shock. The signs and symptoms, nursing assessment, and treatment of DIC are discussed in