The American Association of Nurse Anesthetists (AANA),⁶ the American Society of Anesthesiologists (ASA),^7,8 and The Joint Commission^9–13 have established written standards and professional commentary to provide for the basic rights and safety of patients, along with the safety of anesthesia providers and ancillary personnel. As technology advances, these standards are adapted and new recommendations are made.

Licensed registered nurses who are not qualified anesthesia providers have become involved in the monitoring of patients and the administration of medications for procedural sedations involving therapeutic and diagnostic procedures, as well as for certain surgical procedures.

The AANA and the ASA separately and together have issued statements in regard to criteria (Box 52-3) that must be met by non-anesthesia providers to protect the safety and well-being of the patient.^14,15

BOX 52-3 Criteria for the Management and Monitoring of Patients Undergoing Sedation Delivered for Therapeutic or Diagnostic Procedures by Non-Anesthesia Providers

• Guidelines for patient monitoring, drug administration, and protocols are available for dealing with potential complications or emergency situations, developed in accordance with accepted standards of anesthesia practice.

• A qualified anesthesia provider or attending physician selects and orders the agents to achieve sedation and analgesia.

• Registered nurses who are not qualified anesthesia providers should not administer agents classified as anesthetics, including but not limited to ketamine, propofol, etomidate, nitrous oxide, and muscle relaxants. (A computer-assisted personalized sedation device [CAPS] is being developed to enable a non-qualified anesthesia provider [physician-nurse team] to safely and effectively administer propofol for colonoscopy or esophagogastroduodenoscopy [EGD] procedures.)

• The registered nurse managing and monitoring the patient receiving an analgesia sedation shall have no other responsibilities during the procedure.

• Venous access shall be maintained for all patients having sedation and analgesia.

• Supplemental oxygen shall be available for any patient receiving sedation and analgesia and, when appropriate, in the postprocedure period.

• Documentation and monitoring of physiologic measurements including but not limited to blood pressure, respiratory rate, oxygen saturation, cardiac rate and rhythm, and level of consciousness should be recorded at least every 5 minutes.

• An emergency cart must be immediately accessible to every location where analgesia sedation is administered. This cart must include emergency resuscitative drugs, airway and ventilatory adjunct equipment, defibrillator, and a source for administration of 100% oxygen. A positive-pressure breathing device, oxygen, suction, and appropriate airways must be placed in each room where analgesia sedation is administered.

• Back-up personnel who are experts in airway management, emergency intubations, and advanced cardiopulmonary resuscitation must be available.

• A qualified professional capable of managing complications is present in the facility and remains in the facility until the patient is stable.

• A qualified professional authorized under institutional guidelines to discharge the patient remains in the facility to discharge the patient in accordance with established criteria of the facility.

Standards for the Delivery of Anesthesia in a Remote Location

A Perform a complete preanesthesia assessment.

The patient, parent(s), or legal guardian(s) must be thoroughly and unhurriedly interviewed before the performance of an anesthetic procedure. The preanesthesia assessment should be performed in consideration of the patient’s right to privacy and confidentiality and which safeguards their dignity and respects aspects of their psychological, cultural, and spiritual values. During this assessment, information is obtained regarding the patient’s medical history (prior allergy must be assessed), anesthesia history (noting any prior complications and responses to prior anesthetic experiences), surgical history, and medication history (including tobacco, alcohol, and any substance abuse). A complete physical assessment of the patient is made, along with inspection of the head, neck, mouth, and airway. The anesthetist’s head and neck assessment can be especially beneficial to the patient’s well-being, because common oral conditions and suspicious head/neck, skin, and oral pathologic lesions can be detected and referred for further evaluation by a dentist or a physician. Early referral for diagnosis and treatment of any disease contributes to patient cure and recovery to wellness, as well as reduced morbidity and mortality.¹⁶ Lung and heart sounds are auscultated. Review is made of objective diagnostic data such as patient laboratory values, radiographs, and electrocardiogram (ECG). Important findings are noted in the patient’s anesthesia record. A physical status classification is then assigned the patient.

Box 52-4 outlines specific patient conditions that alert the anesthetist to a need for special attention and care for anesthetics provided for therapeutic and diagnostic procedures.

BOX 52-4 Specific Patient Conditions That Warrant Anesthesia-Care Vigilance

• Mental impairment with no possibility of cooperation

• Severe gastroesophageal reflux; delayed gastric emptying; aspiration risk

• Gastroparesis secondary to diabetes mellitus

• Orthopnea; obstructive sleep apnea

• Decreased level of consciousness; depression of airway protection reflexes

• Increased intracranial pressure

• Known difficult intubation; assessed oral, dental, craniofacial, cervical, or thoracic abnormalities that could preclude airway access and maintenance

• Respiratory tract infection; unexplained fever

• Morbid obesity

• Therapeutic or diagnostic procedures that impede access to the airway

• Therapeutic or diagnostic procedures that are complex, lengthy, painful, or invasive

• Positioning that is complex, atypical, painful; prone position

• Patient suffering acute trauma

• Patients at extremes of age

• Prematurity

• Physical status 3 or 4

B Obtain informed consent for the planned anesthetic intervention from the patient or legal guardian.

The anesthesia provider should discuss the course of the anesthetic care and enumerate the following in understandable terms appropriate for the patient or guardian:

• How the anesthetic procedure will be performed

• Possible risks of the anesthetic procedure

• Pertinent possible reactions or complications the patient might expect while receiving a typical anesthetic, along with informing the patient or guardian that the anesthetist has permission to make changes or adjustments as deemed necessary in his or her professional judgment

• Possible options to the type of anesthetic to be received by the patient

• The ability for the patient/parent(s)/guardian(s) to have any concerns addressed and questions answered

At times, anesthesia for therapeutic and diagnostic procedures will require only minimal, moderate, or deep sedation, which by definition may not include patient amnesia. Only general anesthesia ensures amnesia as a standard of care. Therefore, discussion of what the patient can reasonably expect should take place at this time.17,18 It is far easier to discuss these points with the patient before the anesthetic procedure than to explain these points after the fact.

C Formulate a patient-specific plan for anesthesia care.

The art and science of anesthesia mandate that the safest and least invasive anesthetic technique be administered to the patient to simplify delivery of the anesthetic and to avoid complications for the patient while in the remote location.

D Implement and adjust the anesthesia care plan based on the patient’s physiologic response.

Immediately before implementation of anesthesia, reassess the patient (e.g., vital signs, airway status, and response to preprocedure medications given), and document a reassessment note in the anesthesia record. The Joint Commission defines “immediately” as the moments just before the sedation is administered. Also, make sure all anesthesia equipment, supplies, and medications are checked and immediately available in case the patient needs a change in the anesthetic plan.

E Properly prepare, dispense, and label all medications to be used for the patient.

All medications drawn up prior to the case must be labeled with the drug name, strength (concentration), amount (if not apparent from the container), and expiration date (if not used within 24 hours). Medications drawn up and used immediately for the procedure do not require labeling.

F Adhere to appropriate safety precautions, as established with the institution, to minimize the risks of fire, explosion, electrical shock, and equipment malfunction.

This standard is important for the patient, the anesthesia provider, and ancillary personnel for the prevention of accidents and injury. It is also important from a medicolegal standpoint. The anesthesia provider should also be an integral part of the team involved with protocols for preventing wrong site, wrong procedure, and wrong person surgery, also known as the Universal Protocol established by The Joint Commission.19–23 Safety must be a consideration for scheduling obligations of anesthesia personnel because anesthesia for therapeutic and diagnostic procedures is often more involved and complex when compared with anesthesia delivered in the operating room.

G Monitor and document the patient’s physiologic condition as appropriate for the type of anesthesia and specific patient needs.6,7

• Monitor ventilation continuously. Ventilation may be monitored in the patient undergoing mild, moderate, or deep sedation with a precordial stethoscope or by direct auscultation of the patient’s ventilatory effort. Verify intubation of the trachea by auscultation, chest excursion, and confirmation of carbon dioxide in the expired gas. In cases of moderate or deep sedation, the ASA has set forth new guidelines mandating the measurement of end-tidal carbon dioxide unless the patient, procedure, or equipment interfere or preclude monitoring. Continuously monitor end-tidal carbon dioxide (ETco₂) during controlled, assisted, or spontaneous ventilation, including any anesthesia or sedation technique requiring artificial airway support. Use spirometry and ventilatory pressure monitors as indicated.¹³

• Monitor oxygenation continuously by clinical observation, pulse oximetry, cerebral oximetry, and, if indicated, arterial blood gas analysis.

• Monitor cardiovascular status continuously via electrocardiography and heart sounds. Record blood pressure and heart rate at least every 5 minutes.

• Consider the use of a monitor of anesthesia awareness/level of consciousness/depth of sedation via electroencephalographic processing for procedures intended to produce loss of consciousness.²⁴ It is recommended that consciousness monitoring be used when available; however, the research remains inconclusive regarding the effectiveness of this evolving technology.^25,26

• Monitor body temperature continuously in all patients when clinically significant changes in body temperature are intended, anticipated, or suspected. Maintenance of normothermia must be an integral part of the anesthetic plan to preserve essential body functions (Box 52-5) and to prevent complications leading to patient morbidity and mortality.^27,28 Temperature monitoring is a standard of care when delivering general anesthesia to the patient and optional while performing mild, moderate, or deep sedation.

BOX 52-5 Reasons for Maintaining Normothermia for Therapeutic and Diagnostic Procedures

• To decrease sympathetic activity related to vasoconstriction while hypothermic

• To decrease cardiac morbidity and cardiac demand during recovery from hypothermia

• To minimize patient morbidity and discomfort related to being cold and shivering

• To maintain the normal pharmacokinetics of administered medications (Hypothermia decreases the normal metabolism of medications.)

• To decrease anesthesia recovery time (Hypothermia impairs the rapid recovery from anesthesia.)

• To maintain bodily metabolic functions (The enzymes involved in body metabolic chemical reactions function ideally at normothermia.)

• To maintain normal blood coagulation and to decrease blood loss. (The coagulation cascade is impaired or delayed during hypothermia.)

• To decrease the incidence of wound infection

• To decrease the incidence of complications that may require hospitalization

• Monitor neuromuscular function and status prior to the procedure and recovery when neuromuscular blocking agents are administered.

• Monitor and assess patient positioning and protective measures at frequent intervals. Periodic assessment of eye protection, skin, bony prominences, and extremities is necessary.

• Perform a complete anesthesia equipment safety check daily and document in the patient’s medical record. An abbreviated check of all equipment is acceptable before each subsequent anesthetic is administered.

Patient indications for the necessity of anesthesia in remote locations are listed in Box 52-6.

BOX 52-6 Patient Indications for the Necessity of Anesthesia in Remote Locations

Central Nervous System

• Presenile dementia

• Drug-induced mental disorders

• Major depressive disorders or schizophrenia

• Hysteria, unspecified (includes fear of pain)

• Phobic disorders, unspecified (claustrophobia)

• Transient cerebral ischemia

• Cerebrovascular disease, other and ill-defined

Cardiovascular

• Hypertensive heart disease, malignant, benign, unspecified

• Ischemic heart disease, acute or subacute forms

• Old myocardial infarction

• Coronary atherosclerosis, bundle branch block, other and unspecified cardiac dysrhythmias

• History of atrial or ventricular fibrillation or flutter

Pulmonary

• Bronchitis, acute, chronic, or unspecified

• Chronic airway obstruction

• Radiation-induced pulmonary disease, acute or chronic

Other

• Acquired hypothyroidism

• Electrolyte imbalance

• Morbid obesity

• Adverse effects not classified elsewhere

• Opioid, barbiturate, cocaine, cannabis, amphetamine, or unspecified drug dependence

• Combative patient

• Patient with low pain thresholds or experiencing severe pain

• Chronic liver disease or cirrhosis

• Gastrointestinal (GI) tract hemorrhage, unspecified

Pediatric

• Procedure is lengthy or painful

• The child is uncooperative or seems uncomfortable

• The operative or diagnostic area of interest lies close to critical anatomic structures

• The child is completely covered, which impedes quick access to the airway

• If an air embolus may be avoided by using an endotracheal tube or laryngeal mask airway

Modified from Bader AM, Pothier MM. Out-of-operating room procedures: preprocedure assessment. Anesthesiol Clin. 2009;27(1):121-126; Cutter TW. Radiologists and anesthesiologists. Anesthesiol Clin. 2009;27(1):95-106.

H Precautions shall be taken to minimize the risk of infection to the patient, the operator, and ancillary personnel.

Clean equipment and fresh medications and supplies (to include personal protective equipment and supplies) should be used to ensure safety.

I There shall be complete, accurate, and time-oriented documentation of pertinent information on the patient’s anesthesia record.

Document baseline patient vital signs before the anesthetic procedure and the therapeutic or diagnostic procedure has begun. Documentation must be made of all vital signs: heart rate, blood pressure, pulse oximeter readings, patient temperature, and the presence of ETco₂. Also, documentation that includes names and quantities must be made of all fluids and drugs administered. A narrative must be written concerning the technique(s) of anesthesia used and any unusual events that occurred during the anesthetic period. An anesthesia form approved by the AANA is available on their website.

J After the anesthetic treatment for therapeutic or diagnostic procedures, transfer the responsibility for care of the patient to other qualified personnel in a manner that ensures continuity of care and patient safety.

Anesthesia care does not end with the completion of the therapeutic or diagnostic procedure. The patient may receive postanesthesia care at the site of the therapeutic or diagnostic procedure. Those sites that preclude postanesthesia recovery at that particular location must be safely transported to a separate area for postanesthesia care. From there patient care can be transferred to another qualified healthcare provider along with a full verbal report. To whom the report was given must be documented as well. The transported patient must be accompanied by a person capable of initiating basic life support (CPR), and that person must have immediate access to portable anesthesia monitors, equipment, and supplies, especially if transport will require some time and/or distance. Recovery from anesthesia can be divided into three phases. Phase I recovery encompasses the recovery from sedation, during which assessment is made of adequate patient oxygenation and respirations, cardiovascular function, neuromuscular function, mental status, body temperature, pain, postoperative nausea and vomiting (PONV), fluid status, urine output, the ability to void, and any bleeding or drainage, which must be noted and continually assessed. Treatments may be administered as necessary for any adverse signs or symptoms elicited by the patient. Phase II recovery encompasses the adequate resumption of psychomotor functions, such as the ability to communicate, ambulate, and consume fluids. Finally, before discharge from this area, a responsible individual must be present to escort the patient home and be available to observe and assist the patient for the next 24 hours. In phase III recovery, the patient regains full preanesthetic psychological and physical recovery.²⁹ It is important to remember that phase III may occur several hours or days later, depending on the anesthetic technique and patient variables, but with newer anesthetics, recovery time has dramatically decreased. Postanesthesia recovery and discharge guidelines are discussed in Chapter 50.

K Reimbursement.

Third-party payers of anesthesia services may require documentation of the necessity for anesthetic services for therapeutic and diagnostic procedures. Box 52-6 lists some patient indications that can require the need for anesthesia in remote locations.

L Conclusion.

The standards listed in this section describe the minimum requirements for treatment and monitoring of any patient who requires anesthesia care. The standards must be followed wherever and whenever anesthesia is given. Adherence to standards is considered essential in a malpractice case, and an anesthetic incident will be judged according to those standards.³⁰ The omission of any monitoring standard should be documented and the reason for such omission stated on the patient’s anesthesia record. Any anesthetic procedure, including those performed in a remote location, should not begin until the anesthetist feels sufficiently comfortable, safe, and well prepared to deliver the anesthetic treatment required for the patient.

Guidelines for Sedation

Therapeutic and diagnostic procedures can be performed with various types of sedation. Sedation is possible with enteral, parenteral (intravenous), and inhaled medications. It is important to remember that the depth of sedation in a patient is a continuum of progressive changes in cognition, respirations, and protective reflexes.³¹ Sedation does not have strict boundaries. The patient may quickly progress from one level of sedation/anesthesia to another; therefore, it is essential that the competent anesthesia provider is able to rescue patients in each level, as well as have quick access to vital equipment, supplies, and trained and qualified ancillary personnel who are familiar with anesthesia delivery, emergencies, and monitoring.^3,31–33

Box 52-7 lists ancillary personnel requirements the anesthetist should consider during the planning stages of anesthesia for therapeutic and diagnostic procedures.

BOX 52-7 Considerations and Requirements of Ancillary Personnel for Areas of Anesthesia Delivery for Therapeutic or Diagnostic Procedures in Remote Locations

• Training in basic life support

• Awareness of and training in emergency protocols

• Familiarity with anesthesia responsibilities; to serve as an assistant

• Assist with patient positioning and comfort

• Training in postprocedure observation and recovery

Modified from Robbertze R, et al. Closed claims review of anesthesia for procedures outside the operating room. Curr Opin Anaesthesiol. 2006;19:436-442; Metzner J, et al. The risk and safety of anesthesia at remote locations: the US closed claims analysis. Curr Opin Anaesthesiol. 2009;22(4):502-508; Frankel A. Patient safety: anesthesia in remote locations. Anesthesiol Clin. 2009;27(1):127-139.

The Joint Commission and the ASA publish definitions for the four levels of sedation and anesthesia in their Comprehensive Accreditation Manual for Hospitals: The Official Handbook (CAMH).³¹ Box 52-8 lists definitions of the four levels of sedation and anesthesia as described by The Joint Commission and the ASA. Figure 52-1 illustrates the continuum of sedation described by the two aforementioned groups. From these definitions, standards are provided to practitioners for the administration of safe and high-quality care to patients.³²

BOX 52-8 The Continuum of Depth of Sedation: The Four Levels of Sedation and Anesthesia

Minimal Sedation (Formerly Known as Anxiolysis)

A drug-induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected.

Moderate Sedation/Analgesia (Formerly Known as Conscious Sedation)

A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. (note: Reflexive withdrawal from a painful stimulus is not considered a purposeful response.)

Deep Sedation/Analgesia

A drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully after repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.

Anesthesia (General Anesthesia)

Consists of general anesthesia and spinal or major regional anesthesia. It does not include local anesthesia. General anesthesia is a drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive-pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired.

Modified from The Joint Commission. Comprehensive Accreditation Manual for Hospitals: The Official Handbook (CAMH) (refreshed core). Chicago: The Joint Commission; 2009; American Society of Anesthesiologists: Continuum of Depth of Sedation: Definition of General Anesthesia, and Levels of Sedation/Analgesia. Accessed September 19, 2012, at the ASA website http://www.asahq.org/for-members/standards-guidelines-and-statements.aspx

FIGURE 52-1 Depth of sedation continuum.

Accepted standards for moderate sedation/analgesia and deep sedation/analgesia state the following 11,31,32,34:

1. The process from minimal sedation (anxiolysis) to general anesthesia is a continuum, and individuals vary in their responses to medications.

2. Qualified individuals with appropriate credentials (e.g., nurses, certified registered nurse anesthetists [CRNAs], anesthesiologists, dentists) who are trained in professional standards and techniques do the following:

a. May administer pharmacologic agents to achieve a desired level of sedation.

b. Must monitor patients carefully to maintain the patient’s vital functions at the desired level of sedation. Appropriate equipment must be available for monitoring heart rate via ECG, respiratory rate and adequacy of pulmonary ventilation, oxygenation via pulse oximetry, and blood pressure measurement at regular intervals (at least every 5 minutes).

c. Must be competent to evaluate the patient before performing the moderate sedation/analgesia and deep sedation/analgesia.

d. Must be competent to support the patient’s psychological functions and physical comfort.

e. Must be competent in the administration of sedatives, analgesics, hypnotics, and other medications to produce and maintain moderate sedation/analgesia and deep sedation/analgesia.

f. Must be competent to rescue the patient who unavoidably or unintentionally moves into a deeper than desired level of sedation and analgesia. In the case of the CRNA, competency is mandatory for all levels of the sedation continuum. This includes competency in management of a compromised airway, the provision of oxygen, and the initiation of emergency rescue procedures such as basic life support (BLS), advanced cardiac life support (ACLS), or pediatric advanced life support (PALS). In addition, for patients undergoing deep sedation/analgesia, one must also have competency to manage an unstable cardiovascular system.

g. Must be competent to assess and treat problems the patient may attain related to the therapeutic or diagnostic procedure he or she is having performed.

h. Must properly document the patient’s response to care.

i. Must supervise recovery of the patient after the sedation in a postsedation area or a postanesthesia recovery area.

j. Must discharge the patient. This may be done in consultation with qualified personnel and/or the physician, surgeon, or dentist.

3. Adequate numbers of qualified and competent personnel must be present during the performance of moderate sedation/analgesia, deep sedation/analgesia, and general anesthesia to serve as a skilled second pair of hands if necessary. This should include not only qualified anesthesia providers as described earlier but also nurses, assistants, technicians, and other office staff to meet the needs of the patient.³¹

The Pediatric Patient

The pediatric population can pose complex challenges for the delivery of anesthesia (Box 52-9). Pediatric patient behavior and degree of cooperation can range from very helpful to extremely anxious. Fortunately, several common anesthetic medications can help patients with slight to high levels of anxiety. Pediatric sedation and anesthesia increases the quality of care the patient receives by greatly reducing anxiety and by eliminating movement when necessary for therapeutic or diagnostic procedures.

BOX 52-9 Goals of Pediatric Anesthesia

• Foremost, to provide safety and welfare to the patient

• To minimize physical discomfort/pain or to provide more profound analgesia when necessary to the patient

• To minimize negative psychological consequences of the therapeutic or diagnostic procedure for both the pediatric patient and the parent(s)/guardian(s). This can be accomplished by the provision of proper preprocedure discussions along with sedative medications, analgesics, and amnestic agents for the patient

• To ideally obtain patient cooperation and safely control uncooperative or endangering behavior

• To obtain immobility of the patient to achieve therapeutic or diagnostic procedure goals

• To provide the patient a safe discharge to the guardian and to home

• To minimize or eliminate patient complications from applied therapeutic or diagnostic procedures and administered anesthetic medications

Modified from Cravero JP, et al. The incidence and nature of adverse events during pediatric sedation/anesthesia with propofol for procedures outside the operating room: a report from the Pediatric Sedation Research Consortium. Anesth Analg. 2009;108:795-804.

First and foremost in the practice of nurse anesthesia are patient safety and guardianship of patient welfare. Important lessons can be learned from the literature regarding anesthesia in pediatric patients. Children under the age of 5 years seem to be at the greatest risk for adverse events, even with no underlying disease. Adverse events have occurred more commonly with the use of multiple drugs, especially sedative medications.35–39 The problems encountered most often are respiratory events: respiratory depression, respiratory obstruction, and apnea.^36–38

Adverse events can be reduced by proper adherence to patient selection and a comprehensive preoperative assessment, proper dosage of medications to minimize unexpected responses, proper monitoring, skilled administration of anesthesia, and proper recovery time. The anesthesia provider must plan to minimize the possibility of adverse reactions.36–39 General patient selection criteria to help minimize the possibility of adverse events are seen with patients 6 months of age and older and applied during the preoperative assessment. It is during this time that the temperament of the child can be assessed.⁴⁰ Consideration must be made for the type of procedure to be performed, past medical history, past sedation/anesthesia history, current medication therapy, allergies, and respiratory or airway difficulties.^35,37,40 Questions regarding the degree of patient stimulation expected throughout the procedure, amount of anticipated blood loss, ability to maintain normothermia, and ability to have close proximity in which to monitor the patient, are all questions the anesthesia provider is responsible for addressing. It is found that adverse reactions are reduced with procedures that last less than 1 hour.³⁹ Clear communication with the technician and the medical practitioner is essential to clarify the requirements for the patient to be safe and properly anesthetized for the procedure.

The pediatric patient and the parent or legal guardian must be properly prepared for the planned therapeutic or diagnostic procedure. Clear explanation of the entire anesthetic process to the parent or guardian is based on the developed treatment plan and is offered in age-appropriate terms for the pediatric patient.35,40 “Inform before you perform.”

Fasting times are constantly being reevaluated in clinical anesthesia and must be stringently adhered to. Fasting guidelines are discussed in Chapters 19 and 48. Premedication with oral, intranasal, intramuscular, or rectal sedatives may be necessary. Common pediatric premedications and doses are chosen as appropriate.^40–44

It is essential to have qualified personnel to assist in the safe care of pediatric patients receiving anesthesia in remote locations for therapeutic or diagnostic procedures. An extra pair of trained hands enhances the ability for the patient to receive safer care throughout the entire procedure.

Knowledge of the most common causes of adverse pediatric anesthesia events can help the anesthetist plan for and avoid these events (Box 52-10).^36,37,39 Most anesthesia adverse events are caused when multiple anesthetic agents are used. Adverse events are not dependent on the class of the drug (e.g., opioids, benzodiazepines, barbiturates, antihistamines, local anesthesia, intravenous anesthesia, inhaled anesthesia) or the route of administration (e.g., oral, rectal, nasal, intramuscular, intravenous, local infiltration, inhalation).37,38,45,46

BOX 52-10 Most Common Causes of Pediatric Anesthesia Adverse Events for Therapeutic or Diagnostic Procedures

• Drug errors

• Nitrous oxide in combination with any other sedative medication

• Inability to rescue the patient from an adverse anesthetic event

• Unmet monitoring standards—especially respiration, oxygenation

• Respiratory depression/hypoventilation/apnea

• Airway obstruction

• Bradycardia secondary to hypoxia

• Laryngospasm/stridor

• Vomiting, aspiration, diarrhea

• Hypotension

• Inadequate sedation/paradoxical excitation (sustained irritability or combativeness)

• Prolonged sedation after the procedure

The Geriatric Patient

As a result of a number of factors, including better nutrition, more physical activity, less tobacco and alcohol use, and improved medical care and medical technologies, more Americans are living longer. In 2008 the U.S. Census Bureau released population projections stating that the population of people within the United States currently over the age of 65 is 14.8% and will reach 20% by 2025 and 24.6% by 2050, with continued increased life expectancy.⁴⁷ The increasing elderly population is placing, and will continue to place, many demands on the public healthcare system. Medical technology is advancing, and therefore more procedures requiring anesthesia will be performed in elderly patients. It is estimated that 20% to 40% of anesthesia cases may be performed outside of the traditional operating room and that the elderly prefer ambulatory settings, with trends pointing toward more invasive therapeutic or diagnostic procedures.⁴⁸ Perioperative complications can increase with age. Special considerations related to the physiology of aging are necessary if anesthetic treatment is to be performed safely.^48,49

The elderly have a greater prevalence of comorbidities such as atherosclerosis, infections, autoimmune diseases, chronic disorders, and cancer. The immune system gradually and slowly diminishes in function with age. Therefore, the ability to heal and fight foreign bacteria, viruses, and malignant cells diminishes. There are no fewer T cells in a person at an older age than at a younger age, but T-cell function is decreased in the elderly. Many of the body’s cells begin to diminish in function or to function abnormally. Cells also may have increasing difficulty in membrane transfer of nutrients and waste.⁴⁹

The normal aging process results in an increase in the ratio of adipose tissue to aqueous body tissues.49–50 This means more lipid-soluble anesthetic drug is stored. Basal metabolic rate and liver and kidney function all decrease with age. This results in a decrease in the rate of metabolism and excretion of anesthetic drugs. Nervous system function generally produces decreases in the perception of sight, hearing, touch, smell, taste, pain, and temperature sensations. Cerebral atrophy occurs with aging, resulting in an overall loss of neurons in the neocortex.⁵⁰ This suggests increased sensitivity to anesthetic medications. The elderly are at an increased risk for perioperative delirium and postoperative cognitive dysfunction.⁴⁸ Therefore, the dosage requirements for anesthetic drugs usually are decreased. The geriatric patient’s level of activity is one indicator of cardiovascular function and this generally decreases with age; this decrease in activity usually correlates with limited physiologic reserves. Patients may be restricted in their activity because of arthritis or other debilitation. Circulation time is decreased. Skeletal muscle size is decreased with decreases in physical activity, which decreases total oxygen consumption and blood-flow needs to the muscles, resulting in decreased cardiac output.⁵⁰ The ability of the cardiovascular system to respond to the effects of anesthetic drugs, fluid administration, and the stresses of therapeutic and diagnostic procedures can cause decreased cardiac function, resulting in hemodynamic instability and reduced circulation to vital organs.^48–50 Tissue oxygenation can decrease because of changes in ventilation ability and lung tissue. Lung compliance is decreased, resulting in ventilation-perfusion mismatch. Aging itself brings on the increasing inability to respond to hypoxia and hypercapnia, especially while experiencing the effects of anesthesia. Therefore, the anesthetist must always ensure and constantly monitor the supply of adequate amounts of oxygen to the elderly patient and be ready to offer needed respiratory support. The ability to thermoregulate is also decreased with age.⁴⁸ Body metabolism, enzyme function, and the coagulation cascade best function at 37° C. Changes in mental status or even delirium can occur more frequently in geriatric patients. All of these factors must be taken into consideration when one provides anesthesia to all patients, but especially to geriatric patients.

Significant variability exists in each of these vital functions among patients. Geriatric patients who are more physically fit have a decreased mortality, reduced incidence of cardiovascular disease, lower blood pressure, reduced blood cholesterol, and most important, better bodily reserves when they become surgically challenged or sick.⁴⁹ A thorough and comprehensive preanesthetic assessment is necessary, from which a plan of treatment can be deduced.⁴⁸

To prevent confusion, delirium, or cognitive impairment in the elderly, agents with short half-lives and durations are ideal.51,52 Carefully consider the use of drugs that are synergistic or antagonistic in their effects. Such drugs as propofol, midazolam, fentanyl, alfentanil, remifentanil, and local anesthetics are ideal because doses are calculated and titrated according to the patient’s responses. Most literature reports no difference of outcome in the elderly as a result of anesthetic choice when either a regional anesthetic or general anesthesia is used.⁴⁸

Several electroencephalographic (EEG) processing monitors are available that help in assessment of patient responses to anesthetic medications. These devices monitor anesthesia awareness/level of consciousness/depth of sedation, and response to anesthetic medications, which allows for more precise titration of anesthetic medications according to the patient’s needs. Care must be taken to preserve body warmth and ensure the continual delivery of adequate warmth when necessary. Ensure the protection of the eyes, skin, and the extremities while moving the patient and during the procedure by skin padding of bony prominences.⁴⁰ Consideration must also be given to the preprocedure, and postoperative care of the elderly patient in regard to possible malnutrition, depression, immobility, cognitive dysfunction, pulmonary difficulty, dehydration, acute pain, and chronic pain.⁴⁸ Finally, consider verbal and written postoperative instructions to both the elderly patient and caregivers/significant others who will accompany the patient and be present to both monitor and care for the elderly patient after a therapeutic or diagnostic procedure.⁵¹

A new formulations of propofol is available for use in anesthesia for therapeutic and diagnostic procedures (see Chapter 9 for a complete discussion). Fospropofol (Lusedra) is a water-soluble prodrug that is enzymatically converted to propofol. The formulation contains no lipids, egg, or preservative products and therefore has a decreased likelihood of allergic reactions or bacterial growth. Pain on injection is also decreased since it is not a lipid formulation. Because of its need to be converted to propofol, Fospropofol has a delayed onset and slightly prolonged duration when compared with propofol.⁵² Some studies suggest that it is an ideal sedative choice for the geriatric patient with multiple comorbidities due partly to its lower rate of apnea and respiratory depression.^52–54

It is estimated that between 170,000 and 462,000 people within the United States experience sudden cardiac death each year, and of those, 50% to 70% do not survive the event.⁵⁵ Patients who experience sudden cardiac death are usually around 60 years of age, and their most common underlying rhythm is pulseless ventricular tachycardia (VT) or ventricular fibrillation (VF).^55,56

Defibrillation is the application of a flow of electric current through the appropriate chambers of the heart to completely depolarize the entire myocardium to restore a suitable heart rhythm to sustain life.57–59 If enough stores of high-energy adenosine triphosphate molecules remain and are available within the myocardium, automaticity can resume. Fibrillating myocardium rapidly consumes high-energy phosphate molecules.^50,59 It has been proven that early defibrillation, along with cardiopulmonary resuscitation, can result in high long-term survival rates. The automatic implantable cardiac defibrillator (AICD) is designed to bypass the delay patients experienced before receiving defibrillation. The AICD is composed of two basic parts: a pulse generator and a lead electrode for detection of dysrhythmias, delivery of a defibrillating shock, cardiac pacing, telemetry, and provision of diagnostic data. The pulse generator is a hermetically sealed titanium can that contains a computer microprocessor, resistors, transformers, capacitors, and a battery. The battery is designed to deliver 120 shocks and usually lasts for 3 to 6 years. The computer is programmed with algorithms to detect VT and VF. If VF occurs, an electric shock is administered within 10 to 15 seconds of detection (much of the time delay results from the charging of the capacitor). VT is treated with overdrive pacing called antitachycardia pacing (ATP). ATP is an extremely successful procedure. AICD implantation has been a crucial technique for prevention of sudden cardiac death.⁶⁰

A cardiac pacemaker is used to treat bradycardia, atrioventricular block, sinus nodal dysfunction, and other dysrhythmias. The pacemaker is used concurrently with other therapies for management of dysrhythmia and hemodynamics. The pacemaker consists of a pulse generator containing a computer and a battery that is designed to last 6 to 10 years. Attached to the pulse generator is a lead, which delivers the current used to depolarize the myocardium, and an anode, which completes the electrical circuit. Two different types of pacemaker leads are available. A unipolar pacemaker lead uses one lead as the cathode and the pulse generator as the anode. Unipolar leads are less likely to fail. A bipolar pacemaker uses two separate leads that are close together, the advantage of which is a sharper signal with less noise. The leads are inserted under fluoroscopic guidance via the cephalic vein or the subclavian vein into the cardiac chamber, usually the right ventricle in the case of an AICD and the right atrium and right ventricle for a cardiac pacemaker. The leads are then tunneled and connected to the pulse generator, which is then inserted into a subcutaneous pocket in the patient’s pectoral region or into a subpectoral muscle pocket.⁶⁰ Figure 52-2 shows a postoperative radiograph of a pacemaker pulse generator, computer, and battery inserted into a patient. Figure 52-3 shows a postoperative radiograph of a unipolar pacemaker lead inserted into the right ventricle of a patient. Research and continual improvements allow more people to receive better and more reliable AICD and cardiac pacemaker therapy.

FIGURE 52-2 Radiograph of a pacemaker pulse generator, computer, and battery inserted into a patient.

FIGURE 52-3 Radiograph of a unipolar pacemaker lead inserted into the right ventricle of a patient.

Anesthetic Considerations

The AICD or cardiac pacemaker procedure may be performed in the operating room, in a special cardiac procedure room, or in the cardiac catheterization suite by a cardiologist or other physician.⁶¹ Routine monitors are attached to the patient, with special attention paid to a properly functioning five-lead ECG. The ECG monitor screen must be available to the anesthesia team, the operating physician, and the AICD or pacemaker manufacturer’s technical service representative, who is always present during insertion. The procedures are usually adequately performed with local anesthetic and moderate sedation/analgesia or deep sedation/analgesia, although some clinicians prefer a general anesthetic.

AICD insertion requires purposeful triggering of VF in an attempt to test thresholds and functioning of the AICD.⁶² A range of anesthesia techniques from mild sedation with local anesthesia infiltrate to general anesthesia may be required depending upon factors such as surgeon preference, procedural length, number of thresholds tests, and patient physical and mental status. As in all anesthetic procedures, endotracheal intubation may be required to secure the airway in case a cardiac emergency arises.

After insertion of the cardiac pacemaker and before wound closure, the device is threshold tested by the pacemaker manufacturer’s technical service representative to ensure adequate contact between the leads and the myocardium.60,61 After wound closure and dressing application, all computer-function programming of either the AICD or the cardiac pacemaker can then be performed with a pacemaker programmer that connects to a portable wand. The wand is placed within close proximity to the implanted pulse generator by the manufacturer’s technical service representative, which allows a telemetric connection to properly program or interrogate the AICD or cardiac pacemaker.

Postanesthesia Care

When the procedure is completed, the patient is transported to the recovery room with oxygen and observed for any hemodynamic or cardiovascular ECG changes.

AICDs are generally well tolerated by patients. Some patients display anxiety or depression because of the possibility of sudden cardiac death, device failure, inappropriate shocks, and recalls of certain devices.⁶¹ Shocks from the AICD are described as a sudden, heavy blow to the chest. Medical technology is ever improving, and the demand for AICDs and cardiac pacemakers increases annually.

Cardioversion

Procedure Overview

Cardioversion is the discharge of electrical energy, synchronized to the R wave of the QRS complex of the electrocardiogram, to convert hemodynamically unstable supraventricular rhythms such as atrial flutter or atrial fibrillation or hemodynamically stable VT. These rhythms can be life threatening if left untreated. Atrial flutter and atrial fibrillation are associated with the development of congestive heart failure and with the formation of thromboemboli, which can lead to stroke. Cardioversion is usually a scheduled and planned procedure unless the patient’s condition warrants otherwise. Patient optimization may not be possible if there is urgency for cardioversion as a result of hemodynamic instability. Much less electrical energy is required to synchronously cardiovert a patient when compared with asynchronous defibrillation.⁵⁸ Defibrillation is an unplanned and usually emergent application of unsynchronized electrical energy. Cardioversion is believed to be therapeutic because it closes an excitable gap in the myocardium, which causes currents to reenter and excite the electrical system of the heart.⁶¹

Anesthetic Considerations

Because cardioversion is usually a nonemergent and planned procedure, patient conditions usually can be optimized. Proper nothing-by-mouth (nil per os [NPO]) status must be observed unless the cardioversion is deemed urgent or emergent. Standard monitors are applied, with special attention paid to the ECG. A monitor of anesthesia awareness/level of consciousness/depth of sedation via electroencephalographic processing can be used to assess consciousness during cardioversion.63–64 Intravenous access is necessary. The energy required for cardioversion is measured in joules (watt-seconds). The cardiologist or physician uses a cardioverter-manual monophasic or biphasic defibrillator for the procedure. The optimal shock dose for cardioversion of atrial flutter and other supraventricular tachycardias is 50 to 100 J.^57–59,65 The operator applies cardioversion-defibrillator paddles with conduction gel or defibrillator pads to the patient’s skin. One paddle or pad is placed parasternally over the second and third intercostal space. The other paddle or patch is placed over the area of the apex of the heart.^56–59 The cardioverter-defibrillator is set to the synchronized (sync) mode. Visible synchronization marks are placed by the cardioverter atop the tallest R waves of the ECG. Energy shocks are delivered initially at 50 to 100 J and are titrated progressively, up to 360 J as necessary, after observation of the effectiveness of the synchronized shock.^58–59,65

Midazolam may be administered as both a sedative and amnestic agent before cardioversion. The patient is then assisted in breathing oxygen via facemask and Ambu bag with high-flow oxygen. Because of the intense and brief pain of cardioversion, an ultra–short-acting general anesthetic such as propofol or etomidate is administered.63–64 After the loss of eyelash reflex occurs, an “all-clear” signal is given by the operator. Positive-pressure respirations are temporarily suspended, with care taken not to touch any part of the patient or the patient’s bed. Then the synchronized shock or shocks are administered.^64,65 Muscle relaxation is not necessary. As always, an assortment of oral airways, nasal airways, laryngeal mask airways (LMAs), endotracheal tubes, and laryngoscopes with blades and suction should be readily available in case complications occur. If cardioversion is required in a patient who has not fasted, general anesthesia with tracheal intubation is necessary to prevent aspiration of gastric contents.⁶⁴