Sedation and Monitoring in Endoscopy

Introduction

Sedation is regularly used to facilitate the performance of endoscopic procedures. Sedation practices have noticeably changed over the past decade, with a shift from no or moderate sedation to monitored anesthesia care (MAC) for gastrointestinal (GI) endoscopy.

Sedation during an endoscopic procedure helps in two ways; first, by decreasing procedural pain, thereby making the patient more comfortable, and second, by decreasing any untimely patient movements, thereby reducing complications. Both these factors affect the overall quality and safety of endoscopic procedures.

Sedation is associated with its own potential problems. Sedation-related complications, such as aspiration, oversedation, hypoventilation, and airway obstruction, make up more than half of all reported endoscopic complications.

Sedation use requires additional monitoring and recovery, and therefore has implications in the form of time, cost, and staffing. Due to these issues, some prior studies have advocated for the use of unsedated endoscopy ; however, the rate of use of unsedated endoscopy remains very low in the United States. The main reason for that is unpredictable patient tolerability during the endoscopic procedures. Several studies have shown that even though patients agree to undergo the procedure without sedation initially, the need for sedation later in the procedure causes significant delays in procedure completion when compared to patients who are sedated throughout the procedure.

The length and complexity of procedures and the comorbidities of the patient are the most important factors for sedation use. These factors may influence the choice of sedative, the level of sedation, and the need for an anesthesiologist during the procedure. Patients also vary in their sensitivity to sedation and their tolerance of endoscopy. The American Society of Anesthesiologists (ASA) defines the level of sedation on a spectrum of four recognizable levels, from minimal sedation to general anesthesia ( Table 7.1 ). The most commonly used level in endoscopic procedures is moderate sedation, wherein the patient demonstrates purposeful response to visual or tactile stimuli. This level of sedation can be achieved with a benzodiazepine alone or combined with an opiate. Due to the increased use of MAC, propofol use to target balanced propofol sedation (concurrent use with midazolam and/or fentanyl) is being increasingly used for mild to moderate sedation and is associated with improved patient outcomes.

TABLE 7.1

Levels of Sedation

From Bryson HM, Fulton BR, Faulds D: Propofol: an update of its use in anesthesia and conscious sedation. Drugs 50(3):513–559, 1995.

Level 1: Minimal sedation	Drug-induced state, during which patient responds normally to verbal commands. Cognitive function and coordination may be impaired. Ventilatory and cardiovascular function are unaffected
Level 2: Conscious sedation	Drug-induced depression of consciousness, during which patient responds purposefully to verbal commands, either alone or accompanied by light tactile stimulation. Patent airway is maintained without help. Spontaneous ventilation is adequate, and cardiovascular function is usually maintained
Level 3: Deep sedation	Drug-induced depression of consciousness, during which patient cannot be easily aroused but responds purposefully to repeated or painful stimulation. Patient may require assistance maintaining an airway. Spontaneous ventilation may be inadequate, and cardiovascular function is maintained
Level 4: General anesthesia	Patient is not able to be aroused even by painful stimuli. Patient often requires assistance in maintaining patent airway. Positive-pressure ventilation may be required owing to respiratory depression or neuromuscular blockade. Cardiovascular function may be impaired

This chapter focuses on all aspects of sedation and patient safety. Patient evaluation and risk assessment, presedation preparation, patient monitoring during sedation, sedation providers, sedation in high-risk populations, and issues of consent are discussed. The attributes of commonly used sedative drugs are discussed in the context of level of sedation and monitoring required.

Patient Evaluation, Preparation, and Risk Stratification

The risk of adverse outcomes can be reduced by appropriate preprocedural evaluation of the patient's history and physical findings. The clinicians responsible for sedation should familiarize themselves with specific and relevant aspects of the medical history, including abnormalities of major organ systems, previous adverse experience with sedation and analgesia, current medications and drug allergies, time of the last oral intake, and history of alcohol or recreational drug use. A thorough physical examination should be done, particularly to assess the heart and lungs, in addition to assessing the airway anatomy. It may be useful to consider the patient in terms of the ASA status classification ( Table 7.2 ), as increasing number and severity of comorbidities are associated with an increased incidence of cardiopulmonary unplanned events. Patients undergoing sedation should be informed of the benefits, risks, and limitations associated with sedation and possible alternatives. This should be completed as part of the patient consent.

TABLE 7.2

Definition of American Society of Anesthesiologists Status

Class 1	Patient has no organic, physiologic, biochemical, or psychiatric disturbance. Pathologic process for which operation is to be performed is localized and does not entail systemic disturbance
Class 2	Mild to moderate systemic disturbance caused either by the condition to be treated surgically or by other pathophysiologic processes
Class 3	Severe systemic disturbance or disease from whatever cause; it may be impossible to define degree of disability with finality
Class 4	Severe systemic disorders that are already life-threatening, not always correctable by operation
Class 5	Moribund patient who has little chance of survival but is submitted to operation in desperation

Patients undergoing sedation should be stratified according to the risk for sedation-related complications to receive either moderate sedation or MAC. The Stratifying Clinical Outcomes Prior to Endoscopy score (the SCOPE score) is a validated score that can be used to predict difficult moderate sedation for endoscopy based on several factors. The purpose of the risk stratification is to reduce the incidence of sedation-related adverse events.

Procedural Monitoring

Patients should have continuous monitoring while undergoing endoscopic procedures and also before, during, and after the administration of sedative agents. Standard monitoring procedures include electrocardiography, pulse oximetry, blood pressure measurement, and capnography. Monitoring should be discontinued only when the patient is fully awake. According to the ASA guidelines, it is recommended that continuous recording of the patient's level of consciousness, respiratory function, and hemodynamics reduces the risk of sedation-related adverse outcomes. Close monitoring helps in early detection of adverse events induced by sedatives, such as apnea, hypoxemia, hypotension, and arrhythmias, which allows for early intervention to prevent any life-threatening complications. Each of the monitored parameters is addressed in the following sections.

Level of Consciousness

Alteration in the level of consciousness while under sedation serves as a guide to the depth of sedation the patients. With a decrease in level of consciousness being associated with a loss of reflexes that normally protect the airway and prevent hypoventilation, it is important to assess patient response to commands during sedation (see Table 7.1 ). Verbal responses also provide information indicating that the patient is breathing. In procedures where verbal responses are impossible, such as upper GI endoscopy, nonverbal responses such as hand movements, finger squeezing, toe wiggling, etc., should be sought. A lack of response to verbal or tactile stimuli suggests a higher depth of sedation and should be managed accordingly.

Pulse Oximetry

A common noninvasive method of measuring oxygen saturation is pulse oximetry, which uses a light signal transmitted through tissue and takes into account the pulsatile volume changes that occur. The pulse oximeter measures the pulsatile signals across perfused tissue at two distinct wavelengths: the infrared band, which corresponds to oxyhemoglobin, and the red band, which corresponds to reduced hemoglobin.

However, the sole use of pulse oximetry is inadequate for detecting alveolar hypoventilation in patients undergoing endoscopy. This is demonstrated by the oxyhemoglobin dissociation curve. A high oxyhemoglobin concentration is preserved despite a decrease in partial pressure of oxygen in the blood (Pa o ₂ ) until the Pa o ₂ falls below 60 mm Hg, at which point the pulse oximeter reading reflects the decreasing Pa o ₂ with a rapid decrease in oxygen saturation. Therefore, alveolar hypoventilation is detected earlier with the use of capnography (described later) than pulse oximetry.

Pulmonary Ventilation

Respiratory depression in the form of transient hypoxemia is not uncommon with sedation use and is usually trivial. It is also encountered in unsedated procedures. Extended periods of hypoxemia, however, can cause tachycardia and coronary ischemia. Therefore, respiratory monitoring is very important to reduce the risk of adverse outcomes.

Direct observation of respiratory movement or direct pulmonary auscultation is the simplest way to monitor ventilator function. A noninvasive method for measuring arterial carbon dioxide is transcutaneous carbon dioxide monitoring (PtCO ₂ ), which entails placing a heated electrode on the skin, causing the microcirculation to “arterialize.” The eventual production of carbonic acid due to diffusion of carbon dioxide into an electrolyte solution provides a pH reading by using the Henderson-Hasselbalch equation, which allows for calculation of the arterial carbon dioxide level. The use of this technique was validated by Nelson et al (2000), who demonstrated significantly more CO ₂ retention in patients with standard monitoring than those with standard monitoring coupled with PtCO ₂ monitoring in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP).

Capnography is the gold standard for respiratory monitoring. It works by measuring the CO ₂ indirectly by virtue of light absorption in the infrared region of the electromagnetic spectrum. CO ₂ retention is identified as an early event on capnography and is a sign of ventilation compromise. It serves as a qualitative method for detection of CO ₂ levels in nonintubated patients undergoing endoscopy, as the exact measurement of CO ₂ is inaccurate unless the breathing system is a closed circuit, such as in intubated patients. There have been several studies that have demonstrated that use of capnography detects significantly more hypoxemia in patients undergoing GI endoscopy than standard monitoring. However, a 2016 trial did not demonstrate any reduction in the incidence of hypoxemia events in healthy individuals undergoing routine endoscopy targeting moderate sedation.

Bispectral index (BIS) monitors are often used in the operating room to assess the adequacy of the depth of anesthesia while under a general anesthetic in patients undergoing surgical procedures. However, the BIS monitor has significant overlap of scores across sedation levels when it is used to detect deep sedation, resulting in an overall lower accuracy rate.

Hemodynamic Measurements

Hemodynamic complications, such as hypotension, arrhythmias, and cardiovascular response to stress, are some of the mild direct effects of sedative agents and analgesics that may happen during sedation. Regular measurements of pulse and blood pressure can help detect these changes, which may represent responses to hypoxemia, oversedation, or possibly patient distress to procedure-induced pain. Although no evidence shows that blood pressure monitoring during endoscopy influences morbidity and mortality, it has been recommended that both regular blood pressure measurements and pulse be monitored throughout procedures performed under sedation. Continuous electrocardiogram (ECG) monitoring should be considered in high-risk patients, such as patients with known disturbances in cardiac rhythm, cardiomyopathies, or ischemic heart disease. The requirement for ECG monitoring has not been evaluated in clinical trials.

Supplemental Oxygen

Supplemental oxygen administered via nasal cannulas or a mask has been shown to reduce the incidence of desaturation during endoscopy performed under sedation and hence it should be given to all patients receiving sedation. However, as supplemental oxygen may delay the onset of hypoxemia in sedated patients with decreased pulmonary ventilation, it is essential not to rely solely on pulse oximetry to monitor ventilation but to employ additional techniques, such as capnography or a BIS monitor.

Intravenous Access

Intravenous access should be maintained throughout the procedure until the patient is no longer at risk from cardiopulmonary or respiratory depression. It facilitates the immediate availability of vascular access in the event of oversedation for administration of reversal agents or for using emergency drugs in the event of cardiopulmonary compromise. In patients who are receiving sedatives via nonintravascular routes (e.g., pediatric patients undergoing endoscopic procedures), intravenous access should also be obtained if the likelihood of any cardiopulmonary depression is high.

Sedation and Consent

There are a couple of important things to keep in mind when it comes to consent and sedation. First and foremost, the patient should be fully informed of the indications, risks, and alternatives to sedation before he or she consents to the procedure. The second important issue is whether a patient, while under sedation, can withdraw consent for the procedure. If a sedated patient indicates during endoscopy that he or she wishes to have the procedure stopped, should the endoscopist stop or complete the procedure, bearing in mind that it would be in the patient's best interests to complete it? A study from the United Kingdom researched this issue and found that 88% of gastroenterologists stated that they would only stop after repeated requests by the sedated patient, and only 45% of gastroenterologists thought patients were capable of making rational decisions while under sedation. When looked at from the patient's perspective, the study found that opinion was evenly divided into terminating the procedure immediately or completing it.

Staffing Levels and Training

Adequate patient monitoring during sedation is difficult for a clinician performing the procedure. There should be additional individuals available to monitor the patient's status in terms of level of consciousness, ventilatory function, and hemodynamic parameters. The presence of another individual is likely to improve patient comfort and satisfaction. Several areas of expertise are required while managing sedated patients, including knowledge of administered drugs and management of adverse events. All staff members administering sedative drugs should be made familiar with the pharmacology of all drugs used prior to their involvement. Particularly, staff members should be aware of the basics such as the time to onset of action, elimination half-life, interactions, adverse reactions, contraindications, and pharmacology of appropriate antagonists.

Individuals monitoring sedated patients should be able to recognize complications associated with the sedative drugs. Since most of the complications associated with sedatives are cardiopulmonary in nature, at least one individual should be familiar with advanced airway and ventilation management. Guidelines recommend an advanced resuscitation provider be immediately available in the event of an emergency. Resuscitation equipment should be readily available and must include a cardiac defibrillator, advanced airway and positive-pressure ventilation equipment, and all the appropriate drugs, including sedative antagonists ( Box 7.1 ).

Box 7.1

From American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists: Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 96(4):1004–1017, 2002.

Appropriate Emergency Equipment to Have Available When Using Sedative or Analgesic Drugs Capable of Causing Cardiorespiratory Depression

Appropriate emergency equipment should be available whenever sedative or analgesic drugs capable of causing cardiorespiratory depression are administered. The following lists should be used as a guide, which should be modified depending on the individual practice circumstances. Items in brackets are recommended when infants or children are sedated.

Intravenous Equipment

Gloves
Tourniquets
Alcohol wipes
Sterile gauze pads
Intravenous catheters [24–22-gauge]
Intravenous tubing [pediatric “microdrip” (60 drops/mL)]
Intravenous fluid
Assorted needles for drug aspiration, intramuscular injection (intraosseous bone marrow needle)
Appropriately sized syringes [1-mL syringes]
Tape

Basic Airway Management Equipment

Source of compressed oxygen (tank with regulator or pipeline supply with flowmeter)
Source of suction
Suction catheters [pediatric suction catheters]
Yankauer-type suction
Face masks [infant/child]
Self-inflating breathing bag-valve set [pediatric]
Oral and nasal airways [infant/child-sized]
Lubricant

Advanced Airway Management Equipment (for practitioners with intubation skills)

Laryngeal mask airways [pediatric]
Laryngoscope handles (tested)
Laryngoscope blades [pediatric]
Endotracheal tubes
- Cuffed 6.0, 7.0, 8.0 mm ID
- [Uncuffed 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0 mm ID]
Stylet (appropriately sized for endotracheal tubes)

Pharmacologic Antagonists

Naloxone
Flumazenil

Emergency Medications

Epinephrine
Ephedrine
Vasopressin
Atropine
Nitroglycerin (tablets or spray)
Amiodarone
Lidocaine
Glucose, 50% [10% or 25%]
Diphenhydramine
Hydrocortisone, methylprednisolone, or dexamethasone
Diazepam or midazolam

ID, internal diameter.

Postprocedural Monitoring

The patients remain at risk of sedative-related complications even after completion of the procedure. The risk of upper airway obstruction and hypoxemia after significant moderate sedation for ERCP seems to be greatest immediately after removal of the endoscope. Monitoring of the patient should be continued until the patient has reached an acceptable level of consciousness, with normal ventilation, oxygenation, and hemodynamic parameters. Before discharging the patient, it should be recognized that there may be a prolonged period of amnesia with impairment of cognition and judgment, even though the patient's conscious level may appear normal. Patients may also be mildly dehydrated, especially after colonoscopy, and fluid replacement should be addressed before discharge planning.

After an outpatient procedure, the following instructions should apply for at least 24 hours after discharge:

Patients should not drive.
Patients should not operate heavy or dangerous machinery.
Patients should not sign any legally binding documents.
Patients should be given written instructions regarding “warning signs and symptoms” of any adverse outcomes of the procedure and contact numbers for 24-hour advice.

In addition to the previous points, patients should arrange for a ride home beforehand, and that should be confirmed with the patient before starting the procedure.

In a placebo-controlled study, flumazenil use was shown to augment recovery from sedation and amnesia without any apparent risk for resedation. Although use of flumazenil adds to the costs of the procedure, it still may be preferable for some patients. Use of flumazenil does not preclude the need for postprocedural monitoring, and there is currently not enough evidence to support its routine use.

Drugs for Sedation

An ideal sedative agent should have the following characteristics:

Rapid onset of action
Practical means of delivery
Short half-life with rapid recovery
Safe with predictable sedative response (pharmacodynamics)
Minimal or no cardiovascular or respiratory effects
Effective in producing a calm, pain-free, cooperative patient

The most commonly used class of drugs are benzodiazepines, which are used alone or in combination with an opiate. It is vital that clinicians are familiar with a few specific sedatives (e.g., midazolam or fentanyl). Most recently, propofol has become the agent of choice to induce deep sedation. Midazolam and diazepam are also frequently used and have been shown to have similar efficacy when compared to each other. Midazolam is an attractive agent for endoscopy owing to its rapid onset of action, short half-life, and amnestic properties.

Fentanyl and meperidine are the most frequently used opiates, with fentanyl being preferred and commonly used because of its rapid action and absence of nausea.

The use of a benzodiazepine and an opiate is the most frequently utilized combination in endoscopic procedures, although this concurrent use may lead to an increased incidence of sedation-related complications. Combination therapy in colonoscopy and upper GI endoscopy, however, does not seem to improve pain and tolerance when compared with individual agents.

The safest method of administration is by giving small incremental doses until the desired level of sedation is attained, rather than giving a single bolus dose based on patient weight.

Droperidol used to be used in the sedation of agitated patients; however, due to its numerous side effects, it is not widely utilized anymore. Nitrous oxide has also been infrequently used as a form of patient-controlled analgesia in several studies involving colonoscopy. Potential benefits of its use include an absence of sedation-related risks and a rapid recovery. However, studies utilizing nitrous oxide were inconsistent and showed minimal to no benefit compared with traditional sedation.

Propofol and Deep Sedation

In certain circumstances, standard moderate sedation is not sufficient, and patients may require a higher level of sedation. These circumstances include patients who are not tolerant of endoscopy under moderate sedation and in procedures that are painful, longer, or complex, such as ERCP, endoscopic ultrasound (EUS), balloon enteroscopy, and endoscopic submucosal dissection (ESD). Deep sedation can be achieved with benzodiazepine and narcotic combinations. Fentanyl, remifentanil, and meperidine all have been combined with benzodiazepines and narcotics to accentuate sedative effects to achieve deep sedation.

Propofol is a popular drug that is frequently used for GI endoscopy because of its highly favorable pharmacokinetics. Its short half-life, rapid onset of action, rapid recovery times, and attainable depth of sedation make an attractive agent for endoscopic procedures. It has no analgesic properties. Patients who regularly use sedatives and narcotics are often insensitive to standard benzodiazepine sedation and may benefit from propofol sedation. There are several disadvantages associated with propofol use. Propofol has to be continuously titrated to maintain sedation due to its short half-life. The narrow therapeutic window between moderate sedation, deep sedation, and anesthesia necessitates close monitoring. As a result of peripheral vasodilation and impairment of cardiac contractility, propofol may cause profound hypotension. Propofol causes apnea more readily than midazolam, so managing the airway and pulmonary ventilation is more critical if propofol is used.

Newer Agents

Remimazolam is the latest drug innovation in anesthesia. It is an ester-based benzodiazepine designed to be used for short-duration sedation. It has an organ independent metabolism and is rapidly hydrolyzed by tissue esterases without producing any active metabolites. The sedation effect is shorter than midazolam, and frequent dosing may be required for procedure completion. Preliminary studies have suggested that the recovery time is similar to midazolam, although remimazolam recovery times lack the long outliers seen with midazolam sedation.

Fospropofol is a prodrug that is enzymatically converted to propofol in the liver with a delayed onset of action (4–8 min) and extended duration of action (20–30 min). It may decrease the need for frequent administration, which is often seen with propofol; however, because it needs to be converted to propofol, it has a decreased clinical effect compared to propofol. Fospropofol failed to gain popularity due to several inaccuracies that were reported in the published fospropofol pharmacokinetic-pharmacodynamic data. This led to the retraction of six studies, and correct data is yet to be made available.

Dexmedetomidine is an α ₂ -adrenoreceptor agonist with sedative, anxiolytic, and analgesic effects. Its effects on respiratory system are minimal, and it does not cause clinically significant respiratory depression. It can be administered either intranasally or intravenously, although the latter is preferred. Dexmedetomidine is delivered as an initial bolus infusion of 1 µg/kg over 10 min followed by continuous infusion of 0.6 µg/kg per hr that may be titrated between 0.2 to 1.0 µg/kg per hr. Dose modification is often necessary in elderly or critically ill patients. Side effects include bradycardia and a biphasic change in blood pressure (high then low) with administration of increasing concentrations. Dexmedetomidine alone or dexmedetomidine with meperidine and midazolam has shown to have less respiratory depression and higher patient satisfaction scores for routine endoscopy and more advanced procedures (e.g., ERCP) than midazolam alone or midazolam with meperidine. Dexmedetomidine causes less respiratory depression even when administered with propofol as compared to propofol administered with sufentanil, meperidine, or midazolam.

Sedation Providers

In the United States, moderate sedation is usually administered by an endoscopist, whereas anesthesiologists are the ones managing sedation for MAC or general anesthesia. There are several alternative methods of sedation for endoscopy, which include patient-controlled sedation (PCS), automated delivery using methods such as the SEDASYS system (Ethicon Endosurgery, Inc., Somerville, NJ), and nonanesthesiologist-administered sedation using centrally acting agents such as propofol.

Nearly all endoscopic procedures in the United States are completed with some form of sedation, whereas nearly three-fourths of all endoscopies performed in Europe and Asia are completed without sedation. The percentage of patients undergoing endoscopic procedures (simple or advanced) with MAC or deep sedation in the United States continues to rise. A national survey in 2006 concluded that roughly 75% of patients undergoing endoscopic procedures in the United States received moderate sedation and 25% received deep sedation. Presently, the regions with the highest anesthesiologist-administered sedation rates are the South and Mid-Atlantic states. Cooper et al (2013) showed that from 2000 to 2009, anesthesia services were used in 40% of the total endoscopies performed in the northeastern United States.

SEDASYS

In 2013, the US Food and Drug Administration (FDA) approved the SEDASYS system (Ethicon) for minimal to moderate sedation in ASA class 1–2 patients who are at least 18 years old and have a body mass index (BMI) less than 35 for elective esophagogastroduodenoscopy (EGD) and colonoscopy with a requirement that an anesthesiologist be “immediately available” in case of any complications. It was designed to be used with an initial fentanyl dose, followed by a propofol bolus delivered over 3 to 5 minutes, and then an adaptable propofol infusion. It had shown promise when compared with moderate sedation for endoscopy in low-risk patients, with better recovery times and greater satisfaction with SEDASYS among patients and clinicians. There is no direct comparison between SEDASYS and anesthesiologist-delivered sedation in the current literature. A very limited number of hospitals in the United States adopted SEDASYS. As a result, in May 2016, the manufacturer (Johnson & Johnson, New Brunswick, NJ) decided to remove it from the market due to a lack of popularity.

Patient-Controlled Sedation (PCS)

PCS uses the same hardware as patient-controlled analgesia with drugs (propofol, opioid, and/or benzodiazepines) chosen by the endoscopist. PCS has been shown to be successful in several small studies of both simple and advanced endoscopic procedures. Anesthesiologist-administered propofol and PCS have equal satisfaction for ERCP but with shorter recovery times and less frequent use of minor airway interventions, such as chin lifts, in the PCS group. In one study, anesthesiologist intervention was required to complete ERCP in 7% of PCS cases.

Gastroenterologist-Directed Propofol Sedation

Worldwide, gastroenterologists favor using propofol as a sedative for endoscopic procedures over traditional sedatives. In Switzerland, gastroenterologists administer propofol in both hospital and private practice settings, reflecting successful implementation of nonanesthesiologist-administered propofol-based sedation in other countries. A 2014 large German study of 24,441 endoscopic procedures with gastroenterologist-directed propofol sedation in ASA class 1–3 patients with BMI less than 40 and without obstructive sleep apnea (OSA) (ASA class 3 patients with cardiac issues were also excluded) concluded that the incidence rate for major adverse events (such as apnea or laryngospasm requiring mask ventilation or intubation) was only 0.016%, with the incidence of minor adverse events being just 0.46%. All affected patients made a full recovery. Anesthesia was titrated between moderate to deep sedation.

The latest guidelines of the European Society of Gastrointestinal Endoscopy for the administration of propofol for GI endoscopy by nonanesthesiologists consist of involving an anesthesiologist in high-risk patients, such as those with an ASA classification of 3 or higher, with a Mallampati score of 3 or higher, with conditions that put them at risk for airway obstruction, chronically receiving significant amounts of narcotics, or for whom a lengthy or a complicated procedure is anticipated.

The FDA regulations on propofol state, “For general anesthesia or MAC sedation, Diprivan Injectable Emulsion (Fresenius Kabi USA LLC, Lake Zurich, IL) should be administered only by persons trained in the administration of general anesthesia and not involved in the conduct of the surgical/diagnostic procedure.” This statement has grossly limited the use of propofol by nonanesthesia providers in the United States.

A fairly large 2017 meta-analysis found no difference in rates of overall complications between endoscopist-directed propofol administration and nonendoscopist-directed propofol administration.

Sedation in Different Patient Populations

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