In the United States, sedation and analgesia are the standard of practice when endoscopic procedures are performed in the ambulatory endoscopy center. Over the last 30 years, there has been a dramatic shift of endoscopic procedures from the hospital outpatient department to ambulatory endoscopy centers. This article will discuss sedation and analgesia in the ambulatory endoscopy center as it relates to optimizing safety, patient expectations, and efficiency.
Key points
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Optimizing safety is the responsibility of the endoscopist and gastrointestinal assistant of the 21st century. Each must have expertise in sedation and analgesia and patient monitoring.
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Patient expectations must be balanced with physician expectations and safety.
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The most efficient ambulatory endoscopy center will successfully navigate changes occurring in the health care system. Safety and efficiency must be viewed as 1 process.
In the United States, sedation and analgesia are the standard of practice when endoscopic procedures are performed in the ambulatory endoscopy center (AEC). Surveys indicate that physicians and patients expect that sedation and analgesia will routinely and safely be administered for endoscopic procedures. Over the last 30 years, there has been a dramatic shift of endoscopic procedures from the hospital outpatient department to AECs. This article will review sedation and analgesia in the AEC as it relates to optimizing safety, patient expectations, and efficiency.
Optimizing safety—preprocedure
The responsibilities of the endoscopist and gastrointestinal assistant of the 21st century reach beyond endoscopy. Each must have expertise in sedation and analgesia and patient monitoring, and awareness of potential complications.
Sedation may be defined as a medication-induced depression in the level of consciousness. The purpose of sedation and analgesia is to relieve patient anxiety and discomfort, improve the outcome of the examination, and diminish the patient’s memory of the event. Sedation and analgesia comprise a continuum of states ranging from minimal sedation (anxiolysis) to general anesthesia.
Table 1 outlines the definitions of the levels of sedation and analgesia. Historically, in the United States, endoscopic procedures in the AEC have been performed with patients under moderate sedation using benzodiazepines and narcotics.
| Minimal Sedation (Anxiolysis) | Moderate Sedation (Conscious Sedation) | Deep Sedation | General Anesthesia | |
|---|---|---|---|---|
| Responsiveness | Normal response to verbal stimulation | Purposeful response to verbal or tactile stimulation | Purposeful response after repeated or painful stimulation | Unarousable even with painful stimulus |
| Airway | Unaffected | No intervention required | Intervention may be required | Intervention often required |
| Spontaneous ventilation | Unaffected | Adequate | May be inadequate | Frequently inadequate |
| Cardiovascular function | Unaffected | Usually maintained | Usually maintained | May be impaired |
In the United States over the last 15 years, there has been a significant shift to deep sedation using propofol when performing endoscopic procedures in the AEC. In 2009, more than 30% of endoscopic procedures were performed under deep sedation utilizing anesthesia services. In 2015, most endoscopic procedures in AECs were performed under deep sedation utilizing anesthesia services.
Preprocedure preparation and assessment include appropriate discussion of the procedure and obtaining consent. This discussion should include indications, benefits, risks, and alternatives to the procedure. There are several other important preprocedure variables to assess and implement. According to the American Society of Anesthesiologists’ (ASA) practice guidelines for sedation and analgesia by nonanesthesiologists, patients should fast a minimum of 2 hours for clear liquids and 6 hours for a light meal.
A history and physical examination should be performed prior to endoscopy. The examination should focus on sedation and analgesia-related issues. The following data should be collected: (1) abnormalities of major organ systems; (2) snoring, stridor, or sleep apnea; (3) drug allergies, current medications, and potential for drug interactions; (4) prior adverse reaction(s) to sedatives or anesthetics; (5) time, and type, of last oral intake; and (6) tobacco, alcohol or substance abuse. The physical examination should include the following: measurement of vital signs, determination of baseline level of consciousness, and examination of the heart, lungs, and airway anatomy. Table 2 defines the ASA physical classification system.
| ASA PS Classification | Definition | Examples, Including, but Not Limited to: |
|---|---|---|
| ASA I a | A normal healthy patient | Healthy, nonsmoking, no or minimal alcohol use |
| ASA II a | A patient with mild systemic disease | Mild diseases only without substantive functional limitations Examples include (but not limited to): current smoker, social alcohol drinker, pregnancy, obesity (30< body mass index [BMI] <40), well-controlled DM/HTN, mild lung disease |
| ASA III a | A patent with severe systemic disease | Substantive functional limitations; one or more moderate-to-severe diseases Examples include (but not limited to): poorly controlled DM or HTN, chronic obstructive pulmonary disease, morbid obesity (BMI ≥40), active hepatitis, alcohol dependence or abuse, implanted pacemaker, moderate reduction of ejection fraction, end-stage renal disease undergoing regularly scheduled dialysis, premature infant PCA <60 wk, history (>3 mo) or myocardial infarction, CVA, TIA, or CAD/stents. |
| ASA IV a | A patient with severe systemic disease that is constant threat to life | Examples include (but not limited to): recent (<3 mo) MI, CVA, TIA, or CAD/stent, ongoing cardiac ischemia or severe valve dysfunction, severe reduction of ejection fraction, sepsis, DIC, ARD, or ESRD not undergoing regularly scheduled dialysis |
| ASA V a | A moribund patient who is not expected to survive without the operation | Examples include (but not limited to): ruptured abdominal/thoracic aneurysm, massive trauma, intracranial bleed with mass effect, ischemic bowel in the face of significant cardiac pathology or multiple organ/system dysfunction |
| ASA VI a | A declared brain-dead patient whose organs are being removed for donor purposes | — |
a The addition of “E” denotes Emergency surgery: (an emergency is defined as existing when delay in treatment of the patient would lead to a significant increase in the threat to life or body part).
Optimizing safety—preprocedure
The responsibilities of the endoscopist and gastrointestinal assistant of the 21st century reach beyond endoscopy. Each must have expertise in sedation and analgesia and patient monitoring, and awareness of potential complications.
Sedation may be defined as a medication-induced depression in the level of consciousness. The purpose of sedation and analgesia is to relieve patient anxiety and discomfort, improve the outcome of the examination, and diminish the patient’s memory of the event. Sedation and analgesia comprise a continuum of states ranging from minimal sedation (anxiolysis) to general anesthesia.
Table 1 outlines the definitions of the levels of sedation and analgesia. Historically, in the United States, endoscopic procedures in the AEC have been performed with patients under moderate sedation using benzodiazepines and narcotics.
| Minimal Sedation (Anxiolysis) | Moderate Sedation (Conscious Sedation) | Deep Sedation | General Anesthesia | |
|---|---|---|---|---|
| Responsiveness | Normal response to verbal stimulation | Purposeful response to verbal or tactile stimulation | Purposeful response after repeated or painful stimulation | Unarousable even with painful stimulus |
| Airway | Unaffected | No intervention required | Intervention may be required | Intervention often required |
| Spontaneous ventilation | Unaffected | Adequate | May be inadequate | Frequently inadequate |
| Cardiovascular function | Unaffected | Usually maintained | Usually maintained | May be impaired |
In the United States over the last 15 years, there has been a significant shift to deep sedation using propofol when performing endoscopic procedures in the AEC. In 2009, more than 30% of endoscopic procedures were performed under deep sedation utilizing anesthesia services. In 2015, most endoscopic procedures in AECs were performed under deep sedation utilizing anesthesia services.
Preprocedure preparation and assessment include appropriate discussion of the procedure and obtaining consent. This discussion should include indications, benefits, risks, and alternatives to the procedure. There are several other important preprocedure variables to assess and implement. According to the American Society of Anesthesiologists’ (ASA) practice guidelines for sedation and analgesia by nonanesthesiologists, patients should fast a minimum of 2 hours for clear liquids and 6 hours for a light meal.
A history and physical examination should be performed prior to endoscopy. The examination should focus on sedation and analgesia-related issues. The following data should be collected: (1) abnormalities of major organ systems; (2) snoring, stridor, or sleep apnea; (3) drug allergies, current medications, and potential for drug interactions; (4) prior adverse reaction(s) to sedatives or anesthetics; (5) time, and type, of last oral intake; and (6) tobacco, alcohol or substance abuse. The physical examination should include the following: measurement of vital signs, determination of baseline level of consciousness, and examination of the heart, lungs, and airway anatomy. Table 2 defines the ASA physical classification system.
| ASA PS Classification | Definition | Examples, Including, but Not Limited to: |
|---|---|---|
| ASA I a | A normal healthy patient | Healthy, nonsmoking, no or minimal alcohol use |
| ASA II a | A patient with mild systemic disease | Mild diseases only without substantive functional limitations Examples include (but not limited to): current smoker, social alcohol drinker, pregnancy, obesity (30< body mass index [BMI] <40), well-controlled DM/HTN, mild lung disease |
| ASA III a | A patent with severe systemic disease | Substantive functional limitations; one or more moderate-to-severe diseases Examples include (but not limited to): poorly controlled DM or HTN, chronic obstructive pulmonary disease, morbid obesity (BMI ≥40), active hepatitis, alcohol dependence or abuse, implanted pacemaker, moderate reduction of ejection fraction, end-stage renal disease undergoing regularly scheduled dialysis, premature infant PCA <60 wk, history (>3 mo) or myocardial infarction, CVA, TIA, or CAD/stents. |
| ASA IV a | A patient with severe systemic disease that is constant threat to life | Examples include (but not limited to): recent (<3 mo) MI, CVA, TIA, or CAD/stent, ongoing cardiac ischemia or severe valve dysfunction, severe reduction of ejection fraction, sepsis, DIC, ARD, or ESRD not undergoing regularly scheduled dialysis |
| ASA V a | A moribund patient who is not expected to survive without the operation | Examples include (but not limited to): ruptured abdominal/thoracic aneurysm, massive trauma, intracranial bleed with mass effect, ischemic bowel in the face of significant cardiac pathology or multiple organ/system dysfunction |
| ASA VI a | A declared brain-dead patient whose organs are being removed for donor purposes | — |
a The addition of “E” denotes Emergency surgery: (an emergency is defined as existing when delay in treatment of the patient would lead to a significant increase in the threat to life or body part).
Patient expectations—sedation and analgesia
Historically, in the United States, moderate sedation and analgesia for endoscopic procedures were the standard of practice. Today, at least half of endoscopic procedures in the AEC are performed with monitored anesthesia care (MAC) targeting deep sedation. One of the factors leading to an increased use of MAC is patient expectation for comfort and lack of memory for the procedure. General patient expectations are similar to physician expectations: safety and comfort during endoscopy. However, many patients place more emphasis on comfort during endoscopic procedures. As patients do not fully understand the many factors involved in patient safety and performing a quality endoscopic procedure, it is important for AEC staff and endoscopists to communicate to the patient the many variables (medications, monitoring equipment, and efficiency) that affect safety, comfort, and quality in endoscopy. Safety, quality, and comfort extend beyond the actual performance of the procedure; these three factors apply to the entire experience as patients move through the AEC for the duration of their endoscopic visit.
The ideal medication for sedation and analgesia should have a rapid onset of action and produce a predictable effect. It should not precipitate cardiopulmonary decompensation. Finally, it should lead to amnesia for the period of time during which the procedure is performed and extend into the postprocedure recovery period. Ideally, the medication should be administered by the endoscopy nurse and have an acceptable safety profile. A drug such as this would meet all patient and endoscopist expectations.
Medications
Currently, the ideal medication for sedation and analgesia for endoscopic procedures does not exist. The most common medications used for sedation and analgesia include benzodiazepines, narcotics, and propofol. Regardless of who administers the medication (nurse, endoscopist, nurse anesthetist, or anesthesiologist), the endoscopist must be familiar with all drugs given for endoscopic procedures.
Benzodiazepines
Midazolam is the most commonly used benzodiazepine for sedation and analgesia during endoscopy. It is a sedative hypnotic that causes varying degrees of amnesia. Midazolam reaches its peak effect quickly (approximately 3–5 minutes) and has an elimination half-life of 1 to 4 hours in healthy individuals. In older patients and in those with significant comorbid disease, the half-life of may be prolonged. A typical starting dose for midazolam is 0.5 to 2 mg intravenously; subsequent dosing should be administered in 1 mg increments.
Midazolam causes antegrade amnesia. It may cause hypoventilation, which may lead to lower oxygen saturation. Hypoventilation is believed to be secondary to depression of the respiratory center in the brainstem. In general, benzodiazepines have minimal effect on the cardiovascular system. With marked sedation, there is some peripheral vasodilation and a slight drop in cardiac output and peripheral resistance. Subsequently, hypotension may develop.
Opioids
Fentanyl is the most commonly used opioid analgesic for sedation and analgesia during endoscopic procedures. It’s typically combined with benzodiazepines. Fentanyl has a mild sedative effect and decreases the intensity of painful stimuli. It reaches its peak effect in approximately 5 minutes and has a duration of action of 1 to 3 hours. A typical starting dose for fentanyl is 50 to 100 μg intravenously; subsequent dosing should be administered in 25 to 50 μg increments. The major adverse effects of fentanyl are respiratory depression with hypoxemia and CO 2 retention. Respiratory depression results from central depression of ventilatory response to CO 2 and decreased respiratory rate with or without decreased tidal volume.
In the United States, fentanyl is not routinely used alone because of its minimal sedative effect. Opioid analgesics are generally used in combination with benzodiazepines. Combining opioid analgesics and benzodiazepines lead to a rapid and reliable induction of sedation, synergistic and additive effects, enhanced patient tolerance of the procedure, and increased ability for the physician to complete the procedure. Combining opioid analgesics and benzodiazepines increases the potential for an adverse event. The addition of opioid analgesics to benzodiazepines has a synergistic effect on respiratory depression and hypoxemia. Because of these additive and synergistic effects, reduced doses should be used when combining these drugs. In general, when combining these agents, the opioid analgesic should be administered first, followed by the benzodiazepines, using smaller doses of each compared with using either drug alone.
Propofol
Propofol is classified as a short-acting sedative, amnestic, and hypnotic that provides minimal analgesia. The peak effect occurs quickly, in 30 to 60 seconds, and the half-life is 1.8 to 4.1 minutes. These properties account for a quick recovery time after cessation of propofol, generally 10 to 30 minutes. Propofol can be administered as a single bolus or continuous infusion and has been studied alone and in combination with benzodiazepines and opioid analgesics for endoscopy. When propofol was combined with opioid analgesics or benzodiazepines, patients reported better tolerance of the procedure and reached a deeper level of sedation. There was no increase in adverse events when comparing the combination of propofol and fentanyl with midazolam and meperidine. Advantages of propofol include better tolerance of endoscopy, deeper level of sedation, and more rapid recovery time. Disadvantages of propofol include pain at the injection site, shorter amnesia span, and less analgesia. One final disadvantage of propofol is the cost, which is higher compared with opioid analgesics and benzodiazepines. The increased cost is secondary to medication cost and the use of an anesthesia professional. Table 3 summarizes the medication use and adverse effects. Adverse effects of propofol include respiratory depression, a reduction in systemic vascular resistance with possible hypotension, and pain on venous injection.
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