Moderate Sedation: What Radiologists Need to Know

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1 Noninterpretive Skills Review Olsen et al. What Radiologists Need to Know About Moderate Sedation Noninterpretive Skills Review FOCUS ON: Jonathan W. Olsen 1 Richard L. Barger, Jr. 2 Shashin K. Doshi 1 Olsen JW, Barger RL Jr, Doshi SK Keywords: conscious sedation, moderate sedation, sedation practice guidelines DOI: /AJR Received June 28, 2012; accepted after revision January 31, Department of Diagnostic Radiology, William Beaumont Hospital, 3601 W Thirteen Mile Rd, Royal Oak, MI Address correspondence to J. W. Olsen (Jonathan.Olsen@beaumont.edu). 2 University Hospitals of Cleveland Case Medical Center, University Hospitals Geauga Medical Center, Chardon, OH. CME/SAM This article is available for CME/SAM credit. AJR 2013; 201: X/13/ American Roentgen Ray Society Moderate Sedation: What Radiologists Need to Know OBJECTIVE. The number of procedures conducted within the radiology department using moderate sedation is rising. Anecdotal evidence suggests that there is an inconsistency in the education of radiology trainees regarding moderate sedation. CONCLUSION. The purpose of this article is to give an overview and concise summary of the use of moderate sedation as put forth by the American Society of Anesthesia, American College of Radiology, and Society of Interventional Radiology. In addition, we will review the commonly used medications for moderate sedation and their reversal agents. T here are approximately 274 therapeutic radiologic procedures performed per 1000 Medicare patients per year. This number is increasing annually, and the procedures are becoming increasingly complex [1]. Many of these procedures potentially require pain control greater than local anesthesia. Moderate sedation is an option for radiologists to provide their patients a level of sedation and analgesia that does not necessarily require the supervision of an anesthesiologist. The American College of Radiology (ACR), in conjunction with the Society for Interventional Radiology (SIR), has developed guidelines for the proper use of sedation and analgesia [2]. However, credentialing of the supervising radiologist to perform such procedures is ultimately left to the institution where the radiologist has privileges. The inherent differences between institutional guidelines and limited resident clinical experience and formal education regarding moderate sedation result in a significant variance in resident education. We will provide an overview of the use of moderate sedation in radiology as put forth by the American Society of Anesthesiologists (ASA), ACR, and SIR. In addition, we will review the commonly encountered medications used for moderate sedation. Consideration will be given to the practice standards for institutional credentialing set forth by The Joint Commission. ASA Guidelines To create practice guidelines for sedation and analgesia by nonanesthesiologists [3], the ASA appointed 10 task force members to review published literature, obtain the opinions of a panel of consultants (both anesthesiologists and nonanesthesiologists who routinely administer moderate sedation), and build consensus within the community of practitioners likely to be affected by the guidelines. The practice guidelines represent a set of recommendations on topics pertaining to the evaluation, management, and discharge of patients undergoing moderate sedation for a procedure. It should be highly stressed that the practice guidelines were developed to assist the practitioner in making clinical decisions and are not intended to be standards or absolute requirements [3]. Previously, moderate sedation was known as conscious sedation. The term was altered to better fit within the spectrum of sedation and analgesia presented by the ASA. By definition, moderate sedation represents a minimally depressed level of consciousness induced by the administration of pharmacologic agents in which the patient retains a continuous and independent ability to maintain protective reflexes, a patent airway, and the ability to be aroused by physical or verbal stimulation [3]. Moderate sedation, in relation to other ASA-defined levels of sedation, is summarized in Table 1. ACR-SIR Guidelines Similarly, the ACR-SIR practice guidelines for sedation and analgesia [2] represent the latest revision of collaboration between the ACR and the SIR to offer guidelines designed to assist in the safe administration of sedation AJR:201, November

2 Olsen et al. TABLE 1: American Society of Anesthesiologists Classification for Sedation and Analgesia Criterion Responsiveness Minimal Sedation (Anxiolysis) Normal response to verbal stimuli and analgesia outside the operating room. The guidelines were produced using the standard ACR process for developing standards and guidelines, including allowing practicing radiologists in the community to add their input. Again, these guidelines are provided to assist in patient care and are not inflexible rules or requirements [2]. Preprocedural Evaluation The preprocedural evaluation of the patient and his or her medical history is an important part of safe sedation. Radiologists administering sedation and analgesia must be familiar with relevant aspects of the patient s medical history and physical examination and how these factors might alter the patient s response to sedation and analgesia, including abnormalities of the major organ systems; previous adverse experience with sedation and analgesia (considering both regional and general anesthesia); drug allergies; current medications; potential drug interactions; time and nature of last oral intake; history of tobacco, alcohol, or substance use or abuse; airway evaluation; and the presedation risk assessment using the ASA physical status classification system [3]. ASA Physical Status Classification System The ASA physical status classification system was designed for the risk stratification of patients before sedation on the basis of the severity of existing systemic disease. Class 1 is defined as a normal healthy patient. Classes 2 and 3 are patients with mild and moderate systemic disease, respectively. Examples of mild systemic diseases are controlled hypertension, mild diabetes, or morbid obesity. A moderate systemic disease is considered more impactful on the patient s everyday life, such as chronic obstructive pulmonary disorder or myocardial infarction. Class 4 is a patient with severe systemic disease that is a constant threat to life, such Moderate Sedation and Analgesia (Conscious Sedation) Deep Sedation and Analgesia General Anesthesia Purposeful response to verbal or tactile stimulation as heart or renal failure. A patient with a ruptured aneurysm would be considered class 5, a moribund patient who is not expected to survive without the procedure. The ACR-SIR practice guidelines do stratify patients on the basis of the ASA classification. Classes 1 and 2 are considered low risk, and no further recommendations are made before initiation of moderate sedation, whereas classes 3 and 4 may require further consideration, such as consultation with an anesthesiologist. As the ASA class increases, so does the risk of complication; the radiologist needs to give strong consideration to the risks and benefits of proceeding with the class 3 and 4 patients. According to the ACR- SIR practice guidelines, moderate sedation should not be performed by a nonanesthesiologist on ASA class 5 patients [2]. Mallampati Score The risk of encountering a situation in which the patient would require intubation is present in all procedures using sedation. The operator can evaluate the patient s oropharynx to assess the potential difficulty of intubation before initiating sedation by using the modified Mallampati scoring system [4]. The ability to visualize various combinations of the soft palate, faucial pillars, and uvula yields a score of 1 through 3. The higher scores correlate with more difficult intubations. On the basis of the modified Mallampati score, the radiologist may choose to have an anesthesiologist present to preemptively intubate the patient and manage the sedation. Purposeful response after repeated or painful stimulation Unable to be aroused, 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 Note Excerpted from American Society of Anesthesiologists (ASA) Task Force on Sedation and Analgesia by Non-Anesthesiologists: Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 2002; 96: A copy of the full text can be obtained from ASA, 520 N. Northwest Highway, Park Ridge, Illinois Fasting To allow gastric emptying, patients should not drink fluids or eat solid foods for a sufficient amount of time before moderate sedation (Table 2). Emergent or urgent procedures may not allow adequate fasting, and the potential for pulmonary aspiration of gastric contents must be considered when determining the target level of sedation, whether the procedure can or should be delayed, and whether the trachea should be protected by intubation [2]. Medications Various medications can be used to achieve moderate sedation, and the ASA and ACR- SIR do not offer guidelines on the proper administration of such medications. We include this section for completeness and expect more detailed education regarding the practical application during training (Table 3). Benzodiazepines Benzodiazepines are a centrally acting class of medication that cause sedation and hypnosis, decreased anxiety, and increased muscle relaxation. They also cause antegrade amnesia and have anticonvulsant properties. There is minimal associated respiratory depression in healthy adults, but care needs to be taken with children, elderly patients, and those with impaired hepatic function, given the mode of metabolism. Apnea may occur when they are given in conjunction with prior administration or ingestion of opioid medications or CNS depressants (especially ethanol). They may worsen sleep-related disorders, such as obstructive sleep apnea, by reducing control of the upper airway muscles. Because of their large volume of distribution, their effects are more pronounced in pediatric and geriatric populations. These medications can cross the placenta and are excreted in breast milk [5]. Midazolam (Versed, Roche Laboratories) is a short-acting benzodiazepine with a time to onset of 1 3 minutes and duration of approximately 1 hour [6]. The short-acting sedative effect and rapid onset and recovery make this a commonly used medication [7]. There have been rare reports of paradoxical reactions with midazolam appearing as agitation, involuntary tonic or clonic movements, tremors, hy- 942 AJR:201, November 2013

3 What Radiologists Need to Know About Moderate Sedation peractivity, and combativeness. The operator should first assess whether poor sedation or analgesia is responsible for reactions before adjusting to another medication [8]. This medication should be given in small incremental doses and titrated to the desired effects; no more than 1 mg is the typical dose [7, 8]. Diazepam (Valium, Roche Laboratories) is longer acting, with a time to onset of 2 3 minutes and a duration of 6 hours. This medication can be titrated to a desired effect, but the longer duration of effect limits its usefulness in the ambulatory setting [7]. Administration of 1 2 mg up to 10 mg is usually sufficient for moderate sedation [8]. Lorazepam (Ativan, Biovail Pharmaceuticals) is the longest lasting of the benzodiazepines reviewed here, with duration of up to hours, which limits its utility for intraprocedural maintenance [6, 8]. Two milligrams of lorazepam can be given orally before the procedure, approximately minutes, to aid with induction [8]. However, the time to onset can be as long as minutes [7]. TABLE 2: American College of Radiology Society of Interventional Radiology Recommended Fasting Guidelines for Children and Adults Patient Age Group Solids and Nonclear Liquids Clear Liquids Adults 6 8 hours 2 4 hours Children > 36 months old 6 8 hours 2 4 hours Children 6 36 months old 6 hours 2 4 hours Children < 6 months old 4 6 hours 2 hours Note Complete guidelines were published elsewhere [2]. Opioids Opioid medications are used when adequate analgesia cannot be achieved with local anesthesia. These drugs bind to endogenous opioid receptors in the CNS and peripheral nervous system, causing hyperpolarization of the nerves. Their most common side effects are nausea, vomiting, and dysphoria. Opioid medications can have an associated histamine release, causing pruritus or cutaneous rash. The most concerning side effects are cardiovascular and respiratory depression. Opioid medications do have an associated sedative property, and caution should be used when administering opioids at the same time as benzodiazepines [9]. Morphine (morphine sulfate) is considered the standard against which all other opioid medications are compared. It is long acting, with a time to onset of less than 10 minutes and a duration of up to 4 hours [8]. Doses of 2 mg are typical [7]. Again, a longer duration of effect does limit the use of morphine [8]. Of note, its metabolite, morphine-6-glucuronide, is twice as potent as the parent compound and is excreted renally. Therefore, patients with renal failure can experience prolongation of the effects expected with morphine, including any associated cardiovascular and respiratory depression [9]. Fentanyl (fentanyl citrate) is relatively short acting with a time to onset of 2 3 minutes and a duration of minutes [6, 7]. The lack of an associated histamine release limits blood pressure reduction; thus, fentanyl is considered cardiovascularly stable [9]. Fentanyl is given in 25-µg increments and is favorable for analgesia in moderate sedation because of its rapid onset and fitting duration of action [7]. Hydromorphone (Dilaudid, Purdue Pharma) is similar in profile to morphine, with a time to onset of 10 minutes and a duration of 4 5 hours [8]. Hydromorphone does not have an active metabolite, but it is associated with increased CSF pressure [8]. Compared with the prototypical opioid, morphine, hydromorphone is associated with relatively less nausea, vomiting, constipation, and euphoric effects [10]. Meperidine (Demerol, Sanofi Aventis) is a synthetic opioid analgesic with a shorter duration than morphine. The effects of meperidine can last 2 4 hours [8]. Using incremental doses of mg, the time to onset can range from 5 to 15 minutes [11]. Care needs to be used when administering meperidine to a patient with a history of cardiac disease, because it has vagolytic properties that tend to increase the ventricular response [10]. Other Analgesic Medication Ketorolac (Toradol, Roche Pharmaceuticals) is a nonsteroidal antiinflammatory drug that can be used for analgesia. Ketorolac can be given intramuscularly, where it has known kinetics with a time to onset of 10 minutes and duration of 6 8 hours, when a dose of mg is given [10]. Ketorolac can be given to patients as an oral prescription after procedures, and it should not be prescribed for greater than 5 days [8, 10]. Similar to other nonsteroidal antiinflammatory drugs, ketorolac has antipyretic, analgesic, and antiinflammatory effects from the inhibition of cyclooxygenase and reduction in prostaglandin synthesis. Importantly, there are no reported interactions when it is coadministered with opioid and benzodiazepine classes [10]. This medication is contraindicated for patients with peptic ulcer disease and gastrointestinal bleeding [8]. With this is mind, ketorolac is not benign; rare adverse reactions comprising abnormal thinking, euphoria, poor concentration, and urinary retention have been reported in less than 1% of cases, whereas headache, somnolence, and dizziness have been reported in 17%, 3 14%, and 3 9% of cases, respectively [7, 10]. Renal toxicity can occur, and care should be taken when considering this class of medications in patients with renal impairment, dehydration, or liver disease or those who are receiving diuretic therapy [7, 8]. Reversal Agents Both benzodiazepine and opioid classes of medications have reversal agents that the administering physician should be familiar with in case of an emergency. In the case of benzodiazepines, overdose is characterized by deep sedation, dampened response to external stimuli, and prolonged emergence from sedation with possible hypotension [11]. Flumazenil (Romazicon, Roche Laboratories) is the reversal agent for benzodiazepines. Flumazenil should be administered over a series of small injections (200 µg, up to a total dose of 1 mg). The operator should wait 1 minute between injections, watching for a response in a patient experiencing a benzodiazepine overdose. Resedation can occur, because the duration of action is only minutes, possibly requiring reinjection and airway support [5]. Opioid overdose is characterized by suppression of respiratory drive, deep sedation, hypotension, and significant nausea and vomiting. Naloxone (Narcan, Endo Pharmaceuticals) is the reversal agent for opioids, with a standard dose for an adult of mg IV every seconds (no maximum). At this dose, there is typically reversal of apnea without complete reversal of analgesia. Naloxone has a short duration of action, minutes, which is much less than most opioids. Relapse of opioid sedation can occur, and a continuous infusion may be considered, at a rate of 2 5 µg/kg/hr [11]. AJR:201, November

4 Olsen et al. Personnel Per the ACR-SIR guidelines [2], sedation and analgesia should be conducted under the supervision of a licensed physician. All persons administering sedation and analgesia are responsible for maintaining proficient skills necessary to provide adequate patient care. Appropriately trained medical personnel should be available in case of adverse events. There are several defined roles for medical personnel involved in moderate sedation [2]. Supervising Physician The supervising physician must have sufficient knowledge of pharmacology, indications, and contraindications of moderate sedation medications. The operator should be able to recognize and initiate treatment of adverse reactions, including the use of reversal agents. All supervising physicians must maintain current basic life support (BLS) certification. The majority of radiologic procedures requiring moderate sedation involve adult patients, and the supervising physician should have up-to-date training and certification in advanced cardiac life support or should have access to an individual with advanced cardiac life support certification with a response time of less than 5 minutes. For pediatric patients, the supervising physician should also have current pediatric advanced life support certification. Finally, the supervising physician should meet credentialing requirements of the facility and have privileges to perform moderate sedation [2]. Patient Monitor The health professional whose primary role is to monitor the patient does not necessarily have to be a physician. This role may be fulfilled by a physician, registered nurse, advanced practice nurse, registered radiology assistant, or other qualified individual besides the operator, and that individual must be present throughout the procedure. This individual must meet facility requirements, have current BLS certification, and be knowledgeable in the use, side effects, and complications of the appropriate medications. This individual s primary responsibility is to monitor the patient throughout the procedure, and therefore it is essential that the person is knowledgeable and experienced in monitoring vital signs, including pulse oximetry and recognizing cardiac dysrhythmias. This individual may administer medications and assist with minor interruptible tasks [2]. In-Procedure Monitoring The ACR-SIR guidelines [2] provide specific recommendations for the in-procedure monitoring and management during moderate sedation. First, IV access must be maintained. Second, homeothermia should be preserved. Third, patients should be protected from pressure-related and position-related injuries. Fourth, all patients should be continuously monitored throughout the procedure by physiologic measurements that should be recorded (at least every 5 minutes). These measurements include, but are not limited to, level of consciousness, respiratory rate, pulse oximetry, blood pressure (as indicated), heart rate, and cardiac rhythm. Fifth, supplemental oxygen with size-appropriate equipment should be immediately available and administered as needed. Sixth, suction should be immediately available. Seventh, a defibrillator with back-up emergency power and emergency cart, including equipment for intubation and ventilation, should be immediately avail- TABLE 3: Common Medications Used in Moderate Sedation Time to Class, Medication Dose a Onset (min) Duration Metabolism Excretion Active Metabolite Pregnancy Category Benzodiazepine Midazolam < 1.0 mg hour Hepatic Renal None D Diazepam mg hours Hepatic Renal Desmethyldiazepam D Lorazepam 2.0 mg by mouth Up to hours Hepatic Renal None D Opioid Morphine 2.0 mg 10 4 hours Hepatic Renal Morphine-6-glucuronide C Fentanyl 25 µg minutes Hepatic Renal None C Hydromorphone 1.0 mg; use the smallest hours Hepatic Renal None C effective Meperidine mg hours Hepatic Renal Normeperidine C mg intramuscularly Hepatic 90% renal; 6% biliary None C (1st and 2nd trimesters); D (3rd trimester) Nonsteroidal antiinflammatory drug, ketorolac minutes C 200 µg, every minute up to 1 mg Benzodiazepine antagonist, flumazenil Rapid minutes C Opioid reversal agent, naloxone mg every seconds Note C = animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks; D = positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.. a Doses are administered IV, unless indicated otherwise. 944 AJR:201, November 2013

5 What Radiologists Need to Know About Moderate Sedation able. Eighth, the route, dosage, and time of all sedation and reversal medications administered should be documented on the sedation record by the health professional responsible for monitoring the patient. Ninth, drug antagonists and IV fluids should be immediately available; their use should be based on the clinical circumstances. Tenth, sufficient time must elapse between doses to allow the effect of each dose to be assessed before subsequent drug administration. Eleventh, in adult patients, IV sedative and analgesic drugs are given in incremental doses that are titrated to the desired endpoints of sedation and analgesia. Finally, combinations of sedative and analgesic agents should be administered as appropriate for the procedure being performed and the medical condition of the patient. Ideally, each component should be administered individually to achieve the desired effect (e.g., additional analgesic mediation to relieve pain and additional sedative medication to decrease awareness or anxiety). Complications Despite appropriate administration of sedation and analgesia, complications may occur. The following is a brief summary of common possible situations and suggested solutions. There are times when patient agitation may persist after the start of sedation. It is important to allow adequate time for medications to take effect, to ask whether the patient is in a comfortable position, and to ask the patient whether pain or anxiety is the cause of distress so that the appropriate action can be taken. In some cases, sedation causes confusion or disorientation, which may lead to agitation and restlessness. These patients may need to be rescheduled when higher levels of sedation are available [11]. In cases of hypotension, IV fluids should be readily available, with the choice of fluid dependent on the institution and physician conducting the procedure. Hypotension can result from the medications used for sedation and analgesia. However, the operator needs to be aware of additional causes such as sepsis or bleeding. Vasopressor use may be indicated, and consideration for critical care and anesthesia consultation may be helpful [11]. Oxygen desaturation is another problem commonly encountered during moderate sedation. Factors that may indicate an upper airway obstructive process should be considered first, such as snoring or grunting, obesity, or a history of apnea. Supplemental oxygen should be available at all times and used freely if the patient desaturates. Commonly, 2 L by nasal cannula is attempted initially. If the patient is cooperative, encourage him or her to breathe deeply. Otherwise, the standard BLS maneuver to improve head position with chin lift jaw thrust may be used. Suction should be used to clear the airway if the patient has visible blood, vomitus, or secretions in the oropharynx. Oversedation, with either opioids or benzodiazepines, can cause a decrease in oxygen saturation, and the use of a reversal agent should be considered. Again, maintain a threshold for getting assistance depending on experience, because some radiologists may not be comfortable placing an advanced airway tube, such as an endotracheal tube. Nausea and vomiting are known side effects of several medications used in moderate sedation. [5, 8, 10,] The use of antiemetics can help the patient relax and maintain comfort throughout the procedure. However, always have suction available in case the patient does vomit, obstructing the airway. Some patients may experience excessive or prolonged sedation with any of the medications used during moderate sedation. These patients will usually do well on their own with continuous monitoring from the nursing staff in the holding area with supplemental oxygen available. Reversal agents may be considered in cases when the prolonged sedation may result in other complications [6, 11]. Recovery Care All patients should be evaluated by a qualified health professional after the procedure and before discharge. The ASA offers general principles to be considered in the recovery area [3]. First, medical supervision of recovery and discharge after moderate sedation is the responsibility of the operating practitioner or a licensed physician. Second, the recovery area should be equipped with, or have direct access to, appropriate monitoring and resuscitation equipment. Third, patients receiving moderate sedation should be monitored until appropriate discharge criteria are satisfied. The duration and frequency of monitoring should be individualized depending on the level of sedation achieved, the overall condition of the patient, and the nature of the intervention for which sedation or analgesia was administered. Oxygenation should be monitored until patients are no longer at risk for respiratory depression. Fourth, level of consciousness, vital signs, and oxygenation should be recorded at regular intervals. Fifth, a nurse or other individual trained to monitor patients and recognize complications should be in attendance until discharge criteria are fulfilled. Finally, an individual capable of managing complications (e.g., establishing a patent airway and providing positive pressure ventilation) should be immediately available until discharge criteria are fulfilled. Discharge Criteria Most institutions will have a discharge checklist that should be used to assess the readiness of the patient for discharge. Again, the ASA has specific guidelines that should be included in the checklist and used when discharging the patient [3]. First, patients should be alert and oriented; patients whose mental status was initially abnormal should have returned to the baseline status. Second, vital signs should be stable and within acceptable limits. Third, the use of scoring systems may assist in documentation of fitness for discharge. Fourth, sufficient time (up to 2 hours) should have elapsed after the last administration of reversal agents (naloxone or flumazenil) to ensure that patients do not become resedated after reversal effects have worn off. Fifth, outpatients should be discharged in the presence of a responsible adult who will accompany them home and be able to report any postprocedural complications. Finally, outpatients and their escorts should be provided with written instructions regarding postprocedural diet, medications, activities, and a telephone number to be called in case of emergency. The ASA does not dictate which scoring systems should be used to assess patient fitness for discharge; the best known systems include the Aldrete [12] and modified Aldrete [13] scoring systems. Both use a 0 2 scale across five categories, for a maximal score of 10. The modified Aldrete system replaces clinical observation to assess the patient s oxygenation with pulse oximetry. The patient is considered fit for discharge with a total score of 9 or more [12, 13]. Other Considerations We think that the discussion of any guidelines is incomplete without acknowledging that The Joint Commission oversees all operations in accredited institutions [14]. The Joint Commission guidelines have at least four chapters on provision of care, treatment, and services that contain numerous standards that each institution must achieve, covering all aspects of procedures using moderate sedation, including credentialing of the opera- AJR:201, November

6 Olsen et al. tor and pre-, intra-, and postprocedural care of the patient. The informed observer will note that the summarized guidelines do not stray from the established practice standards. According to The Joint Commission [14], all procedures using moderate sedation must have the equipment and personnel available for the periprocedural monitoring of the patient, as well as equipment that may be required in resuscitation efforts. Also, the operator must be qualified and have the credentials to manage a patient at any level of sedation achieved, whether intentional or unintentional. The Joint Commission mandates the preprocedural assessment of the patient, by a practitioner qualified to administer sedation, within 48 hours of the procedure and immediately before the initiation of sedation. It is not specifically required that a common institutional form be used, but it may aid in documentation, which is also covered in other Joint Commission practice standards. The practice standard covering the intraoperative monitoring of patients is brief in relation to the others covered here; it specifically requires that the patient s oxygenation, ventilation, and circulation are monitored continuously. Similar to the preprocedural assessment, a postprocedural assessment must be conducted immediately after the procedure and documented within 48 hours. Before discharge, the patient s physiologic status, mental status, and pain level must be monitored. Specific attention is directed toward the allowance for adjusting the frequency and intensity of recovery monitoring in accordance with the potential effects of the procedure. This is of interest to the radiologist, because procedures conducted within the radiology department are, typically, of lesser risk than the operating room procedures also covered by the above practice guidelines [14]. It is at the discretion of the operator to initiate or cancel a procedure. As the operator, the radiologist will be responsible for any adverse outcomes that result from the use of sedation, even after the patient leaves the facility [15]. Alcohol or other drugs can interact with the commonly administered sedatives and analgesics to compound their effect and increase the risk of respiratory depression and desaturation [16]. The importance of a thorough preprocedural evaluation and strict adherence to discharge criteria, especially limitations on driving, cannot be overstated [15]. Also, many radiologic procedures use ionizing radiation, and the harm of such radiation to the developing fetus may be avoided in elective procedures. It is never too safe to obtain a recent β-hcg level before initiating a procedure on a female patient of reproductive age. It is important to know the pharmacology of the drugs being used, because the radiologist is responsible for all possible effects of the medications given, even after the patient has left the facility. Courts have decided in favor of injured patients when injury resulted from delayed effects of medications used during radiologic procedures [15]. Summary The number of radiologic procedures requiring moderate sedation is increasing, and there is anecdotal evidence of varied resident and fellow education on the topic of moderate sedation. The ACR-SIR and the ASA have published guidelines offering assistance to the radiologist on the use of moderate sedation. Opioids are used for analgesia and sedation, whereas benzodiazepines are used for sedation and for antegrade amnesia. Both are commonly used together for moderate sedation; knowledge of their pharmacology and effects, especially when used together, is extremely important for patient safety when administering moderate sedation. The radiologist is responsible for knowing the patient s medical history, medications, and any additional history that may increase risk during sedation. There are situations in which prior consultation with an anesthesiologist or critical care specialist is indicated. Be aware of commonly encountered complications and have a plan to correct the situation. Consider the possibility of consulting the anesthesiology department before beginning in high-risk situations or early if complications do arise. References 1. Bhargavan M, Sunshine J. Utilization of radiology services in the United States: levels and trends in modalities, regions, and populations. Radiology 2005; 234: American College of Radiology and Society of Interventional Radiology. ACR-SIR practice guideline for sedation/analgesia. American College of Radiology website. F194CBB800AB43048B997A75938AB482.pdf. Published Accessed June 14, American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 2002; 96: Mallampati SR, Gatt SP, Gugino LD, et al. 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