Emergency physicians provide acute care for an extraordinarily broad range of illnesses and injuries, the majority of which involves some degree of pain. Emergency providers also cause pain in the course of therapeutic and diagnostic procedures. This chapter considers the prevalence of pain in the emergency department (ED), barriers to its adequate treatment, and a variety of treatment modalities. Space limitations prohibit a discussion of the wide variety of specific painful conditions that present to the ED. These can be found in other chapters of the text.
Prevalence and Assessment of Pain in the Emergency Department
The prevalence of pain among emergency department (ED) patients is as high as 78%, and among those with pain, underlying chronic pain conditions are present in 40%. A national survey suggests that 24 million adults with chronic pain visit the ED annually and that 12 million visits are due to exacerbations of chronic pain syndromes. Although arriving at a diagnosis and choosing the appropriate therapy to treat underlying conditions are principal goals for physicians, those who present to the ED with pain also desire recognition of their pain and rapid, effective pain treatment.
Patients face many barriers in their efforts to obtain superior medical care, especially in regard to pain. The ED serves as a fail-safe mechanism for our fragmented health care system, and pain is but one of the many conditions in which we not only face the problem of acute clinical presentations but also care for those with chronic pain who are seeking access to specialized pain care.
Notwithstanding the issue of providing compassionate care, pain that is not acknowledged and managed appropriately causes anxiety, depression, sleep disturbances, increased oxygen demands with the potential for end-organ ischemia, and decreased movement with an increased risk of venous thrombosis. Failure to recognize and treat pain may also result in dissatisfaction with medical care, hostility toward the physician, unscheduled returns to the ED, delayed complete return to full function, and an increased risk of litigation.
Pain is inherently subjective and inevitably complex. Our patients experience pain and suffering as individuals; we assess it only indirectly. The ED’s task is to use a commonly understood vocabulary and classification system in assessing pain so that our findings can be communicated consistently. Only by quantifying the pain experience in meaningful ways can we move beyond myth and opinion toward a scientific approach to our many questions regarding the pain experience. This challenge is at the root of our difficulties in treating pain; thus issues surrounding pain assessment have primacy in our approach to understanding. Only when we use comparable methods in assessing pain can we begin to accumulate the scientific evidence that should drive our practice.
The most common response of physicians confronted by patient pain reports is skepticism. The validity of patient self-reports is often questioned, and attempts to “objectify” the pain experience are sought. This search is bound to disappoint the querulous clinician, as neither blood tests, tissue pathology, diagnostic imaging, physical assessments, nor patient behavior reliably reflects the internal pain experience.
A number of practical pain assessment tools are available. The subjective nature of pain makes such instruments necessary, and revised standards of The Joint Commission (TJC) have fostered their widespread use. Pain intensity should be assessed for all patients presenting to the ED with either an 11-point numeric rating scale (NRS) or a graphic rating scale (GRS). The NRS is sensitive to the short-term changes in pain intensity associated with emergency care. The GRS or picture scales are particularly useful for populations with limited literacy, including children. In one study of patients who have advanced cancer and pain, 81% were able to complete a picture scale, whereas only 75% could complete the visual analog scale. In another study, the authors noted that male patients were uncomfortable with scales depicting severe pain using tears. Picture scales with such depictions might profitably be avoided because they may be biased in the direction of less severe pain in male patients. No matter the specific pain scale used, assessments should be repeated after therapeutic interventions and at the time of ED discharge.
The Problem of Emergency Department Oligoanalgesia
Although adequate analgesia in the ED is an important goal of treatment, the underuse of analgesics, termed “oligoanalgesia” by Wilson and Pendleton in 1989, occurs in a significant proportion of ED patients. A variety of factors are felt to give provenance to pain undertreatment ( Box 75.1 ).
- 1.
Lack of educational emphasis on pain management
- 2.
Inadequate emergency department (ED) quality improvement systems
- 3.
Lack of ED pain research, particularly among older adult and pediatric populations
- 4.
Emergency providers’ concerns regarding opioid addiction and abuse
- 5.
Fear of opioid adverse effects
- 6.
Racial and ethnic bias
Recognized risk factors for ED oligoanalgesia include extremes of age and minority ethnicity. It has been suggested that patients’ expectations for pain treatment and perceptions of pain intensity do not differ by ethnic groups when patients are matched for socioeconomic factors. Differences have been noted, however, in the way that patients of different cultural backgrounds express their pain. Differences in the interactions of physicians and patients of a different ethnic group have been described and may affect physician assessment. When affect, actual patient-physician interaction, and cultural expressions of ethnicity are removed from a case presentation, such as with written clinical vignettes, patients with similar pain are similarly treated by physicians. Cultural discordance between the patient and the physician may hinder the ability of patients to confer an understanding of their pain to their physician.
Although there is a general reluctance to accept patient report as the most reliable indicator of pain and disparities between patients’ and physician’s pain intensity ratings may lead to inadequately treated pain, patients themselves may be reluctant to report pain presence and intensity. This may be a result of low expectations of obtaining pain relief, fear of analgesic side effects, and a notion that pain is to be expected as part of the underlying disease or from medical treatments. Some patients have a fear of addiction when prescribed opioids or fear the stigma associated with opioid use.
Although patients may decline opioid analgesics due to concerns about addiction, the emergency department may also be targeted by patients seeking controlled substance for misuse or diversion. Unfortunately, prescription opioid abuse is a continuing concern in the U.S. population. The National Survey on Drug Use and Health estimates that among those aged 26 or older, 3.2 % reported using pain relievers nonmedically within the past 12 months. It is encouraging that the misuse of pain relievers by youth and young adults appears to be in decline. Among youths aged 12 to 17, nonmedical pain reliever use fell from 3.2% to 2.3% between 2002 and 2011, and among young adults aged 18 to 25, rates have fallen to 3.6% from a high of 5.0% in 2006.
Although pain is far more common than substance abuse, emergency physicians frequently encounter both among patients. Professional discussions of pain in the ED often center on concerns of being duped by patients who fabricate symptoms to obtain opioids, so-called drug-seeking behavior. Complicating this issue, such behaviors may represent an appropriate response by those with untreated chronic pain for whom treatment resources are lacking. In managing pain complaints, emergency physicians are responsible for beneficence and nonmaleficence. They must treat pain and ameliorate suffering while minimizing the extent to which their decisions enable substance abuse by patients and increase the supply of prescription opioids available for abuse by the general public. The increasing functionality of online prescription monitoring programs is a promising development that can aid emergency physicians in differentiating appropriate and problematic requests for opioid analgesics.
The Problem of Emergency Department Oligoanalgesia
Although adequate analgesia in the ED is an important goal of treatment, the underuse of analgesics, termed “oligoanalgesia” by Wilson and Pendleton in 1989, occurs in a significant proportion of ED patients. A variety of factors are felt to give provenance to pain undertreatment ( Box 75.1 ).
- 1.
Lack of educational emphasis on pain management
- 2.
Inadequate emergency department (ED) quality improvement systems
- 3.
Lack of ED pain research, particularly among older adult and pediatric populations
- 4.
Emergency providers’ concerns regarding opioid addiction and abuse
- 5.
Fear of opioid adverse effects
- 6.
Racial and ethnic bias
Recognized risk factors for ED oligoanalgesia include extremes of age and minority ethnicity. It has been suggested that patients’ expectations for pain treatment and perceptions of pain intensity do not differ by ethnic groups when patients are matched for socioeconomic factors. Differences have been noted, however, in the way that patients of different cultural backgrounds express their pain. Differences in the interactions of physicians and patients of a different ethnic group have been described and may affect physician assessment. When affect, actual patient-physician interaction, and cultural expressions of ethnicity are removed from a case presentation, such as with written clinical vignettes, patients with similar pain are similarly treated by physicians. Cultural discordance between the patient and the physician may hinder the ability of patients to confer an understanding of their pain to their physician.
Although there is a general reluctance to accept patient report as the most reliable indicator of pain and disparities between patients’ and physician’s pain intensity ratings may lead to inadequately treated pain, patients themselves may be reluctant to report pain presence and intensity. This may be a result of low expectations of obtaining pain relief, fear of analgesic side effects, and a notion that pain is to be expected as part of the underlying disease or from medical treatments. Some patients have a fear of addiction when prescribed opioids or fear the stigma associated with opioid use.
Although patients may decline opioid analgesics due to concerns about addiction, the emergency department may also be targeted by patients seeking controlled substance for misuse or diversion. Unfortunately, prescription opioid abuse is a continuing concern in the U.S. population. The National Survey on Drug Use and Health estimates that among those aged 26 or older, 3.2 % reported using pain relievers nonmedically within the past 12 months. It is encouraging that the misuse of pain relievers by youth and young adults appears to be in decline. Among youths aged 12 to 17, nonmedical pain reliever use fell from 3.2% to 2.3% between 2002 and 2011, and among young adults aged 18 to 25, rates have fallen to 3.6% from a high of 5.0% in 2006.
Although pain is far more common than substance abuse, emergency physicians frequently encounter both among patients. Professional discussions of pain in the ED often center on concerns of being duped by patients who fabricate symptoms to obtain opioids, so-called drug-seeking behavior. Complicating this issue, such behaviors may represent an appropriate response by those with untreated chronic pain for whom treatment resources are lacking. In managing pain complaints, emergency physicians are responsible for beneficence and nonmaleficence. They must treat pain and ameliorate suffering while minimizing the extent to which their decisions enable substance abuse by patients and increase the supply of prescription opioids available for abuse by the general public. The increasing functionality of online prescription monitoring programs is a promising development that can aid emergency physicians in differentiating appropriate and problematic requests for opioid analgesics.
Pain Treatment and Procedural Sedation
Effective pain management involves both pharmacologic and nonpharmacologic modalities. Simply asking about pain and validating the pain reports has a potent effect on patients’ satisfaction with ED pain management. In one study, patient satisfaction with pain management was predicted more strongly by the perception that ED staff asked about pain than by the actual administration of an analgesic. Other modalities such as reassuring the patient that pain will be addressed, immobilizing and elevating injured extremities, and providing quiet, darkened rooms for patients with migraine headaches are essential aspects of quality pain management.
Pharmacologic therapies should begin as soon as is practical after presentation to the ED. Analgesic protocols allowing early pain treatment can decrease the time to effective treatment and improve patient outcomes. Analgesics may be administered by a variety of routes; however, the majority of medications are administered by the oral or parenteral routes. Oral therapies are most commonly used because they are convenient and inexpensive for patients who can tolerate oral intake. When pain is severe, analgesics must be given immediately and titrated to effect. The intravenous rather than intramuscular (IM) route is indicated in this context. IM injections are painful, they do not allow for titration, absorption is unpredictable, and they result in slow onset of drug action. Unless intravenous access is elusive, there is little to recommend the IM route.
In general, it is inappropriate to delay analgesic use until a diagnosis has been made. In the case of acute abdominal pain, a large number of studies find no deleterious effect of intravenous opioid therapy on our ability to make appropriate diagnoses.
Specific Treatment Modalities
A wide variety of analgesics are used in emergency medicine practice. In a 20-site survey of ED analgesic practice, a total of 735 doses of 24 different analgesics were administered to 506 patients receiving analgesics while in the ED. The majority of analgesics administered were opioids (59%), morphine being the most commonly used analgesic (20%), followed by ibuprofen (17%). Analgesics recorded as being administered in the report are listed in Table 75.1 .
| Medication | N (%) |
| Morphine | 148 (20.1) |
| Ibuprofen | 127 (17.3) |
| Hydrocodone/acetaminophen | 93 (12.7) |
| Oxycodone/acetaminophen | 83 (11.3) |
| Ketorolac | 60 (8.2) |
| Acetaminophen | 53 (7.2) |
| Hydromorphone | 36 (4.9) |
| Antacid | 26 (3.5) |
| Meperidine | 24 (3.3) |
| Fentanyl | 23 (3.1) |
| Metoclopramide | 13 (1.8) |
| Codeine/acetaminophen | 12 (1.6) |
| Oxycodone | 10 (1.4) |
| Naproxen | 9 (1.2) |
| Other | 18 (2.4) |
| Total | 735 (100) |
Nonopioids
Commonly available analgesics include opioid and nonopioid agents. When opioids are required for pain treatment, nonopioids should be included to potentiate the opioid analgesic effect and decrease the severity of side effects. Nonopioids include salicylates, nonsteroidal anti-inflammatory drugs (NSAIDs), and acetaminophen. Unfortunately, nonopioid agents exhibit an analgesic ceiling effect and cannot be titrated to effect. This limits their usefulness in the setting of severe or fluctuating pain; however, they should be used as an adjunct to opioid therapies unless contraindicated, for the reasons noted earlier.
Acetaminophen is indicated for mild to moderate pain and is often combined with opioid agents. Acetaminophen, unlike NSAIDs, has no antiplatelet activity or anti-inflammatory effect. Although a great deal of attention has been paid to acetaminophen hepatotoxicity, especially in the setting of chronic malnutrition, alcoholism, or liver disease, such effects are uncommon, particularly as compared to NSAID-related gastrointestinal toxicity.
NSAIDs, including salicylates, inhibit prostaglandin synthesis by interfering with cyclooxygenase (COX) enzymes. They cause platelet dysfunction and can precipitate renal failure in patients with renal insufficiency or volume depletion. They increase the risk of gastrointestinal bleeding when taken chronically.
Opioids
Opioid combination analgesics are commonly used for moderate to severe pain. Although the opioid component in these agents does not exhibit ceiling analgesic effects, the nonopioid component dose must be limited; thus, one cannot titrate these analgesics. The convenience of combination therapy must be balanced against this limitation. Hydrocodone and oxycodone combination agents are associated with less nausea and vomiting and are preferable to codeine combination agents. Also a significant proportion of the population is made up of poor metabolizers of codeine, which must be metabolized to morphine in order to manifest analgesic effects, further limiting its effectiveness.
The tramadol-acetaminophen combination agent is indicated for acute pain; however, experience with this agent in the ED setting is limited. Its mechanism of action is unclear: the tramadol component binds only weakly to opioid receptors and inhibits the reuptake of both norepinephrine and serotonin.
Opioids are the mainstay of ED therapy for moderate to severe pain, and morphine is the standard of comparison for all agents of this class. If contraindicated because of allergy or other sensitivity, hydromorphone or fentanyl may be substituted. These opioids can be rapidly titrated intravenously to control severe pain, allowing institution of an oral regimen. Fentanyl has the advantage of being relatively short acting and is preferred in the setting of multiple trauma, head injury, and potential hemodynamic instability. Intravenous morphine is the standard of treatment for severe pain in the ED. Morphine 0.1 mg/kg bolus has been found to be safe but not usually adequate to effect pain relief. Repeat boluses of 0.05 mg/kg every 5 minutes until pain relief represents a safe incremental strategy.
Meperidine is a problematic opioid for a number of reasons. Many EDs have completely eliminated the use of meperidine because of its metabolism to normeperidine, a toxic metabolite causing central excitation and seizures, as well as its contraindication in patients taking monoamine oxidase inhibitors. It is, however, frequently used. In a review of ED patients treated in the United States for isolated benign headache, meperidine was found to be the most common prescribed treatment, despite national recommendations for the use of nonopioid therapies supported by strong evidence. This likely has more to do with the persistence of medical tradition than with pharmacology. Subtherapeutic doses of intramuscularly administered meperidine have been used to treat a wide variety of acute pain complaints by generations of physicians. The availability of other opioid agents of equal efficacy with fewer contraindications and fewer adverse effects argues against its continued use.
Agonist-antagonist opioids, such as nalbuphine and butorphanol, have mixed effects on opioid receptor subtypes, exhibiting ceiling effects on both analgesia and respiratory depression. Because clinically important respiratory depression is distinctly rare in the setting of acute pain treatment, it is difficult to justify their routine use. One possible exception is for patients with advanced pulmonary disease. In particular, one cannot titrate these drugs to maximal effect because of analgesic ceiling effects. Additionally, these drugs are contraindicated and will induce withdrawal symptoms in patients who are physically dependent on opioids, either because of opioid therapy for chronic pain, methadone maintenance therapy, or active opioid addiction.
Patient-Controlled Analgesia
The use of patient-controlled analgesia (PCA) has been described in emergency medicine in adults and children. Although no specific advantage has been found over the titration of opioids, PCAs were found to be at least as effective. In the setting of high demands on nursing resources, PCAs could serve to ensure pain treatment.
Alternative Delivery Routes
Multiple alternative delivery routes for the administration of pain medications have been described. The use of nebulized fentanyl has been described and holds great promise as a route of opioid delivery that can be initiated before an intravenous (IV) needle has been placed. Intranasal fentanyl has also been described and shown to be effective in the ED and the prehospital setting. The promise of nebulized and intranasal pain medications, especially in children who have severe pain but have not had an IV needle placed yet, could be very useful in the ED.
Procedural Sedation and Analgesia
Minimal, moderate, and deep sedation have all been described in the ED. Patients often present to the ED in need of painful or complex procedures that require compliance that must be done emergently, and procedural sedation and analgesia (PSA) has adopted a specialized format for procedures in the ED. Unlike most patients who are undergoing sedation in other settings, patients in the ED have unpredictable nothing by mouth (NPO) status, often have concurrent severe systemic disease, and usually are in severe pain before the procedure begins. In addition, unpredictable concurrent events and time or bed constraints in the ED complicate these procedures.
The indications for ED PSA range from pain control for short painful procedures to the need for patient compliance with a complex emergent procedure. Goals for level of sedation during ED PSA range from minimal through moderate and deep sedation, depending on the needs for the procedure. Although it is acknowledged that deep sedation can inadvertently result in patients achieving a level of sedation consistent with anesthesia, this is not typically the goal of ED PSA. Minimal sedation, a drug-induced state during which patients respond appropriately to their developmental age to verbal commands, is generally performed for procedures that require compliance but are not typically painful with the use of local anesthesia. Minimal sedation has been described for lumbar puncture, evidentiary examinations, simple fracture reductions (in combination with local anesthesia), and abscess incision and drainage.
During minimal sedation, cardiovascular and ventilatory functions are usually maintained, although patients should be monitored for inadvertent oversedation to deeper levels with oxygen saturation monitors and close nursing supervision. Agents typical of minimal sedation include fentanyl, midazolam, combinations of the two, and low-dose ketamine.
Moderate sedation is performed on patients who would benefit from either a deeper level of sedation to augment the procedure or from amnesia of the event. Moderate sedation is a drug-induced depression of consciousness during which patients respond appropriately to their developmental age to verbal commands, either alone or with light tactile stimulation. Patients usually have an intact airway and maintain ventilatory function without support. As with minimal sedation, inadvertent oversedation to deeper levels can occur with moderate sedation; appropriate monitoring, including that for oxygen saturation as well as for cardiac and blood pressure, should be done throughout the sedation, and direct observation of the patient’s airway should be maintained throughout the procedure. Agents used for moderate sedation in the ED include propofol, etomidate, ketamine, and the combination of fentanyl and midazolam.
Deep sedation is performed on patients who would benefit from a deeper level of sedation in order to complete the procedure for which they were being sedated. Generally, amnesia of the procedure is similar between moderate and deep sedation, and it is not necessary to sedate patients to a deep level only to obtain amnesia of the procedure. Deep sedation generally is achieved in the ED with the same agents as moderate sedation; the difference is in the intended level of sedation. Monitoring for deep sedation is the same as for moderate with oxygen saturation, cardiac and blood pressure monitoring, and direct observation of the airway. End-tidal carbon dioxide has also been described in ED PSA, but its use over direct observation of the patient’s airway has not been established. Deeply sedated patients can develop respiratory depression but generally maintain a patent airway and adequate ventilation. Patients sedated to this level can progress to a level of sedation consistent with anesthesia, and there is some evidence that this may occur more frequently in patients intended to undergo deep sedation than in those who are to undergo moderate sedation. For this reason, it is usually safer to use moderate than deep sedation in the ED unless the procedure for which the patient was being sedated requires a deeper level of sedation (such as hip reduction).
Patients who progress to an unintended level of sedation consistent with anesthesia are not arousable, even to pain. The ability to independently maintain ventilatory function is usually impaired, and patients often require assistance in maintaining a patent airway. Because patients can quickly progress to this level using the agents typical of moderate and deep sedation, physicians performing moderate and deep sedation must be prepared to provide ventilatory support until the patient has regained consciousness. To decrease the likelihood of aspiration, patients who are undergoing moderate or deep sedation in the ED should be kept NPO. It is difficult to find a consensus on the amount of time a patient should be kept NPO prior to PSA. Many departments use 3 to 6 hours as a minimum. The risk of aspiration must be balanced with the urgency of the procedure, and it is often necessary to perform sedation on patients who have recently eaten when they have an emergent requirement for sedation. In general, the least deep level of sedation possible to complete the procedure should be used in patients who have not been NPO. ED PSA has been described in patients who are medically stable (American Society of Anesthesiologists Physical classes 1 and 2) and in those who are not (classes 3 and 4). PSA for critically ill children has been described using ketamine and in adults using propofol or etomidate. The degree of respiratory depression noted in these patients was similar to that for patients with physical status scores of 1 or 2, but an increased rate of hypotension was seen in physical status 3 and 4 patients who received propofol. It may be that ketamine and etomidate are better suited for the emergent sedation of critically ill patients, but data are not yet sufficient to make a definite recommendation.
Sedated patients are generally monitored by pulse oximetry, which is a sensitive measure of oxygenation. If a patient receives supplemental oxygen before starting PSA, this monitor may not be as sensitive to changes in the patient’s ventilatory status. Preoxygenation is generally recommended for ED PSA; however, there is no evidence that it decreases the incidence of transient hypoxia that has been noted as a complication of PSA. End-tidal carbon dioxide has been recommended as an additional modality for the monitoring of sedated patients. Monitoring expired carbon dioxide during PSA allows for a graphic display of the patient’s ventilatory status that can be a detector of respiratory depression before it becomes clinically apparent. In the event of hypoventilation, the end-tidal CO 2 value increases as the respiratory rate decreases. In the event of increasing airway obstruction, the baseline end-tidal CO 2 value decreases along with a blunting of the waveform as a result of increased mixing of the nasal expiratory sample with ambient air caused by the turbulence from the obstruction.
Ketamine has been described in adults but predominantly in children for use in ED PSA. It is a dissociative anesthetic that provides 15 to 20 minutes of sedation when given intramuscularly, with a return to baseline mental status in 30 to 60 minutes. It can be given in doses of 1 to 4 mg/kg IM and should be combined with atropine 0.01 mg/kg to prevent hypersalivation. The addition of 0.1 mg/kg of midazolam to ketamine has been described to prevent emergence phenomena, but this has been shown to have unclear use. The 1-mg/kg dose achieves light sedation sufficient for such procedures as lumbar puncture, dressing changes, and simple laceration repair. The doses ranging from 2 to 4 mg/kg result in increasingly deep levels of sedation but have all been shown to generally achieve moderate or deep sedation with a decreasing responsiveness to pain as the dose is increased. Patients sedated with ketamine usually maintain a patent airway and ventilate normally. Laryngospasm has been described with its administration at a fairly rare rate. Patients undergoing PSA with ketamine should be monitored for respiratory depression and possible laryngospasm. Emergence phenomena, described as an unpleasant perceptual experience by patients as they regain consciousness from sedation with ketamine, have been described in adults and children. The use of ketamine IV has also been described for ED PSA. It is generally given at 1 mg/kg IV and has an onset of 1 to 2 minutes, followed by moderate sedation lasting 8 to 12 minutes. The side effects have been described as similar to IM ketamine, and similar precautions should be taken. The combination of ketamine with propofol has also been described, with the theoretical advantage of decreased respiratory depression from propofol alone and decreased vomiting and emergence phenomena over ketamine alone. Several case studies and small trials have shown this combination to be generally safe and efficacious, but data are not sufficient to determine if there are situations in which the combination is superior to propofol for ketamine alone.
The combination of fentanyl and midazolam has been described for minimal, moderate, and deep sedation in the ED. These medications result in the longest sedation of the agents described here and have been noted to have a high rate of respiratory depression that increases with the dose. For this reason, this combination of agents, whereas adequate for minimal sedation, is less useful for moderate and deep sedation, and its use for these levels of sedation is not recommended. Dosing for minimal sedation has been described as 0.1 mg/kg IV midazolam followed by 0.5 µg/kg IV fentanyl, with repeated fentanyl boluses every 3 minutes until the patient is adequately sedated. The sedation typically lasts 30 to 60 minutes, with a return to baseline mental status of 45 to 120 minutes. This method of PSA has increasing respiratory depression with increasing levels of sedation, and close respiratory monitoring is required. A sedation regimen similar in duration but without analgesic properties is pentobarbital. It is usually used to sedate children for radiologic procedures. The medication is usually started at 2.5 mg/kg IV, followed by 1.25 mg/kg IV every 5 minutes until sedation is achieved. This is usually used for minimal or moderate sedation, and pulse oximetry is required. The rate of respiratory depression is lower than for other protocols but the sedation is inadequate for painful procedures.
Methohexital has also been described for moderate and deep PSA. It is a very short-acting agent with dense amnestic capabilities. It can be given at 1 mg/kg IV with 0.5-mg/kg repeat boluses every 2 minutes as needed. It has an onset of 30 seconds. The sedation generally lasts 2 to 4 minutes with a return to baseline mental status of 10 to 15 minutes. It has been associated with respiratory depression and a quick progression to deeper levels of sedation than intended, and it can result in oversedation even when carefully titrated. This agent therefore requires close respiratory monitoring throughout the sedation, as with other agents. When compared directly with propofol, it was found to be similarly effective and safe when only a single bolus was given and less safe than propofol when multiple doses were required. It therefore should be used principally for very brief procedures that are expected to last less than 2 to 4 minutes, such as simple fracture and dislocation reductions.
Propofol is well described for ED PSA. It is generally administered as a 1-mg/kg bolus with repeat boluses of 0.5 mg/kg every 3 minutes until the patient is adequately sedated for the procedure. The sedation persists 2 to 5 minutes after a single bolus and longer for patients receiving multiple boluses, with a return to baseline mental status in 10 to 15 minutes. This medication has been associated with rates of clinically apparent respiratory depression from 4% to 7.7% in ED PSA, so close respiratory monitoring is required as with the other agents. It has also been associated with hypotension in critically ill patients and should be used with caution in this group.
Another agent used in ED PSA is etomidate. It is usually given as a single bolus of 0.1 to 0.3 mg/kg, with an onset of sedation in 30 to 60 seconds and sedation lasting 7 to 10 minutes. It is not associated with hypotension and is therefore optimal in patients who are at risk for this condition. It is, however, associated with myoclonic jerking in up to 25% of patients receiving the medication, which can sometimes complicate the procedure for which the patient has been sedated. This makes it slightly suboptimal relative to propofol in healthy patients. Etomidate has been associated with adrenal suppression. This has been noted in studies of single boluses of 0.3 mg/kg, but no significant changes in cortisol levels were found, and the significance of this outcome remains unclear.
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