February 9, 2009
Sedation and Analgesia in MR Imaging
By Leonard Berlin, MD, FACR
Vol. 10 No. 3 P. 22
Editor’s Note: Leonard Berlin, MD, FACR, is a professor of radiology at Rush University Medical College and the chairman of the department of radiology at Rush North Shore Medical Center in Skokie, Ill. He began writing on risk management and malpractice issues in a series of articles in the American Journal of Roentgenology. Those articles became the basis for his well-known book Malpractice Issues in Radiology. This Risk Management & Malpractice Defense column is drawn from that book.
The third edition of Malpractice Issues in Radiology is scheduled for release early this year and will be available from the American Roentgen Ray Society.
After examining a 57-year-old man who was complaining of forgetfulness and other vague neurologic symptoms, the family physician suggested that the patient undergo MR imaging of the brain. The patient informed the physician that he was claustrophobic and anxious, and requested that he be given “something to calm me down.” In response, the physician gave the patient a prescription for two 2-mg tablets of lorazepam (Ativan; Wyeth Laboratories) with instructions that the patient take one tablet 20 minutes before the MR examination, and take a second tablet “if necessary.”
Three days later, the patient registered at an outpatient MR facility. The patient self-administered the lorazepam approximately 5 min before undergoing the MR study, which included IV injection of 15 mL of gadopentetate dimeglumine (Magnevist; Schering). The imaging procedure lasted approximately 1 hour, during which the patient mostly slept. At the conclusion of the study, the patient dressed and prepared to leave the facility. However, the MR technologist suggested that the patient “might want to wait an hour or so” and call a friend or relative to drive him home, particularly if the patient “felt groggy.” The patient left the facility 5 min later. The MR study was later interpreted as normal.
While driving home after leaving the MR facility, the patient crashed into a streetlamp pole. He was taken by ambulance to a nearby hospital emergency department, where a tear of the thoracic aorta was promptly diagnosed. The patient underwent immediate surgical repair and eventually recovered, although his total medical expenditures approximated $200,000 and he was unable to work for 8 months.
One month after returning to work, the patient filed a medical malpractice lawsuit against the family physician and the MR facility, claiming that his chest injuries resulted directly from the negligent conduct of the family physician for “oversedating” him and of the personnel in the MR facility for permitting him to drive his automobile while still under the effects of “sedating medication.” Attempts to settle the matter out of court were unsuccessful, and the lawsuit proceeded to a jury trial.
The trial began with the testimony of the plaintiff patient. The patient stated that he was told by the family physician to “take two tablets” of lorazepam “just before the MR exam.” The label on the bottle containing the tablets that had been prepared by a local pharmacy stated, “Take 1-2 tablets 20 minutes before MR.” The patient said that, in accordance with both the verbal and written instructions, he swallowed the two tablets shortly before undergoing the MR examination, and that he did indeed sleep through much of the study. He admitted that he “felt a little groggy” after the examination but denied that he had been told by anyone at the MR facility to either bring someone with him to drive him home or to wait at the facility after completion of the examination. The patient went on to say that he walked out of the facility, got into his automobile, and began the drive home. He concluded that he “remembered the beginning of the drive,” but that he “must have fallen asleep at the wheel” and could not remember the crash itself.
Malpractice Issues in Radiology
An expert in pharmaceuticals retained by the attorney for the plaintiff testified that the family physician had breached the standard of care by prescribing a 4-mg dose of lorazepam. The expert explained that lorazepam is an antianxiety agent that has a tranquilizing action on the central nervous system with no appreciable effect on the respiratory or cardiovascular systems, and that its peak concentration in the patient’s body occurs approximately 2 hours after oral administration. The pharmaceutical expert went on to say that, according to the Physicians’ Desk Reference, the usual total daily dose of the drug ranges from 2 to 6 mg and is ordinarily taken in two or three divided doses, a larger dose before bedtime. The pharmaceutical expert added that, for anxiety, most patients require a total initial daily dose of 2 to 3 mg, also given in two or three divided doses. According to the expert, a single 4-mg dose would be appropriate only for patients with insomnia, and then should be given only at bedtime. In the case of this particular patient, asserted the expert, a 4-mg dose would be considered an overdose and would indeed cause drowsiness, lethargy, and possible mental confusion.
The pharmaceutical expert was also extremely critical of personnel at the MR facility:
They should have known better; they should have known that a single 4-mg dose of lorazepam would have its peak effect 2 hours after the dose was taken, which meant that the maximum drowsiness would have occurred after the patient had left the MR facility. Those people should never have let the patient drive home.
During his testimony, the defendant family physician insisted that he had instructed the patient to take one 2-mg tablet of lorazepam, and a second tablet “only if necessary.” However, the physician admitted that he had not documented these instructions in writing.
Testifying in their own defense, the MR technologist and the administrator of the MR facility stated that when the original appointment was made, they told the patient to bring someone along to drive him home. They said that when the patient appeared without an accompanying driver, they attempted to convince the patient, after the examination was completed, that he should call someone to drive him home. During cross-examination of these personnel, the plaintiff’s attorney called attention to one of the facility’s written policies that stated that sedation, if required, should be taken by the patient 1 hour before commencement of the MR examination. In this case, however, there was only a 5-min period between the self-administration of medication and the MR study. “This was a blatant violation of your own policy,” charged the attorney for the plaintiff. The technologist and administrator each acknowledged that this was a “technical” violation of the facility’s policy, but they claimed that it made no difference whether the sedative was taken 5 minutes or 60 minutes before the MR examination.
In his closing argument to the jury, the attorney for the plaintiff contended that the defendant family physician was negligent because he prescribed an overdose of lorazepam, and personnel at the MR facility were negligent because they failed to prevent the patient from leaving the facility to drive home while still under the influence of sedating medication. The defense attorneys countered in their closing arguments that the main fault lay with the patient himself, who defied the instructions given to him by his doctor and the MR facility personnel. “The MR technologist and administrator are not policemen and cannot physically restrain a patient from leaving,” asserted one of the defense attorneys.
Before the jury was excused to deliberate the verdict, the judge instructed the jury that if it should decide that negligence had occurred and monetary damages should be awarded, the law in Illinois required the jury to apportion among the various participants in the lawsuit, including the plaintiff himself, the degree to which each party was negligent. The judge further explained that if the jury should rule that the patient was at least 51% negligent, he would receive no compensation whatsoever.
After deliberating for a day and a half, the jury ruled in favor of the plaintiff, awarding a total of $1.5 million in compensatory damages (Glaser v Costa, 2000). However, the jury further determined that the patient was responsible for 44% of the negligence; the MR facility, for 38%; and the family physician, 18%. As a result, the net award to the patient was reduced to $840,000, two thirds of which was borne by the insurance company for the MR center. The verdict was publicized by the local news media.
The term “sedation and analgesia” describes a clinical state that allows patients to tolerate unpleasant procedures while maintaining adequate cardiorespiratory function and the ability to respond purposefully to verbal command.1 This three-word term replaces the imprecise two-word term “conscious sedation.” The Joint Commission identifies four levels of sedation: minimum (anxiolysis); moderate (“conscious sedation”); deep; and anesthesia (general, spinal, or major regional).
Because sedation is used frequently in children undergoing diagnostic or therapeutic medical procedures and because of reports of deaths in children undergoing sedation, the American Academy of Pediatrics was first to draw the attention of the medical community to the need to improve the safety of sedation practices by issuing sedation guidelines in 1985. In 1993, The Joint Commission determined that the standard of care for patients who receive sedation should be uniform throughout an institution and began issuing standards that have been updated annually ever since. In 1995, the American Society of Anesthesiologists approved “Practice Guidelines for Sedation and Analgesia by Non-Anesthesiologists.” In the same year, the American College of Radiology (ACR) established guidelines for the safe administration and monitoring of IV conscious sedation. Three years later, the “ACR Standard for Pediatric Sedation/Analgesia” was issued.
Articles dealing with sedation practices were published in the radiology and nonradiology scientific literature in the mid 1980s and 1990s. A review of the literature conducted by Frush et al. that appeared in 1996 disclosed that virtually every article published to date dealt with patients in the pediatric age group.2 In an earlier article, Frush and Bisset pointed out that other earlier articles dealt primarily with the safety and effectiveness of sedating agents, whereas later ones dealt with monitoring and management of patients.3 The scientific literature and the guidelines on sedation promulgated by the professional organizations have paid scant attention to the issue highlighted in the malpractice lawsuit described here: When and under what circumstances is it safe to discharge an adult outpatient who has been administered a sedating drug? Notwithstanding the relative dearth of material relating to management of patients after sedation, some discharge guidelines germane to this lawsuit can be found and are worthy of our examination.
The American Society of Anesthesiologists’ “Practice Guidelines for Sedation and Analgesia by Non-Anesthesiologists” include the following under the section on “Guidelines for Discharge”:
Patients should be alert and oriented…. Vital signs should be stable and within acceptable limits…. Outpatients should be discharged in the presence of a responsible adult who will accompany them home….
The original 1995 version of the “ACR Standard for the Use of Intravenous Conscious Sedation” includes the following admonitions in the section entitled “Discharge Criteria”:
The patient should not be discharged until vital signs, level of consciousness, and motor function have returned to acceptable pre-procedure levels…. If discharge is to home … written discharge instruction should [warn that there be] … no driving or operating dangerous machinery for 24 hours.
A revision of this standard that became effective January 1, 2001, renamed the “ACR Standard for Adult Sedation/Analgesia,” modified this last admonition:
When discharge is to home, written discharge instructions… should include … advice against driving or operating dangerous machinery for a minimum of 12 hours.
It is interesting to note that the revision in the standard reduced the driving prohibition from 24 to “a minimum of” 12 hr and softened the radiologist’s duty relative to the driving prohibition from a definite “should” to an “advise against.” It should also be pointed out that the later version of the standard extends the applicability to oral as well as IV drugs and expands the definitions of the term “sedation/analgesia” into four categories, similar to those of The Joint Commission: light sedation or anxiolysis, defined as the administration of oral medications for the reduction of anxiety and a drug-induced state during which the patient responds normally to verbal commands; moderate or conscious sedation/analgesia in which there is a minimally depressed level of consciousness but the patient still retains continuous and independent ability to maintain protective reflexes and can be aroused by physical or verbal stimulation; deep sedation or analgesia in which there is a more depressed consciousness or unconsciousness from which the patient is not easily aroused; and general anesthesia in which there is a controlled state of unconsciousness during which the patient completely loses protective reflexes. In the clinical setting there is often an overlap of these categories. Indeed, in the case described in this article, the family physician may well have intended the patient to undergo light sedation or anxiolysis, but in fact the patient may have fallen into the moderate or even the deep states of sedation while driving home.
Bluemke and Breiter reviewed the cases of nearly 5,000 patients who between 1991 and 1998 received conscious sedation to undergo MR imaging at The Johns Hopkins Hospital.4 Their article pointed out another fact that is germane to the lawsuit under discussion—one that should be kept in mind by all radiologists who are in any way involved with sedating patients or monitoring patients who have been sedated. These researchers found that patients required a mean of 24.9 ± 17.7 min after the administration of the first medication to be sufficiently sedated to undergo MR imaging. The mean duration of sedation was 63.6 ± 27.0 min. The total procedure time from drug administration to the patient’s awakening was 88.6 ± 30.7 min. Bluemke and Breiter also found that 26.6% of patients required a second sedation medication dose because of either inadequate sedation with the first dose or a prolonged MR examination, and 2.6% received a third medication dose.
Although this article has focused only on sedation for patients undergoing MR examinations, sedation or analgesia is clearly used far more frequently in interventional radiologic procedures. Radiologists involved in these procedures can obtain guidance and valuable advice regarding the monitoring and management of patients who require sedation by consulting the guidelines and standards promulgated by the professional organizations and excellent review articles such as those written by Mueller et al. and Kennedy et al.5,6
Summary and Risk Management
Because of claustrophobia, anxiety, or other reasons, patients frequently require sedation to successfully complete MR examinations. Although it is well recognized that patients undergoing sedation can sustain central nervous system or cardiopulmonary complications that may in turn generate malpractice litigation, it is probably less recognized that such patients may sustain injury after being discharged from the facility in which the MR imaging was obtained. Most patients requiring sedation are children who are discharged under the care of a parent or adult guardian, but approximately 20% of sedated patients are adults.7 Adults who have received sedating medication can suffer serious injury after being discharged from an MR facility, especially if they are unaccompanied by a companion. Malpractice litigation arising from such injuries can involve not only the facility in which the MR imaging was obtained, but also the radiologist and referring physician.
Risk management in radiology can lessen the likelihood of incurring a medical malpractice lawsuit and maximize the chances of a successful defense if a suit is filed, while at the same time enhancing good patient care. These risk management pointers relative to sedation or analgesia in MR imaging will help radiologists meet all three objectives:
• Radiologists involved in MR imaging should consider having in place a written policy that covers the manner in which medication is administered to patients who require sedation or analgesia, and the manner in which they will be monitored and discharged. Once established, all provisions of the policy should be closely adhered to, because failure to follow even the letter of the written policy may jeopardize the successful defense of a malpractice lawsuit that involves a sedation or postsedation patient injury.
• Adult outpatients who indicate that sedation is required for MR examination should be informed that they will not have the capability of safely driving an automobile for a minimum of 12 hr after the time of sedation. These patients should be advised to have a person of driving age accompany them to the facility in which the MR imaging will be performed.
• Patients who require sedation and who appear for MR examination unaccompanied by a person of driving age present a dilemma. If no driver or taxicab is available to transport the patient home after discharge, the MR study may have to be either completed without sedation or rescheduled.
• MR facilities should consider posting a sign that informs patients that if they require sedation, they must have another person accompany them after completion of the MR examination and discharge from the facility.
• Radiologists can consider having patients who are being sedated sign a statement that they will not drive an automobile after discharge from the facility, but whether this would legally protect the radiologist or facility should an injury occur is problematic. A judge or jury could later determine that statements made or signed by a patient before receiving sedating medication may be coercive, and statements made or signed by a patient after receiving sedating medication may be unreliable.
• Radiologists practicing in any field of radiology that involves sedation or analgesia of patients should be aware of and adhere to all applicable ACR standards. Radiologists should be familiar with practice guidelines for sedation/analgesia issued by The Joint Commission, the American Society of Anesthesiologists, and, for radiologists who work with patients in the pediatric age group, the American Academy of Pediatrics.
— This article appeared in its original form in the American Journal of Roentgenology. It is reprinted here with permission of the American Roentgen Ray Society.
1. Practice guidelines for sedation and analgesia by non-anesthesiologists. A report by the American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Anesthesiology. 1996; 84(2):459-471.
2. Frush DP, Bisset GS III, Hall SC. Pediatric sedation in radiology: The practice of safe sleep. Am J Roentgen. 1996;167:1381-1387.
3. Frush DP, Bisset GS III. Sedation of children in radiology: Time to wake up. Am J Roetgen. 1995;165:913-914.
4. Bluemke DA, Breiter SN. Sedation procedures in MR imaging: Safety, effectiveness, and nursing effect on examinations. Radiology. 2000;216:645-652.
5. Mueller PR, Wittenberg KH, Kaufman JA, Lee MJ. Patterns of anesthesia and nursing care for interventional radiology procedures: A national survey of physician practices and preferences. Radiology. 1997;202:339-343.
6. Kennedy PT, Kelly IMG, Loan WC, Boyd CS. Conscious sedation and analgesia for routine aortofemoral arteriography: A prospective evaluation. Radiology. 2000;216:660-664.
7. Finn JP. Sedation in MR imaging: What price safety? Radiology. 2000;216:633-634.