An 84-year old woman presents to your ED with a traumatic, left-sided posterior hip dislocation. You need to reduce the hip. But how should you sedate her? Procedural sedation is an important component of ED care. It allows us to more comfortably perform otherwise painful procedures such as fracture or dislocation reductions, endoscopies, large laceration repairs, and I&Ds. How safe is procedural sedation in older adults?
Sedation for any patient requires preparation, airway assessment, and close monitoring. The physician has to be prepared in case of adverse medication reaction, respiratory depression, need for airway protection, and cardiovascular side effects of the medications. But is any other preparation needed for elderly patients (age 65 and over)? Are the commonly used medications safe? Are older patients at increased risk of side effects? Procedural sedation has been discussed in detail elsewhere (see EMcrit part 1 and 2 and EMBasic part 1 and 2). This discussion will focus specifically on the evidence in older patients. There are few studies on geriatric procedural sedation in the ED setting. However, we can also learn from studies in the anesthesiology and dental literature, as many older patients receive sedation for colonoscopies and dental work. Let’s look at a few agents that are commonly used.
Opioids and Benzodiazepines
This is a popular combination, and is generally tolerated well in older adults. There is a body of dental literature on sedation for the many older patients who undergo extractions and other dental procedures.
- In one study1 in which they gave sequential doses of diazepam and titrated it to clinical conscious sedation, they found that lower doses were required to reach the same level of sedation in older patients. Patients over 80 years old required 0.1 mg/kg diazepam, while those age 30-39 required over 2.5 mg/kg on average. Oxygen saturation declined slightly more in older patients, and this occurred within the first few minutes following administration of the medication.
- In another study with 200 patients (age 65 or over) undergoing brief dental procedures, there were no serious complications seen with fentanyl plus diazepam or midazolam. Midazolam was not available at the start of the study, but is preferred due to its shorter half-life. The mean fentanyl dose was 100 mcg, for diazepam was 9.2 mg, and for midazolam 3.9 mg. They also used small boluses of methohexital for amnesia, with a mean dose of 60.3 mg. They pretreated all patients with 100-500 mL of IV fluids, and patients had been NPO for solids for 8 hours, and clear liquids for at least 3 hours.2
- Comparing patients under 60 years old, who received 0.05 mg/kg of midazolam, with those over 60 years old who received 0.025 mg/kg midazolam for colonoscopy, even with the lower dose, the older patients experienced more frequent desaturation.3
This agent is also generally tolerated well in older adults, and is the preferred, first-line agent in many EDs. As with any patient, pay attention to the blood pressure, and an alternative agent may be preferable for those with hypotension.
- In an ED study4 of sedation with propofol +/- opioid or midazolam + opioid, they looked specifically at complication rates including hypotension, apnea, hypoxia, aspiration, need for rescue maneuvers, bradycardia, and death. There was no statistically significant difference in complication rates in patients age 18-49, 50-64, and ≥65, with rates of 5.2%, 5.4%, and 8%, respectively (p 0.563). However, the dose of sedative medications used decreased with both age and ASA score.
- For patients receiving propofol alone in another ED study, older patients required a lower dose. There were three age groups: 18-40, 41-64, and ≥65 years. The median induction doses were 1.4 mg/kg, 1 mg/kg, and 0.9 mg/kg, and the median total doses required were 2 mg/kg, 1.7 mg/kg, and 1.2 mg/kg.5
- Finally, a study that included patients up to age 60 noted that those who were 50-60 years old experienced airway complications more frequently than younger patients. Airway complications such as obstruction, desaturation, or hypoventilation requiring an intervention (stimulation, chin-lift, bag-valve mask, or OPA) occurred at a rate of 31% in the 50-60 year age-group, compared with 21% overall. There were more airway events if the level of sedation was deep (odds ratio doubled for a sedation level of 6 compared with sedation level 4). Airway events were more common in patients who had received propofol, midazolam, or fentanyl. However, the interventions were relatively minor, and no patients required intubation during the procedure (one patient aspirated and was intubated later).6
While ketamine has become a favorite agent in many EDs and has been used successfully in children for many years, it is probably NOT the best first choice in certain older adults.
- There are a number of older, small studies of ketamine used as the sole agent in the OR to perform open reduction and intern fixations of hip fractures in older adults.7 In a study with an average patient age of 83 years, during ketamine administration, patients experienced increased blood pressure and cardiac index, but there were no serious adverse events.8 Another small study compared ketamine and propofol as the sole agents during hip fracture repair in the OR, and found that ketamine increased myocardial oxygen demand.9
- In general, there is a higher prevalence of hypertension and coronary artery disease among older patients. Increasing the myocardial oxygen demand could present a risk with ketamine use. However, there is little evidence one way or the other (if you find good papers with adequate numbers of older patients, please post in the comments!) Ketofol may be good option (combination propofol and ketamine), but the recent studies of ketofol in the ED enrolled few older patients. 10,11
Etomidate is not as often used as a first-line agent. It has the unpleasant side effect of myoclonus. However, it is otherwise generally well-tolerated in older adults, and is still a common first-line medication for intubation.
- In a small, retrospective comparison of older and younger adults who received etomidate for procedural sedation, there was no statistically significant difference between the complication rate in older (20%) and younger (14.8%) adults, and their rates of complication were similar to prior studies.12 The average etomidate dose was 0.14 mg/kg for the younger and older adults. Most patients received an opioid and/or low dose benzodiazepine in addition. Of the 45 elderly patients included in their study, 3 had emesis without aspiration, 2 suffered hypoxia that resolved within 5 minutes with supplemental oxygen, 1 had bradycardia that resolved, 3 had asymptomatic hypertension, and one had fasciculations.
THE BOTTOM LINE
- Procedural sedation is generally safe in older adults. What’s not acceptable is under-treating pain or inadequately sedating a stable patient.
- You should take all the usual precautions, and consider any co-morbidities that could make the patient more at risk of adverse reactions or complications, more difficult to bag or intubate, or more at risk of decompensation from limited physiologic reserve.
- Older patients usually require lower doses of medications. They tend to be more sensitive to medications, with slower metabolism, less physiologic reserve to handle side effects, and a smaller volume of distribution.
- Older patients may be at higher risk for oxygen desaturation, but they usually responds quickly to supplemental oxygen.
Expert Peer Reviewer
In this ALiEM post, Christina examines pharmacologic approaches and outcomes for procedural sedation in older adults. Christina does a great job of summarizing the existing literature on the subject, and I agree with her interpretation: procedural sedation is generally safe in older adults; older adults usually require lower doses of medications; and supplemental oxygen is a good thing.
Having seen a procedural sedation go wrong, I would add the following perspective. Studies of outcomes during procedural sedation with 200 patients are informative, but don’t tell us much about rates of very rare events. Most of the events reported in these studies (e.g. transient hypoxia, emesis, bradycardia, etc.) portend a risk for a more serious event but in themselves are not significant. However, serious adverse outcomes including death from procedural sedation in otherwise healthy patients do occur. From the perspective of the patient and the patient’s family, such events are disasters not different than a plane crash. As providers, our responsibility is to make these never events. (They are in fact listed as never events by the National Quality Forum.) So, the question we face is not “what’s generally safe?” but rather “what approach to procedural sedation will ensure that we never have a bad outcome?”
In this light, I think ketamine looks quite good. Ketamine doesn’t cause clinically significant respiratory depression, which is the main cause of deaths in patients receiving procedural sedation. In addition, ketamine is a powerful analgesic, and co-administration of benzodiazepines can decrease the risk of dysphoria. Increased blood pressure and myocardial oxygen demand would be a concern if linked to cardiac events, but this link has not been established.
From the ‘never event’ perspective, propofol looks okay. Propofol is a very strong anesthetic which can cause profound respiratory depression and apnea, but it is also very short acting. If you assign a person to monitor and treat oxygen desaturation when your patient is receiving propofol, then you can protect the patient. Propofol is not a very potent analgesic so supplementation with opioids is sometimes required.
The approach that concerns me the most is opioids and benzodiazepines. Because these medications have longer half-lives, the time period over which the patient might have a serious adverse event is quite long. Both medications are also fat soluble, which means that individuals with high relative body fat, which characterizes most older adults, can have a fairly slow release of the medication back into the blood. A patient who completed their procedural sedation two hours ago and is no longer being monitored might still be exposed to high drug levels. One unique advantage of opioids and benzodiazepines are that reversal agents are available for these medications, but this is obviously not helpful for a patient who is no longer in the ED.
In the future, dexmedetomidine, an alpha agonist which causes sedation without respiratory depression, may be useful for procedural sedation.
Of course, theoretical speculations about risk only get you so far. More data on outcomes for older adults receiving procedural sedation are needed.