Minimal
Patient responds appropriately to normal-volume verbal cues, through voice or action. The response is immediate
Moderate
Patient responds purposefully to verbal or light tactile stimulus. The response is either verbal or physical, for example, opening eyes, turning head in a given direction, appropriate change in position
Deep
The patient does not respond to either verbal or tactile stimulus, but responds appropriately to painful stimuli
Minimal sedation or anxiolysis refers to a controlled state of diminished consciousness wherein the ability to respond to moderate verbal stimuli and the ability to maintain a patent airway are retained. There is little impact on the cardiopulmonary status. Although this is popularly referred to as conscious sedation by many nonanesthesia specialties, an ASA task force on this practice recommends the use of sedation and analgesia rather than conscious sedation [2].
Moderate sedation or analgesia is a drug-induced state during which a patient may be less responsive than with anxiolysis but still respond to verbal commands appropriately, although sometimes requiring simultaneous light tactile stimulation. Spontaneous respiration is maintained and cardiovascular parameters are unchanged.
Deep sedation or analgesia is a drug-induced condition whereby the patient may be difficult to awaken but will respond purposefully to painful stimuli. With deep sedation, spontaneous respiration may not be adequate, and the patient may not be able to maintain a patent airway without assistance. Although controversial, in general, the ASA and many hospitals recommend the presence of anesthesia-trained personnel if deep sedation is anticipated or required to complete a procedure [2]. At a minimum, deep sedation requires the immediate availability of an individual trained in cardiopulmonary resuscitation and airway management.
Sedation is a continuum of consciousness, and the practitioner providing sedation should be ready to respond appropriately to the next higher level of sedation in addition to being comfortable at the current sedation level. This is particularly relevant when sedation is administered by nonanesthesiologists such as dental practitioners, radiologists, dermatologists, cardiologists, and gastroenterologists [4–9].
Why Is Sedation a Particular Concern in Elderly Patients?
The geriatric population is a heterogeneous group, and chronologic age does not always parallel physiologic age. Older patients present with multiple comorbidities, numerous medications, and less physiologic reserve [10, 11] (see Chaps. 4, 7, 8, and 27). They can be more sensitive to the sedative and depressant effects of the drugs used for sedation and are at increased risk from additive side effects when combinations of medications are administered. Although brief episodes of hypotension or desaturation may be insignificant in a young patient, the same episodes in an elderly frail patient may result in serious consequences, such as cardiac ischemia and arrhythmias [12] (Table 22.2).
Table 22.2
Considerations for sedation in the elderly
1. Presence of multiple comorbidities: Coronary disease, arrhythmias, prior cerebrovascular accidents |
2. Positioning challenges |
3. Chronic pain especially of the back and spine |
4. Prevalence of chronic hypoxia and the need for home oxygen |
5. Hearing and vision impairments that interfere with communication |
6. Dementia and cognitive dysfunction |
Comorbid Conditions
Elderly patients carry a large burden of disease: In a study examining preoperative health status in elderly patients, more than 84% of 544 patients had at least one comorbid condition, with 30% of patients having three or more preoperative health conditions and 27% with two [10]. Disability restricting mobility is also prevalent: 73% of people older than 80 years have at least one disability. These conditions have an impact on the delivery of sedation and may limit the options available for sedation.
Cardiac conditions such as angina, hypertension, and congestive heart failure are all prevalent among elderly patients [13, 14]. The high incidence of coronary artery disease places older patients at high risk for myocardial ischemia during awake procedures, especially if the procedure is painful and/or anxiety provoking and it proves difficult to relieve the pain/anxiety without resorting to unacceptable levels of sedation. Similarly, hemodynamic instability, particularly hypotension, is more likely in older patients because of their sensitivity to hypovolemia and the increased sympathetic tone that could be reduced by sedation. However, hypotension is not a likely result if stage II sedation is not exceeded [2, 15].
Age-related pulmonary changes also affect the administration of sedation; changes in lung- and chest-wall compliance predispose the older patient to atelectasis with associated hypoxia that may not be amenable to treatment with supplemental oxygen [16]. Hypercarbia may also develop and produce hypoxia (if not on supplemental oxygen) and may produce undesired hypertension and tachycardia.
Renal disease may require alternations in medication dosing, and uremia can render patients very sensitive to the effects of sedation, especially the apneic side effects of narcotics. With the obesity epidemic in the United States, diabetes is becoming more prevalent and is very common in older patients. Glucose control can be problematic, and associated diabetic gastroparesis may result in a full stomach, even after 8 h of fasting.
Central nervous system aging renders older patients more sensitive to sedatives and analgesics, and patients with mild cognitive dysfunction are at particular risk of agitation and confusion with even small amounts of sedatives.
Challenges Encountered During Administration of Sedation
There are certain issues that are uniquely relevant to elderly patients that may impinge on the sedation plan [11, 17, 18] (Table 22.3).
Table 22.3
Practical considerations for the administration of sedation in elderly patients
• Allow extra time to explore the preoperative history including medications and comorbidities |
• Provide written instructions in large type |
• Provide extra copy of instructions to caretaker if applicable |
• Allow extra time for changing clothes at the beginning and end of the procedure |
• Be prepared to provide additional assistance transferring to and from procedure table |
• Postoperative recovery facilities with monitoring should be available in the event of a slow postoperative recovery |
Positioning
The accelerated loss of subcutaneous and intramuscular fat observed with aging may result in bony prominences that are at risk from skin breakdown and predispose elderly patients to accidental injury from seemingly benign positions . The loss of skin elasticity and slow healing further contribute to complex skin wounds and shearing injuries. Chronic pain, especially back pain, may limit the ability of an elderly patient to attain or maintain certain positions for long periods of time. Vertebrobasilar insufficiency may predispose an older patient to unexpected cerebral ischemia with neck extension; this may be particularly important if manipulation of the airway or neck is required. Cardiopulmonary compromise may occur secondary to positioning. For instance, the prone position or Trendelenburg may be less well tolerated in an elderly patient with significant cardiac disease.
Communication
Diminished visual acuity, blindness, deafness, or impaired hearing make it more difficult to communicate during a procedure. Furthermore, many common procedures such as colonoscopies and endoscopies take place in a darkened endoscopy suite, further reducing the sensory input to the older patient. Any written information should be easy to read, and extra copies should be available for patient’s family, especially if the patient has any cognitive or communication issues.
Preprocedure Evaluation
Before administering sedation, an assessment of the patient’s overall health including an estimate of the patient’s reserve function of major organ systems is needed. At a minimum, this should include a medical history, a comprehensive list of medications, and a brief physical examination including an airway assessment. One of the guiding principles for the successful administration of sedation is cooperation; preprocedure assessment should include an evaluation of the patient’s ability to cooperate at baseline. Patients who cannot cooperate because of dementia, sensory issues such as hearing or visual loss, or who are in extreme pain or disabled from arthritis and prior strokes and so on may not be suitable sedation candidates, and a deep sedation or a general anesthetic may be required [2, 11, 19, 20].
Scheduling and Information
The geriatric patient may have limited mobility and other issues that may result in the need for extra time to change and transfer from a chair to a stretcher. Therefore, additional time in between cases and arrangements to help with dressing and so on should be allotted.
All instructions should be written avoiding medical jargon and available in large easy-to-read print. In addition to preoperative instructions, written information should be given to patients and/or caregivers before discharge that clearly states what to expect postoperatively, whom to contact with questions, and how to arrange for emergency help if needed.
Sedation History
A history of sedation and anesthesia is invaluable. Difficulties with prior procedures under sedation, substance and alcohol abuse, and extensive pain medication use have been shown to predict difficulty in sedation administration. In addition, technically difficult or lengthy procedures also predict difficulty with sedation. In these instances, it may be preferable to schedule elective procedures for deep sedation or general anesthesia [2, 11, 19, 20] (Tables 22.4 and 22.5).
Table 22.4
Predictors of difficult sedation
History of: |
Substance abuse |
Heavy alcohol use |
Chronic narcotic use |
Difficulty with previous sedation case |
Anticipated prolonged or complex procedure |
Table 22.5
General anesthesia recommendations
General anesthesia is recommended in patients who are: |
• Obtunded |
• Intoxicated |
• Septic |
• Have active hematemesis |
• Have significant cognitive impairment—e.g., dementia or are unable to cooperate secondary to confusion or anxiety |
• At high risk from aspiration—e.g., obesity, reflux, or ascites |
• Unable to lie still secondary to pain, confusion, or other medical conditions |
Consent
The patient should understand and agree with the specific plan for sedation and the risks involved. When the patient is significantly disabled or dependent, it is important to involve caregivers early. Aside from consent issues in these patients, caregivers are likely to be needed in the postprocedure care of the patient. Frequently, the surgical consent will include permission for sedation during the procedure, and separate consent for sedation is not always needed; however, specifics will depend on local administration and regulations within the hospital or facility.
Preoperative Fasting Guidelines
Both the ASA and the American Society for Gastrointestinal Endoscopy (ASGE) recommend restricting solid foods for 6–8 h and allowing only clear liquids until 2–3 h before the procedures. In the elderly person, it is useful to establish who is receiving these instructions and who is responsible to enforce them. In a more frail or demented patient, adherence to fasting guidelines is particularly important because it can be difficult to predict the reaction to sedation and there may be a need for conversion to a deeper sedation or a general anesthesia [19, 20].
Procedural Considerations
Monitoring
Guidelines for monitoring have been developed by the ASA [21]. At minimum, all sedated patients must be monitored throughout the procedure for level of consciousness. Standard monitoring includes heart rate monitoring via pulse oximetry, noninvasive blood pressure at regular intervals, respiratory rate, and oxygen saturation, and in the elderly population, electrocardiography is also recommended. Postprocedure vital signs should also be monitored periodically during the recovery period until the effects of all medications have worn off and the patient is ready for discharge.
The presence of a pacemaker requires the availability of a magnet if cautery is contemplated. Patients with a significant cardiac history, ongoing angina, congestive heart failure, or oxygen-dependent lung disease have almost little reserve function. These patients may not be suitable candidates for sedation because they may require additional monitoring.
Patients may maintain normal oxygen saturation despite significant hypoventilation and hypercapnia, and monitoring of ventilation is advisable whenever deep sedation is contemplated, especially during long procedures. Capnography can be used to monitor ventilation and to detect early increases in carbon dioxide [21]. Similarly, the bispectral index (BIS) monitor has been used to assess the level of sedation in patients receiving propofol for sedation [22].
It should be recognized that clinical monitoring of the elderly patient may be more demanding than that of the younger patient. During the procedure, a dedicated individual should be able to supervise the patient. This individual should not be performing the procedure but rather should be continuously monitoring the patient for responsiveness, cooperation, and vital signs. Because by definition a sedated patient should be responsive at all times, communication with the patient is one of the most valuable monitoring methods.
Emergency Resuscitation
When administering sedation , emergency resuscitative equipment should be available, and those providing sedation should ideally be trained in basic and advanced life support. Minimal emergency equipment should include dedicated oral suction, oxygen, a bag-valve-mask device, an oral airway, and anesthetic drug (agonist) reversal (antagonists) drugs [23, 24].
Oxygen
Elderly patients with limited pulmonary system reserve function are predisposed to hypoventilation and hypoxemia; this may be exacerbated by cardiopulmonary and other diseases. Studies in gastroenterology have described episodes of desaturation during endoscopic and colonoscopic procedures in both sedated and nonsedated patients, emphasizing the vulnerability of these patients [25, 26]. Supplemental oxygen provided via nasal cannula at 4 L/min has been successful in abolishing or attenuating episodes of desaturation. As stated, monitoring of ventilation is indicated because oxygen may mask the development of hypercapnia in sedated patients, especially those receiving supplemental narcotics [2, 19, 21].
Conclusions
Elderly patients should be offered the opportunity to undergo procedures and simple surgeries under sedation with minimal risk. Skillful administration of sedation may help avoid more morbid and complex surgeries and improve outcomes. Sedation in the older patient is safe, but requires additional vigilance and patience.
Gastrointestinal Endoscopy in the Elderly
Some of the most common nonoperating room procedures in the elderly are gastrointestinal endoscopies. The incidence of gastrointestinal disease increases with age. Endoscopic procedures are often utilized to diagnose and treat many of these conditions. Specifically, the elderly have higher rates of colorectal cancer, esophageal cancer, and gastric cancer. Biliary and pancreatic diseases are also more prevalent in the elderly [27]. Indications for upper endoscopy, colonoscopy, balloon-assisted enteroscopy, percutaneous endoscopic gastrostomy (PEG), endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS) are essentially the same as for younger patients. However, screening colonoscopies have limited benefit after the age of 75 [28].
Aging and the Gastrointestinal Tract
Changes occur throughout the gastrointestinal (GI) tract during the aging process. Cellular changes include growth, differentiation, replication, and immunological changes [29]. Diverticular disease, malignancy, and GI motility issues are some manifestations of these changes [30, 31]. Dysphagia, diminished esophageal sphincter tone, decreased pharyngeal and supraglottic sensation, and diminished pharyngoglottal closure reflexes lead to increased incidence of aspiration and subsequent pneumonia or pneumonitis [32, 33]. Cholelithiasis and choledocolithiasis in the elderly may be influenced by increased gallbladder volume and altered gallbladder motor dynamics [34, 35]. Increased incidence of gastrointestinal bleeding is due to diminished protective mucosal function, changes in bicarbonate level, and higher use of blood-thinning medications including nonsteroidal anti-inflammatory medications [31].
Preprocedure Evaluation and Concerns
Endoscopy is considered a low-risk procedure. Preoperative cardiac testing is unnecessary in asymptomatic patients. A 12-lead ECG is also unnecessary in patients with known cardiovascular disease scheduled for GI endoscopy [36]. Some patients may present with recent coronary interventions including bare-metal and drug-eluting stents. Consultation between the endoscopist, cardiologist, and anesthesiologist may be required. It should be noted that in therapeutic ERCP and some cancer-staging endoscopic ultrasound (EUS) procedures, the benefit of performing the gastrointestinal procedure prior to cardiac intervention may be warranted. Elderly patients presenting to the endoscopy suite are often taking anticoagulant and antiplatelet medications. These medications are usually continued unless symptomatic bleeding is ongoing or can be expected (planned sphincterotomy, polypectomy, or endoscopic mucosal resection). The risk of bleeding should be weighed against the risk of thrombotic complications . Appropriate guidelines and expert opinion may be required when making this decision.
Implanted cardiac devices should be evaluated preprocedure. Monopolar electrosurgical current may be used during sphincterotomy, snare polyp resection, hot biopsy forceps application, and argon plasma coagulation [37]. As such, precautions should be taken regarding pacemaker and internal defibrillator function. If electromagnetic interference is anticipated, cardiologist and manufacturer recommendations should be obtained regarding appropriate device setting, interrogation, and magnet use.
Dehydration is common in the elderly. This is more likely to occur in hot climates or when taking diuretic and antihypertensive medications. Fluid restriction and bowel preparations make patients very susceptible to hypotension and in particular, orthostatic hypotension when standing. Polyethylene glycol and sodium phosphate oral preparation solutions are commonly used for bowel preparation. Sodium phosphate preparations are contraindicated in elderly patients with renal insufficiency, heart failure, and volume overload. Sodium phosphate can result in hyperphosphatemia, hypokalemia, and hypernatremia [38]. Polyethylene glycol preparations have been associated with acute renal failure, particularly in geriatric patients [39]. Some patients may receive split-dose bowel preparation solutions. Improved bowel preparation is achieved with split-dose regimens as long as the “runaway time” or period of time since the second dose of bowel preparation solution was ingested does not exceed 5 h [40]. Split-dose preparations result in similar residual gastric volumes to the residual gastric volumes of when compared to those patients who received an entire single-dose solution the night before examination [41]. In most patients, a 2 h fasting period after the second dose of bowel preparation solution should suffice in maintaining standard nothing by mouth (NPO) conditions prior to sedation.
Prophylactic Antibiotics
Prophylactic antibiotic indications should be the same regardless of patient age for GI endoscopic procedures. Typically, antibiotics are not indicated for endoscopic GI procedures. The American Society of Gastrointestinal Endoscopy and the American Heart Association have issued guidelines [42, 43]. In patients with high-risk cardiac conditions and established gastrointestinal tract infections with enterococci, antibiotic coverage for prevention of infective endocarditis with an antibiotic targeting enterococci may be reasonable [42].
For prevention of infections other than infective endocarditis, antibiotics are also recommended in specific circumstances. Antibiotics are recommended for ERCP in patients with biliary obstruction with incomplete drainage or in patients with biliary strictures post liver transplantation. All patients should receive antibiotics prior to PEG tube placement. Antibiotic prophylaxis prior to aspiration of a mediastinal or pancreatic cystic lesion during EUS is suggested. In peritoneal dialysis patients undergoing lower GI endoscopy, antibiotic prophylaxis for prevention of peritonitis is suggested [43].
Upper Endoscopy
Upper endoscopy in elderly patients has a high diagnostic yield [44]. Elderly patients with a history of upper gastrointestinal bleed (GIB) have the highest diagnostic yield (74%), while older patients with a family history of gastric cancer have the lowest yield (6%) [44]. The overall frequency of finding peptic ulcer disease and malignancy increases with age. Esophagogastroduodenoscopy (EGD) for indications other than emergency upper GIB is not associated with higher complication rates compared to younger patients [45]. It has been suggested that the use of an ultrathin endoscope (5–6 mm diameter vs. 8–11 mm) may allow for awake endoscopy or minimal sedation endoscopy due to the ease of insertion and less oropharyngeal irritation [46].
PEG tube placement is considered in patients expected to survive more than 30 days after placement. Postplacement mortality is high in the very elderly, but this is often related to the patient’s underlying disease and comorbidities [47].
Various strategies have been described for upper endoscopy in the elderly. Sharing the airway of the anesthetized patient with the endoscopist can be challenging, and careful selection of anesthetic drugs and doses is required. Supplemental oxygen via a nasal cannula with carbon dioxide detection capability is usually placed. A nasal trumpet connected to a breathing circuit may also be considered. The patient is usually placed in the lateral position and insertion of the endoscope is typically the most stimulating part of the procedure.
The age-related reduction in pharyngeal sensitivity compared with younger patients is an advantage when performing a simple upper endoscopy. The elderly patient may not require much if any sedation. Aspiration is always a risk in sedated patients. However, the endoscopist is usually able to actively suction GI contents during the performance of upper endoscopic procedures. In the frail elderly patient, aspiration can be a morbid event [17, 48]. Studies of elderly patient sedation strategies for upper endoscopy have shown good outcomes with lower doses of propofol [49, 50]. In a study by Gotoda et al., average maintenance propofol dose for complex upper endoscopy was 85 mcg/kg/min in patients <70 years and 60 mcg/kg/min in patients ≥80 years [50]. Hypoxemia , which is more common in elderly patients with abnormal pulmonary function, can be lessened with a stepwise, judicious approach to upper endoscopy sedation [50, 51]. A prospective study of 720 older patients (60–80 years) showed that the use of etomidate for sedation in elderly patients at significant risk for hypotension can be considered [52]. This should result in better hemodynamic parameters when compared to propofol-based sedation during gastroscopy. Complications of excessive sedation in upper endoscopy are usually due to hypoventilation, hypotension, and hypoxia; however, inadequate sedation may lead to coughing, laryngospasm, and active regurgitation of gastric contents.
Colonoscopy
Colonoscopies are generally associated with considerable discomfort. A prospective study by Lukens et al. found that in octogenarians undergoing colonoscopy, poor colonic preparation was four times more likely in octogenarians than nonoctogenarians resulting in lower completion rates [48]. Hypoxemia was also more common during colonoscopy for octogenarians compared to nonoctogenarians (27% vs. 19%), and desaturations were associated with higher meperidine doses [48]. In a larger prospective study of 2000 patients, overall complication rates during colonoscopy were low regardless of patient age [53]. However, risk of perforation during colonoscopy does appear to increase with age [47]. Also, a meta-analysis of adverse events in elderly colonoscopies showed that cardiopulmonary events were more prevalent in patients 80 and older (28.9/1000) versus patients 65 and older (19.1/1000) and were related to sedation and higher patient comorbidities [54].
During colonoscopy , deeper levels of sedation are associated with increased risk of aspiration, splenic injury, and colonic perforation [55]. It is also known that sedation will facilitate the colonic endoscopic examination and increase patient comfort. Deeper levels of sedation may predispose to an increased rate of colonic perforations due to patient inability to show discomfort associated with the scope being advanced against resistance. Similarly, splenic injury may be more likely to occur secondary to increased patient tolerance to colonoscope loops stressing colonic to splenic attachments. Active or passive regurgitation of gastric contents may also occur. Endotracheal intubation may be indicated in patients determined to be at high risk for gastric aspiration during colonoscopy. Short-acting anesthetic agents such as propofol are preferred for rapid titration and ability to reduce the period of time in deep sedation. Titration of propofol and other anesthetic agents to EEG-based monitoring (e.g., BIS) can help providers reduce time spent in deep sedation [50].
Deep Small Bowel Enteroscopy
Obscure gastrointestinal bleeding and other small bowel disorders in the elderly patient are often identified via balloon-assisted deep enteroscopy. The small bowel may be approached in either an anterograde or retrograde fashion. Heyde’s syndrome, an angiodysplastic bleeding syndrome due to acquired type-2A von Willebrand factor, results from aortic stenosis [56] (Fig. 22.1). It is important that this association not be overlooked as deep levels of sedation or general anesthesia with an endotracheal tube are typically required to facilitate deep enteroscopy. A prospective review showed deep enteroscopy to have a high diagnostic yield and require lower levels of sedation in patients over 70 compared to younger patients [57].
Fig. 22.1
Pathogenesis of Heyde’s syndrome . Gastrointestinal bleeding can be due to aortic stenosis and other degenerative conditions via a complex mechanism (Reprinted from Godino et al. [56]. With permission from Elsevier)
Endoscopic Retrograde Cholangiopancreatography
Endoscopic management of pancreaticobiliary disease in the elderly is particularly advantageous as high-risk surgical procedures may be avoided. The high incidence of biliary tumors, cholelithiasis, and pancreatic head cancer in the elderly make this procedure common. Complication rates are low and safety has been demonstrated in multiple studies [47].
ERCP procedures may last an hour or more and adequate sedation is essential. The patient is usually placed in the prone position with the head turned to the side. A recent large retrospective study revealed that during ERCP, sedation-related adverse events (myocardial infarction, cardiac and/or respiratory arrest, arrhythmias, hypoxemia, hypotension, bradycardia, tachycardia) were more common in patients over 80 years [58]. Propofol, at lower doses, was the most commonly used agent in this study and highlights the need for expert care and the skillful management of sedation needed for ERCP in the elderly. In our practice, we often prefer general anesthesia with an endotracheal tube, particularly for longer and more complex cases. Another study of high-risk octogenarians undergoing routine ERCP demonstrated superiority of a propofol-based anesthetic compared to a midazolam/meperidine sedation [59]. Benefits of propofol included better patient cooperation, shorter recovery time, and significantly lower desaturation events in recovery.
Endoscopic Ultrasound
Endoscopic ultrasound is used to stage malignancies, evaluate the biliary tree, and evaluate extraluminal solid and cystic masses. In patients with suspected pancreatic cancer, endoscopic ultrasound is known to be particularly useful. This procedure is often utilized with fine-needle aspiration and combined with ERCP. Endoscopic ultrasound has demonstrated good safety in patients 75 years and older [60]. However, the echoendoscope has a more rigid tip than the standard endoscope may predispose the patient to an increased risk of perforation [61]. Similar to ERCP , sedation times are longer and a sedation strategy should be planned for accordingly.
Summary
GI endoscopic procedures in the elderly are useful both diagnostically and therapeutically. Sedation techniques are similar to those used in younger patients, although effective doses are lower. Hypoxia, hypotension, arrhythmias, and aspiration are more common in the elderly [38]. In the limited number of studies that evaluate sedation in the elderly for endoscopic gastrointestinal procedures, short-acting agents including propofol appear to offer advantages over traditional agents like midazolam and meperidine. Meperidine and midazolam, particularly at higher doses, may have prolonged effects and are associated with delirium [62]. As the elderly are more prone to orthostatic hypotension, care must be taken when allowing them to stand and ambulate after endoscopy. This is of particular concern in patients who have had bowel preparations or have been fluid restricted.
Electroconvulsive Therapy and the Elderly
It is estimated that approximately 12.5% of older people have some form of depression [63]. Major depression in adults over the age of 60 is estimated at 2% [64]. The rate is likely higher for those patients that are inpatient or in nursing facilities. There is evidence to suggest that major depression in the geriatric population may be related to concomitant cerebrovascular disease as well as underlying cognitive impairment [65]. In addition, depression that occurs later in life can lead to worsening cognitive deficits, and elderly patients undergoing electroconvulsive therapy (ECT) may suffer greater cognitive impairment when compared to younger patients [66]. However, this association is variable among patients, and the underlying biological mechanisms that lead to cognitive dysfunction (see Chap. 30) are not well defined [65].
Multiple studies suggest that ECT can be effective and well tolerated in the elderly, even for the “old-old” adults of over 75 years of age [66–71]. Advances in ECT over the past few decades, including the use of ultrabrief pulse treatments, have improved the safety of ECT and limited cognitive side effects, but have not necessarily improved the treatment efficacy for geriatric patients with major depression [72]. In addition, many of these studies were not randomized, typically small in sample size, and often retrospective in nature [68–70, 73]. In fact, a Cochrane Review published in 2003 highlighted the sparse randomized evidence on the safety and efficacy of ECT in the treatment of depression in geriatric patients [63]. In addition, randomized evidence on the effectiveness of ECT in elderly patients with concomitant neurodegenerative disorders such as pre-existing dementia, Parkinson’s disease, and cerebrovascular disorders is absent [63]. However, elderly patients typically have more medical comorbidities requiring multiple medications. Polypharmacy, combined with age-related changes in drug metabolism , can make the elderly more prone to medication interactions and undesirable side effects with psychotropic medications used to treat depression. Thus, ECT may be the better option for treatment of major depression (Table 22.6). If untreated, severe depression in the elderly can also lead to loss of independence and a more frail state.
Table 22.6
Psychiatric diagnoses for which ECT has been alleged to be effective
• Major depression, single or recurrent episode |
• Bipolar major depression, depressed or mixed type |
• Mania (bipolar disorder), mania or mixed type |
• Schizophrenia ◦ Catatonia ◦ Schizophreniform or schizoaffective disorder |
• Atypical psychosis |
• Other conditions ◦ Organic delusional disorder ◦ Organic mood disorder ◦ Acute psychotic disorder ◦ Obsessive-compulsive disorder ◦ Dysthymia |
• Miscellaneous conditions ◦ Parkinson’s disease ◦ Neuroleptic malignant syndrome ◦ Secondary catatonia ◦ Lethal catatonia |
Other Treatments for Depression in the Elderly
Subconvulsive neuromodulation therapies that can potentially improve mood disorders in the elderly include transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS). These treatments do not require anesthesia, nor do they provoke a seizure, which may make them less likely to affect cognition [72]. Other therapies approved for chronic depression in the United States include vagal nerve stimulation (VNS). Implantation of VNS typically requires general anesthesia to implant both the generator (usually around the left chest area) and the electrode (usually the left neck area near the vagus nerve) [72].
Preoperative Evaluation
Preoperative work-up for the geriatric patient undergoing ECT does not significantly differ from any other elderly patient. However, informed consent in a severely depressed patient who may also have cognitive comorbidities such as pre-existing dementia can present unique challenges. Many institutions provide these patients with educational materials such as videos, brochures, and classes to aid with the informed consent process.
Elderly patients have a higher prevalence of stroke, valvular disease, and atrial fibrillation as compared to younger populations. Thus, these patients may be taking anticoagulation medications when presenting for a course of ECT. The transient increase in blood pressure due to the sympathetic response to electrical stimulus can potentially increase risk of bleeding in patients who are chronically anticoagulated. Historically, oral anticoagulation was often held during ECT treatment; use of intravenous heparin as a bridge during ECT treatment has been described. There is very limited data to suggest how anticoagulants should be managed throughout the course of ECT treatment. Case reports and retrospective reviews of patients on long-term warfarin therapy have not demonstrated increased risk of intracerebral hemorrhage during ECT treatment [74–76]. There is one case report of a patient on chronic anticoagulation who then developed gross hematuria immediately after ECT treatment [77]. However, larger prospective evaluations are needed, especially given the expansion of oral anticoagulants such as direct thrombin inhibitors now on the market.
Elderly patients with underlying cardiac disease may also present with cardiac pacemakers and/or implantable cardiac defibrillators (ICDs) . Unfortunately, there are no controlled trials that definitively outline the safest management for patients with these devices that undergo a series of ECT treatments. Analysis of multiple case reports and case series on this topic, however, suggest that ECT is safe in patients who have cardiac pacemakers, and the short duration of stimulus during ECT treatment does not have significant clinical effect on modern pacemakers [78]. In fact, the vast majority (80%) of patients in one retrospective pooled analysis had no modification to their pacemaker prior to ECT, while approximately 10% had their pacer changed to asynchronous mode. Risk of ventricular tachycardia (VT) or ventricular fibrillation (VF), however, still exists with conversion to asynchronous mode during ECT treatment, most likely due to the deceleration-acceleration nature of heart rate related to the induced seizure [78]. However, for those patients with ICDs, nearly all had their ICD deactivated during the procedure [78]. Thus, it may be prudent to disable ICD devices prior to treatment, but allow pacemakers not associated with an ICD to continue to function as programmed.
Physiologic Changes during Electroconvulsive Therapy
The application of transcutaneous electrical stimulation to the brain can cause many physiologic perturbations. However, most of these changes are short-lived. The brain itself sees an increase in cerebral blood flow, as much as 133% above baseline, resulting in increased intracranial pressure [79, 80]. This increase in cerebral blood flow velocity may be attenuated but not completely eliminated by the administration of systemic antihypertensive medications [80]. Serious but rare cerebral side effects include intracranial hemorrhage, transient ischemic changes, and blindness.
Cardiovascular changes during and immediately after the electrical stimulus include an initial parasympathetic stimulus with resultant bradycardia or even asystole that can last for several seconds. This is immediately followed by sympathetic stimulation and catecholamine release leading to hypertension, tachycardia, and increased myocardial oxygen demand that can last for several minutes. In fact, up to a 20% increase in heart rate, 34% increase in blood pressure, and 80% increase in cardiac output has been reported in the literature [81]. However, these hemodynamic changes do not appear to directly correlate with the duration of seizure, as measured by motor or EEG activity [82]. There is also some suggestion that left ventricular systolic function transiently decreases after the seizure [83]. Rare but life-threatening cardiac side effects reported from ECT include ventricular dysrhythmias, conduction abnormalities, myocardial infarction, and even cardiac rupture [84–87] (Table 22.7).
Table 22.7
Common physiologic responses and side effects associated with electroconvulsive therapy
Variable | Response |
|---|---|
Central nervous system | Increased blood flow velocity, intracranial pressure, and cerebral metabolism, dizziness, amnesia, confusion, agitation, and headaches |
Cardiovascular system | Increased blood pressure, heart rate, and cardiac output, cardiac arrhythmias |
Musculoskeletal system | Myoclonic-toxic contractions, bone fractures/dislocations, muscle and joint pain |
Miscellaneous responses | Increased salivation, nausea and vomiting, dental damage, and oral cavity lacerations |
Medications for Electroconvulsive Therapy
Older age is associated with elevated seizure thresholds [72]. In addition, the duration of the induced seizure is related to the efficacy of treatment . Thus, the anesthesiologist must balance the use of medications that often suppress seizure generation but still maintain an adequate general anesthetic state for several minutes. Mainstay sedative-hypnotic drugs for ECT include methohexital, thiopental, propofol, and etomidate. All have been described to be effective and safe in the use of ECT and confer individual advantages and disadvantages based on their pharmacokinetics, pharmacodynamics, and side effect profiles. In addition, there is no conclusive evidence to suggest that one agent is superior than another in terms of impacting depression scores [88]. Methohexital is often considered the best induction agent for ECT due to its epileptogenic effects, rapid onset, and short duration of action [79]. Propofol and thiopental tend to result in shorter seizure duration when compared to methohexital [88]. Etomidate has been associated with a statistically significant longer motor and EEG seizure duration when compared to propofol, methohexital, and thiopental [89]. Benefits of etomidate include rapid onset and cardiovascular stability. Side effects include pain on injection, adrenal suppression, and myoclonus [89]. Remifentanil , an ultra-short-acting opioid that does not increase seizure threshold, has also been used during ECT treatment. A recent meta-analysis suggests that the use of remifentanil as an adjunct to other induction drugs can significantly prolong seizure duration during ECT if the dose of the other induction drugs (such as thiopental or propofol) is decreased [90]. Also, the addition of remifentanil appears to significantly decrease the maximum systolic blood pressure [90]. Ketamine, in both sub-anesthetic and general anesthetic doses, may also be used in ECT, especially in treatment-resistant depression. There is emerging evidence that an infusion of ketamine has antidepressant effects and can improve mood in patients with treatment-resistant depression. In addition, ketamine has been shown to result in longer seizure duration as well as a faster improvement in mood after the first and second ECT treatment when compared to propofol [91]. In addition, there is recent evidence that ketamine infusions have antidepressant effects and can improve mood and could possibly emerge in the future as an alternative to ECT for patients with treatment-resistant depression [92].
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