Airway management in the geriatric patient for emergency medicine and critical care

INTRODUCTION — United States Census data estimate that 77 million Americans, or nearly 20 percent of the overall population, will be over age 65 by the year 2030 [1]. Similar trends are apparent throughout the developed world. The increase in the number of older adults has been accompanied by an increase in the use of health care, including the emergency department (ED), by patients with significant comorbid conditions such as diabetes, coronary artery disease (CAD), chronic obstructive pulmonary disease (COPD), and cancer.

Many older patients with comorbid disease will require airway management during the course of their illness. Increased patient age and its associated comorbidities affect airway management in four principal areas:

●Increased likelihood of requiring intubation during acute illness

●Increased difficulty performing bag-mask ventilation and intubation

●Increased difficulty maintaining oxygenation and preventing complications due to reduced cardiopulmonary reserve

●Need for adjustments in drug selection and dosing for rapid sequence intubation (RSI)

Airway management in geriatric patients will be reviewed here. Topic reviews covering general airway management and the performance of RSI are found separately.

●General airway management: (See "Overview of advanced airway management in adults for emergency medicine and critical care" and "Basic airway management in adults" and "The decision to intubate" and "Approach to the difficult airway in adults for emergency medicine and critical care".)

●RSI in adults: (See "Rapid sequence intubation in adults for emergency medicine and critical care" and "Neuromuscular blocking agents (NMBAs) for rapid sequence intubation in adults for emergency medicine and critical care" and "Pretreatment medications for rapid sequence intubation in adults for emergency medicine and critical care" and "Induction agents for rapid sequence intubation in adults for emergency medicine and critical care".)

EFFECTS OF AGING AND NEED FOR INTUBATION

Physiologic changes — Aging brings a number of physiologic changes that affect respiratory and cardiovascular function and that complicate airway management (table 1). Among the most important are [2]:

●Lung parenchymal changes resulting in impaired gas exchange and reduced PaO₂

●Decreased lung elasticity and increased ventilation-perfusion mismatch

●Decreased chest wall compliance and respiratory muscle strength, leading to increased work of breathing and higher risk of respiratory failure

●Reduced cough and mucociliary clearance, and possibly neuromuscular deconditioning, increasing the risk from aspiration

●Reduced responsiveness of brain respiratory centers to hypoxemia and hypercarbia

●Diminished overall cardiopulmonary reserve (and possibly coronary artery disease), resulting in heightened sensitivity to the negative inotropy and vasodilatory effects of induction agents and other vasoactive drugs, potentially causing cardiovascular collapse (see "Normal aging")

Chronic disease — It is important to distinguish between changes due to the physiology of aging and pathologic changes brought on by chronic disease. Despite the contributory role played by the physiologic factors described above, data suggest that comorbid conditions, and not age, play the most important role in determining patient outcome after respiratory failure in older adults [2]. As an example, a vigorous octogenarian who exercises daily has far more physiologic reserve and will tolerate the stress of acute illness far better than a bed-bound counterpart with cerebrovascular or cardiovascular disease.

Nevertheless, chronic illness and disability are more common in older adults. Exacerbations of chronic pulmonary and cardiac diseases often exhaust the patient's limited cardiopulmonary reserve, leading to respiratory distress or failure and the need for intubation. Such patients may not tolerate the greater work of breathing, leading to respiratory failure much earlier than in their healthier or younger counterparts. In addition, acquired illnesses, such as community or hospital acquired pneumonia or urinary tract infection, can progress to sepsis and rapidly deplete physiologic reserves in susceptible geriatric patients. (See "Chronic obstructive pulmonary disease: Diagnosis and staging" and "Epidemiology of heart failure", section on 'Older adults' and "Immune function in older adults".)

Ethical considerations — Clinicians providing emergency or critical care to older adults must consider patient wishes. When appropriate, clinicians should enquire regarding the presence of advanced directives (code status) and attempt to determine patient desires regarding invasive measures such as intubation by review of existing documentation or discussion with the patient, the patient's family, or the primary care physician.

"Do not intubate" and "do not resuscitate" status must not be assumed, and patient age alone is never an indication to withhold care in the context of an acute illness. Studies suggest that clinicians caring for older adults at the end of life often underestimate the level of resuscitation desired by the patient [3].

When the clinician managing the patient with acute deterioration is not able to determine the patient's wishes or code status, it generally is best to proceed with resuscitation and intubation, and to end life-sustaining treatment later should information about advanced directives become available. (See "Ethical issues in palliative care".)

AIRWAY DIFFICULTY — Both bag-mask ventilation and intubation are more likely to be difficult in older adults. The assessment and general approach to the difficult airway in adults is discussed separately; issues of particular relevance to geriatric patients are discussed here (table 1). (See "Approach to the difficult airway in adults for emergency medicine and critical care".)

Geriatric, edentulous patients are harder to ventilate with a bag-valve mask and less tolerant of hypoxia. The loss of upper airway muscle tone and loose lips unsupported by teeth make mask seal and maintenance of a patent airway more difficult [4]. Geriatric patients are more likely to have arthritis of the cervical spine, reducing neck mobility and making laryngoscopy, especially direct laryngoscopy, more challenging. A stiffer chest wall increases the difficulty of ventilation with a bag-valve mask or a rescue airway (eg, laryngeal mask airway). Many older patients have intrinsic lung conditions (chronic obstructive pulmonary disease [COPD], lung cancer, sepsis complicated by acute respiratory distress syndrome) that may contribute to intrapulmonary shunting and increased difficulty preoxygenating without the use of bilevel positive airway pressure (BiPAP).  

Baseline oxygen saturation is often low in older adults, and adequate preoxygenation may be difficult to achieve. In addition, older adults who are critically ill or injured desaturate more rapidly than healthy, younger patients. In the following figure, the curve for chronically ill patients can be used to approximate desaturation for older adults (figure 1). Thus, the safe apnea period is decreased despite best attempts at preoxygenation compared with routine intubations in younger, healthy adults. Strategies for maximizing preoxygenation are reviewed separately. (See "Rapid sequence intubation in adults for emergency medicine and critical care", section on 'Preoxygenation'.)

Geriatric patients are more susceptible to hypoxic insults. Even brief periods of oxygen desaturation can result in permanent cardiac and neurologic damage. Whenever possible, the airway manager should maintain the oxyhemoglobin saturation at or above 90 percent, even if this requires controlled interposed bagging in the window between rapid sequence intubation (RSI) medication administration and onset of paralysis or aborting an attempt at laryngoscopy in order to oxygenate by bag and mask or with an extraglottic device [5]. (See "Basic airway management in adults", section on 'Bag-mask ventilation' and "Extraglottic devices for emergency airway management in adults".)

When an airway assessment for difficulty uncovers major anatomic challenges or significant physiologic derangement, particularly a high risk of rapid desaturation with onset of apnea, and alternative video devices are not available, we suggest using an awake approach to intubation. (See "Approach to the difficult airway in adults for emergency medicine and critical care", section on 'Awake techniques'.)

Video laryngoscopes improve both glottic exposure and intubation success and may allow safe RSI in patients for whom direct laryngoscopy with a conventional laryngoscope is not likely to be successful. (See "Devices for difficult airway management in adults for emergency medicine and critical care", section on 'Video laryngoscopes'.)

PHYSIOLOGIC OPTIMIZATION AND DRUG SELECTION FOR RAPID SEQUENCE INTUBATION

Overview of medications and dosing — Despite the higher incidence of difficult airways in older adults, most are appropriate candidates for rapid sequence intubation (RSI). When performing RSI, drug selection and drug dosing are of great importance (table 1). The medications used for RSI may cause more pronounced hypopnea and hypotension in older adults than in younger, healthy patients [6,7]. Age has been associated with an increased risk of peri-intubation hypotension and cardiac arrest in emergency patients [7-9]. Therefore, it is generally best to reduce the doses of induction agents by approximately 30 to 50 percent if the systolic blood pressure is <100 mmHg or the patient exhibits clinical signs of shock or hypoperfusion. In this setting, resuscitation with isotonic fluid boluses, blood, and norepinephrine should be initiated before RSI medications are given as long as the need for intubation is not immediate (ie, anaphylaxis). Standard dosing is used for neuromuscular blocking agents.

The general performance of RSI and the medications used in the procedure are discussed separately. Issues of particular importance to RSI in geriatric patients are reviewed here. (See "Rapid sequence intubation in adults for emergency medicine and critical care" and "Neuromuscular blocking agents (NMBAs) for rapid sequence intubation in adults for emergency medicine and critical care" and "Pretreatment medications for rapid sequence intubation in adults for emergency medicine and critical care" and "Induction agents for rapid sequence intubation in adults for emergency medicine and critical care".)

Physiologic optimization — The same factors that increase the potential need for airway management often predispose geriatric patients to hemodynamic instability before, during, and after intubation. Whenever time allows, the clinician should intervene to optimize the cardiopulmonary status of older adult patients at risk for circulatory collapse. Such risk stems from a combination of poor cardiac reserve, pathophysiology of active disease (eg, sepsis, dehydration, hemorrhage), effects of the induction agent, positive pressure ventilation, and other factors. Boluses of intravenous (IV) fluid, blood transfusion, and vasopressor agents are examples of interventions that may be needed prior to drug administration, if time permits. (See "Rapid sequence intubation in adults for emergency medicine and critical care", section on 'Physiologic optimization'.)

In a before and after trial of patients intubated urgently in an ICU, rates of cardiac arrest and refractory shock were significantly lower after the implementation of a shock-sensitive protocol for airway management that focused on providing IV fluids, selecting induction agents that promote hemodynamic stability, and early use of vasopressors [10].

Induction — Etomidate is the preferred induction agent for geriatric patients undergoing RSI. Etomidate is a sedative-hypnotic medication that maintains hemodynamic stability and has a rapid and reliable onset of action and a short duration of effect [11-14]. Hemodynamic stability is of particular importance in geriatric patients, who are at risk of large fluctuations in blood pressure from potent sedatives. The pharmacology and use of etomidate is discussed separately. (See "Induction agents for rapid sequence intubation in adults for emergency medicine and critical care", section on 'Etomidate'.)

Despite the relatively safe profile of etomidate, in a patient with severe, refractory hypotension, the drug (similarly to any induction agent) can exacerbate hypotension, a matter of particular concern in older adults with underlying cerebrovascular or cardiovascular disease. In older adults with tenuous cardiovascular reserve or hypotension (systolic blood pressure <100 mmHg), we recommend reducing the induction dose of etomidate by 50 percent to 0.15 mg/kg.

Midazolam is a short-acting benzodiazepine sometimes used for induction during RSI. Given its slower onset of action, presence of long-acting metabolites, and risk of hypotension, midazolam should be considered a "last resort" induction agent in older adult patients. Midazolam is more likely to cause hypotension than etomidate and should be given in reduced doses (0.1 mg/kg) in any patient 65 years of age or older and in those with hypotension. (See "Induction agents for rapid sequence intubation in adults for emergency medicine and critical care", section on 'Benzodiazepines'.)

Propofol is used primarily for maintenance of sedation following airway management but can be used for induction. The typical RSI dose is 1.5 mg/kg IV. Propofol can precipitate hypotension more easily than etomidate and should be used with caution in geriatric patients with compromised hemodynamics. Doses should be reduced by 50 percent in this setting.  

Ketamine is a dissociative anesthetic used as an induction agent for RSI, particularly in patients presenting with hypotension as ketamine increases blood pressure. However, ketamine can cause cardiovascular collapse in patients with profound refractory shock or in a catecholamine-depleted state. Evidence suggests that ketamine may precipitate clinically significant hypotension more often than etomidate during emergency RSI, particularly in patients with presumed sepsis. In addition, ketamine can aggravate tachycardia and increase myocardial demand and so should be used judiciously if at all in geriatric patients with a tachydysrhythmia or advanced coronary disease. The relative advantages and disadvantages of ketamine for induction of RSI are reviewed separately. (See "Induction agents for rapid sequence intubation in adults for emergency medicine and critical care", section on 'Ketamine'.)

Neuromuscular blockade — The results of two small trials, one randomized and the other observational, suggest that the dose of neuromuscular blocking agent (NMBA) needed to achieve full paralysis is lower and the duration of effect longer in geriatric patients [15,16]. Nevertheless, we believe the risks associated with poor intubating conditions and failed intubation attempts from incomplete paralysis outweigh any potential risk of prolonged paralysis. Therefore, pending further studies, we suggest using standard dosing for NMBAs when intubating geriatric patients.

Succinylcholine, in its usual dose of 1.5 mg/kg of actual body weight, is the drug of choice for RSI in older adults, unless contraindications are present. In geriatric patients, the most common contraindication to succinylcholine is subacute neurologic injury. A complete description of the contraindications to succinylcholine is provided separately. (See "Neuromuscular blocking agents (NMBAs) for rapid sequence intubation in adults for emergency medicine and critical care", section on 'Contraindications and side effects'.)

Geriatric patients are much more likely than their younger counterparts to have experienced denervating stroke. Denervation occurring between three days and six months prior to RSI predisposes the patient to severe and rapid-onset hyperkalemia if succinylcholine is used. Therefore, if clinical evidence of a prior denervating stroke is present, and it cannot be ascertained with certainty that the stroke occurred more than six months earlier, we recommend using rocuronium for neuromuscular blockade during RSI. The dose of rocuronium is 1.5 mg/kg using total body weight. (See "Neuromuscular blocking agents (NMBAs) for rapid sequence intubation in adults for emergency medicine and critical care", section on 'Nondepolarizing agents'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Airway management in adults".)

SUMMARY AND RECOMMENDATIONS

●Effects of aging on emergency airway management – The physiologic changes and increased rates of chronic illness associated with aging increase the likelihood that emergency airway management will be necessary during acute illness. (See 'Effects of aging and need for intubation' above.)

Bag-mask ventilation and endotracheal intubation are more likely to be difficult in the geriatric patient. (See 'Airway difficulty' above.)

Important aspects of emergency airway management in the older adult patient are summarized in the table (table 1).

●Rapid sequence intubation (RSI) in older adults – RSI is an appropriate approach for most older adult patients.

Selection of induction agent – Maintaining hemodynamic stability is of particular importance for geriatric patients, who are at risk of large fluctuations in blood pressure from potent sedatives. Clinicians should optimize cardiopulmonary status prior to performing RSI whenever time permits. (See "Rapid sequence intubation in adults for emergency medicine and critical care", section on 'Physiologic optimization'.)

For geriatric patients undergoing RSI, we suggest using induction agents that maintain hemodynamic stability (eg, etomidate) compared to alternative agents (Grade 2B), and using reduced doses for these medications in patients with tenuous cardiovascular reserve or hypotension. (See 'Induction' above.)

Dosing adjustments – Some medications used for RSI cause more pronounced hypopnea and hypotension in geriatric patients, particularly those with comorbid illness. In frail, hemodynamically compromised, or comorbidly ill patients, it is generally best to reduce the doses of etomidate or propofol (used for induction) by 50 percent or more. Standard dosing is used for neuromuscular blocking agents; rocuronium should be dosed at 1.5 mg/kg intravenous (IV). (See 'Overview of medications and dosing' above and 'Neuromuscular blockade' above and 'Physiologic optimization' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Christian Arbelaez, MD, MPH, who contributed to an earlier version of this topic review.