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ICU patients are often agitated, confused, and uncomfortable. They can become delirious (ICU delirium). These symptoms are unpleasant for patients and often interfere with care and safety. At worst, they may be life threatening (eg, patients dislodge the endotracheal tube or IV lines).
Etiology
In a critically ill patient, agitation, confusion, or both can result from the original medical condition, from medical complications, or from treatment or the ICU environment (see Table 8: Approach to the Critically Ill Patient: Some Causes of Agitation or Confusion in Critical Care Patients ). It is important to remember that neuromuscular blockade merely masks pain and agitation, it does not prevent it; paralyzed patients may be suffering significantly.
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Table 8
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| Some Causes of Agitation or Confusion in Critical Care Patients |
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Mechanism
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Examples
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Underlying disorder
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Head injury
Shock
Toxin ingestion
Pain and discomfort (eg, caused by injuries, surgical procedures, endotracheal intubation, IVs, blood drawing, or NGT)
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Complications
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Hypoxia (see Approach to the Critically Ill Patient: Oxygen Desaturation)
Hypotension
Sepsis
Organ failure (eg, hepatic encephalopathy)
Pulmonary embolism
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Drugs
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Sedatives and other CNS-active drugs, particularly opioids, benzodiazepines, H2 blockers, and antihistamines
Withdrawal from alcohol, drugs, or both
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ICU environment*
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Sleep deprivation (eg, due to noise, bright lights, or round-the-clock medical interventions)
Fear of death
Anxiety about unpleasant medical procedures
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*Particularly a problem for the elderly.
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Evaluation
The chart should be reviewed and the patient examined before sedatives are ordered for “agitation.”
History
The presenting injury or illness is a prime causative suspect. Nursing notes and discussion with personnel may identify downward trends in BP and urine output (suggesting CNS hypoperfusion) and dysfunctional sleep patterns. Drug administration records are reviewed to identify inadequate or excessive analgesia and sedation.
Past medical history is reviewed for potential causes. Underlying liver disease suggests possible hepatic encephalopathy. Known substance dependency or abuse suggests a withdrawal syndrome.
Awake, coherent patients are asked what is troubling them and are questioned specifically about pain, dyspnea, and previously unreported substance dependency.
Physical examination
O2 saturation < 90% suggests a hypoxic etiology. Low BP and urine output suggest CNS hypoperfusion. Fever and tachycardia suggest sepsis or delirium tremens. Neck stiffness suggests meningitis, although this finding may be difficult to demonstrate in an agitated patient. Focal findings on neurologic examination suggest stroke, hemorrhage, or increased intracranial pressure (ICP).
The degree of agitation can be quantified using a scale such as the Riker Sedation-Agitation Scale (see Table 9: Approach to the Critically Ill Patient: Riker Sedation-Agitation Scale) or the Ramsay Sedation Scale. Use of such scales allows better consistency between observers and the identification of trends. Patients who are under neuromuscular blockade are difficult to evaluate because they may be highly agitated and uncomfortable despite appearing motionless. It is typically necessary to allow paralysis to wear off periodically (eg, daily) so that the patient can be assessed.
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Table 9
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| Riker Sedation-Agitation Scale |
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Score
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Description
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Explanation
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7
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Dangerous agitation
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Tries to remove monitors and devices or climb out of bed; tosses and turns; lashes out at staff
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6
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Very agitated
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Remains restless despite frequent verbal reassurance; bites endotracheal tube; requires restraint
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5
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Agitated
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Anxious or restless; attempts to move; calms down with reassurance
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4
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Calm and cooperative
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Calm; easy to arouse; able to follow instructions
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3
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Sedated
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Difficult to awaken; responds to verbal prompts or gentle shaking but drifts off again
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2
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Very sedated
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Incommunicative; responds to physical stimuli but not verbal instructions; may move spontaneously
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1
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Unarousable
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Incommunicative; little or no response to painful stimuli
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Testing
Identified abnormalities (eg, hypoxia, hypotension, fever) should be clarified further with appropriate testing. Head CT need not routinely be done unless focal neurologic findings are present or no other etiology is found. A bispectral index (BIS) monitor may be helpful in determining the level of sedation/agitation of patients under neuromuscular blockade.
Treatment
Underlying conditions (eg, hypoxia, shock, drugs) should be addressed. The environment should be optimized (eg, darkness, quiet, and minimal sleep interruption at night) as much as is compatible with medical care. Clocks, calendars, outside windows, and TV or radio programs also help connect the patient with the world, lessening confusion. Family presence and consistent nursing personnel may be calming.
Drug treatment is dictated by the most vexing symptoms. Pain is treated with analgesics; anxiety and insomnia are treated with sedatives; and psychosis and delirium are treated with small doses of an antipsychotic drug. Intubation may be needed when sedative and analgesic requirements are high enough to jeopardize the airway or respiratory drive. Many drugs are available; generally, short-acting drugs are preferred for patients who need frequent neurologic examination or who are being weaned to extubation.
Analgesia
Pain should be treated with appropriate doses of IV opioids; conscious patients with painful conditions (eg, fractures, surgical incisions) who are unable to communicate should be assumed to have pain and receive analgesics accordingly. Mechanical ventilation is somewhat uncomfortable, and patients generally should receive a combination of opioid and amnestic sedative drugs. Fentanyl is the opioid of choice because of its potency, short duration of action, and minimal cardiovascular effects. A common regimen can be 30 to 100 μg/h of fentanyl; individual requirements are highly variable.
Sedation
Despite analgesia, many patients remain sufficiently agitated as to require sedation. A sedative can also provide patient comfort at a lower dose of analgesic. Benzodiazepines (eg, lorazepam, midazolam) are most common, but propofol, a sedative-hypnotic drug, may be used. A common regimen for sedation is lorazepam 1 to 2 mg IV q 1 to 2 h or a continuous infusion at 1 to 2 mg/h if the patient is intubated. These drugs pose risks of respiratory depression, hypotension, delirium, and prolonged physiologic effects in some patients. Long-acting benzodiazepines such as diazepam, flurazepam, and chlordiazepoxide should be avoided in the elderly. Antipsychotics with less anticholinergic effect, such as haloperidol 1 to 3 mg IV, may work best when combined with benzodiazepines.
Neuromuscular blockade
For intubated patients, neuromuscular blockade is not a substitute for sedation; it only removes visible manifestations of the problem (agitation) without correcting it. However, neuromuscular blockade may be required during tests (eg CT, MRI) or procedures (eg, central line placement) that require patients to be motionless or in patients who cannot be ventilated despite adequate analgesia and sedation. Prolonged neuromuscular blockade should be avoided unless patients have severe lung injury and cannot do the work of breathing safely. Use for > 1 to 2 days may lead to prolonged weakness, particularly when corticosteroids are concomitantly given. Common regimens include vecuronium (continuous infusion as directed by stimulation).
Key Points
Last full review/revision October 2012 by Soumitra R. Eachempati, MD
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