critical care medicine
Agitation, Confusion, and Neuromuscular Blockade in Critically Ill Patients
Treatment of Agitation and Confusion
Underlying conditions (eg, hypoxia, shock, sepsis, drugs, progression of traumatic brain injury) 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. Tracheal 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. 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.Fentanylis the opioid of choice for short-term treatment because of its potency, short duration of action, and minimal cardiovascular effects. A common regimen can be 30 to 100 mcg/hour offentanyl; individual requirements are highly variable. Despite analgesia, many patients remain sufficiently agitated so as to require sedation. A sedative can also provide patient comfort at a lower dose of analgesic. Benzodiazepines (eg,lorazepam,midazolam) are most common. A common regimen for sedation islorazepam1 to 2 mg IV every 1 to 2 hours or a continuous infusion at 1 to 2 mg/hour 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 asdiazepam,flurazepam, andchlordiazepoxideshould be avoided in older adults. Antipsychotics with less anticholinergic effect, such ashaloperidol1 to 3 mg IV, may work best when combined with benzodiazepines. 400 mg/dL) may herald PRIS ( Treatment reference ), triglyceride levels must be measured after 2 to 3 days of high-dose Dexmedetomidinehas anxiolytic, sedative, and some analgesic properties and does not affect respiratory drive. The risk of delirium is lower than with benzodiazepines. Because of these lower rates,dexmedetomidineis an increasingly used alternative to benzodiazepines for patients requiring mechanical ventilation. The character and depth of sedation caused bydexmedetomidinemay permit mechanically ventilated patients to interact or be easily awakened, yet remain comfortable. The most common adverse effects are hypotension and bradycardia. Typical dosing is 0.2 to 0.7 mcg/kg/hour, but some patients require doses up to 1.5 mcg/kg/hour.Dexmedetomidineis usually used only for brief periods (eg,<48 hours). Ketamineis a dissociative anesthetic that provides analgesia and sedation.Ketamineacts as a NMDA (N-methyl-D-aspartate) noncompetitive antagonist. Benefits ofketamineinclude maintenance of respiratory drive and minimal cardiovascular depression.Ketaminealso has bronchodilator effects, which may be beneficial in patients with asthma. The most common adverse effects include laryngospasm and visual hallucinations. Typical dosing is 1 to 2 mg/kg IV, followed by 0.5 to 1 mg/kg IV as needed. For intubated patients, neuromuscular blockade isnota 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. When sedative drugs (includingdexmedetomidine) are used, neuromuscular blockade is rarely required. 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 includevecuronium(continuous infusion as directed by stimulation). 1.Diaz JH, Prabhakar A, Urman RD, et al:Propofolinfusion syndrome: A retrospective analysis at a level 1 trauma center.Crit Care Res Pract2014;2014:346968, 2014. doi: 10.1155/2014/346968 