Sedation and Delirium Management

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Chapter 9

Sedation and Delirium Management

Mary E. Lough

Objectives

• Explain the differences among light, moderate, and deep levels of sedation.

• Describe the role of standardized assessment tools to determine sedation requirements.

• Compare and contrast the pharmacological agents used to provide sedation.

• List the risk factors for development of delirium in critical illness.

• Describe the management of delirium tremens in critical illness.

Be sure to check out the bonus material, including free self-assessment exercises, on the Evolve web site at http://evolve.elsevier.com/Urden/priorities/.

One of the challenges facing clinicians is how to provide a therapeutic healing environment for patients in the alarm-filled, emergency-focused critical care unit. Many critical care patients demonstrate some degree of agitation and discomfort caused by painful procedures, invasive tubes, sleep deprivation, fear, anxiety, and physiological stress.

Clinical practice guidelines were developed by the Society of Critical Care Medicine (SCCM) to increase awareness of these issues in the critically ill.¹ The goal is to find a balance between providing compassionate patient care and avoiding the perils of oversedation.

Sedation

Sedation Scales

The use of scoring systems to assess and record levels of sedation and agitation is now strongly recommended.1 Four frequently used scales are the Ramsay Scale,² the Riker Sedation-Agitation Scale (SAS),³ the Motor Activity Assessment Scale (MAAS),⁴ and the Richmond Agitation-Sedation Scale (RASS)^5,6 (Table 9-1). Because individuals do not metabolize sedative medications at the same rate, the use of a standardized scale can ensure that continuous infusions of sedatives such as propofol or lorazepam are titrated to a specific goal. Collaboratively, the critical care team must determine which level of sedation is most appropriate for each individual patient.¹

TABLE 9-1

SEDATION SCALES

SCORE	DESCRIPTION	DEFINITION
Riker Sedation-Agitation Scale (SAS)^*
7	Dangerously agitated	Pulls at endotracheal tube (ETT), tries to remove catheters, climbs over bed rail, strikes at staff, thrashes side to side
6	Very agitated	Does not calm despite frequent verbal reminding of limits, requires physical restraints, bites ETT
5	Agitated	Anxious or mildly agitated, attempts to sit up, calms down to verbal instructions
4	Calm and cooperative	Calm, awakens easily, follows commands
3	Sedated	Difficult to arouse, awakens to verbal stimuli or gentle shaking but drifts off again; follows simple commands
2	Very sedated	Arouses to physical stimuli but does not communicate or follow commands; may move spontaneously
1	Unarousable	Minimal or no response to noxious stimuli; does not communicate or follow commands
Motor Activity Assessment Scale (MAAS)^†
6	Dangerously agitated	No external stimulus required to elicit movement; is uncooperative, pulls at tubes or catheters, thrashes side to side, strikes at staff, tries to climb out of bed, does not calm down when asked
5	Agitated	No external stimulus required to elicit movement; attempts to sit up or move limbs out of bed, does not consistently follow commands (e.g., will lie down when asked but soon reverts back to attempts)
4	Restless and cooperative	No external stimulus required to elicit movement; picks at sheets or tubes or uncovers self; follows commands
3	Calm and cooperative	No external stimulus required to elicit movement; adjusts sheets or clothes purposefully; follows commands
2	Responsive to touch or name	Opens eyes, raises eyebrows, or turns head toward stimulus; or, moves limbs when touched or when name loudly spoken
1	Responsive only to noxious stimulus	Opens eyes, raises eyebrows, or turns head toward stimulus; or, moves limbs with noxious stimulus
0	Unresponsive	Does not move with noxious stimulus
Ramsey Scale^‡
1	Awake	Anxious; agitated and/or restless
2		Cooperative, oriented, and tranquil
3		Responds only to commands
4	Asleep	Brisk response to light glabellar tap or loud auditory stimulus
5		Sluggish response to light glabellar tap or loud auditory stimulus
6		No response to light glabellar tap or loud auditory stimulus
Richmond Agitation-Sedation Scale (RASS)^§,^¶
+4	Combative	Overtly combative, violent, immediate danger to staff
+3	Very agitated	Pulls or removes tube(s) or catheter(s); aggressive
+2	Agitated	Frequent nonpurposeful movement, fights ventilator
+1	Restless	Anxious but movements not aggressive or vigorous
0	Alert and calm
−1	Drowsy	Not fully alert, but has sustained awakening (eye-opening/eye contact) to voice (≥10 seconds)	} Verbal Stimulation
−2	Light sedation	Briefly awakens with eye contact to voice (<10 seconds)
−3	Moderate sedation	Movement or eye opening to voice (but no eye contact)
−4	Deep sedation	No response to voice, but movement or eye opening to physical stimulation	} Physical Stimulation
−5	Unresponsive	No response to voice or physical stimulation	} Physical Stimulation

^*Riker RR, et al: Prospective evaluation of the Sedation-Agitation Scale for adult critically ill patients, Crit Care Med 27(7):1325, 1999.

^†Devlin JW, et al: Motor Activity Assessment Scale: a valid and reliable sedation scale for use with mechanically ventilated patients in an adult surgical intensive care unit, Crit Care Med 27(7):1271, 1999.

^‡Ramsay MA, et al: Controlled sedation with alphaxalone-alphadolone, Br Med J 2(5920):656, 1974.

^§Sessler CN, et al: The Richmond Agitation-Sedation Scale: validity and reliability in adult intensive care unit patients, Am J Respir Crit Care Med 166(10):1338, 2002.

^¶Ely EW, et al: Monitoring sedation status over time in ICU patients: reliability and validity of the Richmond Agitation-Sedation Scale (RASS), JAMA 289(22):2983-2991, 2003.

The first step in assessing the agitated patient is to rule out any sensations of pain.¹ Clinical assessment is more challenging when the patient is obtunded or has an artificial airway in place. If the patient can communicate, the verbal pain scale of 0 to 10 is very useful. If the patient is intubated and cannot vocalize, pain assessment becomes considerably more complex. After medication for pain has been provided, the next step is to determine the minimum level of sedation required (Box 9-1). The SCCM guidelines recommend that all critically ill, intubated, mechanically ventilated patients have stated goals for analgesia and sedation¹ (Figure 9-1). The use of validated assessment scales is advised (see Table 9-1).

Box 9-1

Levels of Sedation

Light Sedation (Minimal Sedation, Anxiolysis)

Drug-induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected.

Moderate Sedation with Analgesia (Conscious Sedation, Procedural Sedation)

Drug-induced depression of consciousness during which patients respond purposefully to verbal commands, alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.

Deep Sedation and Analgesia

Drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully after repeated or painful stimulation. The ability to maintain ventilatory function independently is impaired. Patients require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.

General Anesthesia

Drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to maintain ventilatory function independently is impaired, and assistance to maintain a patent airway is required. Positive-pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired.

Data from Joint Commission on Accreditation of Healthcare Organizations: Comprehensive accreditation manual for hospitals, Oakbrook Terrace, Ill., 2000, The Joint Commission; and Jacobi J, et al: Clinical practice guidelines for the sustained use of sedatives and analgesics in the critically ill adult, Crit Care Med 30(1):119, 2002.

FIGURE 9-1 The algorithm provides guidelines for the use of analgesics and sedatives in mechanically ventilated patients. The text describes clinical and pharmacological issues that dictate optimal drug selection, recommended assessment scales, and precautions for patient monitoring. Doses are approximate for a 70-kg (154-pound) adult. *IVP,* intravenous push; Q, every; *PRN,* pro re nata (as needed). (From Jacobi J, et al: Clinical practice guidelines for the sustained use of sedatives and analgesics in the critically ill adult, *Crit Care Med* 30(1):119, 2002.)

Complications of Sedation

Oversedation is recognized as a state of unintended patient unresponsiveness in which the patient resides in a state of suspended animation resembling general anesthesia. Prolonged deep sedation is associated with significant complications of immobility, including pressure ulcers, thromboemboli, gastric ileus, nosocomial pneumonia, and delayed weaning from mechanical ventilation.

Too little sedation is equally hazardous. Most nurses have experienced the challenge of caring for a patient who unexpectedly removes the endotracheal or nasogastric tube. Unplanned extubation in restless, anxious, agitated patients occurs in 8% to 10% of intubated patients after an average of 3.5 days in the critical care unit. Six percent of self-extubation events cause significant complications, including aspiration, dysrhythmias, bronchospasm, and bradycardia.7

Pharmacological Management of Sedation

Several categories of sedatives are available. If the patient is experiencing pain, analgesia must be administered in addition to any sedative agents. Sedative agents include the benzodiazepines, sedative-hypnotic agents such as propofol, and the central alpha agonists (Table 9-2).¹

TABLE 9-2

PHARMACOLOGICAL MANAGEMENt: Sedation

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DRUGS	DOSAGE	ACTIONS	SPECIAL CONSIDERATIONS
Benzodiazepines
Diazepam	0.03-0.1 mg/kg every 0.5-6 hr (slow IV intermittent doses)	Anxiolysis Amnesia Sedation	Onset: 2-5 min after IV administration Side effects: hypotension, respiratory depression Half-life of parent compound: long (20-120 hr); active sedative metabolites also contribute to prolonged sedative effect Drug tolerance: physical tolerance develops with prolonged use, and higher dosage is required to achieve the same effect over time; slow wean required from diazepam after continuous prolonged use Phlebitis can occur with peripheral IV administration.
Lorazepam	0.02-0.06 mg/kg every 2-6 hr (slow IV intermittent doses)	Anxiolysis Amnesia Sedation	Onset: 5-20 min after IV administration Side effects: hypotension, respiratory depression Half-life of parent compound: relatively long (8-15 hr); sedative effect is also prolonged
	0.01-0.1 mg/kg/hr (continuous infusion)		Drug tolerance: physical tolerance develops with use, and higher drug dosage is required to achieve the same effect over time; slow wean required from lorazepam after continuous prolonged use Solvent-related acidosis and kidney failure can occur at high doses
Midazolam	0.02-0.08 mg/kg every 0.5-2 hr (slow IV intermittent doses)	Anxiolysis Amnesia Sedation	Onset: 2-5 min after IV administration Side effects: hypotension, respiratory depression Half-life of parent compound: 3-11 hr; sedative effect is prolonged when midazolam infusion has continued for many days, due to presence of active sedative metabolites; sedative effect is also prolonged in renal failure
	0.04-0.2 mg/kg/hr (continuous infusion)		Drug tolerance: physical tolerance develops with prolonged use, and higher drug dosage is required to achieve the same effect over time; slow wean required from midazolam after prolonged use
Sedative-Hypnotics
Propofol	5-80 mcg/kg/min (continuous infusion)	Anxiolysis Amnesia Sedation	Onset: very rapid onset (1-2 min) after IV administration Side effects: hypotension, respiratory depression (patient must be intubated and mechanically ventilated to eliminate this complication) Half-life of parent compound: 2-8 min when used as a short-term agent Sedative effect: range of 26-32 hr with prolonged continuous IV infusion; effective short-term anesthetic agent, useful for rapid “wake-up” of patients for assessment; if continuous infusion is used for many days, emergence from sedation can take hours or days; sedative effect depends on dose administered, depth of sedation, and length of time sedated Change IV infusion tubing every 12 hr Requires a dedicated IV catheter and tubing (do not mix with other drugs) Monitor serum triglyceride levels
Neuroleptic Agents
Haloperidol	0.03-0.15 mg/kg every 0.5-6 hr (IV intermittent doses)	Antipsychotic Antidelirium	Onset: 3-20 min after IV administration Half-life of parent compound: 18-54 hr Used in management of delirium; sedation is an unintended side effect
	0.04-0.15 mg/kg/hr (continuous infusion)