Sedation and Delirium



Fig. 27.1
Richmond Agitation-Sedation Scale (© Vanderbilt University)




Table 27.1
The ICU pain, agitation, and delirium care bundle





























Component

Pain

Agitation

Delirium

Assess

Assess ≥4×/shift and prn

 NRS if patient can report pain

 BPS or CPOT if patient cannot report

Assess ≥4×/shift and prn

 RASS or SAS if not paralyzed

 Brain function monitor if paralyzed

Assess delirium each shift and prn

 CAM-ICU or ICDSC

Treat

Treat pain then reassess

 Non-pharmacologic (relaxation)

 IV opioids +/− non-opioids for non-neuropathic pain

 Gabapentin or carbamazepine for neuropathic pain

Targeted sedation and/or daily SATs to achieve goal of RASS −1 to 0 or SAS 3 to 4

 If undersedated, use non-benzodiazepine sedatives as needed

 If oversedated, hold sedatives

Treat pain as needed

Reorient patients; provide eyeglasses, hearing aids as needed

Avoid benzodiazepines unless alcohol or benzodiazepine withdrawal

Avoid rivastigmine

Avoid antipsychotics if QTc is high

Prevent

Preprocedural analgesia

Relaxation therapy

Treat pain before using sedation

Consider daily SBTs and early mobility unless contraindicated

EEG if high ICP warrants burst suppression or high risk for seizures

Identify delirium risk factors

Avoid benzodiazepines

Early mobility

Promote sleep

Restart baseline psychiatric medications if indicated


This table modifies and summarizes the full bundle described in Barr et al. [4]

Abbreviations: BPS Behavioral Pain Scale, CAM-ICU Confusion Assessment Method for the Intensive Care Unit, CPOT Critical-Care Pain Observation Tool, EEG electroencephalogram, ICDSC Intensive Care Delirium Screening Checklist, ICP intracranial pressure, IV intravenous, NRS numeric rating scale, RASS Richmond Agitation-Sedation Scale, SAS Sedation Agitation Scale, SATs spontaneous awakening trials, SBTs spontaneous breathing trials


The SCCM guidelines (Table 27.1) also recommend monitoring ICU patients for delirium using one of two validated tools: the CAM-ICU [7] (Fig. 27.2; used in this case) or the Intensive Care Delirium Screening Checklist (ICDSC) [8]. Delirium, which is frequently hypoactive (i.e., characterized by somnolence rather than agitation) in the ICU, is easily overlooked when a validated assessment tool is not used. Use of the CAM-ICU or ICDSC, therefore, can improve detection and management of delirium.

A329322_1_En_27_Fig2_HTML.gif


Fig. 27.2
CAM-ICU (© 2002 Vanderbilt University)



Minimizing Sedation


Oversedation is common and harmful in the ICU, where heavily sedated patients remain on the ventilator longer and have higher mortality rates than their less sedated counterparts [9]. Patients who require sedatives during critical illness should therefore be managed with light rather than heavy sedation (barring a specific, time-limited indication for the latter, e.g., neuromuscular blockade, open abdomen, etc.). Use of a validated sedation scale (see section on “Sedative Choice”) is an important part of efforts to maintain light sedation, since frequent, reliable data regarding actual vs. targeted level of sedation can prompt changes in sedative choice, dose, and/or frequency. In addition to use of sedation scales, strategies that can improve outcomes by minimizing sedation include treating pain adequately before using sedatives [10], avoiding benzodiazepines in favor of other sedatives (e.g., propofol, dexmedetomidine, and/or an opioid) [11], using a sedation protocol [5], and interrupting sedatives on a daily basis with SATs [12, 13].


Risk Factors for Delirium


Though questions remain regarding the most effective strategies to prevent and treat delirium (see Prevention of Delirium and Antipsychotics sections), studies have identified a number of modifiable risk factors for delirium that should be addressed whenever possible when managing patients who are high risk as well as those already delirious. Numerous observational and interventional studies have found benzodiazepines (used initially in this case) increase delirium risk [14, 15], whereas dexmedetomidine does not [16, 17]. This may be because benzodiazepine pharmacokinetics make them prone to cause oversedation—drug-induced coma, regardless of which medication is the culprit, is a delirium risk factor—or because of their mechanism of action in the brain (GABA agonism). Infection, acute kidney injury, metabolic acidosis, mechanical ventilation, and high severity of illness are also risk factors for delirium that, in many cases, can be addressed [18].

In addition to the modifiable risk factors listed herein, many risk factors for delirium are not modifiable but an awareness of these factors may prompt clinicians to monitor high-risk patients more closely for delirium. These include advanced age and hypertension (both present in this case) as well as preexisting cognitive impairment, emergency surgery, and trauma.



Evidence Contour


This case highlights a number of evidence gaps and areas of controversy that remain despite the growing body of evidence regarding sedation and delirium in the ICU.


Sedative Choice


Dozens of randomized controlled trials have examined whether sedative choice affects outcomes in the ICU. Most compared a benzodiazepine (typically midazolam), the class of sedatives used most frequently in the ICU for several decades, with a non-benzodiazepine sedative, and the large majority of these trials found non-benzodiazepine sedation resulted in better outcomes (Table 27.2). A recent meta-analysis, in fact, found that benzodiazepine sedation (compared with sedation using propofol or dexmedetomidine) delays extubation and discharge from the ICU [11]. These data led the SCCM guidelines [4] to recommend non-benzodiazepines for sedation in the ICU, but questions remain regarding which drug(s) should be preferred. Dexmedetomidine has the benefit of facilitating light sedation and reducing delirium risk [16, 17], but costs remain high and the patient population that benefits the most from this agent has not yet been clearly defined. Propofol is less expensive than dexmedetomidine and less prone to cause oversedation than benzodiazepines but its use in some patients is limited by hemodynamic effects. Other drugs, including opioids, clonidine, haloperidol, and atypical antipsychotics are sometimes used to manage agitation in the ICU, but evidence of benefit in randomized trials is needed before use of these agents can be widely recommended.


Table 27.2
Randomized trials comparing benzodiazepines with alternative sedatives in the ICU







































































































































First author

Year

Population

Outcome(s) improved

Benzodiazepines vs. propofol

Trials finding better outcomes with propofol

Grounds RM

1987

Cardiac surgery

Faster awakening

Aitkenhead AR

1989

General ICU

More consistent awakening, faster weaning

McMurray TJ

1990

Cardiac surgery

Faster awakening

Carrasco G

1993

General ICU

More accurate sedation, faster awakening, lower costs

Roekaerts PM

1993

Cardiac surgery

Faster awakening, earlier extubation

Ronan KP

1995

Surgical ICU

Faster awakening

Sherry KM

1996

Cardiac surgery

Lower costs

Chamorro C

1996

General ICU

Better ventilator synchrony, faster awakening

Barrientos-Vega R

1997

General ICU

Earlier extubation

Weinbroum AA

1997

General ICU

Faster awakening

Sanchez-Izquierdo-Riera JA

1998

Trauma ICU

Faster awakening

McCollam JS

1999

Trauma ICU

Less oversedation

Hall RI

2001

Mixed ICU

More accurate sedation, earlier extubation

Carson SS

2006

Medical ICU

Fewer ventilator days

Trials finding no differences in outcomes

Searle NR

1997

Cardiac surgery

None

Kress JP

2000

Medical ICU

None

Huey-Ling L

2008

Cardiac surgery

None

Trials finding better outcomes with the benzodiazepine

None
     

Benzodiazepines vs. remifentanil

Trials finding better outcomes with remifentanil

Breen D

2005

Mixed ICU

Shorter duration of mechanical ventilation

Muellejans B

2006

Cardiac surgery

Earlier extubation and ICU discharge

Rozendaal FW

2009

Mixed ICU

Lighter sedation, shorter weaning time

Trials finding no differences in outcomes

None

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Jul 20, 2017 | Posted by in Uncategorized | Comments Off on Sedation and Delirium

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