Sedation in Critical Care

Sedation in Critical Care

Learning Objectives

This section details the reasons why sedation matters in critical care, emphasizing the following objectives:

  1. Patient Comfort: Essential in managing discomfort from painful procedures, invasive tubes, and sleep deprivation.

    • Aim is to alleviate pain and discomfort to improve patient quality of life during critical illness.

  2. Reduce Agitation: Focus on addressing fear, anxiety, and physiological stress in critically ill patients.

    • Recognizing the mental state of patients can significantly influence their recovery and rehabilitation outcomes.

  3. Avoid Oversedation: Achieving a balance between patient comfort and their ability to participate in mobility and rehabilitation goals.

    • Oversedation can lead to complications, lengthen hospital stays, and increase the risk of delirium.

Assessment Tools

Assessment of sedation levels in critically ill adults utilizes two validated scales:

  1. Richmond Agitation-Sedation Scale (RASS): This scale ranges from +4 (combative) to -5 (unresponsive).

    • Target: RASS 0, indicating patient is alert and calm.

  2. Sedation-Agitation Scale (SAS): Ranges from 1 (unarousable) to 7 (dangerously agitated).

    • Target: SAS 4, indicating the patient is calm and cooperative.

    • Light sedation is strongly recommended for mechanically ventilated patients to avoid complications.

RASS Scale Breakdown

The RASS scale classifies agitation and sedation levels:

  1. +4 to +1: Agitated states (combative, very agitated, restless).

  2. 0: Alert and calm (target sedation level, follows commands, maintains eye contact).

  3. -1 to -3: Light to moderate sedation (drowsy, briefly awakens, responds to voice).

  4. -4 to -5: Deep sedation (no response to voice, minimal response to physical stimulation).

Pain First

An essential guideline in managing agitation states is to rule out pain first in patients showing signs of agitation:

  1. For Verbal Patients: Use the 0-10 pain scale to evaluate pain intensity directly through communication about pain location and intensity.

  2. For Nonverbal/Intubated Patients: Use validated behavioral scales such as:

    • Behavioral Pain Scale (BPS)

    • Critical-Care Pain Observation Scale (CPOT)

    • Preemptive analgesia must be provided before performing any painful procedures to mitigate pain response.

Levels of Sedation

Different levels of sedation help categorize patients based on their responsiveness and need for airway management:

  1. Light Sedation (Minimal): Patient is alert and responsive to verbal commands (RASS 0 or -1 to +1, SAS 4).

  2. Moderate Sedation: Patient responds to verbal commands but does not require airway management (RASS -2 to -3, SAS 3-4).

  3. Deep Sedation: Patient cannot maintain their airway and is difficult to arouse (RASS -4 to -5, SAS 2).

  4. General Anesthesia: Patient is unarousable and requires airway support (RASS -5, SAS 1).

Medications - Sedative Medications

Current recommendations for sedative medications in mechanically ventilated adults include:

  1. Dexmedetomidine: An alpha agonist that provides sedation without causing respiratory depression.

  2. Propofol: A sedative-hypnotic agent notable for its rapid onset and short half-life, ideal for situations requiring quick patient awakening.

  3. Benzodiazepines: Generally not recommended due to associations with longer ventilation times and increased delirium risk.

Propofol: Key Facts

Characteristics:

  • Propofol is known for its white milky appearance and is packaged in glass containers.

  • Offers rapid onset of sedation within 30 to 60 seconds and a short half-life of 2 to 4 minutes initially.

  • It is particularly ideal for conducting awakening trials due to its short action.

Critical Nursing Actions:

  • Tubing must be changed every 12 hours.

  • Monitor serum triglycerides after 48 hours of administration due to the risk of complications.

  • Be vigilant for symptoms of propofol infusion syndrome as it is a known hazard.

  • Propofol is not an analgesic; thus, opioids should be added for pain management.

Complications - Propofol-Related Infusion Syndrome

A rare but critical complication associated with prolonged use of Propofol can occur with dosage exceeding 5 mg/kg/hr for more than 48 hours.

  • Signs & Symptoms:

    • Metabolic acidosis.

    • Rhabdomyolysis.

    • Acute kidney injury.

    • Cardiac dysrhythmias.

    • Mortality Rate: Approximately 50% if the condition goes unrecognized and untreated.

  • Management: Requires immediate recognition and intervention in the critical care setting, and monitoring of serum triglycerides is essential for patients on Propofol for more than 48 hours.

Understanding Dexmedetomidine

Benefits:

  • Offers a unique mechanism as an alpha-2 agonist, inhibiting the sympathetic nervous system which provides sedation and analgesia without causing respiratory depression.

  • Patients can potentially be extubated during the infusion, which is advantageous when weaning off mechanical ventilation.

  • Additionally, patients can maintain interaction while lightly sedated, aligning with modern sedation guidelines promoting patient engagement during recovery.

Best Practices in Sedation

  1. Daily Sedation Interruption: Conduct Spontaneous Awakening Trials (SAT) to prevent dependence on sedation and mitigate withdrawal symptoms.

    • 01 Stop Sedatives: Discontinue continuous infusions as per a scheduled protocol.

    • 02 Monitor Awakening: Assess consciousness using RASS/SAS and perform a neurological exam consecutively.

    • 03 Conduct Breathing Trials: Evaluate the patient’s readiness for extubation, if clinically appropriate.

    • 04 Restart at Lower Dose: Resume sedation at 50% of the previous dose, titrating to the target level while having protocols ready for immediate reinstitution of sedatives in cases of significant agitation.

Managing Agitation

Agitation can express itself through hyperactive movements ranging from restlessness to physical aggression:

  • Require assessment of causes, which may include pain, hypoxia, a full bladder, ventilator dyssynchrony, and delirium.

  • Use validated scales, such as RASS or SAS, to identify agitation as early as possible.

  • Treatment Approach: Address underlying issues to treat agitation effectively rather than resorting to overmedication. Benzodiazepines should be avoided due to their association with an increased incidence of delirium.

Understanding Delirium

Delirium represents a state of acute brain dysfunction affecting more than 50% of patients in critical care settings.

  • Definition: Characterized by global impairment of cognitive processes that arises suddenly, displaying symptoms such as disorientation and altered perceptions.

  • Clinical Note: It is crucial to note that not all delirious patients exhibit agitation; calm patients can also be experiencing delirium.

  • Serious Consequences: Increases length of hospital stay and mortality risk particularly in mechanically ventilated patients.

Delirium Assessment Tools

Two validated instruments that assess delirium in mechanically ventilated patients include:

  1. CAM-ICU (Confusion Assessment Method for ICU): Evaluates four features:

    • Acute change in mental status

    • Inattention

    • Disorganized thinking

    • Altered consciousness

  2. ICDSC (Intensive Care Delirium Screening Checklist): Includes eight items covering aspects like altered consciousness, inattention, disorientation, and hallucinations. Both tools can be effectively used with RASS to rule out patients who might be in a coma.

Prevention of Delirium

There are currently no medications that have proven efficacy in preventing delirium; thus, the focus must be on non-pharmacologic interventions:

  1. Early Mobility: Vital for preventing muscle weakness, which can exacerbate cognitive complications post-ICU.

  2. Sleep Protocols: Implement strategies such as dimming lights, reducing noise, clustering care activities, and providing earplugs or eye masks to facilitate better sleep for patients.

  3. Avoid Restraints: Use of physical restraints has been associated with the development of unpleasant memories in patients.

Delirium Prevention Bundle

An effective delirium prevention strategy includes:

  1. Light Sedation: Aim for the lightest level of sedation that is tolerable for the patient.

  2. Daily Awakening Trials: Implement spontaneous awakening trials each day.

  3. Breathing Trials: Evaluate the patients for readiness for extubation whenever indicated.

  4. Delirium Monitoring: Engage in daily screening using validated tools to monitor for signs of delirium.

  5. Early Mobility: Initiate and promote mobility in patients as soon as possible to enhance recovery.

Long-Term Impact

Post-ICU Syndrome (PICS): Characterized by both depression and cognitive decline following recovery from critical illness. Patient risk factors include:

  • Advanced age

  • History of prior cognitive impairment

  • Previous instances of delirium

  • Prolonged periods spent in critical illness.

  • Prevention Strategy: Employ the same interventions that aim to reduce delirium.

  • Patient Diaries: Encouraging written accounts by the healthcare team and family helps answer questions regarding the time spent unconscious, assisting in patient psychological recovery.

Special Population - Alcohol Withdrawal Syndrome

Critically ill patients with alcohol dependence are at risk for severe complications, with approximately 50% experiencing withdrawal symptoms. Interestingly, fewer than 5% may develop severe complications such as delirium tremens or seizures:

  • Assessment Tools:

    • AUDIT: Identifies alcohol dependence.

    • CIWA-Ar (Clinical Institute Withdrawal Assessment for Alcohol): Evaluates withdrawal severity to inform treatment.

  • Treatment Approach: Utilization of long-acting benzodiazepines (such as diazepam or lorazepam) and adjunctive medications as per established protocols.

Management of Delirium Tremens

Management of severe alcohol withdrawal necessitates a different approach compared to typical delirium:

  • Close Monitoring: Watch for escalating symptoms like agitation, tremor, anxiety, and sweating.

  • Symptom-Triggered Dosing: Utilize benzodiazepines guided by CIWA-Ar scores exceeding 10 to mitigate withdrawal symptoms effectively.

  • Thiamine Prophylaxis: Administer multivitamins including vitamin B1 to prevent neurologic damage resulting from withdrawal. It is crucial never to administer oral or IV alcohol as a treatment for alcohol withdrawal syndrome.

Teamwork in Collaborative Management

Successful sedation and management of critically ill patients necessitates shared responsibility across the healthcare team:

  1. Nursing: Involve continuous assessments, medication administration, and maintaining patient safety throughout care.

  2. Physicians: Formulate sedation goals and modify medications as required based on the patient’s response.

  3. Pharmacists: Responsible for optimizing medication regimens and monitoring for possible drug interactions.

  4. Rehabilitation: Early mobility initiatives are essential for preventing complications during recovery.

  5. Respiratory Therapy: Requires management of ventilators and conducting breathing trials as dictated by patient needs.

  6. Family Members: Provide a familiar presence that can greatly support the patient and may engage in care processes.