What are the signs of sedation?

Signs of Sedation

The key signs of sedation exist on a continuum from minimal to deep sedation, assessed primarily by responsiveness to stimulation, airway patency, adequacy of spontaneous ventilation, and cardiovascular stability. 1

Clinical Assessment Framework

The level of sedation is determined by a stimulus-response relationship: how the patient responds to verbal cues, light tactile stimuli, or painful stimulation. 1 This assessment must be documented continuously throughout sedation and recovery. 1

Levels of Sedation and Their Signs

Minimal Sedation (Anxiolysis):

• Normal response to verbal stimulation 1
• Cognitive function and coordination may be impaired 1
• Airway, ventilation, and cardiovascular function remain unaffected 1

Moderate Sedation (Conscious Sedation):

• Purposeful response to verbal commands alone or with light tactile stimulation 1
• Patient remains awake and cooperative on demand 2
• No airway intervention required 1
• Spontaneous ventilation remains adequate 1
• Cardiovascular function usually maintained 1

Deep Sedation:

• Purposeful response only after repeated or painful stimulation 1
• Patient cannot be easily aroused 1
• Airway intervention may be required 1
• Spontaneous ventilation may be inadequate 1
• Cardiovascular function usually maintained 1

General Anesthesia:

• Unarousable, even with painful stimulus 1
• Airway intervention often required 1
• Spontaneous ventilation frequently inadequate 1
• Cardiovascular function may be impaired 1

Observable Clinical Signs

Consciousness and Responsiveness

• Level of alertness: ranging from lethargic response to name spoken in normal tone, to requiring loud/repeated calling, to requiring physical prodding or shaking, to complete unresponsiveness 1
• Ability to follow simple commands while appearing awake or asleep 3
• Fluctuating levels of consciousness throughout the day 4

Sedative Effects on Behavior

• Sleepiness or drowsiness (most common and reliable marker) 5, 3
• Occasional drowsiness progressing to somnolence 5
• Decreased psychomotor and cognitive performance 6
• Amnesia for perioperative events, optimum within 2 hours of intramuscular administration or 15-20 minutes after intravenous injection 3

Respiratory Signs

• Respiratory rate changes (must be monitored continuously) 1
• Hypoventilation or airway obstruction 1
• Oxygen desaturation 1
• Apnea 1
• Upper airway obstruction (particularly when excessively sleepy and difficult to arouse) 3

Cardiovascular Signs

• Bradycardia and/or hypotension may indicate oversedation 1
• Heart rate and blood pressure changes (baseline tachycardia and hypotension may indicate volume depletion rather than sedation) 1
• Conversely, tachycardia and hypertension may indicate inadequate sedation 1

Motor and Coordination Signs

• Impaired visual tracking (ability to keep a moving line centered) lasting up to 8 hours after intramuscular administration 3
• Unsteadiness 3
• Enhanced sensitivity to CNS-depressant effects of alcohol and other drugs 3

Critical Monitoring Parameters

Vital signs must be documented:

• Heart rate 1
• Blood pressure (baseline before sedation, then at 3-5 minute intervals) 1
• Respiratory rate 1
• Oxygen saturation 1
• Expired carbon dioxide values 1
• Temperature 1

Sedation scoring systems should be used to track level of consciousness at appropriate intervals during and after sedation. 1, 5

Important Caveats

Paradoxical Reactions

Some patients may experience paradoxical stimulation rather than sedation, including agitation, involuntary movements, hyperactivity, and combativeness. 7, 5 These reactions have been reported in both adult and pediatric patients and require caution before continuing sedation. 7

Sedation as a Continuum

Because sedation exists on a continuum, patients may move easily from light to deep sedation with potential loss of protective reflexes. 7 This is especially true in pediatric patients. 7 Practitioners must be able to rescue patients whose sedation level becomes deeper than intended. 1

High-Risk Populations

• Children with severe obstructive sleep apnea who have experienced repeated desaturation episodes will have altered opioid receptors and require lower titrated doses. 1
• Older patients require lower doses and have unpredictable responses, with up to four-fold differences in opioid requirements compared to younger patients. 5
• Obese patients should have most drug doses adjusted to ideal body weight rather than actual weight. 1

Prolonged Effects

Excessive sleepiness and prolonged lack of recall can occur with greater than recommended doses or with long half-life medications (chloral hydrate, intramuscular pentobarbital, phenothiazines). 3, 1 This poses particular risk for infants and toddlers in car safety seats due to potential airway obstruction from head position. 1