Sedation and Train of Four
Commonly Used Sedatives
"Standard" sedation -Benzodiazepines - midazolam, lorazepam, diazepam -Anesthetics - propofol Special circumstance sedation -Central alpha-agonists - clonidine, dexmedetomidine (Precedex) -High-dose opioids: fentanyl, hydromorphone, morphine -Haloperidol
Assessment of Agitation--Hyperactive psychomotor functions
-Tachycardia -Hypertension -Movement
Train of Four Monitoring
A peripheral nerve stimulator, also known as a train-of-four monitor, is used to assess neuromuscular transmission when neuromuscular blocking agents (NMBAs) are given to block musculoskeletal activity Peripheral nerve stimulation is most commonly used for ongoing monitoring in the intensive care unit (ICU).
Consequences of Suboptimal Sedation: Inadequate sedation/analgesia
Anxiety Pain Patient-ventilator dyssynchrony Agitation Self-removal of tubes/catheters Care provider assault Myocardial ischemia Family dissatisfaction
Continuous Monitoring of Sedation
Assess brain activity -Electroencephalogram (EEG) -Bispectral Index [BIS]) Application of EEG to bedside -Bispectral Index Score (BIS) -Patient State Index (PSI) Interpretation of values -Values 0 (flat EEG) to 100 (awake) -40 to 60 deep sedation plus amnesia
Neuromuscular blocking agents
NMBAs are used to decrease the work of breathing and facilitate mechanical ventilation in the most critically ill patients --Pancuronium (Norcuron) They lack anesthetic, analgesic, and sedation properties Can be given as a bolus or as a drip They paralyze all of the muscles of the patient No respiratory muscles work The use of NMBAs has been decreasing because of their side effects of prolonged paralysis and muscle weakness (can even be permanent) However, in severe cases when sedation and analgesia have been maximized, NMBAs may still be used in conjunction with other agents for several indications, such as to control patients respirations with the use of certain ventilators and to decrease oxygen consumption
Management—Sedatives
Pharmacological treatment for anxiety -Benzodiazepines -Propofol -Dexmedetomidine Titrate to an end point (sedation scales or tools) •Goal is to use less sedation by titrating to sedation targets (use of a scale).
Consequences of Suboptimal Sedation: Excessive sedation
Prolonged mechanical ventilation --Tracheostomy --DVT, VAP --Failure to initiate spontaneous breathing trials Increased ICU LOS --Added cost Impede assessment of neurologic function Increase risk for delirium Inability to communicate
Sedation Assessment—Tools
Sedation medication is given to reduce symptoms; dose is adjusted based on tools or scales Interobserver agreement in assessment using various scales is important
train of four stimulation
The 2 electrodes are placed over the path of the ulnar nerve The expected response is to see the thumb twitching -Number of normal twitches would be 4 -You titrate the NMBA depending on how deep you wish the paralization and the number of thumb twitches the TOF elicits -You NEVER want 0 twitches
Richmond Agitation-Sedation Scale (RASS)
The RASS is a 10-point scale, from 4 (combative) through 0 (calm, alert) to -5 (unarousable). The patient is assessed for 30 to 60 seconds in three steps, using discrete criteria
Sedation-Agitation Scale (SAS; Riker)
The Sedation-Agitation Scale describes patient behaviors seen in the continuum of sedation to agitation. Scores range from 1 (unarousable) to 7 (dangerously agitated).
