Rosen & Barkin's 5-Minute Emergency Medicine Consult (575 page)

Sedation Agents and Techniques

• Can be administered by various means
  
• Administer local or regional anesthesia if applicable.
  
• Perform the procedure.
  
• Closely observe and monitor patient during entire course of procedure as well as the recovery period afterward.
  
• Monitor patient until awake, alert, and back to baseline function.
  

DIAGNOSIS

Past medical history, anesthesia history, medications, allergies, review of systems and last meal.

• BP, heart rate, respiratory rate, pulse oximetry, cardiopulmonary and neurologic exams.
  
• Airway assessment:
  
  • Difficult bag-valve mask ventilation:
    
    • Beards
      
    • Abnormal facial contour
      
    • Morbid obesity
      
    • No teeth
      
    • Patients with COPD/asthma/congestive heart failure)
      
  • Difficult airway management:
    
    • Short neck
      
    • Large tongue
      
    • Small mandible
      
    • Mallampati scoring
      
    • Evidence of airway obstruction (stridor, drooling, and dysphagia).
      

TREATMENT

• Painful procedures:
  
  • Ketamine (± barbiturates [midazolam] to reduce emergence reactions)
    
  • Ketamine and propofol (ketofol)
    
  • Opiates (fentanyl/remifentanil) and midazolam
    
  • Nitrous oxide
    
  • Propofol and opiates (fentanyl)
    
  • Etomidate and opiates (fentanyl)
    
  • Dexmedetomidine
    
• Methohexital:
  
  • A short-acting barbiturate with rapid recovery that produces a state of unconsciousness and profound amnesia but has no analgesic properties
    
  • Dosage (IV): 0.75–1 mg/kg with subsequent titration at 0.5 mg/kg every 2 min to required effect
    
  • Onset: <1 min
    
  • Duration of action: 10 min
    
  • Side effects:
    
    • Respiratory depression with potential apnea
      
    • Hypotension due to myocardial depressant effect (caution with underlying myocardial disease)
      
• Pentobarbital:
  
  • A short-acting barbiturate used only for
    painless
    procedures as a sole agent for diagnostic modalities:
    
  • Dosage (IV): 2–5 mg/kg for children, and adults have a loading dose of 100 mg slow bolus repeated/titrated q3–5min to max. of 200–500 mg.
    
  • Dosage (IM): 4 mg/kg
    
  • Duration of action: 30–60 min
    
  • Onset: IV mode acts within 30 sec, and patient is appropriately sedated within 5 min.
    
  • Side effects: Central nervous system, respiratory depression, and bronchospasm (contraindicated in asthma/COPD)
    
• Benzodiazepines:
  
  • Commonly used for minimal sedation as it causes anxiolysis and amnesia
    
• Midazolam:
  
  • Short-acting agent that is lipophilic that allows penetration of the blood–brain barrier quickly
    
  • Provides anxiolysis and amnesia but not analgesia, so should not be the sole agent for painful procedures
    
  • Dosage (IV): 0.02–0.05 mg/kg (usual starting adult dose is 0.5–1 mg) with subsequent incremental doses at 3 min intervals to desired effect (single max. dose, 2.5 mg)
    
  • Dosage (IM): 0.05–0.2 mg/kg
    
  • Dosage (PO): 0.5–0.75 mg/kg (max. of 15 mg)
    
  • Dosage (nasal): 0.2–0.5 mg/kg (max. of 5 mg)
    
  • Onset/duration:
    
    • IV: Fairly rapid onset (1–2 min) and short duration of action (10–40 min)
      
    • IM, PO, and nasally: Slower onset and longer duration of action
      
  • Cautions for benzodiazepines:
    
    • Respiratory depression
      
    • Hypotension
      
    • Excessive sedation
      
    • Effects augmented by opioids, so reduce dose by 30–50% if opioid therapy utilized simultaneously
      
  • Effects may be reversed with flumazenil: 200 μg every 1–2 min, to effect
    
• Chloral hydrate:
  
  • To be used in procedural sedation in children (<2 yr old) undergoing painless diagnostic studies
    
  • Dosage (PO): 50–100 mg/kg with usual dose of 50–75 mg/kg (max. 2 g)
    
  • Dosage for rectal administration: Not recommended due to erratic absorption Max. dose 1 g in infants, 2 g noninfants
    
  • Onset: 30–45 min
    
  • Duration of action: 2–4 hr (effects can recur up to 24 hr)
    
  • Side effects:
    
    • Nausea and vomiting
      
    • Respiratory depression
      
    • Prolonged sedation
      
    • Rarely paradoxical excitation
      
• Dexmedetomidine: A short-acting, rapidly cleared α
  ₂
  -adrenergic agonist with sedative, anxiolytic, and analgesic properties:
  
  • Dosage IV: 1 μg/kg loading dose over 5–10 min followed by infusion at 0.2–1 μg/kg/h (use half dose for elderly or less invasive procedures)
    
  • Onset: Progressive during loading dose cycle
    
  • Duration: 6 min after cessation of infusion
    
  • Side effects:
    
    • Moderate BP and heart rate reductions should be expected, but alternative agent should be used if bradycardia and/or severe heart block.
      
• Etomidate: Unique class of sedative–hypnotic:
  
  • Produces amnesia and sedation but
    not
    analgesia
    
  • Minimal cardiovascular and respiratory effects
    
  • Dosage IV: 0.1–0.15 mg/kg
    
  • Onset: <1 min
    
  • Duration: 5 min
    
  • Side effects:
    
    • Myoclonus that seems to be related to dose and speed of administration
      
    • Nausea and vomiting
      
    • Hypotension and respiratory depression when combined with opioid or benzodiazepine
      
    • Adrenocortical suppression
      
• Ketamine
  
  • Produces analgesia, amnesia, and sedation due to its dissociative effect while maintaining spontaneous respirations and airway reflexes
    
  • Dosage (IV): 0.5–1 mg/kg (use midazolam 0.05 mg/kg and atropine 0.01 mg/kg concurrently) with onset of action 5–10 min
    
  • Dosage (IM): 2–4 mg/kg (combine atropine and midazolam in same syringe) with onset of action 15–25 min
    
  • Dosage (PO): 5–10 mg/kg (use midazolam 0.5 mg/kg and atropine 0.02 mg/kg PO as well) with onset of 30–45 min
    
  • Duration of action: IV 15–45 min; IM 30–90 min; PO 60–120 min
    
  • Side effects:
    
    • Hypertension and tachycardia
      
    • Increases intracranial and intraocular pressure
      
    • Stimulates salivary and tracheobronchial secretions
      
    • Emergence reactions with hallucinations reported, but are less frequent in children <10 yr; the incidence can be reduced by premedication with midazolam in adults.
      
• Nitrous oxide
  
  • Inhalational agent administered in 50% nitrous oxide/oxygen concentration:
    
  • Excellent agent for quick procedures, as it provides analgesia, anxiolysis, and sedation without the need for IV placement
    
  • Onset of action: 30–60 sec
    
  • Duration of action: 3–5 min after ceasing inhalation
    
  • Side effects are rare but can cause deep sedation with respiratory depression (especially if concurrent narcotic) as well as nausea and vomiting.
    
  • Contraindications: Pregnancy, pneumothorax, and bowel obstruction
    
• Fentanyl
  
  • Ultra-short acting synthetic opioid
    
  • Analgesic properties but minimal sedative and no amnestic properties
    
  • Dosage (IV): 1–4 μg/kg (titrate)
    
  • Onset (IV): 30–60 sec with peak at 1–3 min
    
  • Transmucosal 10–15 μg/kg with onset in 15–20 min:
    
    • Oral lozenge (Oralet) allows patient to suck on drug, which then can be removed by physician or patient when adequate sedation achieved.
      
  • Duration of action: 30 min
    
• Remifentanil
  
  • Potent ultra-shorting synthetic with potent sedative and analgesic properties.
    
  • Dosage (IV): 0.5-1 μg/kg every 2 min titrated to effect
    
  • Onset (IV): <1 min
    
  • Duration of action: 5 min
    
  • Side effects of fentanyl and remifentanil:
    
    • Respiratory depression with potential apnea
      
    • Hypotension
      
    • Chest wall rigidity is a rare complication when large doses given quickly.
      
    • Use <1/3 dose in children <6 mo.
      
    • Emesis with transmucosal preparation
      
• Propofol: Rapid onset and short duration make for excellent ED agent for procedural sedation:
  
  • Produces amnesia and sedation but
    not
    analgesia
    
  • Onset of action: 15–45 sec
    
  • Dosage (IV): 0.5–1 mg/kg bolus (usually given as 20 mg boluses every 10 sec in adults until desired effect is obtained) followed by infusion of 50–75 μg/kg/min; effective total dose for adults 20–150 mg
    
  • Duration of action: <2 min
    
  • Side effects:
    
    • Dose-related respiratory depression with occasional apnea (care with COPD)
      
    • Hypotension (care with cardiomyopathy or hypovolemia)
      
    • Pain at injection site
      
  • Care with patients in renal failure due to accumulation of active metabolite leading to prolonged sedation
    

• Naloxone: Opioid antagonist:
  
  • For reversal of respiratory depression, apnea, and severe hypotension
    
  • Dosage: 0.1–0.2 mg/kg IV/IM in incremental doses (to total of 2 mg) q1–2min to the desired reversal effect; usual adult dose of 1–2 mg effective
    
  • Duration of action: 20–45 min