Sedation, Analgesia, and Anesthesia Care
The sedation continuum
Minimal (anxiolysis), moderate (purposeful response to verbal/tactile stimulation), deep (purposeful response to repeated or painful stimulation), and general anesthesia. Sedation depth is a continuum - a patient intended for moderate sedation can slip into deep sedation. The nurse must be able to rescue a patient one level deeper than the intended level, which is why airway skills and capnography matter.
Agents and monitoring
- Benzodiazepines (midazolam) - anxiolysis/amnesia; reversed by flumazenil.
- Opioids (fentanyl) - analgesia; reversed by naloxone; cause respiratory depression and chest-wall rigidity with rapid dosing.
- Propofol - rapid onset/offset, hypotension and apnea.
- Ketamine - dissociative analgesia, preserves respiratory drive and reflexes but can cause laryngospasm, hypersalivation, emergence reactions.
- Dexmedetomidine - sedation without significant respiratory depression; bradycardia and hypotension.
Monitor level of consciousness, ventilation (capnography), oxygenation (pulse oximetry), and hemodynamics. Capnography detects hypoventilation and apnea before desaturation.
Local anesthetic limits and LAST
Lidocaine 4.5 mg/kg plain, 7 mg/kg with epinephrine; bupivacaine 2.5 mg/kg plain, 3 mg/kg with epinephrine. For local anesthetic systemic toxicity: stop injection, airway/oxygen, benzodiazepine for seizures, and 20% lipid emulsion 1.5 mL/kg bolus then infusion.
Traps
Assuming a patient who responds to voice is at moderate sedation; believing ketamine protects the airway absolutely; forgetting cumulative local anesthetic doses when multiple agents are mixed; ignoring that antagonist reversal shortens duration of the antagonist, not the agonist - patients must be observed for re-sedation.
Rule of thumb
Weight-based math first: a 70 kg patient gets a maximum of 315 mg plain lidocaine (4.5 × 70) or 490 mg with epinephrine.