PSA using etomidate IV etomidate: Titrate doses to patient response (deep sedation), as follows: Initial dose: 0.1 to 0.15 mg / kg IV Subsequent doses: 0.05 mg / kg IV every 3 to 5 minutes PSA using ketamine Before and during the initial ketamine dose, converse with the patient about a happy or joyful topic (eg, a favorite person, place, or activity).