title: The efficacy and safety of intravenous emulsified isoflurane in rats.
abstract: Although direct IV injection of liquid volatile anesthetics is usually lethal, anesthesia using emulsified halothane and isoflurane without adverse effects has been safely induced in animals. We identified the safe concentration of emulsified volatile anesthetic preparations and determined the dose-response relationship of IV emulsified isoflurane and propofol in rats. Liquid/gas partition coefficients of desflurane, sevoflurane, isoflurane, enflurane, and halothane in 20% and 30% Intralipid were measured and used to calculate their saturated concentrations. Unsaturated emulsified isoflurane was prepared by adding liquid isoflurane to 30% Intralipid. The loss of forepaw righting reflex was taken as induction of anesthesia, and disappearance of electrocardiogram was taken as death. The median effective induction dose (ED50) and median lethal dose (LD50) of emulsified isoflurane were 0.072 and 0.216 mL/kg liquid isoflurane, respectively. The ED50 and LD50 of propofol were 5.89 mg/kg and 18.19 mg/kg, respectively. Time to return of forepaw righting reflex after injection of emulsified isoflurane (38 +/- 18 s) was significantly shorter than with propofol (101 +/- 62 s; P < 0.05). Anesthesia was successfully induced in rats by IV emulsified isoflurane with a comparable safety index and certain safety factor as propofol. Recovery of anesthesia after IV emulsified isoflurane was faster than with propofol.
authors.affiliation: Intensive Care Unit, Bejing Tiantan Hospital, Capital University of Medical Sciences, Bejing, China.
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Zhou
authors.forename: Nan-Fu
authors.initials: NF
authors.lastname: Luo
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Liang
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
mesh_terms: D000771:Anesthesia, Intravenous / Q000009:adverse effects / Q000379:methods; D018686:Anesthetics, Intravenous / Q000009:adverse effects; D000818:Animals; D004305:Dose-Response Relationship, Drug; D045703:Emulsifying Agents / Q000009:adverse effects; D005217:Fat Emulsions, Intravenous / Q000009:adverse effects; D005260:Female; D007530:Isoflurane / Q000009:adverse effects; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018686:Anesthetics, Intravenous; D045703:Emulsifying Agents; D005217:Fat Emulsions, Intravenous; D007530:Isoflurane