title: Effect of nitrous oxide in reducing pain of propofol injection in adult patients.
abstract: In a randomized, double-blind, prospective trial we compared the efficacy of pre-treatment with nitrous oxide (with or without premixed lignocaine in propofol) for the prevention of propofol-induced pain. Ninety consecutive patients were recruited in the study and divided into three groups of 30 each, who received either 50% nitrous oxide in oxygen along with lignocaine 40 mg mixed in 1% propofol 20 ml (Group NL), 50% nitrous oxide in oxygen without lignocaine in propofol (Group N), and 50% oxygen in air with lignocaine mixed in propofol 40 mg (Group L). Pain scores were graded on a four point verbal rating scale (0-3). Eighty-nine patients completed the study while one patient developed excitement, agitation and tremor during nitrous oxide in oxygen inhalation. Eleven patients (36.7%) complained of pain in the group L compared to 7 (23.3%), and 1 (3.3%), in groups N and NL respectively [group NL vs group L (P < 0.001) and group NL vs N (P < 0.001)]. There was no statistical difference observed between group N and group L. Inhalation of 50% nitrous oxide reduces pain on propofol injection. The combination of 50% nitrous oxide and lignocaine mixed with propofol was the most effective treatment.
authors.affiliation: Department of Anaesthesiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
authors.forename: P K
authors.initials: PK
authors.lastname: Sinha
authors.forename: P K
authors.initials: PK
authors.lastname: Neema
authors.forename: R C
authors.initials: RC
authors.lastname: Rathod
mesh_terms: D000328:Adult; D018685:Anesthetics, Inhalation / Q000627:therapeutic use*; D018686:Anesthetics, Intravenous / Q000009:adverse effects*; D000779:Anesthetics, Local; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007267:Injections / Q000009:adverse effects*; D008012:Lidocaine; D008297:Male; D009609:Nitrous Oxide / Q000627:therapeutic use*; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D015742:Propofol / Q000009:adverse effects*
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D008012:Lidocaine; D009609:Nitrous Oxide; D015742:Propofol