Efficient intravenous access without distress: a double-blind randomized study of midazolam and nitrous oxide in children and adolescents

Arch Pediatr Adolesc Med. 2011 Sep;165(9):785-91. doi: 10.1001/archpediatrics.2011.56. Epub 2011 May 2.


Objective: To determine whether treatment with midazolam or with nitrous oxide is more efficient in facilitating intravenous (IV) access in lean and obese children and adolescents.

Design: A prospective, double-blind, randomized trial of 90 children and adolescents.

Setting: Astrid Lindgrens Children's Hospital, Karolinska University Hospital, Stockholm, Sweden. Patients A total of 60 obese children and adolescents and 30 growth-retarded children and adolescents, aged 5 to 18 years, with reported anxiety and/or difficulties with IV access.

Interventions: The patients were randomly assigned to receive midazolam (dose, 0.3 mg/kg; maximum dose, 15 mg), 50% nitrous oxide, or 10% nitrous oxide. All patients received lidocaine-prilocaine.

Main outcome measures: Efficiency, measured as total procedure time and number of attempts, which was defined as the number of attempts required to succeed in setting up 2 IV lines, with a successful procedure defined as 2 attempts for 2 IV lines. Secondary end points were patients' and parents' evaluations and procedure cancellations.

Results: Treatment with 50% nitrous oxide was the most efficient with regard to total procedure time (P < .001). An unfavorably long procedure time was observed after treatment with midazolam, especially in obese patients. An increased number of successful IV line procedures were obtained in the group of patients who received 50% nitrous oxide compared with the midazolam group and 10% nitrous oxide group (P = .04). The patients' evaluations were significantly more positive for 50% nitrous oxide than for both midazolam and 10% nitrous oxide, whereas no such difference was observed between midazolam and 10% nitrous oxide.

Conclusions: Compared with treatment with midazolam, treatment with 50% nitrous oxide during IV line procedures results in a shorter total procedure time, improved rate of IV access, and a better experience for the child or adolescent. Only under rare circumstances should obese children or adolescents be treated with midazolam because of the long procedure time.

Trial registrations: isrctn.org Identifier: ISRCTN33779750 and kctr.se Identifier: KCTR CT20090023.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Analgesics, Non-Narcotic / administration & dosage*
  • Anesthetics, Intravenous / administration & dosage*
  • Anesthetics, Local / administration & dosage
  • Chi-Square Distribution
  • Child
  • Child, Preschool
  • Conscious Sedation / methods*
  • Double-Blind Method
  • Endocrine System Diseases / complications*
  • Female
  • Humans
  • Male
  • Midazolam / administration & dosage*
  • Nitrous Oxide / administration & dosage*
  • Obesity / complications*
  • Prospective Studies
  • Statistics, Nonparametric
  • Time Factors
  • Treatment Outcome


  • Analgesics, Non-Narcotic
  • Anesthetics, Intravenous
  • Anesthetics, Local
  • Nitrous Oxide
  • Midazolam

Associated data

  • ISRCTN/ISRCTN33779750