title: Nitrous oxide analgesia during retinopathy screening: a randomised controlled trial.
abstract: OBJECTIVE
  To determine if the addition of an inhaled equimolar mixture of nitrous oxide (N(2)O) and oxygen (EMONO) would produce superior pain relief to standard pharmacological and non-pharmacological measures during eye examination screening for retinopathy of prematurity (ROP) in premature infants.
  
  
  METHODS
  A randomised, double-blind controlled trial was conducted. Setting Royal Victoria Hospital, a tertiary neonatal intensive care unit in Montreal, Canada.
  
  
  METHODS
  Stable spontaneously breathing premature infants with birth weights less than 1500 g or gestation of 30 weeks and less.
  
  
  METHODS
  During the eye examination, all infants were swaddled, received oral sucrose and topical anaesthetics. Control group infants received a mixture of 50% oxygen and 50% nitrogen (n=18) administered by nasal cannula, while the intervention group received EMONO (50% oxygen and 50% N(2)O).
  
  
  METHODS
  Pain was assessed by the premature infant pain profile (PIPP).
  
  
  RESULTS
  The mean PIPP score at speculum insertion in the control group (8.4, 95% CI 7.6 to 9.3) was comparable with the EMONO group (8.5, 95% CI 7.3 to 9.8) with a p value of 0.94. There were no significant differences in heart rate or saturation between the two groups. EMONO inhalation was tolerated without any measured side effects.
  
  
  CONCLUSIONS
  EMONO does not produce any additional pain relief over currently used measures during ROP screening eye examinations. Systematically combining pharmacological and non-pharmacological treatment modalities appears to be the best option until newer treatments are proven effective.
authors.affiliation: Department of Pediatrics, Division of Neonatology, McGill University Health Centre, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, QC, Canada.
authors.forename: Romain
authors.initials: R
authors.lastname: Mandel
authors.forename: Nabeel
authors.initials: N
authors.lastname: Ali
authors.forename: John
authors.initials: J
authors.lastname: Chen
authors.forename: Ivan John
authors.initials: IJ
authors.lastname: Galic
authors.forename: Linda
authors.initials: L
authors.lastname: Levesque
mesh_terms: D000280:Administration, Inhalation; D000698:Analgesia / Q000379:methods; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage*; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007224:Infant Care / Q000379:methods; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D015997:Neonatal Screening / Q000009:adverse effects / Q000379:methods*; D009609:Nitrous Oxide / Q000008:administration & dosage*; D010100:Oxygen / Q000008:administration & dosage; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D010147:Pain Measurement / Q000379:methods; D012178:Retinopathy of Prematurity / Q000175:diagnosis*
chemical_list: D018712:Analgesics, Non-Narcotic; D004338:Drug Combinations; D009609:Nitrous Oxide; D010100:Oxygen