Table 1

 Characteristics of trials of 50% nitrous oxide for pain relief

StudyNo analysedParticipants*Pain sourceComparative interventionOutcomes assessed
AE, adverse effects; IM, intramuscular; IV, intravenous.
*Values are median (range) unless otherwise stated: †mean (SD); ‡mean (range); ¶median (interquartile range).
Castera et al, 20011510044.4 (12.5) years†Percutaneous liver biopsyPlacebo: oxygenAE: nausea, headache
60% male
Forbes and Collins, 20002210248 (19–80) yearsColonoscopyIV sedation: midazolam + meperidineRecovery
54% male
Triner et al, 1999192231 (8.9) years†MigrainePlacebo: 100% oxygenAE: vomiting, additional medication
14% male
Burton et al, 199817303.7 (1.6) years†Laceration repairPlacebo: 100% oxygenAE: vomiting, dizziness, oxygen desaturation
Notini-Gudmarsson et al, 1996103860 (29–83) yearsColonoscopyIM sedation: pethidineAE: nausea, dizziness, headache, oxygen desaturation
Recovery: beginning of procedure to discharge
Additional medication
Saunders et al, 1995169163.9 (53–75) years‡ColonoscopyPlacebo: oxygenAE: nausea, vomiting, dizziness, drowsiness, headache
63% male
Evans et al, 199513010 (4–15) yearsFracture reductionIM sedation: meperidine + promethazineAE: nausea, vomiting
63% maleRecovery: time in outpatient area
Saunders et al, 1994208946 (17–74) yearsColonoscopyPlacebo: airAE: hypotension, oxygen desaturation
43% maleIV sedation: midazolam + pethidineRecovery: Patient declared fit to leave department
Additional medication
Lindblom et al, 1994215043 (30–56)¶ColonoscopyIV sedation: ketobemidone + midazolamRecovery: Patient chose to leave recovery area
52% maleAdditional medication
Henderson et al, 199014165PaediatricVenous cannulationPlacebo: 100% oxygenAE: nausea, additional medication
Harrison et al, 198723170Adult womenLabourIM sedation: pethidine + promizine
Epidural: bupivacaine
Kerr et al, 1975188156 (31–72) yearsChest painPlacebo: airAE: vomiting, drowsiness
88% male