Effects of nitrous oxide on global and regional cortical blood flow.
Stroke September 1, 1990 DOI: 10.1161/01.str.21.9.1293 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational study Peer reviewed |
|---|---|
| Sample size | 12 |
| Population | Healthy volunteers |
| Dose | 25% and 50% N2O |
| Measures | xenon-133 clearance technique |
| Key findings | In 12 volunteers, 50% N2O increased global cortical blood flow by a mean of 37% above the 100% oxygen baseline, and 25% N2O produced a smaller but significant increase. Regional changes were heterogeneous, most often accentuating relative frontal blood flow, a pattern the authors argue differs from simple vasodilators like CO2 and may reflect N2O's differential effects on cerebral metabolism and the altered experiential state it produces. |
Abstract
We conducted regional cortical blood flow studies using the xenon-133 clearance technique on 12 volunteers during the administration of 25% and 50% N2O and during baseline conditions (breathing room air or 100% O2). Global cortical blood flow was very highly significantly increased above baseline measures in all subjects by 50% N2O (mean increase 37% above 100% O2 condition). A smaller but still significant increase was observed with 25% N2O. Analysis of regional cortical blood flow revealed heterogeneity in the pattern of changes; that is, the baseline pattern was altered by the inhalation of N2O, most often resulting in an accentuation of relative frontal blood flow. The anterior-posterior gradient in N2O-induced blood flow changes differs from that observed with simple vasodilatory agents, such as CO2, with which the increase is purely systemic and the baseline pattern is preserved. This indicates that N2O has differential effects on cerebral metabolism that may well reflect the typical alterations in experiential state reported by subjects.