Need for additional medication in patients receiving 50% nitrous oxide (N2O) compared with placebo or conventional analgesia
| Study | No of patients | Study population | Pain source | Additional medication(n (%)) | p value | |
|---|---|---|---|---|---|---|
| 50% N2O | Control | |||||
| 50% nitrous oxide v placebo | ||||||
| Triner et al, 199919 | 22 | Adult | Migraine headache | 2 (20) | 10 (83) | 0.008 |
| Saunders et al, 199420 | 60 | Adult | Colonoscopy | 3 (10) | 13 (43) | 0.007 |
| 50% nitrous oxide v conventional medication | ||||||
| Notini-Gudmarsson et al, 199610 | 38 | Adult | Colonoscopy | 0 (0) | 1 (5) | 0.31 |
| Saunders et al, 199420 | 59 | Adult | Colonoscopy | 3 (10) | 5 (17) | 0.47 |
| Lindblom et al, 199421 | 50 | Adult | Colonoscopy | 1 (4) | 5 (20) | 0.19 |
| Harrison et al, 198723 | 70 | Adult | Labour | 1 (5) | 40 (80) | <0.0001 |