Summary of findings for the main comparison. What is the effect of general anaesthesia including nitrous oxide compared to without nitrous oxide on the risk of accidental awareness during general anaesthesia in patients aged five years and over?
| What is the effect of general anaesthesia including nitrous oxide compared to without nitrous oxide on the risk of accidental awareness during general anaesthesia in patients aged five years and over? | ||||||
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Patient or population: surgical patients Setting: Seven studies in Europe, three in North America, two in Japan, one in India, one in Hong Kong and one international multi centred Intervention: Nitrous oxide‐based Comparison: Nitrous oxide ‐free | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk without Nitrous oxide | Risk with Nitrous oxide | |||||
| Accidental awareness ‐ Overall (AAGA) assessed with: Any | Study population | not estimable | 3439 (14 RCTs) | ⊕⊝⊝⊝ VERY LOW 1 2 | Results not pooled due to rarity of events | |
| not pooled | not pooled | |||||
| Accidental awareness ‐ In recovery (AAGA) assessed with: Any | Study population | not estimable | 263 (5 RCTs) | ⊕⊝⊝⊝ VERY LOW 1 2 | Results not pooled due to rarity of events | |
| not pooled | not pooled | |||||
| Accidental awareness ‐ 24 hours (AAGA) assessed with: Any follow‐up: 1 days | Study population | not estimable | 556 (7 RCTs) | ⊕⊝⊝⊝ VERY LOW 1 2 | Results not pooled due to rarity of events | |
| not pooled | not pooled | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect | ||||||
1The anaesthetist delivering the anaesthetic was aware of the allocation in all studies, as this is essential for patient safety, so we rated all studies at high risk of performance bias.
2Due to the rarity of the events no pooling was appropriate.