22. (1.) Results by individual review ‐ inhaled analgesia.
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1. Inhaled analgesia for pain management in labour, 26 studies, 2967 women (Klomp 2012) | |||
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1.1. Inhaled analgesia versus placebo control/no treatment (9 studies, 1495 women) |
Outcome | No. of studies (no. women) | Results |
| Pain intensity during the first stage of labour (severe/extreme pain) | 2 (310) | Average RR 0.06, 95% CI 0.01 to 0.34, (random effects: heterogeneity: I2 = 51%, Tau2 = 1.08, Chi2 test for heterogeneity P =0.15), significantly fewer women in the inhaled analgesia group experienced severe pain | |
| Pain intensity during the first stage of labour (VAS 0‐10 after one hour) | 1 (509) | MD ‐3.50, 95% CI ‐3.75 to ‐3.25, mean pain score was significantly lower in the inhaled analgesia group | |
| Satisfaction with pain relief | Outcome not reported | ||
| Sense of control in labour | Outcome not reported | ||
| Satisfaction with childbirth experience | Outcome not reported | ||
| Effect on mother/baby interaction | Outcome not reported | ||
| Breastfeeding | Outcome not reported | ||
| Assisted vaginal birth | 1 (200) | RR 1.50, 95% CI 0.44 to 5.15, no evidence of a significant difference between groups | |
| Caesarean section | 3 (465) | RR 1.20, 95% CI 0.75 to 1.91, no evidence of a significant difference between groups | |
| Adverse effects for women (vomiting) | 2 (619) | RR 9.05, 95% CI 1.18 to 69.32, significantly more women in the inhaled analgesia group experienced vomiting | |
| Adverse effects for women (nausea) | 1 (509) | RR 43.10, 95% CI 2.63 to 706.74, significantly more women in the inhaled analgesia group experienced nausea (very wide CI) | |
| Adverse effects for women (dizziness) | 1 (509) | RR 113.98, 95% CI 7.09 to 1833.69, significantly more women in the inhaled analgesia group experienced dizziness (extremely wide CI) | |
| Adverse effects for women (drowsiness) | 1 (509) | RR 77.59, 95% CI 4.80 to 1254.96, significantly more women in the inhaled analgesia group experienced drowsiness (extremely wide CI) | |
| Adverse effects for infants (neonatal asphyxia) | 1 (110) | RR 1.11, 95% CI 0.26 to 4.73, no significant difference between groups | |
| Admission to special care baby unit/neonatal intensive care unit | Outcome not reported | ||
| Apgar score less than seven at five minutes | 1 (200) | RR 9.00, 95% CI 0.49 to 165.00, no significant difference between groups | |
| Poor infant outcomes at long‐term follow‐up | Outcome not reported | ||
| Cost | Outcome not reported | ||
| 1.2.1. Inhaled analgesia versus a different type of inhaled analgesia, nitrous oxide versus flurane (14 studies, 752 women) | Outcome | No. of studies (no. women) | Results |
| Pain intensity – pain score ‐VAS 0‐100 first stage of labour – where 100 is most severe pain |
3 (123) | Average mean difference MD 13.87, 95% CI 4.02 to 23.72, (random effects: heterogeneity: I2 = 64%, Tau2 = 47.26, Chi2 test for heterogeneity P =0.06), the mean pain score was significantly higher in the nitrous oxide group compared to the flurane group (flurane better pain relief) |
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| Pain intensity – pain relief score – VAS 0‐100, where 100 is the most pain relief | 2 (140) | Average mean difference MD ‐16.92, 95% CI ‐27.64 to ‐6.20, (random effects: heterogeneity: I2 = 70%, Tau2 = 42.58.80, Chi2 test for heterogeneity P =0.07), the mean pain relief score was significantly lower in the nitrous oxide group compared to the flurane group (flurane better pain relief) |
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| Satisfaction with pain relief during the first and second stages of labour (proportion with considerable or complete relief) | 2 (98) | RR 0.97, 95% CI 0.80 to 1.18, no significant difference between groups | |
| Satisfaction with pain relief during the second stage of labour (proportion with good or excellent pain relief) | 4 (323) | RR 0.89, 95% CI 0.78 to 1.01, no significant difference between groups | |
| Sense of control in labour | Outcome not reported | ||
| Satisfaction with childbirth experience | Outcome not reported | ||
| Effect on mother/baby interaction | Outcome not reported | ||
| Breastfeeding | Outcome not reported | ||
| Assisted vaginal birth | 5 (371) | RR 0.74, 95% CI 0.51 to 1.05, there were fewer assisted vaginal births in the nitrous oxide group, although this difference did not reach statistical significance | |
| Caesarean section | 1 (98) | Not estimable – no CS in either group | |
| Adverse effects for women (amnesia) | 4 (281) | Average RR 0.26, 95% CI 0.03 to 2.38, (random effects: heterogeneity: I2 = 74%, Tau2 = 2.76, Chi2 test for heterogeneity P =0.02), there was less amnesia reported in the nitrous oxide group, although this difference did not reach statistical significance | |
| Adverse effects for women (drowsiness) | 1 (80) | Not estimable – no drowsiness in either group | |
| Adverse effects for women (drowsiness), VAS 0‐100 mm | 2 (57) | MD ‐12.97, 95% CI ‐22.33 to ‐3.62, significantly lower mean drowsiness score with nitrous oxide compared to flurane group, (nitrous oxide better) | |
| Adverse effects for women (dizziness) | 2 (204) | RR 0.80, 95% CI 0.40 to 1.61, no evidence of a significant difference between groups | |
| Adverse effects for women (nausea) | 6 (378) | RR 3.30, 95% CI 1.64 to 6.63, significantly more women in the nitrous oxide group experienced nausea compared to the flurane group | |
| Adverse effects for women (vomiting) | 4 (261) | RR 2.66, 95% CI 1.06 to 6.70, significantly more women in the nitrous oxide group experienced vomiting compared to the flurane group | |
| Adverse effects for women (blood loss) | 2 (185) | MD 6.00, 95% CI ‐32.91 to 44.91, no significant difference between groups in blood loss | |
| Adverse effects for infants (neurologic and adaptive capacity score NACS <35 at 2 hours after delivery) | 3 (170) | RR 1.45, 95% CI 0.91 to 2.33, more babies in the nitrous oxide group had a NACS score of <35, although this difference did not reach statistical significance | |
| Admission to special care baby unit/neonatal intensive care | Outcome not reported | ||
| Apgar score less than seven at five minutes | 6 (409) | RR 0.22, 95% CI 0.01 to 4.47, no significant difference between groups (N.B. 5 of trials had no babies with Apgar score less than seven at five minutes) | |
| Poor infant outcomes at long‐term follow‐up | Outcome not reported | ||
| Cost | Outcome not reported | ||
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1.2.2. Inhaled analgesia of one strength versus a different strength (2 studies, 625 women) |
Outcome | No. of studies (no. women) | Results |
| Pain intensity | Outcome not reported | ||
| Satisfaction with pain relief during the first stage of labour (good to complete pain relief) | 1 (501) | RR 1.05, 95% CI 0.94 to 1.17, no significant difference between 50% and 70% nitrous oxide groups | |
| Satisfaction with pain relief during the second stage of labour (good to complete relief) | 1 (501) | RR 0.97, 95% CI 0.87 to 1.08, no significant difference between 50% and 70% nitrous oxide groups | |
| Sense of control in labour | Outcome not reported | ||
| Satisfaction with childbirth experience | Outcome not reported | ||
| Effect on mother/baby interaction | Outcome not reported | ||
| Breastfeeding | Outcome not reported | ||
| Assisted vaginal birth | 1 (501) | RR 0.83, 95% CI 0.61 to 1.14, fewer assisted vaginal births in the 50% nitrous oxide group, although this difference did not reach statistical significance | |
| Caesarean section | 1 (501) | RR 0.31, 95% CI 0.06 to 1.53, fewer caesarean sections in the 50% nitrous oxide group, although this difference did not reach statistical significance | |
| Adverse effects for women (vomiting) | 1 (501) | RR 1.29, 95% CI 0.86 to 1.94, less vomiting reported in the 70% nitrous oxide group, although this difference did not reach statistical significance | |
| Adverse effects for women (postpartum haemorrhage) | 1 (501) | RR 0.80, 95% CI 0.38 to 1.70, fewer women experienced postpartum haemorrhage in the 50% nitrous oxide group, although this difference did not reach statistical significance | |
| Adverse effects for women (hypoxaemia) | 1 (501) | RR 1.00, 95% CI 0.07 to 14.21, no significant difference between 50% and 70% nitrous oxide groups | |
| Adverse effects for infants | Outcome not reported | ||
| Admission to special care baby unit/neonatal intensive care unit | Outcome not reported | ||
| Apgar score less than seven at five minutes | Outcome not reported | ||
| Poor infant outcomes at long‐term follow‐up | Outcome not reported | ||
| Cost | Outcome not reported | ||
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1.2.3. Inhaled analgesia using one type of delivery system versus a different system (2 studies, 75 women) |
Outcome | No. of studies (no. women) | Results |
| Pain intensity | Outcome not reported | ||
| Nitrous oxide alone versus nitrous oxide with nasal supplement | Satisfaction with pain relief during the first stage of labour (considerable to complete pain relief) | 1 (42) | RR 1.18, 95% CI 0.94 to 1.48, no significant difference between groups |
| Sense of control in labour | Outcome not reported | ||
| Satisfaction with childbirth experience | Outcome not reported | ||
| Effect on mother/baby interaction | Outcome not reported | ||
| Breastfeeding | Outcome not reported | ||
| Assisted vaginal birth | Outcome not reported | ||
| Methoxyflurane using Penthrane Analgizer versus methoxyflurane using Cyprane inhaler | Caesarean section | 1 (26) | RR 2.60, 95% CI 0.12 to 58.48, no significant difference between groups |
| Nitrous oxide alone versus nitrous oxide with nasal supplement | Adverse effects for women (vomiting) | 1 (49) | RR 1.76, 95% CI 0.77 to 4.00, more vomiting reported in the nitrous oxide alone group, although this difference did not reach statistical significance |
| Methoxyflurane using Penthrane Analgizer versus methoxyflurane using Cyprane inhaler | Adverse effects for women (vomiting) | 1 (26) | Not estimable – no incidence of vomiting in either group |
| Analgizer versus methoxyflurane using Cyprane inhaler | Adverse effects for women (postpartum haemorrhage) | 1 (26) | RR 0.29, 95% CI 0.01 to 6.50, no significant difference between groups |
| Analgizer versus methoxyflurane using Cyprane inhaler | Adverse effects for women (mild pre‐eclampsia) | 1 (26) | RR 0.86, 95% CI 0.06 to 12.28, no significant difference between groups |
| Adverse effects for infants | Outcome not reported | ||
| Admission to special care baby unit/neonatal intensive care unit | Outcome not reported | ||
| Apgar score less than seven at five minutes | Outcome not in a suitable format (only reported mean and SD) | ||
| Poor infant outcomes at long‐term follow‐up | Outcome not reported | ||
| Cost | Outcome not reported | ||
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1.3. Inhaled analgesia versus TENS (1 study, 20 women) |
Outcome | No. of studies (no. women) | Results |
| Pain intensity during first stage of labour (moderate to severe) | 1 (19) | RR 1.10, 95% CI 0.84 to 1.45, no evidence of a significant difference between groups | |
| Satisfaction with pain relief | 1 (20) | RR 0.56, 95% CI 0.29 to 1.07, no evidence of a significant difference between groups | |
| Sense of control in labour | Outcome not reported | ||
| Satisfaction with childbirth experience | Outcome not reported | ||
| Effect (negative) on mother/baby interaction | Outcome not reported | ||
| Breastfeeding | Outcome not reported | ||
| Assisted vaginal birth | Outcome not reported | ||
| Caesarean section | Outcome not reported | ||
| Adverse effects for women and infants | Outcome not reported | ||
| Admission to special care baby unit/neonatal intensive care unit | Outcome not reported | ||
| Apgar score less than seven at five minutes | Outcome not reported in this format | ||
| Poor infant outcomes at long‐term follow‐up | Outcome not reported | ||
| Cost | Outcome not reported | ||
CI: confidence interval; RR: risk ratio