Inhaled Analgesia for Pain Management in Labour

Summary

A Cochrane overview [Abstract] 1 included 15 Cochrane reviews (255 included trials) and 3 non-Cochrane reviews (55 included trials) of pain management in labour. Inhaled analgesia was compared with placebo or no treatment in 9 studies involving a total of 1495 women. Significantly fewer women in the inhaled analgesia group experienced severe pain compared with placebo or no treatment (RR 0.06, 95% CI 0.01 to 0.34; 2 trials, n=310). Pain intensity during the first stage of labour was significantly lower in the inhaled analgesia group (MD -3.50, 95% CI -3.75 to -3.25; 1 trial, n=509). There was no difference in assisted vaginal births (RR 1.50, 95% CI 0.44 to 5.15; 1 trial, n=200) or in caesarean sections (RR 1.20, 95% CI 0.75 to 1.91; 3 trials, n=465). Women receiving inhaled analgesia were more likely to experience vomiting (RR 9.05, 95% CI 1.18 to 69,32; 2 trials, n=619), nausea (RR 43.10, 95% CI 2.63 to 706.74; 1 trial, n=509), and dizziness (RR 113.98, 95% CI 7.09 to 1833.69; 1 trial, n=509). Flurane was more effective than nitrous oxide for pain relief (MD 13.87, 95% CI 4.02 to 23.72; 3 trials, n=123). However, there was no significant difference between nitrous oxid vs flurane in satisfaction with pain relief during the second stage of labour (proportion with good or excellent pain relief; RR 0.89, 95% CI 0.78 to 1.01; 4 trials, n=323).

A study 2 evaluated the effectiveness of pharmacological and non-pharmacological pain relief methods. 258 women were divided into 6 groups: epidural anaesthesia, water immersion and water birth, nitrous oxide, transcutaneous electrical nerve stimulation, multiple managemen, none. When comparing inhalation analgesia with placebo or no treatment, nitrous oxide was found to offer more pain relief. Labour pain intensity was less with epidural anaesthesia versus nitrous oxide gas during the first stage of labour (EA 5.90 [plusminus 2.91] vs. NO 6.30 [plusminus 2.42]) as well as during the second stage of labour (EA 7.10 [plusminus 2.34] vs. NO 8.95 [plusminus 1.52]).