Arthurs G J, Rosen M
Anaesthesia. 1981 Apr;36(4):384-8. doi: 10.1111/j.1365-2044.1981.tb10243.x.
In six maternity hospital 516 mothers during labour received 50% nitrous oxide and 50% oxygen (Entonox) continuously at 5 litres/minute through a single-end nasal catheter and intermittently by a mouthpiece for a mean duration of 3 hours 30 minutes (513 mothers). A comparison was made with a control group of 575 mothers who had intermittent inhalation of Entonox only for a mean duration of 3 hours 6 minutes (574 mothers). The midwives had no difficulty learning to manage the administration of nasal Entonox. Eighty-six per cent of mothers agreed to use the nasal method and 70% continued for the duration of their labour. The midwives reported that pain relief was improved, and 51 (92%) would wish to continue offering the technique.
在六家妇产医院，516名产妇在分娩过程中通过单端鼻导管以每分钟5升的速度持续吸入50%氧化亚氮和50%氧气（恩托诺克斯），并通过口含器间歇性吸入，平均持续时间为3小时30分钟（513名产妇）。将其与一个由575名产妇组成的对照组进行比较，对照组产妇仅间歇性吸入恩托诺克斯，平均持续时间为3小时6分钟（574名产妇）。助产士学习管理鼻用恩托诺克斯的给药没有困难。86%的产妇同意使用鼻用方法，70%的产妇在整个分娩过程中持续使用。助产士报告说疼痛缓解情况有所改善，51名（92%）希望继续采用该技术。
