In the nitrous oxide group,the puerperants deeply i nhaled the Nitrous oxide that premixed with oxygen(0 %∶0 %) times before uterus systoling 0 s,then loosed the pneusis device,and conducted the seco nd inhaling before uterus systoling by 0 s.
In the nitrous oxide group,the puerperants deeply i nhaled the Nitrous oxide that premixed with oxygen(0 %∶0 %) times before uterus systoling 0 s,then loosed the pneusis device,and conducted the seco nd inhaling before uterus systoling by 0 s.
再次宫缩前 ～ 0 s,再次吸入 ,如此反复 ,至胎儿娩出。