硬膜外減痛分娩效果不佳之相關因素

Abstract

研究目的: 產痛可能是女性一生中需經歷最痛的疼痛，嚴重的產痛可能產生許多潛在有害的生理反應，而目前用來解除產痛最有效且最沒有副作用的方式是硬膜上腔止痛。有很多研究探討產婦施行硬膜上腔止痛的安全性及優越性，但是非常少人討論與硬膜上腔止痛效果不佳有關的因素，在台灣也無人發表過相關的文章，而這跟改善產婦照護及產婦滿意度有相當大的關聯。因此，我們的研究希望了解目前臺北地區產婦施行硬膜上腔止痛的盛行率及硬膜上腔止痛的失敗率，並分析與硬膜上腔止痛效果不佳相關的因素。 過程與方法: 這是一個回溯性研究。我們蒐集了台北市新光吳火獅紀念醫院從2005年1月到2006年12月所有做硬膜上腔止痛的產婦的資料。我們從病歷、產科日誌及麻醉科紀錄中蒐集了產婦的基本資料、產程跟生產資料及疼痛處理的資料，所有產婦資料被分為兩組，訓練組(training group) 與確認組(validating group)。我們定義硬膜上腔止痛效果不佳為疼痛分數大於3，在給予硬膜上腔止痛藥物三十分鐘後。使用卡方檢定跟t檢定分析所有的變項，找出跟硬膜上腔止痛效果不佳相關的因素。有差異的變項再放入邏輯式回歸分析，試著建立預測模式。確認組的資料則用來確定此模型的準確度。 結果: 台北市新光吳火獅紀念醫院從2005年1月到2006年12月間共有5809位產婦生產，其中1015位接受了硬膜上腔減痛分娩，盛行率為17.47%。兩年中每個月的人數穩定。止痛效果不佳的比例為26%，此失敗組有較短時間的第一產程(310.7比264.43分鐘),給藥三十分鐘後子宮頸擴張程度較大(3.25比2.9公分)，子宮頸擴張速度較快(1.52比 0.67公分/小時)，較少使用產箝或真空吸引接生(11.25%比21.69%)，對減痛分娩較不滿意(21.77%比51.49% 表示非常滿意)。硬膜上腔止痛使用的藥物種類也有顯著差異，在失敗組較多產婦使用Lidocaine及Bupivacaine一次給藥，較多使用Bupivacaine持續給藥。邏輯式回歸分析建立的預測模型，選擇出有意義的變項為子宮頸擴張速度與使用的藥物種類，此預測模型的操作特性曲線下的面積(AUC, area under ROU curve)為0.6712。當可能性的切點為0.5時，確認組的準確度為0.6873。 結論: 這是台灣第一個分析產婦施行硬膜上腔減痛分娩效果不佳因素的研究。結果顯示跟硬膜上腔減痛分娩效果不佳相關的因素包括子宮頸擴張速度較快，使用Lidocaine或Bupivacaine一次給藥，使用Bupivacaine持續給藥。未來的研究可以加入更多的因子來分析。

Objectives: Labor pain is probably the most painful event in the life of a woman. There are many potential adverse physiological effects of severe labor pain. In recent years, epidural analgesia technique is the most effective and least depressant treatments for labor pain. Previous studies mostly focused on the safety and superiority of epidural analgesia than other techniques. Only very few discussed the factors related to the ineffectiveness of epidural painless labor. To improve patient care and the satisfaction of women in their labor and delivery experience continues to be one of the primary goals and challenges in obstetric analgesia services. In this study we expect to determine the prevalence of epidural analgesia for labor pain and failure rate in Taipei City. Then try to evaluate the factors associated with inadequate pain relief. Materials and Methods: We perform a retrospective chart review in parturients who underwent epidural analgesia for labor pain in Shin-Kong hospital in Taipei City, from January 2005 to December 2006. We retrieved each patient’s demographic characteristics, the course of labor and delivery, and the management of epidural analgesia from medical chart. All participants were divided into training group or validating group. Ineffectiveness of epidural analgesia of labor pain was defined as NRS > 3 at 30 minutes after epidural drug administration. We analyzed the data of the training group. Potential univariate correlated of ineffectiveness epidural analgesia were identified. Then forward stepwise logistic regression analysis was used to select significant ones that might predict the ineffectiveness of epidural painless labor. The ROC (receiver operating characteristic) curve by different cut-off points of this model was done. Then validating group was used to confirm the accuracy of this model. Results: A total of 1015 parturients received the epidural painless labor among the 5809 parturients who gave births during January 2005 to December 2006 in Shin-Kong hospital. The prevalence was 17.47%. The monthly utilization rates were stable in these two years. The failure rate of training group was 26%. The failure group has shorter duration of phase I (310.7 versus 264.43 minutes), more cervical dilatation in 30 minutes (3.25 versus 2.91 cm ), faster progression of cervical dilatation (1.52 versus 0.67 cm/per hour), less instrumentation delivery (11.25% versus 21.69%), and less satisfied (21.77% versus 51.49% pronounced very satisfied) about epidural painless labor. Epidural drugs resulted in significant different between two groups. The failure group used more Lidocaine and Bupivacaine then Ropivacaine as loading drug, and more Bupivacaine then Ropivacaine as continue drug. The predictive model of ineffectiveness epidural painless labor was established. Selective factors were cervical dilatation velocity, loading drugs, and continue drugs. The AUC (area under ROC curve) is calculated as 0.6712. When the cut point of probability is 0.5, the accuracy of validating group was 0.6873. Conclusions: This is the first study about the determinants of ineffectiveness epidural analgesia of labor pain in Taiwan. Our results revealed that factors associated with ineffectiveness of epidural analgesia of labor pain are faster cervical dilatation velocity, loading with Lidocaine or Bupivacaine and continue infusion with Bupivacaine. More factors to be concluded in analyses are suggested in further investigation.