生產疲憊之成長曲線及其預測因子

Abstract

疲憊不僅是盛行於生產過程常見的不適症，亦為干擾產婦調適產痛、第二產程用力、產後復舊以及承擔母性任務等能力的重要因素。是已知易影響其身心舒適，甚至是提高器械及剖腹產機率的產時健康問題。雖然如此，卻鮮少有研究針對此症狀進行整體性的探討，以致於截至目前為止，有關生產疲憊之科學實證性知識仍十分缺乏，而呈現疲憊隨生產動態歷程變遷之臨床研究更是闕如。這將有礙於處理生產疲憊問題之有效性，以及提升產時照護之品質。 基於此，本研究旨在描述疲憊隨生產進展之整體性發展（成長）趨勢，確認不同的生產疲憊成長曲線型態，並進一步探討不同生產疲憊成長曲線型態之生理、心理、情境預測因子，及不同疲憊型態對生產的影響。採前瞻、縱貫性設計（prospective, longitudinal design），以多元方法（包含實地觀察法、問卷調查、生理及物理測量），在自然的情境下，於所設定之時間架構内，系統性的收集產婦與疲憊相關的主客觀資料，以確實掌握研究變項隨產程不同時間點變遷的動態歷程。以中部某醫學中心預採陰道分娩方式生產的低危險待產婦為對象，共收集209名產婦資料。所收集之資料以 Multilevel Modeling 呈現生產疲憊隨時間進展之整體性變化，以及檢視樣本間成長曲線的變異性。以semiparameteric mixture model 區辨出研究對象不同型態之成長曲線。以邏輯式迴歸模式(logistic regression model)分析成長曲線型態與生理、心理、情境變項的關係。並依資料的類型，採Chi-square及t-test 檢定不同疲憊型態對生產的影響。 研究結果顯示，多數的產婦在進入產程時即伴隨著不等程度的疲憊，且以高疲憊佔大部份。疲憊程度隨著生產進展而逐漸增強，宮口開全時達到高峰。在變化曲線方面，以活動期之速率增加最為快速，產後初期則略為下降。本研究亦發現，生產疲憊的成長曲線包括了二種不同的型態：高疲憊組及低疲憊組。其中高疲憊組佔69.2%，低疲憊組佔30.8%。雖然二組的成長曲線皆隨時間進展而增加，但低疲憊組的成長速度相對的緩慢，這個次群體的產婦產後即刻的疲憊強度僅32.0。高疲憊組產婦的疲憊雖亦於產後略降，但仍維持相對高的強度。以單變項邏輯式迴歸模式進行影響因素之分析。結果顯示，胎次、入院時的乳酸值、睡眠、疼痛以及焦慮為影響生產疲憊不同成長曲線之生、心、情境因素。進一步將影響因素進行多變數邏輯式迴歸模式分析的結果則發現，胎次（OR: 4.86,p< 0.003）、入院時的乳酸值（OR: 4.57,p< 0.004）以及焦慮（OR: 26.59,p< 0.0001）為生產疲憊不同發展型態之預測因子。換言之，高疲憊組的初產婦入院時有高乳酸值以及顯著的高焦慮。在不同疲憊成長曲線型態對生產的影響方面，本研究對象無論是在產程時間長度、生產方式、使用止痛藥物以及子宮底壓迫次數與真空吸引的次數上皆未有顯著差異。而與產婦在生產過程的執行能力（performance）有關的產痛調適執行效能方面，二組只有在活動期早期呈現出顯著差異（P=0.02），尤其是在無法保持自我控制上，高疲憊組多於低疲憊組；而可配合家人或醫護人員指示方面，低疲憊組多於高疲憊組。至於在新生兒方面，二組在新生兒臍血中的乳酸值、1分鐘及5分鐘Apgar score方面亦均無顯著差異。 根據本研究之結果，在照顧待產中的婦女時，護理人員宜注意疲憊的累積效應，並致力於預防產婦在進入產程時即有高程度的疲憊，將產程一開始就有高疲憊的產婦列為優先處理之目標群體，特別是在疲憊快速增高的階段。由於焦慮在本研究中是顯著造成高疲憊的預測因子，因此減輕焦慮應有助於降低疲憊的累積。整體而言，本研究長時間於自然狀態下收集研究對象之主觀性資料、輔以客觀的生理指標，以針對生產疲憊問題進行系統性、實徵性的探討，並以先進的統計分析策略處理研究資料，進而發現過去研究所未呈現的結果；這些新知識將有助於進一步瞭解生產疲憊發展中的概念及特徵，不僅有利於深化理論的基礎，更有助於臨床護理人員在實際照顧產婦時，掌握關鍵時刻（critical time），提供適時（timing）照護，以更有效的控制產婦在生產過程中的疲憊問題。總之，本研究藉由臨床參與觀察、主客觀的測量以及適當的分析策略，整體性的探討生產過程的疲憊，研究結果除有助於護理科學知識之建構外，更可作為提升產時照護品質之參考。

Fatigue is not only a distressful symptom that is prevalent in childbirth; it also may interfere with a woman's ability to adjust to labor pain, to bear down in the second labor stage, hinder maternal recovery, and impair the assumption of the maternal role after birth. Fatigue is apt to cause physical and mental discomfort during labor, and increases the chances of medical intervention such as instrumental delivery and cesarean section. Despite these importance potential influences of labor to childbirth, little information exists on the actual effects of labor to the birth process. Empirical scientific knowledge related to childbirth fatigue is insufficient, especially concerning the lack of clinical research on maternal fatigue over time during labor. This lack of knowledge hinders the effectiveness in managing childbirth-related fatigue and in promoting the quality of intrapartum nursing care. Therefore, the purpose of the present research was to describe the childbirth-related fatigue trajectory throughout the labor process, identify the pattern of distinct fatigue trajectory, and determine the predictors of trajectory class membership and also on the influence of distinct fatigue patterns toward maternal performance and childbirth outcome. Under a natural setting, a prospective, longitudinal design and plurality methods (which included field observation, questionnaire, physiological and physical measurement) were taken to systematically collect both subjective and objective data. Obstetric low-risk women (n=209) were followed throughout their labor and delivery experiences. Longitudinal analyses on the repeated measures of fatigue were conducted using trajectory models (growth curve modeling). Predictors of trajectory class membership were identified in binary logistic regression. Chi-square and Student's t-test were used to examine the influence of distinct childbirth-related fatigue patterns toward maternal performance and childbirth outcome. The results showed when the women entered the labor process, they suffered from different level of fatigue, with most experiencing a high level of fatigue. The level of fatigue intensified with the progress of childbirth, reaching a peak that coincided with full dilation of the uterus. Fatigue increased in the active phase of labor and was somewhat reduced after birth. Considerable between-subject heterogeneity in individual trajectories over time were evident. Two trajectories of childbirth-related fatigue were identified: low intensity class (30.8%) and high intensity class (69.2%). The fatigue level of both classes intensified following the labor progress. Fatigue also increased most quickly during the active phase of labor, and remained high following delivery. Parity (OR: 4.86,p< 0.003), maternal blood lactate concentration at admission (OR: 4.57,p< 0.004), and anxiety(OR: 26.59,p< 0.0001) independently predicted the distinct trajectory pattern. Primiparas in the high fatigue intensity class experienced significantly more anxiety and higher lactate concentration at admission than the low intensity class. Regarding the influence of distinct fatigue pattern, the influences of the length of labor, the mode of delivery, in using analgesia, adopting fungus pressure or instrumental delivery were insignificant. Only the effective adaptation of labor pain at active stage displayed statistical significance (P=0.02), with the women in low intensity fatigue pattern more effectively adapting to their labor pain during the active stage than women in the high intensity fatigue class. There is also no statistical significance in the lactate acid and Apgar scores of newborns between the two fatigue trajectories. These findings suggest that there are critical points at which caregiver actions may have an effect on childbirth-related fatigue. The caregiver should endeavor to prevent a high level of fatigue once a woman enters the labor phase. Women who present with high fatigue at the onset of labor should be targeted for early intervention, especially in the period where fatigue increases rapidly. In this study, women with high levels of anxiety had a high risk of belonging to the high-fatigue intensity group. Accordingly, childbirth-related fatigue might be lessened if a woman’s anxiety could be alleviated. In general, this empirical research not only contributes to determining the critical time for dealing with childbirth-related fatigue, but also may contribute to a theoretical foundation that can be explored in further study, with the eventual goal of improving intrapartum care.