李季 陳小蘭 張效銘 李洋平 馬峰 柏明
[摘要]急性腎損傷(AKI)是危重癥患者的常見并發(fā)癥之一。近年來需要腎臟替代治療(RRT)的AKI患者發(fā)病率顯著升高。對于血液動力學不穩(wěn)定的患者,連續(xù)腎臟替代治療(CRRT)是最常用的RRT模式。目前,雖有一些臨床研究對CRRT治療的適應證、開始和停止治療的時機進行了深入探討,但在一些結(jié)果上仍存在較大爭議。本文就危重癥患者使用CRRT治療的適應證、開始和停止治療的時機等方面的研究進展作一綜述,以期為CRRT相關的臨床工作和臨床研究提供重要信息。
[關鍵詞]急性腎損傷;連續(xù)腎臟替代治療;適應證;危重癥
[中圖分類號] R692.5? ? ? ? ? [文獻標識碼] A? ? ? ? ? [文章編號] 1674-4721(2019)9(c)-0022-04
[Abstract] Acute kidney injury (AKI) is one of the common complications of critically ill patients. The incidence rate of AKI patients requiring renal replacement therapy (RRT) has increased significantly in recent years. For patients with hemodynamic instability, continuous renal replacement therapy (CRRT) is the most commonly used RRT mode. At present, although some clinical studies have conducted in-depth discussions on the treatment indications and timing of initiation and discontinuation for CRRT, there are still some controversies on some results. This article reviews the research advances of treatment indications timing of initiation and discontinuation for CRRT in critically ill patients, so as to provide important information for clinical work and clinical research related to CRRT.
[Key words] Acute kidney injury; Continuous renal replacement therapy; Indications; Critically ill
急性腎損傷(acute kidney injury,AKI)是危重患者常見的并發(fā)癥,5%~10%的AKI患者在ICU期間需要接受腎臟替代治療(renal replacement therapy,RRT)[1],接受RRT的重癥AKI患者住院期間死亡率可達30%~70%[2]。在過去的20年中,需要RRT的AKI發(fā)病率每年增加約10%[3]。常用的RRT模式包括連續(xù)腎臟替代治療(continuous renal replacement therapy,CRRT)、常規(guī)間歇性血液透析(conventional intermittent hemodialysis,IHD)和延長的間歇性腎替代療法。RRT應用的許多方面仍然存在爭議,包括其適應證、開始和停止的最佳時機等。重癥患者多合并血液動力學不穩(wěn)定,CRRT是首選模式。本文就危重癥患者使用CRRT治療的適應證、開始和停止治療的時機等方面的研究進展作一綜述,以期為CRRT相關的臨床工作和臨床研究提供參考依據(jù)。
1 CRRT適應證
CRRT適應證與常規(guī)RRT的適應證類似,包括容量超負荷、嚴重的代酸和電解質(zhì)紊亂(高鉀、低鈉、高鈉、高磷血癥)、尿毒癥(尿毒癥腦病、心包炎等)以及持續(xù)/進展型AKI[1]。每個適應證均包含較廣泛的內(nèi)容和范圍,應當作半客觀指標。
1.1容量超負荷
由于AKI患者腎臟調(diào)節(jié)容量平衡的能力受損,且常需使用較多的靜脈液體、血液制品,較易出現(xiàn)容量超負荷。臨床上,容量超負荷導致器官功能受損且利尿劑無效時,需開始RRT治療。雖然,兒童和成人開始RRT時容量負荷的嚴重程度與死亡風險之間存在很強的相關性,但其因果關系仍未明確。患者基礎疾病的嚴重程度、容量負荷發(fā)展速度與患者預后之間存在復雜的相互作用[4-5]。目前,還無前瞻性數(shù)據(jù)明確在何種容量負荷閾值時采用RRT進行超濾能降低患者死亡率。
1.2酸堿失衡
腎衰竭患者常伴隨腎臟泌酸能力的受損,因此常常出現(xiàn)進行性代謝性酸中毒[6]。對于某些嚴重酸中毒且難以接受常規(guī)糾酸治療的患者,間歇性或連續(xù)性RRT均能給患者帶來顯著收益[7]。通常當pH<7.1~7.2或血碳酸氫鹽水平<12~15 mmol/L時開始RRT治療。代謝和呼吸性酸中毒同時出現(xiàn)時常易導致嚴重酸中毒,危及患者生命。對于接受機械通氣的急性肺損傷患者,可能需要更早開始RRT。盡管RRT能有效清除乳酸,但很少有證據(jù)證實通過RRT增加乳酸清除后能顯著改善藥物中毒(如二甲雙胍)之外的乳酸酸中毒患者的臨床預后。
1.3嚴重電解質(zhì)紊亂
多種電解質(zhì)紊亂與AKI密切相關。嚴重的高鉀血癥最易危及患者生命,需及時糾正以預防心臟毒性和心律失常。當高鉀血癥經(jīng)藥物治療無效或在緩解后快速復發(fā)時需進行RRT治療。血鉀水平<6 mmol/L時,很少僅為了治療高鉀血癥而開始RRT。如經(jīng)保守治療且血鉀仍>6.5 mmol/L則需開始RRT。一方面,IHD可以更快地糾正高鉀血癥,可作為首選治療模式;另一方面,雖然CRRT降低血鉀的速率相對緩慢,但可以較好將血鉀維持在相對穩(wěn)定的水平。其他AKI可能伴隨的電解質(zhì)異常,如嚴重低鈉血癥、高鈉血癥和高磷血癥,也應作為啟動RRT的一個重要因素進行考慮[6]。在伴有嚴重低鈉或高鈉血癥的AKI患者中,與IHD相比,CRRT可以緩慢、可控地升高或降低血鈉濃度,這對于防止患者出現(xiàn)滲透性脫髓鞘相關的神經(jīng)系統(tǒng)后遺癥非常重要[6,8]。
4 RRT治療與否的倫理問題
在AKI患者中,由于AKI患者死亡率很高,開始或停止RRT也會面臨一些臨床和倫理之間的矛盾。在與患者和/或其家人/監(jiān)護人探討開始和停止RRT治療時,應綜合考慮患者的整體預后、治療目標以及其他生命支持治療的情況[25],并及早開始姑息治療。另一方面,患者預后不確定時或患者及家屬/監(jiān)護人未最終決定開始/停止RRT及其他生命支持治療時,限制治療時間原則是一種有效的應對策略[26]。
5小結(jié)
CRRT已成為重癥AKI患者治療的主要手段。對于無RRT急診適應證的患者,開始RRT的最佳時機仍存在爭議,需進一步研究進行探討,以實現(xiàn)對患者的個體化指導。在決定開始和停止CRRT時,應綜合考慮患者的整體預后、總體治療目標以及其他生命支持治療的使用情況。
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(收稿日期:2019-04-08? 本文編輯:任秀蘭)