背景　周邊靜脈注射是臨床普遍的侵入性處置，當遭遇困難靜脈注射（以下簡稱困難靜注）問題時，將危及病人安全，增加護理人員壓力，耗用護理時數與衛材費用。目的　透過系統性文獻回顧暨統合分析，探討超音波導引於困難周邊靜脈注射病人之效應，及其在兒童與成人次族群的效應。方法　搜尋台灣期刊論文索引、華藝線上圖書館、CINAHL、Cochrane Library、PubMed/MEDLINE、ProQuest六個中英文資料庫，2016年4月以前之文獻，鍵入「超音波導引」與「周邊靜脈注射」等關鍵字，限制隨機控制試驗與臨床控制試驗的研究設計，共12篇文獻符合標準。依據Joanna BriggsInstitute嚴格評讀查核表，做研究方法之品質評估，並使用RevMan 5.3軟體進行統合分析。結果　超音波導引技術可顯著提升困難靜注病人的注射成功率（OR = 3.00, p ＜ .0001）與減少注射次數（MD= -0.61, p = .03）；次族群分析顯示，其可顯著提高困難靜注成人的注射成功率與減少注射次數，及顯著減少困難靜注兒童的注射時間。結論／實務應用　超音波導引技術可幫助健康照護專業人員透視周邊靜脈，提高靜脈注射成效。建議臨床可考量病人特性、超音波可近性、人員訓練可行性，適當運用超音波於提升周邊靜脈注射成效。

Background: Peripheral intravenous access is a common, invasive procedure that is performed in clinical practice. Difficult intravenous access may not only jeopardize patient safety but also increase staff stress, nursing hours, and material costs. Purpose: To explore the efficacy of ultrasound-guided peripheral intravenous access in difficult intravenous-access patients and in the two subgroups of adult patients and pediatric patients using systematic review and meta-analysis. Methods: Six Chinese and English databases, including the Index to Taiwan Periodical Literature System, Airiti Library, CINAHL, Cochrane Library, PubMed/MEDLINE, and ProQuest, were searched for related articles that were published between the earliest year available and April 2016. The search was limited to studies that used randomized control trials (RCTs) or controlled clinical trials (CCTs) and the associated key words ＂ultrasound-guided＂ AND ＂peripheral intravenous access＂. The 12 articles that met these criteria were used in the analysis. The Joanna Briggs Institute (JBI) critical appraisal checklist was used to assess methodological quality and RevMan 5.3 software was used to conduct the meta-analysis. Results: The ultrasound-guided technique was found to improve the success rate of intravenous access significantly (OR = 3.00, p ＜ .0001) and to decrease the number of attempts (MD = -0.61, p = .03) in the overall group of difficult intravenous-access patients. The subgroup analysis found a significantly improved success rate and decreased number of attempts in difficult intravenous-access adult patients and significantly decreased procedural times in difficult intravenous-access pediatric patients. Conclusions / Implications for Practice: The ultrasound-guided technique may improve the efficacy of intravenous access by helping health care professionals visualize the peripheral veins. We suggest that patient characteristics, ultrasound accessibility, and the feasibility of staff training be assessed in order to provide ultrasound guidance that improves the efficacy of intravenous access.