在末期腎臟疾病患者中，多數依靠自體瘻管（AVF）來進行血液透析（HD），以替代腎臟功能。然而，AVF時常會出現狹窄的症狀。如果未能時刻監測AVF的通暢性，狹窄有惡化成血栓或動靜脈瘤等併發症的風險，最終導致AVF阻塞，嚴重影響透析進行。臨床上通常使用超音波或血管造影來評估AVF的狹窄程度（DOS），但這些方法僅限於醫院或診所內。且根據文獻，目前臨床上仍缺乏合適的居家監測設備，讓HD患者能自我評估AVF的狹窄情形。有鑒於此，本研究提出一套居家瘻管照護系統，幫助HD患者能自行測量AVF的流通情形，從而避免阻塞發生。該系統能同步量測心電圖（ECG）和雙手光體積變化描計圖（PPG）訊號，並傳輸至手機app中。此app整合了即時訊號顯示、峰值特徵偵測和有效脈波傳遞時間（PTT）計算等演算法，用於評估DOS。此研究藉由ECG與雙手PPG計算雙側PTT的差值，分析DOS。先前研究已證實，雙側PTT的不對稱性與DOS有高度相關性，因為狹窄會增加血流阻力，使狹窄側的PTT有延長的現象。實驗一結果顯示，該系統在訊雜比（SNR）大於25dB的情況下，能夠篩選出有效的PTT，並且誤差小於15ms。在實驗二中，雙側PTT的差值會隨著壓脈帶壓力的上升而有顯著的上升，驗證該系統能檢測出血管阻力改變所引起的PTT變化。臨床試驗結果顯示，7名狹窄症狀的HD患者（DOS = 42 ± 7.2%）與6名健康受試者相比，雙手PTT差值具有顯著差異（p < 0.001）。此外，雙側PTT差值也與狹窄程度呈高度相關（r = 0.92）。上述實驗結果表明，該系統和演算法能有效評估狹窄造成的雙手PTT差值變化，具備在居家進行自我檢測的潛力。最後，本研究將上述系統整合於智慧手錶app中，欲探討智慧手錶用於居家AVF照護的可行性。然而目前使用之智慧手錶受到硬體限制，無法有效評估DOS，但臨床問卷結果仍顯示智慧手錶在AVF照護中具有很大的應用潛力。

Patients with end-stage kidney disease (ESRD) primarily rely on arteriovenous fistulas (AVF) for hemodialysis (HD) to replace kidney function. However, AVFs often develop symptoms of stenosis. Without continuous monitoring of AVF patency, there is a risk of stenosis worsening into complications such as thrombosis or aneurysm, ultimately leading to AVF dysfunction and significantly impacting dialysis efficacy. Clinical practices typically use ultrasound or angiography to assess the degree of stenosis (DOS) at AVFs, which is limited to hospital or clinic settings. According to the literature, there is currently a lack of suitable home monitoring devices for HD patients to self-assess AVF stenosis. In light of this, this study proposed an AVF homecare system enabling HD patients to self-measure AVF patency, thereby preventing AVF dysfunction. This system could synchronously measure electrocardiogram (ECG) and bilateral photoplethysmography (PPG) signals, transmitting data to a mobile app via Bluetooth. The app integrated real-time signal display, feature extraction, and elimination of distorted pulse transit time (PTT) algorithms for DOS assessment. This study analyzed DOS by calculating the bilateral PTT difference using ECG and bilateral PPG signals. Previous research has shown a strong correlation between asymmetry in bilateral PTT and DOS, indicating prolonged PTT on the stenotic side due to increased vascular resistance. The results of the first experiment showed that the system could detect PTT with an error of less than 15ms when the signal-to-noise ratio (SNR) was greater than 25dB. The second experiment validated the system's capability to detect PTT changes caused by variations in vascular resistance, as evidenced by an increase in bilateral PTT difference with increasing cuff pressure. The clinical trial results showed that the PTT difference between both hands in 7 HD patients with stenosis (DOS = 42 ± 7.2%) was significantly different compared to 6 healthy subjects (p < 0.001). Additionally, the bilateral PTT difference showed a strong correlation with DOS (r = 0.92). These results demonstrated the effectiveness of the system and algorithms in assessing changes in bilateral PTT due to stenosis, underscoring their potential for home stenosis detection. Furthermore, to enhance the convenience of home AVF care, this study integrated the aforementioned system into a smartwatch app to explore the feasibility of using smartwatches for home AVF care. However, the current smartwatches have hardware limitations that prevent effective evaluation of DOS. Despite this, clinical survey results still showed that smartwatches have great potential for use in AVF care.

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