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.