文獻(xiàn)翻譯-移動(dòng)通信在多功能遠(yuǎn)程醫(yī)療保健系統(tǒng)中的應(yīng)用

移動(dòng)通信在多功能遠(yuǎn)程醫(yī)療保健系統(tǒng)中的應(yīng)用摘要：本論文主要研究方向是對(duì)遠(yuǎn)程醫(yī)療和家庭監(jiān)測(cè)提供有效的緊急措施?？赡艹霈F(xiàn)緊急病例的場(chǎng)所很多，常見的有救護(hù)車，鄉(xiāng)村衛(wèi)生所及其它偏遠(yuǎn)醫(yī)療場(chǎng)所，比如船在廣闊的海面航行時(shí)也是一個(gè)很普通的可能的緊急醫(yī)療場(chǎng)所的例子，不過我們監(jiān)測(cè)的重點(diǎn)是醫(yī)療遙感監(jiān)測(cè)和家庭遠(yuǎn)程醫(yī)療。為了滿足上述不同領(lǐng)域的發(fā)展需求，我們?cè)O(shè)計(jì)了一個(gè)兼具實(shí)時(shí)、儲(chǔ)存和轉(zhuǎn)送功能的設(shè)備，該設(shè)備由一個(gè)基本單元和一個(gè)遠(yuǎn)程醫(yī)療單元組成。一個(gè)完整的系統(tǒng)可以用于在救護(hù)車、鄉(xiāng)村衛(wèi)生所和輪船上處理緊急醫(yī)療事故，只需在緊急情況處安裝一個(gè)可移動(dòng)的遠(yuǎn)程醫(yī)療單元，而在醫(yī)院專家處安裝一個(gè)基本單元；還可加強(qiáng)重病特別護(hù)理的防范工作，給重點(diǎn)護(hù)理組的醫(yī)生安裝一個(gè)基本可移動(dòng)單元，同時(shí)遠(yuǎn)程醫(yī)療單元仍在重點(diǎn)護(hù)理病人所在地，這樣就可實(shí)現(xiàn)對(duì)家庭的無線監(jiān)測(cè)，通過安裝遠(yuǎn)程醫(yī)療單元在病人的家里，而基本單元在醫(yī)院或者是醫(yī)生的辦公室。該系統(tǒng)可傳輸重要的生物信號(hào)包括病人的肖像。而傳輸工作可通過GSM移動(dòng)網(wǎng)絡(luò)系統(tǒng)、衛(wèi)星連接系統(tǒng)或那些較清晰的舊式電話系統(tǒng)進(jìn)行。用這個(gè)裝置，在處理突發(fā)事故或遠(yuǎn)程醫(yī)療事故時(shí)，一個(gè)專業(yè)醫(yī)生通過信息處理可以“移動(dòng)”到病人所在地，從而指導(dǎo)非專業(yè)人員。為了保護(hù)和存儲(chǔ)在遠(yuǎn)程醫(yī)療過程中相互交換的所有數(shù)據(jù)，我們又開發(fā)了一個(gè)咨詢單元，使用多媒體資料庫(kù)存儲(chǔ)和管理系統(tǒng)收集的數(shù)據(jù)。該系統(tǒng)技術(shù)上已被多個(gè)無線電通訊方法所檢測(cè)，另外它已在三個(gè)不同國(guó)家臨床試驗(yàn)，使用的是標(biāo)準(zhǔn)醫(yī)學(xué)協(xié)議。背景遠(yuǎn)程醫(yī)療就是衛(wèi)生保健的傳遞及一段距離內(nèi)使用無線電通信手段實(shí)現(xiàn)醫(yī)學(xué)知識(shí)的共享。所以，遠(yuǎn)程醫(yī)療的目的是為了給人手不足的偏遠(yuǎn)地區(qū)提供專家級(jí)的衛(wèi)生保健，通過現(xiàn)代化通信和信息知識(shí)提供先進(jìn)的緊急醫(yī)療措施。遠(yuǎn)程醫(yī)療的概念是大約30年前隨著一些現(xiàn)在很普通的技術(shù)，比如電話、傳真機(jī)等提出的。目前，遠(yuǎn)程醫(yī)療系統(tǒng)包括的工藝技術(shù)有交互式視頻、高清晰度監(jiān)視器、高速互聯(lián)網(wǎng)和交換系統(tǒng)及高速無線電通信含纖維光學(xué)和衛(wèi)星。實(shí)時(shí)又專業(yè)化的醫(yī)學(xué)治療可以很大地提高人手不足的鄉(xiāng)村、偏遠(yuǎn)地區(qū)的衛(wèi)生保健服務(wù)。有效的突發(fā)病例遠(yuǎn)程醫(yī)療措施和家庭監(jiān)測(cè)方案是我們這個(gè)課題主要討論的范圍。在很多各種各樣的研究里，這個(gè)課題都是至關(guān)重要的。盡管救護(hù)車、鄉(xiāng)村衛(wèi)生所還有航海的輪船都可能發(fā)生緊急病例，但我們監(jiān)測(cè)的重點(diǎn)是醫(yī)療遙感勘測(cè)和后來的遠(yuǎn)程家庭醫(yī)療。在緊急病例中必須進(jìn)行立即治療，最近的調(diào)查表明入院前早期而又專業(yè)化的病人護(hù)理有利于病人的存活，尤其是嚴(yán)重的頭部損傷、脊髓和內(nèi)臟損傷，為了病人以后的康復(fù)，處理病人的手段至關(guān)重要。我們可以看看過去的車輛事故統(tǒng)計(jì)：在1997年，美國(guó)報(bào)道的6753500事故中有42000人喪身，2182660個(gè)司機(jī)，1125890個(gè)乘客受傷；歐洲同樣時(shí)期有50000個(gè)人因撞車而喪身，而50萬人嚴(yán)重受傷；另外1997年，在希臘一個(gè)國(guó)家有高達(dá)1/3的人是因撞車而死，2500個(gè)致命傷害中77.4%受傷時(shí)遠(yuǎn)離有能力的衛(wèi)生保健機(jī)構(gòu)，所以耗費(fèi)了很長(zhǎng)一段時(shí)間。此外，同樣的調(diào)查表明66%的死者是在死前最近的24小時(shí)喪身的。減小這種事故的死亡率是完全可能的，可通過采用一些病人可更好地進(jìn)行院前護(hù)理、監(jiān)測(cè)的方法和策略。療養(yǎng)監(jiān)測(cè)也可解決病人突發(fā)情況，重點(diǎn)就在于醫(yī)院對(duì)重點(diǎn)護(hù)理組的病人進(jìn)行持續(xù)的監(jiān)控，同時(shí)把監(jiān)控信息隨時(shí)隨地傳給能夠勝任的醫(yī)生。這樣，負(fù)責(zé)的醫(yī)生就的24小時(shí)掌握病人情況，即使不在場(chǎng)時(shí)也可通過先進(jìn)的無線電通信手段提供重要的咨詢，換句話說，視頻監(jiān)控是完全可行的。方法遠(yuǎn)程醫(yī)療系統(tǒng)的發(fā)展趨勢(shì)由上所述，本論文的研究范圍是設(shè)計(jì)并實(shí)現(xiàn)一個(gè)綜合的醫(yī)療系統(tǒng)，該系統(tǒng)可以處理不同距離醫(yī)療系統(tǒng)的需要，尤其表現(xiàn)在以下幾方面：?給救護(hù)車，鄉(xiāng)村衛(wèi)生所（或其他偏遠(yuǎn)的衛(wèi)生機(jī)構(gòu)）和航海的輪船提供緊急醫(yī)療措施?實(shí)現(xiàn)對(duì)重點(diǎn)護(hù)理病人的監(jiān)測(cè)提供家庭護(hù)理，尤其是那些遭受慢性或永久性疾病的人（像心臟?。?，換句話說，我們研究的多功能系統(tǒng)由兩個(gè)主要部分組成：a.遠(yuǎn)程醫(yī)療單元（它可以是手提式電腦或其它）基本單元或醫(yī)生單元（它也可是手提式電腦或其它，一般都位于中心醫(yī)院里面基本單元或醫(yī)生單元（它也可是手提式電腦或其它，一般都位于中心醫(yī)院里面圖一描述了系統(tǒng)的總體體系機(jī)構(gòu)，系統(tǒng)的每個(gè)不同的應(yīng)用即遠(yuǎn)程醫(yī)療單元位于病人所在處，而基本單元（或是叫醫(yī)生單元）即接收和監(jiān)測(cè)病人的生理信號(hào)及肖像處。遠(yuǎn)程醫(yī)療裝置負(fù)責(zé)收集病人的資料（生理信號(hào)和肖像），然后自動(dòng)把檢測(cè)到的信號(hào)傳送到基本單元?；締卧梢唤M用戶指令軟件組成，運(yùn)用這套指令可以接收遠(yuǎn)程醫(yī)療裝置的資料、反饋信息及把重要信息存儲(chǔ)在地方資料室。該系統(tǒng)應(yīng)用很廣泛（每次只須稍作改變），可滿足現(xiàn)代衛(wèi)生保健的發(fā)展需求。在系統(tǒng)技術(shù)實(shí)現(xiàn)以前，上述遠(yuǎn)程醫(yī)療系統(tǒng)應(yīng)用的總設(shè)想應(yīng)根據(jù)目前的發(fā)展趨勢(shì)和需求而制定，只有這樣，在設(shè)計(jì)和發(fā)展過程中，才能把諸多因素都考慮進(jìn)去，所以才能在任何環(huán)境和情形下達(dá)到最大的適用性和可用性。表一提供了這個(gè)總思路的結(jié)構(gòu)，，同時(shí)兼顧了一系列可影響遠(yuǎn)程醫(yī)療的標(biāo)準(zhǔn)（如價(jià)格、輕便性、自治性、裝置的重量和大小、計(jì)算機(jī)、攝像機(jī)的類型和質(zhì)量、所采用的通訊方法），除此之外遠(yuǎn)程醫(yī)療的應(yīng)用還可通過其它標(biāo)準(zhǔn)檢驗(yàn)，像安全需要，傳輸類型（連續(xù)地存儲(chǔ)和轉(zhuǎn)送），心電圖要求等。這些在系統(tǒng)總體技術(shù)描述中將作詳細(xì)說明。系統(tǒng)設(shè)計(jì)和技術(shù)實(shí)現(xiàn)由上述可知，系統(tǒng)由兩個(gè)獨(dú)立模塊組成（圖一）：a）一個(gè)位于病人所在地，叫做遠(yuǎn)程醫(yī)療單元。b）另一個(gè)位于醫(yī)生所在地，叫做基本單元。醫(yī)生在緊急病例或檢測(cè)一個(gè)偏遠(yuǎn)地方病人時(shí)可使用該系統(tǒng)。系統(tǒng)的設(shè)計(jì)和實(shí)現(xiàn)都建立在對(duì)用戶要求的詳細(xì)分析和對(duì)系統(tǒng)功能的具體反應(yīng)的基礎(chǔ)上。而研究主要以遠(yuǎn)程醫(yī)療項(xiàng)目所經(jīng)歷的過程為基礎(chǔ)，像救護(hù)車和急救112，它們使用遠(yuǎn)程醫(yī)療功能性裝置的功能原型已經(jīng)建立了，且通過了初步評(píng)估。通過這些具體實(shí)踐，我們已經(jīng)定相了解了實(shí)現(xiàn)遠(yuǎn)程醫(yī)療裝置的需要，這將進(jìn)一步促進(jìn)我們形成一個(gè)靈活的體系結(jié)構(gòu)，可用于需要信息傳輸?shù)木o急病例或者是監(jiān)測(cè)病例。遠(yuǎn)程醫(yī)療單元負(fù)責(zé)從易發(fā)地帶收集和傳輸生理信號(hào)和病人的肖像，而醫(yī)生單元負(fù)責(zé)接收和顯示輸入數(shù)據(jù)。兩個(gè)場(chǎng)所間的信息流（分層描述）如圖二所示。a）遠(yuǎn)程醫(yī)療單元遠(yuǎn)程醫(yī)療單元主要包括四個(gè)模塊，生理信號(hào)獲得模塊，負(fù)責(zé)接收生理信號(hào)；數(shù)碼相機(jī)模塊負(fù)責(zé)捕獲圖像；處理部件大多是私人計(jì)算機(jī)；通訊模塊（GSM、衛(wèi)星或光學(xué)地面模擬器）。所收集的病人生理信號(hào)（然后傳送到基本單元）主要有：心電圖，由病人所用的監(jiān)視器決定?心跳率無入侵血壓?入侵血壓?體溫?肺活量所使用的計(jì)算機(jī)由遠(yuǎn)程應(yīng)用的類型決定（遠(yuǎn)程醫(yī)療單元所發(fā)揮的作用），如表一所示，a）要求系統(tǒng)自動(dòng)化，形狀小的，一臺(tái)像東芝，lOOct的筆記本電腦即可，較輕便的機(jī)器裝置如圖3所示°b）要求半自動(dòng)，大小不限的，采用典型的奔騰處理機(jī)即可。c）而那些不要求自動(dòng)化，輕便及大小的，一般的臺(tái)式機(jī)即可選用。遠(yuǎn)程醫(yī)療單元的控制是完全自動(dòng)化的。遠(yuǎn)程醫(yī)療單元用戶要做的僅僅是把生理信號(hào)檢測(cè)器連接到病人，然后打開計(jì)算機(jī)。計(jì)算機(jī)將自動(dòng)連接到基本單元。盡管基本單元幾乎控制了系統(tǒng)的所有操作，遠(yuǎn)程醫(yī)療單元用戶仍需掌握一部分操作指令，這樣當(dāng)系統(tǒng)處于偏遠(yuǎn)衛(wèi)生所或輪船上時(shí)，兩個(gè)地方的人就可對(duì)話了。b）基本單元（或醫(yī)生單元）基本單元主要由一臺(tái)接有調(diào)制解調(diào)器的精密計(jì)算機(jī)組成，它的作用主要是負(fù)責(zé)數(shù)據(jù)交換。另外，基本單元的計(jì)算機(jī)還負(fù)責(zé)顯示遠(yuǎn)程醫(yī)療單元的輸入信號(hào)。當(dāng)一個(gè)專家使用醫(yī)院以外的基本單元時(shí)，比如在重病特別護(hù)理病房，由圖一用一臺(tái)GSM的筆記本電腦或一臺(tái)裝有POTS調(diào)制解調(diào)的臺(tái)式機(jī)就可。而當(dāng)基本單元位于醫(yī)院里時(shí)，只需一臺(tái)連接到醫(yī)院信息網(wǎng)絡(luò)并裝有POTS調(diào)制解調(diào)的臺(tái)式機(jī)。專家們就可把它作為一個(gè)處理終端。通過基本單元，用戶可以完全控制遠(yuǎn)程醫(yī)療端。用戶還能夠監(jiān)測(cè)與客戶端（遠(yuǎn)程醫(yī)療單元）的連接狀態(tài)，發(fā)送像圖四那樣的操作模式（生理信號(hào)和圖像）到遠(yuǎn)程醫(yī)療單元。只要基本單元連接到醫(yī)院局域網(wǎng)，用戶可選擇連接到任何一個(gè)遠(yuǎn)程醫(yī)療單元，如圖五所示基本單元的入網(wǎng)用戶可以選擇連接到任何一個(gè)遠(yuǎn)程醫(yī)療單元，入網(wǎng)單元可以是重點(diǎn)護(hù)理組的遠(yuǎn)程醫(yī)療單元或通過電話線上網(wǎng)的遠(yuǎn)距離移動(dòng)用戶單元?；締卧脩艨梢员O(jiān)測(cè)來自遠(yuǎn)程醫(yī)療端的生理或圖像信號(hào)，而且也能夠一直與病人進(jìn)行交談。該單元可完全控制遠(yuǎn)程醫(yī)療部分。醫(yī)生可以發(fā)送所有可能的命令來獲取圖像和生理信號(hào)，圖6顯示了一個(gè)典型的生理信號(hào)接收窗口（持續(xù)操作）。當(dāng)系統(tǒng)操作圖像模塊時(shí)，醫(yī)生可以在圖像上加些注解，然后把加注解后的圖像發(fā)送到遠(yuǎn)程醫(yī)療端，遠(yuǎn)程醫(yī)療端的用戶也可以把接收到的信息再加上注解，然后反饋回基本單元處。當(dāng)系統(tǒng)操作生理信號(hào)模塊時(shí)（如圖6所示），對(duì)重要生理信號(hào)的傳輸方法有兩種，連續(xù)傳輸、儲(chǔ)存和轉(zhuǎn)送傳輸?shù)姆椒?。采用什么方法取決于所傳輸?shù)男碾妶D的波形通道和無線通路的數(shù)據(jù)傳輸率。持續(xù)操作時(shí)，基本端用戶可以向遠(yuǎn)程醫(yī)療監(jiān)測(cè)端發(fā)送指令對(duì)波形進(jìn)行測(cè)量，如血壓；用戶也可暫停輸入心電圖。c）技術(shù)約束—可行性生理信號(hào)傳輸不僅是生理信號(hào)，監(jiān)測(cè)的信息像警鈴或監(jiān)測(cè)到的狀況也需從遠(yuǎn)程醫(yī)療端傳輸?shù)交径?，ECG波形和SPO2或CO2波形（若可獲得）是連續(xù)的傳輸信號(hào)。對(duì)所有的監(jiān)測(cè)器，ECG數(shù)據(jù)以10bits/樣品或12bits/樣品進(jìn)行采樣，采樣率是200樣品/s，所以對(duì)一個(gè)ECG通道相當(dāng)于是2000bits/s或2400bits/s.SPO2或CO2波形是以10bits/樣品取樣，取樣率是100樣品/s,所以一個(gè)通道就是lOOObits/s。最新監(jiān)測(cè)數(shù)據(jù)是以1次/s進(jìn)行刷新，所以傳輸少量數(shù)據(jù)大約可以達(dá)到200bits/s,系統(tǒng)使用的所有監(jiān)測(cè)器可以提供收集到的信號(hào)的數(shù)字輸出量。圖像傳輸遠(yuǎn)程醫(yī)療端數(shù)碼相機(jī)所能捕獲的圖像是320*240像素，采用的是JPEG進(jìn)行壓縮,最終數(shù)據(jù)大約是5-6kB,取決于使用JPEG的壓縮率。傳輸率信號(hào)是通過GSM、衛(wèi)星或POTS傳輸?shù)?。系統(tǒng)技術(shù)測(cè)試使用的GSM網(wǎng)絡(luò)，目前允許的數(shù)據(jù)傳輸率達(dá)到了9600bps（但處于正常的操作狀態(tài)下），使用高速環(huán)繞交換數(shù)據(jù)時(shí)可達(dá)到43200bps.衛(wèi)星連接傳輸率取決于儀器和衛(wèi)星系統(tǒng)的使用場(chǎng)合；大概范圍是2400bps到64000bps。使用不同種類的衛(wèi)星系統(tǒng)會(huì)增加儀器的價(jià)錢和用戶的開銷。像我們這種情況使用INMARAS電話系統(tǒng)即可，而數(shù)據(jù)傳輸率僅僅是2400bps，但儀器便宜，開銷少。POTS可以達(dá)到的數(shù)據(jù)傳輸率是56000bps，所以它能夠支持連續(xù)而又快速的信息傳輸（如表二所示）。通過無線通訊傳輸實(shí)際所能達(dá)到的數(shù)據(jù)傳輸率從來不會(huì)超過理論值，而實(shí)際數(shù)據(jù)傳輸率取決于系統(tǒng)使用的地區(qū)和時(shí)間。傳輸生理信號(hào)有兩種方法實(shí)時(shí)傳輸，連續(xù)地將信號(hào)從客戶端傳輸?shù)郊曳?wù)器；儲(chǔ)存和轉(zhuǎn)發(fā)傳輸，信號(hào)提前獲得并儲(chǔ)存在客戶端，然后作為文件傳輸給服務(wù)器。采取什么方法主要取決于所使用的無線電通訊的最大數(shù)據(jù)傳輸率和不同情況下生理信號(hào)監(jiān)測(cè)器的數(shù)字輸出量。最后的結(jié)果是"多功能"電子醫(yī)療系統(tǒng),是一個(gè)能在不同的應(yīng)用領(lǐng)域中被采用的靈活的體系結(jié)構(gòu)，該系統(tǒng)已通過了很多醫(yī)療設(shè)備和無線通信設(shè)備的試驗(yàn)。本論文所針對(duì)的對(duì)象是鄉(xiāng)村衛(wèi)生所、救護(hù)車或航海的輪船。數(shù)據(jù)傳輸使用的是TCP/IP網(wǎng)絡(luò)協(xié)議，網(wǎng)絡(luò)傳輸數(shù)據(jù)使用TCP/IP協(xié)議簡(jiǎn)單且容易，又具有高帶寬、低誤碼率。要傳輸n字節(jié)的數(shù)據(jù)塊，使用TCP/IP協(xié)議，需在報(bào)頭另加55字節(jié)。在傳輸少量數(shù)據(jù)的情況下，這加額外增加大量數(shù)據(jù)（例如，當(dāng)傳輸10字節(jié)時(shí)，網(wǎng)絡(luò)將自動(dòng)增加至65字節(jié)）。當(dāng)傳輸?shù)臄?shù)據(jù)流大小大于最大允許的傳輸單元時(shí)，這個(gè)數(shù)據(jù)流將分裂成幾個(gè)較小的數(shù)據(jù)包，每個(gè)包都和允許的最大傳輸單元一樣大，而達(dá)到目的地時(shí)，所有分裂的包將會(huì)重新連接；如果其中分裂的任何一個(gè)包丟失，將會(huì)引起嚴(yán)重錯(cuò)誤?？紤]到數(shù)據(jù)傳輸?shù)纳鲜鰞煞N情況，尤其是那種低帶寬、高差錯(cuò)率的網(wǎng)絡(luò)（像GSM移動(dòng)網(wǎng)絡(luò)和衛(wèi)星連接）。采用一種充分利用帶寬的方法，使傳輸?shù)臄?shù)據(jù)要么充分大，要么充分小。為了測(cè)量使用GSM網(wǎng)絡(luò)時(shí)TCP/IP的執(zhí)行，對(duì)不同大小的數(shù)據(jù)塊進(jìn)行測(cè)試，該測(cè)試使用的是GSM調(diào)制解調(diào)器，NOKIA2.0電話卡。進(jìn)行試驗(yàn)時(shí)，選擇了從71到479字節(jié)的數(shù)據(jù)包，數(shù)據(jù)包的大小與發(fā)送的數(shù)據(jù)率成正比，發(fā)送時(shí)使用串口RS232。數(shù)據(jù)包的大小依次有39.287.335.383.431.455.479字節(jié)。由上所述，圖8是對(duì)數(shù)據(jù)傳輸?shù)臏y(cè)量。我們對(duì)要選擇的數(shù)據(jù)塊大小的要求是：不給傳輸數(shù)據(jù)加過長(zhǎng)的報(bào)頭，不會(huì)引起數(shù)據(jù)傳輸?shù)姆謮K，不會(huì)給信號(hào)的傳輸引起很大的時(shí)延。經(jīng)多方面考慮，我們選擇的數(shù)據(jù)塊大小是431字節(jié)。結(jié)論我們已經(jīng)開發(fā)了適于遠(yuǎn)程醫(yī)療應(yīng)用的醫(yī)療產(chǎn)品，該裝置使用GSM移動(dòng)電話連接，衛(wèi)星連接或POTS連接，允許收集和傳輸生理信號(hào)、病人的肖像，具有雙向視頻功能。在接收數(shù)據(jù)和與專家交談時(shí)，允許用戶在可自由模式下操作，這種先進(jìn)的人為控制界面提高了系統(tǒng)的功能性。為了在日常健康預(yù)防中介紹該系統(tǒng)，通過使用一個(gè)可控制的醫(yī)療協(xié)議系統(tǒng)已被臨床試驗(yàn)。目前，該系統(tǒng)已經(jīng)在兩個(gè)不同國(guó)家，希臘和塞浦路斯安裝且正在使用。據(jù)現(xiàn)在的發(fā)展情形可以看出系統(tǒng)很有前景，所以為滿足未來需求，激勵(lì)著我們不斷發(fā)展和提高該系統(tǒng)。Multi-purposeHealthCareTelemedicineSystemswithmobilecommunicationlinksupportEKyriacou*1,2,SPavlopoulos1,ABerler1,MNeophytou1,ABourka1,AGeorgoulas1,AAnagnostaki1,DKarayiannis3,CSchizas2,CPattichis2,AAndreou2andDKoutsouris1abstractTheprovisionofeffectiveemergencytelemedicineandhomemonitoringsolutionsarethemajorfieldsofinterestdiscussedinthisstudy.Ambulances,RuralHealthCenters(RHC)orotherremotehealthlocationsuchasShipsnavigatinginwideseasarecommonexamplesofpossibleemergencysites,whilecriticalcaretelemetryandtelemedicinehomefollow-upsareimportantissuesoftelemonitoring.Inordertosupporttheabovedifferentgrowingapplicationfieldswecreatedacombinedreal-timeandstoreandforwardfacilitythatconsistsofabaseunitandatelemedicine(mobile)unit.Thisintegratedsystem:canbeusedwhenhandlingemergencycasesinambulances,RHCorshipsbyusingamobiletelemedicineunitattheemergencysiteandabaseunitatthehospital-expert'ssite,enhancesintensivehealthcareprovisionbygivingamobilebaseunittotheICUdoctorwhilethetelemedicineunitremainsattheICUpatientsiteandenableshometelemonitoring,byinstallingthetelemedicineunitatthepatient'shomewhilethebaseunitremainsatthephysician'sofficeorhospital.Thesystemallowsthetransmissionofvitalbiosignals(3-2leadECG,SPO2,NIBP,IBP,Temp)andstillimagesofthepatient.ThetransmissionisperformedthroughGSMmobiletelecommunicationnetwork,throughsatellitelinks(whereGSMisnotavailable)orthroughPlainOldTelephonySystems(POTS)whereavailable.Usingthisdeviceaspecialistdoctorcantelematically"move"tothepatient'ssiteandinstructunspecializedpersonnelwhenhandlinganemergencyortelemonitoringcase.Duetotheneedofstoringandarchivingofalldatainterchangedduringthetelemedicinesessions,wehaveequippedtheconsultationsitewithamultimediadatabaseabletostoreandmanagethedatacollectedbythesystem.Theperformanceofthesystemhasbeentechnicallytestedoverseveraltelecommunicationmeans;inadditionthesystemhasbeenclinicallyvalidatedinthreedifferentcountriesusingastandardizedmedicalprotocol.BackgroundTelemedicineisdefinedasthedeliveryofhealthcareandsharingofmedicalknowledgeoveradistanceusingtelecommunicationmeans.Thus,theaimofTelemedicineistoprovideexpert-basedhealthcaretounderstaffedremotesitesandtoprovideadvancedemergencycarethroughmoderntelecommunicationandinformationtechnologies.TheconceptofTelemedicinewasintroducedabout30yearsagothroughtheuseofnowadays-commontechnologiesliketelephoneandfacsimilemachines.Today,TelemedicinesystemsaresupportedbyStateoftheArtTechnologieslikeInteractivevideo,highresolutionmonitors,highspeedcomputernetworksandswitchingsystems,andtelecommunicationssuperhighwaysincludingfiberoptics,satellitesandcellulartelephony[1].Theavailabilityofpromptandexpertmedicalcarecanmeaningfullyimprovehealthcareservicesatunderstaffedruralorremoteareas.TheprovisionofeffectiveemergencyTelemedicineandhomemonitoringsolutionsarethemajorfieldsofinterestdiscussedinthisstudy.Thereareawidevarietyofexampleswherethosefieldsarecrucial.Nevertheless,Ambulances,RuralHealthCenters(RHC)andShipsnavigatinginwideseasarecommonexamplesofpossibleemergencysites,whilecriticalcaretelemetryandTelemedicinehomefollow-upsareimportantissuesoftelemonitoring.Inemergencycaseswhereimmediatemedicaltreatmentistheissue,recentstudiesconcludethatearlyandspecializedpre-hospitalpatientmanagementcontributestothepatient'ssurvival[2].Especiallyincasesofseriousheadinjuries,spinalcordorinternalorganstrauma,thewaytheincidentsaretreatedandtransportediscrucialforthefuturewellbeingofthepatients.Aquicklooktopastcaraccidentstatisticspointsoutclearlytheissue:During1997,6753500incidentswerereportedintheUnitedStates[3]fromwhichabout42000peoplelosttheirlives,2182660driversand1125890passengerswereinjured.InEuropeduringthesameperiod50000peoplediedresultingofcarcrashinjuriesandabouthalfamillionwereseverelyinjured.Furthermore,studiescompletedin1997inGreece[4],acountrywiththeworld'sthirdhighestdeathrateduetocarcrashes,showthat77,4%ofthe2500fatalinjuriesinaccidentswereinjuredfarawayfromanycompetenthealthcareinstitution,thusresultinginlongresponsetimes.Inaddition,thesamestudiesreportedthat66%ofdeceasedpeoplepassedawayduringthefirst24hours.Thereductionofallthosehighdeathratesisdefinitelyachievablethroughstrategiesandmeasures,whichimproveaccesstocare,administrationofpre-hospitalcareandpatientmonitoringtechniques.Criticalcaretelemetryisanothercaseofhandlingemergencysituations.Themainpointistomonitorcontinuouslyintensivecareunits'(ICU)patientsatahospitalandatthesametimetodisplayalltelemetryinformationtothecompetentdoctorsanywhere,anytime[14].Inthispattern,theresponsibledoctorcanbeinformedaboutthepatient'sconditionata24-hourbasisandprovidevitalconsultingevenifhe'snotphysicallypresent.ThisisfeasiblethroughadvancedtelecommunicationsmeansorinotherwordsviaTelemedicine.MethodsTrendsandneedsofTelemedicinesystemsAsmentionedabove,scopeofthisstudywastodesignandimplementanintegratedTelemedicinesystem,abletohandledifferentTelemedicineneedsespeciallyinthefieldsof:?Emergencyhealthcareprovisioninambulances,RuralHospitalCenters(oranyotherremotelocatedhealthcenter)andnavigatingShips?Intensivecarepatientsmonitoring?Hometelecare,especiallyforpatientssufferingfromchronicand/orpermanentdiseases(likeheartdisease).Inotherwordswedetermineda"Multi-purpose"systemconsistingoftwomajorparts:a)Telemedicineunit(whichcanbeportableornotportabledependingonthecase)andb)Baseunitordoctor'sunit(whichcanbeportableornotportabledependingonthecaseandusuallylocatedataCentralHospital).sFigureIOverallsysiemarchit&cture齊sFigureIOverallsysiemarchit&cture齊1?1頤冊(cè)加盼Cn，?Figure1describestheoverallsystemarchitecture.IneachdifferentapplicationtheTelemedicineunitislocatedatthepatient'ssite,whereasthebaseunit(ordoctor'sunit)islocatedattheplacewherethesignalsandimagesofthepatientaresentandmonitored.TheTelemedicinedeviceisresponsibletocollectdata(biosignalsandimages)fromthepatientandautomaticallytransmitthemtothebaseunit.Thebaseunitiscomprisedofasetofuser-friendlysoftwaremodules,whichcanreceivedatafromtheTelemedicinedevice,transmitinformationbacktoitandstoreimportantdatainalocaldatabase.Thesystemhasseveraldifferentapplications(withsmallchangeseachtime),accordingtothecurrenthealthcareprovisionnatureandneeds.Beforethesystem'stechnicalimplementation,anoverviewofthecurrenttrendsandneedsintheaforementionedTelemedicineapplicationswasmade,sothatthedifferentrequirementsaretakenintoaccountduringdesignanddevelopment,thusensuringmaximumapplicabilityandusabilityofthefinalsystemindistinctenvironmentsandsituations.Table1providestheresultsofthisoverview,whichwasdonetowardsapredefinedlistofcriteriathatusuallyinfluenceaTelemedicineapplicationimplementation(cost,portability,autonomy,weightandsizeofTelemedicinedevice,typeandqualityofPCandcamera,communicationmeansused).Besidestheabove,theTelemedicineapplicationscanbeexaminedtowardsothercriteria,likeforexamplesecurityneeds,transmissiontype(continuos,store&forward)needs,ECGleadsrequired(3or12leads),etc.Theselastareexaminedinmoredetailinthenextparagraph,wheretheoveralltechnicaldescriptionofthesystemisprovided.SystemdesignandtechnicalimplementationAsmentionedabove,thesystemconsistsoftwoseparatemodules(Figure1):a)theunitlocatedatthepatient'ssitecalled"Telemedicineunit"andb)theunitlocatedatdoctor'ssitecalled"BaseUnit".TheDoctormightbeusingthesystemeitherinanEmergencycaseorwhenmonitoringapatientfromaremoteplace.Figure2InfornucionFlew^iihintheTekmedicinesystem(Telemedicineand血Figure2InfornucionFlew^iihintheTekmedicinesystem(Telemedicineand血eunits)Tel^rritdlclMLIrut目沖⑷IfOriiTO亡i：比tmsiriEEmru^u^iTg-cuficonru-^h4^IThedesignandimplementationofthesystemwasbasedonadetaileduserrequirementsanalysis,aswellasthecorrespondingsystemfunctionalspecifications.ThestudywasmainlybasedontheexperienceofTelemedicineprojectsnamedAMBULANCE[22]andEmergency112[33]wherefunctionalprototypesofadevicewithemergencyTelemedicinefunctionalitieswasbuiltandextensivelyevaluated.Throughtheseprojectwehadphasedtheneedtoimplementatelemedicinedevice,whichwouldfacilitateaflexiblearchitectureandcouldbeusedinseveralemergencyormonitoringcasesthathavesimiralneedsofinformationtransmition.TheTelemedicineunitisresponsibleforcollectingandtransmittingbiosignalsandstillimagesofthepatientsfromtheincidentplacetotheDoctor'slocationwhiletheDoctor'sunitisresponsibleforreceivinganddisplayingincomingdata.Theinformationflow(usingalayereddescription)betweenthetwositescanbeseeninFigure2.TableI:OverviewofcurrenttrendsarirdmeedsinT^kinfirediicineapphicatknnsTelleoiredlci^eBaski^eeds-appIkadoLnsCostPortabiiltyAutoootfinrySmallWeight&sizePCtypeCaoirer-aquality6mmiinli-citlonnireaiiksUserfrbendlinesiAiiij^fbularKeMedium'HighHighHighHighPalmcopMediumHighGSMMedium/HighRHCMedium'HighLowLowLowDesktopLaptopMediumHighPOTS.GSMMedium'HighShipMediumHighLow/MediumLow/MediumLowDesktopLaptopMediumHighGSMrSitediceMediumHighHome<areLowLow/MediumLow/MediumLowDesktopLaptopHigh-POTSHigh"InteosliveemeMedium'HighLowLowLowDesktopHighPOTS,GSMMedium/Highrooma)TelemedicineUnitTheTelemedicineunitmainlyconsistsoffourmodules,thebiosignalacquisitionmodule,whichisresponsibleforbiosignalsacquisition,adigitalcameraresponsibleforimagecapturing,aprocessingunit,whichisbasicallyaPersonalComputer,andacommunicationmodule(GSM,SatelliteorPOTSmodem).ThebiosignalacquisitionmodulewasdesignedtooperatewithsomeofthemostcommonportablebiosignalmonitorsusedinemergencycasesorinIntensivecareUnitssuchasa)CRITIKONDINAMAPPLUSMonitorModel8700/9700familyofmonitors,b)PROTOCOL-WelchAllynPropaq1xxVitalSignsMonitor,c)PROTOCOL-WelchAllynPropaqEncore2xxVitalSignsMonitor.Thebiosignalscollectedbythepatient(andthentransmittedtotheBaseUnit)are:?ECGupto12lead,dependingonthemonitorusedineachcase.?OxygenSaturation(SpO2).?HeartRate(HR).?Non-InvasiveBloodPressure(NIBP).?InvasivebloodPressure(IP).?Temperature(Temp)?Respiration(Resp)ThePCuseddependsonthetypeoftheTelemedicineapplication(roleoftheTelemedicineunit).AsshowninTable1:a)incaseswheretheautonomyandsmallsizeofthesystemareimportant(mainlyinambulances),asubnotebooklikeToshibalibretto100ctportablePCisused,apictureofaportabledeviceisshowninFigure3b)incaseswhereweneedsomeautonomybutsizeisnotconsideredanimportantelementaTypicalPentiumportablePCisused;c)incaseswherewedonotnecessarilyneedautonomy,portabilityandsmallsystemsize,aTypicalPentiumDesktopPCisused.Figure3Pictureoft^l^m^dicinemobileunic(monitorPropaq2xxisuud)ThecontroloftheTelemedicineunitisfullyautomatic.TheonlythingthetelemedicineunituserhastodoisconnectthebiosignalmonitortothepatientandturnonthePC.ThePCthenperformstheconnectiontothebaseunitautomatically.Althoughthebaseunitbasicallycontrolstheoverallsystemoperation,theTelemedicineunitusercanalsoexecuteanumberofcommands.Thisoptionisusefulwhenthesystemisusedinadistancehealthcenterorinashipandaconversationbetweenthetwositestakesplace.b)BaseUnit(orDoctor'sUnit)ThebaseunitmainlyconsistsofadedicatedPCequippedwithamodem,whichisresponsiblefordatainterchange.InadditionthebaseunitpcisresponsiblefordisplayingincomingsignalsfromtheTelemedicineunit.Whenanexpertdoctorusesthebaseunitlocatedoutsidethehospitalarea(likeintheIntensiveCareRoomapplication-seeFigure1,aportablePCequippedwithaGSMmodemoradesktopPCequippedwithaPOTSmodemisused.Whenthebaseunitislocatedinthehospital,adesktopPCconnectedtotheHospitalInformationNetwork(HIS)equippedwithaPOTSmodemcanadditionallybeused;theexpertdoctorusesitasaprocessingterminal.Throughthebaseunit,userhasthefullcontrolofthetelemedicinesession.Theuserisabletomonitortheconnectionwithaclient(telemedicineunit),sendcommandstothetelemedicineunitsuchastheoperationmode(biosignalsorimages)Figure4.IncaseswerethebasestationisconnectedtoaHospitalLANtheusercanchoosetowhichofthetelemedicineunitstoconnectto,asshowninFigure5theuserofthebaseunitisabletochooseandconnecttoanyoneofthetelemedicineunitsconnectedonthenetwork.TheunitsconnectedonthenetworkcanbeICUtelemedicineunitsordistancemobiletelemedicineunitsconnectedthroughphonelines.TheBaseUnit'susercanmonitorbiosignalsorstillimagescomingfromtheTelemedicineunit,thuskeepingacontinuousonlinecommunicationwiththepatientsite.ThisunithasthefullcontroloftheTelemedicinesession.Thedoctor(user)cansendallpossiblecommandsconcerningbothstillimagetransmissionandbiosignalstransmission.Figure6presentsatypicalbiosignal-receivingwindow(continuousoperation).［壁吐亙］I超VkhoFGIcufgft譏i町的乍1更期Biosignakni?dtStiUimagemodeFigure4Contra!Window-BasaUnit]?ifll?KdK：iHeEldtKNurEjdrmectiunTclcmedkincNetwork［壁吐亙］I超VkhoFGIcufgft譏i町的乍1更期Biosignakni?dtStiUimagemodeFigure4Contra!Window-BasaUnit]?ifll?KdK：iHeEldtKNurEjdrmectiunTclcmedkincNetwork5?d?cn4"TpI耳七館H=ri5)匚VtHBtetrnfrlr-ne怎創(chuàng)日ri*門曲前is養(yǎng)slflp.-r*1sto.1iOng-：IPadie-ssk&tFigure5TelemedicineM它軸orkcontral-BaseUnitFigure6BiosignalreceivingwindewitBaseUnicChnniEc)TechnicalConstraints-FeasibilityBiosignalstransmissionAlongwithbiosignals,informationconcerningthemonitor,suchasthealarmsorthemonitorstatus,istransmittedfromtheTelemedicineunittothebaseunit.TheECGwaveformandSpO2orCo2Waveform(whereavailable)isthecontinuoussignalstransmitted,trendsaretransmittedfortherestofdata.ECGdataaresampledatarateof200samples/secby10bits/sampleor12bits/sample,forallmonitorsused,thusresultinginagenerationof2000bits/secand2400bits/secforoneECGchannel.SpO2andCo2waveformsaresampledatarateof100samples/secby10bit/sample;thusresultinginagenerationof1000bits/secforonechannel.TrendsforSpO2,HR,NIBP,BP,Tempandmonitordataareupdatedwitharefreshrateofonepersecond,thusaddingasmallfractionofdatatobetransmittedapproximatelyupto200bits/sec.Allbiosignalsmonitorsusedwiththesystemcanprovidedigitaloutputofthecollectedsignals[36-38].ImagetransmissionImagescapturedbytheTelemedicineunit'scamerahaveresolution320x240pixelandarecompressedusingtheJPEGcompressionalgorithm;theresultingdatasetisapproximately5-KBdependingonthecompressionrateusedfortheJPEGalgorithm[39].TransmissionrateThesignalstransmissionisdoneusingGSM,SatelliteandPOTSlinks.Forthetimebeing,theGSMnetworkthatthesystemwastechnicallytestedon;allowstransmissionofdataupto9600bps(whenoperatingonthenormalmode)andisabletoreachupto43200bpswhenusingtheHSDC(HighSpeedCircuitSwitchedData).Thesatellitelinkstransmissionratedependsontheequipmentandthesatellitesystemusedineachcase;ithasarangefrom2400bpsupto64000bps.Theuseofdifferentsatellitesystemscanincreasethecostofequipmentandcostofuse;inourcasewehadusedanINMARSAT-phoneMini-msystemwhichcantransmitdataonlyupto2400bps,buthaslowequipmentandusecost.PlainOldTelephonySystem(POTS)allowsthetransmissionofdatausingarateupto56000bps,thusenablingthecontinuousandfastinformationtransmission(Table2).Thepracticalmaximumdatatransferrateovertelecommunicationmeansisneverashighasthetheoreticaldatatransferrate.Practicaldataratesdependonthetimeandtheareawherethesystemisused.Biosignalsdatatransmissioncanbedoneintwoways:realtimetransmissionwhereacontinuoussignalistransmittedfromclienttoserverorstoreandforwardtransmissionwheresignalsofapredefinedperiodoftimearestoredintheclientandtransmittedasfilestoserver.Itmainlydependsonthemaximumdatatransferrateofthetelecommunicationlinkusedandthedigitaldataoutputthatthebiosignalmonitorhasineachcase.

Figure7PatientInformacionwindow.HospitaldacabaseUnicResults-DiscussionThefinalresultisa"Multi-purpose"Telemedicinesystem,whichfacilitatesaflexiblearchitecturethatcanbeadoptedinseveraldifferentapplicationfields.Thesystemhasbeentestedandvalidatedforavarietyofmedicaldevicesandtelecommunicationmeans.ResultspresentedinthissectionaretypicalfortheneedsofsystemuseinRuralHealthCenters,inAmbulanceVehiclesorinaNavigatingShip.DatatransmissionisdoneusingtheTCP/IPnetworkprotocol.TransmittingdataoverTCP/IPisatrivialandeasytaskwhenusingnetworks,whichhavehighbandwidthandlowerrorrate.InordertotransmitabufferofnbytesthroughTCP/IPaheaderofabout55bytesisadded,thiswilladdagreatamountofdataespeciallyincasesthatwetransmitsmallbuffers(e.g.whentransmittingabufferof10bytesthenetworkprotocolwillincreasethisbufferto65bytes).WhentransmittingabufferthathassizelargerthantheMaximumTransferUnit(MTU)thisbufferwillbefragmentedintosmallerpacketsthateachonehasthesizeoftheMTU,allsmallpacketswillbereconnectedwhenarrivingatthedestinationsite;thiscasewillcauseproblemswhenoneofthefragmentationpacketsislost[42]Consideringtheabovetwocasesthetransmissionofdata,especiallythroughnetworksthathavelowbandwidthandhigherrorrates(suchasGSMmobilenetworkandSatelliteLinks),hastobedoneinawaythatwillutilizethenetworkuseasmuchaspossible.Thebufferstransmittedmusthavesizethatwantbeeithertoosmallortoobig.InordertomeasuretheperformanceofTCP/IPovertheGSMnetworkseveralsizesofdatabuffershadbeentested.ThetestswereperformedusingGSMmodem,NokiaCardPhone2.0forthetelemedicineunit,andaPOTSmodemUSroboticssportstervoice56KBPSforthebaseunit.ThesetwodevicessupportcompressionprotocolV42bis.Inordertoperformthetests;buffersfrom71upto479byteswereselected;thesizeofbuffersisproportionaltothedataratethatthePropaq2xxsendsthroughtheRS232serialport.Thepacketshadsizes:71,95,143,239,287,335,383,431,455,479bytes.Usingalltheabovebufferswemadesomemeasurementsonthebytesthatwerereceivedandtransmittedtoandfromthebaseunitofthetelemedicinesystem.Figure8showstheresultsofthebytestransmittedandreceivedfromtheserverunitwhenhavingatelemedicineunitconnectedwithGSMtotheserver.Numbers1to10representthesizeofthebuffersused,1forthesmallest(71bytes)upto10forthelargest(479bytes).Themeanvalueofthebytestransmitted/receivedpersecondwasrecordedfor2minutespercase.Ascanbeseentransmittingsmallpacketsofdatacasedthetransmitionofmorebytesbecauseoftheoverheadaddedoneachbuffer.Thecontinuoustransmitionofsmallbuffersalsocasedsomeproblemsonthecommunicationandontheoveralltelemedicineunitoperation;itcouldstoptheoperationoftheprotocoloraddsomeproblemwhenreadingdatafromthemedicalmonitor(toomanysystemresourceswereused).Havinginmindalltheaboveandthemeasurementsofbytestransmitted(Figure8)wehadtoselectabuffersizethat:wouldnotaddtoomuchoverheadtothetransmitteddata,wouldnotcausefragmentationofthetransmittedbuffersandwouldnotaddtoomuchdelayonrealtimetransmittedsignal.Havinginmindalltheabovetheselectedbuffersizeusedwas431bytes.ConclusionsWehavedevelopedamedicaldevicefortelemedicineapplications.ThedeviceusesGSMmobiletelephonylinks,Satellitelinks