經(jīng)皮二氧化碳測定對長時間腹腔鏡手術(shù)患者動脈血二氧化

1、經(jīng)皮二氧化碳測定對長時間腹腔鏡手術(shù)患者動脈血二氧化碳分壓的預(yù)測作用1上海交通大學(xué)醫(yī)學(xué)院附屬瑞金醫(yī)院麻醉科，2上海交通大學(xué)醫(yī)學(xué)院附屬瑞金醫(yī)院上海市微創(chuàng)外科臨床醫(yī)學(xué)中心，200025武曉文1 金玨1 于布為1 鄭民華2【摘要】 目的 通過比擬長時間腹腔鏡手術(shù)直腸及胃切除術(shù)患者的經(jīng)皮二氧化碳TcPCO2、 呼吸末二氧化碳PetCO2、和動脈血二氧化碳PaCO2分壓三個參數(shù)之間的相關(guān)性，從而評價TcPCO2對于此類手術(shù)患者PaCO2的預(yù)測效能。方法 全身麻醉下?lián)衿谛懈骨荤R直腸癌及胃癌根治術(shù)的患者16例，ASA級，以血漿靶濃度為2.0g/ml的異丙酚TCI方式和6地氟醚吸入維持麻醉。建立TcPCO2、P

2、etCO2和PaCO2監(jiān)測，記錄比擬根底、氣腹30min、氣腹60min的TcPCO2、PetCO2 和PaCO2數(shù)值。結(jié)果 16位患者共獲得48個樣本，TcPCO2和PetCO2的數(shù)值變化與PaCO2均顯著相關(guān)，其相關(guān)系數(shù)分別為rTcPCO2PaCO20.84p0.05和rPeTCO2PaCO20.75 (p0.05) 。根底、氣腹30min、氣腹60min三個時間點的TcPCO2與PaCO2仍然相關(guān)，相關(guān)系數(shù)分別為r=0.57、r=0.83和r=0.74p0.05。PetCO2與PaCO2僅在根底狀態(tài)下相關(guān)p0.05)。TcPCO2與PaCO2差值絕對值3mmHg的樣本比例為62，而Pet

3、CO2與PaCO2差值絕對值3mmHg的樣本比例僅為8P0.05。結(jié)論 TcPCO2 與PaCO2具有較高的相關(guān)性與一致性，能夠有效地評價長時程腹腔鏡手術(shù)患者的PaCO2數(shù)值與變化趨勢?！娟P(guān)鍵詞】 經(jīng)皮二氧化碳分壓，呼吸末二氧化碳分壓，動脈血二氧化碳分壓，腹腔鏡手術(shù) 作者單位：1上海交通大學(xué)醫(yī)學(xué)院附屬瑞金醫(yī)院麻醉科，2上海交通大學(xué)醫(yī)學(xué)院附屬瑞金醫(yī)院上海市微創(chuàng)外科臨床醫(yī)學(xué)中心，200025， 上海責任 臨床在評價動脈血二氧化碳分壓Pa CO2變化時，除了使用血氣分析外，主要還是通過呼氣末二氧化碳測定end-tidal carbon dioxide pressure, PetCO2，但是在二氧化碳

4、產(chǎn)量發(fā)生變化，患者通氣模式改變，或者是存在心肺疾患的條件下，后者與PaCO2數(shù)值之間較大的偏差，因而不能準確及時地反映PaCO2變化【1】，所以尋找更加有效的方法成為了臨床研究方向。經(jīng)皮二氧化碳分壓transcutaneous carbon dioxide pressure，TcPCO2測定是一種新穎、簡便、無創(chuàng)性的機體二氧化碳濃度監(jiān)測新方法，能夠準確的反映動脈血二氧化碳分壓，具有準確性好、靈敏度高的優(yōu)點【2】，在臨床麻醉監(jiān)測中被逐漸重視。腹腔鏡手術(shù)是外科學(xué)開展的重大進步，其中新近開展的腹腔鏡下直腸癌根治術(shù)及腹腔鏡下胃癌根治術(shù)更是由于損傷小，恢復(fù)快的優(yōu)點受到醫(yī)生和患者的廣泛接受【3】。但是這類

5、手術(shù)中需要沖入大量的二氧化碳，維持氣腹壓力在1015cmH2O，并且時間較長，患者體內(nèi)的二氧化碳容量和通氣模式都會發(fā)生變化，PetCO2反映PaCO2的效能會降低，此時TcPCO2反映PaCO2的作用如何？這些還是未知，因此本實驗擬通過比擬腹腔鏡直腸癌及胃癌根治術(shù)患者不同時間點的TcPCO2、 PetCO2、和PaCO2 三者之間的相關(guān)性，從而評價TcPCO2對于PaCO2變化的預(yù)測效能。資料與方法病例選擇 本研究方案通過醫(yī)院倫理委員會批準，并經(jīng)患者簽署知情同意書，選擇16例擇期行腹腔鏡輔助的直腸癌根治術(shù)及腹腔鏡輔助的胃癌根治術(shù)的患者，ASA或級，排除患有嚴重的心血管系統(tǒng)及呼吸系統(tǒng)疾的病者。麻

6、醉及監(jiān)測方法 患者入室后開放上肢靜脈，以多功能監(jiān)測儀AS/5，DatexOhmeda，芬蘭監(jiān)測ECG、SpO2、NIBP。用酒精清潔耳垂處皮膚，將TcPCO2監(jiān)測電極SenTec Digital Monitor, SenTec Inc. Switzerland置于患者的一側(cè)耳垂上。麻醉誘導(dǎo)采用異丙酚TCI模式，血漿靶濃度到達4.0g/ml后靜脈推注芬太尼2g/kg和阿曲庫胺0.6mg/kg，隨后經(jīng)口腔明視下氣管內(nèi)插管，機械通氣。術(shù)中以6地氟醚氧流量2L/min持續(xù)吸入以及2.0 g/ml的異丙酚TCI維持麻醉，并根據(jù)術(shù)中需要間斷靜脈推注芬太尼和阿曲庫胺。術(shù)中通過呼吸頻率和潮氣量的調(diào)節(jié)維持Pet

7、CO2在3545mmHg之間。TcPCO2、PetCO2和血氣分析儀i-STAT，美國在監(jiān)測前均進行參數(shù)校正，TcPCO2監(jiān)測15min后才開始氣腹手術(shù)，這段時期為TcPCO2的數(shù)據(jù)平衡期，從而能夠到達穩(wěn)定的數(shù)值。TcPCO2數(shù)值穩(wěn)定后，氣腹前采動脈血測定此時的PaCO2數(shù)值，同時記錄TcPCO2與PetCO2，它們和PaCO2這三個數(shù)值作為根底值。在氣腹建立30min和60min再次采動脈血測定PaCO2，并同時記錄TcPCO2與PetCO2，它們分別是第二和第三采樣點。手術(shù)過程中氣腹壓力維持在15cmH2O水平。統(tǒng)計分析 計量資料以均數(shù)標準差S表示，采用SPSS 13.0統(tǒng)計軟件，通過Pe

8、arson相關(guān)分析評價TcPCO2和PetCO2分別與PaCO2數(shù)據(jù)之間的相關(guān)性。并采用BlandAltman一致性檢驗評價PetCO2和TcPCO2分別與PaCO2之間的一致性。設(shè)定TcPCO2與PaCO2以及PetCO2與PaCO2數(shù)據(jù)差值的絕對值3mmHg為臨床允許的正常偏差范圍，通過卡方檢驗比擬這三個參數(shù)之間正常偏差所占的比例。P0.05為差異有顯著意義。 結(jié)果一般資料 16例患者，男性8例，女性8例；年齡：6511歲44歲86歲，體重：6311 kg4379 kg，其中腹腔鏡下直腸癌根治術(shù)11例，腹腔鏡下胃癌根治術(shù)患者5例。相關(guān)性分析 16例患者的3個采樣點共獲得48個樣本，TcPC

9、O2與PaCO2數(shù)值顯著相關(guān)，r0.84p0.05，其線形回歸方程為：y=0.955x+2.923r20.705, p0.01。PetCO2與PaCO2數(shù)值亦顯著相關(guān)，r0.75 (p0.05)，其線性回歸方程為：y=0.534x+13.055r20.555, p0.01見圖1。在3個不同的采樣點，TcPCO2與PaCO2數(shù)值仍然顯著相關(guān)，其相關(guān)系數(shù)分別為r=0.57、r=0.83和r=0.74p0.05，而PetCO2與PaCO2僅在根底階段顯著相關(guān)，相關(guān)系數(shù)為r=0.55p0.05)。一致性檢驗 PaCO2與TcPCO2數(shù)值間的平均偏差PaCO2TcPCO2為13mmHg，而PaCO2 與

10、PetCO2PaCO2PetCO2的平均偏差為84mmHg見圖2。TcPCO2與PaCO2數(shù)值差距絕對值在3mmHg正常范圍內(nèi)的樣本數(shù)占其總數(shù)的62，而PetCO2與PaCO2數(shù)值差距絕對值在3mmHg正常范圍內(nèi)的樣本數(shù)僅占其總數(shù)的8P0.05。討論本研究通過長時間腹腔鏡手術(shù)患者不同時間的TcPCO2，PetCO2和PaCO2三個參數(shù)之間的比擬發(fā)現(xiàn)：TcPCO2與PaCO2數(shù)值顯著相關(guān)，其兩者之間的一致性優(yōu)于PetCO2與PaCO2，PetCO2僅在氣腹前與PaCO2顯著相關(guān)，隨著氣腹時間的延長，其兩者之間的相關(guān)性消失。腹腔鏡下直腸癌根治術(shù)和腹腔鏡下胃癌根治術(shù)是腹腔鏡手術(shù)中的新進展，具有對患者

11、創(chuàng)傷小，以及恢復(fù)快的優(yōu)點。在臨床中越來越多地被采用。但是，腹腔鏡直腸癌根治術(shù)和腹腔鏡胃癌根治術(shù)與腹腔鏡膽囊切除術(shù)等短小手術(shù)不同，前者需要建立長時間氣腹并且手術(shù)創(chuàng)面更加廣泛，這會加劇二氧化碳吸收入血的程度，血中二氧化碳分壓升高，超過機體呼吸代償能力，最終產(chǎn)生酸中毒，并且血中二氧化碳分壓的增加還會增加機體的應(yīng)激反響，升高血壓，增加外周血管阻力，以及患者的心肌氧耗【3，4】。因此在這類手術(shù)中需要準確判斷血中二氧化碳分壓，并通過各種措施及時處理，維持血液二氧化碳分壓在正常生理范圍，防止其過度升高產(chǎn)生的諸多不良反響。目前血液二氧化碳分壓監(jiān)測方法主要有無創(chuàng)與有創(chuàng)兩種方式。前者使用較多的是呼氣末二氧化碳分壓

12、和經(jīng)皮二氧化碳分壓監(jiān)測兩種，后者是血氣分析。三種監(jiān)測方式各有臨床優(yōu)缺點。PetCO2通常用于氣管插管行機械通氣的患者，簡便有效，但是對于呼吸和循環(huán)功能改變的患者，其有效性降低；TcPCO2同樣具有簡便、有效、易重復(fù)的特點，但是由于監(jiān)測探頭通常在加熱到42左右的環(huán)境中才能獲得可靠數(shù)據(jù)，因此在開始工作時耗時增加，需要一段數(shù)據(jù)穩(wěn)定期。血氣分析是血液二氧化碳分壓監(jiān)測的金標準，是臨床制定醫(yī)療方案的重要依據(jù)，但是其作為一種有創(chuàng)監(jiān)測，對患者存在一定的傷害性，并且難以連續(xù)觀察，費用高也限制了其在臨床上的廣泛使用。因此尋找到一種無創(chuàng)性監(jiān)測手段客觀有效地反映動脈血二氧化碳分壓的變化具有重要的臨床意義【5，6】。本

13、研究通過比擬TcPCO2，PetCO2和PaCO2三者之間的關(guān)系，發(fā)現(xiàn)對于長時間氣腹手術(shù)TcPCO2與PetCO2的相關(guān)性和一致性更好，尤其是氣腹60min依然保持上述特點。TcPCO2與PaCO2的良好相關(guān)性主要是因為TcPCO2一方面經(jīng)歷了較長時間的數(shù)據(jù)平衡期，同時也是因為其工作時，能夠保證被測皮膚溫度的持續(xù)恒定，因而不易受到外界因素的干擾。而PetCO2對于PaCO2相關(guān)性降低的原因是由于長時間氣腹造成CO2產(chǎn)量增加，同時這類手術(shù)在機械通氣時都會調(diào)整呼吸頻率和潮氣量，從而影響了PetCO2數(shù)值的真實性，此外，CO2氣腹導(dǎo)致的循環(huán)波動也是PetCO2與PaCO2差距增加的重要原因，這在長時

14、間氣腹氣腹30min和氣腹60min時表現(xiàn)更加明顯，因此這類手術(shù)中，PetCO2更易收到其他因素的干擾，因而評估PaCO2的效能也就相應(yīng)的減弱了。本研究在采集樣本時根據(jù)二氧化碳吸收速度規(guī)律選取了三個時間點：根底值為氣腹之前，氣腹30min為二氧化碳分壓上升到達最高速度的時間點【7】，而氣腹60min為二氧化碳穩(wěn)定上升點，因而這三個時間點更能夠客觀有效地反映三個指標之間的關(guān)系。在根底階段，TcPCO2與PaCO2的數(shù)據(jù)相關(guān)性不是很好，r0.57，這可能是15min的平衡時間對于有些患者的TcPCO2監(jiān)測而言相對較短。因此也有學(xué)者建議建議平衡時間為30min。本研究在比擬三個指標之間的一致性差異時

15、使用了BlandAltman分析方法，通過橫坐標為兩種監(jiān)測方法數(shù)值和的一半，而縱坐標為兩種監(jiān)測方法數(shù)值之差，形成散點圖，如果散點分布范圍較集中且在縱坐標0的附近，那么這兩種方法一致性比擬好。此外，在比擬兩種方法一致性的時候，還設(shè)定兩種監(jiān)測數(shù)值差值絕對值不大于3mmHg為臨床允許的正常誤差范圍，也有文獻將該差值定義為0.7kPa【8，9】。通過這兩個統(tǒng)計學(xué)方法，能夠直接形象地發(fā)現(xiàn)TcPCO2和PetCO2與PaCO2一致性的差異。雖然PetCO2與PaCO2總體相關(guān)，但是其散點圖中大多數(shù)的PetCO2都位于允許范圍之外，提示PetCO2與PaCO2的一致性較差。因此，對于相關(guān)性好的兩種指標，其一

16、致性不一定好，相關(guān)性與一致性是兩種不同的概念。由于腹腔鏡直腸癌根治術(shù)和腹腔鏡胃癌根治術(shù)的氣腹時間多在2h內(nèi)完成，因此本研究觀察時間只是限定在氣腹60min，對于更長時間的氣腹手術(shù)，TcPCO2是否還能夠維持對PaCO2預(yù)測的可靠和有效性，這需要進一步的實驗研究?？傊狙芯客ㄟ^比擬TcPCO2和PetCO2對應(yīng)PaCO2的相關(guān)性和一致性分析，發(fā)現(xiàn)TcPCO2與PaCO2相關(guān)性和一致性更好。TcPCO2更加適合于長時間腹腔鏡手術(shù)患者動脈血二氧化碳分壓數(shù)值和變化趨勢的臨床預(yù)測。參考文獻佘守章，岳云主編，臨床監(jiān)測學(xué)，人民衛(wèi)生出版社，第一版，北京：178Oshibuchi M, Cho S, Hara

17、 T, et al. A comparative evaluation of transcutaneous and end-tidal measurements of CO2 in thoracic anesthesia. Anesth Analg2003, 97: 776779Kitano S, Shiraishi N. Minimally invasive surgery for gastric tumors. Surg Clin North Am, 2005, 85: 151-164Hofer CK, Zalunardo MP, Klaghofer R, et al. Changes i

18、n intrathoracic blood volume associated with pneumoperitoneum and position. Acta Anaesthesiol Scand, 2002, 46: 303-308 Andrea C, Grazia S. Giulia M, et al. Transcutaneous monitoring of partial pressure of carbon dioxide in the elderly patient: a prospective, clinical comparison with end- tidal monit

19、oring. Journal of Clinical Anesthesia, 2006, 18: 436-440Bhavani-Shankar K, Steinbrook RA, Mushlin PS, et al. Transcutaneous PCO2 monitoring during laparoscopic cholecystectomy in pregnancy. Can J Anaesth, 1998, 45: 1640169Bozkurt P, Kaya G, Yeker Y, et al. The caradiorespiratory effects of laparosco

20、pic procedures in infants. Anestheseia, 1999, 54: 831-834Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet, 1986, 1: 307-310Tingay DG, Stewart MJ, Morley CJ. Monitoring of end tidal carbon dioxide and transcutaneous carbon dioxide du

21、ring neonatal transport. Arch Dis Child Fetal Neonata Ed, 2005, 90: F523-F526 圖 1： TcPCO2和PetCO2分別與PaCO2相關(guān)的散點圖和直線回歸方程。圖 2 ：通過BlandAltman法評價TcPCO2、PetCO2分別與PaCO2數(shù)據(jù)之間的一致性Predictive effect of transcutaneous carbon dioxide pressure monitoring to the artery carbon dioxide pressure of patients undergoing

22、prolonged laparoscopic surgery. Wu Xiaowen1, Jin Jue1, Yu Buwei1，Zheng Minhua21Department of Anesthesiology, 2Shanghai Minimally Invasive Surgery Center, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.Abstract Objective To evaluate the effects of transcutane

23、ous carbon dioxide pressure (TcPCO2) monitoring in predicting the artery carbon dioxide pressure (PaCO2) of patients undergoing prolonged laparoscopic surgery by the comparison of TcPCO2, end-tidal carbon dioxide pressure (PetCO2), and PaCO2. Methods Sixteen patients, ASA ,scheduled to the laparosco

24、pic radical gastrectomy or proctectomy, were anesthetized with 2.0ug/ml of propofol and 6% of desflurane, TcPCO2, PetCO2, and PaCO2 monitoring were established, while, their values were recorded at three different time points as baseline, 30min after pneumoperitoneum, and 60min after pneumoperitoneu

25、m, respectively. Results Forty-eight sample sets were achieved from these 16 patients, TcPCO2 and PetCO2 had the significant correlations with PaCO2 (rTcPCO2PaCO20.84, p0.05, and rPetCO2PaCO20.75, p0.05). TcPCO2 was still correlated with PaCO2 at time point as baseline, 30min and 60min after pneumop

26、eritoneum, but PetCO2 correlated with PaCO2 only at baseline. The samples rate of the absolute difference between TcPO2 and PaCO2 lower than 3mmHg was 62%, while the samples rate of the absolute difference between PetCO2 and PaCO2 lower than 3mmHg was only 8% (P0.05). Conclusions TcPO2 has a propert

27、y of better correlation and consistence with PaCO2, and it can be used effectively in prediction the values and trends of PaCO2 changes of patients undergoing prolonged laparoscopic surgery.Key Words: transcutaneous carbon dioxide pressure, end-tidal carbon dioxide pressure, artery carbon dioxide pr

28、essure, laparoscopic surgeryArterial partial pressure of carbon dioxide (PaCO2) is one of the most important vital parameters, it mainly reflects the efficiency of lung ventilation and the blood acid-alkali balance, however, the clinical measurement of PaCO2 is complicated because of the arterial pu

29、ncture and blood gas analysis. The measurement of PaCO2 have been substituted by some noninvasive predictions, while, the end-tidal carbon dioxide pressure (PetCO2).monitoring is the ordinary one, its values is usually used to estimate PaCO2 because of their good correlation in the common circumstan

30、ces. But this indirect evaluation is unreliable when patients respiratory or mechanical ventilation models are changed greatly such as high frequency ventilation or the ratio between alveolar ventilation and perfusion is abnormal, rapidly increasing of carbon dioxide (CO2) production accounts for th

31、is unreliability either.1 Finding the new noninvasive methods to evaluate PaCO2 accurately has been focused in the clinical researches. Transcutaneous carbon dioxide (TcPCO2) measurement is a new, noninvasive system using a modified pH-sensitive glass electrode applied to the ear lobe, and has been

32、shown to have a good correlation with PaCO2 in children.2With the developments of surgery techniques, laparoscopic radical gastrectomy or proctectomy for gastric or rectal cancer have been adopted by clinic recently, they have the benefits of minimal invasiveness, less pain, and faster recovery, whi

33、le they also need a long time of CO2 infusion, this prolonged pneumoperitoneum may produce the CO2 accumulation, ventilation models changes, and the decreases of ratios between ventilation and perfusion, then result to the enlargements of differences between PaCO2 and PetCO2 measurements.3 However,

34、the predictive effects of TcPCO2 monitoring for PaCO2 measurement has not been investigated, so we designed this study to evaluate the accuracy of estimation of PaCO2 by TcPCO2 monitoring in the patients undergoing prolonged laparoscopic surgeries. Materials and MethodsThis study was approved by the

35、 institutional ethics committee of Ruijin Hospital. After written informed consent, sixteen patients scheduled to undergo laparoscopic radical gastrectomy or proctectomy were enrolled , all patients were ASA or stage, while, patients with severe cardiovascular diseases or respiratory diseases were e

36、xcluded in this study. On arrival at the operation room, all patients were monitored with the standard procedures, such as ECG, SpO2, and NIBP monitors (AS/5 monitor (DatexOhmed, Fanland), then a 18-gauge intravenous catheters was placed in the peripheral veins for fluid transfusion. General anesthe

37、sia was induced with propofol 4 ug/ml as target concentration infusion (TCI), fentanyl 2 ug/kg, and atracurium 0.6mg/kg, then trachea was intubated and lungs were mechanically ventilated by 2 L/min of oxygen, tidal volume and respiratory rate were adjusted to maintain PetCO2 ranged within 35-45 mmHg

38、. Anesthesia was maintained by 2 ug/ml of TCI propofol, combined with desoflurane 6% inhalation, fentanyl and actracurium were infused intermittently as necessary. Arterial blood pressure and heart rates ranged within 20% of the baseline values during the operation.Transcutaneous CO2 partial pressur

39、e was measured with a TcPCO2 monitoring system (SenTec Digital Monitor, SenTec Inc. Switzerland), before measurement, the TcPCO2 electrode was cleaned and a new member applied, as well as the patients ear lobes were scraped with alcohol, then the electrode was calibrated with a calibration gas suppl

40、y according to manufactures instructions, After 15min applied the transcutaneous sensor at the ear lobe, the TcPCO2 values were stable, then the laparoscopic surgery was started, and the pneumoperitoneum was established. The baseline values of TcPCO2 were recorded at the time between the stabilized

41、of TcPCO2 measurement and the beginning of pneumoperitoneum, while, PaCO2 and PetCO2 were measured and recorded at the same time. PaCO2 measurement from the arterial blood sample was determined using i-STAT Analyzer System, Analyzer performance was calibrated daily and before each sample analysis. T

42、he disposable EG7+ cartridges were verified for calibration, while, PetCO2 was measured by the AS/5 monitor (DatexOhmed, Fanland) and calibrated before measurement, either. These three values were termed as the baseline. After 30min and 60min of pneumoperitoneum, patients parameters as TcPCO2, PaCO2

43、, and PerCO2 were measured simul, respectively. The intraperitoneal CO2 infusion pressure during the operation was maintained at 14mmHg.Data were presented as meansSD. Statistical analysis was performed using the software of SPSS13.0 for windows, the correlation between PaCO2 and both PetCO2 and TcP

44、CO2 measurements was analyzed by Pearson correlation and liner regression analysis, whereas the Bland-Altman method was used to assess the agreement between arterial and both end-tidal and transcutaneous CO2 values. We considered a difference of 3 mmHg between the PaCO2 and the noninvasive measureme

45、nt as a clinically acceptable range to determine whether the two compared methods were interchangeable. X2 analysis was also used to compare the number of PetCO2 versus TcPCO2 values whose absolute difference deviated from 3 mmHg or less of PaCO2. P value0.05 was considered statistically significant

46、.ResultsSixteen patients were enrolled in this investigation, while, half of them were male and the others were female. The patients age averaged 6511 ys44 ys86 ys, and the patients weight averaged 6311 kg4379 kg, 11 patients were scheduled to undergo laparoscopic proctectomy, and the others were ra

47、dical gastrectomy.Three sample sets (PaCO2, PetCO2, and TcPCO2) were obtained from the 16 patients at three different time points and resulted to a total of 48 sample sets. Among these samples, both TcPCO2 and PetCO2 had the significant correlation with PaCO2 (the linear regression equations were Pa

48、CO2=0.96TcPCO2+2.92, r2=0.71, p0.01, and PaCO2=0.53PetCO2+13.055, r2=0.555, p0.01). In respect of the three different time points, TcPCO2 correlated well with PaCO2 not only at baseline, but also at the 30 min and 60 min of pneumoperitoneum , the coefficients of correlation between them were 0.57, 0

49、.83, and 0.74, respectively (p0.05). however PetCO2 correlated with PaCO2 only at the baseline (r=0.55, p0.05). Fig 1According to results of Bland-Altman analysis, the mean bias between PaCO2 and TcPCO2 (PaCO2TcPCO2) was 13mmHg, whereas the mean bias between PaCO2 and PetCO2 (PaCO2PetCO2) was 84mmHg

50、. The absolute value of the difference between PaCO2 and TcPCO2 was 3 mmHg or less in 30 (62%) of 48 sample sets, while, the absolute value of the difference between PaCO2 and PetCO2 was 3 mmHg or less in 4 (8%) of 48 sample sets (p0.05).Fig 2Discussion The results of this study shows that TcPCO2 mo

51、nitoring reflects more accurately of PaCO2 than PetCO2 monitoring during the period of penumoperitoneum when patients are undergoing prolonged laparoscopic surgeries such as radical gastrectomy and proctectomy.Laparoscopic radical gastrectomy or protectomy are the achievements of laparoscopic surger

52、ys progression. They can provide several benefits for the patients, including minimally invasion, less pain, less inflammatory, faster recovery, and shorter hospital stay, so the clinical adoption of these new surgery procedures is increasing nowadays. Besides the advantages mentioned above, and com

53、pared with the classical laparoscopic cholecystotomy, laparoscopic radical gastrectomy and protectomy have the features as long-term of penumoperitoneum and more extensive trauma, they will aggravate the extents of carbon dioxide absorbed into blood, and the accumulation of CO2 contents. Moreover, t

54、he rapid increasing of PaCO2 termed as hypercapnia produces sympathoexcitation which increases cardiac output, enhances blood pressure and systemic vascular resistance, and aggravates the oxygen consume of patients cardiac, besides the academia as the common results of hypercapnia.3,4 One aim of the

55、 anesthesia managements during these operations is set to maintain the normal partial pressure of CO2 in the blood and avoid the side effects of hypercapnia.Efficient monitoring of PaCO2 is the first stage to keep the normal ranges of PaCO2. The methods of monitoring of PaCO2 are divided into invasi

56、ve and noninvasive ways. The former is the blood gas analysis, and the later includes PetCO2 and TcPCO2 measurements. PetCO2 is applicable to the tracheal intubated patients, but will not correlate well with PaCO2 when patients circulatory or respiratory functions changed significantly. TcPCO2 monit

57、oring can reflect PaCO2 changes simply, accurately, and reliably, while, the period to obtain the stable values of TcPCO2 is slightly long, because its necessary to heat the sensor to 42 to get the stable data. Blood gas analysis is the standard method of PaCO2 assessment. But this invasive techniqu

58、e requires sophisticated surgical maneuvers. Furthermore, the pain and volume blood loss associated with the surgery affects the accuracy of the PaCO2 measurements, blood gas analysis can not monitor PaCO2 continually, the high cost of blood gas analysis limits its measurement. So the use of more re

59、liable and accurate noninvasive method to estimate PaCO2 value is the goal of clinical research.5,6In this study, we compare the relationships among TcPCO2, PetCO2 and PaCO2, find that TcPCO2 correlated with PaCO2 is more accurate than that between PetCO2 and PaCO2 during the prolonged laparoscopic

60、surgery, especially at the time point of 60min after penumoperitoneum. A long period of stable data obtained and the sensor located skins temperature kept constant may account for the good correlation between TcPCO2 and PaCO2. The reasons of the gradually decrease of correlation between PetCO2 and P