呼氣末二氧化碳在急診的臨床應(yīng)用2

1、北京協(xié)和醫(yī)院急診科北京協(xié)和醫(yī)院急診科 談定玉談定玉 第六生命體征概述 呼氣末二氧化碳（呼氣末二氧化碳（ end-tidal carbon dioxide ，ETCOETCO2 2)是指是指呼氣終末期呼出的呼氣終末期呼出的混合肺泡氣含有的二氧化碳分壓混合肺泡氣含有的二氧化碳分壓（ P PETETCOCO2 2) )或濃度（或濃度（C CETETCOCO2 2 ) )值值 無創(chuàng)、連續(xù)、實(shí)時(shí)、簡便、重要無創(chuàng)、連續(xù)、實(shí)時(shí)、簡便、重要體內(nèi)體內(nèi)CO2產(chǎn)量產(chǎn)量(VCO2)和肺通氣量和肺通氣量(VA)決定決定PACO2PACO2= VCO2 0.863/VA, 0.863為氣體容量轉(zhuǎn)換為壓力的系數(shù)為氣體容量轉(zhuǎn)

2、換為壓力的系數(shù)正常人正常人PETCO2 PACO2 PaCO2（正常通氣血流比例），（正常通氣血流比例）， PETCO2略低于略低于PaCO2PaCO2 ，差值小于，差值小于5mmHgPETCO2和和 Pa CO2受到受到 CO2產(chǎn)量產(chǎn)量、肺泡通氣量肺泡通氣量和和肺血流灌注量肺血流灌注量影響影響 PETCO2監(jiān)測的方法質(zhì)譜儀法質(zhì)譜儀法：反應(yīng)快，能連續(xù)監(jiān)測，但儀器價(jià)格昂貴，難以在臨反應(yīng)快，能連續(xù)監(jiān)測，但儀器價(jià)格昂貴，難以在臨床廣泛應(yīng)用床廣泛應(yīng)用比色法比色法：簡便有用，但精確性欠佳簡便有用，但精確性欠佳紅外線監(jiān)測法：紅外線監(jiān)測法： CO2僅對(duì)波長僅對(duì)波長4.26微米的紅外線微米的紅外線才有強(qiáng)烈的吸

3、才有強(qiáng)烈的吸收作用。流經(jīng)的收作用。流經(jīng)的 CO2吸收掉一部分紅外線能量，吸收的多少與吸收掉一部分紅外線能量，吸收的多少與 CO2濃度成比例關(guān)系。經(jīng)過微電腦處理獲得濃度成比例關(guān)系。經(jīng)過微電腦處理獲得PET CO2 。 主流型主流型 旁流型旁流型主流和旁流區(qū)別PETCO2與PaCO2的一致性Ebrahim Razi, et. Arch Trauma Res. 2012;1(2):58-62. McSwain SD,et al. Respir Care. 2010 ; 55(3): 288293.旁流Nonintubated patients with dyspnea ( 18 years) in

4、an ED38% had a difference of 10 mm Hg or more. The mean difference between the PaCO2 and ETCO2 levels was 8 mm HgDelerme S, et al.Am J Emerg Med. 2010 ;28(6):711-4. 正常ETCO2波形 正常人的正常人的ETCO2 值范圍值范圍 32-43相相： 吸氣基線，處于零點(diǎn)，是呼氣的開始部分吸氣基線，處于零點(diǎn)，是呼氣的開始部分相相： 呼氣上升支，為肺泡和無效腔的混合氣呼氣上升支，為肺泡和無效腔的混合氣相相： 呼氣平臺(tái)，呈水平形，是混合呼氣平臺(tái)

5、，呈水平形，是混合肺泡氣肺泡氣相相： 呼氣下降支，迅速而陡直下降至基線，新鮮氣體進(jìn)入氣道呼氣下降支，迅速而陡直下降至基線，新鮮氣體進(jìn)入氣道ETCO2觀察指標(biāo)基線：基線：代表吸入代表吸入CO2濃度濃度高度：高度：代表呼出代表呼出CO2的濃度的濃度形態(tài)：形態(tài)：正常正常CO2波形與不正常波形波形與不正常波形頻率：頻率：反映呼吸頻率反映呼吸頻率節(jié)律：節(jié)律：反映呼吸中樞或呼吸機(jī)的設(shè)置反映呼吸中樞或呼吸機(jī)的設(shè)置影響ETCO2因素 機(jī)體因素機(jī)體因素：影響影響CO2產(chǎn)生：體溫、代謝、藥物等產(chǎn)生：體溫、代謝、藥物等影響影響CO2運(yùn)輸：心輸出、肺灌注運(yùn)輸：心輸出、肺灌注影響通氣：阻塞性及限制性肺疾病，呼吸頻率影響

6、通氣：阻塞性及限制性肺疾病，呼吸頻率通氣血流比例變化通氣血流比例變化 設(shè)備因素設(shè)備因素：呼吸機(jī)設(shè)置、故障，管道脫落、阻塞及漏氣呼吸機(jī)設(shè)置、故障，管道脫落、阻塞及漏氣取樣管堵塞，取樣部位及速率取樣管堵塞，取樣部位及速率ETCO2常見異常波形常見異常波形ETCO2急診應(yīng)用常見異常波形代謝代謝：體溫降低：體溫降低循環(huán)循環(huán)：全身或肺灌注降低（：全身或肺灌注降低（PE、shock，嚴(yán)重時(shí)會(huì)突然降低），嚴(yán)重時(shí)會(huì)突然降低）通氣通氣：分鐘通氣量增大，過度通氣：分鐘通氣量增大，過度通氣儀器儀器：漏氣、取樣管故障等：漏氣、取樣管故障等代謝代謝：體溫升高，寒顫，抽搐：體溫升高，寒顫，抽搐循環(huán)循環(huán)：心輸出量增加，輸入

7、碳酸氫鈉，缺血肢體血供恢復(fù)：心輸出量增加，輸入碳酸氫鈉，缺血肢體血供恢復(fù)通氣通氣：分鐘通氣量降低，通氣不足：分鐘通氣量降低，通氣不足儀器儀器：呼吸機(jī)活瓣故障：呼吸機(jī)活瓣故障Loss of Waveform呼吸驟停呼吸驟停窒息窒息人工氣道脫落或阻塞人工氣道脫落或阻塞CO2儀器故障儀器故障采樣管堵塞扭曲采樣管堵塞扭曲Howe TA, et al. J Emerg Med. 2011;41(6):581-9.Loss of Alveolar Plateau支氣管痙攣支氣管痙攣哮喘哮喘AECOPD氣道阻塞氣道阻塞痰液痰液呼吸回路的呼氣段阻塞呼吸回路的呼氣段阻塞氣管插管或螺紋管部分阻塞或打折氣管插管或螺

8、紋管部分阻塞或打折shark finningElevated Baseline不完全吸氣或呼氣不完全吸氣或呼氣 回路內(nèi)部分重吸入回路內(nèi)部分重吸入哮喘或者哮喘或者COPD的病人氣體受阻的病人氣體受阻呼氣時(shí)間不足呼氣時(shí)間不足球囊通氣呼氣期或呼吸機(jī)出現(xiàn)故障球囊通氣呼氣期或呼吸機(jī)出現(xiàn)故障校準(zhǔn)有誤校準(zhǔn)有誤延長呼氣時(shí)間延長呼氣時(shí)間EtCO2 decreases as exhalation continues, CO2 is not reaching the detector. 氣囊漏氣tube that is too small自主呼吸恢復(fù)自主呼吸恢復(fù)肌松作用消失肌松作用消失肺泡死腔增大吸氣流速降低ETC

9、O2急診臨床應(yīng)用急診臨床應(yīng)用ETCO2急診應(yīng)用心肺復(fù)蘇 提示心跳驟停提示心跳驟停 指導(dǎo)復(fù)蘇指導(dǎo)復(fù)蘇按壓質(zhì)量按壓質(zhì)量 提示提示ROSC 預(yù)后意義預(yù)后意義按壓深度與ETCO2Sheak KR.et al. Resuscitation. 2015;89:149-54. PETCO2突然大于突然大于40mmHg提示提示ROSCETCO2與ROSC2010指南指南： PETCO210mmHg設(shè)法改進(jìn)設(shè)法改進(jìn)CPR質(zhì)量質(zhì)量復(fù)蘇成功者復(fù)蘇成功者PETCO2明顯高于復(fù)蘇失敗者明顯高于復(fù)蘇失敗者PETCO2持續(xù)持續(xù) 16 mmHg were significantly associated with survi

10、val from emergency department resuscitation. No patient survived with a level 16 mm HgHartmann SM, et al. J Intensive Care Med.2014 Apr 22. Epub ahead of printETCO2與預(yù)后 Retrospective observational study 16542 cardiac arrest patients admitted to 125 Australia and New Zealand ICUs between 2000 and 2011

11、 PaCO2 97% on 2 - 4 L/min of oxygen. More sensitive than pulse oximetry in predicting a trend toward respiratory failure Abramo TJ. Crit Care Med 1997;25:12426. 提前預(yù)警缺氧提前預(yù)警缺氧 132 adults underwent sedation with propofol in the ED. All patients received supplemental oxygen at 3 L/min. Capnography gave

12、advanced warning for all hypoxic events (SpO 2 93% for 15 s). A median time of 60s demonstrated capnographic evidence of respiratory depression before hypoxia.Ann Emerg Med. 2010;55:258-264.旁流型旁流型ETCO2急診應(yīng)用-圍插管期監(jiān)測插管時(shí) 目前公認(rèn)證明氣管導(dǎo)管在氣管內(nèi)的正確方法有三種：目前公認(rèn)證明氣管導(dǎo)管在氣管內(nèi)的正確方法有三種：1.1.肯定看到導(dǎo)管在聲門內(nèi)肯定看到導(dǎo)管在聲門內(nèi)2.2. 看到看到ETCOE

13、TCO2 2的正常圖形。直觀，反應(yīng)快，操作方便的正常圖形。直觀，反應(yīng)快，操作方便3.3. 利用纖維支氣管鏡技術(shù)是判斷導(dǎo)管位置的利用纖維支氣管鏡技術(shù)是判斷導(dǎo)管位置的“金標(biāo)準(zhǔn)金標(biāo)準(zhǔn)”，但使用不，但使用不便便Esophageal IntubationETCO2急診應(yīng)用-圍插管期監(jiān)測插管后 通氣功能監(jiān)測通氣功能監(jiān)測 指導(dǎo)呼吸機(jī)設(shè)置指導(dǎo)呼吸機(jī)設(shè)置 間接反映循環(huán)功能：及時(shí)識(shí)別插管后低血壓等間接反映循環(huán)功能：及時(shí)識(shí)別插管后低血壓等 在撤機(jī)中的應(yīng)用在撤機(jī)中的應(yīng)用Pellis (2005) J TraumaETCO2急診應(yīng)用休克ETCO2急診應(yīng)用休克Hypovolemic 29.64 11.49 Cardiog

14、enic 28.60 9.87 Septic shock 27.81 7.39ETCO2 on ED arrival is positively correlated with systolic and diastolic BP, MAP, bicarbonate, base excess and lactate.All patients who had ETCO2 12mmHg died in the ED. Kheng. International Journal of Emergency Medicine 2012 5:31.ETCO2急診應(yīng)用容量反應(yīng)性 In stable ventil

15、atory and metabolic conditions, without spontaneous breathing A PLR-induced increasein EtCO2 5 % predicted a fluid-induced increase in CI 15 % with sensitivity of 71 % (95 % confidence interval: 4889 %) and specificity of 100 (82100) %. Intensive Care Med (2013) 39:93100ETCO2急診應(yīng)用肺栓塞ETCO2 decreases s

16、econdary to increase in dead-space ventilation. ETCO2 36 mm Hg had an optimal sensitivity and specificity of 87.2% and 53%, respectively, for identifying patients without PE. A negative predicative value of 96.6% (95% confidence interval CI 92.3 - 98.5) demonstrates the value of this technique. This

17、 increased to 97.6% (99% CI 93.2 99.2) when combined with a Wells score 4Hemnes AR, et al.Eur Respir J 2010;35:73541.AVDSf (mm Hg ) = (PaCO2 - PETCO2)/PaCO2ETCO2急診應(yīng)用肺栓塞The AVDSf value with the highest sensitivity and specificity, which was at the same time statistically significant, was 0.09. The us

18、e of AVDSf in combination with any of the several scoring systems that evaluate clinical likelihood of PE and D-dimer levels resulted in higher sensitivity and specificity rates for the diagnosis of PE.Kurt OK,et al. Am J Emerg Med. 2010;28(4):460-5. ETCO2急診應(yīng)用酮癥 ETCO2 可以持續(xù)實(shí)時(shí)準(zhǔn)確反映PCO2 , 間接反應(yīng)代謝Initial

19、pH values were 7.08, RR was 35 breaths/min, EtCO2 18.6, and venous PCO2 20. pH had improved to 7.29, RR to 22 breaths/min, EtCO2 to 35, and the venous PCO2 to 36.The correlation between ETCO2 and venous PCO 2 was significant (r = 0.92, p = 0.0001) Continuous assessment for trending of clinical valuesGarcia E, et al. Crit Care Med 2003;31:253943.ETCO2急診應(yīng)用ED病人的預(yù)后Sepsis Trauma1088