摘要:目的: 評價機械通氣對胸腔內脈搏氧飽和度的影響。 方法 :以食道、氣管和降主動脈作為胸腔內脈搏氧飽和度的監測位點,將改制后的氧飽和度探頭分別固定于上述部位,并連接于同一監護儀上。純氧通氣,待上述氧飽和度容積波波形和讀數穩定,停止機械通氣30s。以錄像的方式記錄機械通氣停止前后30 s內食道、氣管和降主動脈SpO2容積波和讀數的變化。同時記錄舌SpO2。 結果 :機械通氣時,食道、氣管和降主動脈三個監測位點均可獲得異常高大的SpO2容積波;停止通氣時,異常高大的氧飽和度波形消失。食道、氣管和降主動脈脈搏容積波變異率分別為112%,74%,302%。降主動脈脈搏容積波的變異率明顯高于食道和氣管( 〖WTBX〗P ＜005)。機械通氣停止前后30s內食道、氣管和降主動脈的SpO2讀數變化無顯著差異(〖WTBX〗P ＞005)。 結論 :機械通氣對胸腔內食道、氣管和降主動脈氧飽和度讀數無影響,主要影響是脈搏容積波。且各位點間脈搏氧容積波受呼吸的影響不同。
Abstract: Objective: To investigate the impact of mechanical ventilation on pulse oximetry in thoracic cavity. Methods : After dogs anesthesia induction and thoracotomy, pulse oximeters were simultaneously placed at esophagus, trachea, and descending aorta, and connected with the same monitor for SpO2 monitoring. During ventilation with 100% oxygen, the mechanical ventilator was temporarily switched off for 30 seconds after high quality PPG waveforms and SpO2 readings were obtained. SpO2 signals and readings from esophagus (SeO2), trachea (StraO2), descending aorta (SDAO2) shown on the monitoring screen were recorded by the SONY video before and after stopventilation. And StonO2 were also recorded. Results : Abnormally largeamplitude PPG waves were found in normal waves at monitoring sites of esophagus, trachea, and descending aorta in all animals during ventilation; however, they disappeared without ventilator. The variation rate in ventilationinduced PPG amplitude were 112%, 74%, 302% at esophagus, trachea and descending aorta respectively. The PPG amplitude variation rate from SDAO2 was higher than that from SeO2 and StraO2 (〖WTBX〗P ＜005). However, the SpO2 readings obtained from pulse oximetries in all sites were no significantly statistical difference within 30s before and after temporarily stopventilation (〖WTBX〗P ＞005). Conclusion : Abnormally amplitude PPG waveforms from oximetry probe placed at esophagus, trachea, and descending aorta were induced by ventilation. The Variation rate in ventilationinduced PPG amplitude was various at different monitoring sites. The SpO2 readings from esophagus, trachea, and descending aorta were not significantly contaminated by ventilation.
Citation： LI Shuping ,WANG Li,MU Lin,WEI Wei.. The Impact of Mechanical Ventilation on Pulse Oximetry in Thoracic Cavity. West China Medical Journal, 2009, 24(10): 2551-. doi: Copy
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