Zaune U, Knarr C, Krüselmann M, Pauli M H, Boeden G, Martin E
Department of Anesthesiology, Klinikum Nürnberg, West Germany.
J Cardiothorac Anesth. 1990 Aug;4(4):441-52. doi: 10.1016/0888-6296(90)90289-r.
During thoracic surgery, one-lung ventilation (1LV) is often required. The purpose of this prospective study was to examine the usefulness and accuracy of dual-oximetry during 1LV. Prior to the induction of anesthesia, 30 patients had a radial artery and a fiberoptic pulmonary artery catheter (15 Edwards, 15 Spectramed by randomization) inserted. Arterial O2 saturation (SpO2) was monitored by pulse oximetry, and mixed venous O2 saturation (SvO2) by oximetry (Edwards or Spectramed). Arterial and mixed venous blood gases were obtained and immediately analyzed by an OSM3-Hemoximeter. Measurements, including hemodynamics and blood gases, were obtained before induction, during two-lung ventilation (2LV) in the supine and lateral decubitus positions, during 1LV, and following extubation. The change from 2LV to 1LV was associated with significant increases in cardiac index (CI) and oxygen delivery index (DO2I), whereas PaO2 and arterial and mixed venous oxygen saturation decreased. The ratio of oxygen consumption to delivery remained stable. Continuous oximetry when compared with in vitro measurements yielded a correlation coefficient for arterial oxygen saturation of r = 0.794 (P less than or equal to 0.001) and a value of bias and precision of -0.5% +/- 1.7%; for mixed venous oxygen saturation of r = 0.874 (P less than or equal to 0.001) and -1.3% +/- 2.8% for the two-wavelength Edwards catheter; and, r = 0.862 (P less than or equal to 0.001) and -0.1% +/- 3.2% for the two-wavelength Spectramed catheter. These findings demonstrate that dual-oximetry is an on-line, reliable method to measure SpO2 and SvO2. SpO2 less than 95% reflects hypoxygenation and hypoxia (PaO2 less than or equal to 70 mm Hg). SvO2 is determined primarily by oxygenation (r = 0.005; P less than or equal to 0.05) rather than by CI (r = 0.001, ns). Since DO2I increased during 1LV to maintain the oxygen supply and demand balance, SvO2 monitoring might be useful as an early indicator in identifying high-risk patients with compromised DO2I resulting from decreased CI.
在胸外科手术中，常常需要进行单肺通气（1LV）。这项前瞻性研究的目的是检验双血氧测定法在单肺通气期间的实用性和准确性。在麻醉诱导前，30例患者插入了桡动脉导管和纤维光学肺动脉导管（随机分配，15例使用爱德华兹导管，15例使用光谱医疗导管）。通过脉搏血氧测定法监测动脉血氧饱和度（SpO2），通过血氧测定法（爱德华兹或光谱医疗）监测混合静脉血氧饱和度（SvO2）。采集动脉血和混合静脉血样本，立即用OSM3-血液气体分析仪进行分析。在诱导前、仰卧位和侧卧位双肺通气（2LV）期间、单肺通气期间以及拔管后，获取包括血流动力学和血气分析在内的各项测量数据。从双肺通气转变为单肺通气时，心脏指数（CI）和氧输送指数（DO2I）显著增加，而动脉血氧分压（PaO2）以及动脉和混合静脉血氧饱和度降低。氧消耗与输送的比率保持稳定。与体外测量结果相比，连续血氧测定法测得动脉血氧饱和度的相关系数r = 0.794（P≤0.001），偏差和精密度值为-0.5%±1.7%；对于双波长爱德华兹导管，混合静脉血氧饱和度的相关系数r = 0.874（P≤0.001），偏差和精密度值为-1.3%±2.8%；对于双波长光谱医疗导管，相关系数r = 0.862（P≤0.001），偏差和精密度值为-0.1%±3.2%。这些研究结果表明，双血氧测定法是一种在线、可靠的测量SpO2和SvO2的方法。SpO2低于95%反映低氧血症和缺氧（PaO2≤70 mmHg）。SvO2主要由氧合作用决定（r = 0.005；P≤0.05），而非由CI决定（r = 0.001，无统计学意义）。由于在单肺通气期间DO2I增加以维持氧供需平衡，SvO2监测可能作为一种早期指标，用于识别因CI降低导致DO2I受损的高危患者。
