Russell G B, Snider M T, Richard R B, Rutherford T M, Loomis J L
Department of Anesthesia, The Pennsylvania State University College of Medicine, University Park.
J Neurosurg Anesthesiol. 1991 Mar;3(1):56-60. doi: 10.1097/00008506-199103000-00009.
Continuous mixed venous oxygen saturation (SvO 2) was evaluated as a monitor of venous air embolism in a canine model. Nineteen dogs were anesthetized, paralyzed, and mechanically ventilated. Invasive monitoring included SvO 2, systemic and pulmonary artery blood pressures, and thermodilution cardiac outputs. Air boluses of 0.25 and 0.5 ml/kg were injected in six dogs and 1 ml/kg in all. All 1 ml/kg emboli were detected by greater than or equal to 5% decreases in the SvO 2. The SvO 2 decreased from 82 +/- 8% to 72 +/- 11% (mean +/- SD), an average decrease of 9 +/- 5% (p = 0.004). Time to the SvO 2 nadir was 2.6 +/- 2.5 min. Of the 0.5 and 0.25 ml/kg emboli, 50% and 17% were detected, respectively. Cardiac output decreased from 2.9 +/- 0.8 to 2.1 +/- 0.8 L/min after the 1 ml/kg emboli (p = 0.02). The 1 ml/kg emboli increased pulmonary artery pressures and decreased systemic blood pressure in 100% and 75% of animals, respectively. Peak changes in pulmonary artery pressure occurred at 1.2 +/- 0.8 min. In the present study, time to maximum change was greater for SvO 2 than for pulmonary artery pressure changes. Use of fiberoptic pulmonary artery catheters for continuous measurement of SvO 2 can add a new diagnostic modality to venous air embolism detection in patients who require a pulmonary artery catheter for other medical indications.
在犬类模型中，连续混合静脉血氧饱和度（SvO₂）被评估为静脉空气栓塞的一种监测指标。19只犬被麻醉、麻痹并进行机械通气。有创监测包括SvO₂、体循环和肺动脉血压以及热稀释法心输出量。分别对6只犬注射0.25 ml/kg和0.5 ml/kg的空气团注，其余所有犬注射1 ml/kg。所有注射1 ml/kg空气栓子的情况均通过SvO₂下降大于或等于5%被检测到。SvO₂从82±8%降至72±11%（平均值±标准差），平均下降9±5%（p = 0.004）。SvO₂降至最低点的时间为2.6±2.5分钟。0.5 ml/kg和0.25 ml/kg空气栓子的检测率分别为50%和17%。注射1 ml/kg空气栓子后，心输出量从2.9±0.8降至2.1±0.8 L/分钟（p = 0.02）。1 ml/kg空气栓子分别使100%和75%的动物肺动脉压升高和体循环血压降低。肺动脉压的峰值变化出现在1.2±0.8分钟。在本研究中，SvO₂达到最大变化的时间比肺动脉压变化的时间更长。对于因其他医学指征需要肺动脉导管的患者，使用纤维光学肺动脉导管连续测量SvO₂可为静脉空气栓塞的检测增加一种新的诊断方法。
