Enderson B L, Rice C, Moss G S
J Surg Res. 1985 Mar;38(3):224-30. doi: 10.1016/0022-4804(85)90030-7.
The thermal-dye indicator dilution technique of measuring extravascular lung water (EVLW-TD) correlates well with gravimetric measurement of lung water (EVLW-GR) when no positive-end expiratory pressure (PEEP) is used in both normal and edematous lungs. PEEP is often used to raise arterial oxygen tension in acute respiratory failure. This study was designed to answer the question: Does PEEP have an effect on the accuracy of the EVLW measurement by thermal dye? Sixteen mongrel dogs were anesthetized and intubated. Arterial and PA catheters were placed. They were divided into three groups and ventilated at PEEP levels of 5, 10, or 15 cm H2O. Fluids were given to minimize decrease in cardiac output with institution of PEEP. They were maintained for 5 hr with measurement of vital signs made hourly and measurement of blood gases and EVLW-TD made at baseline, 1, 3, and 5 hr. After final measurements, gravimetric determination of EVLW was done. Correlation between EVLWTD and EVLWGR remained good when low levels of PEEP were used. At 5 cm H2O PEEP, EVLWTD was 7.5 +/- 0.9 and EVLWGR was 5.4 +/- .3. At 10 cm H2O PEEP, they were 10.0 +/- 0.9 and 6.5 +/- 0.3. The correlations were 0.87 and 0.97, respectively. However, at 15 cm H2O PEEP, EVLWTD was 11.4 +/- 1.3 and EVLWGR was 7.5 +/- 0.6, with a correlation of only 0.59. The correlation between the two techniques seems to break down with higher levels of PEEP in dogs with normal lungs.
在正常肺和水肿肺中，当不使用呼气末正压（PEEP）时，热染料指示剂稀释技术测量血管外肺水（EVLW - TD）与肺水重量测量法（EVLW - GR）具有良好的相关性。PEEP常用于提高急性呼吸衰竭患者的动脉血氧张力。本研究旨在回答以下问题：PEEP对热染料法测量EVLW的准确性是否有影响？16只杂种犬麻醉后插管，置入动脉导管和肺动脉导管。将它们分为三组，分别在5、10或15 cm H₂O的PEEP水平下通气。给予液体以尽量减少因PEEP的应用导致的心输出量下降。维持5小时，每小时测量生命体征，在基线、1小时、3小时和5小时测量血气和EVLW - TD。最终测量后，进行EVLW的重量测定。当使用低水平的PEEP时，EVLWTD与EVLWGR之间的相关性仍然良好。在5 cm H₂O PEEP时，EVLWTD为7.5±0.9，EVLWGR为5.4±0.3。在10 cm H₂O PEEP时，它们分别为10.0±0.9和6.5±0.3。相关性分别为0.87和0.97。然而，在15 cm H₂O PEEP时，EVLWTD为11.4±1.3，EVLWGR为7.5±0.6，相关性仅为0.59。在正常肺的犬中，随着PEEP水平升高，这两种技术之间的相关性似乎减弱。
