Rossi Patrik, Wanecek Michael, Rudehill Anders, Konrad David, Weitzberg Eddie, Oldner Anders
Department of Physiology and Pharmacology, Section of Anaesthesiology & Intensive Care Medicine, Karolinska Institute, Stockholm, Sweden.
Crit Care Med. 2006 May;34(5):1437-43. doi: 10.1097/01.CCM.0000215830.48977.29.
To compare the single thermal indicator dilution (STID) technique for measurement of extravascular lung water (EVLW(STID)) with gravimetrically determined EVLW (EVLW(GRAV)) in anesthetized pigs under sham and endotoxemic conditions.
Open experimental comparative animal study.
University animal research laboratory.
Fifteen anesthetized landrace pigs.
Endotoxin infusion during 5 hrs in five pigs. Six animals were only anesthetized and rested for 5 hrs. In four additional animals, the impact on EVLW(STID) measurements by changes in pulmonary perfusion, ventilation, and the combination of the two was studied. The alterations in ventilation and perfusion were induced by caval balloon inflation, inflation of the pulmonary artery catheter balloon, and bronchial plugging respectively.
The STID technique, with default settings of the intrathoracic blood volume (ITBV) to global end-diastolic volume (GEDV) (i.e., the extrapulmonary intravascular volume between the point of injection of the indicator, and the point of detection) relationship (ITBV = 1.25GEDV), systematically overestimated the EVLW index compared with the gravimetrical method (mean bias of 5.4 mL/kg). By adapting the ITBV to GEDV relationship to the current model (ITBV = 1.52GEDV + 49.7), the accuracy of the STID technique improved. Moreover, the measurement of EVLW(STID) proved to be reduced by manipulation of pulmonary perfusion and ventilation. However, the STID technique could detect an increase in EVLW during endotoxemia independent of the ITBV/GEDV relationship used.
Despite technological improvement, the dilution techniques for the measurement of EVLW might still be influenced by changes in perfusion and ventilation. The STID technique, in addition, might demand adjustment of the ITBV/GEDV relationship to the particular condition and species subjected to measurement. The STID technique may, however, be a useful tool for monitoring changes of EVLW over time, but further studies are warranted to confirm this.
比较单热指示剂稀释（STID）技术与重量法测定的血管外肺水（EVLW），以评估在假手术和内毒素血症条件下麻醉猪的血管外肺水（EVLW(STID)）。
开放性实验对比动物研究。
大学动物研究实验室。
15只麻醉的长白猪。
5只猪内毒素输注5小时。6只动物仅麻醉并休息5小时。另外4只动物研究了肺灌注、通气及两者联合变化对EVLW(STID)测量的影响。通气和灌注的改变分别通过腔静脉球囊充气、肺动脉导管球囊充气和支气管堵塞诱导。
STID技术采用默认的胸腔内血容量（ITBV）与全心舒张末期容积（GEDV）（即指示剂注射点与检测点之间的肺外血管内容积）关系（ITBV = 1.25GEDV）时，与重量法相比，系统性高估了EVLW指数（平均偏差为5.4 mL/kg）。通过将ITBV与GEDV关系调整为当前模型（ITBV = 1.52GEDV + 49.7），STID技术的准确性得到提高。此外，肺灌注和通气的操作证明会降低EVLW(STID)的测量值。然而，无论使用何种ITBV/GEDV关系，STID技术都能检测到内毒素血症期间EVLW的增加。
尽管技术有所改进，但用于测量EVLW的稀释技术仍可能受灌注和通气变化的影响。此外，STID技术可能需要根据特定测量条件和物种调整ITBV/GEDV关系。不过，STID技术可能是监测EVLW随时间变化的有用工具，但需要进一步研究加以证实。
