Sakka S G, Rühl C C, Pfeiffer U J, Beale R, McLuckie A, Reinhart K, Meier-Hellmann A
Department of Anaesthesiology and Intensive Care Medicine, Friedrich-Schiller-University of Jena, Germany.
Intensive Care Med. 2000 Feb;26(2):180-7. doi: 10.1007/s001340050043.
Transpulmonary double-indicator dilution is a useful monitoring technique for measurement of intrathoracic blood volume (ITBV) and extravascular lung water (EVLW). In this study, we compared a simpler approach using single arterial thermodilution derived measurements of ITBV and EVLW with the double-indicator dilution technique.
Prospective observational clinical study.
Surgical intensive care units of two university hospitals.
Global end-diastolic volume (GEDV) derived from single thermodilution was used for calculation of ITBV. Structural regression analysis of the first two thermo-dye dilution measurements in a derivation population of 57 critically ill patients (38 male, 19 female, 18-79 years, 56 +/- 15 years) revealed ITBV = (1.25 x GEDV)-28.4 (ml). This equation was then applied to all first measurements in a validation population of 209 critically ill patients (139 male, 70 female, 10-88 years, mean 53 +/- 19 years), and single-thermodilution ITBV (ITBV(ST)) and EVLW (EVLW(ST)) was calculated and compared to thermo-dye dilution derived values (ITBV(TD), EVLW(TD)). For inter-individual comparison, absolute values for ITBV and EVLW were normalised as indexed by body surface area (ITBVI) and body weight (EVLWI), respectively.
Linear regression analysis yielded a correlation of ITBVI(ST) = (1.05 x ITBVI(TD))-58.0 (ml/m2), r = 0.97, P < 0.0001. Bias between ITBVI(TD) and ITBVI(ST) was 7.6 (ml/m2) with a standard deviation of 57.4 (ml/m2). Single-thermodilution EVLWI (EVLWI(ST)) was calculated using ITBVI(ST) and revealed the correlation EVLWI(ST) = (0.83 x EVLWI(TD)) + 1.6 (ml/kg), r = 0.96, P < 0.0001. Bias between EVLWI(TD) and EVLWI(ST) was -0.2 (ml/kg) with a standard deviation of 1.4 (ml/kg). In detail, EVLWI(ST) systematically overestimated EVLWI(TD) at low-normal values for EVLWI and underestimated EVLWI at higher values (above 12 ml/kg).
Determinations of ITBV and EVLW by single thermodilution agreed closely with the corresponding values from the double-indicator technique. Since transpulmonary single thermodilution is simple to apply, less invasive and cheaper, all these features make it a promising technique for the bedside. Nevertheless, further validation studies are needed in the future.
经肺双指示剂稀释法是一种用于测量胸腔内血容量（ITBV）和血管外肺水（EVLW）的有用监测技术。在本研究中，我们将使用单动脉热稀释法测量ITBV和EVLW的更简单方法与双指示剂稀释技术进行了比较。
前瞻性观察性临床研究。
两家大学医院的外科重症监护病房。
将单热稀释法得出的全心舒张末期容积（GEDV）用于计算ITBV。对57例危重症患者（38例男性，19例女性，年龄18 - 79岁，平均56±15岁）的推导人群进行的前两次热染料稀释测量的结构回归分析显示，ITBV =（1.25×GEDV）- 28.4（ml）。然后将该公式应用于209例危重症患者（139例男性，70例女性，年龄10 - 88岁，平均53±19岁）的验证人群的所有首次测量中，计算单热稀释法的ITBV（ITBV(ST)）和EVLW（EVLW(ST)），并与热染料稀释法得出的值（ITBV(TD)，EVLW(TD)）进行比较。为了进行个体间比较，ITBV和EVLW的绝对值分别按体表面积（ITBVI）和体重（EVLWI）进行标准化。
线性回归分析得出ITBVI(ST) =（1.05×ITBVI(TD)）- 58.0（ml/m²），r = 0.97，P < 0.0001。ITBVI(TD)与ITBVI(ST)之间的偏差为7.6（ml/m²），标准差为57.4（ml/m²）。使用ITBVI(ST)计算单热稀释法的EVLWI（EVLWI(ST)），得出相关性EVLWI(ST) =（0.83×EVLWI(TD)）+ 1.6（ml/kg），r = 0.96，P < 0.0001。EVLWI(TD)与EVLWI(ST)之间的偏差为 - 0.2（ml/kg），标准差为1.4（ml/kg）。详细而言，在EVLWI处于低正常水平时，EVLWI(ST)系统性高估了EVLWI(TD)，而在较高水平（高于12 ml/kg）时则低估了EVLWI。
单热稀释法测定的ITBV和EVLW与双指示剂技术的相应值密切相符。由于经肺单热稀释法应用简单、侵入性较小且成本较低，所有这些特性使其成为一种有前景的床旁技术。然而，未来仍需要进一步的验证研究。
