Duenges Bastian, Vogt Andreas, Bodenstein Marc, Wang Hemei, Böhme Stefan, Röhrig Bernd, Baumgardner James E, Markstaller Klaus
Department of Anesthesiology, Johannes Gutenberg- University, Mainz, Germany.
Anesth Analg. 2009 Dec;109(6):1831-5. doi: 10.1213/ANE.0b013e3181bbc401.
The multiple inert gas elimination technique was developed to measure shunt and the ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung (V(A)'/Q') distributions. Micropore membrane inlet mass spectrometry (MMIMS), instead of gas chromatography, has been introduced for inert gas measurement and shunt determination in a rabbit lung model. However, agreement with a frequently used and accepted method for quantifying deficits in arterial oxygenation has not been established. We compared MMIMS-derived shunt (M-S) as a fraction of total cardiac output (CO) with Riley shunt (R-S) derived from the R-S formula in a porcine lung injury model.
To allow a broad variance of atelectasis and therefore shunt fraction, 8 sham animals did not receive lavage, and 8 animals were treated by lung lavages with 30 mL/kg warmed lactated Ringer's solution as follows: 2 animals were lavaged once, 5 animals twice, and 1 animal 3 times. Variables were recorded at baseline and twice after induction of lung injury (T1 and T2). Retention data of sulfur hexafluoride, krypton, desflurane, enflurane, diethyl ether, and acetone were analyzed by MMIMS, and M-S was derived using a known algorithm for the multiple inert gas elimination technique. Standard formulas were used for the calculation of R-S.
Forty-four pairs of M-S and R-S were recorded. M-S ranged from 0.1% to 35.4% and R-S from 3.7% to 62.1%. M-S showed a correlation with R-S described by linear regression: M-S = -4.26 + 0.59 x R-S (r(2) = 0.83). M-S was on average lower than R-S (mean = -15.0% CO, sd = 6.5% CO, and median = -15.1), with lower and upper limits of agreement of -28.0% and -2.0%, respectively. The lower and upper limits of the 95% confidence intervals were -17.0 and -13.1 (P < 0.001, Student's t-test).
Shunt derived from MMIMS inert gas retention data correlated well with R-S during breathing of oxygen. Shunt as derived by MMIMS was generally less than R-S.
多种惰性气体消除技术被开发用于测量分流以及肺任何部位的肺泡通气与同时的肺泡毛细血管血流比值（V(A)'/Q'）分布。在兔肺模型中，已引入微孔膜进样质谱法（MMIMS）而非气相色谱法来进行惰性气体测量和分流测定。然而，与一种常用且被认可的量化动脉氧合缺陷的方法之间的一致性尚未确立。我们在猪肺损伤模型中，将MMIMS得出的作为心输出量（CO）一部分的分流（M-S）与根据R-S公式得出的莱利分流（R-S）进行了比较。
为使肺不张及因此的分流分数有广泛差异，8只假手术动物未接受灌洗，8只动物用30 mL/kg温热乳酸林格液进行肺灌洗，如下：2只动物灌洗1次，5只动物灌洗2次，1只动物灌洗3次。在基线以及诱导肺损伤后两次（T1和T2）记录变量。通过MMIMS分析六氟化硫、氪、地氟烷、恩氟烷、乙醚和丙酮的潴留数据，并使用多种惰性气体消除技术的已知算法得出M-S。使用标准公式计算R-S。
记录了44对M-S和R-S。M-S范围为0.1%至35.4%，R-S范围为3.7%至62.1%。M-S与通过线性回归描述的R-S存在相关性：M-S = -4.26 + 0.59×R-S（r(2)=0.83）。M-S平均低于R-S（均值=-15.0%CO，标准差=6.5%CO，中位数=-15.1），一致性下限和上限分别为-28.0%和-2.0%。95%置信区间的下限和上限分别为-17.0和-13.1（P<0.001，学生t检验）。
在吸氧过程中，由MMIMS惰性气体潴留数据得出的分流与R-S相关性良好。MMIMS得出的分流通常小于R-S。
