Department of Anesthesiology and Operative Intensive Care Medicine (CCM/CVK), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.
EKU Elektronik GmbH, Leiningen, Germany.
J Clin Monit Comput. 2022 Jun;36(3):637-648. doi: 10.1007/s10877-021-00689-x. Epub 2021 Mar 18.
Admixture of nitric oxide (NO) to the gas inspired with mechanical ventilation can be achieved through continuous, timed, or pulsed injection of NO into the inspiratory limb. The dose and timing of NO injection govern the inspired and intrapulmonary effect site concentrations achieved with different administration modes. Here we test the effectiveness and target reliability of a new mode injecting pulsed NO boluses exclusively during early inspiration.
An in vitro lung model was operated under various ventilator settings. Admixture of NO through injection into the inspiratory limb was timed either (i) selectively during early inspiration ("pulsed delivery"), or as customary, (ii) during inspiratory time or (iii) the entire respiratory cycle. Set NO target concentrations of 5-40 parts per million (ppm) were tested for agreement with the yield NO concentrations measured at various sites in the inspiratory limb, to assess the effectiveness of these NO administration modes.
Pulsed delivery produced inspiratory NO concentrations comparable with those of customary modes of NO administration. At low (450 ml) and ultra-low (230 ml) tidal volumes, pulsed delivery yielded better agreement of the set target (up to 40 ppm) and inspiratory NO concentrations as compared to customary modes. Pulsed delivery with NO injection close to the artificial lung yielded higher intrapulmonary NO concentrations than with NO injection close to the ventilator. The maximum inspiratory NO concentration observed in the trachea (68 ± 30 ppm) occurred with pulsed delivery at a set target of 40 ppm.
Pulsed early inspiratory phase NO injection is as effective as continuous or non-selective admixture of NO to inspired gas and may confer improved target reliability, especially at low, lung protective tidal volumes.
通过将一氧化氮（NO）连续、定时或脉冲注入吸气支，可将其混入机械通气时吸入的气体中。NO 注射的剂量和时间决定了不同给药方式下达到的吸入和肺内作用部位浓度。在此，我们测试了一种新的给药模式的有效性和靶位可靠性，该模式仅在吸气早期脉冲注射 NO 弹丸。
在各种呼吸机设置下，对体外肺模型进行操作。NO 的混合通过将其注入吸气支来实现，要么（i）在吸气早期选择性地（“脉冲输送”），要么像常规那样，（ii）在吸气时间内或（iii）在整个呼吸周期内进行。测试了设定的 NO 目标浓度为 5-40ppm，以评估这些 NO 给药方式的有效性，即与吸气支中各个部位测量的产生的 NO 浓度相吻合的程度。
与常规的 NO 给药方式相比，脉冲输送可产生相似的吸气期 NO 浓度。在低（450ml）和超低（230ml）潮气量下，与常规模式相比，脉冲输送能更好地达到设定的目标（最高 40ppm）和吸气期 NO 浓度。在靠近人工肺进行的脉冲输送时，NO 注射可产生更高的肺内 NO 浓度，而在靠近呼吸机进行的脉冲输送时则较低。在设定目标为 40ppm 时，气管内观察到的最大吸气期 NO 浓度（68±30ppm）出现在脉冲输送时。
与连续或非选择性将 NO 混合到吸入气中相比，脉冲早期吸气相 NO 注射同样有效，并且可能改善靶位可靠性，尤其是在低、肺保护性潮气量时。
