ASV® 和用于治疗 ARDS 病人的肺保护通气

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日期: 12.09.2022

美国最近一项研究发现，ASV 的目标设置与用于治疗 ARDS 病人的肺保护通气策略一致。

研究者在 17 名大多被动型中度到严重 ARDS 病人中开展随机交叉试验，以比较适应性支持通气 (ASV) 模式的自动设置与医院的护理标准模式适应性压力通气 (APV) (Baedorf Kassis EN, Bastos AB, Schaefer MS, et al. Adaptive Support Ventilation and Lung-Protective Ventilation in ARDS [published online ahead of print, 2022 Aug 16]. Respir Care.2022;respcare.10159. doi:10.4187/respcare.101591)。在 ASV 模式下，呼吸频率和潮气量自动调整，以维持所设置的分钟通气量，同时根据医院的护理标准在 APV 模式下将潮气量 (VT) 设为 6 mL/kg IBW。病人在每个模式下通气 1–2 小时，维持一致的分钟通气量。

主要结果是经理想体重校正后的潮气量 (VT)。总体上，在 ASV 下 VT 自动调整产生的 VT 稍高 (6.29 [5.87–6.99] mL/kg IBW vs 6.04 [6.01–6.06] mL/kg IBW, P =0.035)。作者说明，虽然在统计学上很显著，但绝对而言此差异太小，在临床上不相关。重要的是 VT 始终在 8 mL/kg 以下，因此在一般接受的肺保护范围以内。此外，ASV 下部分病人的 VT 较低，且顺应性低、呼气时间常数短，表明根据病人的呼吸力学指标进行个体滴定。

在次要结果方面，ASV 下的呼吸频率略低，然而两模式下的平台压、驱动压和机械功率相似。但在顺应性较低的病人中 ASV 下的机械功率更低，尤其是 VT 也降低的病人。

结果显示，ASV 下的设置与肺保护策略一致。此外，ASV 根据病人的呼吸力学指标调整 VT，在肺部较僵硬受试者中输送更低的 VT 和机械功率。

脚注

参考文献

1. Baedorf Kassis EN, Bastos AB, Schaefer MS, et al. Adaptive Support Ventilation and Lung-Protective Ventilation in ARDS [published online ahead of print, 2022 Aug 16]. Respir Care. 2022;respcare.10159. doi:10.4187/respcare.10159

Adaptive Support Ventilation and Lung-Protective Ventilation in ARDS.

Baedorf Kassis EN, Bastos AB, Schaefer MS, et al. Adaptive Support Ventilation and Lung-Protective Ventilation in ARDS [published online ahead of print, 2022 Aug 16]. Respir Care. 2022;respcare.10159. doi:10.4187/respcare.10159

BACKGROUND

Adaptive support ventilation (ASV) is a partially closed-loop ventilation mode that adjusts tidal volume (VT) and breathing frequency (f) to minimize mechanical work and driving pressure. ASV is routinely used but has not been widely studied in ARDS.

METHODS

The study was a crossover study with randomization to intervention comparing a pressure-regulated, volume-targeted ventilation mode (adaptive pressure ventilation [APV], standard of care at Beth Israel Deaconess Medical Center) set to VT 6 mL/kg in comparison with ASV mode where VT adjustment is automated. Subjects received standard of care (APV) or ASV and then crossed over to the alternate mode, maintaining consistent minute ventilation with 1-2 h in each mode. The primary outcome was VT corrected for ideal body weight (IBW) before and after crossover. Secondary outcomes included driving pressure, mechanics, gas exchange, mechanical power, and other parameters measured after crossover and longitudinally.

RESULTS

Twenty subjects with ARDS were consented, with 17 randomized and completing the study (median PaO2 /FIO2 146.6 [128.3-204.8] mm Hg) and were mostly passive without spontaneous breathing. ASV mode produced marginally larger VT corrected for IBW (6.3 [5.9-7.0] mL/kg IBW vs 6.04 [6.0-6.1] mL/kg IBW, P = .035). Frequency was lower with patients in ASV mode (25 [22-26] breaths/min vs 27 [22-30)] breaths/min, P = .01). In ASV, lower respiratory-system compliance correlated with smaller delivered VT/IBW (R2 = 0.4936, P = .002). Plateau (24.7 [22.6-27.6] cm H2O vs 25.3 [23.5-26.8] cm H2O, P = .14) and driving pressures (12.8 [9.0-15.8] cm H2O vs 11.7 [10.7-15.1] cm H2O, P = .29) were comparable between conventional ventilation and ASV. No adverse events were noted in either ASV or conventional group related to mode of ventilation.

CONCLUSIONS

ASV targeted similar settings as standard of care consistent with lung-protective ventilation strategies in mostly passive subjects with ARDS. ASV delivered VT based upon respiratory mechanics, with lower VT and mechanical power in subjects with stiffer lungs.