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Very Low Tidal Volume Ventilation with Associated
Hypercapnia - Effects on Lung Injury in a Model for Acute
Respiratory Distress Syndrome
Hans Fuchs
1
*, Marc R. Mendler
1
, Dominik Scharnbeck
1
, Michael Ebsen
2
, Helmut D. Hummler
1
1 Division of Neonatology and Pediatric Critical Care, Department of Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany, 2 Medizinisches
Versorgungszentrum Sta¨dtisches Krankenhaus Kiel, Kiel, Germany
Abstract
Background: Ventilation using low tidal volumes with permission of hypercapnia is recommended to protect the lung in
acute respiratory distress syndrome. However, the most lung protective tidal volume in association with hypercapnia is
unknown. The aim of this study was to assess the effects of different tidal volumes with associated hypercapnia on lung
injury and gas exchange in a model for acute respiratory distress syndrome.
Methodology/Principal Findings: In this randomized controlled experiment sixty-four surfactant-depleted rabbits were
exposed to 6 hours of mechanical ventilation with the following targets: Group 1: tidal volume = 8–10 ml/kg/
PaCO 2 = 40 mm Hg; Group 2: tidal volume = 4–5 ml/kg/PaCO 2 = 80 mm Hg; Group 3: tidal volume = 3–4 ml/kg/
PaCO 2 = 120 mm Hg; Group 4: tidal volume = 2–3 ml/kg/PaCO 2 = 160 mm Hg. Decreased wet-dry weight ratios of the
lungs, lower histological lung injury scores and higher PaO 2 were found in all low tidal volume/hypercapnia groups (group
2, 3, 4) as compared to the group with conventional tidal volume/normocapnia (group 1). The reduction of the tidal volume
below 4–5 ml/kg did not enhance lung protection. However, oxygenation and lung protection were maintained at
extremely low tidal volumes in association with very severe hypercapnia and no adverse hemodynamic effects were
observed with this strategy.
Conclusion: Ventilation with low tidal volumes and associated hypercapnia was lung protective. A tidal volume below 4–
5 ml/kg/PaCO 2 80 mm Hg with concomitant more severe hypercapnic acidosis did not increase lung protection in this
surfactant deficiency model. However, even at extremely low tidal volumes in association with severe hypercapnia lung
protection and oxygenation were maintained.
背景:
低潮气量机械通气复合允许性高碳酸血症在急性呼吸窘迫综合症治疗中有肺保护作用。然而在允许性高碳酸血症下,最佳肺保护潮气量是不清楚的。本研究是在呼吸窘迫综合症模型中,允许性高碳酸血症下,不同潮气量对肺损伤和气体交换的影响。
方法学以及试验结果:
在随机选择64只表面活性物质耗尽的兔子行6小时机械通气,以下面分组:G1:TV = 8–10 ml/kg, PaCO 2 = 40 mmHg; G2: TV = 4–5 ml/kg ,PaCO 2 = 80mm Hg; G3: TV= 3–4 ml/kg, PaCO 2 = 120 mmHg; G4: TV = 2–3 ml/kg, PaCO 2 = 160 mmHg,去除肺干湿比重,降低组织学上肺损伤分值。较高的氧分压在所有低潮气量复合高碳酸血症组(2.3.4组与传统潮气量和正常碳酸血症患者)。潮气量减少到低于4-5ml/kg并没有增加肺保护作用。然后,氧化作用和肺保护仍然存在在极低潮气量以及严重的高碳酸血症是,没有观察到对血流动力学造成副作用。
结论:
低潮气量机械通气以及允许性高碳酸血症有肺保护作用。在肺表面活性物质缺乏的模型中,当潮气量低于4-5ml/Kg, PaCO 2 = 80 mm Hg伴随着呼吸性酸中毒,并不增加肺保护作用。然后,即便在极低的低潮气量复合高碳酸血症仍然有肺保护作用以及氧合作用。
文章见于:plos one 2011.08.6(8) 1-7 |
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