Chinese Journal of Emergency Medicine 2011;20(2):137-142
doi:10.3760/cma.j.issn.1671-0282.2011.02.007
Protective effects of pulmonary stretch reflex on the lung injury in rabbits with acute respiratory distress syndrome
Xiaoyan WU ; Yingzi HUANG ; Yi YANG ; Huogen LIU ; Dongya HUANG ; Rui TANG ; Haibo QIU
Keywords
Pulmonary stretch reflex; Vagus nerve; Lung injury; Acute respiratory distress syndrome; Electrical activity of diaphragm; Pulmonary mechanics; Inflammation; Mechanical ventilation
Country
China
Language
Chinese
Abstract
Objective To evaluate the effect of the pulmonary stretch reflex on the lung injury in acute respiratory distress syndrome (ARDS). Method ARDS models of rabbits were induced by intratracheal infusion hydrochloric acid and ventilated with neurally adjusted ventilatory assist (NAVA) with a tidal volume ( VT) of 6 mL/kg and the electrical activity of diaphragm ( Eadi)-determined PEEP level. The rabbits were randomly ( random number) divided into two groups: ( 1 ) sham operation (Sham) group ( n = 5 ),(2) bilateral vagotom (VAG) group( n = 5 ). Gas exchange and pulmonary mechanics were determined at baseline, after lung injury and ventilation 1, 2, 3 h respectively. Indices about pulmonary permeability,pathological changes and inflammatory response were also measured. Results Compared with Sham group,the PaO2/FiO2in VAG group decreased significantly at ventilation 2 h, 3 h (P <0.05). There was no significant difference on PaCO2 between Sham and VAG group (P > 0.05 ), and VAG group had the higher VT,peak pressure ( Ppeak), mean pressure (Pm) compared with Sham group at the time point of ventilation 1 h, 2 h, 3 h (P<0.05). Compared with Sham group, the dead space fraction (VD/VT) and the respiratory system elastance (Ers) in VAG group increased (P < 0.05 ) and the static pulmonary compliance (Cst)decreased markedly (P < 0.05 ) after 3 h ventilation. The wet/dry weight (W/D), lung injury score, tumor necrosis factor-α ( TNF-α), interleukin-8 ( IL-8 ), myeloperoxidase ( M PO ) and malondialdehyde ( M DA )in VAG group elevated significantly when compared with Sham group ( P < 0.05 ). Conclusions The lung injury in ARDS was aggravated after bilateral vagotomy, which demonstrated that the pulmonary stretch reflex may have the lung protective effect.
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