浮动胸壁对犬心肺功能的损害及机械通气和肋骨牵引的治疗效果

目的 观察浮动胸壁对心肺功能的影响以及机械通气和肋骨牵引的疗效。方法 杂种1犬16只建立小面积（10cm^2/kg）和大面积（20cm^2/kg）浮动胸壁动物模型，每组8只，用胸腔置管、Swan-Ganz导管、血气分析等观察心排量（CO）、中心静脉压（CVP）、平均动脉压（MAP）、肺动脉压（PAP）、动脉氧分压（PaO2），肺动脉静脉分流分数（Qs.／Qt）及胸膜腔内压等的变化和机械通气、肋骨牵引固定的治疗效果。结果 浮动胸壁模型完成后，均出现反常呼吸，胸腔内压力为负值，未出现软化部分膨出；小面积组动脉血氧饱和度（SaO2）下降（P＜0．05），Qs/Qt下降（P＜0．05）。与治疗前比较，机械通气治疗后小面积组Qs/Qt下降（P＜0．05），CO和SaO2则升高（P＜0．05）；而大面积组SaO2、PaO2明显升同（P＜0．01），Qs/Qt和PaCO2下降（P＜0．05）。结论 浮动胸壁的病理胸腔容积减少为基础，机械通气和肋骨牵引固定是有效的治疗手段，机械通气对大面积浮动胸壁呼吸功能障碍的疗效更好。

Influence of floating thoracic wall and curative effect of mechanical ventilation and rib traction on cardiopulmonary function

Objective To study the influence of floating thoracic wall and the curative effect of mechanical ventilation and rib traction on cardiopulmonary function. Methods Floating thoracic wall models of small areas(10 cm 2/kg, Group A) and large areas(20 cm 2/kg, Group B) were established in hybrid dogs. The cardiac output (CO), central venous pressure (CVP), mean arterial pressure (MAP), pulmonary arterial pressure (PAP), partial pressure of oxygen inartery (PaO 2), arterial oxygen saturation (SaO 2), intrapulmonary shunt fraction (Qs/Qt) and intrapleural pressure were measured with Swan Ganz catheters, blood gas analysis and intrathoracic cannula. And the curative effect of mechanical ventilation and rib traction on cardiopulmonary function was studied, too. Results Paradoxical respiration occurred and the intrathoracic pressure kept negative but with no bulge of malactic tissues after the fulfilment of the floating thoracic wall models. SaO 2 decreased( P < 0.05 ), but CVP increased in Group A ( P <0.05). CO, PaO 2 and SaO 2 decreased significantly( P < 0.01 ), but Qs/Qt increased significantly in Group B ( P <0.01). After treatment of rib traction, SaO 2 increased( P < 0.05 ), but Qs/Qt decreased in Group A ( P <0.05). CO, PaO 2 and SaO 2 increased significantly( P < 0.01 ), but Qs/Qt decreased in Group B ( P <0.05). After treatment of mechanical ventilation, Qs/Qt decreased( P < 0.05 ),but CO and SaO 2 increased in Group A ( P <0.05). SaO 2 and PaO 2 increased obviously( P < 0.01 ),Qs/Qt and partial pressure of carbon dioxide in artery (PaCO 2) decreased obviously in Group B ( P <0.05). Conclusions The decrease of thoracic capacity is the main reason of the worseness of cardiopulmonary function after the establishment of floating thoracic wall. Mechanical ventilation and rib traction are effective ways for improvement of cardiopulmonary function, and mechanical ventilation has better effect on respiratory function disturbance in floating thoracic wall models of large areas.