胸部枪伤瞬时及早期心血管效应的实验研究

Experimental study on instantaneous and early cardiovascular effects of thoracic bullet wound

目的 探讨胸部枪伤瞬时及早期心血管效应及其机制。 方法 30只家兔随机平均分为A :胸部贯穿伤组 (模型组 )、B :预扎肋间动脉致伤组、C :人工气胸后致伤组、D :预扎肋间动脉 +人工气胸后致伤组、E :胸壁切线伤组。分别用 5 .5 6mm小口径步枪致伤 ,连续监测动脉压、心率、静脉压、心电图、左室内压等。 结果 A组伤前血压峰值为 ( 14.80± 1.2 9)kPa ( 1kPa =7.5mmHg) ,枪伤瞬间血压即刻呈单波峰升高 ,达伤前的 ( 1.5 8± 0 .0 8)倍 ,而后迅速降低至伤前水平以下 ,10s下降到最低点 ,30s开始回升 ,1min后回升至伤前的 ( 0 .80± 0 .0 7)倍 ,并逐渐稳定。静脉压瞬时升高后随即下降 ,左室内压和心率出现瞬时下降、而后逐渐恢复 ,B组和C组变化幅度较小。D组和E组仅枪击瞬间有短暂变化。 结论 胸部枪伤瞬间动、静脉压升高 ,而左室内压无变化 ,为枪弹冲击波直接引起。伤后数秒内血压下降 ,心动过缓 ,心肌受抑制和左室内压下降 ,而中心静脉压尚正常 ,提示与迷走反射有关。模型组于伤后 2h血压再度下降 ,则可能与胸内失血和肺损伤有关 ,缺氧也造成了心肌收缩力下降。预扎肋间动脉及临时造成人工气胸防止肺实质损伤 ,可减轻枪伤早期的心血管功能障碍。

Objective To explore the instantaneous and early cardiovascular effects and mechanism of thoracic bullet wound. Methods A total of 30 rabbits were divided randomly and equally into 5 groups: penetrating thoracic wound group(Group A, also the model group), ligation of intercostal artery group (Group B), artificial pneumothorax group(Group C), ligation of intercostal artery with artificial pneumothorax group(Group D) and tangential wound of thoracic wall group (Group E). Then, they were injured with a small-bored rifle. Arterial and venous pressure, left ventricular pressure, heart rates and electrocardiogram were observed continuously after injury. Results In Group A, the arterial pressure rose up to 11.85 mm Hg (1 mm Hg = 0.133 kPa) shortly after injury, then, declined to 3.38 mm Hg and returned to 6.00 mm Hg after 1 minute and became steady gradually at last. The venous pressure rose instantly, then declined. The left ventricular pressure and heart rates declined instantly, then resumed gradually. These parameters in Group B and Group C changed little. In Group D and Group E, the changes remained just for a short moment. Conclusions Shortly after injury, the arterial and the venous pressure is increased with no change of the left ventricular pressure which is aroused directly by the bullet blast wave obviously. In a few seconds after injury, the decrease of the blood pressure, the left ventricular bradycardia pressure and normal central venous pressure are related with the vagus reflects. In Group A, the blood pressure declining 2 hours after injury are probably ascribed to thoracic cavity hemorrhage and lung trauma. Anoxygen also can weaken the myocardial contract capability. The ligation of the intercostal artery and the temporary artificial pneumothorax to prevent the pulmonary injury can reduce cardiovascular dysfunction in the early period of the wound.