论文部分内容阅读
目的探讨肺泡复张后不同通气模式和自主呼吸在防止肺泡再萎陷中的作用。方法选择健康杂种犬18只,建立油酸所致急性呼吸窘迫综合征(ARDS)模型,行容积控制通气(VCV),呼气末正压(PEEP)16cm H_2O,潮气量(V_T)10ml/kg,通气频率30次/min,稳定后作为基础状态。以压力控制通气(PCV,PEEP 35cm H_2O,PCV 15cm H_2O,持续60s)行肺泡复张(RM),分为3组:VCV 组(VCV 通气,V_Υ 15ml/kg),PCV 组(PCV 通气,调节压力控制水平使 VT 保持在15ml/kg)和 SB 组(PCV 通气,保留一定程度的自主呼吸,调节压力控制水平使 V_Υ保持在15ml/kg)。3组通气频率(20次/min)、PEEP(10cm H_2O)和吸/呼比(1:2)均相同。观察4h 后处死动物。结果 VCV 组、PCV 组及 SB 组低位拐点分别为(16.1±1.9)cm H_2O,(17.4±1.5)cm H_2O 和(17.1±1.6)cm H_2O。在使用肺泡复张后,VCV 组 PaO_2维持在与基础状态相近的水平,而 PCV 组和 SB 组 PaO_2显著高于基础状态。与 VCV 组相比,SB 组 PaO_2在第30min 明显增高(P<0.05),肺内分流在第5、30与60min 有明显降低趋势(P 值分别为0.077、0.058、0.076)。(3)与基础状态相比,肺泡复张后各组平台压及平均气道压均明显降低,其中 SB 组平台压明显低于 VCV 组(P<0.05),平均气道压从第120min 直至实验结束均明显低于其他两组(P<0.05)。结论在肺泡复张后选用 PCV 并保留一定程度的自主呼吸,能弥补较低 PEEP 在防止肺泡再萎陷方面的不足,较 VCV 更有效、安全。
Objective To investigate the role of different ventilation patterns and spontaneous respiration in prevention of alveolar remodeling after alveolar recruitment. Methods A total of 18 healthy mongrel dogs were selected to establish acute respiratory distress syndrome (ARDS) model induced by oleic acid. The volume control ventilation (VCV), positive end expiratory pressure (PEEP) 16cm H 2 O and tidal volume (V_T) 10ml / kg , Ventilation frequency 30 times / min, as a basic state after stabilization. The rats were randomly divided into three groups: VCV group (VCV group, VY group: 15ml / kg), PCV group (group PCV group: PCV group, PCV group Pressure control levels maintained VT at 15 ml / kg) and SB group (ventilated at PCV, with some degree of spontaneous respiration, adjusting pressure control to maintain V_Y at 15 ml / kg). Ventilation frequency (20 beats / min), PEEP (10cm H_2O) and suction / exhalation ratio (1: 2) were the same in the three groups. After 4h, the animals were sacrificed. Results The inflection points of VCV group, PCV group and SB group were (16.1 ± 1.9) cm H 2 O, (17.4 ± 1.5) cm H 2 O and (17.1 ± 1.6) cm H 2 O, respectively. After alveolar remodeling, PaO 2 in VCV group was maintained at a level similar to basal state, while PaO 2 in PCV group and SB group was significantly higher than that in basal state. Compared with VCV group, PaO_2 in SB group was significantly increased at 30 min (P <0.05), and pulmonary shunt at 5, 30 and 60 min decreased significantly (P values were 0.077,0.058,0.076 respectively). (3) Compared with the basal state, the plateau pressure and mean airway pressure decreased significantly in all groups after alveolar seizure. The mean SBP was significantly lower in SB group than in VCV group (P <0.05) The end of the experiment were significantly lower than the other two groups (P <0.05). Conclusions PCV is selected after alveolar remodeling and a certain degree of spontaneous breathing is retained, which can make up for the lack of PEEP in resisting collapse of alveoli, which is more effective and safer than VCV.