肺局部低温小潮气量通气对急性呼吸窘迫综合征犬动脉血气分析的影响

Effect of Lung Local Hypothermia with Low Tidal Volume Ventilation on Arterial Blood Gas of Dogs with Acute Respiratory Distress Syndrome

目的研究肺局部低温小潮气量通气对急性呼吸窘迫综合征(ARDS)犬动脉血气分析的影响。方法将健康雄性杂种犬24只,用股静脉注射油酸的方法制备成ARDS模型后,随机分为4组,每组6只,即低温小潮气量机械通气组(HL组)、室温小潮气量机械通气组(RL组)、低温常规机械通气组(HC组)、室温常规机械通气组(RC组)。气管插管后进行机械通气,低温组和常温组分别通-2～0℃低温气体和25℃室温气体;小潮气量组和常规机械通气组呼吸参数分别设为:VT6mL/kg,RR20次/min,I/E=1:2和VT12mL/kg,RR20次/min,I/E=1:2。观察注射油酸前,达到ARDS时,ARDS后1、2、3h各时间点的血气指标(PaO2、PaCO2、HCO3-、pH)变化。结果各组在ARDS时,ARDS后PaO2较基础值比较均显著下降(均P<0.05),HL组PaO2在ARDS后3h时和RL、HC、RC组比较差异均有统计学意义(均P<0.05);各组在ARDS后PaCO2较基础值比较均有所升高,其中HL组PaCO2、pH值在ARDS后和HC组比较差异有统计学意义(P<0.05),但和RC组比较无统计学意义(P>0.05);各组HCO3-在ARDS后均有所下降,但HL组在ARDS后3h和RC组比较差异有统计学意义(P<0.05)。结论肺局部低温小潮气通气一方面可以改善氧合,提高氧分压;另一方面,与室温小潮气量相比,其对PaCO2、HCO3-、pH值影响小。

Objective To study the effect of lung local hypothermia with low tidal volume mechanical ventilation on arterial blood gas in acute respiratory distress syndrome（ARDS）dogs.Methods The dog model of ARDS was established by femoral vein injection of oleic acid in tewnty-four healthy male dogs.The model dogs were randomly divided into four groups：low tidal volume mechanical ventilation with cold air group（HL group）,low tidal volume ventilation with room air group（RL group）,traditional tidal volume ventilation with cold air group（HC group） and traditional tidal volume ventilation with room air （RC group）,with 6 dogs in each group.The animals were endotracheally intubated and then mechanically ventilated with cold air （-2 ～0 ℃） and room air （25 ℃）.The low tidal volume and traditional volume ventilation parameters were set to VT 6 mL/kg,RR 20/min,I/E=1∶2 and VT 12 mL/kg,RR 20/min,I/E=1∶2,respectively.The changes of blood gas parameters（PaO2、PaCO2、HCO3-、pH） were observed before oleic acid injection,at the time of ARDS and at 1,2,3 h after ARDS.Results Compared with the basic values,PaO2 in every group significantly decreased at the time of ARDS and after ARDS（all P0.05）,PaO2 in HL group was significantly higher than that in the other groups at 3 h after ARDS （all P0.05）.PaCO2 in every group significantly increased after ARDS,PaCO2 and pH in HL group were lower than those in HC group after ARDS（P0.05）,but there was no significant difference in PaCO2 and pH between HL group and RC group（P0.05）.HCO3-in every group significantly decreased after ARDS,and HCO3-in HL group was higher than that in RC group at 3 h after ARDS（P0.05）.Conclusion Lung low tidal vloume mechanical ventilation with local hypothermia could improve the oxygenation and increase the partial pressure of oxygen.Compared with low tidal volume ventilation with room air,low tidal vloume ventilation with cold air had less influence on the PaCO2,HCO3-and pH.