Objective To investigate the effects of extrinsic positive end-expiratory pressure (PEEPe) on work of breathing in patients with chronic obstructive pulmonary disease (COPD) and their corresponding mechanism.Methods...Objective To investigate the effects of extrinsic positive end-expiratory pressure (PEEPe) on work of breathing in patients with chronic obstructive pulmonary disease (COPD) and their corresponding mechanism.Methods Ten ventilated patients with COPD were included in the study. A Bicore CP-100 pulmonary monitor (Bicore Monitoring System, USA) was used for monitoring respiratory mechanics. First, dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) was measured when PEEPe was zero, which was called PEEPi,dynz. Then the PEEPe was set randomly at 0%, 40%, 60%, 80% and 100% of PEEPi,dynz respectively. Pulmonary mechanics and other parameters (heart rate, blood pressure and blood gas analysis) were measured 30 minutes after the level of PEEPe was changed.Results Work of breathing patient (WOBp), pressure time product, difference of esophageal pressure and PEEPi,dyn decreased significantly when PEEPe was applied, and continued decreasing as PEEPe was increased. Work of breathing ventilator increased significantly when PEEPe was increased to 80% and 100% of PEEPi,dynz. Significantly positive linear correlation was found between the changes in WOBp and in PEEPi,dyn.Conclusions WOBp decreases gradually as PEEPe is increased. WOBp decreases by narrowing the difference between the alveolus pressure and the central airway pressure at the end of expiration when PEEPe is applied.展开更多
本文采用数字式粘度仪对不同温度和促进剂含量下添加氢氧化铝(ATH)的不饱和聚酯树脂(UPR)的粘度进行测试,然后以获取的实验数据作为参数,对复合材料部件模型用RTM(Resin transfer molding)和VARTM(Vacuum assisted resin transfer moldi...本文采用数字式粘度仪对不同温度和促进剂含量下添加氢氧化铝(ATH)的不饱和聚酯树脂(UPR)的粘度进行测试,然后以获取的实验数据作为参数,对复合材料部件模型用RTM(Resin transfer molding)和VARTM(Vacuum assisted resin transfer molding)两种工艺进行模拟仿真。仿真结果表明,在相同的参数条件和灌注方案下,VARTM工艺的填充时间小于等于RTM工艺的填充时间。当注口大于出口时,VARTM和RTM的填充时间基本相同;当注口小于出口时,VARTM工艺的填充时间要少于RTM工艺的填充时间。展开更多
文摘Objective To investigate the effects of extrinsic positive end-expiratory pressure (PEEPe) on work of breathing in patients with chronic obstructive pulmonary disease (COPD) and their corresponding mechanism.Methods Ten ventilated patients with COPD were included in the study. A Bicore CP-100 pulmonary monitor (Bicore Monitoring System, USA) was used for monitoring respiratory mechanics. First, dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) was measured when PEEPe was zero, which was called PEEPi,dynz. Then the PEEPe was set randomly at 0%, 40%, 60%, 80% and 100% of PEEPi,dynz respectively. Pulmonary mechanics and other parameters (heart rate, blood pressure and blood gas analysis) were measured 30 minutes after the level of PEEPe was changed.Results Work of breathing patient (WOBp), pressure time product, difference of esophageal pressure and PEEPi,dyn decreased significantly when PEEPe was applied, and continued decreasing as PEEPe was increased. Work of breathing ventilator increased significantly when PEEPe was increased to 80% and 100% of PEEPi,dynz. Significantly positive linear correlation was found between the changes in WOBp and in PEEPi,dyn.Conclusions WOBp decreases gradually as PEEPe is increased. WOBp decreases by narrowing the difference between the alveolus pressure and the central airway pressure at the end of expiration when PEEPe is applied.
文摘本文采用数字式粘度仪对不同温度和促进剂含量下添加氢氧化铝(ATH)的不饱和聚酯树脂(UPR)的粘度进行测试,然后以获取的实验数据作为参数,对复合材料部件模型用RTM(Resin transfer molding)和VARTM(Vacuum assisted resin transfer molding)两种工艺进行模拟仿真。仿真结果表明,在相同的参数条件和灌注方案下,VARTM工艺的填充时间小于等于RTM工艺的填充时间。当注口大于出口时,VARTM和RTM的填充时间基本相同;当注口小于出口时,VARTM工艺的填充时间要少于RTM工艺的填充时间。
