Background Although severe encephalopathy has been proposed as a possible contraindication to the use of noninvasive positive-pressure ventilation （NPPV）, increasing clinical reports showed it was effective in patie...Background Although severe encephalopathy has been proposed as a possible contraindication to the use of noninvasive positive-pressure ventilation （NPPV）, increasing clinical reports showed it was effective in patients with impaired consciousness and even coma secondary to acute respiratory failure, especially hypercapnic acute respiratory failure （HARF）. To further evaluate the effectiveness and safety of NPPV for severe hypercapnic encephalopathy, a prospective case-control study was conducted at a university respiratory intensive care unit （RICU） in patients with acute exacerbation of chronic obstructive pulmonary disease （AECOPD） during the past 3 years. Methods Forty-three of 68 consecutive AECOPD patients requiring ventilatory support for HARF were divided into 2 groups, which were carefully matched for age, sex, COPD course, tobacco use and previous hospitalization history, according to the severity of encephalopathy, 22 patients with Glasgow coma scale （GCS） 〈10 served as group A and 21 with GCS 〉10 as group B. Results Compared with group B, group A had a higher level of baseline arterial partial CO2 pressure （（102±27） mmHg vs （74±17） mmHg, P〈0.01）, lower levels of GCS （7.5±1.9 vs 12.2±1.8, P〈0.01）, arterial pH value （7.18±0.06 vs 7.28±0.07, P〈0.01） and partial 02 pressure/fraction of inspired 02 ratio （168±39 vs 189±33, P〈0.05）. The NPPV success rate and hospital mortality were 73% （16/22） and 14% （3/22） respectively in group A, which were comparable to those in group B （68% （15/21） and 14% （3/21） respectively, all P〉0.05）, but group A needed an average of 7 cmH20 higher of maximal pressure support during NPPV, and 4, 4 and 7 days longer of NPPV time, RICU stay and hospital stay respectively than group B （P〈0.05 or P〈0.01）. NPPV therapy failed in 12 patients （6 in each group） because of excessive airway secretions （7 patients）, hemodynamic instability （2）, worsening of dyspnea and deterioration of gas exchange （2）, and gastric content aspiration （1）. Conclusions Selected patients with severe hypercapnic encephalopathy secondary to HARF can be treated as effectively and safely with NPPV as awake patients with HARF due to AECOPD; a trial of NPPV should be instituted to reduce the need of endotracheal intubation in patients with severe hypercapnic encephalopathy who are otherwise good candidates for NPPV due to AECOPD.展开更多
目的比较压力控制通气(PCV)与压力支持通气(PSV)对慢性阻塞性肺疾病(COPD)呼吸衰竭患者的通气参数的影响.方法 COPD所致呼吸衰竭患者35例,在给予常规内科治疗的同时,使用口鼻面罩分别接受持续气道正压(CPAP)、PSV和PCV模式通气各60 min....目的比较压力控制通气(PCV)与压力支持通气(PSV)对慢性阻塞性肺疾病(COPD)呼吸衰竭患者的通气参数的影响.方法 COPD所致呼吸衰竭患者35例,在给予常规内科治疗的同时,使用口鼻面罩分别接受持续气道正压(CPAP)、PSV和PCV模式通气各60 min.PCV时采用辅助/控制(A/C)模式,监测患者的吸气流速和气道压力变化,以调整预置吸气时间(TI),通气频率(f)为6次/min,吸气压力(Pinsp)为12～20 cm H2O,呼气末气道正压(PEEP)为4 cm H2O,吸气触发灵敏度(trigger)为2 L/min,偏流(bias flow)为20 L/min,吸入氧浓度(FiO2)为0.4～0.5;PSV时的压力支持水平(PS)为8～16 cm H2O(即Pinsp-PEEP),最大吸气时间限制(Timax)为3 s,其余参数保持不变.监测潮气量(VT)、TI、每分通气量(MV)、吸气/呼吸周期时间比(TI/Ttot)和呼吸频率(RR),计算浅快呼吸指数(RSBI),并采集动脉血作血气分析.结果患者在接受PSV和PCV通气时的VT均明显高于CPAP时,RR逐渐减慢(P＜0.05);PCV时的MV明显低于PSV与CPAP时.PCV时的TI较PSV和CPAP时明显延长[(1.23±0.09)s与(1.06±0.11)s、(0.89±0.10)s,P＜0.05],PCV与PSV时的TI/Ttot较CPAP时减小;浅快呼吸指数(RSBI)从CPAP时的(78.2±4.9)breaths·min-1·L-1降至PSV时的(44.9±2.6)breaths·min-1·L-1和PCV时的(35.6±1.9)breaths·min-1·L-1(P＜0.05).PSV和PCV模式时的PaO2/FiO2明显高于CPAP时(264.5±72.3、273.1±71.2与221±56.4,P＜0.05),三种模式下的PaCO2均无显著性差异.结论与PSV相比,应用PCV治疗呼吸衰竭时通过预置适宜的TI及备用通气频率,能在与PSV相同的气道压的前提下提供相近的VT及MV;PCV不仅有助于调控患者的呼吸频率,提供必要的通气支持,还有利于减轻患者呼吸肌的作功.展开更多
文摘Background Although severe encephalopathy has been proposed as a possible contraindication to the use of noninvasive positive-pressure ventilation （NPPV）, increasing clinical reports showed it was effective in patients with impaired consciousness and even coma secondary to acute respiratory failure, especially hypercapnic acute respiratory failure （HARF）. To further evaluate the effectiveness and safety of NPPV for severe hypercapnic encephalopathy, a prospective case-control study was conducted at a university respiratory intensive care unit （RICU） in patients with acute exacerbation of chronic obstructive pulmonary disease （AECOPD） during the past 3 years. Methods Forty-three of 68 consecutive AECOPD patients requiring ventilatory support for HARF were divided into 2 groups, which were carefully matched for age, sex, COPD course, tobacco use and previous hospitalization history, according to the severity of encephalopathy, 22 patients with Glasgow coma scale （GCS） 〈10 served as group A and 21 with GCS 〉10 as group B. Results Compared with group B, group A had a higher level of baseline arterial partial CO2 pressure （（102±27） mmHg vs （74±17） mmHg, P〈0.01）, lower levels of GCS （7.5±1.9 vs 12.2±1.8, P〈0.01）, arterial pH value （7.18±0.06 vs 7.28±0.07, P〈0.01） and partial 02 pressure/fraction of inspired 02 ratio （168±39 vs 189±33, P〈0.05）. The NPPV success rate and hospital mortality were 73% （16/22） and 14% （3/22） respectively in group A, which were comparable to those in group B （68% （15/21） and 14% （3/21） respectively, all P〉0.05）, but group A needed an average of 7 cmH20 higher of maximal pressure support during NPPV, and 4, 4 and 7 days longer of NPPV time, RICU stay and hospital stay respectively than group B （P〈0.05 or P〈0.01）. NPPV therapy failed in 12 patients （6 in each group） because of excessive airway secretions （7 patients）, hemodynamic instability （2）, worsening of dyspnea and deterioration of gas exchange （2）, and gastric content aspiration （1）. Conclusions Selected patients with severe hypercapnic encephalopathy secondary to HARF can be treated as effectively and safely with NPPV as awake patients with HARF due to AECOPD; a trial of NPPV should be instituted to reduce the need of endotracheal intubation in patients with severe hypercapnic encephalopathy who are otherwise good candidates for NPPV due to AECOPD.
文摘目的比较压力控制通气(PCV)与压力支持通气(PSV)对慢性阻塞性肺疾病(COPD)呼吸衰竭患者的通气参数的影响.方法 COPD所致呼吸衰竭患者35例,在给予常规内科治疗的同时,使用口鼻面罩分别接受持续气道正压(CPAP)、PSV和PCV模式通气各60 min.PCV时采用辅助/控制(A/C)模式,监测患者的吸气流速和气道压力变化,以调整预置吸气时间(TI),通气频率(f)为6次/min,吸气压力(Pinsp)为12～20 cm H2O,呼气末气道正压(PEEP)为4 cm H2O,吸气触发灵敏度(trigger)为2 L/min,偏流(bias flow)为20 L/min,吸入氧浓度(FiO2)为0.4～0.5;PSV时的压力支持水平(PS)为8～16 cm H2O(即Pinsp-PEEP),最大吸气时间限制(Timax)为3 s,其余参数保持不变.监测潮气量(VT)、TI、每分通气量(MV)、吸气/呼吸周期时间比(TI/Ttot)和呼吸频率(RR),计算浅快呼吸指数(RSBI),并采集动脉血作血气分析.结果患者在接受PSV和PCV通气时的VT均明显高于CPAP时,RR逐渐减慢(P＜0.05);PCV时的MV明显低于PSV与CPAP时.PCV时的TI较PSV和CPAP时明显延长[(1.23±0.09)s与(1.06±0.11)s、(0.89±0.10)s,P＜0.05],PCV与PSV时的TI/Ttot较CPAP时减小;浅快呼吸指数(RSBI)从CPAP时的(78.2±4.9)breaths·min-1·L-1降至PSV时的(44.9±2.6)breaths·min-1·L-1和PCV时的(35.6±1.9)breaths·min-1·L-1(P＜0.05).PSV和PCV模式时的PaO2/FiO2明显高于CPAP时(264.5±72.3、273.1±71.2与221±56.4,P＜0.05),三种模式下的PaCO2均无显著性差异.结论与PSV相比,应用PCV治疗呼吸衰竭时通过预置适宜的TI及备用通气频率,能在与PSV相同的气道压的前提下提供相近的VT及MV;PCV不仅有助于调控患者的呼吸频率,提供必要的通气支持,还有利于减轻患者呼吸肌的作功.
