摘要
目的 研究慢性阻塞性肺疾病急性加重期（AECOPD）呼吸衰竭患者无创机械通气时不同压力支持（PS）水平对呼吸生理学参数、人机同步性的影响.方法 入选15例住呼吸科重症监护病房（RICU）的AECOPD呼吸衰竭患者,均需无创机械通气.分别随机给予受试者5、10、15 cm H2O（1 cm H2O=0.098 kPa）水平的PS,在每个PS水平通气30 min后进行2 min的连续参数测量,取其均值.记录每个水平的生理学参数,并计算无效触发指数.结果 15例AECOPD患者,高PS水平（15 cm H2O）的无效触发指数、潮气量（VT）、分钟通气量（VE）、VT变异率、呼吸机吸气时间（TI）、呼气时间（TE）、漏气量（leak）均显著高于低PS水平[5 cm H2O,无效触发指数：（33.8±9.1）%比（8.0±6.0）%,VT（ml）：626±203比339±115,VE（L/min）：11.1±4.7比7.7±2.7,VT变异率：（32.6±15.5）%比（11.3±6.9）%,TI（s）：1.14±0.31比0.76±0.15,TE（s）：2.49±0.44比1.87±0.28,leak（L/min）：8.28±4.86比2.22±1.58,均P〈0.05],而高PS水平时呼吸机呼吸频率（RRvent,次/min）显著低于低PS水平（17±3比23±3,P〈0.05）;在低水平PS支持下,无效触发指数与TI呈显著正相关（r=0.62,P〈0.05）.PS水平由低至高变化时,无效触发指数变化率（Δ无效触发）的回归分析显示：Δ无效触发与ΔTI呈显著正相关,与ΔVT呈显著负相关（R2=0.88,P=0.000）.结论 ①低水平PS时,患者的无效触发主要与TI延长有关.②高水平PS可显著增加患者的VE、VT,降低RRvent,同时无效触发显著升高;无效触发指数的增加可以通过患者TI的延长、VT变化的个体差异得到解释,而与leak无关.③即使使用Shape-signal切换机制,高水平无创压力支持通气下的AECOPD患者仍保持较高的无效触发指数.
Objective To evaluate the effects of different levels of pressure support （PS） during noninvasive pressure support ventilation （NPPV） on physiological variables, patient-ventilator synchronicity in patients with acute exacerbation chronic obstructive pulmonary disease （AECOPD） and hypercapnic respiratory failure. Methods Fifteen hypercapnic respiratory failure AECOPD patients requiring NPPV in respiratory intensive care unit （RICU） were enrolled. Three different PS levels of 5, 10, 15 cm H2O （1 cm H2O=0.098 kPa） were applied randomly in all the 15 patients. At each PS level the patient was ventilated for 30 minutes, whereas physiological variables, ineffective effort （IE） expressed as IE index were recorded within the last 2 minutes. Results The IE index, tidal volume （VT）, minute ventilation （VE）, coefficient of variation of VT, ventilator inspiratory time （TI）, expiratory time （TE）, leak volume at 15 cm H2O PS level were significantly higher than those at 5 cm H2O level [IE index： （33.8±9.1）% vs. （8.0±6.0）%, VT （ml）： 626±203 vs. 339±115, VE （L/min）： 11.1±4.7 vs. 7.7±2.7, coefficient of variation of VT： （32.6±15.5）% vs. （11.3±6.9）%, TI （s）： 1.14±0.31 vs. 0.76±0.15, TE （s）： 2.49±0.44 vs. 1.87±0.28, leak volume （L/min）： 8.28±4.86 vs. 2.22±1.58, all P〈0.05], while the ventilator respiratory rate [（17±3） breaths/min] was lower at 15 cm H2O PS level than that at 5 cm H2O level [（23±3） breaths/min, P〈0.05]. At 5 cm H2O level, the IE index was positively correlated with TI （r=0.62, P〈0.05）. Furthermore, the increase in IE index followed by PS level increase was correlated negatively with the change of VT （ΔVT） and positively with that of the TI （ΔTI, R2=0.88, P=0.000）. Conclusions ①The IE at low assistance is associated with prolonged TI. ②High PS level can significantly increase VE and VT, and reduce the ventilator respiratory rate. However, high PS level also lead to higher IE than low level. The factors favoring a higher increase in IE index as PS level increased include a less increase in VT and a higher increase in TI. However, an increase in leak volume is not associated with an elevated incidence of IE. ③IE is high at high PS level during NPPV, even the Shape-signal is used as a trigger mechanism.
出处
《中国危重病急救医学》
CAS
CSCD
北大核心
2010年第7期405-409,共5页
Chinese Critical Care Medicine
基金
武警医学院资助项目（WY200815）
关键词
无创机械通气
肺疾病
阻塞性
慢性
无效触发
呼吸衰竭
人机同步性
Noninvasive pressure support ventilation
Chronic obstructive pulmonary disease
Ineffective effort
Respiratory failure
Patient-ventilator synchronicity
