全麻肌松恢复期不同机械通气模式的研究

目的 :观察全麻患者在肌松恢复期用间歇正压通气 (IPPV)、同步间歇指令通气 (SIMV)、双水平压力正压通气 (Bi PAP)对自主呼吸恢复的影响。方法 :30例手术患者随机均分 3组。术中初始通气方式均为 IPPV,给最后一次肌松剂后将后两组的通气模式分别调整为 SIMV和 Bi PAP。不同时间点记录气道峰压 (Ppeak)、每分通气量 (MV)、呼气末二氧化碳分压 (PEt CO2 )和血气 ,观察给最后一次肌松剂至自主呼吸恢复的时间(L R S)。结果 :1给予最后一次肌松剂后和 T1 出现时 Bi PAP组的 Ppeak均明显低于 IPPV和 SIMV组(P均 <0 .0 1) ,TR=0 .75时 IPPV组的 Ppeak均明显低于 SIMV和 Bi PAP组 (P均 <0 .0 1) ;2 T1 恢复时Bi PAP组的 MV高于 IPPV组 (P<0 .0 5 ) ,T4 恢复、TR=0 .2 5、TR=0 .75时 SIMV和 Bi PAP组的 MV均明显高于 IPPV组 (P均 <0 .0 1) ;3TR=0 .2 5、TR=0 .75时 SIMV和 Bi PAP组的 PEt CO2 均低于 IPPV组 (P均 <0 .0 5 ) ;4拔管前 SIMV和 Bi PAP组的动脉二氧化碳分压 (Pa CO2 )均低于 IPPV组 (P均 <0 .0 5 ) ;5 SIMV组和Bi PAP组的 L R S均短于 IPPV组 (P均 <0 .0 5 )。结论 :SIMV和 Bi PAP具有不对抗患者自主呼吸、L R S短、Ppeak变化小、MV高、PEt CO2 低等优点 ,更适于全麻恢复期使用。 Bi PAP还具有 Ppeak     

ASV和SIMV对内源性呼气末正压和呼吸功影响的研究

目的:探讨适应性支持通气(ASV)和SIMV(同步间歇指令通气)在部分支持通气过程中对内源性PEEP(PEEPi)和呼吸功的影响。方法:30例有自主呼吸的危重症机械通气患者,在同样的分钟通气量和PEEP的设置下,先予以SIMV1(同步间歇指令通气)模式通气,45min后改为ASV模式通气,时间为45min,结束后再次回到SIMV2模式(参数设置与SIMV1一致),通气时间为45min。记录上述三个45min后的呼吸力学等参数。结果:ASV模式下的平台压下降明显,P<0.01;相对于SIMV1模式PEEPi的发生率为43.3%,ASV的发生率为20%,P<0.05;器械附加功(WOBimp)和吸气压力时间乘积(PTP)均小于SIMV1下的参数,P<0.01。结论:在部分支持通气过程中,ASV相对于SIMV,能明显改善高通气力学状态,有利于降低呼吸负荷和呼吸做功。     

有创-无创序贯性机械通气治疗老年肺内源性急性呼吸窘迫综合征随机对照临床研究

目的 评价有创-无创序贯性机械通气治疗老年肺内源性急性呼吸窘迫综合征(ARDS)患者的疗效及可行性.方法 32例老年肺内源性ARDS患者被随机分为序贯治疗组及常规治疗对照组,每组16例.两组均建立人工气道,以辅助/控制模式+呼气末正压(PEEP)+间隙性控制性肺膨胀(SI)方式通气24 h,随病情改善改用同步间歇指令通气(SIMV)+压力支持通气(PSV)+PEEP的方式.待"ARDS控制窗"出现,序贯组改换为无创正压通气(NIPPV),以持续气道正压(CPAP)方式通气并逐渐脱离呼吸机;对照组以SIMV+PSV+PEEP常规方式脱机.动态观察两组患者的通气及氧合指标,记录有创和总机械通气时间、呼吸机相关性肺炎(VAP)发生情况及住呼吸重症监护病房(RICU)的天数.结果 两组患者治疗前血气分析结果相仿(P均>0.05);序贯组有创通气时间[(4.6±1.0)d]、总机械通气时间[(12.7±4.0)d]、住RICU时间[(16±7)d]较对照组[分别为(21.9±9.0)d、(21.9±9.0)d、(29±13)d]明显缩短,VAP发生率[6.25%(1/16)]和病死率[25.00%(4/16)]也较对照组[分别为75.00%(12/16)、56.25%(9/16)]明显降低,差异均有统计学意义(P<0.05或P<0.01).结论 对老年肺内源性ARDS插管机械通气以ARDS控制窗为时机及时改用无创通气可显著改善其疗效.     

颈髓损伤后呼吸衰竭机械辅助呼吸模式比较

目的比较颈髓损伤后呼吸衰竭患者使用压力支持通气模式（PSV）与同步间歇指令通气模式（SIMV）的差异。方法观察34例患者在PsV与SIMV时血气分析、呼吸频率、心率、血压、患者主观舒适度的变化。结果在两种通气模式下，患者血压的变化无显著性差异（P〉0．05），血气pH值、PaO2、呼吸频率、心率、主观舒适度有非常显著性差异（P〈0．01），PaCO2有显著性差异（P〈0．05）。PSV模式优于SIMV模式。结论PSV模式较SIMV模式更适合颈髓损伤后呼吸功能不全时的治疗。     

肺透明膜病患儿机械通气时呼吸力学动态变化及临床意义

目的探讨肺透明膜病患儿机械通气时呼吸力学的变化特征及其临床意义。方法126例机械通气的肺透明膜病患儿,按照有无并发症分为有并发症组(43例)和无并发症组(83例)。于第1次机械通气后2、24、48和72h及第1次脱机前进行血气分析及呼吸力学指标监测。结果与机械通气2～72h比较,无并发症组和有并发症组患儿脱机前呼吸系统动态顺应性〔分别为(0.55±0.10)ml·cmH2O-1·kg-1和(0.43±0.10)ml·cmH2O-1·kg-1〕和每分通气量〔MV,分别为(0.65±0.10)L/min和(0.62±0.30)L/min〕均明显增加,氧合指数〔OI,OI=吸入氧浓度×平均气道压×100/动脉血氧分压,分别为(10.2±1.9)mmHg(1mmHg=0.133kPa)和(13.6±4.3)mmHg〕均明显降低。无并发症组呼吸系统动态顺应性和MV在机械通气后48h明显高于有并发症组;两组气道阻力和肺过度膨胀系数均无明显变化。呼吸系统动态顺应性与OI呈显著负相关(r=0.208,P<0.01),与MV呈显著正相关(r=0.218,P<0.01)。无并发症组均一次性脱机成功,脱机成功时呼吸系统动态顺应性平均为(0.55±0.10)ml·cmH2O-1·kg-1,MV平均为(0.65±0.20)L/min;有并发症组28例脱机失败,脱机失败时呼吸系统动态顺应性平均为(1.03±0.30)ml·cmH2O-1·kg-1,MV平均为(0.33±0.30)L/min。结论动态监测肺透明膜病患儿机械通气时呼吸力学的变化,可以判断肺部病变的严重程度,预测呼吸循环系统并发症发生的可能性,评估通气策略,掌握脱机指征。     

压力调节容量控制通气治疗危重支气管哮喘探讨

目的探讨压力调节容量控制通气(PRVC)模式治疗急性重症支气管哮喘的效果。方法47例重症哮喘患者被随机分为A组(25例)和B组(22例)。A组予PRVC通气,B组予SIMV PSV通气,比较两组患者治疗前后的动脉血气分析(ABGs)、呼吸力学、通气时间及住ICU时间。结果A组患者在使用机械通气(MV)后,ABGs明显改善(P<0·01),PIP、Pplat较B组降低,Cdyn优于B组,MV时间和住ICU时间均短于B组(P<0·05)。结论PRVC在治疗重症哮喘患者时,能够保持较低的PIP和Pplat,改善ABGs和Cdyn,缩短MV时间以及住ICU时间,是一种安全而有效的通气模式。     

Effects of spontaneous breathing during airway pressure release ventilation on renal perfusion and function in patients with acute lung injury

OBJECTIVE: Controlled mechanical ventilation can impair systemic and renal blood flow and function, which may be aggravated by respiratory acidosis. We hypothesized that partial ventilatory support using airway pressure release ventilation (APRV) with spontaneous breathing provides better cardiopulmonary and renal function than full ventilatory support using APRV without spontaneous breathing. DESIGN: Prospective randomized study. SETTING: Intensive care unit of a university hospital. PATIENTS: Twelve patients with acute lung injury (ALI). INTERVENTIONS: Airway pressure release ventilation with and without spontaneous breathing, maintaining either the same minute ventilation (V(E)) or the same airway pressure (Paw) limits. MEASUREMENTS: Systemic hemodynamics were estimated by double-indicator dilution, effective renal blood flow (ERBF) by para-aminohippurate, and glomerular filtration rate (GFR) by inulin clearance. RESULTS: Compared to APRV with spontaneous breathing, cardiac index (CI) was decreased when the upper Paw limit was increased to provide the same V(E) (4.26+/-1.21 l min(-1) m(-2)vs 3.72+/-0.99 l min(-1) m(-2); p<0.05) while CI was increased when Paw limits were held constant (4.91+/-1.41 l min(-1) m(-2); p<0.05). Effective renal blood flow and GFR were higher during APRV with spontaneous breathing (858+/-388 ml min(-1) m(-2) and 94+/-47 ml min(-1) m(-2)) than during APRV without spontaneous breathing and the same V(E) (714+/-236 ml min(-1) m(-2)and 82+/-35 ml min(-1) m(-2)) or the same Paw (675+/-287 ml min(-1) m(-2) and 80+/-41 ml min(-1) m(-2); p<0.05). Urine volume did not change. CONCLUSIONS: Spontaneous breathing during APRV was associated with better renal perfusion and function than APRV without spontaneous breathing applying either the same V(E) or the same Paw limits. Maintaining spontaneous breathing during ventilatory support may, therefore, be advantageous in preventing deterioration of renal function in patients with ALI.     

Interactive Simulation System for Artificial Ventilation on the Internet: Virtual Ventilator

Objective. To develop an interactive simulation system “virtual ventilator” that demonstrates the dynamics of pressure and flow in the respiratory system under the combination of spontaneous breathing, ventilation modes, and ventilator options. The simulation system was designed to be used by unexperienced health care professionals as a self-training tool. Methods. The system consists of a simulation controller and three modules: respiratory, spontaneous breath, and ventilator. The respiratory module models the respiratory system by three resistances representing the main airway, the right and left lungs, and two compliances also representing the right and left lungs. The spontaneous breath module generates inspiratory negative pressure produced by a patient. The ventilator module generates driving force of pressure or flow according to the combination of the ventilation mode and options. These forces are given to the respiratory module through the simulation controller. Results. The simulation system was developed using HTML, VBScript (3000 lines, 100 kB) and ActiveX control (120 kB), and runs on Internet Explorer (5.5 or higher). The spontaneous breath is defined by a frequency, amplitude and inspiratory patterns in the spontaneous breath module. The user can construct a ventilation mode by setting a control variable, phase variables (trigger, limit, and cycle), and options. Available ventilation modes are: controlled mechanical ventilation (CMV), continuous positive airway pressure, synchronized intermittent mandatory ventilation (SIMV), pressure support ventilation (PSV), SIMV + PSV, pressure-controlled ventilation (PCV), pressure-regulated volume control (PRVC), proportional assisted ventilation, mandatory minute ventilation (MMV), bilevel positive airway pressure (BiPAP). The simulation system demonstrates in a graph and animation the airway pressure, flow, and volume of the respiratory system during mechanical ventilation both with and without spontaneous breathing. Conclusions. We developed a web application that demonstrated the respiratory mechanics and the basic theory of ventilation mode.     

Reversal of the pattern of respiratory variation of Doppler inflow velocities in constrictive pericarditis during mechanical ventilation.

BACKGROUND: Spontaneous inspiration causes a characteristic decrease of the mitral valve (MV) and pulmonary venous (PV) flow velocities obtained by Doppler echocardiography in patients with constrictive pericarditis (CP). This has been explained by the decrement it causes in the intrathoracic pressure. Positive pressure ventilation (PPV) causes an increment of intrathoracic pressure with mechanical inspiration. Therefore the pattern of respiratory variation produced during PPV may differ from that seen during spontaneous breathing. OBJECTIVE: Our goal was to describe the effect of PPV on the pattern and magnitude of respiratory variation of MV and PV flow velocities in CP. METHODS: We performed intraoperative pulsed Doppler transesophageal echocardiography on 15 patients (13 men, mean age 52+/-15 years) with CP after general anesthesia and before sternotomy and pericardial stripping. The peak velocity and time-velocity integral (TVI) of the mitral inflow E and A waves and the PV systolic and diastolic waves were measured at onset of inspiration and expiration for 3 to 6 respiratory cycles. Respiratory phase was monitored with a heat-sensitive nasal thermistor. The percent change in Doppler flow velocities from mechanical inspiration (INS) to mechanical expiration (EXP) was calculated with the formula %change = INS - EXP / INS x 100. RESULTS: The peak velocity of the mitral inflow E wave was significantly higher during mechanical inspiration than expiration (57 +/-14.5 versus 47+/-13.9 cm/s, P<.001). This represented a percent change of 18%+/-7.9% from expiration to inspiration. The mean TVI of the mitral inflow E was also higher during mechanical inspiration than expiration (P = .02). The peak velocity of the PV D wave was higher during mechanical inspiration than expiration (39+/-17.8 versus 28+/-14.7 cm/s, P<.001). This represented a mean percent change of 28%+/-13.8%. The mean value of the TVI for the PV D wave was also significantly greater during mechanical inspiration than expiration (P <.05). CONCLUSIONS: Positive pressure ventilation reverses the pattern of respiratory variation of the MV and PV flow velocities in CP. The percent change in the peak velocities of the MV and PV flows produced by PPV is the same range reported in CP during spontaneous breathing.     

以改良格拉斯哥昏迷评分15分为切换点在有创-无创机械通气治疗慢性阻塞性肺疾病所致严重呼吸衰竭中的应用

目的 探讨以改良格拉斯哥昏迷评分(GCS)15分为切换点指导慢性阻塞性肺疾病(COPD)合并呼吸衰竭(呼衰)患者早期拔管改换无创机械通气的可行性,并评价其治疗效果.方法 选择接受气管插管和机械通气的COPD并呼衰患者,采用前瞻性对照研究方法,以2007年3月至2009年11月收治的20例患者为治疗组,采用同步间歇指令通气+压力支持通气(SIMV+PSV)方式行机械通气,待改良GCS评分达15分并稳定2 h的窗口期拔除气管导管,改用经鼻面罩PSV+呼气末正压(PEEP)通气,以后逐渐减小压力支持(PS)水平直至脱机;以2005年3月至2007年3月收治的19例患者为对照组,按常规机械通气及传统脱机方式脱机.动态观察两组患者机械通气前通气及氧合指标,接受有创机械通气时间、总机械通气时间、总住院时间、再插管及呼吸机相关性肺炎(VAP)发生例数.结果 两组机械通气前通气及氧合指标均无明显差异.治疗组较对照组有创通气时间(d:3.2±1.1比10.5±3.2)、总机械通气时间(d:4.8±2.5比10.5±3.2)、总住院时间(d:17±3比22±7)均明显缩短(均P＜0.01);VAP发生数减少(例:0比5,P＜0.01),再插管数稍增加,但无统计学意义(例:3比1,P＞0.05).结论 对COPD合并呼衰的机械通气患者,以改良GCS评分达15分稳定2 h窗口期为时机早期拔管改用经鼻面罩无创通气,可以显著改善患者的治疗效果.

Abstract：

Objective To estimate the feasibility and the efficacy of early extubation and the sequential non-invasive mechanical ventilation (MV) in severe respiratory failure of chronic obstructive pulmonary disease (COPD) with the improved Glasgow coma scale (GCS) score of 15 as the switching point. Methods By a prospective control study, 20 patients with COPD and respiratory failure who had undergone endotracheal intubation and MV from March 2007 to November 2009 were enrolled as treatment group.Invasive MV with synchronous intermittent mandatory ventilation and pressure support ventilation (SIMV+PSV) pattern were given to these patients. When the period of "improved GCS score of 15 standard" window period appeared and being kept for 2 hours, endotracheal tube was extubated, and nasal mask with PSV±positive end-expiratory pressure (PEEP) was used, followed by gradual decrease of the level of pressure support till weaning of MV. Nineteen patients who were treated with MV with ordinary way of weaning from March 2005 to March 2007 served as the control group. Prior to the MV, the ventilation and oxygenation index, the length of invasive MV, total MV time, total hospital stay, re-intubation and ventilator-associated pneumonia (VAP) occurred in the number of cases were observed and compared between two groups. Results There was no significant difference in the ventilation and oxygenation index prior to the MV. Compared with control group, in treatment group, the length of invasive ventilation (days: 3. 2±1.1 vs. 10. 5± 3. 2),the total duration of MV (days: 4. 8±2. 5 vs. 10. 5±3. 2), the length of hospital stay (days:17±3 vs. 22±7) were significantly shorter (all P＜0.01), and the incidence of VAP was significantly lower (cases: 0 vs.5, P＜ 0. 01), while the number of re-intubation was slightly higher but without statistical significance (cases:3 vs. 1, P＞0. 05). Conclusion The application of improved GCS score of 15 as the switching point with 2 hours as window period for early extubation and non-invasive nasal mask ventilation can significantly improve the therapeutic effect in patients with severe respiratory failure in COPD.     

机械通气治疗连枷胸合并呼吸衰竭16例

目的探讨连枷胸致呼吸衰竭的病理生理、机械通气治疗的指征、模式参数调节及撤离.方法总结16例采用机械通气治疗的连枷胸合并呼吸衰竭病例的临床治疗过程及转归.结果其中13例经机械通气4～14d后一次性成功脱机,转普通病房继续治疗5～1 3d后出院;3例死亡病例分别死于重度颅脑损伤及失血性休克.结论连枷胸如有机械通气指征,应尽早使用.机械通气模式可选用SIMV(同步间歇指令通气)+PSV(压力支持),宜选择偏高潮气量(10～12ml/kg),PEEP(呼气末正压)有利于病情恢复.浅快呼吸指数(f/VT)是目前撤机最有预测价值的指标.     

Respiratory depression under long-term sedation with sufentanil, midazolam and clonidine has no clinical significance

OBJECTIVE: Assessment of respiratory depression caused by long-term sedation with sufentanil, midazolam and clonidine. DESIGN: Retrospective assessment using data from a patient data management system. SETTING: University hospital anaesthesiological ICU. PATIENTS: Three hundred ninety-five surgical and trauma patients with an ICU stay of more than 48 h. INTERVENTION: None. MEASUREMENTS AND RESULTS: Arterial blood partial pressure of carbon dioxide (PCO2) was evaluated during mechanically assisted spontaneous ventilation (continuous positive airway pressure, synchronised intermittent mandatory ventilation, mandatory minute ventilation, bilevel positive airway pressure). Continuous sedation with sufentanil, midazolam or clonidine or a combination of those drugs was administered to achieve a Ramsay score between 2 and 4. Spontaneously breathing patients without continuous sedation and patients on controlled mechanical ventilation (and sedation) served as control groups. Mean arterial PCO2 from spontaneously breathing patients without continuous sedation was 39.5 +/- 7.3 torr compared with 42.7 +/- 6.8 torr under sufentanil (median 0.44 microg x kg(-1) x h(-1), 98 % of observations between 0.1 and 2.1 microg x kg(-1) x h(-1)), 41.5 +/- 6.1 torr under sufentanil (median 0.90 microg x kg(-1) x h(-1) (0.1-2.8)) plus midazolam (median 45 microg x kg(-1) x h(-1) (7-170)) and 39.8 +/- 5.6 torr under a combination of sufentanil (median 1.15 microg x kg(-1) x h(-1) (0.2-3.6)), midazolam (median 45 microg x kg(-1) x h(-1) (11-216)) and clonidine (median 1.3 microg x kg(-1) x h(-1) (0.2-2.5)). Mean arterial PCO2 from patients on controlled mechanical ventilation was 39.9 +/- 6.1 torr. CONCLUSION: Patients under continuous sedation with sufentanil exhibit a statistically significant rise in arterial PCO2, however this respiratory depression is only slight and has no clinical significance. Mechanically assisted spontaneous ventilation modes can safely be used under continuous sedation with sufentanil, midazolam or clonidine.     

SIMV加PSV／PSV切换结合高碳酸血症治疗慢性阻塞性肺疾病呼吸衰竭的临床研究

目的探讨同步间歇强制通气加压力支持通气／压力支持通气两种模式切换结合允许性高碳酸血症（PHC）技术治疗慢性阻塞性肺疾病急性呼吸衰竭的可行性和安全性。方法30例接受气管插管和机械通气的慢性阻塞性肺疾病（COPD）急性呼吸衰竭病例随机分为两组，各15例。研究组（A组）予小潮气量（7ml／kg）机械通气并实施PHC技术，对照组（B组）予常规潮气量（12ml／kg）机械通气。观察两组潮气量（VT）、分钟通气量（MV）、气道峰压（Ppeak）、平台压（Pplat）、动脉血气变化、机械通气时间、住院时间、呼吸机相关性肺炎（VAP）例数和气胸例数。结果治疗后2h、24hA组气道峰压Ppeak、平台压Pplat低于B组（P〈0．01）；机械通气2h、24hA组pn、Pa02值上升，PaC02值下降的速度滞后于B组，但与机械通气前比较，P〈0．05或P〈0．01；A、B两组机械通气时间为（7．2±3．2）d和（15．6±10．6）d，p〈0．01；住院时间为（10．2±3．2）d和（18．6±10．4）d，P〈0．05；发生呼吸机相关性肺炎2例和8例（p=0．022）；气胸0例和4例（p=0．049）。结论SIMV＋PSV／PSV切换联合PHC技术治疗慢性阻塞性肺疾病急性呼吸衰竭可以缩短机械通气时间和住院时间，降低机械通气的VAP发生率和气压伤风险。     

Effects of patient-triggered automatic switching between mandatory and supported ventilation in the postoperative weaning period

OBJECTIVE: To compare two ventilator settings in the postoperative weaning period. Patient-triggered automatic switching between controlled ventilation and supported spontaneous breathing (Automode, AM) was compared to synchronised intermittent mandatory ventilation (SIMV) with stepwise manual adjustment of mandatory frequency according to the breathing activity. DESIGN: Prospective clinical investigation. SETTING: Eighteen-bed intensive care unit in a university hospital. PATIENTS: Forty postoperative patients with healthy lungs who had undergone brain tumour surgery. INTERVENTIONS: Randomisation either to the AM or SIMV weaning procedure after entering the ICU. MEASUREMENTS AND RESULTS: Total weaning time and number of manipulations on the ventilator were observed. Cardiocirculatory and respiratory parameters were measured consecutively at five points during the weaning period. No significant differences were seen for cardiocirculatory parameters, airway pressures and oxygenation between the two groups. There was a trend to shorter weaning times with AM (136 +/- 46 min vs 169 +/- 68 min, n.s.), the average number of manipulations on the ventilator was lower (0.55 +/- 0.69 vs 5.05 +/- 1.19,p < 0.001) and arterial partial pressure of carbon dioxide (PaCO2) levels showed fewer variations in the late phase of the weaning period (39.5 +/- 3.1 vs 38.3 +/- 7.2, p < 0.001 for differences in variance). CONCLUSIONS: Automatic, patient-triggered switching between controlled and supported mode of ventilation can be used for postoperative weaning of neurosurgical patients with healthy lungs. Compared to a SIMV weaning procedure, fewer manipulations on the ventilator are necessary and individual adaptation of ventilation seems to be more accurate.     

吸入沙丁胺醇对呼吸衰竭患者容积标限压力控制通气时通气参数的影响

目的　探讨在容积标限压力控制 (VTPC)通气时吸入支气管扩张剂沙丁胺醇后对机械通气参数的影响。方法　 10例平均年龄为 (6 8± 5 )岁的呼吸衰竭患者均接受气管插管与机械通气支持治疗 ;采用Newport e5 0 0型呼吸机 ,并实施定容型通气 (VCV) 30 min,潮气量 (VT)为 8～ 10 ml/ kg;测定气道阻力 (Raw)和静态顺应性 (Cst)以及通气参数的变化 ,包括气道峰压 (PIP)、平台压 (Pplat)、充气时间 (Tinflate)、吸气峰流速(PIF)、呼气峰流速 (PEF)和平均吸气流速 (VT/ Tinflate)。随后转为 VTPC通气 30 m in,并同样记录上述参数。通过同轴吸入装置吸入沙丁胺醇 6 0 0 μg后重复 VCV和 VTPC通气 ,并记录上述通气参数。结果　 10例患者的 Cst为 (38.4± 2 .7) ml/ cm H2 O,Raw为 (2 0 .1± 2 .0 ) cm H2 O· L- 1 · s- 1 。VTPC时 PIP和 VT/ Tinflate较 VCV时显著降低 (P均 <0 .0 5 ) ,PIF则显著增高 ,两种通气时的 Pplat无显著性差异 ,分别为 (2 2 .1± 0 .9) cm H2 O和(2 3.0± 1.2 ) cm H2 O(P>0 .0 5 )。吸入沙丁胺醇后患者的 Raw均显著降低 ,而 Cst无明显变化 ,VCV时的 PIP有所降低 ,但 Pplat无变化 ;VTPC时的 PIP和 Pplat与吸入前比较无明显改变 ,但 PIF和 PEF出现显著增高 ,Tinflate则相应缩短 (P均 <0 .0 5     

气管插管并人工机械通气在危重肺心病呼吸衰竭患者救治中的作用和方法探讨

目的　探讨气管插管并人工机械通气在危重肺心病呼吸衰竭患者救治中的作用和方法。方法　 2 86例危重肺心病呼吸衰竭患者均采用在纤支镜引导下经鼻、口的方式进行气管插管并行人工机械通气 ,多功能呼吸机先采用持续麻醉和辅助 /控制 (A/C)通气模式 ,待病情稳定后再改为间歇指令通气 (SIMV) 压力支持通气 (PSV) ,最后单用SIMV脱机。结果　成功救治 2 34例 ( 81 8% ) ,死亡 5 2例 ( 18 2 % ) ,并发症 72例 ( 2 6 9% )。结论　气管插管并人工机械通气是救治危重肺心病呼吸衰竭患者十分有效的方法     

慢性阻塞性肺疾病机械通气治疗呼吸参数的变化及意义

目的 通过慢性阻塞性肺疾病（COPD）患者机械通气治疗中呼吸参数的变化，进一步探讨机械通气的作用。方法 42例COPD合并慢性呼吸衰竭急性加重的患者应用无创或有创机械通气（CPAP、SIMV模式）治疗，比较机械通气前后呼吸参数的变化及其意义。结果 42例患者机械通气后所选定的呼吸参数均有不同程度的好转改变，无创通气及有创通气治疗后呼吸频率（RR）、呼出潮气量（EVT）、分钟通气量（MV）、平均气道压（MAP）与治疗前比较差异均有显著性（P〈0.01）。结论 无创或有创机械通气治疗COPD合并慢性呼吸衰竭急性加重的患者，有助于呼吸肌疲劳的改善，克服气道阻力和肺顺应性降低，从而使各项呼吸参数均得到改善。     

In vivo physiologic comparison of two ventilators used for domiciliary ventilation in children with cystic fibrosis.

OBJECTIVE: Home noninvasive mechanical ventilation (NIMV) is used with increasing frequency for the treatment of patients with respiratory failure caused by cystic fibrosis, yet the optimal mode of ventilation in such children is unknown. We compared the physiologic short-term effects of two ventilators with different modes (one pressure support and the other assist control/volume-targeted [AC/VT]) commonly used for domiciliary ventilation. DESIGN: Prospective, randomized, crossover comparison of two ventilators with different modes. SETTING: Tertiary pediatric university hospital. PATIENTS: Eight children with cystic fibrosis (age, 11-17 yrs) and chronic respiratory failure (pH 7.4 +/- 0.0; PaO2, 57.5 +/- 7.5 torr; PaCO2, 46.1 +/- 2.5 torr), naive to NIMV. INTERVENTIONS: Two 20-min runs of pressure support and AC/VT ventilation were performed in random order, each run being preceded and followed by 20 mins of spontaneous breathing. MEASUREMENTS: Flow and airway pressure and esophageal and gastric pressures were measured to calculate esophageal (PTPes) and diaphragmatic pressure-time product (PTPdi) and the work of breathing. RESULTS: The two NIMV sessions significantly improved blood gas variables and increased tidal volume with no change in respiratory rate. Indexes of respiratory effort decreased significantly during the two modes of NIMV compared with spontaneous breathing, with PTPdi/min decreasing from 497.8 +/- 115.4 cm H2O x sec x min(-1) during spontaneous breathing to 127.8 +/- 98.3 cm H2O x sec x min(-1) and 184.3 +/- 79.8 cm H2O x sec x min(-1), during AC/VT and pressure support, respectively (p <.0001), and the work of breathing decreasing from 1.83 +/- 0.12 J.L-1 during spontaneous breathing to 0.48 +/- 0.32 J.L-1 and 0.75 +/- 0.30 J.L-1, during AC/VT and pressure support, respectively (p <.0001). In addition, the effect of AC/VT ventilation was significantly superior to pressure support judged by PTPes and the work of breathing, but this result was explained by three patients who adapted extremely well to the AC/VT ventilation, with the disappearance of ventilator triggering, in effect adopting a controlled mode. There was a correlation between the improvement in PTPdi/min or the work of breathing and patient's subjective impression of comfort during the AC/VT ventilation. CONCLUSIONS: In awake, stable children with cystic fibrosis, both AC/VT and pressure support unloaded the respiratory muscles. The disappearance of ventilator triggering occurred in a subgroup of patients during AC/VT ventilation, and this explained the good tolerance and the superiority of this mode in the present study.     

早产儿呼吸衰竭同步机械通气治疗的呼吸力学评价

目的　探讨同步间歇性指令通气 (SIMV )在早产儿机械通气中的临床意义。方法　 4 2例机械通气的早产儿随机分成两组 ,SIMV组 2 4例 ,间歇性指令通气 (IMV)组 18例 ,观察两组呼吸机参数、呼吸力学参数变化 ,以及并发症的发生率及镇静剂的使用次数。结果　上机 2 h后吸气峰压 (PIP)、呼气潮气量 (VTexp)、呼吸系统顺应性 (Crs)、气道阻力 (Raw) ,12 h后吸氧浓度 (Fi O2 ) SIMV组均明显优于 IMV组 ,2 4 h氧合指数(OI) SIMV组明显少于 IMV组 ;镇静剂的使用次数 SIMV组少于 IMV组 ,两组差异均有显著性 (P<0 .0 5或P<0 .0 1) ;并发症的发生率两组差异无显著性 (P均 >0 .0 5 )。结论　早产儿呼吸衰竭机械通气时使用 SIMV模式较 IMV能更快降低 Fi O2 、PIP、OI,较快改善肺功能 ,减少镇静剂和肌松剂的使用率。     

Positive end-expiratory pressure modulates local and systemic inflammatory responses in a sepsis-induced lung injury model

OBJECTIVE: Previous animal studies have shown that certain modes of mechanical ventilation (MV) can injure the lungs. Most of those studies were performed with models that differ from clinical causes of respiratory failure. We examined the effects of positive end-expiratory pressure (PEEP) in the setting of a clinically relevant, in vivo animal model of sepsis-induced acute lung injury ventilated with low or injurious tidal volume. METHODS: Septic male Sprague-Dawley rats were anesthetized and randomized to spontaneous breathing or four different strategies of MV for 3 h at low (6 ml/kg) or high (20 ml/kg) tidal volume (V(T)) with zero PEEP or PEEP above inflection point in the pressure-volume curve. Sepsis was induced by cecal ligation and perforation. Mortality rates, pathological evaluation, lung tissue cytokine gene expression, and plasma cytokine concentrations were analyzed in all experimental groups. RESULTS: Lung damage, cytokine synthesis and release, and mortality rates were significantly affected by the method of MV in the presence of sepsis. PEEP above the inflection point significantly attenuated lung damage and decreased mortality during 3 h of ventilation with low V(T) (25% vs. 0%) and increased lung damage and mortality in the high V(T) group (19% vs. 50%). PEEP attenuated lung cytokine gene expression and plasma concentrations during mechanical ventilation with low V(T). CONCLUSIONS: The use of a PEEP level above the inflection point in a sepsis-induced acute lung injury animal model modulates the pulmonary and systemic inflammatory responses associated with sepsis and decreases mortality during 3 h of MV.