急性呼吸窘迫综合征患者机械通气时内源性呼气末正压的测定及其意义

目的:研究急性呼吸窘迫综合征(ARDS)患者机械通气时内源性呼气末正压的发生率,探讨内源性呼气末正压的临床意义.方法:前瞻性应用德尔格Evita 4和Evita 2 dura呼吸机测定34例ARDS患者机械通气时内源性呼气末正压.结果:34例急性呼吸窘迫综合症患者机械通气时内源性呼气末正压发生率为100%,内源性呼气末正压范围为2～15 cm H2O,平均为5.41±2.12 cm H2O,随着病情好转,内源性呼气末正压下降.结论:ARDS患者机械通气时普遍存在内源性呼气末正压,故此对ARDS患者机械通气时随时要注意内源性呼气末正压,减少气压伤的发生率.     

呼吸力学监测:指导机械通气决策

需要机械通气的患者通常存在严重的呼吸力学异常。应用机械通气时,首先需要对基础疾病的呼吸力学异常进行评估,然后根据相应的特点应用机械通气。通过合理应用吸气和呼气相压力、呼吸流量、容量和时间节律,调控相关患者的呼吸努力、吸气末与呼气末的肺容量位置和呼吸中枢驱动,达到优化机械通气应用的目的。急性呼吸窘迫综合征(acute respiratory distress syndrom,ARDS)作为肺氧合功能异常性疾病的代表,其机械通气的主要目标是维持肺的开放与氧合功能,避免肺过度牵张与呼吸机相关肺损伤。慢性阻塞性肺疾病作为气流受限性疾病的代表,其机械通气的主要目标是维持合适的通气的同时,避免导致肺动态过度充气和内源性呼气末正压的进一步恶化,调控合适的呼吸中枢驱动水平。临床日常工作中常态化开展呼吸力学监测,对优化机械通气应用有重要的意义。     

不同风险评估系统和炎性指标对重症老年机械通气患者撤机结果的预测价值

目的探讨不同风险评估系统及炎性指标对重症老年机械通气患者撤机结果的预测价值分析。方法选取四川省达州市中西医结合医院2016年10月-2018年12月ICU收治的136例需要机械通气的老年患者作为研究对象,于撤机前对所有患者进行APACHE II、SAPS II、MODS、SOFA、CPIS风险评估,并检测患者血清炎性指标(PCT、CRP、PTX-3、HRG)。按拔管结果分为撤机成功组和撤机困难组,使用ROC曲线分析各风险评估系统结果及炎性指标对拔管结果预测的敏感性及特异性。结果撤机成功76例,失败60例。撤机成功组APACHE II、SAPS II、MODS、SOFA、CPIS等评分均显著低于撤机困难组,组间比较差异有统计学意义(P<0.05);风险评估系统APACHE II、SAPS II、MODS、SOFA、CPIS预测机械通气的ICU患者预后情况均具有较高效能,其中SAPS II的AUC值较高,其cut-off值为26.63,敏感性为89.53%,特异性为85.05%。炎性指标PCT、CRP、PTX-3、HRG预测机械通气的ICU患者预后情况均具有较高效能,其中PTX-3的AUC值最大,显著高于其它各指标(P<0.05),其cut-off值为33.82,敏感性为68.42%,特异性为93.33%。SAPS II评分和PTX-3作为联合指标预测机械通气的ICU患者预后的敏感度为94.74%,特异度为86.67%。结论风险评估系统APACHE II、SAPS II、MODS、SOFA、CPIS均可用于预测机械通气的ICU患者预后,其中SAPS II较优。炎性指标PTX-3预测机械通气的ICU患者预后效果好,优于PCT、CRP、HRG等指标。SAPS II评分联合PTX-3预测老年机械通气的ICU患者预后效果更佳。     

腹腔间室综合征伴ARDS患者的机械通气护理

报告了25例腹腔间室综合征伴急性呼吸窘迫综合征患者机械通气的方法和护理特点。根据患者自主呼吸的能力选择持续气道内正压-压力支持-呼气末正压通气或同步间歇指令-压力支持-呼气末正压通气模式,由专职气道护理人员进行气道护理。根据腹内压、气道阻力和肺顺应性随时调整呼吸机参数,采用密闭式吸痰管快速吸痰,并给予有效的气道湿化和肺部物理治疗。本组急性生理学和慢性健康状况评分均值为18.3±4.1,且均>15分,并发2个以上器官功能障碍者13例,发生呼吸机相关性肺炎4例。治愈19例,死亡6例。     

老年急性脑卒中患者合并呼吸衰竭的机械通气治疗

目的 探讨肺保护性通气策略（LPVS）在老年急性脑卒中合并呼吸衰竭患者救治中的意义。方法 通过时55例老年急性脑卒中合并呼吸衰竭患者实施机械通气的临床资料进行回顾性分析，对比观察常规机械通气（n=27）和LPVS（n=28）对其动脉血气、呼吸力学、血流动力学、机械通气并发症、颅内压和病死率等的影响。结果LPVS和常规机械通气均能明显改善患者的动脉血气指标，两组差异无统计学意义（P〉0.05）；LPVS对改善呼吸力学、血流动力学和降低机械通气并发症、病死率等均优于常规机械通气，两组差异有统计学意义（P〈0.05）；LPVS对老年急性脑卒中患者的颅内压无不良影响。结论老年急性脑卒中合并呼吸衰竭患者机械通气可采用LPVS，设置小潮气量、限制经肺压和加用呼气末正压。同时应加强专科治疗，积极纠正循环和代谢功能障碍。     

呼气末正压在治疗急性呼吸窘迫综合症中的应用及护理

综述在治疗急性呼吸窘迫综合症病人时使用呼气末正压的理论基础，以及近年来急性呼吸窘迫综合症机械通气策略中呼气末正压的应用。提出选择最佳呼气末正压的方法、最新观点和需要解决的问题。阐述运用呼气末正压在治疗急性呼吸窘迫综合症中的护理监护。     

开胸术后并发呼吸窘迫综合征机械通气患者的气道监护

总结开胸术后并发急性呼吸窘迫综合征(ARDS)机械通气患者的气道监护经验。对18例开胸术后并发ARDS患者进行原因分析。早期诊断,早期给予机械通气治疗,实施相应的呼吸道监护。给予小潮气量、低呼气末正压通气,随时调整通气模式和呼吸参数,加强呼吸道的护理。15例顺利脱机康复出院,3例死于多器官功能衰竭。     

不同水平呼气末正压对急性心源性肺水肿预后的影响

目的:探讨不同水平呼气末正压对急性心源性肺水肿预后的影响.方法:将65例急性心源性水肿行机械通气的患者随机分成低呼气末正压组(A组)和高呼气末正压组(B组),比较两组血气、CVP、BP、HR、尿量、x线胸片的变化和并发症.结果:通气治疗2 h后两组血气的变化,两组通气时间、不良事件的发生率的比较均无显著性差异(P>0.05),但通气过程中两组CVP、BP、HR的变化有显著性差异(P<0.05).结论:呼气末正压水平的选择对急性心源性肺水肿机械通气治疗的预后无明显影响,低水平呼气末正压为更安全而有效的通气策略.     

呼气末正压在治疗急性呼吸窘迫综合症中的应用及护理

综述在治疗急性呼吸窘迫综合症病人时使用呼气末正压的理论基础,以及近年来急性呼吸窘迫综合症机械通气策略中呼气末正压的应用。提出选择最佳呼气末正压的方法、最新观点和需要解决的问题。阐述运用呼气末正压在治疗急性呼吸窘迫综合症中的护理监护。     

大剂量氨溴索对急性呼吸窘迫综合征患者呼吸力学和氧化应激的影响

目的: 研究大剂量氨溴索对急性呼吸窘迫综合征(ARDS)患者机械通气过程中在呼吸力学和氧化应激的影响.方法:46例ARDS机械通气患者,在机械通气过程中分别采用安慰剂(生理盐水)和大剂量氨溴索 + 生理盐水治疗,同时监测患者内源性呼气末正压(PEEPi)、静态顺应性(Cst)和气道阻力( R )的变化;并检测血清丙二醛(MDA)、谷胱甘肽(GSH)含量、超氧化物歧化酶(SOD)活性及总氧化能力(TAO)水平. 结果:氨溴索治疗组患者PEEPi, R和MDA显著降低, Cst、GSH、SOD和TAO水平提高.结论:临床应用大剂量盐酸氨溴索能改善ARDS患者呼吸力学状况,并能减轻患者氧化应激水平.     

Effects of extrinsic positive end-expiratory pressure on mechanically ventilated patients with chronic obstructive pulmonary disease and dynamic hyperinflation

Objective To examine the circulatory and respiratory effects of extrinsic positive end-expiratory pressure (PEEPe) in patients with chronic obstructive pulmonary disease (COPD) and dynamic hyperinflation during controlled mechanical ventilation.Design Different levels of PEEPe were applied randomly in mechanically ventilated patients with COPD and dynamic hyperinflation.Setting Respiratory Intensive Care Unit of a University Hospital.Patients 9 patients with acute respiratory failure and dynamic hyperinflation due to acute exacerbation of COPD.Interventions PEEPe 35%, 58% and 86% of intrinsic PEEP (PEEPi) were applied.Measurements and results Using flow-directed pulmonary artery catheters hemodynamic measurements were obtained, while simultaneously lung volumes, airflows and airway pressures were recorded. In order to estimate alveolar pressures (P_alv), rapid airway occlusions during passive expiration were also performed. At no level of PEEPe were significant changes in cardiac output, gas exchange variables, dead space, airways inflation resistances and respiratory system static end-inspiratory compliance observed. At high level of PEEPe central venous, mean pulmonary arterial and pulmonary capillary wedge pressures were increased significantly. All but one patient were flow-limited during passive expiration. PEEPe 86% of PEEPi caused a significant increase in end-expiratory lung volume and total PEEP. Iso-volume pressure-flow curves showed volume-dependence expiratory flow limitation in 2 patients, while in 8 patients volume-dependence of critical driving pressure (P_alv-mouth pressure) that decreased flows was also observed.Conclusions The effects of PEEPe on iso-volume flow and hence on lung mechanics and hemodynamics, depend on many factors, such as airways resistances, lung volumes and airway characteristics, making the patient response to PEEPe unpredictable.     

Decreased serial scores of severe organ failure assessments are associated with survival in mechanically ventilated patients; the prospective Maastricht Intensive Care COVID cohort

BackgroundThe majority of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are admitted to the Intensive Care Unit (ICU) for mechanical ventilation. The role of multi-organ failure during ICU admission as driver for outcome remains to be investigated yet.Design and settingProspective cohort of mechanically ventilated critically ill with SARS-CoV-2 infection.Participants and methods94 participants of the MaastrICCht cohort (21% women) had a median length of stay of 16 days (maximum of 77). After division into survivors (n = 59) and non-survivors (n = 35), we analysed 1555 serial SOFA scores using linear mixed-effects models.ResultsSurvivors improved one SOFA score point more per 5 days (95% CI: 4–8) than non-survivors. Adjustment for age, sex, and chronic lung, renal and liver disease, body-mass index, diabetes mellitus, cardiovascular risk factors, and Acute Physiology and Chronic Health Evaluation II score did not change this result. This association was stronger for women than men (P-interaction = 0.043).ConclusionsThe decrease in SOFA score associated with survival suggests multi-organ failure involvement during mechanical ventilation in patients with SARS-CoV-2. Surviving women appeared to improve faster than surviving men. Serial SOFA scores may unravel an unfavourable trajectory and guide decisions in mechanically ventilated patients with SARS-CoV-2.     

呼吸体操治疗重度COPD呼气流速受限的临床价值

【目的】探讨呼吸体操方法治疗重度至极重度慢性阻塞性肺疾病（COPD）呼气流速受限的临床价值。【方法】选择稳定期重度至极重度COPD患者40例,随机分为呼吸体操组（A组）20例和无呼吸体操组（B组）20例。在常规治疗的基础上,A组患者给予针对COPD呼气流速受限的呼吸体操8周,B组患者不给予呼吸体操锻炼,分别测定并比较两组8周前后MRC呼吸困难（MRC）评分、最大呼气压力（MEP）、最大吸气压力（MIP）及肺通气功能。【结果】A组呼吸康复后的MRC评分显著低于8周前（P〈0．01）,MEP和MIP显著高于8周前（P〈0．01）,A组8周前后差值与B组8周前后差值比较有显著性差异（P〈0．01）;A组呼吸康复后最大通气量（MVV）显著高于8周前（P〈0．01）,其他肺功能指标8周前后比较差异均无显著性（P〉0．05）;A组MVV8周前后差值与B组8周前后差值比较有显著性差异（P〈0．01）。【结论】呼吸体操能明显改善重度至极重度COPD患者的呼吸困难,增加运动耐力和呼吸肌功能。     

改良饮水方式在无创机械通气患者中的应用

目的评价改良饮水方式在呼吸衰竭患者无创机械通气时的应用效果。方法选择2010年10月至2011年10月解放军总医院呼吸科监护病房使用无创机械通气患者80例,按随机数字表法随机分为观察组40例和对照组40例,两组性别、年龄、急性生理学与慢性健康状况评分Ⅱ（APACHEII）比较,差异无统计学意义（P〉0．05）。观察组采用改良饮水方法,即饮水期间不断开无创机械通气;对照组采取传统饮水方式,即饮水时直接摘下面罩饮水。记录两组患者的脉氧饱和度、呼吸频率、心率、平均血压、口渴评分、呛咳和呼吸困难症状。结果观察组在饮水毕、饮水后5rain、饮水后30min脉氧饱和度始终高于对照组（94．8±2．5比91．8±3．4,95．1±2．0比92．4±3．2,96．0±1．9比93．4±2．9）（t值分别为-4．641,-4．650,-4．896;P均〈0．05）,且呛咳、呼吸困难等症状发生率明显低于对照组（10．0％比45．0％,5．0％比22．5％）（X^2分别为12．288,5．165;P均〈0．05）。饮水结束后30min,对照组口渴评分明显上升,与观察组比较差异有统计学意义（1．97±0．65比1．30±0．60）（t=4．792,P〈0．05）。结论在无创机械通气患者护理中采用改良饮水方式效果满意,优于传统饮水方式。     

Assessment and monitoring of flow limitation and other parameters from flow/volume loops

Flow/volume (F/V) spirometry is routinely used for assessing the type and severity of lung disease. Forced vital capacity (FVC) and timed vital capacity (FEV₁) provide the best estimates of airflow obstruction in patients with asthma, chronic obstructive pulmonary disease (COPD) and emphysema. Computerized spirometers are now available for early home recognition of asthma exacerbation in high risk patients with severe persistent disease, and for recognition of either infection or rejection in lung transplant patients. Patients with severe COPD may exhibit expiratory flow limitation (EFL) on tidal volume (VT) expiratory F/V (VTF/V) curves, either with or without applying negative expiratory pressure (NEP). EFL results in dynamic hyperinflation and persistently raised alveolar pressure or intrinsic PEEP (PEEP_i). Hyperinflation and raised PEEP_i greatly enhance dyspnea with exertion through the added work of the threshold load needed to overcome raised pleural pressure. Esophageal (pleural) pressure monitoring may be added to VTF/V loops for assessing the severity of PEEP_i: 1) to optimize assisted ventilation by mask or via endotracheal tube with high inspiratory flow rates to lower I : E ratio, and 2) to assess the efficacy of either pressure support ventilation (PSV) or low level extrinsic PEEP in reducing the threshold load of PEEP_i. Intraoperative tidal volume F/V loops can also be used to document the efficacy of emphysema lung volume reduction surgery (LVRS) via disappearance of EFL. Finally, the mechanism of ventilatory constraint can be identified with the use of exercise tidal volume F/V loops referenced to maximum F/V loops and static lung volumes. Patients with severe COPD show inspiratory F/V loops approaching 95% of total lung capacity, and flow limitation over the entire expiratory F/V curve during light levels of exercise. Surprisingly, patients with a history of congestive heart failure may lower lung volume towards residual volume during exercise, thereby reducing airway diameter and inducing expiratory flow limitation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Physiological responses to arm exercise in difficult to wean patients with chronic obstructive pulmonary disease

Objectives To evaluate the effects of arm exercise with or without support of mechanical ventilation on breathing pattern, respiratory muscle pressure output, and ratings of dyspnea and arm discomfort in difficult-to-wean patients with COPD. Design and setting Prospective, controlled, physiological study in a respiratory ICU.Patients Eight tracheostomized difficult-to-wean patients.Intervention Patients performed an incremental and an endurance arm exercise while breathing through a trach collar or while receiving pressure support ventilation.Measurements and results Breathing pattern, mechanics, arterial saturation, heart rate, and subjective ratings of dyspnea and arm discomfort were measured at baseline, at the end, and 30 min after exercise. Exercise during pressure support ventilation was found to result in higher peak workload (incremental testing) than exercise during trach collar. Moreover, compared to incremental and endurance testing during trach collar, incremental and endurance testing during pressure support ventilation resulted in greater tidal volume, and lower respiratory rate, lower pressure output from the respiratory muscles, and lower work of breathing. Exercise-induced worsening of dyspnea and arm discomfort during trach collar was similar to the corresponding values recorded during pressure support ventilation. Conclusion In tracheostomized difficult-to-wean patients with COPD arm exercise performed during unassisted respiration (trach collar) causes greater increases in respiratory rate and in respiratory muscle pressure output than arm exercise performed during pressure support ventilation. Exercise-induced dyspnea and arm discomfort are similar during assisted and nonassisted respiration.     

Respiratory weakness is associated with limb weakness and delayed weaning in critical illness

OBJECTIVE: Although critical illness neuromyopathy might interfere with weaning from mechanical ventilation, its respiratory component has not been investigated. We designed a study to assess the level of respiratory muscle weakness emerging during the intensive care unit stay in mechanically ventilated patients and to examine the correlation between respiratory and limb muscle strength and the specific contribution of respiratory weakness to delayed weaning. DESIGN: Prospective observational study. SETTING: Two medical, one surgical, and one medicosurgical intensive care units in two university hospitals and one university- affiliated hospital. PATIENTS: A total of 116 consecutive patients were enrolled after >or=7 days of mechanical ventilation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Maximal inspiratory and expiratory pressures and vital capacity were measured via the tracheal tube on the first day of return to normal consciousness. Muscle strength was measured using the Medical Research Council score. After standardized weaning, successful extubation was defined as the day from which mechanical ventilatory support was no longer required within the next 15 days. The median value (interquartile range) of maximal inspiratory pressure was 30 (20-40) cm H2O, maximal expiratory pressure was 30 (20-50) cm H2O, and vital capacity was 11.1 (6.3-19.8) mL/kg. Maximal inspiratory pressure, maximal expiratory pressure, and vital capacity were significantly correlated with the Medical Research Council score. The median time (interquartile range) from awakening to successful extubation was 6 (1-17) days. Low maximal inspiratory pressure (hazard ratio, 1.86; 95% confidence interval, 1.07-3.23), maximal expiratory pressure (hazard ratio, 2.18; 95% confidence interval, 1.44-3.84), and Medical Research Council score (hazard ratio, 1.96; 95% confidence interval, 1.27-3.02) were independent predictors of delayed extubation. Septic shock before awakening was significantly associated with respiratory weakness (odds ratio, 3.17; 95% confidence interval, 1.17-8.58). CONCLUSIONS: Respiratory and limb muscle strength are both altered after 1 wk of mechanical ventilation. Respiratory muscle weakness is associated with delayed extubation and prolonged ventilation. In our study, septic shock is a contributor to respiratory weakness.     

呼气负压技术检测呼气流速受限在慢性阻塞性肺疾病中的应用

目的:应用呼气负压技术(NEP)检测慢性阻塞性肺疾病(COPD)患者的呼气流速受限(EFL)。方法:94例COPD患者在坐位及卧位时应用NEP方法检测EFL,即在患者潮气呼吸时于患者口部施加一个-5cmH2O的负压,通过比较施加负压前后的潮气流速-容积曲线来检测EFL。采用EFL五分法与经典的一秒钟用力呼气量(FEV1)方法进行比较。结果:55例COPD患者在坐位及卧位时均存在EFL;23例患者仅于卧位时存在EFL;16例患者坐位及卧位均无EFL。EFL五分法与经典FEV1方法判断肺功能损害程度较一致。EFL五分法与COPD患者的主观呼吸困难分级有更好的相关性。结论:①COPD患者在平静呼吸时EFL普遍存在;②NEP提供了一种简便、快速、无创的方法来检测EFL;③EFL五分法与COPD患者的呼吸困难分级有很好的相关性。     

Manual compression of the abdomen to assess expiratory flow limitation during mechanical ventilation

Purpose

The aim of this study was to evaluate the manual compression of the abdomen (MCA) during expiration as a simple bedside method to detect expiratory flow limitation (EFL) during daily clinical practice of mechanical ventilation (MV).

Methods

We studied 44 semirecumbent intubated and sedated critically ill patients. Flow-volume loops obtained during MCA were superimposed upon the preceding breaths and recorded with the ventilator. Expiratory flow limitation was expressed as percentage of expiratory tidal volume without any increase in flow during MCA (MCA [%V_T]). In the first 13 patients, MCA was validated by comparison with the negative expiratory pressure (NEP) technique. Esophageal pressure changes during MCA and intrinsic positive end-expiratory pressure were also recorded in all the patients.

Results

Manual compression of the abdomen and NEP agreed in all cases in detecting EFL with a bias of −0.16%. Percentage of expiratory tidal volume without any increase in flow during MCA is highly correlated with percentage of expiratory tidal volume without any increase in flow during NEP (n = 13, P < .0001, r² = 0.99) and intrinsic positive end-expiratory pressure (n = 44, P < .001, r² = 0.78), with a good repeatability (n = 44; within-subject SD, 5.7%) and reproducibility (n = 13; within-subject SD, 2.41%). Two third of the patients were flow limited, among whom one third had no previously known respiratory disease.

Conclusions

Manual compression of the abdomen provides a simple, rapid, and safe bedside reliable maneuver to detect and quantify EFL during mechanical ventilation.