机械通气与膈肌萎缩

机械通气已成为急性、慢性重症呼吸衰竭患者的必要治疗手段,但机械通气可导致呼吸机相关的膈肌功能障碍,并与通气患者撤机困难密切相关.对动物模型和机械通气患者的研究证实控制通气后膈肌失用性萎缩:膈肌肌块减小、肌纤维萎缩和肌球蛋白重链表达降低.膈肌萎缩出现快速且程度远较外周骨骼肌明显.肌萎缩源于蛋白分解加剧,和(或)蛋白合成减少.失用时膈肌细胞内数种参与收缩蛋白降解的蛋白酶水解途径被活化,钙调蛋白酶系统和泛素蛋白酶途径被认为是最主要的途径.本文就失用性肌萎缩蛋白分解的机制及信号转导途径综述如下.     

机械通气导致的膈肌功能异常及其预防

呼吸机导致的膈肌功能异常(ventilator-induceddiaphragm dysfunction,VIDD)是机械通气的不良反应之一.在临床上VIDD可造成患者吸气能力显著降低、撤机困难,严重影响治疗效果.VIDD病理表现为肌纤维受损、肌肉萎缩和肌纤维重塑等膈肌病变.探讨呼吸机导致膈肌病变的分子生物学机制以及VIDD的预防和治疗措施是近年来研究的热点.现介绍VIDD的研究进展、防治方法及今后的研究方向.     

床旁肺部超声膈肌功能评估脓毒性休克机械通气患者指导撤机

目的 研究床旁肺部超声膈肌功能评估脓毒性休克机械通气患者指导撤机的应用效果.方法 选取本院2018年9月-2019年9月收治的80例脓毒性休克机械通气患者,按照随机数表法将其分为对照组与观察组,每组40例,对照组应用浅快呼吸指数指导撤机,观察组应用床旁肺部超声膈肌功能评估指导撤机,对比两组患者的撤机成功率、机械通气时间以及并发症发生情况(再插管、肺部气压伤、呼吸机相关性肺炎).结果 观察组患者的撤机成功率(77.5%)高于对照组(62.5%),机械通气时间(6.3±1.6)d短于对照组(8.5±2.7)d,且并发症发生率(5.0%)低于对照组(20.0%),各组对比差异均有统计学意义(P<0.05).结论 床旁肺部超声膈肌功能评估脓毒性休克机械通气患者指导撤机的应用效果显著,可明显提高撤机成功率,缩短机械通气时间,且可降低并发症发生率,值得临床推行.     

膈肌超声对重症患者机械通气撤机的预测价值

目的:评价膈肌超声对机械通气(MV)患者撤机结果的预测价值。方法:选取行MV时间 48h的重症患者41例,在符合撤机条件后使用T管进行自主呼吸试验(SBT),于SBT 30min时使用床旁超声测量患者右侧躯体的膈肌移动度(DE)和膈肌厚度,并计算膈肌增厚率(DTF),根据撤机成败与否将患者分为撤机成功组(26例)和撤机失败组(15例)。采用受试者工作特征(ROC)曲线评价膈肌功能超声指标对撤机的指导价值。结果:撤机成功组患者DE及DTF高于撤机失败组(均P 0. 05)。分别选取1. 08 cm和30%作为DE和DTF的截断值,其预测撤机成功的敏感度分别为80. 77%和65. 38%,特异度分别为80. 00%和60. 00%,ROC曲线下面积分别为0. 751(95%CI:0. 571～0. 932)和0. 668(95%CI:0. 484～0. 852)。结论:膈肌功能超声监测可作为重症医学科MV患者撤机能力的预测指标,对撤机具有较好的指导价值。     

超声膈肌功能评估对重症肺炎伴呼吸衰竭患者机械通气撤机的指导意义

目的 分析超声膈肌功能评估对重症肺炎伴呼吸衰竭患者机械通气撤机的指导意义。方法 选择2019年8月至2022年8月我院接受机械通气治疗的重症肺炎伴呼吸衰竭患者98例,根据撤机结局分为撤机成功为观察组72例和撤机失败者为对照组26例;筛查影响撤机失败的危险因素,对膈肌移动度和膈肌增厚率对重症肺炎伴呼吸衰竭患者机械通气撤机失败的预测。结果 急性生理与慢性健康指数(APACHEⅡ)评分升高、腹胀、通气时间延长、膈肌移动度降低、膈肌增厚率降低是重症肺炎伴呼吸衰竭患者撤机失败的危险因素(P<0.05)。ROC分析结果膈肌移动度、膈肌增厚率单一及联合预测重症肺炎伴呼吸衰竭患者机械通气撤机失败的AUC分别为0.709(95%CI:0.591～0.827)、0.716(95%CI:0.598～0.834)、0.782(95%CI:0.675～0.889)。结论 超声膈肌功能可用于分析重症肺炎伴呼吸衰竭患者机械通气后的撤机结局,膈肌增厚率、膈肌移动率对患者机械通气后撤机失败率预测具有意义。     

膈肌超声在机械通气患者撤机结果预测中的应用价值

目的评价膈肌超声对ICU机械通气(mechanical ventilation, MV)病人撤机结果预测中的应用价值。方法选取在2018年12月至2019年4月期间收住安徽医科大学第一附属医院高新院区重症医学科符合纳入标准21例患者,撤离呼吸机后行超声检查膈肌,根据撤机成功与否,将患者分为撤机成功组和撤机失败组。结果撤机成功组膈肌活动度(diaphragm excursion,DE)、吸气末膈肌厚度(diaphragmatic thickness at the end of inspiration, DTei)、呼气末膈肌厚度(diaphragmatic thickness at the end of expiration, DTee)、膈肌增厚率(diaphragm thickening fraction, DTF)均明显高于撤机失败组,差异有统计学意义,ROC曲线提示DE、DTei、DTee、DTF均可预测撤机是否成功。结论超声监测膈肌,有助于预测机械通气患者撤机结果。     

肺性脑病行机械通气撤机的护理体会

目的 回顾性分析肺性脑病行机械通气撤机后的临床护理及其体会.方法 回顾性研究我院收住该类患者采取包括行机械通气的有效措施以及撤机后所采取的各种护理方法.结果 48例患者在撤机后有43例1次性成功撤机,陆续好转出院.未成功1次撤机的5例中有2例发生呼吸肌疲劳、2例并发呼吸机相关肺炎、1例出现撤机困难,经再次应用呼吸机治疗后有3例成功脱机,死亡2例.结论 有效的气道管理、正确的自主呼吸试验、早期营养支持、心理疏导、避免镇静剂及肌肉松弛剂的应用等综合处理是肺性脑病撤离呼吸机后的必要护理措施.     

机械通气患者撤机困难的危险因素及预防对策

目的探讨引起机械通气患者撤机困难的相关因素及预防对策。方法根据撤机困难诊断标准判断180例机械通气治疗中撤机困难发生例数,比较撤机成及撤机困难两组患者年龄、性别、APACHE评分、机械通气时间、病程、血清白蛋白水平、合并呼吸机相关性肺炎、心理因素、等方面的差异。结果 180例机械通气治疗患者中撤机困难40例(22.22%),logistic回归分析显示机械通气撤机困难的独立危险因素为:老年患者、呼吸机相关性肺炎、白蛋白水平低、心理因素,其OR值分别为3.34、3.05、2.98、2.65。结论撤机困难是多种因素共同作用的结果,临床医生应合理调节机械通气方式及各种参数,同时进行有效抗感染、营养支持、呼吸肌功能锻炼、实施心理支持以提高撤机成功率。     

序贯健肌操联合床旁B超监测膈肌预测老年慢性阻塞性肺疾病急性加重期患者机械通气撤机的临床观察

目的 探讨序贯健肌操联合床旁B超监测膈肌预测老年慢性阻塞性肺疾病(慢阻肺)急性加重期患者机械通气撤机情况的效果.方法 60例老年慢阻肺急性加重期患者,所有患者接受序贯健肌操联合床旁B超监测膈肌,观察分析其机械通气撤机成功率及撤机指标〔膈肌电活动(Edi)、口腔闭合压(P0.1)及呼吸浅快指数(f/Vt)〕情况.结果 6...     

呼吸机引起的横膈功能障碍的研究进展

呼吸机引起的横膈功能障碍是由机械通气后膈肌张力负荷下降、神经刺激减少、肌肉萎缩、结构损伤和肌纤维重塑等多因素引起的横膈肌收缩能力不全的临床现象,主要表现为脱机困难。机械通气时间、通气模式和潮气量等对呼吸机引起的横膈功能障碍的发生有显著影响。通过治疗原发病、合理通气、刺激膈神经和抗氧化干预等方法可以对其进行有效防治。     

Effects of mechanical ventilation on diaphragm function and biology.

The pathophysiological mechanisms of weaning from mechanical ventilation are not fully known, but there is accumulating evidence that mechanical ventilation induces inspiratory muscle dysfunction. Recently, several animal models have provided potential mechanisms for mechanical ventilation-induced effects on muscle function. In patients, weaning difficulties are associated with inspiratory muscle weakness and reduced endurance capacity. Animal studies demonstrated that diaphragm force was already decreased after 12 h of controlled mechanical ventilation and this worsened with time spent on the ventilator. Diaphragmatic myofibril damage observed after 3-days controlled mechanical ventilation was inversely correlated with maximal diaphragmatic force. Downregulation of the diaphragm insulin-like growth factor-I and MyoD/myogenin messenger ribonucleic acid occurred after 24 h and diaphragmatic oxidative stress and increased protease activity after 18 h. In keeping with these findings, diaphragm fibre atrophy was shown after 12 h and reduced diaphragm mass was reported after 48 h of controlled mechanical ventilation. These animal studies show that early alterations in diaphragm function develop after short-term mechanical ventilation. These alterations may contribute to the difficulties in weaning from mechanical ventilation seen in patients. Strategies to preserve respiratory muscle mass and function during mechanical ventilation should be developed. These may include: adaptation of medication, training of the diaphragm, stabilisation of the catabolic state and pharmacotherapy.     

血必净对严重脓毒症并发呼吸机相关性肺炎发病率的影响

目的观察血必净注射液对严重脓毒症患者呼吸机相关性肺炎发生的影响。方法严重脓毒症并发呼吸衰竭需要机械通气的成年住院患者100名，随机分为血必净治疗组和常规对照组，观察两组病人呼吸机相关性肺炎的发生率，28天病死率，ICU住院时间，呼吸机治疗时间以及抗生素使用天数。结果血必净治疗组呼吸机相关性肺炎的发生率，病死率降低，ICU住院时间，呼吸机治疗时间以及抗生素使用天数缩短，有统计学差异。结论血必净可以降低严重脓毒症患者发生呼吸机相关性肺炎的发病率。     

超声评估膈肌功能及其临床应用进展

膈肌是最重要的呼吸肌,承担着约75％的呼吸做功。可通过超声测量膈肌厚度、膈肌移动度等指标来评估膈肌功能,进而辅助临床医师作出相应决策。膈肌超声在预测机械通气患者脱机结局、协助诊断COPD、预测全麻术后肌松残余、预测术后肺部并发症、评估康复训练效果等方面有潜在价值。本文就膈肌的超声评估方法及临床应用情况进行综述,以期指导临床医生应用超声相关指标来评估膈肌功能,希望对临床工作提供帮助。     

呼吸机引起的膈肌功能障碍与脱机肺水肿的研究进展

膈肌功能障碍和脱机引起的肺水肿是导致脱机失败的两个重要原因。膈肌功能障碍会降低膈肌收缩力量,使肺通气减少,引起脱机失败;脱机时胸内负压增大,通过增加静脉回流和左心室后负荷,导致脱机肺水肿和呼吸窘迫。本文对膈肌功能障碍和脱机引起的肺水肿的发生机制、诊断方法以及治疗策略进行综述。     

控制性机械通气对大鼠膈肌功能的影响

目的 探讨控制性机械通气(CMV)对大鼠膈肌功能的影响,了解不适当控制性机械通气与膈肌功能不全和脱机困难的关系.方法 将24只雄性SD大鼠按随机数字表法分为3组:正常对照组、18 h CMV组和24 h CMV组.后两组分别给予18 h和24 h CMV,并测定膈肌跨膈压(Pdi)、最大跨膈压(Pdimax)、膈肌肌电图(EMGdi)等指标和膈肌肌球蛋白重链(MHC)表型的改变.两样本组间均数比较用t检验,多组间均数差异性比较采用单因素方差分析.结果 与对照组比较,18、24 Hcmv组Pdimax分别为[(8.98±0.55、6.12±0.53、14.92±0.16)cm H2O,1 cm H2O=0.098 kPa],实验组均低于对照组,差异有统计学意义(F=82.35,P<0.01);实验组EMGdi的中心频率和高低频比值均低于对照组;在最大刺激频率(100 Hz)下18、24 h CMV组的膈肌肌张力[(84.11±0.43、52.65±0.64)N]较对照组[(98.13±0.50)N]低,差异有统计学意义(F=15.02,P<0.01);同时MHC2A比例下降;24 h CMV组大鼠膈肌肌纤维的电镜下病理改变为:膈肌出现肌原纤维排列疏松、脂肪滴和空泡增多,个别出现线粒体肿胀、空化,嵴减少.结论 短期CMV即可导致膈肌功能失调和形态改变;机械通气,特别是CMV诱导的膈肌功能障碍可能是引起临床上一些患者脱机困难的重要原因之一.     

Diaphragmatic fatigue and breathing pattern during weaning from mechanical ventilation in COPD patients

The medium-term outcome of weaning from mechanical ventilation in COPD patients is not easy to anticipate because a respiratory fatigue may eventually develop. We evaluated the diaphragmatic function and the breathing pattern during 40 weaning trials on 15 patients ventilated after acute respiratory failure. We formed two groups according to the success (group B, n = 18) or failure (group A, n = 19) of the medium-term attempt (group A/less than 10 hours; group B/more than 12 hours). Provided the patients showed the classic weaning criteria (tidal volume greater than 5 ml/kg, respiratory frequency less than 30 breaths per minute, PaO2 greater than 50 mm Hg), the study of the breathing pattern did not allow differentiation between the groups. However, the transdiaphragmatic pressure (Pdi) and the Pdimax, which gave an indication of the power of diaphragm contraction, dropped early in the group that could not stand weaning, with an increase in the Pdi/Pdimax ratio. In addition, this same group showed a diaphragmatic dysfunction attested for by a frequent negative gastric pressure associated with or shortly preceded by an abdominal paradoxic motion.     

Diaphragmatic strength during weaning from mechanical ventilation

Respiratory muscle weakness is considered to be a factor in the inability to wean from mechanical ventilation. To assess this possibility, the present study examined the mechanical behavior of the diaphragm by measuring the change in transdiaphragmatic pressure (delta Pdi) during weaning. Nine "T-piece" weanings were carried out in seven patients with prior weaning failure and were terminated with the development of hypercapnia, hypoxemia, or severe tachypnea. Serial measurements of delta Pdi during these weans revealed that (1) in no case was there a decrease in delta Pdi at termination of weaning, and (2) in the subgroup of patients whose weaning failed because of hypercapnia, the increase in arterial carbon dioxide tension (mean increase of 12 mm Hg) was associated with a significant increase in delta Pdi, from the beginning (21.1 +/- 12.1 cm H2O) to the end (24.8 +/- 13.4 cm H2O) of the trial (p less than 0.05). We conclude that failure to wean in these patients, in particular the development of carbon dioxide retention, was not due to failure of the diaphragm as a pressure generator.     

Ultrasonographic evaluation of liver/spleen movements and extubation outcome

INTRODUCTION: The diaphragm plays a pivotal role in weaning and successful extubation. We hypothesized that ultrasonographic evaluation of the movements of the diaphragm by measuring liver/spleen displacement during spontaneous breathing trials is a good predictor for extubation outcome. PATIENTS AND METHODS: The studied subjects were intubated patients receiving mechanical ventilation who were scheduled to be extubated. The displacement of liver/spleen was measured by ultrasonography before extubation. The patients were classified into a success group (SG) or failure group according to the extubation outcome. The baseline data and organ displacements in these two groups were analyzed. The sensitivity and specificity for the mean organ displacements and weaning parameters to predict successful extubation were calculated. RESULTS: We included 55 patients, 32 of whom (58%) were in the SG. The baseline data are similar for these two groups, but the mean values of liver and spleen displacements were higher in the SG. Using a cutoff value of 1.1 cm, the sensitivity and specificity to predict successful extubation were 84.4% and 82.6%, respectively, better than traditional weaning parameters in this study. CONCLUSION: The displacement of the liver/spleen, measured by ultrasonography, is a good predictor for extubation outcome.     

Nichtinvasive Beatmung nach Extubation

The effectiveness of non-invasive ventilation (NIV) in the management of difficult or prolonged weaning has most convincingly been shown for hypercapnic respiratory failure, mainly due to COPD. In this context three different clinical scenarios should be distinguished. First NIV as a systematic technique to facilitate early extubation leading to a decrease in ventilator-associated pneumonia and mortality, second, NIV as a preventive strategy immediately after planned extubation in patients showing risk factors for recurrent respiratory failure, and third, NIV application as a rescue therapy in patients with apparent respiratory failure after planned extubation, revealing the potential to avoid re-intubation in hypercapnic patients with pre-existing respiratory disorders. In non-COPD patients with hypoxemic respiratory failure after extubation, NIV cannot generally be recommended. NIV application within the weaning process requires a high degree of experience in this technique and progress to urgent re-intubation must not be delayed.     

Decline in diaphragm thickness and clinical outcomes among patients with sepsis

BackgroundThe decline in the diaphragm thickness is common among patients with sepsis. The purpose of this study is to examine the relationship between the decline in diaphragm thickness as assessed by ultrasonography and various outcomes in septic patients.MethodsThis prospective study included patients with sepsis whose diaphragm thickness was measured during inspiration (DTinsp) and expiration (DTexp) using ultrasonography on days 1, 3, 5, 7, 10, and 14 of admission in the ICU and thereafter weekly measurements until discharge or death.ResultsThe study included 70 (45 male) patients with sepsis [mean (SD) age = 55.91(14.08) years]. The mean (SD) DTinsp and DTexp (mm) on day-1 were 2.84 (0.32) and 2.33(0.27), respectively. During the hospital stay, there was a decline in DTinsp and DTexp. The decline in DTinsp and DTexp on days 3, 5, and 7 was significantly higher among patients with difficult weaning, non-survivors, and worse 90-day outcomes. Early decline (from day-1 to day-3) in diaphragm thickness predicted difficult weaning, in-hospital mortality, and worse 90-day outcome.ConclusionsAmong patients with sepsis, the decline in diaphragm thickness detected by ultrasonography is associated with worse in-hospital and short-term post-discharge outcomes. The role of early decline in diaphragm thickness on ultrasonography as a marker of worse outcomes needs further evaluation.