咪达唑仑在机械通气中的应用

目的　观察咪达唑仑在机械通气患者中的应用 ,评价其镇静效果及可能的不良反应。方法　 3 0例符合观察要求的机械通气患者 ,以微量泵持续静脉注入咪达唑仑。负荷剂量 8～ 12 μg kg ,维持量 5～ 12 μg·kg- 1 ·h- 1 ,用药时间不超过 72h。观察镇静情况 (Ramsayscore ,RS评分 )、血压、脉搏、血氧饱和度、呼吸频率的变化及停药后的拔管情况。结果　所有患者在给咪达唑仑负荷剂量后 ,RS从 1级下降至 3～ 5级 ,达到很好的镇静要求 ,且在维持量下能保持良好的镇静水平 ,有效率 10 0 % ;患者的血压在用药前后和维持过程中均无明显差异 ;心率与血氧饱和度在给负荷剂量后 5min与治疗前有显著差异 (P <0 .0 5 ) ;自主呼吸频率用药后与用药前对比有非常明显的改善 (P <0 0 1) ;符合拔管条件的患者停药后都能很快拔除气管导管。结论　咪达唑仑静脉微量泵推注能很好地应用于ICU中机械通气的患者 ,镇静效果好、循环影响小、能保持患者的自主呼吸与机械通气协调 ,减少人机对抗 ,用药 72h不会造成拔管延迟等不良反应     

有创机械通气治疗重症SARS

为探讨有创机械通气治疗严重急性呼吸综合征(severe acute respiratory syndrome,SARS)的优缺点及适应症,本文分析我院SARS ICU2003年5月15日到6月18日收治的4例应用有创通气治疗的重症SARS患者的资料。4例患者中有1例痊愈,3例死亡,其中2例死于SARS所致缺氧,另外1例死于缺氧及继发的室性心律失常、感染性休克和肾功能衰竭。结果显示有创机械通气对于改善重症SARS患者的氧合是一种有效方法,但患者存活率不高,并可能增加医护人员的交叉感染,故应用时需权衡利弊。     

Neonatal mechanical ventilation: Indications and outcome

Subjects:Age <1-month; mechanically ventilated; not having suspected metabolic disorders or congenital anomalies; excluding postoperative patients.Methods:Neonates consecutively put on mechanical ventilation during the study period (October 2011 to November 2013) enrolled. Primary disease of the neonates along with complications present listed. Clinical and laboratory parameters analyzed to find the predictors of mortality.Results:Total 300 neonates were ventilated. 52% were male. Mean age, weight, and gestational age were 21 ± 62 h, 2320 ± 846.2 g, and 35.2 ± 4.9 weeks, respectively. 130 (43%) neonates died. Respiratory distress syndrome (RDS) (31.1%), sepsis (22.7%), and birth asphyxia (18%) were the most common indications for ventilation. Mortality in ventilated patients with sepsis, pneumonia, RDS or birth asphyxia was 64.7%, 60%, 44.6%, and 33.3%, respectively. Weight <2500 g, gestation <34 weeks, initial pH <7.1, presence of sepsis, apnea, shock, pulmonary hemorrhage, hypoglycemia, neutropenia, and thrombocytopenia were significantly associated with mortality (P < 0.05). Resuscitation at birth, seizures, intra ventricular hemorrhage, pneumothorax, ventilator-associated pneumonia, PO₂, or PCO₂ did not have a significant association with mortality. On logistic regression, gestation <34 weeks, initial pH <7.1, pulmonary hemorrhage, or shock were independently significant predictors of mortality.Conclusions:Weight <2500 g, gestation <34 weeks, initial arterial pH <7.1, shock, pulmonary hemorrhage, apnea, hypoglycemia, neutropenia, and thrombocytopenia were significant predictors of mortality in ventilated neonates.     

经纤维支气管镜支气管肺泡灌洗对机械通气治疗溺水后呼吸衰竭的影响

目的观察经纤维支气管镜支气管肺泡灌洗对淹溺淡水污水后出现呼吸衰竭给予机械通气治疗的患者的疗效影响。方法35例淹溺污水后行机械通气治疗的患者,其中男性23例,女性12例;年龄18～67岁,平均年龄42.5岁。入院48 h内在机械通气状态下行经纤维支气管镜支气管肺泡灌洗治疗,比较入院时和入院48 h两组呼吸生理、呼吸力学及临床指标。结果抢救成功32例,死亡3例。与入院时相比,入院48 h氧合指数、呼吸频率、体温、吸气峰压等呼吸生理、呼吸力学及临床指标明显改善,比较上述两组指标,差异均有统计学意义(P<0.05),术中指脉氧监测无明显下降。结论经纤维支气管镜支气管肺泡灌洗在机械通气状态下治疗溺水所致呼吸衰竭的患者安全有效。     

不同容量机械通气对盐酸诱导ARDS大鼠脑损伤的作用

目的研究不同容量机械通气对急性呼吸窘迫综合征（ARDS）大鼠脑损伤的作用机制。方法将30只sD大鼠随机分为对照组、盐酸＋高潮气量组（HCL＋HV组）和盐酸＋低潮气量组（HCL＋LV组）,每组10只。两个模型组麻醉后均从气管注入0．1mol盐酸。HCL＋LV组通气容量为6ml／kg体重,通气末正压为3cmH20;HCL＋Hv组通气容量为15ml／kg体重,通气末正压为0cm H2O。各组大鼠连续通气6h后处死,行肺泡灌洗并取肺及脑海马组织进行病理观察,并用ELISA法检测脑组织中的相关指标。对照组麻醉后无需特殊处理即行相关指标检测。结果模型组大鼠可见肺组织中ARDS病理改变。海马组织中间质血管轻度扩张充血。与对照组比较,HCL＋HV组和HCL＋Lv组的脑组织中还原型谷胱甘肽（GSH）含量明显降低（P均〈0．05）,而巨噬细胞炎症蛋白-2（MIP．2）、S-l008及IL．6含量明显升高（P均〈0．05）。与HCL＋HV组相比,HCL＋LV组脑组织中MIP-2、IL．6及S-100β含量明显降低（P均〈0．05）。结论HCL诱导的ARDS大鼠在机械通气情况下有远隔部位脑损伤的表现,低容量机械通气对ARDS大鼠的脑损伤有协同保护作用。     

A morphometric model of lung mechanics for time-domain analysis of alveolar pressures during mechanical ventilation

In this study we propose, and implement in the time domain, an anatomically consistent model of the respiratory system in critical care conditions that allows us to evaluate the impact of different ventilator strategies as well as of constrictive pathologies on the time course of acinar pressures and flows. We discuss the simplifications of the original Horsfield structure (Horsfield, K., [et_al.] Models of the human bronchial tree. J. Appl. Physiol. 31:207–217, 1971), which were needed to enable the model implementation. The model has a binary tree structure including large airways represented as a combination of wall compliance and laminar resistance, small airways that have the same arrangement but can be heterogeneously constricted, and alveolar compartments that are viscoelastic second-order models to represent the stress adaptation behavior of lung tissue. We have described patient–ventilator interactions modeling the ventilator and the endotracheal tube. In conclusion this model makes it possible to investigate realistically the effect of homogeneous versus heterogeneous constrictive pathologies and the impact of different ventilatory patterns on pressure and flow distribution at the acinar level in the mechanically ventilated patient. © 2002 Biomedical Engineering Society. PAC2002: 8719Uv, 8719Rr, 8710+e     

Determinants of plasma copeptin: A systematic investigation in a pediatric mechanical ventilation model

Copeptin, the C-terminal part of the arginine vasopressin precursor peptide, holds promise as a diagnostic and prognostic plasma biomarker in various acute clinical conditions. Factors influencing copeptin response in the critical care setting are only partially established and have not been investigated systematically. Using an in vivo infant ventilation model (Wistar rats, 14 days old), we studied the influence of commonly occurring stressors in critically ill children. In unstressed ventilated rats basal median copeptin concentration was 22 pmol/L. In response to respiratory alkalosis copeptin increased 5-fold, while exposure to hypoxemia, high PEEP, hemorrhage, and psycho-emotional stress produced a more than 10-fold increase. Additionally, we did not find a direct association between copeptin and acidosis, hypercapnia, and hyperthermia. Clinicians working in the acute critical care setting should be aware of factors influencing copeptin plasma concentrations. Moreover, our results do have implications for animal studies in the field of stress research.     

支气管灌洗联合机械通气治疗重症哮喘28例

目的探讨支气管灌洗联合机械通气在治疗重症哮喘中的作用。方法对35例常规治疗后病情缓解不明显的重症哮喘患者,建立人工气道接受机械通气治疗。选择其中机械通气4～6 h后症状改善不够明显、气道阻力仍较高的28例患者,经纤维支气管镜行支气管灌洗,清除呼吸道痰栓,并局部注射药物治疗。结果28例患者在支气管灌洗后临床症状均有较明显好转,气道阻力逐步下降,血气不断改善。28例患者中,25例最终治愈(89.29%),3例死亡;其中1例死于严重感染,2例死于心力衰竭。脱机时间平均(3.7±2.0)d;痊愈时间平均(6.1±2.0)d。结论支气管灌洗联合机械通气是治疗重症哮喘的有效措施。     

流量波形触发技术在慢性阻塞性肺疾病合并撤机困难患者中的应用研究

目的 观察不同流量触发机制对撤机困难的呼吸衰竭患者在压力支持通气(PSV)时通气参数的影响.方法 呼吸衰竭患者23例,其中男性16例,女性7例,年龄(68±6)岁.基础疾病均为慢性阻塞性肺疾病(COPD).所有患者均为接受有创人工气道(气管插管/汽管造口)及机械通气支持1周以上者,在治疗过程中病情稳定准备进行自主呼吸试验(spontaneous breathing trial,SBT).分别在标准流量触发(2L/min)和流量波形触发机制下通气支持30min(PS10cmH2),监测患者的呼吸力学参数[包括潮气量(VT)、呼吸频率(RR)、分钟通气量(MV)、气道闭合压(Pα1)、浅快呼吸指数(RSBI)和压力时间乘积(PTPt)等]及动脉血气分析,并观察流量波形触发技术对撤机的影响.结果 2例患者因生理学参数不稳定而终止SBT试验.其余21例在采用流量波形触发PSV支持30 min后,RR、MV和RSBI均出现显著增加(P＜0.05),但VT、Pα1却无明显变化.继续通气支持24h后,RR、MV和RSBI与采用流量波形触发PSV支持30 min时相比无显著改变,PTPt和Pα1却呈显著降低,动脉血二氧化碳分压(PaCO2)也逐渐降低.采用流量波形触发PSV支持3～7 d后,21例患者成功撤机.结论 流量波形触发技术能显著减少COPD呼吸衰竭患者的自主吸气做功,改善人机同步性,提高撤机成功率.     

无创呼吸机在已经出现呼吸肌疲劳但不伴有呼吸衰竭的AECOPD患者中的应用价值

目的：探讨无创呼吸机在已经出现呼吸肌疲劳但不伴有呼吸衰竭的慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)患者中的应用价值。方法：选取2013年12月至2015年12月我院收治的138例已经出现呼吸肌疲劳但不伴有呼吸衰竭的AECOPD患者作为研究对象,按照随机数字表法将患者分为研究组和对照组,每组69例。对照组患者进行抗感染、吸氧、祛痰、维持电解质酸碱平衡等常规治疗,研究组在对照组基础上加用无创呼吸机治疗。综合比较两组患者治疗前后肺功能、血气分析情况、呼吸肌功能、呼吸困难程度及患者耐受性的差异。结果：治疗前,两组FEV1、FVC、FEV1/FVC等比较均无统计学差异(P>0.05);治疗后,研究组FEV1、FEV1/FVC比对照组高(P<0.05)。治疗前,两组血气分析各指标比较均无统计学差异(P>0.05);治疗后30 min,两组PO2、PCO2、SaO2、pH等各指标均比治疗前明显改善P<0.05)。治疗后,组间血气分析指标比较无统计学差异(P>0.05)。研究组呼吸肌功能评分高于对照组(P<0.05),mMRC评分低于对照组(P<0.05)。患者耐受性好,无退出治疗病例。结论：无创呼吸机在治疗已经出现呼吸肌疲劳但不伴有呼吸衰竭的AECOPD疗效好,能有效患者改善呼吸功能,缓解呼吸困难症状,预防呼吸衰竭。     

A study on the role of noninvasive ventilation in mild-to-moderate acute respiratory distress syndrome

Aim:There is sparse data on the role of noninvasive ventilation (NIV) in acute respiratory distress syndrome (ARDS) from India. Herein, we report our experience with the use of NIV in mild to moderate ARDS.Results:A total of 41 subjects (27 women, mean age: 30.9 years) were included in the study. Tropical infections followed by abdominal sepsis were the most common causes of ARDS. The use of NIV was successful in 18 (44%) subjects, while 23 subjects required intubation. The median time to intubation was 3 h. Overall, 19 (46.3%) deaths were encountered, all in those requiring invasive ventilation. The mean duration of ventilation was significantly higher in the intubated patients (7.1 vs. 2.6 days, P = 0.004). Univariate analysis revealed a lack of improvement in PaO₂/FiO₂ at 1 h and high baseline Acute Physiology and Chronic Health Evaluation II (APACHE II) as predictors of NIV failure.Conclusions:Use of NIV in mild to moderate ARDS helped in avoiding intubation in about 44% of the subjects. A baseline APACHE II score of >17 and a PaO₂/FiO₂ ratio <150 at 1 h predicts NIV failure.     

A multicentered study on efficiency of noninvasive ventilation procedures(SAFE-NIV)

Background/aim To characterize the clinical course of noninvasive positive pressure ventilation (NIPPV) and high flow humidified nasal cannula ventilation (HFNC) procedures; perform risk analysis for ventilation failure.Material and methodsThis prospective, multi-centered, observational study was conducted in 352 PICU admissions (1 month-18 years) between 2016 and 2017. SPSS-22 was used to assess clinical data, define thresholds for ventilation parameters and perform risk analysis.Results Patient age, onset of disease, previous intubation and hypoxia influenced the choice of therapy mode: NIPPV was preferred in older children (p = 0.002) with longer intubation (p < 0.001), ARDS (p = 0.001), lower respiratory tract infections (p < 0.001), chronic respiratory disease, (p = 0.005), malignancy (p = 0.048) and immune deficiency (p = 0.026). The failure rate was 13.4%. sepsis, ARDS, prolonged intubation, and use of nasal masks were associated with NIV failure (p = 0.001, p < 0.001, p < 0.001, p = 0.025). The call of intubation or re-intubation was given due to respiratory failure in twenty-seven (57.5%), hemodynamic instability in eight (17%), bulbar dysfunction or aspiration in 5 (10.6%), neurological deterioration in 4 (8.5%) and developing ARDS in 3 (6.4%) children. A reduction of less than 10% in the respiration within an hour increased the odds of failure by 9.841 times (OR: 9.841, 95% CI: 2.0021–48.3742). FiO2 > 55% at 6th hours and PRISM-3 >8 were other failure predictors. Of the 9.9% complication rate, the most common complication was pressure ulcerations (4.8%) and mainly observed when using full-face masks (p = 0.047). Fifteen (4.3%) patients died of miscellaneous causes. Tracheostomy cannulation was performed on 16 children due to prolonged mechanical ventilation (8% in NIPPV, 2.6% in HFNC)ConclusionAbsence of reduction in the respiration rate within an hour, FiO2 requirement >55% at 6th hours and PRISM-3 score >8 predict NIV failure.     

Alternating ventilation in a rat model of increased abdominal pressure

During alternating ventilation (AV) one lung is inflating while the other is deflating. Considering the possible respiratory and hemodynamic advantages of AV, we investigated its effects during increased intra-abdominal pressure (IAP=10 mmHg). In Sprague-Dawley rats (n=6, 270-375g) the main bronchi were independently cannulated, and respiratory mechanics determined while animals underwent different ventilatory patterns: synchronic ventilation without increased IAP (SV-0), elevated IAP during SV (SV-10), and AV with elevated IAP (AV-10). Thirty-three other animals (SV-0, n=10; SV-10, n=11 and AV-10, n=12) were ventilated during 3h. Mean arterial pressure (MAP), and lung histology were assessed. Increased IAP resulted in significantly higher elastances (p<0.001), being AV-10 lower than SV-10 (p<0.020). SV-10 showed higher central venous pressure (p<0.003) than S-0; no change was observed in AV-10. Wet/dry lung weight ratio was lower in AV-10 than SV-10 (p=0.009). Application of AV reduced hemodynamic and lung impairments induced by increased IAP during SV.     

Correlation between central venous pressure and peripheral venous pressure with passive leg raise in patients on mechanical ventilation

Background:

Central venous pressure (CVP) assesses the volume status of patients. However, this technique is not without complications. We, therefore, measured peripheral venous pressure (PVP) to see whether it can replace CVP.

Aims:

To evaluate the correlation and agreement between CVP and PVP after passive leg raise (PLR) in critically ill patients on mechanical ventilation.

Setting and Design:

Prospective observational study in Intensive Care Unit.

Methods:

Fifty critically ill patients on mechanical ventilation were included in the study. CVP and PVP measurements were taken using a water column manometer. Measurements were taken in the supine position and subsequently after a PLR of 45°.

Statistical Analysis:

Pearson''s correlation and Bland–Altman''s analysis.

Results:

This study showed a fair correlation between CVP and PVP after a PLR of 45° (correlation coefficient, r = 0.479; P = 0.0004) when the CVP was <10 cmH₂O. However, the correlation was good when the CVP was >10 cmH₂O. Bland–Altman analysis showed 95% limits of agreement to be −2.912–9.472.

Conclusion:

PVP can replace CVP for guiding fluid therapy in critically ill patients.     

The role of non-invasive positive pressure ventilation in post-extubation respiratory failure: An evaluation using meta-analytic techniques

Background:

The use of non-invasive positive pressure ventilation (NIPPV) in post-extubation respiratory failure is not well-established. Meta-analytic techniques were used to assess the effects of prophylactic application of NIPPV (prior to the development of respiratory failure) and therapeutic application of NIPPV (subsequent to the development of respiratory failure).

Materials and Methods:

Randomized controlled trials (RCTs) from 1966 to May 2010 were identified using electronic databases. RCTs, which reported the use of NIPPV in post-extubation respiratory failure with defined assessable endpoints: reintubation, mortality and length of stay, were included.

Results:

Reintubation was the primary outcome, mortality and lengths of stay were the secondary outcomes. Risk ratios (RR) were calculated for discrete outcomes and weighted mean differences (WMD) for continuous measures. There were 13 trials with 1420 patients; 9 prophylactic with 861 patients and 4 therapeutic with 559 patients. In the prophylactic group, NIPPV was associated with lower rates of reintubation: RR 0.53 (95% confidence interval [CI], 0.28-0.98), P = 0.04. In the therapeutic group, NIPPV showed a null effect on reintubation: RR 0.79 (95% CI, 0.50-1.25), P = 0.31. The analysis on the secondary outcomes suggested significant reduction of hospital mortality with prophylactic application of NIPPV: RR 0.62 (95% CI 0.4-0.97), P = 0.03, with no effect on the other outcomes. Therapeutic application of NIPPV reduced intensive care unit length of stay: WMD −1.17 (95% CI −2.82 to −0.33), P = 0.006, but no effect on the other secondary outcomes.

Conclusions:

The results of this review suggested prophylactic NIPPV was beneficial with respect to reintubation and the therapeutic use of NIPPV showed a null effect.     

Multislice fractional ventilation imaging in large animals with hyperpolarized gas MRI

The noninvasive assessment of regional lung ventilation is of critical importance in the quantification of the severity of disease and evaluation of response to therapy in many pulmonary diseases. This work presents, for the first time, the implementation of a hyperpolarized (HP) gas MRI technique to measure whole-lung regional fractional ventilation (r) in Yorkshire pigs (n = 5) through the use of a gas mixing and delivery device in the supine position. The proposed technique utilizes a series of back-to-back HP gas breaths with images acquired during short end-inspiratory breath-holds. In order to decouple the radiofrequency pulse decay effect from the ventilatory signal build-up in the airways, the regional distribution of the flip angle (α) was estimated in the imaged slices by acquiring a series of back-to-back images with no interscan time delay during a breath-hold at the tail end of the ventilation sequence. Analysis was performed to assess the sensitivity of the multislice ventilation model to noise, oxygen and the number of flip angle images. The optimal α value was determined on the basis of the minimization of the error in r estimation: α(opt) = 5-6o for the set of acquisition parameters in pigs. The mean r values for the group of pigs were 0.27 ± 0.09, 0.35 ± 0.06 and 0.40 ± 0.04 for the ventral, middle and dorsal slices, respectively (excluding conductive airways r 0.9). A positive gravitational (ventral-dorsal) ventilation gradient effect was present in all animals. The trachea and major conductive airways showed a uniform near-unity r value, with progressively smaller values corresponding to smaller diameter airways, and ultimately leading to lung parenchyma. The results demonstrate the feasibility of the measurement of the fractional ventilation in large species, and provide a platform to address the technical challenges associated with long breathing time scales through the optimization of acquisition parameters in species with a pulmonary physiology very similar to that of humans.     

Adaptive support ventilation: State of the art review

Mechanical ventilation is one of the most commonly applied interventions in intensive care units. Despite its life-saving role, it can be a risky procedure for the patient if not applied appropriately. To decrease risks, new ventilator modes continue to be developed in an attempt to improve patient outcomes. Advances in ventilator modes include closed-loop systems that facilitate ventilator manipulation of variables based on measured respiratory parameters. Adaptive support ventilation (ASV) is a positive pressure mode of mechanical ventilation that is closed-loop controlled, and automatically adjust based on the patient''s requirements. In order to deliver safe and appropriate patient care, clinicians need to achieve a thorough understanding of this mode, including its effects on underlying respiratory mechanics. This article will discuss ASV while emphasizing appropriate ventilator settings, their advantages and disadvantages, their particular effects on oxygenation and ventilation, and the monitoring priorities for clinicians.     

应用T型管和压力支持进行程序化拔除气管插管比较

目的在程序化脱离呼吸机拔出气管插管的过程中,分别采用T型管和压力支持(PSV)进行30 min的自主呼吸试验(SBT),比较两者的临床效果。方法55例患者随机分为T型管组(n=27)和PSV组(n=28)。程序化拔除气管插管分两个步骤进行,即检测阶段和SBT阶段。当患者完成SBT阶段,而且呼吸频率≤35次/min,PaO2≥9.33 kPa(70mmHg),即可拔出气管插管。结果两组患者均成功进行了SBT、拔出气管插管。T型管组在30 min时完成SBT者为85.2%(23/27),PSV组为85.7%(24/28),两组各有1例患者在拔管后48 h内重复进行气管插管。两组患者平均机械通气时间分别为(38.11±51.20)h(T型管组)(、34.58±35.04)h(PSV组);拔除气管插管前血清白蛋白、血红蛋白含量没有差别,但均低于正常值。结论应用T型管和PSV进行30 min的SBT,临床结果相似。在该研究中,血中低水平的血清白蛋白、血红蛋白未对拔除气管插管产生负面影响。