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     

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.     

超声诊断方案对重症机械通气患者撤机效果及纵膈移位的影响

目的:分析超声诊断方案对重症机械通气患者撤机效果及纵膈移位情况的影响。方法:选取机械通气时间>48 h并行自主呼吸试验的重症患者96例,超声检测记录SBT不同时间节点的浅快呼吸指数（RSBI）、纵膈肌增厚率（DTF）、膈肌收缩速度和最大右侧膈肌移位（DE）,根据撤机结果将患者分为撤机成功组和撤机失败组,比较两组患者上述指标差异,并利用受试者工作曲线（ROC）评价SBT 30 min时各指标单独及联合对撤机成功的预测价值。结果:撤机成功者62例,撤机失败者34例,撤机失败率为35.42%;SBT 30 min时,撤机成功组患者RSBI值、膈肌收缩速度低于撤机失败组,DTF、DE值高于撤机失败组,差异均具有统计学意义（P<0.05）;Logistic回归分析发现,RSBI、膈肌收缩速度的升高和DTF、DE的降低是撤机失败的独立危险因素（P<0.05）;ROC结果显示,RSBI、DTF、膈肌收缩速度、DE预测撤机失败的Cutoff值分别为74.19次/min·L-1、35.37%、1.74 cm/s、1.61 mm;各指标单独预测撤机失败的AUC分别为0.798、0.809、0.774、0.870,而RSBI+DTF+膈肌收缩速度+DE联合预测的AUC为0.951,显著高于各项指标单独预测（P<0.05）。结论:超声诊断能够通过RSBI、DTF、膈肌收缩速度、DE监测膈肌移位情况,还能很好地预测重症机械通气患者撤机结果,联合诊断效果更佳。     

有创机械通气的危重症患者支气管肺泡灌洗临床观察

目的观察经纤维支气管镜支气管肺泡灌洗和经吸痰管注水后吸出方式灌洗的临床效果。方法93例行机械通气的危重症患者,其中男性59例,女性34例,年龄18～92岁;随机分为两组。进行经纤维支气管镜支气管肺泡灌洗（A组）和经吸痰管注水后吸出方式灌洗（B组）。观察并比较两组对象灌洗前后的气道峰压（PIP）、内源性PEEP（PEEPi）、动脉氧分压（PaO2）、动脉二氧化碳分压（PaCO2）及有创机械通气时间、重症监护病房（ICU）入住时间和病死率。结果两组的PIP和PEEPi较灌洗前均有明显下降;两组组间APIP、APEEPi比较,A组大于B组;两组的PaCO2较灌洗前有明显下降,两组的PaO2均较灌洗前有明显升高;A组分别在PaCO2降低和PaO2升高的程度上优于B组;A组有创机械通气时间和ICU入住时间均较B组明显缩短;以上比较差异均有统计学意义。但两组病死率差异无统计学意义。结论对有创机械通气的危重症患者进行经纤维支气管镜支气管肺泡灌洗或经吸痰管注水后吸出方式灌洗,均可以改善呼吸力学参数和血气参数。经纤维支气管镜支气管肺泡灌洗效果优于经吸痰管注水后吸出方式灌洗,值得广泛开展。     

Interpretation of arterial blood gas

Disorders of acid–base balance can lead to severe complications in many disease states, and occasionally the abnormality may be so severe as to become a life-threatening risk factor. The process of analysis and monitoring of arterial blood gas (ABG) is an essential part of diagnosing and managing the oxygenation status and acid–base balance of the high-risk patients, as well as in the care of critically ill patients in the Intensive Care Unit. Since both areas manifest sudden and life-threatening changes in all the systems concerned, a thorough understanding of acid–base balance is mandatory for any physician, and the anesthesiologist is no exception. However, the understanding of ABGs and their interpretation can sometimes be very confusing and also an arduous task. Many methods do exist in literature to guide the interpretation of the ABGs. The discussion in this article does not include all those methods, such as analysis of base excess or Stewart’s strong ion difference, but a logical and systematic approach is presented to enable us to make a much easier interpretation through them. The proper application of the concepts of acid–base balance will help the healthcare provider not only to follow the progress of a patient, but also to evaluate the effectiveness of care being provided.     

Effects of deep sedation on sleep in critically ill medical patients on mechanical ventilation

Atypical EEG patterns not consistent with standard sleep staging criteria have been observed in medical intensive care unit (ICU) patients. Our aim was to examine the relationship between sleep architecture and sedation in critically ill mechanically ventilated patients pre‐ and post‐extubation. We performed a prospective observational repeated measures study where 50 mechanically ventilated patients with 31 paired analyses were examined at an academic medical centre. The sleep efficiency was 58.3 ± 25.4% for intubated patients and 45.6 ± 25.4% for extubated patients (p = .02). Intubated patients spent 76.33 ± 3.34% of time in non‐rapid eye movement (NREM) sleep compared to 64.66 ± 4.06% of time for extubated patients (p = .02). REM sleep constituted 1.36 ± 0.67% of total sleep time in intubated patients and 2.06 ± 1.09% in extubated patients (p = .58). Relative sleep atypia was higher in intubated patients compared to extubated patients (3.38 ± 0.87 versus 2.79 ± 0.42; p < .001). Eleven patients were sedated with propofol only, 18 patients with fentanyl only, 11 patients with fentanyl and propofol, and 10 patients had no sedation. The mean sleep times on “propofol”, “fentanyl”, “propofol and fentanyl,” and “no sedation” were 6.54 ± 0.64, 4.88 ± 0.75, 6.20 ± 0.75 and 4.02 ± 0.62 hr, respectively. The sigma/alpha values for patients on “propofol”, “fentanyl”, “propofol and fentanyl” and “no sedation” were 0.69 ± 0.04, 0.54 ± 0.01, 0.62 ± 0.02 and 0.57 ± 0.02, respectively. Sedated patients on mechanical ventilation had higher sleep efficiency and more atypia compared to the same patients following extubation. Propofol was associated with higher sleep duration and less disrupted sleep architecture compared to fentanyl, propofol and fentanyl, or no sedation.     

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。     

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。     

Risk factors for mortality of critically ill patients with COVID-19 receiving invasive ventilation

Rationale: Early invasive ventilation may improve outcomes for critically ill patients with COVID-19. The objective of this study is to explore risk factors for 28-day mortality of COVID-19 patients receiving invasive ventilation.Methods: 74 consecutive adult invasively ventilated COVID-19 patients were included in this retrospective study. The demographic and clinical data were compared between survivors and non-survivors, and Cox regression analysis was used to explore risk factors for 28-day mortality. The primary outcome was 28-day mortality after initiation of invasive ventilation. Secondary outcome was the time from admission to intubation.Results: Of 74 patients with COVID-19, the median age was 68.0 years, 53 (71.6%) were male, 47 (63.5%) had comorbidities with hypertension, and diabetes commonly presented. The most frequent symptoms were fever and dyspnea. The median time from hospital admission to intubation was similar in survivors and non-survivors (6.5 days vs. 5.0 days). The 28-day mortality was 81.1%. High Sequential Organ Failure Assessment (SOFA) score (hazard ratio [HR], 1.54; 95% confidence interval [CI], 1.23-1.92; p < 0.001) and longer time from hospital admission to intubation (HR, 2.41; 95% CI, 1.15-5.07; p = 0.020) were associated with 28-day mortality in invasively ventilated COVID-19 patients.Conclusions: The mortality of invasively ventilated COVID-19 patients was particularly striking. Patients with high SOFA score and receiving delayed invasive ventilation were at high risk of mortality.     

A comparison of blood gases and acid-base measurements in arterial,arterialized venous,and venous blood during short-term maximal exercise

Summary The purpose of this study was to determine the relationship between blood gases and acid-base measurements in arterial, arterialized venous, and venous blood measured simultaneously during short-term maximal exercise. Ten well-trained male cyclists performed a graded maximal exercise test on a cycle ergometer to determine the power output corresponding to their peak oxygen consumption (test I), and a short-term maximal test on a cycle ergometer at peak power output (test 11). During test 11 arterial, arterialized venous and venous blood were sampled simultaneously for determination of partial pressures of oxygen and carbon dioxide, pH, bicarbonate (HCO₃ ^–), base excess (BE), and lactate (La). Samples were taken at rest, the end of 1 min of exercise (1 ME), at the end of exercise (EE), and at 2 min of recovery (REC). During test II, subjects maintained a peak power output of 370.6 (62.1) W [mean (SD)] for 4.5, SD 1.6 min. Except at rest venous and arterialized venous measurements tended to be the same at all sampling intervals, but differed significantly from measurements in arterial blood (P<0.05). BE was the only variable that rendered consistently significant correlations between arterial and arterialized venous blood at each sampling interval. The pooled correlation coefficient between arterial and arterialized venous BE was r=0.83 [regression equation: BE_a=(0.84 BE_av)–0.51]. Arterial La was significantly higher than venous La at 1 ME (2.8, 0.7 vs 0.8, 0.3mmol · 1^–1) and higher than both venous and arterialized venous La at EE. At EE La concentration was 9.2, SD 2.0, 4.6, SD 0.4, and 5.1, SD 0.1 mmol · 1^–1 in arterial, venous, and arterialized venous blood respectively. It is concluded that except for base excess, blood gases and acid base measurements in venous and arterialized venous blood do not accurately reflect values found in arterial blood during short-term maximal exercise. We suggest that these differences may be due in part to clearance by inactive muscle near the sampling site or vasoconstriction at the inactive sampling site.     

Prediction of outcome and prognosis of patients on mechanical ventilation using body mass index, SOFA score, C-Reactive protein, and serum albumin

Context:

Body mass index (BMI), serum albumin, and C-reactive protein (CRP) appear to be major determinants of hospitalization.

Aim:

To determine the predictive ability of BMI, Sequential Organ Failure Assessment (SOFA score), serum albumin, and CRP to assess the duration and outcome of mechanical ventilation (MV).

Materials and Methods:

Thirty patients aged >18 years who required mechanical ventilation (MV) were enrolled for the study. They were divided into two groups; patients who improved (Group 1), patients who expired (Group 2). Group 1 was further divided into two groups: patients on MV for <5 days (Group A), and patients on MV for >5days (Group B). BMI and SOFA score were calculated, and serum albumin and CRP were estimated.

Results and Discussion:

Out of the 30 patients, 18 patients successfully improved after MV (Group 1) and 12 patients expired (Group 2). Among the 18 patients in group 1, ten patients improved within 5 days (Group A) and 8 patients after 5 days (Group B). SOFA score and CRP were significantly increased (P value 0.0003 and 0.0001, respectively) in group 2 when compared to group 1. CRP >24.2 mg/L or SOFA score >7 at the start of MV increases the probability of mortality by factor 13.08 or 3.92, respectively The above parameters did not show any statistical difference when group A was compared to group B.

Conclusion:

Simple, economic and easily accessible markers like CRP and assessment tools of critically ill patients with SOFA score are important determinants of possible outcomes of a patient from MV.     

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.     

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。     

ABCDE镇静镇痛策略对重症机械通气患者呼吸力学的影响

目的:探讨ABCDE镇痛镇静策略对重症机械通气(mechanical ventilation,MV)患者呼吸力学的影响.方法:根据转入ICU时间顺序对重症MV患者进行分组,其中对照组采用常规镇痛镇静方案,观察组采用ABCDE镇痛镇静干预策略,收集并比较两组在干预前(T0)和干预后第I(T1),3(T2),5(T3),7(T4)天的呼吸力学参数变化情况,以及患者治疗预后情况.结果:两组在不同时间点的呼吸力学参数比较,观察组在T2～T4的气道峰压(Ppeak)、平台压(Pplat)、动态顺应性(Cdny)及潮气量(tidal volume,VT)均较T0明显改善,且改善效果明显优于同期对照组(P＜0.05);重复测量方差分析结果显示其组内效应、时间效应及交互效应差异均有统计学意义(p＜0.05).在治疗预后各指标比较方面,观察组的MV时间、ICU停留天数明显缩短,28 d生存率明显高于对照组(p＜0.05).结论:ABCDE镇痛镇静策略是一种安全有效的干预策略,可有效降低重症MV患者的气道压力,增加VT和提升肺部的动态顺应性,对于促进治疗预后具有积极的推动作用.     

小潮气量和传统潮气量机械通气治疗小儿重症肺炎的疗效对比分析

目的：对比分析小潮气量和传统潮气量机械通气治疗小儿重症肺炎的疗效。方法：对2013年6月至2015年6月在我院进行接治的100例小儿重症肺炎进行研究,将患儿随机分为对照组和观察组,各50例,对照组的患儿采用传统潮气量,潮气量为10~12 mL/kg;观察组的患儿采用小潮气量,潮气量为6~8 mL/kg,对治疗过程中两组患儿临床参数的变化进行对比分析。结果：观察组患儿的机械通气时间明显多于对照组(t=11.0770,P=0.0000),观察组患儿的病死率明显高于对照组(χ2=5.4825,P=0.0192),治疗过程中,两组患儿的平均气道压(Paw)、吸入氧浓度(fraction of inspiration O2,FiO2)、高呼吸末正压(positive end expiratory pressure,PEEP)、吸气峰压(peak inflating pressure,PIP)等临床各指标的变化无明显差异(P>0.05),观察组与对照组存活患儿的反复呼吸道感染发生率无明显差异(χ2=0.0624,P=0.8028)。结论：对重症肺炎患儿进行机械通气时,传统潮气量的治疗效果优于小潮气量。     

机械通气患者靶控输注舒芬太尼和芬太尼的血流动力学比较研究

目的初步探讨靶控输注舒芬太尼和芬太尼在机械通气患者中效果比较。方法收集2012年1月到2013年11月佛山市第一人民医院重症医学科40例血压正常机械通气患者进行随机对照临床试验研究。随机分为舒芬太尼组和芬太尼组,每组各20例,40例患者均给予2.0 ng/mL哚达唑仑镇静后,进行气管插管和后行机械通气,舒芬太尼组靶向输注方式给予0.2 ng/mL舒芬太尼,芬太尼组靶向输注方式给予0.2 ng/mL芬太尼;比较研究机械通气后患者的血压和气管插管后心率在5个不同时间点,即第1小时（T1）、第2小时（T2）、第3小时（T3）、第4小时（T4）和第5小时（T5）的变化。结果受试者不同时间点的收缩压、舒张压、平均动脉压和心率都低于正常值,差异具有统计学意义（P〈0.05）。舒芬太尼组和芬太尼组比较,气管插管后T2、T3、T4的血压与T1比较差异有统计学意义（χ^2=9.62,P〈0.05）,RI〉1,说明芬太尼对于患者心率的副作用较舒芬太尼小。舒芬太尼组患者在机械通气后（T0）,T1,T2,T3,T4,T5的收缩压,舒张压和平均动脉压与芬太尼组比较差异无统计学意义（χ2=15.35,P〉0.05）。结论芬太尼和舒芬太尼两者都可以有效的阻止机械通气患者的血压和心率升高,但是需要考虑低血压和心动过缓的副作用。     

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.     

ICU科内ABL80 FLEX血气分析仪使用技巧

血气分析技术一直在临床手术、抢救与监护过程中发挥着至关重要的作用,但如使用不当会导致仪器设备发生故障,减少仪器使用寿命,进而影响患者的救治。本文总结了多年在ICU 工作的科内血气分析仪使用的经验,期望能对初入ICU的同行有所帮助。