序贯双水平气道正压通气在COPD有创机械通气撤机中的作用

目的评价慢性阻塞性肺病（chronic obstructive pulmonary disease,COPD）伴有急性高碳酸性呼吸衰竭气管插管机械通气患者,以“肺部感染控制窗”的出现为切换点改用序贯面罩双水平气道正压通气（bilevel positive airwaypressure,BiPAP）进行撤机的结果。方法序贯治疗组14例,COPD伴有急性高碳酸性呼吸衰竭气管插管机械通气患者,当临床出现＂肺部感染控制窗＂即拔除气管插管,改用序贯BiPAP面罩无创通气;传统治疗组（对照组）14例,继续气管插管机械通气,以SIMV＋PSV模式撤机。记录并比较两组患者出窗的时间、撤机前后的动脉血气水平、有创机械通气时间、总机械通气（有创通气＋无创通气）时间、呼吸重症监护室（respiratory intensive care unit,RICU）住院时间、总住院时间、再插管率、气管切开的比例、呼吸机相关性肺炎（ventilator associated pneumonia,VAP）的发生率、撤机成功率、住院死亡率以及药费和总费用。结果序贯组与传统组相比较,出窗的时间无明显差异,分别为（5.5±2.4）d和（5.7±3.3）d,P〉0.05,2组的气体交换相似。序贯组撤机成功率提高、VAP发生率降低、再插管率降低、气管切开率下降、有创机械通气时间减少、总机械通气时间减少I、CU入住时间缩短、总住院时间缩短、住院死亡率降低、药费和总费用降低。结论COPD伴有急性高碳酸性呼吸衰竭气管插管机械通气患者,在肺部感染控制窗出现后序贯BiPAP面罩无创通气进行撤机的策略,明显降低了再插管、气管切开和VAP发生的,缩短了机械通气和住院的时间,提高了撤机的成功率,降低了住院死亡率,节约了医疗费用,是一种安全、经济、有效的治疗策略。     

Impaired growth of small intestinal epithelium by adrenalectomy in weaning rats

Functional maturation of the small intestine occurs during the weaning period in rats. It is known that this development is facilitated by glucocorticoid. However, the effect of glucocorticoid on morphological development of small intestine has yet to be clarified. The present study evaluated the morphological development and cell proliferation of the small intestine in adrenalectomized (ADX) rat pups. To further understand the mechanism of glucocorticoid effects on intestinal development, we examined the localization of the glucocorticoid receptor in the small intestine. Microscopic analysis showed that growth of villi and crypts is age-dependent, and is significantly attenuated in ADX rats compared with sham-operated rats. BrdU-positive cells, i.e. proliferating cells, were primarily observed in crypt compartments and rapidly increased in number during the early weaning period. The increase in BrdU-positive cells could be attenuated by adrenalectomy. The morphological development of small intestine may be associated with increased proliferation of epithelial cells. On the other hand, glucocorticoid receptors were found in epithelial cells of the mid- and lower villi and not in crypts where BrdU-positive cells were localized. These results indicate that the growth of small intestine is attenuated by adrenalectomy, and that glucocorticoid indirectly acts on proliferation of epithelial cells during the weaning period.     

Prediction of prolonged mechanical ventilation in patients in the intensive care unit A cohort study

Introduction:

There are no established guidelines for selecting patients for early tracheostomy. The aim was to determine the factors that could predict the possibility of intubation longer than 7 days in critically ill adult patients.

Methods:

This is cohort study made at a general intensive care unit. Patients who required at least 48 hours of mechanical ventilation were included. Data on the clinical and physiologic features were collected for every intubated patient on the third day. Uni- and multivariate statistical analyses were conducted to determine the variables associated with extubation.

Results:

163 (62%) were male, and the median age was 59±17 years. Almost one-third (36%) of patients required mechanical ventilation longer than 7 days. The variables strongly associated with prolonged mechanical ventilation were: age (HR 0.97 (95% CI 0.96-0.99); diagnosis of surgical emergency in a patient with a medical condition (HR 3.68 (95% CI 1.62-8.35), diagnosis of surgical condition-non emergency (HR 8.17 (95% CI 2.12-31.3); diagnosis of non-surgical-medical condition (HR 5.26 (95% CI 1.85-14.9); APACHE II (HR 0.91 (95% CI 0.85-0.97) and SAPS II score (HR 1.04 (95% CI 1.00-1.09) The area under ROC curve used for prediction was 0.52. 16% of patients were extubated after day 8 of intubation.

Conclusions:

It was not possible to predict early extubation in critically ill adult patients with invasive mechanical ventilation with common clinical scales used at the ICU. However, the probability of successfully weaning patients from mechanical ventilation without a tracheostomy is low after the eighth day of intubation.     

A knowledge-based system for assisted ventilation of patients in intensive care units

The procedure for weaning a patient with respiratory insufficiency from mechanical ventilation may be complex and requires expertise obtained by long clinical practice. We designed a knowledge-based system for the management of patients receiving respiratory support and implemented a weaning procedure. The system is intended for patients whose spontaneous respiratory activity is assisted by a Hamilton Veolar ventilator delivering a positive pressure plateau during inspiration (Pressure Support Ventilation mode). Our closed-loop real-time system running on a Personal Computer continuously adapts the assistance provided by the ventilator to the patient's evolution, and indicates when the patient can be withdrawn from the ventilator. Three parameters are used to appreciate the respiratory comfort of the patient: breathing frequency, which we consider the most informative index, tidal volume and end-tidal CO₂ pressure. A preliminary study of 19 patients was performed to evaluate the ability of our system to adapt the assistance to the patient's needs, with the main objective of facilitating weaning by gradually lowering the level of assistance. In 10 of these patients, considered as good candidates for weaning on the strength of objective criteria, the system maintained the breathing pattern in a zone of comfort for 95% of the period of assisted ventilation and stated that they were weanable. This was consistent with the clinical evolution of all 10 patients. These results show that such a system can provide effective management for mechanically ventilated patients.     

慢性阻塞性肺疾病患者程序化撤机策略的研究

目的探讨慢性阻塞性肺疾病（COPD）程序化撤机策略。方法采用前瞻组性对照研究方法。将COPD机械通气患者分为两组,程序化组采用程序化撤机策略,患者先通过浅快呼吸指数筛选,随即进行自主呼吸试验（SBT）,通过SBT患者即可拔除气管插管。非程序化组患者依靠医生的主观判断与临床经验来决定撤离呼吸机的时机。结果程序化组与非程序化组机械通气时间分别为（8．01±7．22）d和（10．74±5．58）d,ICU住院时间分别为（8．86±6．92）d和（12±6．10）d,程序化组明显低于非程序化组（P〈0．05）。程序化组撤机成功率为76．31％,非程序化组为47．36％,差异有统计学意义（P〈0．05）。结论应用程序化撤机策略及SBT方法可以减少COPD患者机械通气时间及住ICU时间,提高撤机的成功率。     

机械通气患者早期肺康复治疗的临床观察

目的:将早期肺康复治疗应用于机械通气72h内的重症患者,观察其对呼吸机的撤离、呼吸机相关肺炎(ventilator associated pneumonia,VAP)发生率、肺部感染严重程度及重症监护病房(intensive care unit,ICU)住院时间的影响。方法:本研究是一项单中心、观察性、评估者盲法实验,筛选符合研究条件的82例患者,分为试验组和对照组,每组各41例,两组患者均给予ICU常规治疗,试验组患者在常规治疗基础上进行早期肺康复治疗。比较两组患者撤机成功率、VAP发生率、急性生理与慢性健康状况评分Ⅱ(acute physiology and chronic health evaluation,APACHEⅡ)、临床肺部感染评分(clinical pulmonary infection score,CPIS)、机械通气时间、ICU住院时间。结果:两组患者的年龄、性别、诊断及治疗前的APACHEⅡ评分、CPIS评分差异均无显著性意义(P0.05)。试验组患者的撤机成功率(87.80%)较对照组显著提高,而VAP发生率(14.63%)明显低于对照组,机械通气时间(6.90±4.61D)和ICU住院时间(12.34±7.23D)较对照组显著缩短(P0.05),治疗后试验组CPIS评分明显低于对照组(P0.05),差异有显著性意义(P0.05)。结论:早期肺康复治疗可以提高撤机成功率,降低VAP发生率,减轻肺部感染,缩短机械通气持续时间和ICU住院时间。     

血必净注射液用于机械通气患者疗效观察

目的:评价血必净注射液对机械通气患者的治疗效果。方法:将40例机械通气患者按随机原则分为对照组和治疗组,每组20例。对照组给予机械通气、抗生素、对症及营养支持治疗;治疗组在对照组治疗的基础上加用血必净注射液50ml静脉滴注,12h1次,连用7d。比较两组患者治疗前和治疗后5d的血白细胞计数(WBC)、C-反应蛋白(CRP)、气道压力、动脉血气以及成功撤机率、重症加强治疗病房(ICU)病死率。结果:两组患者的年龄和急性生理学与慢性健康状况评分系统(APACHE)差异均无显著性(P均>0.05),有可比性。治疗前两组患者的气道压力、动脉血气、WBC、CRP比较差异均无显著性(P均>0.05);治疗后5d治疗组患者的气道压力、动脉血气、CRP改善程度均显著优于对照组(P均<0.05),撤机成功率显著高于对照组(80%比50%,P<0.05),ICU病死率显著低于对照组(20%比50%,P<0.05)。结论:血必净注射液有利于机械通气患者拔管撤机,能降低机械通气患者的ICU病死率。     

慢性阻塞性肺疾病呼吸衰竭撤机中比例压力支持通气的调节方法

目的　探讨比例压力支持模式时比例调节法与目标调节法对慢性阻塞性肺疾病慢性呼吸衰竭急性加重患者机械通气参数调节的意义。方法　选择慢性阻塞性肺疾病慢性呼吸衰竭急性加重患者 75例 ,随机分为两组。采用脱逸法测定阻力和弹性回缩力 ,采用比例调节法和目标调节法分别调节呼吸机设定的流速辅助和容量辅助参数 ,以达到撤机目的。结果　两组患者测定的阻力、弹性回缩力 ,撤机时的流速辅助和容量辅助参数 ,通气时间和撤机成功率均无显著性差异。结论　脱逸法测定阻力和弹性回缩力操作简单。目标调节法能达到与比例调节法相同的调节目的和撤机成功率 ,但需要丰富的临床经验及加强临床监护     

心脏大血管术后呼吸机脱机困难患者的营养支持治疗

目的总结心脏大血管手术后呼吸机支持治疗患者营养支持的经验。方法回顾性分析本科近4年来29例呼吸机支持治疗≥72 h患者,采用肠外逐渐向肠内营养过渡,分阶段由低热卡逐步提高热卡支持治疗的治疗方案。结果 29例患者中7名患者死亡,其中3例死于严重感染,1例死于枕骨大孔疝,1例死于肾衰竭,2例死于术后低心排。无患者死于营养支持不当并发症。22例患者顺利脱离呼吸机后自主进食,并治愈出院。其中3例患者高血糖,调整胰岛素后即好转;7例患者出现鼻饲后腹泻,对症处理后好转;无患者出现高脂血症。结论心脏大血管外科手术后不能顺利脱机而不能正常进食的患者应采用肠外逐渐向肠内营养过渡,分阶段由低热卡逐步提高热卡支持治疗。     

Tracheostomy timing and the duration of weaning in patients with acute respiratory failure

Introduction

The effect of various airway management strategies, such as the timing of tracheostomy, on liberation from mechanical ventilation (MV) is uncertain. We tested the hypothesis that tracheostomy, when performed prior to active weaning, does not influence the duration of weaning or of MV in comparison with a more selective use of tracheostomy.

Patients and methods

In this observational prospective cohort study, surgical patients requiring ≥ 72 hours of MV were followed prospectively. Patients undergoing tracheostomy prior to any active weaning attempts (early tracheostomy [ET]) were compared with patients in whom initial weaning attempts were made with the endotracheal tube in place (selective tracheostomy [ST]).

Results

We compared the duration of weaning, the total duration of MV and the frequency of fatigue and pneumonia. Seventy-four patients met inclusion criteria. Twenty-one patients in the ET group were compared with 53 patients in the ST group (47% of whom ultimately underwent tracheostomy). The median duration of weaning was shorter (3 days versus 6 days, P = 0.05) in patients in the ET group than in the ST group, but the duration of MV was not (median [interquartile range], 11 days [9–26 days] in the ET group versus 13 days [8–21 days] in the ST group). The frequencies of fatigue and pneumonia were lower in the ET group patients.

Discussion

Determining the ideal timing of tracheostomy in critically ill patients has been difficult and often subjective. To standardize this process, it is important to identify objective criteria to identify patients most likely to benefit from the procedure. Our data suggest that in surgical patients with resolving respiratory failure, a patient who meets typical criteria for a trial of spontaneous breathing but is not successfully extubated within 24 hours may benefit from a tracheostomy. Our data provide a framework for the conduct of a clinical trial in which tracheostomy timing can be assessed for its impact on the duration of weaning.

Conclusion

Tracheostomy prior to active weaning may hasten liberation from ventilation and reduce complications. However, this does not reduce the overall duration of MV.