撤机前浅快呼吸指数作为呼吸机撤离指标的临床研究

目的 :研究RVR对机械通气患者撤机的预测价值。方法 :回顾分析过去两年需机械通气治疗的患者104例 ,按照引起呼衰的不同病因分为COPD、ARDS、术后及其他4组。比较常规撤机指标 :RR、VT 、VE 及RVR对机械通气患者撤机的预测价值 ,所有指标都是在BIPAP及CPAP方式下测定的。结果 :除术后组20例全部撤机成功外 ,其他3组中撤机成功组与撤机失败组的RVR分别为 ,COPD组[(58±23)次 / (min·L)vs(80±25)次 /(min·L) ,P<0 05] ,ARDS组[(64±19)次 / (min·L)vs(84±16)次 / (min·L) ,P<0 05]、其他组[(60±21)次 / (min·L)vs(88±21)次 / (min·L) ,P<0 05]。按照机械通气时间的不同分为3组 :≤7天、>7天及撤机失败组 ,RVR分别为 (56±20)次 / (min·L)、(67±17)次 / (min·L)和 (78±23)次 / (min·L) ,P<0 05。以RVR≤105次 / (min·L)为标准 ,预测撤机成功的诊断正确率、灵敏度和特异度分别为82 %、92 %和37 %。结论 :RVR对预测撤机的后果好于常规撤机指标 ,如RR、VT、VE,对撤机有一定的指导意义     

Computer-assisted capnogram analysis

Characteristic abnormal carbon dioxide waveforms from patients with mechanically ventilated lungs are observed when, for example, valves are incompetent, the airway is obstructed, the breathing circuit becomes disconnected, or a patient overrides mechanical ventilation with spontaneous breaths. Automated observation of the carbon dioxide waveform provides a uniform, concise, and consistent interpretation of the capnogram. This article describes a computer algorithm for analyzing and classifying capnograms as normal or as belonging to one of the categories above. The algorithm also generates a diagnostic message when the capnogram deviates from a learned norm for at least three consecutive waveforms (and thus reduces the influence of artifacts). Clinical experience shows reliable waveform recognition by the algorithm.Supported in part by a grant from Datascope Corporation.The authors thank David A. Paulus, MD, and Jeffrey M. Feldman, MD, for their assistance and advice.     

体外膜肺对犬肺泡Ⅱ型上皮细胞系统超微结构的影响

目的：观察体外膜肺(ECMO)早期肺泡Ⅱ型上皮细胞(ATⅡ)及肺表面活性物质(PS)系统超微结构改变，探讨ECMO过程中ATⅡ功能变化，不断改良ECMO技术。方法：应用电子显微镜观察体外膜肺犬ATⅡ及PS系统超微结构。结果：ECMO组均可见PS层丧失连续、均匀绒状结构，脱落人肺泡腔或聚集成块现象或散落于肺泡腔内；可见ATⅡ板层小体减少、空泡形成，核变性、崩解；基底膜水肿、裸露，甚至断裂，炎性细胞渗出到肺泡腔。与对照组比较有显著差异，提示现有的ECMO治疗6h可引起肺泡Ⅱ型上皮细胞系统超微结构的改变。结论：现有的ECMO技术还有待改良。     

呼吸机的性能评价

呼吸机的性能主要体现在它的触发和流量稳定性上，不同的机型存在着差异。     

Single operator cardiopulmonary resuscitation in ambulances

Cardiopulmonary resuscitation en route to hospital is performed by a single-handed operator in many British ambulances. In this study, three emergency ventilation devices, and mouth-to-mouth breathing, were compared for effectiveness in unintubated patients. Seventeen paramedics used each method on a Laerdal manikin in a randomised order, under identical conditions. Three experienced cardiopulmonary resuscitation instructors repeated the tests in a moving ambulance. There were significant differences in minute volume (p less than 0.01) and number of effective chest compressions (p less than 0.05); mouth-to-mouth breathing produced the best overall results and the simplest device was a close second. The value of automatic ventilators for single-operator cardiopulmonary resuscitation in unintubated patients is questioned.     

品管圈在降低呼吸机报警频次中的应用

目的：探讨品管圈在降低呼吸机报警频次中的应用效果。方法严格按照品管圈活动的各个步骤,针对引起呼吸机报警频次较高的原因,提出相应的对策并严格实施。结果实施品管圈前后呼吸机的报警主要类型均为气道压高、呼吸频率高、吸气潮气量超限,报警主要原因均为呼吸道分泌物过多、患者不舒适、呼吸系统泄露,在实施品管圈活动前后的呼吸机报警频次之间,存在显著统计学差异（ P＜0.01）。结论品管圈活动可以降低呼吸机的报警频次,但目前尚无法显著改善引起呼吸机报警的原因。     

Development and validation of an algorithm for identifying prolonged mechanical ventilation in administrative data

Patients requiring prolonged mechanical ventilation (PMV) are a subset of critically ill patients with high resource utilization and poor long-term outcomes. We sought to develop an algorithm for identifying patients receiving PMV, defined as either 14 or 21 days of mechanical ventilation, in administrative and claims data. The algorithm was derived in mechanically ventilated patients at an academic medical center (n = 1,500) and validated in patients with community-acquired pneumonia in a multi-center clinical registry (n = 20,370), with further evaluation in the Pennsylvania discharge database (n = 62,383). The final algorithm combined the International Classification of Diseases codes for mechanical ventilation, diagnosis related groups for ventilation and tracheostomy, and intensive care unit length of stay. In the derivation dataset the algorithm was highly sensitive (14 days = 92.4%; 21 days = 97.6%) and specific (14 days = 91.6%, 21 days = 92.1%). The definition continued to perform well in the validation dataset (14 days: sensitivity = 87.6%, specificity = 88.5%). In both the derivation and validation datasets the negative predictive value was over 95% and positive predictive values ranged from 60% to 70%. In state discharge data the algorithm identified a cohort of patients with high costs and frequent discharge to skilled care facilities. Administrative data can be used to accurately identify populations of patients receiving PMV.     

Portable Emergency Ventilators. A Lung Model Study

The ventilatory performance of four portable emergency ventilators (Logic 07, Motivus Oxylog and Pneupac II) was tested on a lung model. The model consisted of one common (tracheal) tube, two separate (bronchial) tubes in which different obstructions could be applied, and two glass jars filled with water to suitable compliances. Dialled volume was compared to measured volume. The gas distribution produced by the different ventilators was also studied. It was found that alt lour ventilators could distribute gas to the lungs. The ventilators Logic 07 and Oxylog had acceptable relationships between dialled and measured volume/frequency and they also produced a good final distribution.     

Portable Emergency Ventilators: 2. Sensitivity to Environment

Three compact ventilators (Oxylog, Maxaman and Pneupac 2), commercially available in Sweden, were subjected to tests concerning sensitivity to environmental stress. The ventilators functioned very well at temperatures above 0 degree C. The Oxylog apparatus was very sensitive to subzero temperatures. It also had a spectrum of resonance frequencies when subjected to vibration testing that restricts its use outside the sheltered hospital environment. The Maxaman and Pneupac 2 in the modified version withstood the tests in a reliable way. The shock tests performed had no negative effects on any of the ventilators or their functions.