无创呼吸机治疗慢性阻塞性肺疾病合并严重Ⅱ型呼吸衰竭的临床研究

目的:探讨鼻(面)罩无创正压通气(NIPPV)在慢性阻塞性肺疾病(COPD)合并严重Ⅱ型呼吸衰竭的治疗作用。方法:回顾性研究35例伴严重Ⅱ型呼吸衰竭(PaCO2>80mmHg)的COPD急性发作期患者,在常规治疗基础上给予NIPPV治疗,并监测血气分析、临床征象等情况。结果:NIPPV 3 h迅速改善了患者的血气(PH、PaO2、PaCO2、SaO2)(P<0.05),通气24 h至治疗72 h可获进一步改善(P<0.01)。治疗成功率达88.6%(31/35)。结论:N IPPV是治疗COPD合并严重Ⅱ型呼衰竭的有效手段。     

无创正压通气联合免疫增强治疗老年下呼吸道感染

目的 评价鼻面罩元创正压通气联合免疫增强荆治疗老年下呼吸道感染的疗效。方法 2000年1月-2005年1月该院干医科收治的老年下呼吸道感染患者，随机分为治疗组和对照组。前者采用鼻面罩无创呼吸机正压逦气、参芪挟正液厦常规治疗，对照组采用参芪扶正液及常规治疗。通气前，通气5d后复查血气分析，肺功能和观察呼吸频率、氧饱和度（SaO2）等指标进行分析。结果治疗5d后，呼吸频率较对照组减慢（P〈0．05），SaO2提高（P〈0．05），PaO2增加（P〈0．05），PaCO2降低（P〈0．05），FEV1／FVC改善明显（P〈0．05）。结论 联合免疫增强治疗老年下呼吸道感染，可缩短病程，提高疗效，降低并发症和病死率，无疑是一种新的治疗措施。但对分泌物较多不易咳出的患者。有一定的局限性。     

无创正压通气治疗呼吸衰竭的临床观察及护理

目的:总结应用无创正压通气的护理经验。方法:采用经口鼻面罩应用BiPAPSynchrony呼吸机进行持续正压通气,使用时,向患者做好解释,正确选择呼吸机通气模式和参数,正确使用面罩或鼻罩,保持呼吸道通畅,密切观察病情变化,定时做血气分析。结果:56例中52例患者明显改善了病情,减少有创通气的使用几率,4例患者由于病情恶化,使用无创通气无效,最终使用有创通气。结论:早期应用NIPPV治疗呼吸衰竭,严密的监护是一种极为有效的措施。     

Transcutaneous cardiac pacing

Transvenous cardiac pacing is currently the pacing procedure of choice in patients with severe, life-threatening bradyarrhythmias that do not respond to pharmacotherapy. However, pacing catheters can be difficult to insert and frequently fail to capture in severely hypotensive patients. Therefore, there has been a recent resurgence of interest in external pacing methods. Newer transcutaneous cardiac pacing units are easy to apply and especially suited for unconscious patients with severe, life-threatening bradyarrhythmias. There is no operator danger and, if need be, cardiopulmonary resuscitation can continue while the electrodes are in place and the unit is operating. Human and animal studies to date have shown that there are no significant short-term clinical hazards or pathologic abnormalities when using this technique.     

TECHNICAL NOTE: Continuous non-invasive measurement of mean blood pressure in fingers by volume-clamp and differential oscillometric method

Summary. The present study compares two different methods for non-invasive beat-to- beat finger arterial blood pressure monitoring. The measurements using the volume clamp method (FINAPRES, Ohmeda, USA) were compared with measurements applying the differential oscillometric method (UT9201 device, University of Tartu). 13 healthy volunteers were studied at rest, during head-up tilt (HUT) and during deep breathing (DB) with a fixed rate of 6 breaths/min. Blood pressure was recorded from adjacent fingers of the right hand. 150 pairs of mean blood pressure values in each subject were included for statistical evaluation. No systematic differences between the two methods were found. The difference between values (FINAPRES — UT9201) at rest was -1.1 mmHg (SD 5.5), during HUT 0.5 mmHg (SD 6.9) and during DB-3.6 mmHg (SD 7.7). The insignificant differences between the results obtained by the two independent methods allow us to conclude that both methods give reliable data on finger mean arterial pressure.     

Noninvasive Recording of His-Purkinje System (HPS) Activity in Man on Beat-To-Beat Basis

Since 1969 His bundle electrography has been used for diagnosis and for the study of cardiac electrophysiology. This method has employed the catheterization technique and has allowed the continuous recording of electrical activity of the specialized cardiac conduction system in every beat. Such investigation, because of its invasive nature, cannot be considered a routine test; it requires expensive instrumentation, it has physiological and technical limitations that include discomfort, a slight morbidity risk and a rather limited recorded area within the heart. In 1973 a method was developed for a noninvasive recording of the electrical activity within the P-R segment of the electrocardiogram measured from the body surface. This method which employs the signal averaging technique delivers even less medical information than intracardiac measurement. The shortcomings of this averaging method include inability to detect beat-to-beat changes in the true signal. Such a method is not useful in transient arrhythmia detection and a "short acting" drug influence examination. The technical approach to the beat-to-beat noninvasive recording of the HPS activation signal as measured from the body surface has been proposed. Using a specially positioned electrode system, a low noise multiple parallel input amplifier and a computer for sampling, processing and plotting of the measured signal, we have obtained an output curve corresponding to the continuous beat-to-beat HPS activity.     

Pulmonary infection control window in treatment of severe respiratory failure of chronic obstructive pulmonary diseases: a prospective, randomized controlled, multi-centred study

Background Early withdraw from invasive mechanical ventilation (MV) followed by noninvasive MV is a new strategy for changing modes of treatment. This study was conducted to estimate the feasibility and the efficacy of early extubation and sequential noninvasive MV commenced at beginning of pulmonary infection control window in patients with exacerbated hypercapnic respiratory failure caused by chronic obstructive pulmonary diseases (COPD). Methods A prospective, randomized controlled study was conducted in eleven teaching hospitals’ respiratory or medical intensive care units in China. Ninety intubated COPD patients with severe hypercapnic respiratory failure triggered by pulmonary infection (pneumonia or purulent bronchitis) were involved in the study. When the pulmonary infection had been controlled by antibiotics and comprehensive therapy, the 'pulmonary infection control window (PIC window)' has been reached. Each case was randomly assigned to study group (extubation and noninvasive MV via facial mask immediately) or control group (invasive MV was received continuously after PIC window by using conventional weaning technique).Results Study group (n=47) and control group (n=43) had similar clinical characteristics initially and at the time of PIC window. Compared with control group, study group had shorter duration of invasive MV ［(6.4±4.4) days vs (11.3±6.2) days, P=0.000］, lower rate of ventilator associated pneumonia (VAP) (3/47 vs 12/43, P=0.014), fewer days in ICU ［(12±8) days vs (16±11) days, P=0.047］ and lower hospital mortality (1/47 vs 7/43, P=0.025).Conclusions In COPD patients requiring intubation and invasive MV for hypercapnic respiratory failure, which is exacerbated by pulmonary infection, early extubation followed by noninvasive MV initiated at the start of PIC window may decrease significantly the duration of invasive MV, the risk of VAP and hospital mortality.     

Performance characteristics of 10 home mechanical ventilators in pressure-support mode: a comparative bench study

OBJECTIVE: Inspiratory pressure (Pi) support delivered by a bilevel device has become the technique of choice for noninvasive home ventilation. Considerable progress has been made in the performance and functionality of these devices. The present bench study was designed to compare the various characteristics of 10 recently developed bilevel Pi devices under different conditions of respiratory mechanics. DESIGN: Bench model study. SETTING: Research laboratory, university hospital. MEASUREMENTS: Ventilators were connected to a lung model, the mechanics of which were set to normal, restrictive, and obstructive, that was driven by an ICU ventilator to mimic patient effort. Pressure support levels of 10 and 15 cm H(2)O, and maximum were tested, with "patient" inspiratory efforts of 5, 10, 15, 20, and 25 cm H(2)O. Tests were conducted in the absence and presence of leaks in the system. Trigger delay, trigger-associated inspiratory workload, pressurization capabilities, and cycling were analyzed. RESULTS: All devices had very short trigger delays and triggering workload. Pressurization capability varied widely among the machines, with some bilevel devices lagging behind when faced with a high inspiratory demand. Cycling was usually not synchronous with patient inspiratory time when the default settings were used, but was considerably improved by modifying cycling settings, when that option was available. CONCLUSIONS: A better knowledge of the technical performance of bilevel devices (ie, pressurization capabilities and cycling profile) may prove to be useful in choosing the machine that is best suited for a patient's respiratory mechanics and inspiratory demand. Clinical algorithms to help set cycling criteria for improving patient-ventilator synchrony and patient comfort should now be developed.     

Brief report: Evaluation of an interactive intervention designed to reduce pediatric distress during radiation therapy procedures

OBJECTIVE: To evaluate the efficacy of an interactive intervention in reducing distress related to radiation therapy (RT) among pediatric cancer participants as measured by occurrence of sedation, observed behavioral distress (OBD), and heart rate (HR). METHODS: Seventy-nine children receiving RT simulation were assigned randomly to a STARBRIGHT Hospital Pals group (i.e., interactive intervention group; IG) or modified control group (MCG). The interactive intervention included filmed modeling, exposure to an interactive Barney character, and passive auditory distraction. RESULTS: Children in the IG experienced significantly lower HR when compared with MCG participants. No differences were found in terms of sedation or OBD. CONCLUSIONS: The interactive intervention was effective at reducing RT-related distress (as measured by HR) and would be a useful tool in pediatric radiation oncology settings.     

Focal astrocyte loss is followed by microvascular damage, with subsequent repair of the blood-brain barrier in the apparent absence of direct astrocytic contact

Blood-brain barrier (BBB) breakdown is a feature of cerebral ischaemia, multiple sclerosis, and other neurodegenerative diseases, yet the relationship between astrocytes and the BBB integrity remains unclear. We present a simple in vivo model in which primary astrocyte loss is followed by microvascular damage, using the metabolic toxin 3-chloropropanediol (S-alpha-chlorohydrin). This model is uncomplicated by trauma, ischaemia, or primary immune involvement, permitting the study of the role of astrocytes in vascular endothelium integrity, maintenance of the BBB, and neuronal function. Male Fisher F344 rats given 3-chloropropanediol show astrocytic damage and death at 4-24 h in symmetrical brainstem and midbrain nuclear lesions, while neurons show morphological changes at 24-48 h. Fluorescent 10 kDa dextran tracers show the BBB leaking from 24 h, progressing to petechial haemorrhage after 48-72 h, with apparent repair after 6 days. BBB breakdown, but not the earlier astrocytic death, is accompanied by a delayed increase in blood flow in the inferior colliculus. An ED1 inflammatory response develops well after astrocyte loss, suggesting that inflammation may not be a factor in starting BBB breakdown. This model demonstrates that the BBB can self-repair despite the apparent absence of direct astrocytic-endothelial contact. The temporal separation of pathological events allows pharmacological intervention, and the mild reversible ataxia permits long-term survival studies of repair mechanisms.