Ventilatory support in the intensive care unit

This article focuses on the functional features of positive-pressure ventilators, the modes of invasive and non-invasive mechanical ventilation, and the main ventilator settings. It also highlights the potential complications of mechanical ventilation, the basic principles of weaning, and the pathophysiological basis of patient-ventilator dyssynchrony.     

运动学对线应用于全膝关节置换术的研究进展

全膝关节置换术是目前治疗终末期膝关节骨性关节炎最有效的方法之一，全膝关节置换术后膝关节功能、术后膝关节疼痛与术后下肢力线有着密切的关系。目前膝关节置换术下肢对线方式主要采用机械力学对线方法，该方法可以改善膝关节功能，但是有部分患者也会产生术后膝关节的疼痛、活动受限等并发症，导致术后患者满意度较差。近些年越来越多的研究开始关注运动力学对线技术并应用于临床。运动学对线技术旨在重建患者的解剖结构，将膝关节假体运动轴与膝关节生理性运动轴保持一致，减少膝关节周围软组织和韧带的松解，实现膝关节生理性运动。该文就运动力学对线方法在全膝关节置换术中的应用进展作一综述。     

Delivery during extracorporeal membrane oxygenation (ECMO) support of pregnant woman with severe respiratory distress syndrome caused by influenza: a case report and review of the literature

Objective: To report a case of labour induction during extracorporeal membrane oxygenation (ECMO) support in a patient with acute respiratory distress syndrome (ARDS) caused by influenza and review of the literature.

Methods: Case report and the literature search of all English articles on delivery while on ECMO in patients with ARDS caused by influenza.

Results: A 25-year-old pregnant woman was initiated with ECMO due to severe ARDS caused by influenza A (H1N1) virus. When the patient had symptoms of colporrhagia and uterine contractions, the medical team decided to start labour induction while on ECMO. There were in total five case reports identified. Maternal oxygenation was improved after delivery and ECMO was successfully discontinued.

Conclusions: Maternal oxygenation was improved after delivery, which may be beneficial to reduce the duration of ECMO. Caesarean section (CS) may be the most used mode and labour induction could be another option. The procedure should be performed by an experienced ECMO team, cooperating with the obstetrician, anaesthesiologist, and ICU doctors.     

Novel explant model to study mechanotransduction and cell-cell communication.

To understand in situ behavior of osteocytes, we characterized a model of osteocytes in their native bone matrix and demonstrated real-time biologic activity of osteocytes while bending the bone matrix. Using 43 male Sprague-Dawley rats, dumbbell-shaped explants were harvested from stainless steel femoral implants after 6-12 weeks and incubated in culture medium or fixed. Sixteen specimens were used to determine bone volume density (BV/TV), volumetric bone mineral density (BMD) and histology for different implantation periods. Osteocyte viability was evaluated by L-lactate dehydrogenase (LDH) activity in 12 cultured explants. Confocal microscopy was used to assess tracer diffusion in three explants and changes in osteocyte pH of a mechanically loaded explant. From 6 to 12 weeks, explant BV/TV and volumetric BMD trended up 92.5% and 101%, respectively. They were significantly and highly correlated. Tissues were uniformly intramembranous and all bone cell types were present. Explants maintained LDH activity through culture day 8. Diffusion at 200 microM was limited to 1,209 Da. Explants appeared capable of reproducing complex bone biology. This model may be useful in understanding osteocyte mechanotransduction in the context of a physiologically relevant bone matrix.     

An XPS and SEM evaluation of six chemical and physical techniques for cleaning of contaminated titanium implants

The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed.     

Efficacy of an air-cleaning device equipped with a high efficiency particulate air filter in house dust mite respiratory allergy

The efficacy of an air-cleaning device equipped with a high efficiency particulate air (HEPA) filter (without further avoidance measures) was studied in patients allergic to house dust mite. The effects of the air-cleaner on indoor Dermatophagoides sp. levels, symptom score and bronchial hyperresponsiveness in nine mite-allergic patients were assessed using a cross-over controlled study. No significant effect was demonstrated on indoor Dermatophagoides sp. levels when comparing the period of air-cleaner activity (2 months) with the control period (2 months). The Dermatophagoides sp. levels in the houses studied were lower than the risk level for asthmatic attacks, making it difficult to assess any effect on asthma; however, neither bronchial hyperresponsiveness nor rhinitis symptom score were changed by air-cleaner activity. During the trial period, however the mean level of Dermatophagoides sp. allergen in the houses changed spontaneously from 4.4 micrograms/g (mean level in the first 2 trial months) to 1.75 micrograms/g of dust (second 2 months) (P less than 0.05). Owing to this change, the mean rhinitis symptom score also decreased (P less than 0.05), even if no significant correlation was demonstrated (r = 0.4 P = 0.089). HEPA filter air-cleaners appear insufficient as substitutes for standard avoidance measures in mite allergic patients.     

人工心肺机血液泵监测系统的研制

为避免人工心肺机血液泵转速失控现像的发生，特研制人工心肺机监测系统，通过对血泵转速的实时监测，判断系统是否正常，自动进行相应的处理，提高现有系统的安全性。     

橡胶活性官能团对增韧环氧树脂动态力学性能的影响

用动态扭摆法测试聚丙烯酸丁酯橡胶增韧环氧树脂的动态力学行为,研究在环氧树脂低固化度和高固化度时,橡胶活性官能团种类(环氧基官能团与羧基官能团)和数量(官能度)对其影响。研究体系中橡胶玻璃化转变温度(Tg)的移动大小,与橡胶和基体树脂健合程度之间的关系。     

Endoscopic sphincterotomy for common bile duct stones: Impact of recent technical advances

Technical improvements, such as mechanical lithotripsy, stenting or nasobiliary drainage, and wire-guided cannulation, have reduced the risk of complications in endoscopic sphincterotomy. To determine the extent of this reduction in risk, we assessed the medical records of 1352 patients with common bile duct stones in whom the procedure was conducted. Complications examined were: acute cholangitis and pancreatitis. Stone clearance was achieved in 1256 patients (92.8%), with an overall morbidity rate of 7.7% and a mortality rate of 0.15%. One hundred and forty-two patients had stones with a diameter greater than 20mm; 97 of these patients did not undergo lithotripsy. Cholangitis occurred in 10 of these 97 patients (10.3%), whereas, in the 45 patients who underwent lithotripsy, there were no cases of cholangitis (P=0.02). Stone removal was not immediately accomplished or attempted in 396 patients. In 82 of these patients in whom a stent or a nasobiliary drain was placed in the common bile duct, the incidence of cholangitis was 1.2%, significantly less (P=0.045) than the incidence of 6.4% in the other 314 patients given no stenting or nasobiliary drain. To overcome difficult cannulation, precut sphincterotomy was conducted in 134 patients and wireguided sphincterotomy, a recently introduced procedure, was conducted in 55 patients. When the precutting technique was used, the incidence of acute pancreatitis was significantly higher (8/134; 6.0%) than that in the patients in whom the standard procedure was conducted, i.e., neither the precut technique nor wire-guided ES was used (23/1218; 1.9%) (P=0.008). There were no cases of pancreatitis in the 55 patients in whom wire-guided sphincterotomy was performed, although the difference was not statistically significant because of the small number of patients (P=0.06). Based on these findings, we conclude that improved technologies have led to a significant reduction of complications in endoscopic sphincterotomy.     

Personal history,training, and worksite as predictors of back pain of nurses

Back pain among nurses is a common problem. Prior studies of this problem have been based on cross-sectional or retrospective data. This 18-month prospective study involving nurses newly graduated from nursing school investigated personal, worksite, and training factors associated with future risk of back pain. Each nurse underwent a preliminary interview and periodic follow-ups to identify those with back injuries. Contingency tables and logistic regression analyses demonstrated that prior significant back pain episodes (evidenced by previous job changes because of back pain, frequent medication use, etc.) were associated with increased future risk. Training at nursing school or on the job did not have a protective effect. This pilot study therefore suggests factors useful in placement and counseling of new nurses and indicates the need for further implementation of mechanical lift assist device use. © 1994 Wiley-Liss, Inc.