Status Of Ventilation Research Articles

Current status and recognition of high frequency ventilation in acute respiratory distress syndrome

Acute respiratory distress syndrome(ARDS) is a common critical disease in pediatric patients, and mechanical ventilation is one of the most important methods for respiratory support.High frequency oscillation ventilation, which has these characteristics of low tidal volume, low airway pressure, and low alveolar injury, is a safe and effective treatment of ARDS.This article will elaborate about current status and recognition of high frequency ventilation in ARDS. Key words: Acute respiratory distress syndrome; High frequency oscillation ventilation; Child

Investigation of Precipitates and Deposits in the Special Piping in Building B at the Bochvar All-Russia Research Institute for Inorganic Materials

The radiation status of the special ventilation and piping systems is investigated as part of the work on the preparation of building B at the Bochvar All-Russia Research Institute for Inorganic Materials for decommissioning. Methods for extracting samples have been developed. Analysis for the content of plutonium isotopes showed that the deposits and precipitates are medium-level wastes.

Nutritional status as a predictor of duration of mechanical ventilation in critically ill children

ObjectivesCritically ill children admitted to the pediatric intensive care unit (PICU) often are malnourished. The aim of this study was to determine the role of nutritional status on admission as a predictor of the duration of mechanical ventilation in critically ill children. MethodsThis was a single-center, prospective cohort study, including consecutive children (ages 1 mo to 15 y) admitted to a PICU. Demographic characteristics, clinical characteristics, and nutritional status were recorded and patients were followed up until hospital discharge. Nutritional status was evaluated by anthropometric parameters and malnutrition was considered if the Z-scores for the parameters were ≤−2. Adjusted Cox's regression analysis was used to determine the association between nutritional status and duration of mechanical ventilation. ResultsIn all, 72 patients were included. The prevalence of malnutrition was 41.2%, according to height-for-age Z-score, 18.6% according to weight-for-height Z-score, and 22.1% according body mass index-for-age Z-score. Anthropometrical parameters that predicted the duration of mechanical ventilation were weight-for-age (hazard ratio [HR], 2.73; 95% confidence interval [CI], 1.44–5.18); height-for-age (HR, 2.49; 95% CI, 1.44–4.28); and upper arm muscle area-for-age (HR, 5.22; 95% CI, 1.19–22.76). ConclusionMalnutrition, based on a variety of anthropometric variables, was associated with the duration of mechanical ventilation in this cohort of critically ill children. Assessment of nutritional status by anthropometry should be performed on admission to the PICU to allow targeted nutritional rehabilitation for the subset of children with existing malnutrition.

Intraoperative Management and Postoperative Outcome in Intestine-Inclusive Liver Transplantation Versus Liver Transplantation

BackgroundAlthough intestine-inclusive liver transplantation (IILT) is performed regularly, its perioperative management has not been studied extensively. MethodsPatients who underwent IILT and isolated liver transplantation (LT) at our center from January 2006 to December 2012 were identified. Among >1,000 LT patients, 90 were selected after matching by age, sex, surgery date, and status of preoperative ventilation for comparison with 45 IILT patients. ResultsThere were no significant differences regarding preoperative variables between the 2 groups except for international normalized ratio. However, IILT patients had significantly higher intraoperative requirement of blood transfusion, incidences of post-reperfusion syndrome, and hyperkalemia compared with LT patients. Postoperatively, IILT patients had significantly longer hospital stay and higher 1-year mortality. Multivariate analysis indicated that IILT was a primary risk factor associated with the studied complications and adverse outcomes. ConclusionsOur findings suggest that, compared with LT patients, IILT patients were more prone to develop intraoperative complications and adverse outcomes and should be closely monitored and aggressively managed.

Influence of ventilation rate on the aerodynamic interference between two extra-large indirect dry cooling towers by CFD

Current wind-resistance designs of large-scale indirect dry cooling towers (IDCTs) exclude an important factor: the influence of the ventilation rate for radiator shutter on wind loads on the outer surfaces of the tower shell. More seemingly overlooked aspects are the effects of various ventilation rates on the wind pressure distribution on the tower surfaces of two IDCTs, and the feature of the flow field around them. In order to investigate the effects of the radiator shutter ventilation rates on the aerodynamic interference between IDCTs, this paper established the numerical wind tunnel model based on the Computational Fluid Dynamic (CFD) technology, and analyzed the influences of various radiator shutter ventilation rates on the aerodynamic loads acting upon a single and two extra-large IDCTs during building, installation, and operation stages. Through the comparison with the results of physical wind tunnel test and different design codes, the results indicated that: the influence of the ventilation rate on the flow field and shape coefficients on the outer surface of a single IDCT is weak, and the curve of mean shape coefficients is close to the reference curve provided by the current design code. In a two-tower combination, the ventilation rate significantly affects the downwind surface of the front tower and the upwind surface of the back tower, and the larger positive pressure shifts down along the upwind surface of the back tower as the ventilation rate increases. The ventilation rate significantly influences the drag force coefficient of the back tower in a two-tower combination, the drag force coefficient increases with the ventilation rate and reaches the maximum in a building status of full ventilation, and the maximum drag coefficient is 11% greater than that with complete closure.

Preoperative Determinants of Outcomes of Infant Heart Surgery in a Limited-Resource Setting

We studied the effect of preoperative determinants on early outcomes of 1028 consecutive infant heart operations in a limited-resource setting. Comprehensive data on pediatric heart surgery (January 2010-December 2012) were collected prospectively. Outcome measures included in-hospital mortality, prolonged ventilation (>48 hours), and bloodstream infection (BSI) after surgery. Preoperative variables that showed significant individual association with outcome measures were entered into a logistic regression model. Weight at birth was low in 224 infants (21.8%), and failure to thrive was common (mean-weight Z score at surgery was 2.72 ± 1.7). Preoperatively, 525 infants (51%) needed intensive care, 69 infants (6.7%) were ventilated, and 80 infants (7.8%) had BSI. In-hospital mortality (4.1%) was significantly associated with risk adjustment for congenital heart surgery-1 (RACHS-1) risk category (P < 0.001). Neonatal status, preoperative BSI, and requirement of preoperative intensive care and ventilation had significant individual association with adverse outcomes, whereas low birth weight, prematurity, and severe failure to thrive (weight Z score <-3) were not associated with adverse outcomes. On multivariable logistic regression analysis, preoperative sepsis (odds ratio = 2.86; 95% CI: 1.32-6.21; P = 0.008) was associated with mortality. Preoperative intensive care unit stay, ventilation, BSI, and RACHS-1 category were associated with prolonged postoperative ventilation and postoperative sepsis. Neonatal age group was additionally associated with postoperative sepsis. Although severe failure to thrive was common, it did not adversely affect outcomes. In conclusions, preoperative BSI, preoperative intensive care, and mechanical ventilation are strongly associated with adverse outcomes after infant cardiac surgery in this large single-center experience from a developing country. Failure to thrive and low birth weight do not appear to adversely affect surgical outcomes.

Associations between Natural Ventilation for the Child's Bedroom during Night and Childhood Asthma in Shanghai, China

From March 2013 to December 2014, we conducted a case-control study and inspected 454 residences with asthmatic or non-asthmatic children from six districts in Shanghai. Carbon dioxide (CO2) were passively measured 24hours in the child's bedroom. We took the average concentration of CO2 during 00:00 to 06:00 as an indicator for the status of natural ventilation in the child's bedroom during night and investigated its association with childhood asthma. A total of 45.6% (n = 203) residences had CO2 average concentrations higher than 1000ppm. The mean CO2 concentration ± standard deviation was 1123 ± 741ppm (range: 367 to 4595ppm). CO2 average concentrations in the residences measured in autumn and in summer were significantly lower than measured in winter. No significant differences were found among CO2 average concentrations among Case group and Control group in total and in different measured seasons. More deeply analyses were warranted.

Impact of prenatal diagnosis in survivors of initial palliation of single ventricle heart disease: analysis of the National Pediatric Cardiology Quality Improvement Collaborative database.

Among infants with single ventricle congenital heart disease (SVD) requiring Stage I palliation (S1P), the impact of prenatal diagnosis (PD) on outcomes has been variably characterized. We investigated the impact of PD in a large multi-center cohort of survivors of S1P in the National Pediatric Cardiology Quality Improvement Collaborative (NPCQIC) registry. Retrospective analysis of demographic and outcomes data among infants enrolled in the NPCQIC database; eligibility includes SVD requiring S1P and survival to discharge. From 43 contributing surgical centers, 591 infants had data available through time of BDG (519) or interstage death (55). Median gestational age was 39 weeks (31-46), and 66% had variants of hypoplastic left heart syndrome. PD was made in 445 (75%), with significant variation by center (p = 0.004). While infants with PD had slightly lower gestational age at birth (p < 0.001), there were no differences in birth weight, the presence of major syndromes or other organ system anomalies. Those without PD were more likely to have atrioventricular valve regurgitation (p = .002), ventricular dysfunction (p = 0.06), and pre-operative risk factors including acidosis (p < 0.001), renal insufficiency (p = 0.007), and shock (p = 0.05). Post-operative ventilation was shorter in the PD group (9 vs. 12 d, p = 0.002). Other early post-operative outcomes, interstage course, and outcomes at BDG were similar between groups. In a large cohort of infants with SVD surviving to hospital discharge after S1P, PD showed significant inter-site variation and was associated with improved pre-operative status and shorter duration of mechanical ventilation. The significance of such associations merits further study.

P182 COPD: Is it all in vein?

Introduction & ObjectivesIn patients with COPD, an arterial blood gas (ABG) is considered the gold standard method of directly measuring serum pH, pO2, pO2 and calculating bicarbonate (HCO3) levels. These...

Transcranial cerebral oximetry in newborn infants on mechanical ventilation as a method for prevention of hyperoxia and oxidative stress

The aim of this research was the effectiveness of respiratory therapy in infants with respiratory distress syndrome (RDS) who are ventilated by correcting the oxygen status and parameter optimization of ventilation by determining the oxygen saturation in the brain by transcranial cerebral oximetry (TCO).

Echocardiographic Measures of Diastolic Function Are Preload Dependent during Triggered Positive Pressure Ventilation: A Controlled Crossover Study in Healthy Subjects

Background. The use of echocardiography in intensive care settings impacts decision making. A prerequisite for the use of echocardiography is relative resistance to changes in volume status and levels of positive pressure ventilation (PPV). Studies on indices of diastolic function report conflicting results with regard to dependence on volume status. Evidence is scarce on PPV. Methods. Ten healthy subjects were exposed to 6 levels of positive end-expiratory pressure (PEEP) and pressure support (PS) following a baseline reading. All ventilator settings were performed at three positions: horizontal, reverse-Trendelenburg, and Trendelenburg. Echocardiography was performed throughout. Results. During spontaneous breathing, early diastolic transmitral velocity (E) changed with positioning (P < 0.001), whereas early diastolic velocity of the mitral annulus (e′) was independent (P = 0.263). With PPV, E and e′ proved preload dependent (P values < 0.001). Increases in PEEP, PS, or a combination influenced E and e′ in reverse-Trendelenburg- and horizontal positions, but not in the Trendelenburg position. Discussion. The change towards preload dependency of e′ with PPV suggests that PPV increases myocardial preload sensitivity. The susceptibility of E and e′ to preload changes during PPV discourages their use in settings of volume shifts or during changes in ventilator settings. Conclusion. Positioning and PPV affect E and e′.

Data mining applications in evaluating mine ventilation system

A mine’s ventilation system is an important component of an underground mining system. It provides a sufficient quantity of air to maintain suitable working environment. Therefore, the status of mine ventilation should be tracked and monitored as a timely matter. Based on former findings and in-depth analysis of mine ventilation systems, a proper early warning model is proposed in this paper for such considerations to improve the mine ventilation safety. The model itself is comprised of two sub-models, and two data mining techniques are used to assist in building each sub-model. One is the optimal indexes selection model which applies the Rough Set theory (RS) to assist the selection of best ventilation indexes. The other is the risk evaluation model based on the Support Vector Machine (SVM) to classify the risk ranks for the mine ventilation system. Testing cases have been used to demonstrate the applicability of this integrated model.

An Overview on Indoor Air Pollution, Its Adverse Health Effects, and Intervention Measures in Rural China

PP-29-147 Background/Aims: To understand the status of indoor air pollution (IAP), its adverse health effect and the intervention measures against IAP in rural China, and provide a clue for the further research and prevention. Methods: Literatures about IAP, its adverse effect and related intervention measures in rural areas of China published in Chinese language from 1999 through 2010 were collected and summarized. Results: In rural areas of northern China, coal burning for household heating in winter is the major impacting factor of IAP for the moment. Moreover, type of fuels, status of combustion and ventilation, and house structure can also put an important influence on indoor air quality. For this reason, the level of IAP in rural areas of China may vary in regions and seasons. It is concluded that there is certain relationship between IAP and the prevalence of COPD, lung cancer, as well as some respiratory symptoms and decrease of women lung function. When it comes to intervention actions, using improved stoves and clean energy can directly and effectively improve indoor air quality. Furthermore, health education, behavior intervention, and social mobilization were provided to achieve the purpose of improving indoor air quality by helping people change unhealthy lifestyle. Conclusion: Household fuel burning is the main source of IAP in rural China. IAP can affect the residents' health, causing diseases such as COPD, lung cancer, and so on. The measures such as furnace and stove improvement, health education and behavior intervention, development and use of clean energy, social mobilization can attenuate indoor air pollution.

Current status of pediatric home mechanical ventilation in Japan

The first nationwide survey of pediatric home mechanical ventilation (HMV) was conducted. From 35 out of 149 medical centers investigated, 49 cases of HVM were reported. The patients ranged in age from 1 to 20 years, and the causes of respiratory failure were neuromuscular diseases (51%), central hypoventilation (33%), respiratory disorders (10%) and cervical cord injury (6%). Since 1983 when 2 patients were discharged home on mechanical ventilation, more and more ventilator-dependent children have been sent home every year. However, home mechanical ventilation is not yet well recognized in Japan as an option for pediatric patients with chronic respiratory failure, and there are many problems to be solved. Firstly, very few, if any, hospitals have a designated home care team composed of physicians and other specialists. Secondly, the current health insurance system scarcely covers the cost of home ventilation. Thirdly, development of home use equipment, in particular, portable ventilators and monitors is imperative. There are 107 hospitalized patients in 56 institutions who are reportedly able to go home if a support system is established. A program for pediatric home mechanical ventilation should be urgently developed on a national basis.

Exposure to rubber process dust and fume since 1970s in the United Kingdom; influence of origin of measurement data

The objective of this study was to compare measured concentrations of rubber process dust and rubber fume originating from different sources in the British rubber manufacturing industry. Almost 8000 exposure measurements were obtained from industry-based survey results collected by the British Rubber Manufacturers' Association (BRMA), and covering the years 1977 to 2002, and from a series of small surveys contained in the Health and Safety Executive's (HSE) National Exposure Database (HSE-NEDB) from 1980 to 2002. The analysis investigated temporal trends in the exposure concentrations and the underlying main factors responsible for these changes. Analyses were carried out using hierarchical linear mixed effects models. Average personal exposures to rubber process dust and rubber fumes were respectively a factor 2 and 4 higher for the HSE-NEDB data when compared to data originating from the industry (BRMA data). Personal exposure to rubber process dust decreased on average by 4.1% (95% CI 4.7-3.6) annually for the BRMA data and slightly less at 2.3% (95% CI 5.2-0.7%) per annum for the HSE-NEDB data. Personal exposure to rubber fume also showed a downward temporal trend of 2.9% (95% CI 3.6-2.3%) and 4.8% (95% CI 7.4-2.1%) annually for the BRMA and HSE-NEDB data, respectively. These trends differed considerably between departments. No major changes in the estimated temporal trends in exposure concentrations were observed after including the presence of local exhaust ventilation in the models for any department in the BRMA and HSE-NEDB datasets. Lack of information on the quality and status of the local exhaust ventilation is the most likely explanation for this. In conclusion, even though there were relatively similar downward time trends in both rubber process dust and fume concentrations in both datasets, the source of exposure data was an important determinant of average exposure concentrations present in the British rubber manufacturing industry. Lack of detailed auxiliary information on company size, reason for sampling, measurement strategy and other potentially important determinants of exposure prevented an explanation for the observed differences in exposure level.

The sitting position in neurosurgery — Unresolved hemodynamic consequences!

ONTROVERSY continues to surround use of the sitting position for neurosurgical procedures. 1–3 The seated position, while presenting a number of challenges for the anesthesiologist, offers many surgical advantages for patients undergoing posterior fossa and cervical spine procedures. Specifically, the upright position improves operator orientation and surgical access to midline lesions in many posterior fossa cases. Gravitational drainage of venous blood from the surgical field and lowering of intracranial pressure increases technical ease and allows more rapid access to bleeding points. 4 An unobstructed view of the face allows motor responses to cranial nerve stimulation to be directly observed in the sitting position, and access to the anterior chest wall is facilitated in the event of cardiovascular collapse. Despite the many advantages offered from the surgical perspective, the sitting position presents unique physiological challenges for the anesthesiologist with the potential for serious complications. 1,5 Venous air embolism, with or without paradoxical air embolism, is a major concern in relation to the use of this position. 2,6 Hemodynamic instability with hypotension and potential compromise of cerebral and myocardial perfusion may occur. Reduction of inhaled volatile anesthetic agent and decreasing depth of anesthesia may predispose the seated patient to the risk of intraoperative awareness. Peripheral neuropathy 1 tension pneumocephalus, 7 and quadriplegia 1,2 are additional reported associated complications. The hemodynamic effects of anesthesia in the sitting position may be influenced by choice of ventilatory technique. Spontaneous ventilation with a volatile anesthetic agent in nitrous oxide/oxygen was popular in the 1960’s to provide signs of surgical encroachment on vital medullary and pontine structures. 8 The problems of cardiovascular instability and arterial hypotension associated with the upright position may be aggravated by the depressant effects of intravenous induction and volatile agents on myocardial contractility during general anesthesia and changes in venous return following intermittent positive pressure ventilation. 9 The volume of blood accumulating in the venous system may be influenced by patient factors - body mass index, intravascular volume status, pre-existing hypertension and mode of ventilation. As much as 1500 mL may be sequestered in the venous system of the lower limbs due to the effect of gravity 10 and increased diffusion through the capillary walls and venous dilatation associated with the use of volatile anesthetic agents. 11 Indicator dilution technique studies have confirmed a 14% redistribution of blood volume from the intra- to the extrathoracic compartment in anesthetized patients after a change from the supine to the sitting position. 12 Concomitant changes in arterial pressure and stroke volume index were thus attributed to alterations in cardiac preload. A number of techniques have been advocated to attenuate the hemodynamic effects of patient placement in the sitting position. Colloid preloading (10 mL·kg –1 ) 30 min before starting general anesthesia was reported to prevent decreases in systolic and central venous pressures during sitting patient positioning without adverse effects. 13 Compensatory mechanisms, perhaps mediated by the renin-angiotensin-aldosterone system or the sympathetic nervous system, may be operative in the awake or anesthetized state to attenuate adverse hemodynamic changes associated with the sitting position. Wrapping of the legs, application of anti-gravity suits and positioning of the knees at right heart level may all have potential benefits.

Current status of noninvasive ventilation in stable COPD patients

Noninvasive ventilation (NIV) has been one of the major advances in respiratory medicine in the last decade. NIV improves quality of life, prolongs survival, and improves gas exchange and sleep quality in restrictive patients, but evidence available now does not allow us to establish clear criteria for prescribing NIV in patients with chronic respiratory failure due to COPD. On the basis of the available studies, NIV should not be used as a treatment of choice for all patients with COPD, even when disease is severe. However, there is more evidence that NIV has an important effect in these patients. In fact, a selected group of patients may well benefit from domiciliary mechanical ventilation, and we need to be able to identify who they are. Moreover, NIV can be a new strategy to improve exercise tolerance in COPD patients.

Review of research into and application of chilled ceilings and displacement ventilation systems in Europe

This paper discusses the origination, development and current status of chilled ceilings, displacement ventilation and combined systems. Current knowledge of chilled ceilings (including ceiling panels and beams), displacement ventilation and combined systems is summarised and a comprehensive review of research into chilled ceilings and displacement ventilation systems is presented. Research work has been categorized, and some conclusions made. Opportunities for further work are discussed. Copyright © 2004 John Wiley & Sons, Ltd.

Enhancement of natural ventilation in high-rise residential buildings using stack system

This paper describes the feasibility study on the application of passive and active stack systems to enhance natural ventilation in public housing in Singapore. About 86% of the population is staying in high-rise public housing, known as Housing and Development Board (HDB) flats, which is designed for natural ventilation. The primary objective of this work is to assess the status of natural ventilation in a typical four-room HDB flat using scaled model in the wind tunnel, and to develop an effective passive or active stack system to enhance natural ventilation in the flat. Four numbers of stacks with different sizes were tested at two locations in the flat. The study shows that the passive stack, incorporating the principle of airflow due to buoyancy, does not enhance air velocity in the flat. However, the active stack which operates based on the suction effect induced by a fan fixed at the top of the stack leads to substantial increase in the air velocity at the room and thus meeting the human’s thermal comfort condition. It was noted that the velocities increase along with the increase in the stack size.

Current status of non-invasive ventilation in German ICU's -- a postal survey

The status of non-invasive ventilation (NIV) in intensive care units (ICU) in Germany was analysed by a national survey. Questionnaires consisting of multiple-choice and short-answer questions were sent to ICUs of university hospitals, hospitals with >1000 beds, with 500 - 1000 beds, and hospitals with <500 beds separated with regard to different specialties (anesthesia ICUs, surgical ICUs, cardiac surgical ICUs, neurosurgical ICUs, internal ICUs, interdiscipline ICUs). Of the 716 questionnaires sent 223 (32 %) were returned and analysed. The use of NIV in all specialties increased during the last 3 years. 14 % of ICUs in some specialties treated more than 30 % of patients with NIV. CPAP (88 %), BIPAP (45 %) and ASB/PSV (48 %) were most frequently used as NIV-strategies. 10 % of all ICUs reported to have experience with proportional assist ventilation. NIV was most frequently used for disease states like COPD (82 %), pneumonia (64 %), pulmonary oedema (50 %), bronchial asthma (35 %) and ALI/ARDS (22 %). The use of NIV was considered when clinical signs of ventilation (93 %) and oxygenation [arterial blood gas analysis (92 %) and oxygen saturation (66 %)] were inadequate. Complications observed during NIV were panic reaction (83 %), ulceration of nose (38 %) and aspiration (14 %). The reasons to reject NIV were (total 13 %): lack of ventilators (64 %), expenditure of personnel (57 %) and risk of the procedure (11 %). 38 % of the ventilators used were older than 5 years. 56 % of the ICUs were content with the equipment for NIV. 76 % of the ICUs were interested to buy new equipment of NIV. 99 % of the survey have declined NIV as an alternative method of ventilation. In summary we found NIV as an accepted additional method of ventilatory support in respiratory failure in German ICUs. We found no significant increase in frequency of NIV in the last three years.