Prevention of ventilator-associated pneumonia with inhaled antibiotics

The direct delivery of inhaled antibiotics to the respiratory tract has been a subject of enduring interest among medical practitioners and researchers due to the associated favorable pharmacokinetics.This interest has been particularly pronounced in the context of critically illpatients,wherehealthcare-associatedpulmonary infections represent a significant challenge,driving continued exploration of inhaled antibiotics for intubated patients.Recent high-level evidence has shown a very promising application in the field of ventilator-associated pneumonia (VAP) prevention.^([1]).

Analysis of the Effect of Extracorporeal Diaphragmatic Pacing Combined with Noninvasive Ventilator on the Respiratory Function and Prognosis of COPD Patients

Objective: To investigate the effect of extracorporeal diaphragmatic pacing combined with noninvasive ventilators on the respiratory function and prognosis of chronic obstructive pulmonary disease (COPD) patients. Methods: A total of 50 COPD patients were selected between January 2023 to December 2023 and randomly grouped into an observation group and a control group, with 25 cases. The observation group was given extracorporeal diaphragm pacing combined with a noninvasive ventilator, while the control group was given a conventional treatment mode. After the treatment, the results of each index in the two groups were compared. Results: Compared with the diaphragm function indexes of the two groups, the data of the observation group were more dominant (P < 0.05). The rehospitalization rate of the observation group was lower than that of the control group (P < 0.05). The COPD assessment test (CAT) and mMRC (Modified Medical Research Council) Dyspnoea scale scores after treatment between the two groups were significantly different (P < 0.05). Compared with the control group, the lung function indexes of the observation group were more dominant (P < 0.05). Conclusion: Extracorporeal diaphragmatic pacing combined with a noninvasive ventilator promoted the improvement of the patient’s prognosis and improved their respiratory function.

Observation on the Effect of Non-Invasive Ventilator Combined with Conventional Therapy in the Treatment of Chronic Obstructive Pulmonary Disease Complicated with Respiratory Failure

Objective:To explore the clinical effect of a non-invasive ventilator combined with conventional therapy in the treatment of patients with chronic obstructive pulmonary disease(COPD)combined with respiratory failure.Methods:68 patients with COPD combined with respiratory failure treated in our hospital from September 2021 to October 2023 were selected as the research subjects.Using the random number table method,they were divided into a control group and an experimental group of 34 cases each.The control group received conventional symptomatic treatment,and the experimental group received non-invasive ventilator treatment based on the control group.The clinical effects,blood gas indicators(partial pressure of carbon dioxide(PaCO_(2)),partial pressure of oxygen(PaO_(2)),arterial oxygen saturation(SaO_(2))),lung function(forced expiratory volume in 1 second(FEV1),forced vital capacity(FVC),6 min walking distance),complications,and inflammatory factor levels(c-reactive protein(CRP),interleukin-6(IL-6),neutrophil-to-lymphocyte ratio(NLR))of the two groups of patients were observed.Results:(1)The clinical efficacy of the patients in the experimental group(33/97.06%)was more significant as compared with the control group(25/73.53%)(P<0.05);(2)After treatment,the clinical efficacy of the two groups of patients in terms of FEV1,FEV1/FVC,6-minute walking distance,PaO_(2)and SaO_(2)all increased in the experimental group as compared to that of the control group(P<0.05);(3)After treatment,the PaCO_(2),CRP,IL-6,and NLR of the two groups of patients decreased,and the decrease in the experimental group was higher than that of the control group(P<0.05);(4)The patients’complication rate in the experimental group(2/5.88%)was lower as compared to that of the control group(9/26.46%)(P<0.05).Conclusion:Non-invasive ventilators combined with conventional therapy achieved good clinical results in treating patients with COPD and respiratory failure.

VIBRATION CHARACTERISTIC INVESTIGATION OF COUNTER-ROTATING DUAL-ROTOR IN AERO-ENGINE

Two methods for vibration characteristic investigation of the counter-rotating dual-rotors in an aero-en- gine are put forward. The two methods use DAMP tool on the MSC. NASTRAN platform and develope the re- solving sequence. Vibration characteristics of a turbofan engine are analyzed by using the two methods. Com- pared with results calculated using transfer matrix method and test results, the two methods are valuable and have great potential in practical applications for vibration characteristic investigation of aero-engines with high thrust-weight ratio.

VIBRATION NUMERICAL ANALYSIS OF COUNTER-ROTATING TURBINE WITH WAKE-FLOW USING FLUID-STRUCTURE INTERACTION METHOD

The design of counter-rotating turbine is one of new techniques to improve the thrust-weight ratio of jet propulsion engines.Numerical analysis of a low pressure（LP）counter-rotating turbine rotor blade is presented by using ANSYS/CFX software.Interaction of aerodynamics and solid mechanics coupling in the computation is applied.In some rating of turbine,stress distribution and vibration characteristics of low pressure turbine（LPT）blade are computed.The wake aerodynamic forces and LPT blade vibration are transformed in frequency domain using fast Fourier transform（FFT）method.The results show that under wake aerodynamic force excitation,the first order modal vibration is more easily aroused and the higher order response cannot be ignored.Moreover,with different temperature fields,the vibration responses of blade are also different.

Risk factors for ventilator-associated pneumonia in trauma patients:A descriptive analysis

BACKGROUND:We sought to evaluate the risk factors for developing ventilator-associated pneumonia(VAP)and whether the location of intubation posed a risk in trauma patients.METHODS:Data were retrospectively reviewed for adult trauma patients requiring intubation for>48 hours,admitted between 2010 and 2013.Patients’demographics,clinical presentations and outcomes were compared according to intubation location(prehospital intubation[PHI]vs.trauma room[TRI])and presence vs.absence of VAP.Multivariate regression analysis was performed to identify predictors of VAP.RESULTS:Of 471 intubated patients,332 patients met the inclusion criteria(124 had PHI and208 had TRI)with a mean age of 30.7±14.8 years.PHI group had lower GCS(P=0.001),respiratory rate(P=0.001),and higher frequency of head(P=0.02)and chest injuries(P=0.04).The rate of VAP in PHI group was comparable to the TRI group(P=0.60).Patients who developed VAP were 6 years older,had significantly lower GCS and higher ISS,head AIS,and higher rates of polytrauma.The overall mortality was 7.5%,and was not associated with intubation location or pneumonia rates.In the early-VAP group,gram-positive pathogens were more common,while gram-negative microorganisms were more frequently encountered in the late VAP group.Logistic regression analysis and modeling showed that the impact of the location of intubation in predicting the risk of VAP appeared only when chest injury was included in the models.CONCLUSION:In trauma,the risk of developing VAP is multifactorial.However,the location of intubation and presence of chest injury could play an important role.

Effects of Shielding Coatings on the Anode Shaping Process during Counter-rotating Electrochemical Machining

Electrochemical machining （ECM） has been widely used in the aerospace, automotive, defense and medical industries for its many advantages over traditional machining methods. However, the machining accuracy in ECM is to a great extent limited by the stray corrosion of the unwanted material removal. Many attempts have been made to improve the ECM accuracy, such as the use of a pulse power, passivating electrolytes and auxiliary electrodes. However, they are sometimes insufficient for the reduction of the stray removal and have their limitations in many cases. To solve the stray corrosion problem in CRECM, insulating and conductive coatings are respectively used. The different implement processes of the two kinds of coatings are introduced. The effects of the two kinds of shielding coatings on the anode shaping process are investigated. Numerical simulations and experiments are conducted for the comparison of the two coatings. The simulation and experimental results show that both the two kinds of coatings are valid for the reduction of stray corrosion on the top surface of the convex structure. However, for insulating coating, the convex sidewall becomes concave when the height of the convex structure is over 1.26 ram. In addition, it is easy to peel off by the high-speed electrolyte. In contrast, the conductive coating has a strong adhesion, and can be well reserved during the whole machining process. The convex structure fabricated by using a conductive iron coating layer presents a favorable sidewall profile. It is concluded that the conductive coating is more effective for the improvement of the machining quality in CRECM. The proposed shielding coatings can also be employed to reduce the stray corrosion in other schemes of ECM.

Ventilator associated pneumonia following liver transplantation:Etiology,risk factors and outcome

AIM: To determine the incidence, etiology, risk factors and outcome of ventilator-associated pneumonia(VAP) in patients undergoing orthotopic liver transplantation(OLT).METHODS: This retrospective study considered 242 patients undergoing deceased donor OLT. VAP was diagnosed according to clinical and microbiological criteria. RESULTS: VAP occurred in 18(7.4%) patients, with an incidence of 10 per 1000 d of mechanical ventilation(MV). Isolated bacterial etiologic agents were mainly Enterobacteriaceae(79%). Univariate logistic analysis showed that model for end-stage liver disease(MELD) score, pre-operative hospitalization, treatment with terlipressin, Child-Turcotte-Pugh score, days of MV and red cell transfusion were risk factors for VAP. Multivariateanalysis, considering significant risk factors in univariate analysis, demonstrated that pneumonia was strongly associated with terlipressin usage, pre-operative hospitalization, days of MV and red cell transfusion. Mortality rate was 22% in the VAP group vs 4% in the group without VAP. CONCLUSION: Our data suggest that VAP is an important cause of nosocomial infection during postoperative period in OLT patients. MELD score was a significant risk factor in univariate analysis. Multiple transfusions, treatment with terlipressin, preoperative hospitalization rather than called to the hospital while at home and days of MV constitute important risk factors for VAP development.

Ventilator management for acute respiratory distress syndrome associated with avian infl uenza A(H7N9) virus infection: A case series

BACKGROUND: Data on the mechanical ventilation(MV) characteristics and radiologic features for the cases with H7 N9-induced ARDS were still lacking.METHODS: We describe the MV characteristics and radiologic features of adult patients with ARDS due to microbiologically confirmed H7 N9 admitted to our ICU over a 3-month period.RESULTS: Eight patients(mean age 57.38±16.75; 5 male) were diagnosed with H7 N9 in the first quarter of 2014. All developed respiratory failure complicated by acute respiratory distress syndrome(ARDS), which required MV in ICU. The baseline APACHE II and SOFA score was 11.77±6.32 and 7.71±3.12. The overall CT scores of the patients was 247.68±34.28 and the range of CT scores was 196.3–294.7. The average MV days was 14.63±6.14, and 4 patients required additional rescue therapies for refractory hypoxemia. Despite these measures, 3 patients died.CONCLUSION: In H7 N9-infected patients with ARDS, low tidal volume strategy was the conventional mode. RM as one of rescue therapies to refractory hypoxemia in these patients with serious architectural distortion and high CT scores, which could cause further lung damage, may induce bad outcomes and requires serious consideration. Prone ventilation may improve mortality, and should be performed at the early stage of the disease, not as a rescue therapy.

New Bulb Turbine with Counter-rotating Tandem-runner

With the increasing demand for the clean sustainable power, the turbine design urgently turns to increase the capability significantly toward higher head for generating larger power. Currently, there are many studies in the field of the bulb turbine with single-stage runner, though reports about counter-rotating tandem-runner are rare. However, the further high-head application with the single-stage runner is very difficult to achieve due to the limit of the specific speed. In this paper, a new bulb turbine with the tandem-runner is designed in order to substantially increase the applicable limit toward higher head with larger power. A half of the net head is absorbed by the frontal runner which can generate output power, while the remaining half is absorbed by the rear runner. To generate the Euler energy required for the rear runner, the frontal runner has the counter-rotation against the rear runner so that the counter-rotating tandem-runner can meet the purpose of double head and power under the same size as the conventional bulb turbine. Supply and demand of Euler energy between the two runners are thoroughly optimized through the detailed flow analysis, in order to secure the stable operation. As a result, the interference of Euler energies between the outflow from the frontal runner and the inflow to the rear runner is confirmed to be very small on the counter-rotating interface between the two runners. The prediction method of on-cam performance between the two adjustable runners is also developed numerically, which provides optimal flow between the two runners. This research provides a theoretical basis for the optimal design and operation of the counter-rotating tandem-runner bulb turbines.

Subglottic Secretion Drainage for Preventing Ventilator Associated Pneumonia: A Meta-analysis

Objective： Ventilator associated pneumonia （VAP） has been shown to be associated with significant morbidity and mortality（ Chastre and Fagon, 2002; klompas, 2007） among mechanically venti- lated patients in the intensive care unit （ICU）, with the incidence ranging from 9% to 27% ; crude mortality ranges from 25% to 50%.1-3 A meta-analysis of published studies was undertaken to combine information regarding the effect of subglottic secretion drainage （SSD） on the incidence of ventilated associated pneumonia in adult ICU patients. Methods： Reports of studies on SSD were identified by searching the PUBMED, EMBASE, and COCHRANCE LIBRARY databases （December 30, 2010）. Randomized trials of SSD compared to usual care in adult mechanically ventilated ICU patients were included in this meta-analysis. Results： Ten RCTs with 2,314 patients were identified. SSD significantly reduced the incidence of VAP [ relative risk （RR） =0.52, 95% confidence interval （C/）： 0.42-0.64, P〈0.000 01]. When SSD was compared with the control groups, the overall RR for ICU mortality was 1.00 （95% CI, 0.84-1.19） and for hospital mortality was 0.95 （95% CI, 0. 80-1.13）. Overall, the subglottic drainage effect on the days of mechanical ventilation was -1.52 days （95% CI, -2.94 to -0.11） and on the ICU length of stay （LOS） was -0.81days （95% CI, -2.33 to -0.7）. Conclusions： In this meta-analysis, when an endotracheal tube （ETT） with SSD was compared with an ETT without SSD, there was a highly significant reduction in the VAP rate of approxi- mately 50%. Time on mechanical ventilation （MV） and the ICU LOS may be reduced, but no reduction in ICU or hospital mortality has been observed in published trials,

Modeling and Simulation of aCounter-Rotating Turbine System for Underwater Vehicles

The structure of a counter-rotating turbine of an underwater vehicle is designed by adding the counter-rotating second-stage turbine disk to the conventional single-stage turbine. The available kinetic energy and the absorption power of the auxiliary system are calculated at different working conditions, and the results show that the power of the main engine and auxiliary system at the counter-rotating turbine system matches well with each other. The technology scheme of the counter-rotating turbine system is proposed, then the experimental simulation of the lubricating oil loop, fuel loop, and seawater loop is completed. The simulation results indicate that the hydraulic transmission system can satisfy the requirements for an underwater vehicle running at a steady sailing or variable working conditions.

Expiratory flow-limitation in mechanically ventilated patients: A risk for ventilator-induced lung injury?

Expiratory flow limitation(EFL), that is the inability of expiratory flow to increase in spite of an increase of the driving pressure, is a common and unrecognized occurrence during mechanical ventilation in a variety of intensive care unit conditions. Recent evidence suggests that the presence of EFL is associated with an increase in mortality, at least in acute respiratory distress syndrome(ARDS) patients, and in pulmonary complications in patients undergoing surgery. EFL is a major cause of intrinsic positive end-expiratory pressure(PEEPi), which in ARDS patients is heterogeneously distributed, with a consequent increase of ventilation/perfusion mismatch and reduction of arterial oxygenation. Airway collapse is frequently concomitant to the presence of EFL.When airways close and reopen during tidal ventilation, abnormally high stresses are generated that can damage the bronchiolar epithelium and uncouple small airways from the alveolar septa, possibly generating the small airways abnormalities detected at autopsy in ARDS. Finally, the high stresses and airway distortion generated downstream the choke points may contribute to parenchymal injury, but this possibility is still unproven. PEEP application can abolish EFL, decrease PEEPi heterogeneity, and limit recruitment/derecruitment.Whether increasing PEEP up to EFL disappearance is a useful criterion for PEEP titration can only be determined by future studies.

Individualized Design of the Ventilator Mask based on the Residual Concentration of CO2

OSAHS(Obstructive Sleep Apnea Hypopnea Syndrome)is a respiratory disease mainly characterized by limited and repeated pauses of breathing in sleep.Currently,the optimal treatment is to apply CPAP(Continuous Positive Airway Pressure)ventilation on the upper airway of the patient through a household respiratory machine.However,if the ventilator mask is designed improperly,it might cause the residue and repeated inhalation of CO2,which will exert an adverse impact on the therapeutic effect.Present research numerically analyzed the CO2 transportation inside a commercial ventilator mask(Mirage SoftGel,ResMed,Australia)based on the reconstructed 3D numerical model of a volunteer's face and performed the improved design of the ventilator mask in terms of the CO2 residual concentration below the nostrils.The fluid dynamic analyses showed that at the end time of expiratory,the CO2 residual concentration below the nostrils is close to 4%.To improve the therapeutic effect,we changed the position of the exhaust holes and found that by moving the exhaust holes to the bottom of the ventilator mask,the CO2 residual concentration below the nostrils would be reduced to no more than 1%.This study established a near physiological computational model and provided a new method for the individualized design of the commercial ventilator mask.

Link Resource Allocation in Counter-Rotating Seam of Low-Orbit Satellite Network

This paper studies the communication problem at the counter-rotating seam of the low-orbit satellite based on the walker constellation. The counter-rotating seam has a short life cycle, low capacity, and dynamic geometric parameters. To better utilize the scarce link resources at the seam, increase network throughput, and approach the physical limits of the link throughput at the seam, an initial phase condition that maximizes the relative rotational joint link throughput is calculated. In the experimental simulation results using the Iridium system as an example, it is shown that better throughput can be obtained under the initial conditions, and the throughput is improved by about 30%.

Low-dose morphine elicits ventilatory excitant and depressant responses in conscious rats: Role of peripheral <i>µ</i>-opioid receptors

The systemic administration of morphine affects ventilation via a mixture of central and peripheral actions. The aims of this study were to characterize the ventilatory responses elicited by a low dose of morphine in conscious rats;to determine whether tolerance develops to these responses;and to determine the potential roles of peripheral μ-opioid receptors (μ-ORs) in these responses. Ventilatory parameters were monitored via unrestrained whole-body plethysmography. Conscious male Sprague-Dawley rats received an intravenous injection of vehicle or the peripherally-restricted μ-OR antagonist, naloxone methiodide (NLXmi), and then three successive injections of morphine (1 mg/kg) given 30 min apart. The first injection of morphine in vehicle-treated rats elicited an array of ventilatory excitant (i.e., increases in frequency of breathing, minute volume, respiratory drive, peak inspiratory and expiratory flows, accompanied by decreases in inspiratory time and end inspiratory pause) and inhibitory (i.e., a decrease in tidal volume and an increase in expiratory time) responses. Subsequent injections of morphine elicited progressively and substantially smaller responses. The pattern of ventilatory responses elicited by the first injection of morphine was substantially affected by pretreatment with NLXmi whereas NLXmi minimally affected the development of tolerance to these responses. Low-dose morphine elicits an array of ventilatory excitant and depressant effects in conscious rats that are subject to the development of tolerance. Many of these initial actions of morphine appear to involve activation of peripheral μ-ORs whereas the development of tolerance to these responses does not.

From hardware store to hospital:a COVID-19-inspired,cost-effective,open-source,in vivo-validated ventilator for use in resource-scarce regions

Resource-scarce regions with serious COVID-19 outbreaks do not have enough ventilators to support critically ill patients,and these shortages are especially devastating in developing countries.To help alleviate this strain,we have designed and tested the accessible low-barrier in vivo-validated economical ventilator(ALIVE Vent),a COVID-19-inspired,cost-effective,open-source,in vivo-validated solution made from commercially available components.The ALIVE Vent operates using compressed oxygen and air to drive inspiration,while two solenoid valves ensure one-way flow and precise cycle timing.The device was functionally tested and profiled using a variable resistance and compliance artificial lung and validated in anesthetized large animals.Our functional test results revealed its effective operation under a wide variety of ventilation conditions defined by the American Association of Respiratory Care guidelines for ventilator stockpiling.The large animal test showed that our ventilator performed similarly if not better than a standard ventilator in maintaining optimal ventilation status.The FiO2,respiratory rate,inspiratory to expiratory time ratio,positive-end expiratory pressure,and peak inspiratory pressure were successfully maintained within normal,clinically validated ranges,and the animals were recovered without any complications.In regions with limited access to ventilators,the ALIVE Vent can help alleviate shortages,and we have ensured that all used materials are publicly available.While this pandemic has elucidated enormous global inequalities in healthcare,innovative,cost-effective solutions aimed at reducing socio-economic barriers,such as the ALIVE Vent,can help enable access to prompt healthcare and life saving technology on a global scale and beyond COVID-19.

Selection of Heat Recovery Ventilators in Different Climate Zones of China

Considering four different climate zones in China, an investigation on the choice of heat recovery ventilator for the buildings with little moisture emissions is carried out. The annual composition of energy consumption of air intake for per unitary air ventilation flow rate is evaluated by employing the testing data of climatic parameters in eight selected cities. The analysis shows that the total heat recovery is suitable in a controlled ventilation system with air humidity controlled during heating period of all the climates. For the building without air humidity controlled in winter, the sensible heat recovery ventilators can be used in severe cold and cold regions, and total heat recovery systems are more suitable for energy saving in hot summer and cold winter and hot summer and warm winter regions.

Need for oxygen therapy and ventilatory support in premature infants in a hospital in Southern Brazil

BACKGROUND Prematurity in newborns is a condition that is associated with worse hospital outcomes when compared to birth to term.A preterm infant(PI)is classified when gestational age(GA)<37 wk.AIM To analyze prognostic indicators related to the use of oxygen therapy,noninvasive ventilation(continuous positive airway pressure)and mechanical ventilation(MV)in PI.METHODS This is a retrospective cohort.The sample was composed of PIs from a private hospital in southern Brazil.We included neonates with GA<37 wk of gestation in the period of January 1,2018 to December 31,2018.For data collection,electronic records were used in the Tasy Philips^(TM)system,identifying the variables:maternal age,type of birth,prenatal information,GA,Apgar score,birth weight,neonatal morbidities,vital signs in the 1st hour at birth,need for oxygen therapy,continuous positive airway pressure and MV,hospitalization in the neonatal intensive care unit,length of stay and discharge or death.RESULTS In total,90 PI records were analyzed.The median(p25-p75)of GA was 34.0(31.9-35.4)wk,and there were 45(50%)males.The most common morbidity among PIs was the acute respiratory discomfort syndrome,requiring hospitalization in the neonatal intensive care unit in 76(84.4%)cases.The utilization rate of oxygen therapy,continuous positive airway pressure and MV was 12(13.3%),37(41.1%)and 13(14.4%),respectively.The median(p25-p75)length of stay was 12.0(5.0-22.2)d,with 10(11.1%)deaths.A statistical association was observed with the use of MV and GA<28 wk,lower maternal age,low birth weight,Apgar<8 and neonatal deaths.CONCLUSION The identification of factors related to the need for MV in prematurity may help in the indication of a qualified team and technologies to promptly meet the unforeseen events that may occur after birth.