Dimensionless Study on Secretion Clearance of a Pressure Controlled Mechanical Ventilation System with Double Lungs

A pressure controlled mechanical ventilator with an automatic secretion clearance function can improve secretion clearance safely and efficiently.Studies on secretion clearance by pressure controlled systems show that these are suited for clinical applications.However,these studies are based on a single lung electric model and neglect the coupling between the two lungs.The research methods applied are too complex for the analysis of a multi-parameter system.In order to understand the functioning of the human respiratory system,this paper develops a dimensionless mathematical model of doublelung mechanical ventilation system with a secretion clearance function.An experiment is designed to verify the mathematical model through comparison of dimensionless experimental data and dimensionless simulation data.Finally,the coupling between the two lungs is studied,and an orthogonal experiment designed to identify the impact of each parameter on the system.

Modelling and Simulation of Pressure Controlled Mechanical Ventilation System

A mathematical model of mechanical ventilator describes its behavior during artificial ventilation. This paper purposes to create and simulate Mathematical Model (MM) of Pressure Controlled Ventilator (PCV) signal. This MM represents the respiratory activities and an important controlled parameter during mechanical ventilation—Positive End Expiration Pressure (PEEP). The MM is expressed and modelled using periodic functions with inequalities to control the beginning of inspiration and expiration durations. The created MM of PCV signal is combined with an existing multi compartmental model of respiratory system that is modified and developed in the internal parameters—compliances (C) to test created MM. The created MM and model of respiratory system are constructed and simulated using Simulink package in MATLAB platform. The obtained simulator of mechnical ventilation system could potentially represent the pressure signal of PVC as a complete respiratory cycle and continuance waveform. This simulator is also able to reflect a respiratory mechanic by changing some input variables such as inspiration pressure (IP), PEEP and C, which are monitored in volume, flow, pressure and PV loop waveforms. The obtained simulator has provided a simple environment for testing and monitoring PCV signal and other parameters (volume, flow and dynamic compliance) during artificial ventilation. Furthermore, the simulator may be used for studying in the laboratory and training ventilator’s operators.

Application of fiberoptic bronchscopy in patients with acute exacerbations of chronic obstructive pulmonary disease during sequential weaning of invasive-noninvasive mechanical ventilation

BACKGROUND:Early withdrawal of invasive mechanical ventilation(IMV) followed by noninvasive MV(NIMV) is a new strategy for changing modes of treatment in patients with acute exacerbations of chronic obstructive pulmonary disease(AECOPD) with acute respiratory failure(ARF).Using pulmonary infection control window(PIC window) as the switch point for transferring from invasive to noninvasive MV,the time for early extubation can be more accurately judged,and therapy efficacy can be improved.This study aimed to prospectively investigate the clinical effectiveness of fiberoptic bronchscopy(FOB) in patients with AECOPD during sequential weaning of invasive-noninvasive MV.METHODS:Since July 2006 to January 2011,106 AECOPD patients with ARF were treated with comprehensive medication and IMV after hospitalization.Patients were randomly divided into two groups according to whether fiberoptic bronchoscope is used(group A,n=54) or not(group B,n=52) during sequential weaning from invasive to noninvasive MV.In group A,for sputum suction and bronchoalveolar lavage(BAL),a fiberoptic bronchoscope was put into the airway from the outside of an endotracheal tube,which was accompanied with uninterrupted use of a ventilator.After achieving PIC window,patients of both groups changed to NIMV mode,and weaned from ventilation.The following listed indices were used to compare between the groups after treatment:1) the occurrence time of PIC,the duration of MV,the length of ICU stay,the success rate of weaning from MV for the first time,the rate of reventilatJon and the occurrence rate of ventilator-associated pneumonia(VAP);2) the convenience and safety of FOB manipulation.The results were compared using Student's f test and the Chi-square test.RESULTS:The occurrence time of PIC was(5.01 ±1.49) d,(5.87±1.87) d in groups A and B,respectively(P<0.05);the duration of MV was(6.98±1.84) d,(8.69±2.41) d in groups A and B,respectively(P<0.01);the length of ICU stay was(9.25±1.84) d,(11.10±2.63) d in groups A and B,respectively(P<0.01);the success rate of weaning for the first time was 96.30%,76.92%in groups A and B,respectively(P<0.01);the rate of reventilation was 5.56%,19.23%in groups A and B,respectively(P<0.05);and the occurrence rate of VAP was 3.70%,23.07%in groups A and B,respectively(P<0.01).Moreover,it was easy and safe to manipulate FOB,and no side effect was observed.CONCLUSIONS:The application of FOB in patients with AECOPD during sequential weaning of invasive-noninvasive MV is effective in ICU.It can decrease the duration of MV and the length of ICU stay,increase the success rate from weaning MV for the first time,reduce the rate of reventilation and the occurrence rate of VAP.In addition,such a method is convenient and safe in patients of this kind.

Theoretical modeling of airways pressure waveform for dual-controlled ventilation with physiological pattern and linear respiratory mechanics

The present paper describes the theoretical treatment performed for the geometrical optimization of advanced and improved-shape waveforms as airways pressure excitation for controlled breathings in dual-controlled ventilation applied to anaesthetized or severe brain injured patients, the respiratory mechanics of which can be assumed linear. Advanced means insensitive to patient breathing activity as well as to ventilator settings while improved-shape intends in comparison to conventional square waveform for a progressive approaching towards physiological transpulmonary pressure and respiratory airflow waveforms. Such functional features along with the best ventilation control for the specific therapeutic requirements of each patient can be achieved through the implementation of both diagnostic and compensation procedures effectively carried out by the Advance Lung Ventilation System (ALVS) already successfully tested for square waveform as airways pressure excitation. Triangular and trapezoidal waveforms have been considered as airways pressure excitation. The results shows that the latter fits completely the requirements for a physiological pattern of endoalveolar pressure and respiratory airflow waveforms, while the former exhibits a lower physiological behaviour but it is anyhow periodically recommended for performing adequately the powerful diagnostic procedure.

Harmonic excitation of linear respiratory mechanics for physiological dual controlled ventilation

The theoretical approach along with the rationale of harmonic excitation modality (HEM) applied as optimal dual controlled ventilation (DCV) to anaesthetized or severe brain injured patients, whose respiretory mechanics can be properly assumed steady and linear, are presented and discussed. The design criteria of an improved version of the Advanced Lung Ventilation System (ALVS), including HEM in its functional features, are described in details. In particular, the elimination of any undesiderable artificial distortion affecting the respiratory and ventilation pattern waveforms is achieved by maintaining continuous forever the airflow inside the ventilation circuit, ensuring also the highest level of safety for patient in any condition. In such a way, the full-time compatibility of controlled breathings with spontaneous breathing activity of patient during continuous positive airways pressure (CPAP) or bilevel positive airways pressure (BiPAP) ventilation modalities and during assisted/controlled ventilation(A/CV), includeing also synchronized or triggered ventilation modalities, is an intrinsic innovative feature of the system available for clinical application. As expected and according to the clinical requirements, HEM provides for physiological respiratory and ventilation pattern waveforms together with optimal “breath to breath” feedback control of lung volume driven by an improved diagnostic measurement procedure, whose outputs are also vital for adapting all the preset ventilation parameters to the current value of the respiratory parameters of patient. The results produced by software simulations concerning both adult and neonatal patients in different clinical conditions are completely consistent with those obtained by the theoretical treatment, showing that HEM reaches the best performances from both clinical and engineering points of view.

Effect of Rectus Plication during Abdominoplasty on the Mechanical Power and Airway Pressures: Comparison of Two Ventilatory Strategies

Background: Abdominoplasty is a commonly requested procedure for aesthetic improvement of the affected soft tissue layers of skin, fat, and muscle through the slightest incision feasible. The degree of plicature generates an increase in intraabdominal pressure that causes an increase in intrathoracic pressure. Pressure, volume, flow, and respiratory rate are components of a unique physical variable, the mechanical power (MP), and is an integrated variable linked to most factors related to postoperative pulmonary complications. Purpose: To assess the effect of rectus plication (RP) during abdominoplasty on lung pressures and the contribution to increasing the MP. Method: A open-label study was conducted at TJ Plast Advanced Center for Plastic Surgery in Tijuana, México, from September 2021 to May 2022. The study included forty-six female patients subjected to abdominoplasty or liposuction with abdominoplasty. After the induction of general anesthesia and neuromuscular blockade, they were allocated into two groups: Group 1 pressure control ventilation-volume guaranteed (PCV-VG) and Group 2 volume control ventilation (VCV). Respiratory pressures and MP were assessed before and after RP. Results: During VCV, patients had a greater increase in peak pressure (PIP) (P 0.000). Plateau pressure (Pplat) increased 1.78 ± 0.35 cmH2O in group 2 after RP (P = 0.001). MP had a greater increase in group 2 after RP (P 0.01). Conclusion: This prospective study showed that RP is related to an increase in PIP and Pplat and an increase in the MP better controlled with PCV-VG ventilation.

Altered diaphragmatic contractile properties after high airway pressure controlled mechanical ventilation

Acute respiratory failure is the most frequent indication for the application of mechanical ventilation. As commonly used in clinical settings, lung protective strategies and recruitment manoeuvres are applications of higher than normal airway pressure to open the collapsed alveoli and prevent lung atelectasis caused by minimal vital ventilation. Under those conditions, we pay more attention to the lung injury and circulatory failure,

Neural control of pressure support ventilation improved patient-ventilator synchrony in patients with different respiratory system mechanical properties:a prospective,crossover trial

Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing to an increased inspiratory effort.Using diaphragm electrical activity,neurally controlled pressure support(PSN)could hypothetically eliminate the asynchrony and reduce inspiratory effort.The purpose of this study was to compare the differences between PSN and PSP in terms of patient-ventilator synchrony,inspiratory effort,and breathing pattern.Methods:Eight post-operative patients without respiratory system comorbidity,eight patients with acute respiratory distress syndrome(ARDS)and obvious restrictive acute respiratory failure(ARF),and eight patients with chronic obstructive pulmonary disease(COPD)and mixed restrictive and obstructive ARF were enrolled.Patient-ventilator interactions were analyzed with macro asynchronies(ineffective,double,and auto triggering),micro asynchronies(inspiratory trigger delay,premature,and late cycling),and the total asynchrony index(AI).Inspiratory efforts for triggering and total inspiration were analyzed.Results:Total AI of PSN was consistently lower than that of PSP in COPD(3%vs.93%,P=0.012 for 100%support level;8%vs.104%,P=0.012 for 150%support level),ARDS(8%vs.29%,P=0.012 for 100%support level;16%vs.41%,P=0.017 for 150%support level),and post-operative patients(21%vs.35%,P=0.012 for 100%support level;15%vs.50%,P=0.017 for 150%support level).Improved support levels from 100%to 150%statistically increased total AI during PSP but not during PSN in patients with COPD or ARDS.Patients’inspiratory efforts for triggering and total inspiration were significantly lower during PSN than during PSP in patients with COPD or ARDS under both support levels(P<0.05).There was no difference in breathing patterns between PSN and PSP.Conclusions:PSN improves patient-ventilator synchrony and generates a respiratory pattern similar to PSP independently of any level of support in patients with different respiratory system mechanical properties.PSN,which reduces the trigger and total patient’s inspiratory effort in patients with COPD or ARDS,might be an alternative mode for PSP.Trial Registration:ClinicalTrials.gov,NCT01979627;https://clinicaltrials.gov/ct2/show/record/NCT01979627.

Sequential non-invasive mechanical ventilation following short-term invasive mechanical ventilation in COPD induced hypercapnic respiratory failure

Objective To estimate the feasibility and the efficacy of early extubation and sequential non-invasive mechanical ventilation (MV) in chronic obstructive pulmonary disease (COPD) with exacerbated hypercapnic respiratory failure.Methods Twenty-two intubated COPD patients with severe hypercapnic respiratory failure due to pulmonary infection (pneumonia or purulent bronchitis) were involved in the study. At the time of pulmonary infection control window (PIC window) appeared, when pulmonary infection had been significantly controlled (resolution of fever and decrease in purulent sputum, radiographic infiltrations, and leukocytosis) after the antibiotic and the comprehensive therapy, the early extubation was conducted and followed by non-invasive MV via facial mask immediately in 11 cases (study group). Other 11 COPD cases with similar clinical characteristics who continuously received invasive MV after PIC window were recruited as control group.Results All patients had similar clinical characteristics and gas exchange before treatment, as well as the initiating time and all indices at the time of the PIC window. For study group and control group, the duration of invasive MV was (7.1±2.9) vs (23.0±14.0) days, respectively, P<0.01. The total duration of ventilatory support was (13±7) vs (23±14) days, respectively, P<0.05. The incidence of ventilator associated pneumonia (VAP) were 0/11 vs 6/11, respectively, P<0.01. The duration of intensive care unit (ICU) stay was (13±7) vs (26±14) days, respectively, P<0.05. Conclusions In COPD patients requiring intubation and MV for pulmonary infection and hypercapnic respiratory failure, early extubation followed by non-invasive MV initiated at the point of PIC window significantly decreases the invasive and total durations of ventilatory support, the risk of VAP, and the duration of ICU stay.

Non-invasive versus invasive mechanical ventilation for respiratory failure in severe acute respiratory syndrome

Background Severe acute respiratory syndrome is frequently complicated by respiratory failure requiring ventilatory support.We aimed to compare the efficacy of non-invasive ventilation against invasive mechanical ventilation treating respiratory failure in this disease.Methods Retrospective analysis was conducted on all respiratory failure patients identified from the Hong Kong Hospital Authority Severe Acute Respiratory Syndrome Database.Intubation rate,mortality and secondary outcome of a hospital utilizing non-invasive ventilation under standard infection control conditions(NIV Hospita1)were compared against 13 hospitals using solely invasive ventilation(IMV Hospitals).Multiple logistic regression analyses with adjustments for confounding variables were performed to test for association between outcomes and hospital groups.Results Both hospital groups had comparable demographics and clinical profiles,but NIV Hospital(42 patients)had higher lactate dehydrogenase ratio and worse radiographic score on admission and ribavirin-corticosteroid commencement.Compared to IMV Hospitals(451 patients).NIV Hospital had lower adjusted odds ratios for intubation(0.36,95%C10.164-0.791,P=0.011)and death(0.235.95%C10.077-0.716,P=0.O 11),and improved earlier after pulsed steroid rescue.There were no instances of transmission of severe acute respiratory syndrome among health care workers due to the use of non-invasive ventilation.Conclusion Compared to invasive mechanical ventilation,non-invasive ventilation as initial ventilatory support for acute respiratory failure in the presence of severe acute respiratory syndrome appeared to be associated with reduced intubation need and mortality.

Comparative efficacy of honey 12.5% and chlorhexidine 0.2% mouthwashes on the oropharyngeal bacterial colonization in mechanically-ventilated patients: a randomized controlled trial

OBJECTIVE: To compare the efficacy of honey mouthwash 12.5% and chlorhexidine solution 0.2%to reduce the rate of oropharyngeal bacterial colonization in mechanically-ventilated patients.METHODS: This study was a randomized, single blind, phase Ⅲ controlled clinical trial. Sixty patients newly admitted to internal and trauma Intensive Care Units of the two educational hospitals of Sanandaj city affiliated with Kurdistan University of Medical Sciences were selected by convenience sampling and allocated to two groups of 30 patients using random blocks design. In each group,the mouthwash was applied twice a day for four consecutive days. Swab samples were taken from the mouth and throat of all patients three times a day(pre-intervention, two days, and four days after the intervention) and then the samples were transferred onto the blood agar and eosin methylene blue(EMB) culture plates and investigated for bacterial growth and colonization after 24-48 h.RESULTS: The findings showed that oropharyngeal colonization was not significantly different between the two groups, pre-intervention, two days,and four days after the intervention(P > 0.05). Rinsing with honey mouthwash 12.5% led to the inhibition of Staphylococcus aureus and Pseudomonas aeruginosa on the fourth day of the intervention in all samples.CONCLUSION: None of the studied solutions contributed to the reduction of oropharyngeal bacterial colonization. It seems that the growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa by the honey 12.5% mouthwash in mechanically-ventilated patients need further investigation.

Mechanical ventilation strategy for pulmonary rehabilitation based on patient-ventilator interaction

Mechanical ventilation is an effective medical means in the treatment of patients with critically ill,COVID-19 and other pulmonary diseases.During the mechanical ventilation and the weaning process,the conduct of pulmonary rehabilitation is essential for the patients to improve the spontaneous breathing ability and to avoid the weakness of respiratory muscles and other pulmonary functional trauma.However,inappropriate mechanical ventilation strategies for pulmonary rehabilitation often result in weaning difficulties and other ventilator complications.In this article,the mechanical ventilation strategies for pulmonary rehabilitation are studied based on the analysis of patient-ventilator interaction.A pneumatic model of the mechanical ventilation system is established to determine the mathematical relationship among the pressure,the volumetric flow,and the tidal volume.Each ventilation cycle is divided into four phases according to the different respiratory characteristics of patients,namely,the triggering phase,the inhalation phase,the switching phase,and the exhalation phase.The control parameters of the ventilator are adjusted by analyzing the interaction between the patient and the ventilator at different phases.A novel fuzzy control method of the ventilator support pressure is proposed in the pressure support ventilation mode.According to the fuzzy rules in this research,the plateau pressure can be obtained by the trigger sensitivity and the patient’s inspiratory effort.An experiment prototype of the ventilator is established to verify the accuracy of the pneumatic model and the validity of the mechanical ventilation strategies proposed in this article.In addition,through the discussion of the patient-ventilator asynchrony,the strategies for mechanical ventilation can be adjusted accordingly.The results of this research are meaningful for the clinical operation of mechanical ventilation.Besides,these results provide a theoretical basis for the future research on the intelligent control of ventilator and the automation of weaning process.

Efficacy and safety of ivermectin in patients with mild and moderate COVID-19:A randomized controlled trial

Objective:To evaluate the effectiveness and safety of ivermectin in patients with mild and moderate COVID-19.Methods:This study was a single-center,randomized,open-label,controlled trial with a 2-arm parallel-group design on 68 patients with COVID-19.According to the 1:1 ratio between the study groups(ivermectin group and standard treatment group),patients were randomly admitted to each intervention arm.Results:The mean age of the participants in the ivermectin group was(48.37±13.32)years.Eighteen of them were males(54.5%)and the participants in the control group had a mean age of(46.28±14.47)years,with nineteen of them being males(59.4%).As a primary outcome,after 5 days of randomization,there was no significant difference between the ivermectin group and the control group in the length of stay in the hospital(P=0.168).ICU admission(P=0.764),length of stay in ICU(P=0.622),in-hospital mortality(P=0.427),adverse drug reactions,and changes in the mean difference of laboratory data had not any significant difference between the two groups(except for urea change).In addition,the radiologic findings of the two groups of patients were not significantly different.Linear regression analysis showed that for every 10 years increase of age,0.6 day of hospitalization duration was increased.There was no statistically significant association between other variables and clinical outcomes.Conclusions:Among adult hospitalized patients with moderate to severe COVID-19,there was no significant relationship between the administration of ivermectin single dose in a five-day course and clinical improvement,and mortality of the participants.

Artificial intelligence for closed-loop ventilation therapy with hemodynamic control using the open lung concept

Purpose–The purpose of this paper is to develop an automatic control system for mechanical ventilation therapy based on the open lung concept(OLC)using artificial intelligence.In addition,mean arterial blood pressure(MAP)is stabilized by means of a decoupling controller with automated noradrenaline(NA)dosage to ensure adequate systemic perfusion during ventilation therapy for patients with acute respiratory distress syndrome(ARDS).Design/methodology/approach–The aim is to develop an automatic control system for mechanical ventilation therapy based on the OLC using artificial intelligence.In addition,MAP is stabilized by means of a decoupling controller with automated NA dosage to ensure adequate systemic perfusion during ventilation therapy for patients with ARDS.Findings–Thisinnovativeclosed-loop mechanicalventilation system leadsto a significant improvement in oxygenation,regulates end-tidal carbon dioxide for appropriate gas exchange and stabilizes MAP to guarantee proper systemic perfusion during the ventilation therapy.Research limitations/implications–Currently,this automatic ventilation system based on the OLC can only be applied in animal trials;for clinical use,such a system generally requires a mechanical ventilator and sensors with medical approval for humans.Practical implications–For implementation of a closed-loop ventilation system,reliable signals from the sensors are a prerequisite for successful application.Originality/value–Theexperiment with porcine dynamics demonstrates thefeasibility and usefulness of this automatic closed-loop ventilation therapy,with hemodynamic control for severe ARDS.Moreover,this pilot study validated a new algorithm for implementation of the OLC,whereby all control objectives are fulfilled during the ventilation therapy with adequate hemodynamic control of patients with ARDS.

综掘工作面混合式风流调控下的粉尘沉降研究

煤矿掘进过程中粉尘聚集严重,目前针对综掘工作面混合式风流调控下粉尘沉降规律及优化的研究还不够深入。基于混合式风流调控系统,依托陕煤集团神木柠条塔矿业有限公司综掘工作面,分析了压风口距工作面距离、压风口右偏角度、压风口口径、抽风口距工作面距离和压抽比等混合式风流调控参数对粉尘沉降规律的影响:随着压风口距工作面距离增加,司机处和回风侧行人呼吸带截面大颗粒粉尘占比先增后减再增,小颗粒粉尘占比增加;随着压风口右偏角度增加,司机处和回风侧行人呼吸带截面大颗粒粉尘占比变化明显;随着压风口口径增加,司机处截面小颗粒粉尘占比先增后减再增,回风侧行人呼吸带截面大颗粒粉尘占比先增后减;随着抽风口距工作面距离增加,司机处截面大颗粒粉尘占比先增后减,小颗粒粉尘占比先增后减再增,回风侧行人呼吸带截面粉尘粒径分布变化不大;随着压抽比增大,司机处和回风侧行人呼吸带截面小颗粒粉尘占比减小。以上述风流调控各参数为自变量,回风侧行人呼吸带全尘平均浓度和司机处呼尘平均浓度最低为优化目标,建立了粉尘沉降优化回归模型,利用粒子群优化算法求解模型,得到最优风流调控方案:压风口距工作面距离为8.9 m,压风口右偏角度为14.8°,压风口口径为0.9 m,抽风口距工作面距离为4.3 m,压抽比为1.1。搭建了风流调控下粉尘沉降实验平台,实验结果表明:测试值与粉尘沉降优化回归模型的模拟值误差在13%以内,验证了模型的准确性;优化后粒径为71~100μm的粉尘受风流调控参数影响明显,沉降在掘进机前方;优化后回风侧行人呼吸带全尘平均浓度和司机处呼尘平均浓度分别降低了47.4%和42.4%,降尘效果明显。

扁平大空间船舶火灾烟气控制试验研究

为有效控制扁平大空间船舶火灾烟气蔓延,研究大尺度火灾过程中的油池质量损失速率、舱室温度分布、隔热效率和烟气控制效果。利用尺寸为30 m×24 m×2.3 m的模拟舱,在0.35、0.55和0.70 m等3种不同挡烟垂壁高度和机械通风条件下开展试验。结果表明:挡烟垂壁高度增加,油池质量损失速率峰值减小;挡烟垂壁高度对舱室上层烟气温度的影响比对下层气体温度的影响更明显,1.4 m以上空间温度峰值明显下降,而1.4 m以下空间温度峰值无明显变化。顶棚平均温度和隔热效率随挡烟垂壁高度增加而下降。随挡烟垂壁高度增加,火源区与非火源区同时控烟模式隔热效率从28.2%提升至50.8%,火源区单独控烟模式隔热效率从29.4%提升至54.7%。

持续腹内压监测联合前馈控制理论在机械通气患者早期肠内营养耐受性评估中的临床应用

目的 通过随机试验设计,探究持续腹内压监测联合前馈控制理论在提升机械通气患者早期肠内营养耐受性方面的效果。方法 本研究共纳入2022年6月至2023年6月在三明市第二医院就诊的机械通气患者100例,将机械通气患者随机分为两组,每组各50例,对照组采用常规肠内营养支持,试验组则在此基础上引入持续腹内压监测与前馈控制理论。观察两组患者的机械通气时间与住院时间、干预后第1、3、7、14天的腹内压变化情况、营养状态指标、营养风险筛查2002(NRS2002)评分以及肠内营养的耐受性情况。结果 试验组机械通气时间和住院时间均显著短于对照组,差异有统计学意义(P <0.05)。干预后第7、14天,试验组腹内压显著低于对照组,差异有统计学意义(P <0.05)。干预后第14天,试验组血清前白蛋白、血清白蛋白以及血红蛋白水平均显著高于对照组,差异有统计学意义(P <0.05)。干预后第14天,试验组NRS2002评分显著低于对照组,差异有统计学意义(P <0.05)。试验组良好耐受比例显著高于对照组,而中等耐受和不耐受比例均显著低于对照组,差异有统计学意义(P <0.05)。结论 结合持续的腹内压监测和前馈控制理论,可以显著提高机械通气患者在早期对肠内营养的耐受性,优化患者营养状态并减少营养缺乏的风险,这种方法在临床实践中具有广泛的应用价值。

深井矿山热害防治及制冷降温技术应用

随着金属矿山开采深度的增加,高地温越加显现,而矿山在热害控制方面经验不足、个体防护及培训缺失、有效的机械制冷技术应用较少等,亟待加强深井金属矿山热害防治安全技术相关研究。本文分析了深井矿山热环境对作业人员、生产效率的影响,总结了热害防治的综合措施,包括通风系统优化、热源控制、个体防护、压缩空气制冷、机械制冷等方面,列举了南非、澳大利亚两座典型深井矿山机械制冷降温技术的典型应用,供其他深井矿山借鉴。

不同机械通气模式在胸外按压联合机械通气救治过程中的应用效果

目的:探究不同机械通气模式在胸外按压联合机械通气救治过程中的应用效果。方法:选择2022年1月—2023年7月华南理工大学附属第六医院收治的100例心搏骤停应用胸外按压联合机械通气救治患者作为研究对象,按照机械通气模式将其分为对照组和观察组,各50例。对照组采用容量控制模式(capacity control mode,V-A/C),观察组压力支持通气(pressure support ventilation,PSV),比较两组潮气量、分钟通气量、氧合指数、二氧化碳分压(partial pressure of carbon dioxide,PCO_(2))、氧分压(oxygen partial pressure,PO_(2))、昏迷指数评分、抢救结果。结果:观察组潮气量、分钟通气量高于对照组,差异有统计学意义(P<0.05);观察组通气0.5 h、1.0 h、2.0 h后氧合指数高于对照组,差异有统计学意义(P<0.05);观察组通气0.5 h、1.0 h、2.0 h后PCO_(2)低于对照组,PO_(2)高于对照组,差异有统计学意义(P<0.05);通气24 h后,两组睁眼反应、肢体运动评分提高,且观察组高于对照组,差异有统计学意义(P<0.05);观察组通气2 h后抢救成功率高于对照组,差异有统计学意义(P<0.05)。结论:V-A/C、PSV在胸外按压联合机械通气救治过程中均能获得良好的效果,但V-A/C可提高潮气量、分钟通气量、氧合指数、PO_(2)、昏迷指数、抢救成功率。

PLC电气控制系统在煤炭开采中的应用分析

主要对PLC电气控制系统在煤炭开采中的应用进行了分析。通过介绍PLC技术和煤炭开采领域的需求,探讨了PLC电气控制系统在煤炭开采过程中的具体应用,包括采矿机械设备控制、安全监测与报警系统、矿井通风系统控制等方面。研究表明,PLC电气控制系统在煤炭开采中具有显著的优势,能够提高生产效率和增强安全性能。最后总结了PLC电气控制系统在煤炭开采中的应用效果,并提出了其未来的发展方向。