Driving pressure in mechanical ventilation:A review

Driving pressure(ΔP)is a core therapeutic component of mechanical ventilation(MV).Varying levels ofΔP have been employed during MV depending on the type of underlying pathology and severity of injury.However,ΔP levels have also been shown to closely impact hard endpoints such as mortality.Considering this,conducting an in-depth review ofΔP as a unique,outcome-impacting therapeutic modality is extremely important.There is a need to understand the subtleties involved in making sureΔP levels are optimized to enhance outcomes and minimize harm.We performed this narrative review to further explore the various uses ofΔP,the different parameters that can affect its use,and how outcomes vary in different patient populations at different pressure levels.To better utilizeΔP in MV-requiring patients,additional large-scale clinical studies are needed.

Brain protective effect of dexmedetomidine vs propofol for sedation during prolonged mechanical ventilation in non-brain injured patients

BACKGROUND Dexmedetomidine and propofol are two sedatives used for long-term sedation.It remains unclear whether dexmedetomidine provides superior cerebral protection for patients undergoing long-term mechanical ventilation.AIM To compare the neuroprotective effects of dexmedetomidine and propofol for sedation during prolonged mechanical ventilation in patients without brain injury.METHODS Patients who underwent mechanical ventilation for>72 h were randomly assigned to receive sedation with dexmedetomidine or propofol.The Richmond Agitation and Sedation Scale(RASS)was used to evaluate sedation effects,with a target range of-3 to 0.The primary outcomes were serum levels of S100-βand neuron-specific enolase(NSE)every 24 h.The secondary outcomes were remifentanil dosage,the proportion of patients requiring rescue sedation,and the time and frequency of RASS scores within the target range.RESULTS A total of 52 and 63 patients were allocated to the dexmedetomidine group and propofol group,respectively.Baseline data were comparable between groups.No significant differences were identified between groups within the median duration of study drug infusion[52.0(IQR:36.0-73.5)h vs 53.0(IQR:37.0-72.0)h,P=0.958],the median dose of remifentanil[4.5(IQR:4.0-5.0)μg/kg/h vs 4.6(IQR:4.0-5.0)μg/kg/h,P=0.395],the median percentage of time in the target RASS range without rescue sedation[85.6%(IQR:65.8%-96.6%)vs 86.7%(IQR:72.3%-95.3),P=0.592],and the median frequency within the target RASS range without rescue sedation[72.2%(60.8%-91.7%)vs 73.3%(60.0%-100.0%),P=0.880].The proportion of patients in the dexmedetomidine group who required rescue sedation was higher than in the propofol group with statistical significance(69.2%vs 50.8%,P=0.045).Serum S100-βand NSE levels in the propofol group were higher than in the dexmedetomidine group with statistical significance during the first six and five days of mechanical ventilation,respectively(all P<0.05).CONCLUSION Dexmedetomidine demonstrated stronger protective effects on the brain compared to propofol for long-term mechanical ventilation in patients without brain injury.

Predictive value of diaphragm ultrasound for mechanical ventilation outcome in patients with acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND Acute exacerbation of chronic obstructive pulmonary disease(AECOPD)is often combined with respiratory failure,which increases the patient's morbidity and mortality.Diaphragm ultrasound(DUS)has developed rapidly in the field of critical care in recent years.Studies with DUS monitoring diaphragm-related rapid shallow breathing index have demonstrated important results in guiding intensive care unit patients out of the ventilator.Early prediction of the indications for withdrawal of non-invasive ventilator and early evaluation of patients to avoid or reduce disease progression are very important.AIM To explore the predictive value of DUS indexes for non-invasive ventilation outcome in patients with AECOPD.METHODS Ninety-four patients with AECOPD who received mechanical ventilation in our hospital from January 2022 to December 2023 were retrospectively analyzed,and they were divided into a successful ventilation group(68 cases)and a failed ventilation group(26 cases)according to the outcome of ventilation.The clinical data of patients with successful and failed noninvasive ventilation were compared,and the independent predictors of noninvasive ventilation outcomes in AECOPD patients were identified by multivariate logistic regression analysis.RESULTS There were no significant differences in gender,age,body mass index,complications,systolic pressure,heart rate,mean arterial pressure,respiratory rate,oxygen saturation,partial pressure of oxygen,oxygenation index,or time of inspiration between patients with successful and failed mechanical ventilation(P>0.05).The patients with successful noninvasive ventilation had shorter hospital stays and lower partial pressure of carbon dioxide(PaCO_(2))than those with failed treatment,while potential of hydrogen(pH),diaphragm thickening fraction(DTF),diaphragm activity,and diaphragm movement time were significantly higher than those with failed treatment(P<0.05).pH[odds ratio(OR)=0.005,P<0.05],PaCO_(2)(OR=0.430,P<0.05),and DTF(OR=0.570,P<0.05)were identified to be independent factors influencing the outcome of mechanical ventilation in AECOPD patients.CONCLUSION The DUS index DTF can better predict the outcome of non-invasive ventilation in AECOPD patients.

Impact of Sedation Protocols on Elderly Patients Undergoing Mechanical Ventilation and Off-Line Weaning

The proportion of elderly patients in intensive care is increasing, and a significant proportion of them require mechanical ventilation. How to implement safe and effective mechanical ventilation for elderly patients, and when appropriate off-line is an important issue in the field of critical care medicine. Appropriate sedation can improve patient outcomes, but excessive sedation may lead to prolonged mechanical ventilation and increase the risk of complications. Elderly patients should be closely monitored and evaluated on an individual basis while offline, and the sedation regimen should be dynamically adjusted. This requires the healthcare team to consider the patient’s sedation needs, disease status, and pharmacodynamics and pharmacokinetics of the drug to arrive at the best strategy. Although the current research has provided valuable insights and strategies for sedation and off-line management, there are still many problems to be further explored and solved.

Effect of different ventilation methods combined with pulmonary surfactant on neonatal acute respiratory distress syndrome

BACKGROUND Acute respiratory distress syndrome precipitates is widespread pulmonary injury in impacted individuals,the neonatal respiratory distress syndrome(NRDS),primarily observed in preterm infants,represents a prevalent critical condition in neonatal clinical settings.AIM To investigate the clinical efficacy of various ventilation strategies combined with pulmonary surfactant(PS)therapy in the treatment of NRDS.METHODS A total of 20 neonates diagnosed with respiratory distress syndrome,admitted between May 2021 and June 2022,were randomly assigned to either a research group or a control group.Neonates in the research group received treatment involving high-frequency oscillatory ventilation(HFOV)in conjunction with PS.In contrast,neonates in the control group were administered either controlled mechanical ventilation or synchronous intermittent mandatory ventilation,combined with PS.Arterial blood samples from the neonates in both groups were collected before treatment,as well as 6 h,12 h,24 h,and 48 h post-treatment.These samples underwent blood gas analysis,with measurements taken for pH value,partial pressures of oxygen(O_(2))and carbon dioxide.Concurrently,data was collected on the duration of ventilator use,length of hospitalization time,O_(2) treatment time,treatment outcomes,and complications of the ventilator.RESULTS From 6-48 h post-treatment,both groups demonstrated significant improvements in arterial blood pH and oxygen partial pressure,along with a significant decrease in carbon dioxide partial pressure compared to pre-treatment values(P<0.05).Although these changes progressed over time,there were no significant differences between the two groups(P>0.05).However,the research group had significantly lower X-ray scores,shorter hospitalization time,and less time on O_(2) therapy compared to the control group(P<0.05).Mortality rates were similar between the two groups(P>0.05),but the research group had a significantly lower incidence of complications(P<0.05).CONCLUSION The integration of HFOV combine with PS has proven to effectively expedite the treatment duration,decrease the occurrence of complications,and secure the therapeutic efficacy in managing NRDS.

Use of inflammatory markers as predictor for mechanical ventilation in COVID-19 patients with stagesⅢb-Ⅴchronic kidney disease?

BACKGROUND Studies have shown elevated C-reactive protein(CRP)to predict mechanical ventilation(MV)in patients with coronavirus disease 2019(COVID-19).Its utility is unknown in patients with chronic kidney disease(CKD),who have elevated baseline CRP levels due to chronic inflammation and reduced renal clearance.AIM To assess whether an association exists between elevated inflammatory markers and MV rate in patients with stagesⅢb-ⅤCKD and COVID-19.METHODS We conducted a retrospective cohort study on patients with COVID-19 and stagesⅢb-ⅤCKD.The primary outcome was the rate of invasive MV,the rate of noninvasive MV,and the rate of no MV.Statistical analyses used unpaired t-test for continuous variables and chi-square analysis for categorical variables.Cutoffs for variables were CRP:100 mg/L,ferritin:530 ng/mL,D-dimer:0.5 mg/L,and lactate dehydrogenase(LDH):590 U/L.RESULTS 290 were screened,and 118 met the inclusion criteria.CRP,D-dimer,and ferritin were significantly different among the three groups.On univariate analysis for invasive MV(IMV),CRP had an odds ratio(OR)-5.44;ferritin,OR-2.8;LDH,OR-7.7;D-dimer,OR-3.9,(P<0.05).The admission CRP level had an area under curve-receiver operator characteristic(AUROC):0.747 for the IMV group(sensitivity-80.8%,specificity-50%)and 0.663 for the non-IMV(NIMV)group(area under the curve,sensitivity-69.2%,specificity-53%).CONCLUSION Our results demonstrate a positive correlation between CRP,ferritin,and D-dimer levels and MV and NIMV rates in CKD patients.The AUROC demonstrates a good sensitivity for CRP levels in detecting the need for MV in patients with stagesⅢb-ⅤCKD.This may be because of the greater magnitude of increased inflammation due to COVID-19 itself compared with increased inflammation and reduced clearance due to CKD alone.

Clinical evaluation of ventilation mode on acute exacerbation of chronic obstructive pulmonary disease with respiratory failure

BACKGROUND At present,understanding of the most effective ventilation methods for treating chronic obstructive pulmonary disease(COPD)patients experiencing acute worsening symptoms and respiratory failure remains relatively limited.This report analyzed the efficiency and side effects of various ventilation techniques used for individuals experiencing an acute COPD exacerbation.AIM To determine whether pressure-controlled ventilation(PCV)can lower peak airway pressures(PAPs)and reduce the incidence of barotrauma compared to volume-controlled ventilation(VCV),without compromising clinical outcomes and oxygenation parameters.METHODS We have evaluated 600 patients who were hospitalized due to a severe COPD exacerbation,with 400 receiving mechanical ventilation for the respiratory failure.The participants were divided into two different groups,who were administered either VCV or PCV,along with appropriate management.We thereafter observed patients'attributes,clinical factors,and laboratory,radiographic,and arterial blood gas evaluations at the start and during their stay in the intensive care unit(ICU).We have also employed appropriate statistical methods for the data analysis.RESULTS Both the VCV and PCV groups experienced significant enhancements in the respiratory rate,tidal volume,and arterial blood gas values during their time in the ICU.However,no significant distinctions were detected between the groups in terms of oxygenation indices(partial pressures of oxygen/raction of inspired oxygen ratio)and partial pressures of carbon dioxide improvements.There was no considerable disparity observed between the VCV and PCV groups in the hospital mortality(32%vs 28%,P=0.53),the number of days of ICU stay[median interquartile range(IQR):9(6-14)d vs 8(5-13)d,P=0.41],or the duration of the mechanical ventilation[median(IQR):6(4-10)d vs 5(3-9)d,P=0.47].The PCV group displayed lower PAPs compared to the VCV group(P<0.05)from the beginning of mechanical ventilation until extubation or ICU departure.The occurrence of barotrauma was considerably lower in the PCV group in comparison to the VCV group(6%vs 16%,P=0.03).CONCLUSION Both VCV and PCV were found to be effective in treating patients with acute COPD exacerbation.However,PCV was associated with lower PAPs and a significant decrease in barotrauma,thus indicating that it might be a safer ventilation method for this group of patients.However,further large-scale study is necessary to confirm these findings and to identify the best ventilation approach for patients experiencing an acute COPD exacerbation.

Effects of ultrasound monitoring of gastric residual volume on feeding complications,caloric intake and prognosis of patients with severe mechanical ventilation

BACKGROUND Monitoring of gastric residual is an important approach for assessing gastric emptying in patients with mechanical ventilation.By monitoring gastric contents,the enteral nutrition scheme can be adjusted in time to ensure feeding safety.AIM To investigate the effects of ultrasound monitoring on the incidence of feeding complications,daily caloric intake and prognosis of patients with severe mechanical ventilation.To analyze the clinical significance of ultrasound monitoring of gastric residual volume(GRV)up to 250 mL to provide a theoretical basis for clinical practice.METHODS Patients admitted to the department of emergency medicine of the Affiliated Hospital of Nantong University from January 2018 to June 2022 who received invasive mechanical ventilation and continuous enteral nutrition support within 24-48 h after admission were enrolled in this study.Medical records for patients within 7 d of hospitalization were retrospectively analyzed to compare the incidence of feeding complications,daily caloric intake and clinical prognosis between patients with gastric residual≥250 mL and<250 mL,as monitored by ultrasound on the third day.RESULTS A total of 513 patients were enrolled in this study.Incidences of abdominal distension,diarrhea,and vomiting in the<250 mL and≥250 mL groups were:18.4%vs 21.0%,23.9%vs 32.3%and 4.0%vs 6.5%,respectively;mortality rates were 20.8%vs 22.65%;mechanical ventilation durations were 18.30 d vs 17.56 d while lengths of stay in the intensive care units(ICU)were 19.87 d vs 19.19±5.19 d.Differences in the above factors between groups were not significant.Gastric residual≥250 mL was not an independent risk factor for death and prolonged ICU stay.However,target feeding time of patients in the≥250 mL group was longer than that of patients in the≥250 mL group,and caloric intake(22.0,23.6,24.8,25.3 kcal/kg/d)for patients in the≥250 mL group from the 4^(th) day to the 7^(th) day of hospitalization was lower than that of patients in the≥250 mL group(23.2,24.8,25.7,25.8 kcal/kg/d).On the 4^(th) day(Z=4.324,P=0.013),on the 5^(th) day(Z=3.376,P=0.033),while on the 6^(th) day(Z=3.098,P=0.04),the differences were statistically significant.CONCLUSION The use of ultrasound to monitor GRV and undertaking clinical interventions when the monitoring value is≥250 mL has no significant effects on incidences of feeding complications and clinical prognostic outcomes,however,it significantly prolongs the time to reach target feeding,reduces the daily intake of calories during ICU hospitalization,and increases the risk of insufficient nutrition of patients.The accuracy and necessity of monitoring gastric remnants and monitoring frequencies should be investigated further.

Effect of early stepwise cardiopulmonary rehabilitation on function and quality of life in sepsis patients

BACKGROUND Sepsis,as a non-limiting host infection disease,can be accompanied by serious complications such as organ failure,which seriously threatens patient quality of life.AIM To investigate the effect of early stepwise cardiopulmonary rehabilitation on cardiopulmonary function and quality of life in patients evacuated from mechanical ventilation with sepsis.METHODS A total of 80 patients with sepsis who were hospitalized in our hospital from January 2021 to January 2022 were selected and divided into the observation group(n=40)and the control group(n=40)according to the random number table method.The observation group was treated with early stepwise cardiopulmonary rehabilitation,and the control group was treated with a conventional treatment regimen.Cardiac function indexes(central venous pressure,cardiac troponin I,B-type brain natriuretic peptide),lung function indicators(diaphragmatic mobility,changes in central venous oxygen saturation,oxygenation index),and quality of life(Quality of Life Evaluation Scale)were compared between the two groups after treatment.RESULTS After treatment,the central venous pressure,diaphragm mobility,central venous oxygen saturation,oxygenation index,and Quality of Life Evaluation Scale scores in the observation group were higher than those in the control group,and the differences were statistically significant(P<0.05).The observation group was less than that of the control group for other parameters,and the differences were statistically significant(P<0.05).CONCLUSION Early stepwise cardiopulmonary rehabilitation can effectively enhance cardiac and pulmonary function and improve the quality of life in patients evacuated from mechanical ventilation with sepsis.

Inhaled volatile anesthetics in the intensive care unit

The discovery and utilization of volatile anesthetics has significantly transformed surgical practices since their inception in the mid-19th century.Recently,a paradigm shift is observed as volatile anesthetics extend beyond traditional confines of the operating theatres,finding diverse applications in intensive care settings.In the dynamic landscape of intensive care,volatile anesthetics emerge as a promising avenue for addressing complex sedation requirements,managing refractory lung pathologies including acute respiratory distress syndrome and status asthmaticus,conditions of high sedative requirements including burns,high opioid or alcohol use and neurological conditions such as status epilepticus.Volatile anesthetics can be administered through either inhaled route via anesthetic machines/devices or through extracorporeal membrane oxygenation circuitry,providing intensivists with multiple options to tailor therapy.Furthermore,their unique pharmacokinetic profiles render them titratable and empower clinicians to individualize management with heightened accuracy,mitigating risks associated with conventional sedation modalities.Despite the amounting enthusiasm for the use of these therapies,barriers to widespread utilization include expanding equipment availability,staff familiarity and training of safe use.This article delves into the realm of applying inhaled volatile anesthetics in the intensive care unit through discussing their pharmacology,administration considerations in intensive care settings,complication considerations,and listing indications and evidence of the use of volatile anesthetics in the critically ill patient population.

Tracheostomy-related data from an intensive care unit for two consecutive years before the COVID-19 pandemic

BACKGROUND Tracheostomy is commonly used in intensive care unit(ICU)patients who are expected to be on long-term mechanical ventilation or suffer from emergency upper airway obstruction.However,some studies have conflicting findings regarding the optimal technique and its timing and benefits.AIM To provide evidence of practice,characteristics,and outcome concerning tracheostomy in an ICU of a tertiary care hospital.METHODS This was a retrospective cohort study including adult critical care patients in a single ICU for two consecutive years.Patients’demographic characteristics,severity of illness(APACHE II score),level of consciousness[Glasgow Coma Scale(GCS)],comorbidities,timing and type of tracheostomy procedure performed and outcome were recorded.We defined late as tracheostomy placement after 8 days or no tracheotomy.RESULTS Data of 660 patients were analyzed(median age of 60 years),median APACHE II score of 19 and median GCS score of 12 at admission.Tracheostomy was performed in 115 patients,of whom 63 had early and 52 late procedures.Early tracheostomy was mainly executed in case of altered level of consciousness and severe critical illness polyneuromyopathy,however there were no significant statistical results(47.6%vs 36.5%,P=0.23)and(23.8%vs 19.2%,P=0.55)respectively.Regarding the method selected,early surgical tracheostomy(ST)was conducted in patients with maxillofacial injuries(50.0%vs 0.0%,P=0.033),whereas late surgical tracheostomy was selected for patients with goiter(44.4%vs 0.0%P=0.033).Patients with early tracheostomy spent significantly fewer days on mechanical ventilation(15.3±8.5 vs 22.8±9.6,P<0.001)and in ICU in general(18.8±9.1 vs 25.4±11.5,P<0.001).Percutaneous dilatation tracheostomy(PDT)vs ST was preferable in older critical care patients in the case of Central Nervous System underlying cause of admission(62.5%vs 26.3%,P=0.004).ST was the method of choice in compromised airway(31.6%,vs 7.3%P=0.008).A large proportion of patients(88/115)with tracheostomy managed to wean from mechanical ventilation and were transferred out of the ICU(100%vs 17.4%,P<0.001).CONCLUSION PDT was performed more frequently in our cohort.This technique did not affect mechanical ventilation days,ventilator-associated pneumonia(VAP),ICU length of stay,or survival.No complications were observed in the percutaneous or surgical tracheostomy groups.Patients undergoing early tracheostomy benefited in terms of mechanical ventilation days and ICU length of stay but not of discharge status,presence of VAP,or survival.

Driving pressure decoded:Precision strategies in adult respiratory distress syndrome management

Mechanical ventilation(MV)is an important strategy for improving the survival of patients with respiratory failure.However,MV is associated with aggravation of lung injury,with ventilator-induced lung injury(VILI)becoming a major concern.Thus,ventilation protection strategies have been developed to minimize complications from MV,with the goal of relieving excessive breathing workload,improving gas exchange,and minimizing VILI.By opting for lower tidal volumes,clinicians seek to strike a balance between providing adequate ventilation to support gas exchange and preventing overdistension of the alveoli,which can contribute to lung injury.Additionally,other factors play a role in optimizing lung protection during MV,including adequate positive end-expiratory pressure levels,to maintain alveolar recruitment and prevent atelectasis as well as careful consideration of plateau pressures to avoid excessive stress on the lung parenchyma.

Application Effect of Stratified Nursing Intervention for ICU Mechanically Ventilated Patients in the Context of Aspiration Risk Assessment

Objective:To explore the application effect of stratified nursing intervention based on the background of misinspiration risk assessment in mechanically ventilated patients in intensive care unit(ICU).Methods:100 cases of mechanically ventilated patients who were admitted to the ICU of our hospital from March 2022 to March 2023 were selected and divided into an observation group and a control group according to the random number table method,with 50 cases in each of the two groups.The control group was given routine care in ICU,and the observation group was given stratified nursing interventions based on the background of the risk of aspiration assessment on the basis of the control group,and both groups were cared for until they were transferred out of the ICU,and the mechanical ventilation time,ICU stay time,muscle strength score,complication rate,adherence,and satisfaction were observed and compared between the two groups.Results:The mechanical ventilation time and ICU stay time of the observation group were shorter than that of the control group after the intervention;the muscle strength score,compliance and satisfaction of the observation group were higher than that of the control group after the intervention;and the complication rate of the observation group was lower than that of the control group after the intervention,all of which were P<0.05.Conclusion:The application of stratified nursing intervention based on the background of misaspiration risk assessment in ICU mechanically ventilated patients can improve the patient's muscle strength,shorten the time of mechanical ventilation,promote the patient's recovery,reduce the occurrence of complications,and improve the patient's compliance and satisfaction.

Analysis on the Effect of Yiqi Huoxue Decoction Combined with Neuromuscular Electrical Stimulation in Improving ICU-Acquired Debility in Mechanically Ventilated Patients

Objective:To investigate the effect of Yiqi Huoxue decoction combined with neuromuscular electrical stimulation on improving intensive care unit(ICU)acquired debility in mechanically ventilated patients.Methods:50 patients who were admitted to the ICU and received mechanical ventilation treatment in our hospital from June 2022 to June 2023 and were complicated with ICU-acquired neurasthenia were selected,and randomly grouped using the randomized envelope method into two groups:control group with 25 patients who received neuromuscular electrical stimulation alone;observation group with 25 patients who received the traditional Chinese medicine Yiqi Huoxue decoction.Comparison indexes:treatment efficiency,degree of emotional recovery(APACHEⅡscore),muscle strength status(MRC score),motor status(FAC rating),and self-care ability(BI index score).Results:The treatment efficiency of patients in the observation group patients was higher as compared to those in the control group(P<0.05).There was no significant difference in the comparison of the results of the scores(ratings)of each index between the two groups before treatment(P>0.05).After the treatment,the APACHEⅡscores of patients in the observation group were significantly lower as compared to those in the control group,while the MRC scores,FAC ratings,and BI index scores were higher in the observation group than those of the control group patients(P<0.05).Conclusion:The combined application of Yiqi Huoxue decoction and neuromuscular electrical stimulation in the treatment of patients with ICU-acquired neurasthenia complicated by mechanical ventilation significantly enhanced the clinical efficacy,the patient’s muscle strength,motor status,and ability of self-care.Hence,it has high application value and is worthy to be popularized.

Effects of early rehabilitation therapy on patients with mechanical ventilation

BACKGROUND: For patients in intensive care unit(ICU), mechanical ventilation is an effective treatment to survive from acute illness and improve survival rates. However, long periods of bed rest and restricted physical activity can result in side effects. This study aimed to investigate the feasibility of early rehabilitation therapy in patients with mechanical ventilation.METHODS: A randomized controlled trial was carried out. Sixty patients, with tracheal intubation or tracheostomy more than 48 hours and less than 72 hours, were admitted to the ICU of the Affiliated Hospital of Medical College, Qingdao University, from May 2010 to May 2012. These patients were randomly divided into a rehabilitation group and a control group. In the rehabilitation group, rehabilitation therapy was performed twice daily, and the training time and intensity were adjusted according to the condition of the patients. Early rehabilitation therapy included heading up actively, transferring from the supine position to sitting position, sitting at the edge of the bed, sitting in chair, transferring from sitting to standing, and ambulating bedside. The patient's body mass index, days to first out of bed, duration of mechanical ventilation, length of ICU stay, APACHE II score, highest FiO2, lowest PaO2/FiO2 and hospital mortality of patients were all compared between the rehabilitation group and the control group. The differences between the two groups were compared using Student's t test.RESULTS: There was no significant difference in body mass index, APACHE II score, highest FiO2, lowest PaO2/FiO2 and hospital mortality between the rehabilitation group and the control group(P>0.05). Patients in the rehabilitation group had shorter days to first out of bed(3.8±1.2 d vs. 7.3±2.8 d; P=0.00), duration of mechanical ventilation(5.6±2.1 d vs. 12.7±4.1 d; P=0.005) and length of ICU stay(12.7±4.1 d vs. 15.2±4.5 d; P=0.01) compared with the control group.CONCLUSION: Early rehabilitation therapy was feasible and effective in improving the outcomes of patients with mechanical ventilation.

Intensivists’response to hyperoxemia in mechanical ventilation patients:The status quo and related factors

BACKGROUND:Due to the still sparse literature in China,the investigation of hyperoxemia management is required.Thus,we aim to conduct a retrospective study to provide more information about hyperoxemia management in intensive care unit(ICU)patients.METHODS:We retrospectively screened the medical records of adult patients(age≥18 years)who required mechanical ventilation(MV)≥24 hours from January 1,2018,to December 31,2018.All arterial blood gas(ABG)tested during MV was retrieved,and MV settings were recorded.The median arterial partial pressure of oxygen(PaO2)>120 mmHg(1 mmHg=0.133 kPa)was defined as mild to moderate hyperoxemia,and PaO2>300 mmHg as extreme hyperoxemia.Intensivists’response to hyperoxemia was assessed based on the reduction of fraction of inspired oxygen(FiO2)within one hour after hyperoxemia was recorded.Multivariable logistic regression analysis was performed to determine the independent factors associated with the intensivists’response to hyperoxemia.RESULTS:A total of 592 patients were fi nally analyzed.The median Acute Physiology and Chronic Health Evaluation II(APACHE II)score was 21(15-26).The PaO2,arterial oxygen saturation(SaO2),FiO2,and positive end expiratory pressure(PEEP)were 96.4(74.0-126.0)mmHg,97.8%(95.2%-99.1%),0.4(0.4-0.5),and 5(3-6)cmH2O,respectively.Totally 174(29.39%)patients had PaO2>120 mmHg,and 19(3.21%)patients had extreme hyperoxemia at PaO2>300 mmHg.In cases of mild to moderate hyperoxemia with FiO2≤0.4,only 13(2.20%)patients had a decrease in FiO2 within one hour.The multivariable logistic regression analysis showed that a positive response was independently associated with FiO2(odds ratio[OR]1.09,95%confi dence interval[CI]1.06-1.12,P<0.001),PaO2(OR 1.01,95%CI 1.00-1.01,P=0.002),and working shifts(OR 5.09,95%CI 1.87-13.80,P=0.001).CONCLUSIONS:Hyperoxemia occurs frequently and is neglected in most cases,particularly when mild to moderate hyperoxemia,hyperoxemia with lower FiO2,hyperoxemia during night and middle-night shifts,or FiO2 less likely to be decreased.Patients may be at a risk of oxygen toxicity because of the liberal oxygen strategy.Therefore,further research is needed to improve oxygen management for patients with MV in the ICUs.

Unsteady temperature field of surrounding rock mass in high geothermal roadway during mechanical ventilation

To explore the spatial-temporal evolution law of rock mass temperature in high geothermal roadway during mechar^ical ventilation, a series of experiments were conducted based on the physical simulation test system of thermal and humid environment in high geothermal roadway, which is a method independently developed by China University of Mining and Technology. The results indicate that during ventilation, the disturbed region of the temperature extends gradually from shallow area to deep area in the surrounding rock mass of the roadway. Meanwhile, the temperature increases as the exponential function from shallow area to deep, with steady decrease of the temperature gradient and heat flux. As the ventilation proceeds, the relationship between dimensionless temperature and dimensionless time approximately meets Hill function.

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.

Clinical outcomes of moderate to severe COVID-19 patients receiving invasive vs. non-invasive ventilation

Objective:To evaluate the in-hospital outcome of moderate to severe COVID-19 patients admitted in High Dependency Unit(HDU)in relation to invasive vs.non-invasive mode of ventilation.Methods:In this study,the patients required either non-invasive[oxygen≤10 L/min or>10 L/min through mask or nasal prongs,rebreather masks and bilevel positive airway pressure(BiPAP)]or invasive ventilation.For analysis of 30-day in hospital mortality in relation to use of different modes of oxygen,Kaplan Meier and log rank analyses were used.In the end,independent predictors of survival were determined by Cox regression analysis.Results:Invasive ventilation was required by 15.1%patients while 84.9%patients needed non-invasive ventilation.Patients with evidence of thromboembolism,high inflammatory markers and hypoxemia mainly required invasive ventilation.The 30-day in hospital mortality was 72.7%for the invasive group and 12.9%for the non-invasive group(1.8%oxygen<10 L/min,0.9%oxygen>10 L/min,3.6%rebreather mask and 4.5%BiPAP).The median time from hospital admission to outcome was 7 days for the invasive group and 18 days for the non-invasive group(P<0.05).Age,presence of co-morbidities,number of days requiring oxygen,rebreather,BiPAP and invasive ventilation were independent predictors of outcome.Conclusions:Invasive mechanical ventilation is associated with adverse outcomes possibly due to ventilator associated lung injury.Thus,protective non-invasive ventilation remains the necessary and safe treatment for severely hypoxic COVID-19 patients.

Expression Changes of Early Response Genes in Lung Due to High Volume Ventilation

The expression changes of early response genes due to ventilation with high volume in adult rats in vivo were observed. Forty SD male rats were randomly divided into control and 30, 60, 90 and 120 min ventilation groups, respectively (n=8 in each group). The animals were ventilated with tidal volume of 42 ml/kg and a PEEP level of 0 cmH_2O at a rate of 40 breaths per minute in room air with a ventilator was given to the small animals. The expression of Egr-1, C-jun and IL-1β mRNA and proteins was detected by RT-PCR and immunohistochemical technique, respectively. The pathological changes in lung tissues were examined by HE staining. The results indicated that the expression of Egr-1, C-jun and IL-1β mRNA was detectable at 30th min after overventilation, but there was no significant difference in comparison with that in control group until overventilation for 60 min. However, at 90 and 120 min there was a significent increase as compared with 30 min or control group (P<0.05). The expression of Egr-1, C-jun and IL-1β deteced by immunohistochemical assay also showed a similar tendency of the gradual increase. In the 120 min ventilation group, the expression intensity of Egr-1, C-jun and IL-1β proteins in lung cells was the strongest and the nuclear translocation was increased markedly in comparison with any other groups (P<0.05). HE staining suggested that the degree of lung injury was aggravated gradually with the ventialtion going on and had a similar tendency to the expression of these early response genes and proteins. The current data suggested that overventilation activated and upregulated the expression of early response genes and the expression of these genes may be taken as the early signal to predict the onset and degree of lung injury. These results may demonstrated partially that the expression of early response genes induced by the mechanical stretch is associated with biochamic lung injury.