Clinical prediction scores predicting weaning failure from invasive mechanical ventilation:Role and limitations

Invasive mechanical ventilation(IMV)has become integral to modern-day critical care.Even though critically ill patients frequently require IMV support,weaning from IMV remains an arduous task,with the reported weaning failure(WF)rates being as high as 50%.Optimizing the timing for weaning may aid in reducing time spent on the ventilator,associated adverse effects,patient discomfort,and medical care costs.Since weaning is a complex process and WF is often multifactorial,several weaning scores have been developed to predict WF and aid decision-making.These scores are based on the patient's physiological and ventilatory parameters,but each has limitations.This review highlights the current role and limitations of the various clinical prediction scores available to predict WF.

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.

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.

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.

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.

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.

Early and minimal changes in serum creatinine can predict prognosis in elderly patients receiving invasive mechanical ventilation:A retrospective observational study

BackgroundEmerging evidence suggests that minimal acute kidney injury (stage 1 AKI) is associated with increased hospital mortality rates. However, for those who do not meet the AKI diagnostic criteria, whether a small increase in serum creatinine (SCr) levels is associated with an increased mortality rate in elderly patients is not known. Therefore, we aimed to investigate small elevations in SCr of <26.5 µmol/L within 48 h after invasive mechanical ventilation (MV) on the short-term mortality of critically ill patients in the geriatric population.MethodsWe conducted a retrospective, observational, multicenter cohort study enrolling consecutive elderly patients (≥75 years) who received invasive MV from January 2008 to December 2020. Recursive partitioning was used to calculate the ratio of SCr rise from baseline within 48 h after MV and divided into six groups, (1) <10%, (2) 10%–<20%, (3) 20%–<30%, (4) 30%–<40%, (5) 40%–<50%, and (6) ≥50%, where the reference interval was defined as the ratio <10% based on an analysis, which confirmed that the lowest mortality risk was found in this range. Clinical data and laboratory data were noted. Their general conditions and clinical characteristics were compared between the six groups. Prognostic survival factors were identified using Cox regression analysis. Kaplan–Meier survival analysis was employed for the accumulative survival rate.ResultsA total of 1292 patients (1171 men) with a median age of 89 (interquartile range: 85–92) with MV were suitable for further analysis. In all, 376 patients had any stage of early AKI, and 916 patients had no AKI. Among 916 non-AKI patients, 349 patients were in the ratio <10%, 291 in the 10%–<20% group, 169 in the 20%–<30% group, 68 in the 30%–<40% group, 25 in the 40%–<50% group, and 14 in the ≥50% group. The 28-day mortality rates in the six groups from the lowest (<10%) to the highest (≥50%) were 8.0%, 16.8%, 28.4%, 54.4%, 80.0%, and 85.7%, respectively. In the multivariable-adjusted analysis, patients with a ratio of 10%–<20% (hazard ratio [HR]=2.244;95% confidence interval [CI]: 1.410 to 3.572;P=0.001), 20%–<30% (HR=3.822;95% CI: 2.433 to 6.194;P <0.001), 30%–<40% (HR=10.472;95% CI: 6.379 to 17.190;P <0.001), 40%–<50% (HR=13.887;95% CI: 7.624 to 25.292;P <0.001), and ≥50% (HR=13.618;95% CI: 6.832 to 27.144;P <0.001) had relatively higher 28-day mortality rates. The 90-day mortality rates in the six strata were 30.1%, 35.1%, 45.0%, 60.3%, 80.0%, and 85.7%, respectively. Significant interactions were also observed between the ratio and 90-day mortality: patients with a ratio of 10%–<20% (HR=1.322;95% CI: 1.006 to 1.738;P=0.045), 20%–<30% (HR=1.823;95% CI: 1.356 to 2.452;P <0.001), 30%–<40% (HR=3.751;95% CI: 2.601 to 5.410;P <0.001), 40%–<50% (HR=5.735;95% CI: 3.447 to 9.541;P <0.001), and ≥50% (HR=6.305;95% CI: 3.430 to 11.588;P <0.001) had relatively higher 90-day mortality rates.ConclusionsOur study suggests that a ≥ 10% SCr rise from baseline within 48 h after MV was independently associated with short-term all-cause mortality in mechanically ventilated elderly patients.

Predictive performance of the variation rate of the driving pressure on the outcome of invasive mechanical ventilation in patients with acute respiratory distress syndrome

Purpose:To assess the value of the driving pressure variation rate(ΔP%)in predicting the outcome of weaning from invasive mechanical ventilation in patients with acute respiratory distress syndrome.Methods:In this case-control study,a total of 35 patients with moderate-severe acute respiratory distress syndrome were admitted to the intensive care unit between January 2022 and December 2022 and received invasive mechanical ventilation for at least 48 h were enrolled.Patients were divided into successful weaning group and failed weaning group depending on whether they could be removed from ventilator support within 14 days.Outcome measures including driving pressure,PaO2:FiO2,and positive end-expiratory pressure,etc.were assessed every 24 h from day 0 to day 14 until successful weaning was achieved.The measurement data of non-normal distribution were presented as median(Q1,Q3),and the differences between groups were compared by Wilcoxon rank sum test.And categorical data use the Chi-square test or Fisher's exact test to compare.The predictive value ofΔP%in predicting the outcome of weaning from the ventilator was analyzed using receiver operating characteristic curves.Results:Of the total 35 patients included in the study,17 were successful vs.18 failed in weaning from a ventilator after 14 days of mechanical ventilation.The cut-off values of the medianΔP%measured by Operator 1 vs.Operator 2 in the first 4 days were≥4.17%and 4.55%,respectively(p<0.001),with the area under curve of 0.804(sensitivity of 88.2%,specificity of 64.7%)and 0.770(sensitivity of 88.2%,specificity of 64.7%),respectively.There was a significant difference in mechanical ventilation duration between the successful weaning group and the failure weaning group(8(6,13)vs.12(7.5,17.3),p=0.043).The incidence of ventilator-associated pneumonia in the successful weaning group was significantly lower than in the failed weaning group(0.2‰vs.2.3‰,p=0.001).There was a significant difference noted between these 2 groups in the 28-day mortality(11.8%vs.66.7%,p=0.003).Conclusion:The medianΔP%in the first 4 days of mechanical ventilation showed good predictive performance in predicting the outcome of weaning from mechanical ventilation within 14 days.Further study is needed to confirm this finding.

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.

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.

Longer duration of initial invasive mechanical ventilation is still a crucial risk factor for moderate‑to‑severe bronchopulmonary dysplasia in very preterm infants:a multicentrer prospective study

Objectives We aimed to evaluate the risk factors for moderate-to-severe bronchopulmonary dysplasia(BPD)and focus on discussing its relationship with the duration of initial invasive mechanical ventilation(IMV)in very preterm neonates less than 32 weeks of gestational age(GA).Methods We performed a prospective cohort study involving infants born at 23–31 weeks of GA who were admitted to 47 different neonatal intensive care unit(NICU)hospitals in China from January 2018 to December 2021.Patient data were obtained from the Sina-northern Neonatal Network(SNN)Database.Results We identified 6538 very preterm infants,of whom 49.5%(3236/6538)received initial IMV support,and 12.6%(823/6538)were diagnosed with moderate-to-severe BPD symptoms.The median duration of initial IMV in the moderateto-severe BPD group was 26(17–41)days,while in the no or mild BPD group,it was 6(3–10)days.The incidence rate of moderate-to-severe BPD and the median duration of initial IMV were quite different across different GAs.Multivariable logistic regression analysis showed that the onset of moderate-to-severe BPD was significantly associated with the duration of initial IMV[adjusted odds ratio(AOR):1.97;95%confidence interval(CI):1.10–2.67],late-onset neonatal sepsis(LONS),and patent ductus arteriosus(PDA).Conclusion In this multicenter cohort study,the duration of initial IMV was still relatively long in very premature infants,and the longer duration of initial IMV accounts for the increased risk of moderate-to-severe BPD.

Mechanical ventilation and outcomes in COVID-19 patients admitted to intensive care unit in a low-resources setting: A retrospective study

Objective:To describe the strategies and outcomes of mechanical ventilation in a poorly equipped facility.Methods:This retrospective descriptive study included patients with COVID-19 who were admitted to the intensive care unit(ICU)and mechanically ventilated between September 1,2020,and May 31,2021.Data were collected from medical records and databases.Results:54 Patients aged(62.9±13.3)years were included.Among these cases,79.6%had at least one comorbidity.On admission,all patients had hypoxia.The median peripheral oxygen saturation in room air was 76%(61%,83%).Non-invasive ventilation(NIV)was performed in 75.9%of the patients,and invasive mechanical ventilation(IMV)in 68.5%.IMV was performed on patients due to severe coma(8.1%),failure of standard oxygen therapy(27.0%),and failure of NIV(64.9%).An arterial blood gas test was performed in 14.8%of the patients.NIV failed in 90.2%of cases and succeeded in 9.8%.IMV was successful in 5.4%of cases,vs.94.6%of mortality.The overall mortality rate of patients on ventilation in the ICU was 88.9%.The causes of death included severe respiratory distress syndrome(85.2%),multiple organ failure(14.8%),and pulmonary embolism(13.0%).Conclusions:The ventilation management of COVID-19 patients in the ICU with NIV and IMV in a scarce resource setting is associated with a high mortality rate.Shortcomings are identified in ventilation strategies,protocols,and monitoring.Required improvements were also proposed.

Clinical Analysis of Early Noninvasive Mechanical Ventilation in the Treatment of Acute Left Heart Failure Complicated with Respiratory Failure

Objective To evaluate the efficacy of early and non-early non-invasive mechanical ventilation(NIV) for acute left heart failure and respiratory failure. Methods 29 cases of patients with acute left heart failure and respiratory failure treated by NIV were selected from our department from August 2016 to March 2019. According to the time of initiation of noninvasive mechanical ventilation, the patients were divided into the early treatment group(group A, treatment with NIV immediately after admission, n=15) and the non-early treatment group(group B, treatment with NIV for 2 h after admission, n=14), the improvement time, mechanical ventilation time, effective rate, intubation rate and fatality rate were compared between the two groups. Results The improvement time of patients in group A was(4.8±2.5) hours, the time of mechanical ventilation was(9.6±3.2) hours, the improvement time of group B was(6.8±2.6) hours, and the time of mechanical ventilation(12.8±4.4) hours. There were significant differences between the two groups(P<0.05). In group A, 13 patients were cured, 2 patients were intubated, 1 patient died, 10 patients in group B were cured, 4 patients were intubated, and 2 patients died. The difference in cure rate, intubation rate and mortality was statistically significant(P<0.05). Conclusion The treatment of acute left heart failure and respiratory failure is effective, and early application can improve the cure rate, reduce intubation and mortality.

Hygrometry behavior during high-flow nasal oxygen therapy and non-invasive mechanical ventilation:A narrative review of bench to clinical studies

Recently,there has been growing interest in knowing the best hygrometry level during high-flow nasal oxygen and non-invasive ventilation(NIV)and its potential influence on the outcome.Various studies have shown that breathing cold and dry air results in excessive water loss by nasal mucosa,reduced mucociliary clearance,in-creased airway resistance,reduced epithelial cell function,increased inflammation,sloughing of tracheal epithe-lium,and submucosal inflammation.With the Coronavirus Disease 2019 pandemic,using high-flow nasal oxygen with a heated humidifier has become an emerging form of non-invasive support among clinicians.However,we cannot always assume stable humidification.Similarly,there are no clear guidelines for using humidification dur-ing NIV,although humidification of inspired gas during invasive ventilation is an accepted standard of care.NIV disturbs the normal physiological system that warms and humidifies inspired gases.If NIV is supplied through an intensive care unit ventilator that utilizes anhydrous gases from compressed wall air and oxygen,the risk of dry-ness increases.In addition,patients with acute respiratory failure tend to breathe through the mouth during NIV,which is a less efficient route than nasal breathing for adding heat and moisture to the inspired gas.Obstructive sleep apnea syndrome is one of the most important indications for chronic use of NIV at home.Available data suggest that up to 60%of patients with obstructive sleep apnea syndrome who use continuous positive airway pressure therapy experience nasal congestion and dryness of the mouth and nose.Therefore,humidifying the inspired gas in NIV may be essential for patient comfort and compliance with treatment.We aimed to review the available bench and clinical studies that addressed the utility of hygrometry in NIV and nasal high-flow oxygen and discuss the technical limitations of different humidification systems for both systems.

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.

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.

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.

Evaluation of progressive early rehabilitation training mode in intensive care unit patients with mechanical ventilation

BACKGROUND Mechanical ventilation is a common resuscitation method in the intensive care unit(ICU).Unfortunately,this treatment process prolongs the ICU stay of patients with an increased incidence of delirium,which ultimately affects the prognosis.AIM To evaluate the effect of progressive early rehabilitation training on treatment and prognosis of patients with mechanical ventilation in ICU.METHODS The convenience sampling method selected 190 patients with mechanical ventilation admitted to the Fourth Hospital of Hebei Medical University from March 2020 to March 2021.According to the random number table method,they were divided into the control and intervention groups.The control group received routine nursing and rehabilitation measures,whereas the intervention group received progressive early rehabilitation training.In addition,the incidence and duration of delirium were compared for the two groups along with mechanical ventilation time,ICU hospitalization time,functional independence measure(FIM)score,Barthel index,and the incidence of complications(deep venous thrombosis,pressure sores,and acquired muscle weakness).RESULTS In the intervention group,the incidence of delirium was significantly lower than in the control group(28%vs 52%,P<0.001).In the intervention group,the duration of delirium,mechanical ventilation time,and ICU stay were shorter than in the control group(P<0.001).The FIM and Barthel index scores were significantly higher in the intervention group than the control group(P<0.001).The total incidence of complications in the intervention group was 3.15%,which was lower than 17.89%in the control group(P<0.001).CONCLUSION Progressive early rehabilitation training reduced the incidence of delirium and complications in ICU patients with mechanical ventilation,which improved prognosis and quality of life.

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.

Univariate Risk Factors for Prolonged Mechanical Ventilation in Patients Undergoing Prosthetic Heart Valves Replacement Surgery

Data from 736 patients undergoing prosthetic heart valve replacement surgery and concomitant surgery （combined surgery） from January 1998 to January 2004 at Union Hospital were retrospectively reviewed. Univariate logistic regression analyses were conducted to identity risk factors for prolonged mechanical ventilation. The results showed that prolonged cardiopulmonary bypass duration, prolonged aortic cross clamp time and low ejection fraction less than 50 percent （50 %） were found to be independent predictors for prolonged mechanical ventilation. Meanwhile age, weight, and preoperative hospital stay （days） were not found to be associated with prolonged mechanical ventilation. It was concluded that. for age and weight, this might be due to the lower number of old age patients （70 years and above） included in our study and genetic body structure of majority Chinese population that favor them to be in normal weight, respectively.