[Assessment of research efficiency of critical care medicine in hospitals affiliated S university based on data envelopment method: taking the 13th Five-Year Plan period as an example].

OBJECTIVE: To investigate the static and dynamic trends of scientific research efficiency of the critical care medicine in hospitals affiliated S university during the 13th Five-Year Plan period. METHODS: Based on the scientific research data of 16 hospitals affiliated to Beijing S University from 2014 to 2020, the scientific research investment funds and the number of physicians involved in scientific research were selected as input evaluation indexes, and the number of science citation index (SCI) papers, Chinese science citation database (CSCD) papers, and the number of masters and doctors trained were selected as output evaluation indexes, and the evaluation index system of scientific research efficiency of critical care medicine was constructed. SPSS version 23.0 software was used for descriptive data statistics, and data envelopment analysis (DEA)-BCC model and DEA-Malmquist index model of DEAP 2.1 software were used for static and dynamic evaluation of its scientific research efficiency from 2016 to 2020, respectively. RESULTS: (1) The scientific research technical efficiency (TE) of critical care medicine in 16 hospitals affiliated with S universities varied greatly from 2016 to 2020, but pure technical efficiency (PTE) and scale efficiency (SE) were at a good level, and 6-11 affiliated hospitals in critical care medicine kept DEA effective for 5 consecutive years. (2) Dynamic analysis of their total factor productivity (TFP) of scientific research from 2016 to 2020 showed a trend of rising and then falling and then rising again. The mean value was 0.985. The technical efficiency change (TEC) showed a decreasing and then increasing trend, and the technical progress change (TC) showed a slow increasing and then decreasing trend, with a mean value of 0.953. While the mean values of TEC, pure technical efficiency change (PTEC) and scale efficiency change (SEC) were above 1, which showed that the growth of total factor productivity index of research and innovation depended more on the technical efficiency index. CONCLUSIONS: The "gain effect" and "catch-up effect" of scientific research efficiency in the specialty of critical care medicine in hospitals affiliated S universities are obvious, but the "growth effect" is not obvious. "Although the research efficiency of the 13th Five-Year Plan period has been significantly improved, there is still much room for improvement in scientific and technological innovation and international academic influence.

Quercetin inhibits caerulein-induced acute pancreatitis through regulating miR-216b by targeting MAP2K6 and NEAT1.

Acute pancreatitis (AP) is a common acute abdominal disease with high mortality and mortality rates. Increasing evidences clarified that Traditional Chinese Medicine (TCM) adjuvant therapy for AP can be used and it gives a positive effect. Quercetin (3,3',4',5,7-pentahydroxyflavone, QE) is a type of flavone compound with positive effect on cancer and inflammation prevention. The current study aims to identify the effect of QE on AP and potential molecular effect. In this case, caerulein (CAE) induced AP cell and mice model were used. QE alleviated inflammatory mediators TNF-α, IL-6, and IL-10 in experiments. In addition, miR-216b was increased based on QE treatment. In further study, MAP2K6 of p38/MAPK signaling pathway was identified as a direct target of miR-216b, and QE inhibited p38/MAPK signaling pathway through up-regulating miR-216b. Our study also first confirmed that long non-coding RNA NEAT1 is a direct target of miR-216b and can be suppressed by QE. Because of the target, NEAT1, miR-216b, and MAP2K6 formed a competitive endogenous RNA (ceRNA) network. Besides direct target mediated by QE, it also decreased TNF-α which down-regulated TRAF2 and MAP3K5 located on upstream of p38/MAPK signaling and formed a feedback loop. In conclusion, QE has a protective effect on AP through inhibiting p38/MAPK signaling pathway by up-regulating miR-216b and suppressing TNF-α.

[Analysis of related factors of carbapenem resistant Klebsiella pneumoniae infection in patients with artificial airway].

OBJECTIVE: To analyze the clinical characteristics and related influencing factors of carbapenem resistant Klebsiella pneumoniae (CRKP) in patients with artificial airway and mechanical ventilation in intensive care unit (ICU), and provide theoretical basis for clinical prevention of Klebsiella pneumoniae infection. METHODS: The clinical data of patients with pulmonary infection of Klebsiella pneumoniae in ICU of Beijing Shijitan Hospital Affiliated to Capital Medical University from January 2016 to December 2019 were collected. Compared CRKP pneumonia patients (study group) with carbapenem antibiotic sensitive Klebsiella pneumoniae (CSKP) pneumonia patients (control group), the clinical characteristics [gender, age, acute physiology and chronic health evaluation II (APACHE II), duration of mechanical ventilation, proportion of patients with mechanical ventilation > 10 days, use of antibiotics before detection of Klebsiella pneumoniae, white blood cell count (WBC), C-reactive protein (CRP), procalcitonin (PCT), albumin, bedridden for more than 1 month before admission, 28-day mortality] were analyzed. The drug resistance rates of Klebsiella pneumoniae in both groups and difference of drug resistance rate of Klebsiella pneumoniae to different antibiotics from 2016 to 2019 were compared. The risk factors of CRKP infection were analyzed by multivariate Logistic regression, and the related drug resistance genes were detected. RESULTS: Compared with the control group, the study group was older [years old: 81.5 (72.0, 86.0) vs. 78.0 (71.0, 80.5)], APACHE II [point: 25.00 (20.00, 34.00) vs. 19.00 (14.00, 23.25)] and proportion of patients with mechanical ventilation > 10 days [63.2% (182/288) vs. 12.8% (10/78)], the use of ß-lactamase inhibitor antibiotics before detection of Klebsiella pneumoniae [75.69% (218/288) vs. 30.77% (24/78)], the use of carbapenems [79.86% (230/288) vs. 41.03% (32/78)], the use of more than two kinds of antibiotics [80.90% (233/288) vs. 29.49% (23/78)], proportion of patients staying in bed for more than 1 month before admission [40.97% (118/288) vs. 11.54% (9/78)] and WBC [×109/L: 9.72 (6.41, 14.69) vs. 7.57 (5.84, 12.61)], CRP [mg/L: 74.45 (36.30, 158.88) vs. 39.22 (13.68, 92.51)], PCT [µg/L: 3.87 (0.82, 19.24) vs. 0.51 (0.25, 5.71)], 28-day mortality [21.5% (62/288) vs. 10.3% (8/78)] were higher, albumin [g/L: 24.1 (18.3, 28.6) vs. 30.1 (23.8, 35.1)] was lower, duration of mechanical ventilation [days: 16.5 (9.0, 19.0) vs. 7.0 (5.0, 10.0)] was longer, the proportion of patients with chronic obstructive pulmonary disease [COPD: 35.76% (103/288) vs. 11.54% (9/78)], malignant tumor [18.06% (52/288) vs. 5.13% (4/78)], renal failure [31.94% (92/288) vs. 11.54% (9/78)], shock [51.74% (149/288) vs. 19.23% (15/78)] were higher, and the differences were statistically significant (all P < 0.05). The drug resistance rates of Klebsiella pneumoniae to aztreonam, piperacillin/tazobactam, imipenem and ciprofloxacin were statistically significant (all P < 0.05); the drug resistance rates of Klebsiella pneumoniae to aztreonam and piperacillin/tazobactam were the highest in 2019 (88.17% and 86.02%, respectively), and the lowest in 2016 (70.65% and 57.61%, respectively). The drug resistance rate to imipenem was the highest in 2018 (86.32%), the lowest in 2016 (59.78%); the resistance rate to ciprofloxacin was the highest in 2016 (76.09%), and the lowest in 2018 (53.68%). The resistance rates of ceftetan, amikacin, piperacillin/tazobactam, ceftazidime, ceftriaxone and gentamicin in the study group were significantly higher than those in the control group (82.99% vs. 62.82%, 49.31% vs. 17.95%, 75.69% vs. 60.26%, 81.25% vs. 64.10%, 80.21% vs. 58.97%, 91.32% vs. 60.26%, all P < 0.05). Logistic regression analysis showed that COPD, severe hypoproteinemia, mechanical ventilation time > 10 days and the use of carbapenem antibiotics before detection of Klebsiella pneumoniae were independent risk factors of CRKP infection. Gene detection showed that there were TEM, KPC, AmpC, AAC(3)-II, ant(3")-I, qnrS and other drug resistance genes in CRKP. The detection rate of TEM was the highest (74.00%), and qnrA was the lowest (6.67%). CONCLUSIONS: The occurrence of CRKP in ICU patients with artificial airway and mechanical ventilation is related to many factors. It is necessary to shorten the mechanical ventilation time, avoid the nonstandard use of carbapenem antibiotics, and improve the serum albumin level, so as to reduce the incidence of CRKP pneumonia and improve the prognosis of patients.

Predictive model for acute respiratory distress syndrome events in ICU patients in China using machine learning algorithms: a secondary analysis of a cohort study.

BACKGROUND: To develop a machine learning model for predicting acute respiratory distress syndrome (ARDS) events through commonly available parameters, including baseline characteristics and clinical and laboratory parameters. METHODS: A secondary analysis of a multi-centre prospective observational cohort study from five hospitals in Beijing, China, was conducted from January 1, 2011, to August 31, 2014. A total of 296 patients at risk for developing ARDS admitted to medical intensive care units (ICUs) were included. We applied a random forest approach to identify the best set of predictors out of 42 variables measured on day 1 of admission. RESULTS: All patients were randomly divided into training (80%) and testing (20%) sets. Additionally, these patients were followed daily and assessed according to the Berlin definition. The model obtained an average area under the receiver operating characteristic (ROC) curve (AUC) of 0.82 and yielded a predictive accuracy of 83%. For the first time, four new biomarkers were included in the model: decreased minimum haematocrit, glucose, and sodium and increased minimum white blood cell (WBC) count. CONCLUSIONS: This newly established machine learning-based model shows good predictive ability in Chinese patients with ARDS. External validation studies are necessary to confirm the generalisability of our approach across populations and treatment practices.

Melatonin-Mediated Pak2 Activation Reduces Cardiomyocyte Death Through Suppressing Hypoxia Reoxygenation Injury-Induced Endoplasmic Reticulum Stress.

Cardiac reperfusion injury has been found to be associated with endoplasmic reticulum (ER) stress. Recently, p21-activated kinase 2 (Pak2) has been identified as a primary mediator of ER stress in chronic myocardial injury. Melatonin, a biological clock-related hormone, has been demonstrated to attenuate heart reperfusion burden by modulating ER stress and mitochondrial function. The aim of our study was to explore whether reperfusion-induced ER stress is modulated by melatonin through Pak2. Hypoxia reoxygenation (HR) was used in vitro to mimic reperfusion injury in cardiomyocytes. ER stress, oxidative stress, calcium overload, and cell death were measured through Western blotting, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, and immunofluorescence with the assistance of siRNA transfection and pathway blocker treatment. The results of our study demonstrated that HR decreased the levels of Pak2 in cardiomyocytes in vitro, and inactivation of Pak2 was associated with ER stress, oxidative stress, calcium overload, caspase-12 activation, and cardiomyocytes apoptosis in vitro. Interestingly, melatonin treatment attenuated HR-mediated ER stress, redox imbalance, calcium overload, and caspase-12-related cardiomyocytes apoptosis, and these protective effects were dependent on Pak2 upregulation. Knockdown of Pak2 abolished the beneficial actions exerted by melatonin on HR-treated cardiomyocytes in vitro. Finally, we found that melatonin reversed Pak2 expression by activating the AMPK pathway and blockade of the AMPK pathway suppressed Pak2 upregulation and cardiomyocytes survival induced by melatonin in the presence of HR stress. Overall, our study reports that the AMPK-Pak2 axis, a novel signaling pathway modulated by melatonin, sends prosurvival signals for cardiomyocytes reperfusion injury through attenuation of ER stress in vitro.

Dexmedetomidine improves the outcomes in paediatric cardiac surgery: a meta-analysis of randomized controlled trials.

OBJECTIVES: Dexmedetomidine has been shown to decrease cardiac complications in adults undergoing cardiac surgery. Results from clinical trials of dexmedetomidine on outcomes following paediatric cardiac surgery are controversial. METHODS: We searched EMBASE, PubMed and Cochrane CENTRAL databases for randomized controlled trials comparing the effect of dexmedetomidine versus placebo or other anaesthetic drugs in paediatric patients undergoing cardiac surgery. The primary outcome was the duration of mechanical ventilation. The secondary outcomes were intensive care unit stay, hospital length of stay (LOS), incidence of junctional ectopic tachycardia and postoperative deaths. RESULTS: Nine trials with a total of 837 patients were selected. Compared with controls, dexmedetomidine significantly reduced the postoperative duration of mechanical ventilation [in hours; n = 837; weighted mean difference -2.20, 95% confidence interval (CI) -3.51 to -0.90; P = 0.001; I2 = 97%], intensive care unit LOS (in days; n = 737; weighted mean difference -0.47, 95% CI -0.90 to -0.03; P = 0.03; I2 = 97%) and hospital LOS (in days; n = 291; weighted mean difference -1.80, 95% CI -3.36 to -0.25; P = 0.02; I2 = 96%). Dexmedetomidine also significantly reduced the incidence of postoperative junctional ectopic tachycardia (21/292 vs 50/263; risk ratio 0.40, 95% CI 0.25-0.64; P = 0.0001; I2 = 0.0%), but there was no difference between groups in postoperative deaths (4/182 vs 6/153; odds ratio 0.54, 95% CI 0.15-1.93; P = 0.34; I2 = 0.0%). CONCLUSIONS: Perioperative administration of dexmedetomidine to paediatric patients undergoing cardiac surgery may shorten the duration of mechanical ventilation, LOS in the intensive care unit and in the hospital and reduce the incidence of junctional ectopic tachycardia. More high-quality randomized controlled trials are encouraged to verify the beneficial effect of dexmedetomidine before its clinical application in paediatric patients undergoing surgery for congenital heart disease.

Application of dead space fraction to titrate optimal positive end-expiratory pressure in an ARDS swine model.

This study aimed to apply the dead space fraction [ratio of dead space to tidal volume (VD/VT)] to titrate the optimal positive end-expiratory pressure (PEEP) in a swine model of acute respiratory distress syndrome (ARDS). Twelve swine models of ARDS were constructed. A lung recruitment maneuver was then conducted and the PEEP was set at 20 cm H2O. The PEEP was reduced by 2 cm H2O every 10 min until 0 cm H2O was reached, and VD/VT was measured after each decrement step. VD/VT was measured using single-breath analysis of CO2, and calculated from arterial CO2 partial pressure (PaCO2) and mixed expired CO2 (PeCO2) using the following formula: VD/VT = (PaCO2 - PeCO2)/PaCO2. The optimal PEEP was identified by the lowest VD/VT method. Respiration and hemodynamic parameters were recorded during the periods of pre-injury and injury, and at 4 and 2 cm H2O below and above the optimal PEEP (Po). The optimal PEEP in this study was found to be 13.25±1.36 cm H2O. During the Po period, VD/VT decreased to a lower value (0.44±0.08) compared with that during the injury period (0.68±0.10) (P<0.05), while the intrapulmonary shunt fraction reached its lowest value. In addition, a significant change of dynamic tidal respiratory compliance and oxygenation index was induced by PEEP titration. These results indicate that minimal VD/VT can be used for PEEP titration in ARDS.

Plasma Neutrophil Elastase and Elafin as Prognostic Biomarker for Acute Respiratory Distress Syndrome: A Multicenter Survival and Longitudinal Prospective Observation Study.

BACKGROUND: Neutrophil elastase (HNE) is a destructive enzyme and plays crucial roles in the pathophysiology of acute respiratory distress syndrome (ARDS). Endogenous proteinase inhibitors elafin (PI3) is important to protect against lung tissue destruction. We proposed to examine whether HNE and PI3 serve as prognostic biomarkers for ARDS. METHODS: This study is a survival and longitudinal analysis of plasma profiles of HNE and PI3 in ARDS patients from a multicenter prospective observational cohort in Beijing, China. Plasma samples were collected on day-1, day-3, and day-7 of study enrollment. RESULTS: HNE levels were higher in ARDS non-survivors than survivors, whereas PI3 showed opposite direction for all three measurements (P < 0.01 for all). Patients with HNE level above median and PI3 level below median values had the lowest survival probability and died the fastest. There was a significant longitudinal effect of HNE levels and PI3 level on mortality. Receiver-operating characteristic analysis demonstrated combination of HNE and PI3 had the discrimination ability for 28-day mortality (area under the receiver-operating characteristic curve [AUC]: 0.76), better than the combination of Berlin categories and APACHE II (AUC: 0.63). The addition of HNE and PI3 to Berlin categories and APACHE II has significantly improved the prognostic discrimination ability (AUC: 0.81, P < 0.0001). CONCLUSIONS: Imbalance between HNE and PI3 levels in ARDS patients was associated with ARDS mortality. By combining these biomarkers with Berlin categories and APACHE II, prognostic power of ARDS was greatly improved. Circulation levels of HNE and PI3 may have the potential to predict ARDS mortality and better inform clinicians about ARDS mortality risk.

A novel insight in exploring the positive end expiratory pressure for sustained ventilation after lung recruitment in a porcine model of acute respiratory distress syndrome.

The aim of the present study was to explore a novel insight to determine the positive end expiratory pressure (PEEP) for sustained ventilation after lung recruitment in an acute respiratory distress syndrome (ARDS) model. Continuous infusion of oleic acid was performed to establish a ARDS model. Pressure control ventilation (PCV) was applied for lung recruitment with PEEP of 20 cm H2O. After lung recruitment, maneuver was changed to volume-controlled ventilation and PEEP titration were performed by decreasing PEEP gradually starting from the level of 20 cm H2O. The optimal level of PEEP for sustained ventilation was set as the lowest PEEP until oxygen partial pressure (PaO2) plus carbon dioxide partial pressure (PaCO2) ≥400 mmHg. Hemodynamic and respiratory parameters at basal level, ARDS state and different levels of PEEP around the optimal PEEP were recorded. The defined optimal PEEP was 13.14 ± 1.35 cm H2O. Respiratory parameters including intrapulmonary shunt (Qs/Qt) and arterial oxygen saturation (SaO2) were significantly improved by various levels of PEEP for sustained ventilation after lung recruitment (P<0.05). Static compliance (Cst) and dynamic compliance (Cdyn) were also significantly increased after application of different levels of PEEP ventilation after lung recruitment (P<0.05). There was no significant statistic difference on most hemodynamic parameters (P>0.05) between various levels of PEEP. The application of different PEEP levels around the defined optimal PEEP had an obvious improvement on respiratory mechanics and gas exchange for collapsed lung tissue without influencing the hemodynamics.

[Risk factors of the occurence and death of acute respiratory distress syndrome: a prospective multicenter cohort study].

OBJECTIVE: To explore the risk factors of the occurence and 28-day death of acute respiratory distress syndrome (ARDS) in intensive care unit (ICU). METHODS: A prospective multicentral cohort study was conducted. The patients from five ICUs of grade A tertiary hospitals in Beijing from July 2009 to March 2014, including sepsis, septic shock, trauma, pneumonia, aspiration, massive blood transfusion, bacteremia and pulmonary contusion, were enrolled. Researchers in each center reported the records with uniform tables, which included demographic, systemic conditions, the primary disease, and the severity within 24 hours, past history and so on. According to the admission diagnosis in ICU, these patients were divided into ARDS group and other severe disease control group. The risk factors of occurence and prognosis of ARDS were analyzed by univariate analysis, multivariate logistic regression and multivariate COX regression analysis. Kaplan-Meier method was applied to draw the 28-day survival curves of the two groups. RESULTS: There were 343 critical patients included in this prospective multicenter cohort study, of which 163 patients who developed ARDS were considered as ARDS group (2 case lost to follow-up, and 49 died) and 180 patients who did not developed ARDS regarded as severe control group (1 case lost to follow-up, and 34 died). The 28-day mortality of ARDS group was significantly higher than that of severe control group [30.43% (49/161) vs. 18.99% (34/179), χ² = 6.013, P = 0.014]. Multivariate logistic analysis showed that aspiration [odds ratio (OR) = 6.390, 95% confidence interval (95% CI) =2.046-19.953, P = 0.001], history of alcohol (OR=4.854, 95% CI = 1.730-13.617, P = 0.003), sepsis (OR = 2.859, 95% CI=1.507-5.425, P = 0.001), pneumonia (OR = 2.822, 95% CI = 1.640-4.855, P<0.001), acute physiology and chronic health evaluation II (APACHEII) score (OR=1.050, 95%CI=1.007-1.094, P=0.022) were significantly associated with increased risk of ARDS occurence. When respiratory rate>30 beats/min (OR=3.305, 95%CI = 1.910-5.721, P<0.001), heart rate>100 beats/min (OR = 2.101, 95% CI = 1.048-4.213, P = 0.037) happened in critically ill patients, it highly suggested ARDS would happen. The proportion of the patients whose serum creatinine>176.8 µmol/L in ARDS group was lower than that in control group (OR = 0.387, 95% CI = 0.205-0.733, P = 0.004). Multivariate COX regression analysis showed that old age and septic shock were significantly associated with the increased risk of in 28-day death of ARDS [advanced age: hazard ratio (HR)=1.040, 95%CI=1.018-1.064, P<0.001; septic shock: HR=3.209, 95% CI = 1.676-6.146, P<0.001]. Kaplan-Meier showed that the survival patients in ARDS group was significantly lower than those in severe control group (χ² = 7.032, P = 0.008). CONCLUSIONS: Among critical ill patients, aspiration, history of alcohol, sepsis, pneumonia, increased APACHEII score were the risk factors of ARDS development. Respiratory rate>30 beats/min and heart rate>100 beats/min could predict the occurrence of ARDS in critical patients. Old age and septic shock were the risk factors of 28-day death of ARDS.

[The significance of non invasive cardiac output monitoring system on evaluating circulatory and respiratory function in pig with acute respiratory distress syndrome].

OBJECTIVE: To investigate the effect of non invasive cardiac output monitoring (NICO) system in pig model with acute respiratory distress syndrome (ARDS), and to provide experimental basis for clinical application. METHODS: Eleven anaesthetized and ventilated ARDS male pig models were induced by intravenously infusing 0.2 mL/kg oleic acid. Lung recruitment was condocted by pressure control ventilation on pigs with ARDS. The optimal positive end-expiratory pressure (PEEP) was determined by optimal dead space fraction [the ratio of dead space to tidal volume (VD/VT)]. Cardiac output (CO) was determined by NICO, the respiratory function was monitored, and the VD/VT, dynamic compliance (Cdyn), oxygenation index (PaO2/FiO2), the volume of alveolar ventilation (Valv) and arterial blood oxygen saturation (SaO2) were recorded before infusing oleic acid, after stabilization of ARDS model and at optimal PEEP level, and the intrapulmonary shunt fraction (Qs/Qt) was calculated. CO was also determined by application of pulse indicated continuous cardiac output (PiCCO), and the linear regression analysis between CO determined by NICO and CO determined by PiCCO was conducted. RESULTS: Seven experimental ARDS pigs model were successfully established. The optimal PEEP identified by the lowest VD/VT method was (15.71 ± 1.80) cmH2O (1 cmH2O = 0.098 kPa). Compared with before infusing oleic acid, VD/VT and Qs/Qt after stabilization of ARDS model were significantly increased [VD/VT: (72.29 ± 8.58)% vs. (56.00 ± 11.06)%, Qs/Qt: (21.04 ± 15.05)% vs. (2.00 ± 1.32)%, both P<0.05], and SaO2and Valv were significantly decreased [SaO2: 0.888 ± 0.108 vs. 0.999 ± 0.053, Valv (mL): 92.06 ± 35.22 vs. 146.11 ± 45.43, both P<0.05]. VD/VT, Qs/Qt, SaO2and Cdyn at optimal PEEP level were improved to the levels before infusing oleic acid [(61.07 ± 9.30)%, (3.21 ± 6.10)%, 0.989 ± 0.025, (117.14 ± 41.14)mL]. Cdyn and PaO2/FiO2after stabilization of ARDS model were significantly lowered compared with those before infusing oleic acid [Cdyn (mL/cmH2O): 14.43 ± 5.50 vs. 38.14 ± 6.72, PaO2/FiO2(mmHg, 1 mmHg = 0.133 kPa): 78.71 ± 23.22 vs. 564.37 ± 158.85, both P < 0.05]. Cdyn and PaO2/FiO2at optimal PEEP level [(19.71 ± 4.86)%, (375.49 ± 141.30) mmHg] were elevated compared with the levels after stabilization of ARDS model (both P <0 .05), but still lower than those before infusing oleic acid (both P < 0.05). Compared with the levels after stabilization of ARDS model, CO at optimal PEEP level showed obvious decrease from (4.18 ± 2.46) L/min to (3.95 ± 2.69) L/min without significant difference (P > 0.05). There was linear correlation between CO determined by NICO and CO determined by PiCCO (r²=0.925, P < 0.001). CONCLUSIONS: NICO technique provides a useful and accurate non invasive estimation of CO and respiratory function.VD/VT provided by NICO can titrate the optimal PEEP in patients with ARDS.