Epidemiology and outcome of acute respiratory failure in intensive care unit patients

Association of lactate/albumin ratio with in-hospital mortality in ICU patients with acute respiratory failure: A retrospective analysis based on MIMIC-IV database

We aimed to investigate the association between the lactate/albumin ratio (LAR), and in-hospital mortality in critically ill patients with acute respiratory failure. This retrospective cohort study was conducted based on the medical information mart for intensive care-IV database, which included critically ill adult patients with acute respiratory failure whose primary endpoint was in-hospital death. The analyses included curve fitting, a logistic multivariate regression model, and subgroup analysis. In this study, 6028 intensive care unit patients with acute respiratory failure were analyzed. Of these, 1843 (30.57%) died. After adjusting for confounding factors, a nonlinear relationship between LAR and in-hospital mortality was observed, and the risk of death was found to decrease by 81% with a reduction of 1 unit of LAR when it was < 4.46. The association between LAR and in-hospital mortality was not statistically significant when LAR was > 4.46. Hence, the relationship between LAR and in-hospital mortality could only be observed when the LAR was < 4.46. There is a nonlinear relationship between LAR and the risk of in-hospital death in intensive care unit patients with acute respiratory failure, and there is a saturation effect.

Serum human epididymis secretory protein 4 correlates with sepsis-associated acute respiratory distress syndrome and 28-day mortality in critically ill patients

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a severe disease with high mortality, and its primary cause is sepsis. The aim of this study was to detect and evaluate the role of Human epididymis protein 4 (HE4) in sepsis-related ARDS.

METHODS

One hundred and twenty-three critically ill sepsis patients with/without ARDS and 102 healthy controls were enrolled in this study. Blood samples were collected upon admission for quantitative testing of HE4 by chemiluminescent microparticle immunoassay (CMIA). ROC curve analysis and Spearman's correlation analysis were conducted to determine the diagnostic and prognostic value of HE4.

RESULTS

Compared with controls, the serum HE4 concentrations of sepsis patients were elevated, and levels in sepsis patients with ARDS were significantly higher (all p < 0.0001). Moreover, HE4 concentrations were strongly correlated with the clinical severity characteristics of sepsis patients, and ROC curve suggested that the AUC of HE4 applied to discriminate sepsis-ARDS patients from sepsis patients was 0.903. HE4 was also found to be a prognostic biomarker of clinical severity and 28-day mortality among critically ill sepsis patients. Logistic regression analysis showed that HE4 was an independent factor for diagnosis of ARDS. Meanwhile, ROC curve analysis showed that the cut-off value of serum HE4 to discriminate 28-day mortality from sepsis patients (AUC: 0.782) was 646.5 pmol/L.

CONCLUSIONS

The concentration of serum HE4 in patients with sepsis-related ARDS was markedly increased and was significantly correlated with mortality, which suggests that serum HE4 could be a promising diagnostic and prognostic biomarker for ARDS in sepsis patients.

Transbronchial lung biopsy versus transbronchial lung cryobiopsy in critically ill patients with undiagnosed acute hypoxemic respiratory failure: a comparative study

BACKGROUND

In patients with acute hypoxemic respiratory failure whose diagnosis is not established after initial evaluation, obtaining a histopathological diagnosis may improve the patients' prognosis. This study aims to compare the safety profile and diagnostic yields between transbronchial lung biopsy (TBLB) and transbronchial lung cryobiopsy (TBLC) in these patients.

METHODS

A retrospective comparative study was conducted in a 26-bed intensive care unit over a 5-year period. The consecutive patients with acute hypoxemic respiratory failure who underwent TBLB or TBLC were included to determine the potential etiology. Patients characteristics, procedure related complications, pathological and multidisciplinary discussion (MDD) diagnostic yields, treatment modification and 28-day survival were analyzed. Prognostic factors were identified by Cox regression analysis.

RESULTS

Forty-five and 25 consecutive patients underwent TBLB and TBLC, respectively. The patients underwent TBLC were more critical. There was no significant difference in overall procedure related complications of patients underwent TBLB and TBLC [15.6% (7/45) vs 28.0% (7/25), p = 0.212]. The rate of pathological diagnostic yield [72.0% (18/25) vs 37.8% (17/45), p = 0.006], MDD diagnostic yield [84.0% (21/25) vs 55.6% (25/45), p = 0.016] and subsequent treatment modification [84.0% (21/25) vs 57.8% (26/45), p = 0.025] in patients underwent TBLC were significantly higher than those in patients underwent TBLB. Multivariate analysis revealed that MDD diagnosis [HR 0.193 (95% CI 0.047-0.792), p = 0.022] and treatment modification [HR 0.204 (95% CI 0.065-0.638), p = 0.006] may be prognostic protective factors.

CONCLUSIONS

TBLC can lead to an increased chance of establishing a diagnosis, which could significantly improve the patients' prognosis, with an acceptable safety profile.

Antisynthetase syndrome sine myositis presenting as severe acute respiratory failure

A female in her late 40s presented to the emergency department during the COVID-19 pandemic with shortness of breath, fever and productive cough following a recent diagnosis of bilateral non-massive pulmonary emboli. She had elevated inflammatory markers and her chest X-ray revealed bilateral infiltrates. Her SARS-CoV-2 PCR was negative, and she was treated for community-acquired pneumonia. However, despite treatment she rapidly deteriorated and developed severe respiratory failure, requiring mechanical ventilation.On further investigation, she tested positive for anti-Jo-1 antibodies and a diagnosis of antisynthetase syndrome sine myositis was made. This led to successful treatment with high dose corticosteroids and intravenous immunoglobulin.This case highlights an uncommon presentation of a rare condition, as well as the benefits of working in a multidisciplinary team on the intensive care unit.

The effect of N6-methyladenosine (m6A) factors on the development of acute respiratory distress syndrome in the mouse model

Acute respiratory distress syndrome (ARDS) can cause loss of alveolar-capillary membrane integrity and life-threatening immune responses. The underlying molecular mechanisms of ARDS remain unclear. N6-methyladenosine (m6A)-RNA modification plays an important part in many biological processes. However, it is not clear whether ARDS alters RNA methylation in lung tissue. We tried to investigate the changes of m6A-RNA methylation in lung tissues of lipopolysaccharide (LPS)-induced ARDS mice. Lung tissue samples were collected to detect the expression of m6A factors through hematoxylin and eosin (HE) staining, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), immunohistochemical analysis and western blot. The overall m6A levels in lung tissue of ARDS in mouse were detected by UPLC-UV-MS. HE staining showed that the degree of the inflammatory response was more severe in the LPS-3 h group. The mRNA expression of YTHDF1, YTHDC1 and IGFBP3 was remarkably up-regulated at, respectively, 6, 6 and 12 h after LPS treatment. The mRNA expression of METTL16, FTO, METTL3, KIAA1429, RBM15, ALKBH5, YTHDF2, YTHDF3, YTHDC2 and IGFBP2 was significantly down-regulated at 24 h after LPS treatment. The protein expression of METTL16 and FTO increased, YTHDC1, IGFBP3 YTHDF1 and YTHDF3 showed a down-regulation trend after LPS induction. Overall m6A-RNA methylation levels were significantly increased at 6 h after LPS induction. In ARDS mice, LPS-induced m6A methylation may be involved in the expression regulation of inflammatory factors and may play important roles in the occurrence and development of lung tissue. It is suggested that m6A modification may be a promising therapeutic target for ARDS.

Lung ultrasound in a tertiary intensive care unit population: a diagnostic accuracy study

BACKGROUND

Evidence from previous studies comparing lung ultrasound to thoracic computed tomography (CT) in intensive care unit (ICU) patients is limited due to multiple methodologic weaknesses. While addressing methodologic weaknesses of previous studies, the primary aim of this study is to investigate the diagnostic accuracy of lung ultrasound in a tertiary ICU population.

METHODS

This is a single-center, prospective diagnostic accuracy study conducted at a tertiary ICU in the Netherlands. Critically ill patients undergoing thoracic CT for any clinical indication were included. Patients were excluded if time between the index and reference test was over eight hours. Index test and reference test consisted of 6-zone lung ultrasound and thoracic CT, respectively. Hemithoraces were classified by the index and reference test as follows: consolidation, interstitial syndrome, pneumothorax and pleural effusion. Sensitivity, specificity, positive and negative likelihood ratio were estimated.

RESULTS

In total, 87 patients were included of which eight exceeded the time limit and were subsequently excluded. In total, there were 147 respiratory conditions in 79 patients. The estimated sensitivity and specificity to detect consolidation were 0.76 (95%CI: 0.68 to 0.82) and 0.92 (0.87 to 0.96), respectively. For interstitial syndrome they were 0.60 (95%CI: 0.48 to 0.71) and 0.69 (95%CI: 0.58 to 0.79). For pneumothorax they were 0.59 (95%CI: 0.33 to 0.82) and 0.97 (95%CI: 0.93 to 0.99). For pleural effusion they were 0.85 (95%CI: 0.77 to 0.91) and 0.77 (95%CI: 0.62 to 0.88).

CONCLUSIONS

In conclusion, lung ultrasound is an adequate diagnostic modality in a tertiary ICU population to detect consolidations, interstitial syndrome, pneumothorax and pleural effusion. Moreover, one should be careful not to interpret lung ultrasound results in deterministic fashion as multiple respiratory conditions can be present in one patient. Trial registration This study was retrospectively registered at Netherlands Trial Register on March 17, 2021, with registration number NL9344.

Critical Care of Patients With Cardiopulmonary Complications of Sarcoidosis

Sarcoidosis is a systemic inflammatory disease defined by the presence of aberrant granulomas affecting various organs. Due to its multisystem involvement, care of patients with established sarcoidosis becomes challenging, especially in the intensive care setting. While the lungs are typically involved, extrapulmonary manifestations also occur either concurrently or exclusively within a significant proportion of patients, complicating diagnostic and management decisions. The scope of this review is to focus on what considerations are necessary in the evaluation and management of patients with known sarcoidosis and their associated complications within a cardiopulmonary and critical care perspective.

Machine Learning Methods to Predict Acute Respiratory Failure and Acute Respiratory Distress Syndrome

Acute respiratory failure (ARF) is a common problem in medicine that utilizes significant healthcare resources and is associated with high morbidity and mortality. Classification of acute respiratory failure is complicated, and it is often determined by the level of mechanical support that is required, or the discrepancy between oxygen supply and uptake. These phenotypes make acute respiratory failure a continuum of syndromes, rather than one homogenous disease process. Early recognition of the risk factors for new or worsening acute respiratory failure may prevent that process from occurring. Predictive analytical methods using machine learning leverage clinical data to provide an early warning for impending acute respiratory failure or its sequelae. The aims of this review are to summarize the current literature on ARF prediction, to describe accepted procedures and common machine learning tools for predictive tasks through the lens of ARF prediction, and to demonstrate the challenges and potential solutions for ARF prediction that can improve patient outcomes.

Impact of Bedside Combined Cardiopulmonary Ultrasound on Etiological Diagnosis and Treatment of Acute Respiratory Failure in Critically Ill Patients

AIMS AND OBJECTIVES

To prospectively evaluate the impact of cardiopulmonary ultrasound (CPUS) on etiological diagnosis and treatment of critically ill acute respiratory failure (ARF) patients.

DESIGN

This is a prospective observational study conducted in a general intensive care unit (ICU) of a tertiary care center in India. Patients over 18 years old with presence of one of the objective criteria of ARF. Patients either consecutively admitted for ARF to ICU or already admitted to ICU for a different reason but later developed ARF during their hospital stay. Written informed consent in local language was obtained from next of kin.

INTERVENTIONS

All included patients underwent bedside CPUS including lung ultrasound (US) and transthoracic echocardiography plus targeted venous US by single investigator, blinded to clinical data. The US diagnosis of ARF etiology was shared with treating intensivist. Initial clinical diagnosis (ICD) and treatment plan (made before US) of each patient were compared with post-US clinical diagnosis and treatment plan. The changes in diagnosis and treatment up to 24 hours post-US were considered as impact of US.

RESULTS

Mean age of 108 included patients was 45.7 ± 20.4 years (standard deviation). The ICD was correct in 67.5% (73/108) cases, whereas the combined CPUS yielded correct etiological diagnosis in 88% (95/108) cases. Among the 108 included patients, etiological diagnosis of ARF was altered after CPUS in 40 (37%) patients, which included "diagnosis changed" in 18 (17%) and "diagnosis added" in 22 (20%). Treatment plan was changed in 39 (36%) patients after CPUS, which included surgical interventions in 17 (16%), changes in medical therapy in 12 (11%), and changes in ventilation strategy in 4 (3.5%) patients.

CONCLUSION

This study demonstrates that use of combined US approach as an initial test in ARF, improves diagnostic accuracy for identification of underlying etiology, and frequently changes clinical diagnosis and/or treatment.

HOW TO CITE THIS ARTICLE

Barman B, Parihar A, Kohli N, Agarwal A, Dwivedi DK, Kumari G. Impact of Bedside Combined Cardiopulmonary Ultrasound on Etiological Diagnosis and Treatment of Acute Respiratory Failure in Critically Ill Patients. Indian J Crit Care Med 2020;24(11):1062-1070.

Scaling the Need, Benefits, and Risks Associated with COVID-19 Acute and Postacute Care Rehabilitation: A Review

Coronavirus is an RNA virus, which attacks the respiratory system causing complications including severe respiratory distress and pneumonia and many other symptoms. Recently, a novel coronavirus (COVID-19) outbreak emerged in Wuhan, which caused a significant number of infections in China and resulted in a global pandemic. The main aim of this study is to review and summarize the evidence regarding the supportive role of physical rehabilitation techniques in managing COVID-19-associated pneumonia. In this review, we also emphasize the use of rehabilitation techniques in the management of pneumonia in COVID-19-infected patients. Based on the evidence presented, we conclude that certain physical rehabilitation techniques and modalities could be of great support in the management of COVID-19-associated pneumonia. The safety of staff and patients when applying rehabilitation intervention requires attention. The combination of physical rehabilitation and medical treatment would result in improved treatment outcomes, faster recovery, and shorter hospital stay. Many rehabilitation techniques are safe and feasible and can be easily incorporated into the management protocol of COVID-19 victims. Decisions of early rehabilitation induction should be based on the patient's medical condition and tolerability.

Transbronchial lung cryobiopsy may be of value for nonresolving acute respiratory distress syndrome: case series and systematic literature review

BACKGROUND

Identification of pathologic features is helpful for the management of nonresolving acute respiratory distress syndrome (ARDS). Transbronchial lung cryobiopsy (TBLC) is a novel biopsy technique that may have comparable utility to surgical biopsy. The aim of this study was to assess the value of TBLC in patients with nonresolving ARDS.

METHODS

All patients with nonresolving ARDS who underwent TBLC from January 2019 to August 2019 in a tertiary medical ICU were included. In addition, a literature search of TBLC for ARDS was performed by searching PubMed, EMBASE, ATS/ERS/APSR meeting abstracts, ClinicalTrials.gov , and Google Scholar. Data on complications, histologic diagnosis, management changes, and outcomes were analysed.

RESULTS

Five patients (three women and two men) underwent TBLC. None of the patients developed pneumothorax, although two patients developed massive bleeding, which was controlled by continuous occlusion using bronchial blockers. There were no procedure-related deaths. Diffuse alveolar damage (DAD) and alternative histologic patterns were found in two and three patients, respectively, resulting in management changes in all cases. The literature search yielded four studies, which together with the present study comprised data from 25 cases in which TBLC was used in nonresolving ARDS. The summary diagnostic yield was 92% (23/25). Only 44% (11/25) of cases were proven to be DAD. TBLC contributed to management changes in 80% of patients (20/25). Procedure-related complications consisted of pneumothorax (16%, 4/25), significant bleeding (12%, 3/25), and persistent air leaks (8%, 2/25). There were no procedure-related deaths. The follow-up survival rate was 61.9% (13/21).

CONCLUSIONS

The complications of TBLC in selected patients with nonresolving ARDS may be acceptable. The procedure may have a high diagnostic yield and can lead to a re-evaluation of the diagnosis as well as changes in patient management. Further investigations with larger sample sizes are required.

Suppressive Effects of GSS on Lipopolysaccharide-Induced Endothelial Cell Injury and ALI via TNF-α and IL-6

Background. Under septic conditions, LPS induced lung vascular endothelial cell (EC) injury, and the release of inflammatory mediator launches and aggravates acute lung injury (ALI). There are no effective therapeutic options for ALI. Genistein-3'-sodium sulfonate (GSS) is a derivative of native soy isoflavone, which exhibits neuroprotective effects via its antiapoptosis property. However, whether GSS protect against sepsis-induced EC injury and release of inflammatory mediators has not been determined. In this study, we found that GSS not only downregulated the levels of TNF-α and IL-6 in the lung and serum of mice in vivo but also inhibited the expression and secretion of TNF-α and IL-6 in ECs. Importantly, we also found that GSS blocked LPS-induced TNF-α and IL-6 expression in ECs via the Myd88/NF-κB signaling pathway. Taken together, our results demonstrated that GSS might be a promising candidate for sepsis-induced ALI via its regulating effects on inflammatory response in lung ECs.

Genistein-3'-sodium sulphonate protects against lipopolysaccharide-induced lung vascular endothelial cell apoptosis and acute lung injury via BCL-2 signalling

Under septic conditions, Lipopolysaccharide (LPS)‐induced apoptosis of lung vascular endothelial cells (ECs) triggers and aggravates acute lung injury (ALI), which so far has no effective therapeutic options. Genistein‐3′‐sodium sulphonate (GSS) is a derivative of native soy isoflavone, which has neuro‐protective effects through its anti‐apoptotic property. However, whether GSS protects against sepsis‐induced lung vascular endothelial cell apoptosis and ALI has not been determined. In this study, we found that LPS‐induced Myd88/NF‐κB/BCL‐2 signalling pathway activation and subsequent EC apoptosis were effectively down‐regulated by GSS in vitro. Furthermore, GSS not only reversed the sepsis‐induced BCL‐2 changes in expression in mouse lungs but also blocked sepsis‐associated lung vascular barrier disruption and ALI in vivo. Taken together, our results demonstrated that GSS might be a promising candidate for sepsis‐induced ALI via its regulating effects on Myd88/NF‐κB/BCL‐2 signalling in lung ECs.

An interesting case summary of tubercular pneumonia masquerading as viral pneumonia kept on extra-corporeal membrane oxygenation

Mortality in patients with pulmonary tuberculosis remains high, especially in those who develop acute respiratory distress syndrome (ARDS). We herein, report a case of 40 year old female, with ARDS due to severe pulmonary tuberculosis. She was admitted in the intensive care unit of a tertiary care centre. Owing to very poor ABG report, she was intubated and put on Mechanical ventilator support. Bronchoscopy was performed and BAL was extracted, which showed no growth. Further deterioration of gas exchange prompted the decision to put her on ECMO. During her stay on ECMO, she developed massive inta-alveolar hemorrhage following which repeated bronchoscopic interventions were done to remove blood clots. BAL extracted on day 4 and day 8 showed growth of A. baumannii and K. pneumoniae respectively. But BALGeneXpert on day 8 came out to be positive for Mycobacterium Tuberculosis and subsequently ATT was added to her treatment regimen. Her alveolar hemorrhage continued to worsen and subsequently ECMO was removed. After 12 days of hospitalization, she went on to develop bradycardia and could not be rescued. Though the patient's life was lost, this case provided many insights on the use of ECMO in the management of ARDS due to Pulmonary tuberculosis and it should be considered as one of the treatment options.

Interleukin-6 is required for Neuregulin-1 induced HER2 signaling in lung epithelium

A clear understanding of the mechanisms that regulate the alveolar epithelium's barrier is critical to develop new therapeutic strategies to mitigate lung injury. The HER2/HER3 receptor tyrosine kinase complex plays a central role in maintaining the alveolar-capillary barrier. This receptor complex is activated by its ligand, neuregulin-1 (NRG-1). Interleukin-6 (IL-6) is also known to induce HER2 signaling through HER2 transphosphorylation by the IL-6 receptor (IL-6R) complex (1). Due to this interaction, we hypothesized that NRG-1 and IL-6 cooperatively interacted to activate the HER2/HER3 complex. Studies were performed in cultured pulmonary epithelial cells measuring the HER2/IL-6/IL-6R/GP130 interaction and receptor activation by western blotting and confocal microscopy, IL-6 production by ELISA, and IL-6 inhibition using specific antibodies, small molecule inhibitors and shRNA. We found that IL-6 was required for NRG-1 induced activation of HER2 in pulmonary epithelial cells. IL-6 inhibition led to a decrease in NRG-1 induced HER2 activation. The IL-6R and GP130, a subunit of the IL-6R complex, were physically associated with HER2 and were required for NRG-1 induced HER2 activation. Inhibition of GP130, the β-subunit of the IL-6 receptor decreased NRG-1 induced HER2 activation lower than control by 38% Finally, HER2 activation increased IL-6 secretion more than two-fold over resting cells (526 ± 131 vs 231 ± 39.7 pg/ml), and inhibition of HER2 gene expression decreased basal IL-6 secretion over 80% (89 + 4.6 vs 1.3 + 0.8 pg/ml). These findings identify a requirement for IL-6 and the IL-6R complex to allow NRG-1 mediated HER2 activation, and a HER2 driven IL-6 production feedback loop.

The relationship between self-report and performance-based measures of physical function following an ICU stay

PURPOSE

To examine relationships between self-report and performance-based measures of physical function in ICU patients randomized to standardized rehabilitation therapy (SRT) or usual care (UC).

METHODS

Physical function was assessed in 257 ICU patients using self-report (physical functioning scale of the SF-36 (SF-36 PFS)) and the functional performance inventory-short form (FPI-SF) as well as performance-based measures (Short Physical Performance Battery (SPPB)) and muscular strength (MS). Assessments were at hospital discharge, 2, 4, and 6 months.

RESULTS

Correlations between self-report and performance-based measures were not significantly different between the two groups. When examining the entire cohort, a significant, but weak, correlation (r = 0.286) was found between the SF-36 PFS and the SPPB. At 2 months, moderate correlations were found between self-report and performance-based measures. The SF-36 PFS and FPI were significantly correlated with the SPPB (r = 0.536 and 0.553, respectively) and muscular strength (r = 0.413 and 0.431, respectively). Similar associations were seen at 4 and 6 months in both groups.

CONCLUSION

Self-report and performance-based measures of physical function appear to assess different constructs at hospital discharge. Following recovery, these measures converge, but indicate different constructs are being assessed. As such, both self-report and performance-based measures of physical function should be used with ICU patients.

Therapeutic bronchoscopy vs. standard of care in acute respiratory failure: a systematic review

BACKGROUND

We aimed to assess patient-important benefits and harms of therapeutic bronchoscopy vs. standard of care (no bronchoscopy) in critically ill patients with acute respiratory failure (ARF).

METHODS

We conducted a systematic review with meta-analysis and trial sequential analysis (TSA) according to the Cochrane Handbook and GRADE methodology, including a predefined protocol (PROSPERO no. CRD42016046235). We included randomized clinical trials (RCTs) comparing therapeutic bronchoscopy to standard of care in critically ill patients with ARF. Two reviewers independently assessed trials for inclusion, extracted data and assessed risk of bias. Risk ratios (RR) with 95% confidence intervals (CI) were estimated by conventional meta-analysis. The risk of random errors was assessed by TSA. Exclusively patient-important outcomes were evaluated.

RESULTS

We included five trials (n = 212); all were judged as having high risk of bias. There was no difference in all-cause mortality between therapeutic bronchoscopy and standard of care (TSA adjusted RR 0.39; 95% CI 0.14 to 1.07; I² 0%), and only 3% of the required information size had been accrued. There was no difference in ICU length of stay. A shorter duration of mechanical ventilation was suggested by conventional meta-analysis, however TSA highlighted that only 42% of the required information size had been accrued, indicating high risk of random errors. No trials reported data on adverse events, hospital length of stay, quality of life or performance status.

CONCLUSIONS

The quantity and quality of evidence supporting therapeutic bronchoscopy in critically ill patients with ARF is very low with no firm evidence for benefit or harm.

[Dexmedetomidine preconditioning protects against lipopolysaccharides-induced injury in the human alveolar epithelial cells]

BACKGROUND AND OBJECTIVES

Dexmedetomidine (DEX) has demonstrated the preconditioning effect and shown protective effects against organize injury. In this study, using A549 (human alveolar epithelial cell) cell lines, we investigated whether DEX preconditioning protected against acute lung injury (ALI) in vitro.

METHODS

A549 were randomly divided into four groups (n=5): control group, DEX group, lipopolysaccharides (LPS) group, and D-LPS (DEX+LPS) group. Phosphate buffer saline (PBS) or DEX were administered. After 2h preconditioning, the medium was refreshed and the cells were challenged with LPS for 24h on the LPS and D-LPS group. Then the malondialdehyde (MDA), superoxide dismutase (SOD), Bcl-2, Bax, caspase-3 and the cytochrome c in the A549 were tested. The apoptosis was also evaluated in the cells.

RESULTS

Compare with LPS group, DEX preconditioning reduced the apoptosis (26.43%±1.05% vs. 33.58%±1.16%, p<0.05) in the A549, which is correlated with decreased MDA (12.84±1.05 vs. 19.16±1.89nmol.mg^-1 protein, p<0.05) and increased SOD activity (30.28±2.38 vs. 20.86±2.19U.mg^-1 protein, p<0.05). DEX preconditioning also increased the Bcl-2 level (0.53±0.03 vs. 0.32±0.04, p<0.05) and decreased the level of Bax (0.49±0.04 vs. 0.65±0.04, p<0.05), caspase-3 (0.54±0.04 vs. 0.76±0.04, p<0.05) and cytochrome c.

CONCLUSION

DEX preconditioning has a protective effect against ALI in vitro. The potential mechanisms involved are the inhibition of cell death and improvement of antioxidation.

Effects of N-acetylcysteine treatment in acute respiratory distress syndrome: A meta-analysis

Acute respiratory distress syndrome (ARDS) is a serious complication of acute lung injury. Severe systemic inflammation is the main cause of multiple organ dysfunction and high mortality. Removal of reactive oxygen species by anti-oxidants has been applied in clinical practice. N-acetylcysteine (NAC) is the most commonly used anti-oxidant. However, the benefit of anti-oxidant therapy was not consistently demonstrated by previous studies. In the present study, a meta-analysis was performed to evaluate the effects of NAC for adult patients with ARDS. The PubMed, Cochrane and EMBASE databases were searched to retrieve all of the available randomized controlled trials (RCTs) published until October 2015. Quality evaluation of included studies was performed according to the modified Jadad scale score. The Cochrane Collaboration Review Manager 5.3 software was used to perform the meta-analysis. Five RCTs comprising 183 patients were found to be eligible for inclusion in the meta-analysis. Pooled analysis showed that NAC did not contribute to reduce short-term mortality [risk ratio (RR)=0.73; 95% confidence interval (CI): 0.50–1.07; P=0.10] or 30-day mortality (RR=0.72; 95% CI: 0.44–1.19; P=0.20) when compared with those in the control group. However, duration of intensive care unit (ICU) stay in the NAC group was shortened [weighted mean difference (WMD), −4.56; 95% CI: (−7.32 to −1.80); P=0.001]. There was no significant difference in the ratio of partial arterial oxygen pressure to the fraction of inspired oxygen between the two groups [WMD, 54.34; 95% CI: (−30.50 to 139.17); P=0.21]. No severe adverse reactions were observed in the patients included. Although the duration of ICU stay was shortened, the clinical benefits of NAC were limited for ARDS based on the present meta-analysis. As the number of included trials and patients was small, additional trials are required to provide sufficient evidence for the efficacy of NAC in ARDS.

Primary Outcome Measures in Pediatric Septic Shock Trials: A Systematic Review

OBJECTIVE

To evaluate all published pediatric randomized controlled trials of patients with septic shock from any cause to examine the outcome measures used, the strengths and limitations of these measurements and whether the trial outcomes met feasibility criteria.

DATA SOURCES

We used a previously published database of pediatric critical care randomized controlled trials (PICUtrials.net) derived from searches of MEDLINE, EMBASE, LILACS, and CENTRAL.

STUDY SELECTION

We included randomized controlled trials of interventions to children admitted to a PICU with septic or dengue hemorrhagic shock which were published in English.

DATA EXTRACTION

Study characteristics and outcomes were retrieved by two independent reviewers with disagreement being resolved by a third reviewer. We defined feasibility as 1) recruitment of at least 90% of the targeted sample size and agreement of the observed outcome rate in the control group with the rate used for the sample size calculation to within 10% or 2) finding of a statistically significant difference in an interim or final analysis.

DATA SYNTHESIS

Nineteen of 321 identified articles were selected for review. Fourteen of 19 studies (74%) provided an a priori definition of their primary outcome measure in their "Methods section." Mortality rate was the most commonly reported primary outcome (8/14; 57%), followed by duration of shock (4/14; 29%) followed by organ failure (1/14; 7%). Only three of 19 included trials met feasibility criteria.

CONCLUSIONS

Our review found that use of mortality alone as a primary outcome in pediatric septic shock trials was associated with significant limitations and that long-term patient-centered outcomes were not used in this setting. Composite outcomes incorporating mortality and long-term outcomes should be explored for use in future pediatric septic shock trials.

Circulating chromogranin B levels in patients with acute respiratory failure: data from the FINNALI Study

PURPOSE

Circulating chromogranin B (CgB) levels are increased in situations characterized by systemic and myocardial stress, but whether CgB provides prognostic information in patients with acute respiratory failure (ARF) is unknown.

METHODS

We included 584 patients with ARF, defined as ventilatory support >6 h, and with blood samples available on Intensive Care Unit (ICU) admission and day 3 (n = 479). CgB levels were measured by radioimmunoassay and follow-up was 90 days.

RESULTS

One-hundred-sixty-nine patients (29%) died during follow-up. Admission CgB levels separated non-survivors from survivors: median 1234 (Q1-3 989-1742) vs. 917 (753-1224) pmol/L, respectively, p < 0.001. CgB levels on ICU admission (logarithmically transformed) were associated with time to death after adjustment for established risk indices available on ICU admission, including N-terminal pro-B-type natriuretic levels: HR 2.62 (95%C.I. 1.82-3.77), p < 0.001. Admission CgB levels also improved prognostication on top of SOFA and SAPS II scores as assessed by Cox regression analyses and the category-free net reclassification index. The area under the curve (AUC) for admission CgB levels to separate survivors and non-survivors was 0.72 (95%CI 0.67-0.76), while the AUC on day 3 was 0.60 (0.54-0.66).

CONCLUSIONS

CgB levels measured on ICU admission provided additional prognostic information to established risk indices in ARF patients.

High flow nasal cannula versus conventional oxygen therapy and non-invasive ventilation in adults with acute hypoxemic respiratory failure: A systematic review

INTRODUCTION

Humidified oxygen via a high flow nasal cannula (HFNC) is a form of supplemental oxygen therapy that has significant theoretical advantages over conventional oxygen therapy (COT). However, the clinical role of HFNC in acute hypoxemic respiratory failure (AHRF) has not been well established. This review compares the efficacy of HFNC with COT and non-invasive ventilation (NIV) in patients with AHRF.

METHODS

Studies reviewed were selected based on relevance from a systematic literature search conducted in Medline and EMBASE to include all published original research through May 2016. Twelve studies matched the inclusion criteria.

RESULTS

In the majority of the studies, HFNC was associated with superior comfort and patient tolerance as compared to NIV or COT. HFNC was associated with reduced work of breathing in comparison with COT in some, but not all, studies in the review. COT and NIV were associated with a higher 90-day mortality rate compared to HFNC in only one multicenter randomized trial versus no mortality difference reported by others. Three out of four studies demonstrated a decreased need for escalation of oxygen therapy with HFNC. Six out of eight studies demonstrated improved oxygenation with HFNC as compared to COT. Two of three studies revealed worse oxygenation with HFNC as compared to NIV.

CONCLUSION

This review suggests that HFNC may be superior to COT in AHRF patients in terms of oxygenation, patient comfort, and work of breathing. It may be reasonable to consider HFNC as an intermediate level of oxygen therapy between COT and NIV.

Prognostic Value of Secretoneurin in Patients with Acute Respiratory Failure: Data from the FINNALI Study

BACKGROUND

We examined whether secretoneurin (SN), a biomarker associated with cardiomyocyte Ca2+ handling, provides prognostic information in patients with acute respiratory failure (ARF).

METHODS

We included 490 patients with ARF, defined as ventilatory support &gt;6 h, with blood samples available on admission to the intensive care unit (ICU). SN concentrations were measured by RIA.

RESULTS

A total of 209 patients (43%) were hospitalized with cardiovascular (CV)-related ARF, and 90-day mortality rates were comparable between CV- and non–CV-related ARF (n = 281): 31% vs 24%, P = 0.11. Admission SN concentrations were higher in nonsurvivors than in survivors in both CV-related (median 148 [quartile 1–3, 117–203] vs 108 [87–143] pmol/L, P &lt; 0.001) and non–CV-related ARF (139 [115–184] vs 113 [91–139] pmol/L, P &lt; 0.001). In patients with CV-related ARF, SN concentrations on ICU admission were associated with 90-day mortality [odds ratio (OR) 1.97 (95% CI, 1.04–3.73, P = 0.04)] after adjusting for established risk indices, including N-terminal-pro-B-type natriuretic peptide (NT-proBNP) concentrations. SN also improved patient classification in CV-related ARF as assessed by the net reclassification index: 0.32 (95% CI, 0.04–0.59), P = 0.03. The area under the curve (AUC) of SN to predict mortality in patients with CV-related ARF was 0.72 (95% CI, 0.65–0.79), and the AUC of NT-proBNP was 0.64 (0.56–0.73). In contrast, SN concentrations on ICU admission did not provide incremental prognostic value to established risk indices in patients with non–CV-related ARF, and the AUC was 0.67 (0.60–0.75).

CONCLUSIONS

SN concentrations measured on ICU admission provided incremental prognostic information to established risk indices in patients with CV-related ARF, but not in patients with non–CV-related ARF.

Inhibition of EphA2/EphrinA1 signal attenuates lipopolysaccharide-induced lung injury

Eph-Ephrin signalling mediates various cellular processes, including vasculogenesis, angiogenesis, cell migration, axon guidance, fluid homoeostasis and repair after injury. Although previous studies have demonstrated that stimulation of the EphA receptor induces increased vascular permeability and inflammatory response in lung injury, the detailed mechanisms of EphA2 signalling are unknown. In the present study, we evaluated the role of EphA2 signalling in mice with lipopolysaccharide (LPS)-induced lung injury. Acute LPS exposure significantly up-regulated EphA2 and EphrinA1 expression. Compared with LPS+IgG mice (IgG instillation after LPS exposure), LPS+EphA2 mAb mice [EphA2 monoclonal antibody (mAb) instillation posttreatment after LPS exposure] had attenuated lung injury and reduced cell counts and protein concentration of bronchoalveolar lavage fluid (BALF). EphA2 mAb posttreatment down-regulated the expression of phosphoinositide 3-kinases (PI3K) 110γ, phospho-Akt, phospho-NF-κB p65, phospho-Src and phospho-S6K in lung lysates. In addition, inhibiting the EphA2 receptor augmented the expression of E-cadherin, which is involved in cell-cell adhesion. Our study identified EphA2 receptor as an unrecognized modulator of several signalling pathways-including PI3K-Akt-NF-kB, Src-NF-κB, E-cadherin and mTOR-in LPS-induced lung injury. These results suggest that EphA2 receptor inhibitors may function as novel therapeutic agents for LPS-induced lung injury.

Acute respiratory compromise on inpatient wards in the United States: Incidence, outcomes, and factors associated with in-hospital mortality

AIM

To estimate the United States' incidence and in-hospital mortality of acute respiratory events on inpatient wards and to identify factors associated with mortality.

METHODS

This is an analysis of prospectively collected data from the Get With the Guidelines(®) - Resuscitation registry. We included adult patients with index acute respiratory events on inpatient wards from January 2005 to December 2013. A negative binomial regression model was used to estimate the 2012 United States incidence and a multivariable logistic regression model was used to examine time trends and characteristics associated with in-hospital mortality.

RESULTS

There were 13,086 index events from 320 hospitals included in the analysis. Using 2012 data, the estimated number of events in the United States was 44,551 (95%CI: 25,170-95,371). The in-hospital mortality for the entire cohort was 39.4% (95%CI: 38.5, 40.2) and rose to 82.6% (95%CI: 79.9, 85.2) for events leading to cardiac arrest. There was a decrease in in-hospital mortality over time (48.3% in 2005 to 34.5% in 2013, p<0.001). Characteristics associated with mortality included agonal breathing, hypotension and septicemia.

CONCLUSIONS

Acute respiratory events on inpatient wards in the US is common with an associated in-hospital mortality of approximately 40% that has been decreasing over the past decade. Multiple factors were associated with in-hospital mortality.

Efficacy of non-invasive mechanical ventilation in the general ward in patients with chronic obstructive pulmonary disease admitted for hypercapnic acute respiratory failure and pH < 7.35: a feasibility pilot study

AIM

To date non-invasive (NIV) mechanical ventilation use is not recommended in chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF) and pH < 7.30 outside a 'protected environment'. We assessed NIV efficacy and feasibility in improving arterial blood gases (ABG) and in-hospital outcome in patients with ARF and severe respiratory acidosis (RA) admitted to an experienced rural medical ward.

METHODS

This paper is a prospective pilot cohort study conducted in the General Medicine Ward of Budrio's District Hospital. Two hundred and seventy-two patients with ARF were admitted to our Department, 112, meeting predefined inclusion criteria (pH < 7.35, PaCO2 > 45 mmHg). Patients were divided according to the severity of acidosis into: group A (pH < 7.26), group B (7.26 ≤ pH < 7.30) and group C (7.30 ≤ pH < 7.35). ABG were assessed at admission, at 2-6 h, 24 h, 48 h and at discharge.

RESULTS

Group A included 55 patients (24 men, mean age: 80.8 ± 8.3 years), group B 31 (12 men, mean age: 80.3 ± 9.4 years) and group C 26 (15 men, mean age: 78.6 ± 9.9 years). ABG improved within the first hours in 92/112 (82%) patients, who were all successfully discharged. Eighteen percent (20/112) of the patients died during the hospital stay, no significant difference emerged in mortality rate (MR) within the groups (23%, 16% and 8%, for groups A, B and C, respectively) and between patients with or without pneumonia: 8/29 (27%) versus 12/83 (14%). On multivariable analysis, only age and Glasgow Coma Scale had an impact on the clinical outcome.

CONCLUSION

In a non-'highly protected' environment such as an experienced medical ward of a rural hospital, NIV is effective not only in patients with mild, but also with severe forms of RA. MR did not vary according to the level of initial pH.

Yes-associated protein (YAP) signaling regulates lipopolysaccharide-induced tissue factor expression in human endothelial cells

BACKGROUND

Sepsis-induced acute lung injury (ALI) is characterized by fibrin deposition, which indicates the local activation of coagulation. Tissue factor (TF), expressed in the pulmonary microvasculature, acts as a critical initiator of blood coagulation and ALI in sepsis. The molecular mechanism of lipopolysaccharide (LPS)-induced TF expression in endothelial cells (ECs), however, has not been determined. In this study, we implicate the Rho-associated protein kinase (ROCK)/Yes associated protein (YAP)/early growth response (Egr-1) signaling pathway in LPS-induced TF expression in vitro and in sepsis-induced ALI in vivo.

METHODS

Human umbilical vein ECs incubated with LPS were pretreated with or without the ROCK inhibitor Y-27632, a YAP small, interfering RNA (siRNA) and an Egr-1 siRNA. ROCK, YAP and Egr-1 signaling-induced protein expression was investigated by Western blot. The LPS-induced activation of YAP was analyzed by an immunofluorescent assay. Furthermore, we intratracheally injected YAP siRNA to assess septic ALI in mice by hematoxylin and eosin staining.

RESULTS

LPS rapidly induced ROCK activation and increased TF expression in ECs. LPS caused YAP shuttling into the nuclei of ECs and combined with Egr-1 via the activation of ROCK. Furthermore, the LPS-mediated TF expression increase was prevented by ROCK inactivation, YAP knockdown and Egr-1 depletion, suggesting that LPS-induced TF expression is closely associated with the ROCK/YAP/Egr-1 signaling pathway in ECs. Finally, an intratracheal injection of YAP siRNA relieved lung injury in septic mice.

CONCLUSION

This study not only suggests that ROCK/YAP/Egr-1 signaling regulates TF expression after stimulation with LPS in ECs, but it also indicates that LPS-induced activation of YAP signaling plays an important role in septic ALI in mice. Our findings provide a new insight into the pathogenic mechanism of TF expression, which is closely linked to septic ALI, and YAP signaling is considered to be a novel target for therapeutic intervention under septic conditions.

Association between prehospital vitamin D status and incident acute respiratory failure in critically ill patients: a retrospective cohort study

Objective

We hypothesise that low 25-hydroxyvitamin D (25(OH)D) levels before hospitalisation are associated with increased risk of acute respiratory failure.

Design

Retrospective cohort study.

Setting

Medical and Surgical Intensive care units of two Boston teaching hospitals.

Patients

1985 critically ill adults admitted between 1998 and 2011.

Interventions

None.

Measurements and main results

The exposure of interest was prehospital serum 25(OH)D categorised as ≤10 ng/mL, 11–19.9 ng/mL, 20–29.9 ng/mL and ≥30 ng/mL. The primary outcome was acute respiratory failure excluding congestive heart failure determined by International Classification of Diseases Ninth Edition (ICD-9) coding and validated against the Berlin Definition of acute respiratory sistress syndrome. Association between 25(OH)D and acute respiratory failure was assessed using logistic regression, while adjusting for age, race, sex, Deyo-Charlson Index and patient type (medical vs surgical).

In the cohort, the mean age was 63 years, 45% were male and 80% were white; 25(OH)D was ≤10 ng/mL in 8% of patients, 11–19.9 ng/mL in 24%, 20–29.9 ng/mL in 24% and ≥30 ng/mL in 44% of patients. Eighteen per cent (n=351) were diagnosed with acute respiratory failure. Compared to patients with 25(OH)D ≥30 ng/mL, patients with lower 25(OH)D levels had significantly higher adjusted odds of acute respiratory failure (≤10 ng/mL, OR=1.84 (95% CI 1.22 to 2.77); 11–19.9 ng/mL, OR=1.60 (95% CI 1.19 to 2.15); 20–29.9 ng/mL, OR=1.37 (95% CI 1.01 to 1.86)).

Conclusions

Prehospital 25(OH)D was associated with the risk of acute respiratory failure in our critically ill patient cohort.

JNK inhibitor SP600125 protects against lipopolysaccharide-induced acute lung injury via upregulation of claudin-4

Although in vitro studies have previously demonstrated that mitogen-activated protein kinases are important for the activation of transcription factors and the regulation of proinflammatory mediators, the function of c-Jun NH₂-terminal kinase (JNK) in acute lung injury (ALI) remains to be fully elucidated. The present study aimed to investigate the effect of the JNK selective inhibitor SP600125 on lipopolysaccharide (LPS)-induced ALI. Pulmonary edema, the expression of inflammatory cytokines and pathological alterations were found to be significantly attenuated in LPS-induced ALI following treatment with SP600125 in vivo. In vitro, it was demonstrated that SP600125 administration significantly improved A549 cell viability in a dose-dependent manner using the Cell Counting kit-8 and the 5-ethynyl-2'-deoxyuridine incorporation assay. Furthermore, flow cytometric analysis demonstrated that the apoptotic rate was significantly reduced in a concentration-dependent manner following SP600125 injection. At the molecular level, SP600125 treatment dose-dependently inhibited JNK activation and upregulated claudin-4 expression in vivo and in vitro. In combination, the results from the present study indicated that the JNK inhibitor SP600125 protected against LPS-induced ALI in vivo and in vitro, possibly by upregulating the expression of claudin-4.

Serum activin A and B levels predict outcome in patients with acute respiratory failure: a prospective cohort study

INTRODUCTION

30 day mortality in patients with Acute Respiratory Failure (ARF) is approximately 30%, defined as patients requiring ventilator support for more than 6 hours. Novel biomarkers are needed to predict patient outcomes and to guide potential future therapies. The activins A and B, members of the Transforming Growth Factor β family of proteins, and their binding protein, follistatin, have recently been shown to be important regulators of inflammation and fibrosis but no substantial data are available concerning their roles in ARF.

METHODS

Specific assays for activin A, B and follistatin were used and the results analyzed according to diagnostic groups as well as according to standard measures in intensive care. Multivariable logistic regression was used to create a model to predict death at 90 days and 12 months from the onset of the ARF.

RESULTS

Serum activin A and B were significantly elevated in most patients and in most of the diagnostic groups. Patients who had activin A and/or B concentrations above the reference maximum were significantly more likely to die in the 12 months following admission [either activin A or B above reference maximum: Positive Likelihood Ratio [LR+] 1.65 [95% CI 1.28-2.12, P = 0.00013]; both activin A and B above reference maximum: LR + 2.78 [95% CI 1.96-3.95, P < 0.00001]. The predictive model at 12 months had an overall accuracy of 80.2% [95% CI 76.6-83.3%].

CONCLUSIONS

The measurement of activin A and B levels in these patients with ARF would have assisted in predicting those at greatest risk of death. Given the existing data from animal studies linking high activin A levels to significant inflammatory challenges, the results from this study suggest that approaches to modulate activin A and B bioactivity should be explored as potential therapeutic agents.

Inhaled Nitric Oxide: A Review of the Action, Current Literature, and An Analysis of its Use in the NHS Today

Nitric oxide is a potent vasodilator which when inhaled causes dilatation in the pulmonary vasculature. It is this action that has been studied in intensive care medicine, especially in relation to hypoxic vasoconstriction associated with acute respiratory distress syndrome (ARDS). The use of inhaled nitric oxide has been shown to improve ventilation:perfusion matching, and thus to improve oxygenation. This article reviews the chemistry and clinical properties of nitric oxide as well as its potential uses, clinical effectiveness and side effects. The authors also surveyed UK intensive care units to review the current prevalence of the use of inhaled nitric oxide. It was found that while the majority do not currently use inhaled nitric oxide in ARDS patients, it had still been used in 27% (n=61) of the departments surveyed.

The utility of surgical lung biopsy in cancer patients with acute respiratory distress syndrome

Background

This retrospective study evaluated the utility and safety of surgical lung biopsy (SLB) in cancer patients with acute respiratory distress syndrome (ARDS).

Methods

All cases of critically ill patients with cancer and diagnosed with ARDS who underwent SLB in a tertiary care hospital from January 2002 to July 2009 were reviewed. Clinical data including patient baseline characteristics, surgical complications, pathological findings, treatment alterations, and survival outcomes were retrospectively collected and analyzed.

Results

A total of 16 critically ill patients with cancer diagnosed with ARDS who underwent SLB were enrolled. The meantime from ARDS onset to SLB was 3.0 ± 1.5 days. All SLB specimens offered a pathological diagnosis, and specific diagnoses were made in 9 of 16 patients. Biopsy findings resulted in a change in therapy in 11 of 16 patients. Overall, the SLB surgical complication rate was 19% (3/16). SLB did not directly cause the observed operative mortality. The ICU mortality rate was 38% (6/16). Patients who switched therapies after SLB had a trend toward decreased mortality than patients without a change in therapy (27% versus 60%; P = 0.299).

Conclusions

In selected critically ill cancer patients with ARDS, SLB had a high diagnostic yield rate and an acceptable surgical complication rate.

Epidemiology and outcomes of acute respiratory failure in the United States, 2001 to 2009: a national survey

BACKGROUND

The objective of this study was to evaluate trends in hospitalization, cost, and short-term outcomes in acute respiratory failure (ARF) between 2001 and 2009 in the United States.

METHODS

Using the Nationwide Inpatient Sample we identified cases of ARF based on International Classification for Diseases, Ninth Revision, Clinical Modification codes. We calculated weighted frequencies of ARF hospitalizations by year and estimated population-adjusted incidence and mortality rates. We used logistic regression to examine hospital mortality rates over time while adjusting for changes in demographic characteristics and comorbidities of patients.

RESULTS

The number of hospitalizations with a diagnosis of ARF rose from 1,007,549 in 2001 to 1,917,910 in 2009, with an associated increase in total hospital costs from $30.1 billion to $54.3 billion. During the same period we observed a decrease in hospital mortality from 27.6% in 2001 to 20.6% in 2009, a slight decline in average length of stay from 7.8 days to 7.1 days, and no significant change in the mean cost per case ($15,900). Rates of mechanical ventilation (noninvasive [NIV] or invasive mechanical ventilation [IMV]) remained stable over the 9-year period, and the use of NIV increased from 4% in 2001 to 10% in 2009.

CONCLUSIONS

Over the period of 2001 to 2009, there was a steady increase in the number of hospitalizations with a discharge diagnosis of ARF, with a decrease in inpatient mortality. There was a significant shift during this time toward the use of NIV, with a decrease in the rates of IMVuse.

Ventilatory strategies in septic patients. Results from a nationwide observational trial

BACKGROUND

Mortality in intensive care unit (ICU) patients is affected by multiple variables. The possible impact of the mode of ventilation has not yet been clarified; therefore, a secondary analysis of the "epidemiology of sepsis in Germany" study was performed. The aims were (1) to describe the ventilation strategies currently applied in clinical practice, (2) to analyze the association of the different modes of ventilation with mortality and (3) to investigate whether the ratio between arterial partial pressure of oxygen and inspired fraction of oxygen (PF ratio) and/or other respiratory variables are associated with mortality in septic patients needing ventilatory support.

METHODS

A total of 454 ICUs in 310 randomly selected hospitals participated in this national prospective observational 1-day point prevalence of sepsis study including 415 patients with severe sepsis or septic shock according to the American College of Chest Physicians/Society of Critical Care Medicine criteria.

RESULTS

Of the 415 patients, 331 required ventilatory support. Pressure controlled ventilation (PCV) was the most frequently used ventilatory mode (70.6 %) followed by assisted ventilation (AV 21.7 %) and volume controlled ventilation (VCV 7.7 %). Hospital mortality did not differ significantly among patients ventilated with PCV (57 %), VCV (71 %) or AV (51 %, p=0.23). A PF ratio equal or less than 300 mmHg was found in 83.2 % of invasively ventilated patients (n=316). In AV patients there was a clear trend to a higher PF ratio (204±70 mmHg) than in controlled ventilated patients (PCV 179±74 mmHg, VCV 175±75 mmHg, p=0.0551). Multiple regression analysis identified the tidal volume to pressure ratio (tidal volume divided by peak inspiratory airway pressure, odds ratio OR=0.94, 95 % confidence interval 95% CI=0.89-0.99), acute renal failure (OR=2.15, 95% CI=1.01-4.55) and acute physiology and chronic health evaluation (APACHE) II score (OR=1.09, 95% CI=1.03-1.15) but not the PF ratio (univariate analysis OR=0.998, 95 % CI=0.995-1.001) as independent risk factors for in-hospital mortality.

CONCLUSIONS

This representative survey revealed that severe sepsis or septic shock was frequently associated with acute lung injury. Different ventilatory modes did not affect mortality. The tidal volume to inspiratory pressure ratio but not the PF ratio was independently associated with mortality.

Lung injury prediction score for the emergency department: first step towards prevention in patients at risk

BACKGROUND

Early identification of patients at risk of developing acute lung injury (ALI) is critical for potential preventive strategies. We aimed to derive and validate an acute lung injury prediction score (EDLIPS) in a multicenter sample of emergency department (ED) patients.

METHODS

We performed a subgroup analysis of 4,361 ED patients enrolled in the previously reported multicenter observational study. ED risk factors and conditions associated with subsequent ALI development were identified and included in the EDLIPS model. Scores were derived and validated using logistic regression analyses. The model was assessed with the area under the receiver-operating curve (AUC) and compared to the original LIPS model (derived from a population of elective high-risk surgical and ED patients) and the Acute Physiology and Chronic Health Evaluation (APACHE II) score.

RESULTS

The incidence of ALI was 7.0% (303/4361). EDLIPS discriminated patients who developed ALI from those who did not with an AUC of 0.78 (95% CI 0.75, 0.82), better than the APACHE II AUC 0.70 (p ≤ 0.001) and similar to the original LIPS score AUC 0.80 (p = 0.07). At an EDLIPS cutoff of 5 (range -0.5, 15) positive and negative likelihood ratios (95% CI) for ALI development were 2.74 (2.43, 3.07) and 0.39 (0.30, 0.49), respectively, with a sensitivity 0.72(0.64, 0.78), specificity 0.74 (0.72, 0.76), and positive and negative predictive value of 0.18 (0.15, 0.21) and 0.97 (0.96, 0.98).

CONCLUSION

EDLIPS may help identify patients at risk for ALI development early in the course of their ED presentation. This novel model may detect at-risk patients for treatment optimization and identify potential patients for ALI prevention trials.

Gelam honey has a protective effect against lipopolysaccharide (LPS)-induced organ failure

Gelam honey exerts anti-inflammatory and antioxidant activities and is thought to have potent effects in reducing infections and healing wounds. The aim of this study was to investigate the effects of intravenously-injected Gelam honey in protecting organs from lethal doses of lipopolysaccharide (LPS). Six groups of rabbits (N = 6) were used in this study. Two groups acted as controls and received only saline and no LPS injections. For the test groups, 1 mL honey (500 mg/kg in saline) was intravenously injected into two groups (treated), while saline (1 mL) was injected into the other two groups (untreated); after 1 h, all four test groups were intravenously-injected with LPS (0.5 mg/kg). Eight hours after the LPS injection, blood and organs were collected from three groups (one from each treatment stream) and blood parameters were measured and biochemical tests, histopathology, and myeloperoxidase assessment were performed. For survival rate tests, rabbits from the remaining three groups were monitored over a 2-week period. Treatment with honey showed protective effects on organs through the improvement of organ blood parameters, reduced infiltration of neutrophils, and decreased myeloperoxidase activity. Honey-treated rabbits also showed reduced mortality after LPS injection compared with untreated rabbits. Honey may have a therapeutic effect in protecting organs during inflammatory diseases.

Acute respiratory distress syndrome and lung injury: Pathogenetic mechanism and therapeutic implication

To review possible mechanisms and therapeutics for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). ALI/ARDS causes high mortality. The risk factors include head injury, intracranial disorders, sepsis, infections and others. Investigations have indicated the detrimental role of nitric oxide (NO) through the inducible NO synthase (iNOS). The possible therapeutic regimen includes extracorporeal membrane oxygenation, prone position, fluid and hemodynamic management and permissive hypercapnic acidosis etc. Other pharmacological treatments are anti-inflammatory and/or antimicrobial agents, inhalation of NO, glucocorticoids, surfactant therapy and agents facilitating lung water resolution and ion transports. β-adrenergic agonists are able to accelerate lung fluid and ion removal and to stimulate surfactant secretion. In conscious rats, regular exercise training alleviates the endotoxin-induced ALI. Propofol and N-acetylcysteine exert protective effect on the ALI induced by endotoxin. Insulin possesses anti-inflammatory effect. Pentobarbital is capable of reducing the endotoxin-induced ALI. In addition, nicotinamide or niacinamide abrogates the ALI caused by ischemia/reperfusion or endotoxemia. This review includes historical retrospective of ALI/ARDS, the neurogenic pulmonary edema due to head injury, the detrimental role of NO, the risk factors, and the possible pathogenetic mechanisms as well as therapeutic regimen for ALI/ARDS.

CXCR4 regulates migration of lung alveolar epithelial cells through activation of Rac1 and matrix metalloproteinase-2

Restoration of the epithelial barrier following acute lung injury is critical for recovery of lung homeostasis. After injury, alveolar type II epithelial (ATII) cells spread and migrate to cover the denuded surface and, eventually, proliferate and differentiate into type I cells. The chemokine CXCL12, also known as stromal cell-derived factor 1α, has well-recognized roles in organogenesis, hematopoiesis, and immune responses through its binding to the chemokine receptor CXCR4. While CXCL12/CXCR4 signaling is known to be important in immune cell migration, the role of this chemokine-receptor interaction has not been studied in alveolar epithelial repair mechanisms. In this study, we demonstrated that secretion of CXCL12 was increased in the bronchoalveolar lavage of rats ventilated with an injurious tidal volume (25 ml/kg). We also found that CXCL12 secretion was increased by primary rat ATII cells and a mouse alveolar epithelial (MLE12) cell line following scratch wounding and that both types of cells express CXCR4. CXCL12 significantly increased ATII cell migration in a scratch-wound assay. When we treated cells with a specific antagonist for CXCR4, AMD-3100, cell migration was significantly inhibited. Knockdown of CXCR4 by short hairpin RNA (shRNA) caused decreased cell migration compared with cells expressing a nonspecific shRNA. Treatment with AMD-3100 decreased matrix metalloproteinase-14 expression, increased tissue inhibitor of metalloproteinase-3 expression, decreased matrix metalloproteinase-2 activity, and prevented CXCL12-induced Rac1 activation. Similar results were obtained with shRNA knockdown of CXCR4. These findings may help identify a therapeutic target for augmenting epithelial repair following acute lung injury.

Epidemiological features and risk factor analysis of children with acute lung injury

BACKGROUND

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) represents a devastating complication observed in critical care medicine. The purpose of this study is to investigate the epidemiological aspects of ALI/ARDS in pediatric intensive care unit (PICU) and risk factors of mortality.

METHODS

Patients with ALI/ARDS in PICU of Beijing Children's Hospital, a tertiary medical center from November 1, 2005 to October 31, 2006 were included in this prospective study. We identified the risk factors for underlying diseases and mortality during a 3-month followup using multivariate logistic regression analysis.

RESULTS

In 562 critically ill patients admitted to PICU of Beijing Children's Hospital, there were 15 ALI-non ARDS patients and 29 ARDS patients, resulting in an incidence of 7.8% (44/562). The mortality rate of ARDS was 24.1% (7/29) and that of ALI/ARDS was 18.2% (8/44). At a 3-month follow-up, 12 patients died after being discharged from PICU and the total mortality rate was 45.5% (20/44). ALI/ARDS patients with pulmonary disease had better outcomes than those with extra-pulmonary involvements (P<0.05). Discharge against medical advice, low PaO(2)/FiO(2) during hospital stay and high PaCO2 on PICU admission were risk factors of mortality.

CONCLUSIONS

ARDS has a high mortality rate in PICU, especially in those with extra-pulmonary diseases. In addition to aggressive medical management of comorbidity, lung protection and avoidance of discharge against medical advice will decrease the mortality.

The clinical differences between dengue and scrub typhus with acute respiratory failure in southern Taiwan

Background

For both dengue and scrub typhus, acute respiratory failure (ARF) is a serious complication. The present study was carried out in order to investigate the clinical courses and outcomes of adult dengue and scrub typhus patients with ARF, and to identify the clinical differences between adult dengue and scrub typhus patients with ARF.

Methods

We conducted a retrospective study of the serologically confirmed adult dengue or scrub typhus patients admitted between 1998 and 2008 at Kaohsiung Chang Gung Memorial Hospital. A total of 980 dengue and 102 scrub typhus adult patients were included in our study.

Results

Eighteen of the 980 adult dengue patients and 8 of the 102 adult scrub typhus patients had ARF. There were significant differences that existed for eschar (P = 0.001; dengue 0%; scrub 62.5%), cough (P = 0.016; dengue 55.6%; scrub typhus 100%), white blood cell (WBC) count [P = 0.026; dengue 7.40 ± 5.74; scrub typhus 11.84 ± 4.95 (×10³/μL)], platelet count [P = 0.008; dengue 42.2 ± 33.9; scrub typhus 104.1 ± 93.3 (×10⁹/L)], prothrombin time (PT) [P = 0.007; dengue 12.82 ± 1.36; scrub typhus 10.74 ± 0.98 (s)], activated partial thromboplastin time (APTT) [P = 0.002; dengue 50.81 ± 10.08; scrub typhus 37.44 ± 4.06 (s)], blood urea nitrogen (BUN) [P < 0.001; dengue 64.6 ± 43.2; scrub typhus 20.9 ± 9.1 (mg/dL)], creatinine [P < 0.001; dengue 3.77 ± 3.37; scrub typhus 1.05 ± 0.37 (mg/dL)], admission day (A-day) [P = 0.027; dengue 2.9 ± 1.3; scrub typhus 5.4 ± 2.6 (days)], and ventilator duration [P = 0.022; dengue 9.4 ± 14.0; scrub typhus 14.8 ± 10.4 (days)] between both groups.

Conclusions

This study provides relatively rare data regarding the clinical differences between adult dengue and scrub typhus patients with ARF.

Acute lung failure

Lung failure is the most common organ failure seen in the intensive care unit. The pathogenesis of acute respiratory failure (ARF) can be classified as (1) neuromuscular in origin, (2) secondary to acute and chronic obstructive airway diseases, (3) alveolar processes such as cardiogenic and noncardiogenic pulmonary edema and pneumonia, and (4) vascular diseases such as acute or chronic pulmonary embolism. This article reviews the more common causes of ARF from each group, including the pathological mechanisms and the principles of critical care management, focusing on the supportive, specific, and adjunctive therapies for each condition.

Short-term mortality prediction for acute lung injury patients: external validation of the Acute Respiratory Distress Syndrome Network prediction model

OBJECTIVE

An independent cohort of patients with acute lung injury was used to evaluate the external validity of a simple prediction model for short-term mortality previously developed using data from Acute Respiratory Distress Syndrome Network (ARDSNet) trials.

DESIGN

Data for external validation were obtained from a prospective cohort study of patients with acute lung injury.

SETTING

Thirteen intensive care units at four teaching hospitals in Baltimore, MD.

PATIENTS

Five hundred and eight nontrauma patients with acute lung injury.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 508 patients eligible for this analysis, 234 (46%) died inhospital. Discrimination of the ARDSNet prediction model for inhospital mortality, evaluated by the area under the receiver operator characteristic curves, was 0.67 for our external validation data set vs. 0.70 and 0.68 using Acute Physiology and Chronic Health Evaluation II and the ARDSNet validation data set, respectively. In evaluating calibration of the model, predicted vs. observed inhospital mortality for the external validation data set was similar for both low-risk (ARDSNet model score = 0) and high-risk (score = 3 or 4+) patient strata. However, for intermediate-risk (score = 1 or 2) patients, observed inhospital mortality was substantially higher than predicted mortality (25.3% vs. 16.5% and 40.6% vs. 31.0% for score = 1 and 2, respectively). Sensitivity analyses limiting our external validation data set to only those patients meeting the ARDSNet trial eligibility criteria and to those who received mechanical ventilation in compliance with the ARDSNet ventilation protocol did not substantially change the model's discrimination or improve its calibration.

CONCLUSIONS

Evaluation of the ARDSNet prediction model using an external acute lung injury cohort demonstrated similar discrimination of the model as was observed with the ARDSNet validation data set. However, there were substantial differences in observed vs. predicted mortality among intermediate-risk patients with acute lung injury. The ARDSNet model provided reasonable, but imprecise, estimates of predicted mortality when applied to our external validation cohort of patients with acute lung injury.

A porcine model for initial surge mechanical ventilator assessment and evaluation of two limited-function ventilators

OBJECTIVES

To adapt an animal model of acute lung injury for use as a standard protocol for a screening initial evaluation of limited function, or "surge," ventilators for use in mass casualty scenarios.

DESIGN

Prospective, experimental animal study.

SETTING

University research laboratory.

SUBJECTS

Twelve adult pigs.

INTERVENTIONS

Twelve spontaneously breathing pigs (six in each group) were subjected to acute lung injury/acute respiratory distress syndrome via pulmonary artery infusion of oleic acid. After development of respiratory failure, animals were mechanically ventilated with a limited-function ventilator (simplified automatic ventilator [SAVe] I or II; Automedx, Germantown, MD) for 1 hr or until the ventilator could not support the animal. The limited-function ventilator was then exchanged for a full-function ventilator (Servo 900C; Siemens-Elema, Solna, Sweden).

MEASUREMENTS AND MAIN RESULTS

Reliable and reproducible levels of acute lung injury/acute respiratory distress syndrome were induced. The SAVe I was unable to adequately oxygenate five animals with Pao2 (52.0±11.1 torr) compared to the Servo (106.0±25.6 torr; p=.002). The SAVe II was able to oxygenate and ventilate all six animals for 1 hr with no difference in Pao2 (141.8±169.3 torr) compared to the Servo (158.3±167.7 torr).

CONCLUSIONS

We describe a novel in vivo model of acute lung injury/acute respiratory distress syndrome that can be used to initially screen limited-function ventilators considered for mass respiratory failure stockpiles and that is intended to be combined with additional studies to definitively assess appropriateness for mass respiratory failure. Specifically, during this study we demonstrate that the SAVe I ventilator is unable to provide sufficient gas exchange, whereas the SAVe II, with several more functions, was able to support the same level of hypoxemic respiratory failure secondary to acute lung injury/acute respiratory distress syndrome for 1 hr.

Serum soluble triggering receptor expressed on myeloid cells-1 in acute respiratory distress syndrome: a prospective observational cohort study

Background/Purpose

Serum soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), a detector of acute inflammatory response to microbial products and a good marker for diagnosing sepsis and pneumonia, has not yet been described as a predictor for infection or a prognostic factor in patients with acute respiratory distress syndrome (ARDS).

Methods

This prospective observational cohort study enrolled 63 ventilated adult patients with ARDS; 50 as septic and 13 as non-septic, and followed them for 28 days in intensive care units at a university hospital in Taiwan. Serial serum sTREM-1 levels and cytokines, such as interleukin (IL)-1, IL-8, and tumor necrosis factor-α, on days 1, 3, 5, 7 and 14 were measured by an enzyme-linked immunosorbent assay. The association between biomarkers and clinical infectious diagnosis/outcome in ARDS was explored.

Results

Serum sTREM-1 and cytokine levels could not differentiate septic from non-septic ARDS. Serum log sTREM-1 and inflammatory cytokine levels were correlated positively (r = 0.325 for IL-1β; r = 0.247 for IL-8; r = 0.480 for tumor necrosis factor-α). As prognostic factors, higher serum sTREM-1 level on day 1 and increasing levels over time, especially in the first 5 days, were independent predictors of mortality on day 28, using a multivariate Cox regression model. Serum sTREM-1 levels remained stable or even increased in the non-surviving patients, but decreased in the survivors.

Conclusion

Serum sTREM-1 level might not be a reliable marker for infection in ARDS patients. However, as an inflammatory marker, initial serum sTREM-1 level and its trend over time, especially in the first 5 days, could be predictive of short-term mortality. A progressive decline in serum sTREM-1 levels during follow-up indicates a favorable outcome, whereas persistently elevated sTREM-1 indicates a poor prognosis and should lead to a re-evaluation of therapy.

Acute lung injury induces cardiovascular dysfunction: effects of IL-6 and budesonide/formoterol

Acute lung injury (ALI) is associated with systemic inflammation and cardiovascular dysfunction. IL-6 is a biomarker of this systemic response and a predictor of cardiovascular events, but its possible causal role is uncertain. Inhaled corticosteroids and long-acting β2 agonists (ICS/LABA) down-regulate the systemic expression of IL-6, but whether they can ameliorate the cardiovascular dysfunction related to ALI is uncertain. We sought to determine whether IL-6 contributes to the cardiovascular dysfunction related to ALI, and whether budesonide/formoterol ameliorates this process. Wild-type mice were pretreated for 3 hours with intratracheal budesonide, formoterol, or both, before LPS was sprayed into their tracheas. IL-6-deficient mice were similarly exposed to LPS. Four hours later, bronchoalveolar lavage fluid (BALF) and serum were collected, and endothelial and cardiac functions were measured, using wire myography of the aortic tissue and echocardiography, respectively. LPS significantly impaired vasodilatory responses to acetylcholine (P < 0.001) and cardiac output (P = 0.002) in wild-type but not IL-6-deficient mice. Intratracheal instillations of exogenous IL-6 into IL-6-deficient mice restored these impairments (vasodilatory responses to acetylcholine, P = 0.005; cardiac output, P = 0.025). Pretreatment with the combination of budesonide and formoterol, but not either alone, ameliorated the vasodilatory responses to acetylcholine (P = 0.018) and cardiac output (P < 0.001). These drugs also attenuated the rise in the systemic expression of IL-6 (P < 0.05) related to LPS. IL-6 contributes to the cardiovascular dysfunction related to LPS, and pretreatment with budesonide/formoterol reduces the systemic expression of IL-6 and improves cardiovascular dysfunction. ICS/LABA may reduce acute cardiovascular events related to ALI.