A user evaluation of speech/phrase recognition software in critically ill patients: a DECIDE-AI feasibility study

OBJECTIVES

Evaluating effectiveness of speech/phrase recognition software in critically ill patients with speech impairments.

DESIGN

Prospective study.

SETTING

Tertiary hospital critical care unit in the northwest of England.

PARTICIPANTS

14 patients with tracheostomies, 3 female and 11 male.

MAIN OUTCOME MEASURES

Evaluation of dynamic time warping (DTW) and deep neural networks (DNN) methods in a speech/phrase recognition application. Using speech/phrase recognition app for voice impaired (SRAVI), patients attempted mouthing various supported phrases with recordings evaluated by both DNN and DTW processing methods. Then, a trio of potential recognition phrases was displayed on the screen, ranked from first to third in order of likelihood.

RESULTS

A total of 616 patient recordings were taken with 516 phrase identifiable recordings. The overall results revealed a total recognition accuracy across all three ranks of 86% using the DNN method. The rank 1 recognition accuracy of the DNN method was 75%. The DTW method had a total recognition accuracy of 74%, with a rank 1 accuracy of 48%.

CONCLUSION

This feasibility evaluation of a novel speech/phrase recognition app using SRAVI demonstrated a good correlation between spoken phrases and app recognition. This suggests that speech/phrase recognition technology could be a therapeutic option to bridge the gap in communication in critically ill patients.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC

Communication can be attempted using visual charts, eye gaze boards, alphabet boards, speech/phrase reading, gestures and speaking valves in critically ill patients with speech impairments.

WHAT THIS STUDY ADDS

Deep neural networks and dynamic time warping methods can be used to analyse lip movements and identify intended phrases.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE AND POLICY

Our study shows that speech/phrase recognition software has a role to play in bridging the communication gap in speech impairment.

Sugar or salt ("SOS"): A protocol for a UK multicentre randomised trial of mannitol and hypertonic saline in severe traumatic brain injury and intracranial hypertension

Hyperosmolar solutions are widely used to treat raised intracranial pressure following severe traumatic brain injury. Although mannitol has historically been the most frequently administered, hypertonic saline solutions are increasingly being used. However, definitive evidence regarding their comparative effectiveness is lacking. The Sugar or Salt Trial is a UK randomised, allocation concealed open label multicentre pragmatic trial designed to determine the clinical and cost-effectiveness of hypertonic saline compared with mannitol in the management of patients with severe traumatic brain injury. Patients requiring intensive care unit admission and intracranial pressure monitoring post-traumatic brain injury will be allocated at random to receive equi-osmolar boluses of either mannitol or hypertonic saline following failure of routine first-line measures to control intracranial pressure. The primary outcome for the study will be the Extended Glasgow Outcome Scale assessed at six months after randomisation. Results will inform current clinical practice in the routine use of hyperosmolar therapy as well as assess the impact of potential side effects. Pre-planned longer term clinical and cost effectiveness analyses will further inform the use of these treatments.

Aspirin reduces lipopolysaccharide-induced pulmonary inflammation in human models of ARDS

RATIONALE

Platelets play an active role in the pathogenesis of acute respiratory distress syndrome (ARDS). Animal and observational studies have shown aspirin's antiplatelet and immunomodulatory effects may be beneficial in ARDS.

OBJECTIVE

To test the hypothesis that aspirin reduces inflammation in clinically relevant human models that recapitulate pathophysiological mechanisms implicated in the development of ARDS.

METHODS

Healthy volunteers were randomised to receive placebo or aspirin 75  or 1200 mg (1:1:1) for seven days prior to lipopolysaccharide (LPS) inhalation, in a double-blind, placebo-controlled, allocation-concealed study. Bronchoalveolar lavage (BAL) was performed 6 hours after inhaling 50 µg of LPS. The primary outcome measure was BAL IL-8. Secondary outcome measures included markers of alveolar inflammation (BAL neutrophils, cytokines, neutrophil proteases), alveolar epithelial cell injury, systemic inflammation (neutrophils and plasma C-reactive protein (CRP)) and platelet activation (thromboxane B2, TXB2). Human lungs, perfused and ventilated ex vivo (EVLP) were randomised to placebo or 24 mg aspirin and injured with LPS. BAL was carried out 4 hours later. Inflammation was assessed by BAL differential cell counts and histological changes.

RESULTS

In the healthy volunteer (n=33) model, data for the aspirin groups were combined. Aspirin did not reduce BAL IL-8. However, aspirin reduced pulmonary neutrophilia and tissue damaging neutrophil proteases (Matrix Metalloproteinase (MMP)-8/-9), reduced BAL concentrations of tumour necrosis factor α and reduced systemic and pulmonary TXB2. There was no difference between high-dose and low-dose aspirin. In the EVLP model, aspirin reduced BAL neutrophilia and alveolar injury as measured by histological damage.

CONCLUSIONS

These are the first prospective human data indicating that aspirin inhibits pulmonary neutrophilic inflammation, at both low and high doses. Further clinical studies are indicated to assess the role of aspirin in the prevention and treatment of ARDS.

TRIAL REGISTRATION NUMBER

NCT01659307 Results.

Simvastatin for patients with acute respiratory distress syndrome: long-term outcomes and cost-effectiveness from a randomised controlled trial

Background

Simvastatin therapy for patients with acute respiratory distress syndrome (ARDS) has been shown to be safe and associated with minimal adverse effects, but it does not improve clinical outcomes. The aim of this research was to report on mortality and cost-effectiveness of simvastatin in patients with ARDS at 12 months.

Methods

This was a cost-utility analysis alongside a multicentre, double-blind, randomised controlled trial carried out in the UK and Ireland. Five hundred and forty intubated and mechanically ventilated patients with ARDS were randomly assigned (1:1) to receive once-daily simvastatin (at a dose of 80 mg) or identical placebo tablets enterally for up to 28 days.

Results

Mortality was lower in the simvastatin group (31.8%, 95% confidence interval (CI) 26.1–37.5) compared to the placebo group (37.3%, 95% CI 31.6–43.0) at 12 months, although this was not significant. Simvastatin was associated with statistically significant quality-adjusted life year (QALY) gain (incremental QALYs 0.064, 95% CI 0.002–0.127) compared to placebo. Simvastatin was also less costly (incremental total costs –£3601, 95% CI –8061 to 859). At a willingness-to-pay threshold of £20,000 per QALY, the probability of simvastatin being cost-effective was 99%. Sensitivity analyses indicated that the results were robust to changes in methodological assumptions with the probability of cost-effectiveness never dropping below 90%.

Conclusion

Simvastatin was found to be cost-effective for the treatment of ARDS, being associated with both a significant QALY gain and a cost saving. There was no significant reduction in mortality at 12 months,

Trial registration

ISRCTN, 88244364. Registered 26 November 2010.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1695-0) contains supplementary material, which is available to authorized users.

pRotective vEntilation with veno-venouS lung assisT in respiratory failure: A protocol for a multicentre randomised controlled trial of extracorporeal carbon dioxide removal in patients with acute hypoxaemic respiratory failure

One of the few interventions to demonstrate improved outcomes for acute hypoxaemic respiratory failure is reducing tidal volumes when using mechanical ventilation, often termed lung protective ventilation. Veno-venous extracorporeal carbon dioxide removal (vv-ECCO₂R) can facilitate reducing tidal volumes. pRotective vEntilation with veno-venouS lung assisT (REST) is a randomised, allocation concealed, controlled, open, multicentre pragmatic trial to determine the clinical and cost-effectiveness of lower tidal volume mechanical ventilation facilitated by vv-ECCO₂R in patients with acute hypoxaemic respiratory failure. Patients requiring intubation and mechanical ventilation for acute hypoxaemic respiratory failure will be randomly allocated to receive either vv-ECCO₂R and lower tidal volume mechanical ventilation or standard care with stratification by recruitment centre. There is a need for a large randomised controlled trial to establish whether vv-ECCO₂R in acute hypoxaemic respiratory failure can allow the use of a more protective lung ventilation strategy and is associated with improved patient outcomes.

Mesenchymal stromal cells for treatment of the acute respiratory distress syndrome: The beginning of the story

In spite of decades of research, the acute respiratory distress syndrome (ARDS) continues to have an unacceptably high mortality and morbidity. Mesenchymal stromal cells (MSCs) present a promising candidate for the treatment of this condition and have demonstrated benefit in preclinical models. MSCs, which are a topic of growing interest in many inflammatory disorders, have already progressed to early phase clinical trials in ARDS. While a number of their mechanisms of effect have been elucidated, a better understanding of the complex actions of these cells may pave the way for MSC modifications, which might enable more effective translation into clinical practice.

Beta-Agonist Lung injury TrIal-2 (BALTI-2): a multicentre, randomised, double-blind, placebo-controlled trial and economic evaluation of intravenous infusion of salbutamol versus placebo in patients with acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a major cause of mortality in intensive care patients and lacks effective treatments. A previous randomised controlled Phase II trial suggested that an intravenous (i.v.) infusion of salbutamol may be beneficial, as it reduced extravascular lung water and plateau airway pressure. The Beta-Agonist Lung injury TrIal-2 (BALTI-2) was initiated to evaluate the effects of this intervention on mortality in patients with ARDS.

OBJECTIVES

To evaluate whether or not, in patients with ARDS, an i.v. infusion of salbutamol given at 15 μg/kg ideal body weight (IBW)/hour for up to 7 days, compared with a placebo (0.9% sodium chloride) infusion, reduces 28-day all-cause mortality and other clinical outcomes. To evaluate salbutamol's clinical effectiveness and its cost-effectiveness in subgroups of patients.

DESIGN

A multicentre, randomised, placebo-controlled trial.

SETTING

Forty-six intensive care units (ICUs) in the UK.

PARTICIPANTS

Patients were eligible if they (1) were intubated and mechanically ventilated patients in participating ICUs; (2) were within 72 hours of onset of ARDS; (3) fulfilled American-European Consensus Conference definition for ARDS {acute-onset, severe hypoxaemic respiratory failure [partial pressure of oxygen in arterial blood/fraction of inspired oxygen ≤ 26.7 kPa (200 mmHg)] and bilateral infiltrates on the chest radiograph in the absence of clinical evidence of left atrial hypertension}; and (4) were aged ≥ 16 years.

INTERVENTIONS

Intravenous infusion of salbutamol (15 μg/kg IBW/hour) or placebo (0.9% saline) for up to 7 days.

MAIN OUTCOME MEASURES

All-cause mortality 28 days after randomisation, mortality at (first) discharge from ICU, mortality at (first) discharge from hospital, number of ventilator-free days, number of organ failure-free days, mortality at 12 months post randomisation, side effects (tachycardia/new arrhythmia/lactic acidosis) sufficient to stop treatment with trial drug, health-related quality of life (European Quality of Life-5 Dimensions and Short Form questionnaire-12 items at 6 and 12 months after randomisation), length of stay in critical care unit and length of stay in hospital.

RESULTS

Forty-six ICUs recruited patients to the trial. A total of 326 patients were randomised; 162 were allocated to salbutamol and 164 to placebo. One patient in each group withdrew consent. Recruitment was stopped after the second interim analysis because of safety concerns. Salbutamol increased 28-day mortality: 55 (34%) of 161 patients died in the salbutamol group compared with 38 (23%) of 163 in the placebo group (risk ratio 1.47, 95% confidence interval 1.03 to 2.08).

CONCLUSIONS

Treatment with i.v. salbutamol early in the course of ARDS was poorly tolerated, is unlikely to be beneficial and could worsen outcomes. Further trials of β-agonists in patients with ARDS are unlikely to be conducted. Some questions remain, such as whether or not there may be benefit at a different dose or in specific populations, but any studies investigating these would require a very strong rationale.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN38366450.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Clinical grade allogeneic human mesenchymal stem cells restore alveolar fluid clearance in human lungs rejected for transplantation

The lack of suitable donors for all solid-organ transplant programs is exacerbated in lung transplantation by the low utilization of potential donor lungs, due primarily to donor lung injury and dysfunction, including pulmonary edema. The current studies were designed to determine if intravenous clinical-grade human mesenchymal stem (stromal) cells (hMSCs) would be effective in restoring alveolar fluid clearance (AFC) in the human ex vivo lung perfusion model, using lungs that had been deemed unsuitable for transplantation and had been subjected to prolonged ischemic time. The human lungs were perfused with 5% albumin in a balanced electrolyte solution and oxygenated with continuous positive airway pressure. Baseline AFC was measured in the control lobe and if AFC was impaired (defined as <10%/h), the lungs received either hMSC (5 × 10(6) cells) added to the perfusate or perfusion only as a control. AFC was measured in a different lung lobe at 4 h. Intravenous hMSC restored AFC in the injured lungs to a normal level. In contrast, perfusion only did not increase AFC. This positive effect on AFC was reduced by intrabronchial administration of a neutralizing antibody to keratinocyte growth factor (KGF). Thus, intravenous allogeneic hMSCs are effective in restoring the capacity of the alveolar epithelium to remove alveolar fluid at a normal rate, suggesting that this therapy may be effective in enhancing the resolution of pulmonary edema in human lungs deemed clinically unsuitable for transplantation.

Combined dysfunctions of immune cells predict nosocomial infection in critically ill patients

BACKGROUND

Nosocomial infection occurs commonly in intensive care units (ICUs). Although critical illness is associated with immune activation, the prevalence of nosocomial infections suggests concomitant immune suppression. This study examined the temporal occurrence of immune dysfunction across three immune cell types, and their relationship with the development of nosocomial infection.

METHODS

A prospective observational cohort study was undertaken in a teaching hospital general ICU. Critically ill patients were recruited and underwent serial examination of immune status, namely percentage regulatory T-cells (Tregs), monocyte deactivation (by expression) and neutrophil dysfunction (by CD88 expression). The occurrence of nosocomial infection was determined using pre-defined, objective criteria.

RESULTS

Ninety-six patients were recruited, of whom 95 had data available for analysis. Relative to healthy controls, percentage Tregs were elevated 6-10 days after admission, while monocyte HLA-DR and neutrophil CD88 showed broader depression across time points measured. Thirty-three patients (35%) developed nosocomial infection, and patients developing nosocomial infection showed significantly greater immune dysfunction by the measures used. Tregs and neutrophil dysfunction remained significantly predictive of infection in a Cox hazards model correcting for time effects and clinical confounders {hazard ratio (HR) 2.4 [95% confidence interval (CI) 1.1-5.4] and 6.9 (95% CI 1.6-30), respectively, P=0.001}. Cumulative immune dysfunction resulted in a progressive risk of infection, rising from no cases in patients with no dysfunction to 75% of patients with dysfunction of all three cell types (P=0.0004).

CONCLUSIONS

Dysfunctions of T-cells, monocytes, and neutrophils predict acquisition of nosocomial infection, and combine additively to stratify risk of nosocomial infection in the critically ill.

Matrix metalloproteinases in acute lung injury: mediators of injury and drivers of repair

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) comprise a spectrum of acute inflammatory pulmonary oedema resulting in refractory hypoxaemia in the absence of an underlying cardiogenic cause. There are multiple pulmonary and extrapulmonary causes and ALI/ARDS patients are a clinically heterogeneous group with associated high morbidity and mortality. Inflammatory injury to the alveolar epithelial and endothelial capillary membrane is a central event in the pathogenesis of ALI/ARDS, and involves degradation of the basement membrane. Matrix metalloproteinases (MMPs) have been implicated in a wide variety of pulmonary pathologies and are capable of degrading all components of the extracellular matrix including the basement membrane and key non-matrix mediators of lung injury such as chemokines and cell surface receptors. While many studies implicate MMPs in the injurious process, there are significant gaps in our knowledge of the role of specific proteases at different phases of injury and repair. This article examines the role of MMPs in injury and repair of the alveolar epithelial-endothelial capillary barrier and discusses the potential for MMP modulation in the prevention and treatment of ALI. The need for further mechanistic and in vivo studies to inform appropriate subsequent clinical trials of MMP modulation will be highlighted.

The Swine Flu Triage (SwiFT) study: development and ongoing refinement of a triage tool to provide regular information to guide immediate policy and practice for the use of critical care services during the H1N1 swine influenza pandemic

OBJECTIVES

To use, existing critical care and early pandemic, data to inform care during the pandemic influenza A 2009 (H1N1) pandemic (with a possible use for triage - if the demand for critical care seriously exceeded supply). To monitor the impact of the H1N1 pandemic on critical care services, in real time, with regular feedback to critical care clinicians and other relevant jurisdictions to inform ongoing policy and practice.

DESIGN

Modelling of data and cohort study.

SETTING

Modelling - 148 adult, general critical care units in England, Wales and Northern Ireland in the Intensive Care National Audit & Research Centre Case Mix Programme. Cohort study - 192 acute hospitals in England, Wales, Northern Ireland, Scotland and the Republic of Ireland.

PARTICIPANTS

Modelling - 105,397 admissions to adult, general critical care units. Cohort study - 1728 H1N1 pandemic-related admissions referred and assessed as requiring critical care.

MAIN OUTCOME MEASURES

Modelling - requirement for organ support and acute hospital mortality. Cohort study - survival to the end of critical care.

RESULTS

Modelling - cancelled or postponed, elective or scheduled surgery resulted in savings in calendar days of critical, Level 3 and advanced respiratory care of 17, 11 and 10%, respectively. These savings varied across units. Using routine, physiological variables, the best triage models, for all and for acute respiratory admissions, achieved only satisfactory concordance of 0.79 and 0.75, respectively. Application of the best model on all admissions indicated that approximately 12.5% of calendar days of critical care could be saved. Cohort study - research governance approvals were achieved for 192 acute hospitals, for 91 within 1 day of central research and development approval across the five countries. A total of 1725 cases (562 confirmed) were reported. Confirmed cases were young (mean age of 40 years), had low severity of acute illness on presentation [61% CURB-65 (confusion, urea, respiratory rate, blood pressure, age over 65 years) 0-1], but had long stays in critical care (median 8.5 days) and were likely to be ventilated (77% for median 9 days). Risk factors for acute hospital death were similar to those for general critical care admissions.

CONCLUSIONS

SwiFT was rapidly established. Models based on routine physiology suggested limited value for triage. More data and further modelling are warranted. The magnitude of the pandemic did not approach the worst-case scenario modelling, and UK-confirmed H1N1 cases appeared similar to those reported internationally.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Nasal potential difference to detect Na+ channel dysfunction in acute lung injury

Pulmonary fluid clearance is regulated by the active transport of Na(+) and Cl(-) through respiratory epithelial ion channels. Ion channel dysfunction contributes to the pathogenesis of various pulmonary fluid disorders including high-altitude pulmonary edema (HAPE) and neonatal respiratory distress syndrome (RDS). Nasal potential difference (NPD) measurement allows an in vivo investigation of the functionality of these channels. This technique has been used for the diagnosis of cystic fibrosis, the archetypal respiratory ion channel disorder, for over a quarter of a century. NPD measurements in HAPE and RDS suggest constitutive and acquired dysfunction of respiratory epithelial Na(+) channels. Acute lung injury (ALI) is characterized by pulmonary edema due to alveolar epithelial-interstitial-endothelial injury. NPD measurement may enable identification of critically ill ALI patients with a susceptible phenotype of dysfunctional respiratory Na(+) channels and allow targeted therapy toward Na(+) channel function.

A national clinical scenario-based survey of clinicians' attitudes towards fresh frozen plasma transfusion for critically ill patients

BACKGROUND

It is known that 20-30% of fresh frozen plasma (FFP) is used in intensive care units (ICUs), but little is known about variations in decision making between clinicians in relation to coagulopathy management. Our aim was to describe ICU clinicians' beliefs and practice in relation to FFP treatment of non-bleeding coagulopathic critically ill patients.

METHODS

Two patient-based scenarios were developed and sent to 2700 members of two UK intensive care professional societies. Scenario 1 was a non-bleeding septic patient with coagulopathy; scenario 2 was a non-bleeding critically ill patient with hepatic cirrhosis and coagulopathy. Responses were sought in relation to FFP prophylaxis, and prior to central venous cannulation. A supplementary question asked clinicians' view of prophylaxis in relation to other ICU procedures.

RESULTS

Two-thousand-and-seven-hundred clinicians were surveyed from whom 601 responses were received (22·3% response rate). For scenario 1 52% of respondents stated that they would never routinely administer prophylactic FFP, but this decreased to 9% when central venous cannulation was planned (P < 0·01). There was wide variation in the 'trigger' INR (international normalised ratio) value used prior to central vein cannulation, the most common range being 2·0-2·4. For scenario 2, responses were very similar. More than 80% of clinicians stated that they would routinely treat coagulopathy prior to lumbar puncture, epidural catheterisation, intracranial pressure monitoring and tracheostomy; and 54% prior to chest drain insertion.

CONCLUSION

Our survey demonstrated a wide range of responses consistent with important variations in clinical practice and substantial clinical uncertainty in relation to FFP treatment for non-bleeding ICU patients.

A national survey of the management of delirium in UK intensive care units

BACKGROUND

Delirium is an acute organ dysfunction common amongst patients treated in intensive care units. The associated morbidity and mortality are known to be substantial. Previous surveys have described which screening tools are used to diagnose delirium and which medications are used to treat delirium, but these data are not available for the United Kingdom.

AIM

This survey aimed to describe the UK management of delirium by consultant intensivists. Additionally, knowledge and attitudes towards management of delirium were sought. The results will inform future research in this area.

METHODS

A national postal survey of members of the UK Intensive Care Society was performed. A concise two page questionnaire survey was sent, with a second round of surveys sent to non-respondents after 6 weeks. The questionnaire was in tick-box format.

RESULTS

Six hundred and eighty-one replies were received from 1308 questionnaires sent, giving a response rate of 52%. Twenty-five percent of respondents routinely screen for delirium, but of these only 55% use a screening tool validated for use in intensive care. The majority (80%) of those using a validated instrument used the Confusion Assessment Method for the Intensive Care Unit. Hyperactive delirium is treated pharmacologically by 95%; hypoactive delirium is treated pharmacologically by 25%, with haloperidol the most common agent used in both. Over 80% of respondents agreed that delirium prolongs mechanical ventilation and hospital stay and requires active treatment.

CONCLUSION

This UK survey demonstrates screening for delirium is sporadic. Pharmacological treatment is usually with haloperidol in spite of the limited evidence to support this practice. Hypoactive delirium is infrequently treated pharmacologically.

The impact of a PCR assay for candidemia on antifungal drug prescribing in critical care: an interrupted time series pilot study

SUMMARY OBJECTIVE

To evaluate the feasibility of conducting a definitive study to assess the impact of introducing a rapid PCR-based test for candidemia on antifungal drug prescribing.

METHOD

Prospective, single centre, interrupted time series study consisting of three periods of six months' duration. The assay was available during the second period, during which the PCR assay was available for routine use by physicians Monday-Friday with guaranteed 24-h turnaround time. For each period total antifungal drug use, expressed as treatment-days, was recorded and an adjustment was made to exclude estimated use for proven candidemia. Also, during the intervention period, antifungal prescribing decisions for up to 72 h after each PCR result became available were recorded as either concordant or discordant with that result.

RESULTS

While overall antifungal use remained relatively stable throughout, after adjustment for candidemia, there was a 38% reduction in use following introduction of the PCR test; however, this was nonsignificant at the 95% level. During the intervention period overall concordance between the PCR result and prescribing decisions was 84%.

CONCLUSIONS

The PCR assay for candidemia was requested, prescribing decisions were generally concordant with the results produced and there was an apparent decrease in antifungal prescription, although this was sustained even after withdrawal of the intervention; these findings should be more thoroughly evaluated in a larger trial.

Soluble endostatin is a novel inhibitor of epithelial repair in idiopathic pulmonary fibrosis

BACKGROUND AND AIM

Aberrant angiogenesis and defective epithelial repair are key features of idiopathic pulmonary fibrosis (IPF). Endostatin is an antiangiogenic peptide with known effects on endothelial cells. This study aimed to establish the levels of endostatin in the bronchoalveolar lavage fluid (BALF) in IPF and to investigate its actions on distal lung epithelial cells (DLEC) and primary type II cells.

METHODS

20 patients with IPF and 10 controls underwent BAL. Endostatin was measured by ELISA. BALF cytokines and matrix metalloproteinase (MMP)-3 were measured by Luminex array. Primary DLEC monolayers were wounded and treated with endostatin. Apoptosis and cell viability were assessed.

RESULTS

Endostatin was elevated in the BALF and plasma of patients with IPF compared with normal controls. There was a negative correlation between endostatin, forced vital capacity and gas transfer. Endostatin correlated with a number of proinflammatory cytokines and MMP3. Physiological endostatin doses inhibited DLEC wound repair by 44% in an effect that was partially FasL and caspase dependent. Endostatin increased apoptosis rates by 8% and reduced their viability by 34%. Similar effects of endostatin were seen in primary type II cells in terms of inhibition of wound repair and proliferation.

CONCLUSIONS

Elevated BALF endostatin levels correlated with a number of elevated cytokines, MMP3 and lung function in IPF. Endostatin is a novel inhibitor of DLEC wound repair, inducing apoptosis and reducing cell viability in a FasL and caspase dependent manner. Endostatin may play a role in aberrant epithelial repair in IPF.

MMP expression and abnormal lung permeability are important determinants of outcome in IPF

Matrix metalloproteinases (MMPs) degrade all of the extracellular matrix components of the intersititium and may play a role in abnormal alveolar permeability, which is a feature of idiopathic pulmonary fibrosis (IPF). The aims of the present study were to evaluate MMP protein levels in patients with IPF and determine any relationship to treatment and markers of permeability. In total, 20 patients with IPF and eight normal controls underwent bronchoalveolar lavage. MMP, tissue inhibitor of metalloproteinase, and vascular endothelial growth factor (VEGF) levels were related to clinical outcome and protein permeability index. MMP-3, -7, -8 and -9 were elevated in IPF lavage fluid and levels remained high despite treatment. Levels of MMP-3, -7, -8 and -9, VEGF and protein permeability index were higher in those who died early during follow-up. VEGF, and MMP-8 and -9 levels were higher in those with a rapidly declining lung function over 1 yr. Levels of MMP-3, -7, -8 and -9 correlated with an increased permeability index. Matrix metalloproteinase levels were elevated in idiopathic pulmonary fibrosis patients and were not modulated by current standard treatment. Matrix metalloproteinase production through an interaction with the known vascular permogen, vascular endothelial growth factor, was potentially associated with abnormal capillary permeability and may have potentiated the neo-angiogenesis seen in idiopathic pulmonary fibrosis. The changes were greatest in those who died or progressed during follow-up, suggesting that drugs targeting vascular endothelial growth factor or matrix metalloproteinase activity warrant assessment as novel therapy for idiopathic pulmonary fibrosis.

Predictors of mortality in acute lung injury during the era of lung protective ventilation

BACKGROUND

Lung protective ventilation has been widely adopted for the management of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Consequently, ventilator associated lung injury and mortality have decreased. It is not known if this ventilation strategy changes the prognostic value of previously identified demographic and pulmonary predictors of mortality, such as respiratory compliance and the arterial oxygen tension to inspired oxygen fraction ratio (Pao(2)/Fio(2)).

METHODS

Demographic, clinical, laboratory and pulmonary variables were recorded in 149 patients with ALI/ARDS. Significant predictors of mortality were identified in bivariate analysis and these were entered into multivariate analysis to identify independent predictors of mortality.

RESULTS

Hospital mortality was 41%. In the bivariate analysis, 17 variables were significantly correlated with mortality, including age, APACHE II score and the presence of cirrhosis. Pulmonary parameters associated with death included Pao(2)/Fio(2) and oxygenation index ((mean airway pressurexFio(2)x100)/Pao(2)). In unadjusted analysis, the odds ratio (OR) of death for Pao(2)/Fio(2) was 1.57 (CI 1.12 to 3.04) per standard deviation decrease. However, in adjusted analysis, Pao(2)/Fio(2) was not a statistically significant predictor of death, with an OR of 1.29 (CI 0.82 to 2.02). In contrast, oxygenation index (OI) was a statistically significant predictor of death in both unadjusted analysis (OR 1.89 (CI 1.28 to 2.78)) and in adjusted analysis (OR 1.84 (CI 1.13 to 2.99)).

CONCLUSIONS

In this cohort of patients with ALI/ARDS, OI was an independent predictor of mortality, whereas Pao(2)/Fio(2) was not. OI may be a superior predictor because it integrates both airway pressure and oxygenation into a single variable.

In vitro and in vivo effects of salbutamol on neutrophil function in acute lung injury

BACKGROUND

Intravenous salbutamol (albuterol) reduces lung water in patients with the acute respiratory distress syndrome (ARDS). Experimental data show that it also reduces pulmonary neutrophil accumulation or activation and inflammation in ARDS.

AIM

To investigate the effects of salbutamol on neutrophil function.

METHODS

The in vitro effects of salbutamol on neutrophil function were determined. Blood and bronchoalveolar lavage (BAL) fluid were collected from 35 patients with acute lung injury (ALI)/ARDS, 14 patients at risk from ARDS and 7 ventilated controls at baseline and after 4 days' treatment with placebo or salbutamol (ALI/ARDS group). Alveolar-capillary permeability was measured in vivo by thermodilution (PiCCO). Neutrophil activation, adhesion molecule expression and inflammatory cytokines were measured.

RESULTS

In vitro, physiological concentrations of salbutamol had no effect on neutrophil chemotaxis, viability or apoptosis. Patients with ALI/ARDS showed increased neutrophil activation and adhesion molecule expression compared with at risk-patients and ventilated controls. There were associations between alveolar-capillary permeability and BAL myeloperoxidase (r = 0.4, p = 0.038) and BAL interleukin 8 (r = 0.38, p = 0.033). In patients with ALI/ARDS, salbutamol increased numbers of circulating neutrophils but had no effect on alveolar neutrophils.

CONCLUSION

At the onset of ALI/ARDS, there is increased neutrophil recruitment and activation. Physiological concentrations of salbutamol did not alter neutrophil chemotaxis, viability or apoptosis in vitro. In vivo, salbutamol increased circulating neutrophils, but had no effect on alveolar neutrophils or on neutrophil activation. These data suggest that the beneficial effects of salbutamol in reducing lung water are unrelated to modulation of neutrophil-dependent inflammatory pathways.

Regulation of vascular endothelial growth factor bioactivity in patients with acute lung injury

BACKGROUND

Reduced bioactive vascular endothelial growth factor (VEGF) has been demonstrated in several inflammatory lung conditions including the acute respiratory distress syndrome (ARDS). sVEGFR-1, a soluble form of VEGF-1 receptor, is a potent natural inhibitor of VEGF. We hypothesised that sVEGFR-1 plays an important role in the regulation of the bioactivity of VEGF within the lung in patients with ARDS.

METHODS

Forty one patients with ARDS, 12 at risk of developing ARDS, and 16 normal controls were studied. Bioactive VEGF, total VEGF, and sVEGFR-1 were measured by ELISA in plasma and bronchoalveolar lavage (BAL) fluid. Reverse transcriptase polymerase chain reaction for sVEGFR-1 was performed on BAL cells.

RESULTS

sVEGFR-1 was detectable in the BAL fluid of 48% (20/41) of patients with early ARDS (1.4-54.8 ng/ml epithelial lining fluid (ELF)) compared with 8% (1/12) at risk patients (p = 0.017) and none of the normal controls (p = 0.002). By day 4 sVEGFR-1 was detectable in only 2/18 ARDS patients (p = 0.008). Patients with detectable sVEGFR-1 had lower ELF median (IQR) levels of bioactive VEGF than those without detectable sVEGFR-1 (1415.2 (474.9-3192) pg/ml v 4761 (1349-7596.6) pg/ml, median difference 3346 pg/ml (95% CI 305.1 to 14711.9), p = 0.016), but there was no difference in total VEGF levels. BAL cells expressed mRNA for sVEGFR-1 and produced sVEGFR-1 protein which increased following incubation with tumour necrosis factor alpha.

CONCLUSION

This study shows for the first time the presence of sVEGFR-1 in the BAL fluid of patients with ARDS. This may explain the presence of reduced bioactive VEGF in patients early in the course of ARDS.

Randomised controlled cross-over comparison of continuous positive airway pressure through the Hamilton Galileo ventilator with a Dräger CF 800 device

In this controlled, randomised cross-over trial on 26 intensive care patients, we compared the effects on haemodynamic and respiratory profiles of continuous positive airway pressure delivered through the Hamilton Galileo ventilator or a Drager CF 800 device. We also compared the nursing time saved using the two approaches when weaning patients from mechanical ventilation. We did not find significant differences in haemodynamics, respiratory rate, physiological dead space, oxygen saturation and carbon dioxide production between the continuous positive airway pressure generated by the Galileo and Drager machines. However, there was a 10-fold reduction in nursing time using the Galileo ventilator compared with the Drager generator. We conclude that continuous positive airway pressure delivered through the Galileo ventilator is as efficient as a Drager device but consumes less nursing time.

What is the optimal duration of ventilation in the prone position in acute lung injury and acute respiratory distress syndrome?

OBJECTIVE

To evaluate the effects of prone ventilation on respiratory parameters and extravascular lung water (EVLW) in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in order to characterise the optimal duration of ventilation in the prone position.

DESIGN

Prospective, observational study.

SETTING

Nine-bed general intensive care unit.

PATIENTS

Eleven patients with refractory hypoxaemia due to ALI/ARDS were prospectively investigated during 12 consecutive episodes of prone ventilation.

INTERVENTIONS

Ventilation in the prone position for 18 h.

MEASUREMENTS AND MAIN RESULTS

Measurements were obtained supine and after 1, 2, 6, 12 and 18 h in the prone position and 1 h after returning supine. There was a progressive improvement in PaO(2)/fraction of inspired oxygen (FIO(2)) ratio which reached significance after 12 h [121 (81-151) to 258 (187-329) torr; p<0.05]. EVLW index increased transiently at 1 h [14.2 (7.6-20.8) to 15.1 (9.0-20.2); p=0.05] and thereafter declined progressively and was significantly decreased at 18 h [12.1 (7.2-17.0); p=0.043]. The shunt fraction showed an early fall [0.41 (0.40-0.42) to 0.31 (0.30-0.32) at 1 h; p<0.001] preceding a subsequent progressive fall [0.22 (0.21-0.23) at 18 h; p<0.001].

CONCLUSIONS

Over the 18 h period studied there was progressive improvement in gas exchange, pulmonary shunt and EVLW. Although it is not possible to exclude that improvement over this period was unrelated to prone positioning, these findings suggests that ventilation in the prone position for more prolonged periods may be required for optimal improvement and warrants further study.

Churg-Strauss syndrome associated with leukotriene receptor antagonists

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