Recovery from lung injury in survivors of acute respiratory distress syndrome: difference between pulmonary and extrapulmonary subtypes

Whole pulmonary assessment 1 year after paediatric acute respiratory distress syndrome: prospective multicentre study

Background

Long-term pulmonary sequelae, including 1-year thoracic computed tomography (CT) sequelae of paediatric acute respiratory distress syndrome (ARDS) remain unknown. The purpose of the study was to determine pulmonary abnormalities in child survivors of pulmonary (p-ARDS) and extra-pulmonary ARDS (ep-ARDS) 1 year after paediatric intensive care unit discharge (PICUD).

Methods

Prospective multicentre study in four paediatric academic centres between 2005 and 2014. Patients with ARDS were assessed 1 year after PICUD with respiratory symptom questionnaire, thoracic CT and pulmonary function tests (PFT).

Results

39 patients (31 p-ARDS) aged 1.1–16.2 years were assessed. Respiratory symptoms at rest or exercise and/or respiratory maintenance treatment were reported in 23 (74%) of children with p-ARDS but in 1 (13%) of those with ep-ARDS. Thoracic CT abnormalities were observed in 18 (60%) of children with p-ARDS and 4 (50%) of those with ep-ARDS. Diffuse and more important CT abnormalities, such as ground glass opacities or mosaic perfusion patterns, were observed in 5 (13%) of children, all with p-ARDS. PFT abnormalities were observed in 30 (86%) of patients: lung hyperinflation and/or obstructive pattern in 12 (34%) children, restrictive abnormalities in 6 (50%), mild decrease in diffusing capacity in 2 (38%) and 6-min walking distance decrease in 11 (73%). Important PFT abnormalities were observed in 7 (20%) children, all with p-ARDS. Increasing driving pressure (max plateau pressure—max positive end-expiratory pressure) was correlated with increasing CT-scan abnormalities and increasing functional residual capacity (more hyperinflation) (p < 0.005).

Conclusions

Children surviving ARDS requiring mechanical ventilation present frequent respiratory symptoms, significant CT-scan and PFT abnormalities 1 year after PICUD. This highlights the need for a systematic pulmonary assessment of these children.

Trial registration The study was registered on Clinical Trials.gov PRS (ID NCT01435889)

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01050-4.

Chronic critical illness and post-intensive care syndrome: from pathophysiology to clinical challenges

Background

Post‐intensive care syndrome (PICS) encompasses physical, cognition, and mental impairments persisting after intensive care unit (ICU) discharge. Ultimately it significantly impacts the long‐term prognosis, both in functional outcomes and survival. Thus, survivors often develop permanent disabilities, consume a lot of healthcare resources, and may experience prolonged suffering. This review aims to present the multiple facets of the PICS, decipher its underlying mechanisms, and highlight future research directions.

Main text

This review abridges the translational data underlying the multiple facets of chronic critical illness (CCI) and PICS. We focus first on ICU-acquired weakness, a syndrome characterized by impaired contractility, muscle wasting, and persisting muscle atrophy during the recovery phase, which involves anabolic resistance, impaired capacity of regeneration, mitochondrial dysfunction, and abnormalities in calcium homeostasis. Second, we discuss the clinical relevance of post-ICU cognitive impairment and neuropsychological disability, its association with delirium during the ICU stay, and the putative role of low-grade long-lasting inflammation. Third, we describe the profound and persistent qualitative and quantitative alteration of the innate and adaptive response. Fourth, we discuss the biological mechanisms of the progression from acute to chronic kidney injury, opening the field for renoprotective strategies. Fifth, we report long-lasting pulmonary consequences of ARDS and prolonged mechanical ventilation. Finally, we discuss several specificities in children, including the influence of the child’s pre-ICU condition, development, and maturation.

Conclusions

Recent understandings of the biological substratum of the PICS’ distinct features highlight the need to rethink our patient trajectories in the long term. A better knowledge of this syndrome and precipitating factors is necessary to develop protocols and strategies to alleviate the CCI and PICS and ultimately improve patient recovery.

Quality of life and functional status of patients treated with venovenous extracorporeal membrane oxygenation at 6 months

PURPOSE

Quality of life (QoL) outcomes of patients treated with extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) have been conflicting. This study reports on QoL outcomes for a broad group of ARDS patients managed with up-to-date treatment modalities.

METHODS

We prospectively recruited patients at a quaternary hospital in the United Kingdom from 2013 to 2015 who were treated with ECMO for ARDS. We evaluated their pulmonary function and QoL at 6-months after admission using three QoL instruments: EuroQoL 5D (EQ-5), HADS, and PTSS-14.

RESULTS

Forty-three patients included in the analysis had near-normal pulmonary function at 6 months. HADS showed moderate-to-severe anxiety and depression in 32% and 11% of patients, respectively. PTSS-14 showed 29% had signs of post-traumatic stress disorder. EQ-5D showed that 67% of patients had difficulty returning to usual activities, 74% suffered some pain, none reported severe problems and 77% were able to return to work. No clinical or demographic variables were associated with poor 6-month QoL.

CONCLUSIONS

Patients with ARDS treated with ECMO generally had good QoL outcomes, similar to outcomes reported for patients managed without ECMO. With respect to QoL, VV-EMCO represents a valid treatment modality for patients with refractory ARDS.

Association between ARDS Etiology and Risk of Noninvasive Ventilation Failure

RATIONALE

The etiology of acute respiratory distress syndrome (ARDS) may play an important role in the failure of noninvasive ventilation (NIV).

OBJECTIVES

To explore the association between ARDS etiology and risk of noninvasive ventilation failure.

METHODS

A multicenter prospective observational study was performed in 17 ICUs in China from September 2017 to December 2019. Patients with ARDS who used NIV as a first-line therapy were enrolled. The etiology of ARDS was recorded at study entry.

RESULTS

A total of 306 patients were enrolled. Of the patients, 146 were classified as having pulmonary ARDS (ARDSp) and 160 were classified as having extrapulmonary ARDS (ARDSexp). From initiation to 24 h of NIV, the respiratory rate, heart rate, PaO2/FiO2, and PaCO2 improved slower in patients with ARDSp than those with ARDSexp. Patients with ARDSp experienced more NIV failure (55% vs. 28%; p < 0.01) and higher 28-day mortality (47% vs. 14%; p < 0.01). The adjusted odds ratio of NIV failure and 28-day mortality were 5.47 (95%CI: 3.04-9.86) and 10.13 (95%CI: 5.01-20.46), respectively. In addition, we combined the presence of ARDSp, presence of septic shock, age, non-pulmonary SOFA score, respiratory rate at 1-2 h of NIV, and PaO2/FiO2 at 1-2 h of NIV to develop a risk score of NIV failure. With the increase of the risk score, the rate of NIV failure increased. Using 5.5 as cutoff value to predict NIV failure, the sensitivity and specificity was good both in training and validation cohorts.

CONCLUSIONS

Among patients with ARDS who used NIV as a first-line therapy, ARDSp was associated with slower improvement, more NIV failure, and higher 28-day mortality than ARDSexp. The risk score combined presence of ARDSp, presence of septic shock, age, non-pulmonary SOFA score, respiratory rate at 1-2 h of NIV, and PaO2/FiO2 at 1-2 h of NIV has high accuracy to predict NIV failure among ARDS population.

Ultraprotective ventilation allowed by extracorporeal CO2 removal improves the right ventricular function in acute respiratory distress syndrome patients: a quasi-experimental pilot study

Background

Right ventricular (RV) failure is a common complication in moderate-to-severe acute respiratory distress syndrome (ARDS). RV failure is exacerbated by hypercapnic acidosis and overdistension induced by mechanical ventilation. Veno-venous extracorporeal CO₂ removal (ECCO₂R) might allow ultraprotective ventilation with lower tidal volume (V_T) and plateau pressure (P_plat). This study investigated whether ECCO₂R therapy could affect RV function.

Methods

This was a quasi-experimental prospective observational pilot study performed in a French medical ICU. Patients with moderate-to-severe ARDS with PaO₂/FiO₂ ratio between 80 and 150 mmHg were enrolled. An ultraprotective ventilation strategy was used with V_T at 4 mL/kg of predicted body weight during the 24 h following the start of a low-flow ECCO₂R device. RV function was assessed by transthoracic echocardiography (TTE) during the study protocol.

Results

The efficacy of ECCO₂R facilitated an ultraprotective strategy in all 18 patients included. We observed a significant improvement in RV systolic function parameters. Tricuspid annular plane systolic excursion (TAPSE) increased significantly under ultraprotective ventilation compared to baseline (from 22.8 to 25.4 mm; p < 0.05). Systolic excursion velocity (S’ wave) also increased after the 1-day protocol (from 13.8 m/s to 15.1 m/s; p < 0.05). A significant improvement in the aortic velocity time integral (VTIAo) under ultraprotective ventilation settings was observed (p = 0.05). There were no significant differences in the values of systolic pulmonary arterial pressure (sPAP) and RV preload.

Conclusion

Low-flow ECCO₂R facilitates an ultraprotective ventilation strategy thatwould improve RV function in moderate-to-severe ARDS patients. Improvement in RV contractility appears to be mainly due to a decrease in intrathoracic pressure allowed by ultraprotective ventilation, rather than a reduction of PaCO₂.

The long-lasting effects of the acute respiratory distress syndrome

Introduction: Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury common in critically ill patients and characterized by significant morbidity and mortality. It frequently manifests long-lasting effects beyond hospitalization, from cognitive impairment to physical weakness.Areas covered: Several complications of ARDS have been identified in patients after hospital discharge. The authors conducted literature searches to identify observational studies, randomized clinical trials, systematic reviews, and guidelines. A summary of is presented here to outline the sequelae of ARDS and their risk factors with a focus on the limited but growing research into possible therapies. Long term sequelae of ARDS commonly identified in the literature include long-term cognitive impairment, psychological morbidities, neuromuscular weakness, pulmonary dysfunction, and ongoing healthcare utilization with reduced quality of life.Expert opinion: Given the public health significance of long-term complications following ARDS, the development of new therapies for prevention and treatment is of vital importance. Furthering knowledge of the pathophysiology of these impairments will provide a framework to develop new therapeutic targets to fuel future clinical trials in this area of critical care medicine.

Complications and Outcomes of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is a disease associated with both short- and long-term complications. Acute complications include refractory respiratory failure requiring prolonged dependence on mechanical ventilation and the subsequent need for tracheostomy and gastrostomy tubes, protracted immobilization, and lengthy stays in the intensive care unit resulting in delirium, critical illness myopathy, and polyneuropathy, as well as secondary nosocomial infections. Chronic adverse outcomes of ARDS include irreversible changes such as fibrosis, tracheal stenosis from prolonged tracheostomy tube placement, pulmonary function decline, cognitive impairment and memory loss, posttraumatic stress disorder, depression, anxiety, muscle weakness, ambulatory dysfunction, and an overall poor quality of life. The degree of disability in ARDS survivors is heterogeneous and can be evident even years after hospitalization. Although survival rates have improved over the past 4 decades, mortality remains significant with rates reported as high as 40%. Despite advancements in management, the causes of death in ARDS have remained relatively unchanged since the 1980s with sepsis/septic shock and multiorgan failure at the top of the list.

ERS statement on chest imaging in acute respiratory failure

Chest imaging in patients with acute respiratory failure plays an important role in diagnosing, monitoring and assessing the underlying disease. The available modalities range from plain chest X-ray to computed tomography, lung ultrasound, electrical impedance tomography and positron emission tomography. Surprisingly, there are presently no clear-cut recommendations for critical care physicians regarding indications for and limitations of these different techniques.The purpose of the present European Respiratory Society (ERS) statement is to provide physicians with a comprehensive clinical review of chest imaging techniques for the assessment of patients with acute respiratory failure, based on the scientific evidence as identified by systematic searches. For each of these imaging techniques, the panel evaluated the following items: possible indications, technical aspects, qualitative and quantitative analysis of lung morphology and the potential interplay with mechanical ventilation. A systematic search of the literature was performed from inception to September 2018. A first search provided 1833 references. After evaluating the full text and discussion among the committee, 135 references were used to prepare the current statement.These chest imaging techniques allow a better assessment and understanding of the pathogenesis and pathophysiology of patients with acute respiratory failure, but have different indications and can provide additional information to each other.

Determinants of Quality of Life and Return to Work Following Acute Respiratory Distress Syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) in adults is a consequence of lung damage caused by either pulmonary or extrapulmonary disease. Survivors often suffer from an impaired health-related quality of life (HRQoL), mental and physical impairments, and persistent inability to work.

METHODS

In this systematic review of the literature, we consider the determinants of HRQoL and return to work (RtW). 24 observational studies showing a statistical association between one or more determinants and HRQoL or RtW were included. Because of the heterogeneity of these studies, no statistical aggregation of the individual effect estimates was carried out; instead, the results are summarized descriptively.

RESULTS

Psychopathological manifestations, in particular, are associated with impaired quality of life. In contrast, many care- and disease-related determinants had only small, non-significant effects on HRQoL and RtW. The onesecond capacity was found in all studies to be positively associated with the HRQoL. ARDS induced by sepsis seems to be a risk factor for a lower HRQoL in comparison to ARDS of other causes. A synthesis of the evidence is impeded both by the high level of heterogeneity of studies and by the high risk of selection bias in all studies.

CONCLUSION

The identification of determinants of impaired quality of life after ARDS is essential for the assessment of clinically relevant interventions. In multiple studies, major significant effects were only observed when determinants the content of which was closely related to the scales of the HRQoL instruments were measured at the same time as the HRQoL.

Subtypes of pediatric acute respiratory distress syndrome have different predictors of mortality

PURPOSE

Acute respiratory distress syndrome (ARDS) is heterogeneous in etiology, which may affect outcomes. Stratification into biologically-defined subtypes may reduce heterogeneity. However, it is unknown whether pediatric ARDS has clinically relevant subtypes. We aimed to determine whether clinical characteristics and predictors of mortality differed between direct and indirect ARDS, and separately between infectious and non-infectious ARDS.

METHODS

This was a single center, prospective cohort study of 544 children with ARDS (Berlin) between July 2011 and June 2017, stratified into direct versus indirect ARDS, and separately into infectious versus non-infectious ARDS. Multiple logistic regression was used to test for predictors of mortality in the entire cohort, and separately within subtypes. Effect modification by subtype was assessed using interaction tests.

RESULTS

Direct ARDS had lower severity of illness (p < 0.001) but worse oxygenation (p < 0.001), relative to indirect. Predictors of mortality were similar for direct and indirect ARDS. When comparing infectious and non-infectious ARDS, infectious ARDS had lower severity of illness (p < 0.001), worse oxygenation (p = 0.014), and lower mortality (p = 0.013). In multivariable analysis, immunocompromised status demonstrated effect modification between infectious and non-infectious ARDS (p = 0.005 for interaction), with no association with mortality in non-infectious ARDS.

CONCLUSIONS

In children, direct and indirect ARDS have distinct clinical characteristics, but similar outcomes and similar predictors of mortality. In contrast, infectious and non-infectious ARDS demonstrate heterogeneity of clinical characteristics, mortality, and predictors of mortality, with traditional predictors of ARDS mortality only applicable to infectious ARDS.

Plasma microRNAs levels are different between pulmonary and extrapulmonary ARDS patients: a clinical observational study

BACKGROUND

Mesenchymal stem cells (MSC) obviously alleviate the damage of the structure and function of pulmonary vascular endothelial cells (VEC). The therapeutic effects of MSC are significantly different between pulmonary ARDS (ARDSp) and extrapulmonary ARDS (ARDSexp). MicroRNAs (miRNAs), as important media of MSC regulating VEC, are not studied between ARDSp and ARDSexp. We aimed to explore the plasma levels difference of miRNAs that regulate VEC function and are associated with MSC (MSC-VEC-miRNAs) between ARDSp and ARDSexp patients.

METHODS

MSC-VEC-miRNAs were obtained through reviewing relevant literatures screened in PubMed database. We enrolled 57 ARDS patients within 24 h of admission to the ICU and then collected blood samples, extracted plasma supernatant. Patients' clinical data were collected. Then, plasma expression of MSC-VEC-miRNAs was measured by real-time fluorescence quantitative PCR. Simultaneously, plasma endothelial injury markers VCAM-1, vWF and inflammatory factors TNF-α, IL-10 were detected by ELISA method.

RESULTS

Fourteen miRNAs were picked out after screening. A total of 57 ARDS patients were included in this study, among which 43 cases pertained to ARDSp group and 14 cases pertained to ARDSexp group. Plasma miR-221 and miR-27b levels in ARDSexp group exhibited significantly lower than that in ARDSp group (miR-221, 0.22 [0.12-0.49] vs. 0.57 [0.22-1.57], P = 0.008, miR-27b, 0.34 [0.10-0.46] vs. 0.60 [0.20-1.46], P = 0.025). Plasma vWF concentration in ARDSexp group exhibited significantly lower than that in ARDSp group (0.77 [0.29-1.54] vs. 1.80 [0.95-3.51], P = 0.048). Significant positive correlation was found between miR-221 and vWF in plasma levels (r = 0.688, P = 0.022). Plasma miR-26a and miR-27a levels in non-survival group exhibited significantly lower than that in survival group (miR-26a, 0.17 [0.08-0.20] vs. 0.69 [0.24-2.33] P = 0.018, miR-27a, 0.23 [0.16-0.58] vs. 1.45 [0.38-3.63], P = 0.021) in ARDSp patients.

CONCLUSION

Plasma miR-221, miR-27b and vWF levels in ARDSexp group are significantly lower than that in ARDSp group. Plasma miR-26a and miR-27a levels in non-survival group are significantly lower than that in survival group in ARDSp patients.

Long-Term Quality of Life After Extracorporeal Membrane Oxygenation in ARDS Survivors: Systematic Review and Meta-Analysis

PURPOSE

Extracorporeal membrane oxygenation (ECMO) is an increasingly prevalent treatment for acute respiratory failure (ARF). To evaluate the impact of ECMO support on long-term outcomes for critically ill adults with ARF.

METHODS

We searched electronic databases 1948 through to November 30 2016; selected controlled trials or observational studies of critically ill adults with acute respiratory distress syndrome, examining long-term morbidity specifically health-related quality of life (HRQL); 2 authors independently selected studies, extracted data, and assessed methodological quality.

ANALYSIS

Of the 633 citations, 1 randomized controlled trial and 5 observational studies met the selection criteria. Overall quality of observational studies was moderate to high (mean score on Newcastle-Ottawa scale, 7.2/9; range, 6-8). In 3 studies (n = 245), greater decrements in HRQL were seen for survivors of ECMO when compared to survivors of conventional mechanical ventilation (CMV) as measured by the Short Form 36 (SF-36) scores ([ECMO-CMV]: 5.40 [95% confidence interval, CI, 4.11 to 6.68]). As compared to CMV survivors, those who received ECMO experienced significantly less psychological morbidity (2 studies; n = 217 [ECMO-CMV]: mean weighted difference [MWD], -1.31 [95% CI, -1.98 to -0.64] for depression and MWD, -1.60 [95% CI, -1.80 to -1.39] for anxiety).

CONCLUSIONS

Further studies are required to confirm findings and determine prognostic factors associated with more favorable outcomes in survivors of ECMO.

Clinical Predictors of Hospital Mortality Differ Between Direct and Indirect ARDS

BACKGROUND

Direct (pulmonary) and indirect (extrapulmonary) ARDS are distinct syndromes with important pathophysiologic differences. The goal of this study was to determine whether clinical characteristics and predictors of mortality differ between direct or indirect ARDS.

METHODS

This retrospective observational cohort study included 417 patients with ARDS. Each patient was classified as having direct (pneumonia or aspiration, n = 250) or indirect (nonpulmonary sepsis or pancreatitis, n = 167) ARDS.

RESULTS

Patients with direct ARDS had higher lung injury scores (3.0 vs 2.8; P < .001), lower Simplified Acute Physiology Score II scores (51 vs 62; P < .001), lower Acute Physiology and Chronic Health Evaluation II scores (27 vs 30; P < .001), and fewer nonpulmonary organ failures (1 vs 2; P < .001) compared with patients with indirect ARDS. Hospital mortality was similar (28% vs 31%). In patients with direct ARDS, age (OR, 1.29 per 10 years; P = .01; test for interaction, P = .03), lung injury scores (OR, 2.29 per point; P = .001; test for interaction, P = .058), and number of nonpulmonary organ failures (OR, 1.67; P = .01) were independent risk factors for increased hospital mortality. Preexisting diabetes mellitus was an independent risk factor for reduced hospital mortality (OR, 0.47; P = .04; test for interaction, P = .02). In indirect ARDS, only the number of organ failures was an independent predictor of mortality (OR, 2.08; P < .001).

CONCLUSIONS

Despite lower severity of illness and fewer organ failures, patients with direct ARDS had mortality rates similar to patients with indirect ARDS. Factors previously associated with mortality during ARDS were only associated with mortality in direct ARDS. These findings suggest that direct and indirect ARDS have distinct features that may differentially affect risk prediction and clinical outcomes.

Long-term outcomes in survivors of acute respiratory distress syndrome ventilated in supine or prone position

PURPOSE

The aim of this study is to examine long-term pulmonary function and quality of life in survivors of acute respiratory distress syndrome (ARDS) previously enrolled in a randomized multicenter trial testing prone compared with supine positioning (PSII study) at five Italian centers.

DESIGN

Observational prospective study.

SUBJECTS AND MEASUREMENTS

Pulmonary function [spirometric test, gas exchange, carbon monoxide diffusion capacity (DLCO)], high-resolution computed tomography (CT) scan, and health-related quality of life [Short Form-36 (SF-36) and St. George's Respiratory Questionnaire] were evaluated at 12 months.

RESULTS

Twenty-six patients (13 in each group, mean age 54.1 ± 2.8 years, body mass index 24.5 ± 1.4 kg/m(2), PaO(2)/FiO(2) 117 ± 49 mmHg) were evaluated. There were no significant differences in demographic data, illness severity, or outcome between the prone and supine groups. The overall survival rate was 40%. Pulmonary function was in the normal range without any differences between the two groups. Quantitative lung CT scan analysis showed similar amounts for not aerated (8.1 ± 3.2% versus 7.3 ± 3.4%), poorly aerated (15.3 ± 3.6% versus 17.1 ± 4.9%), and well-aerated (64.0% ± 8.4 versus 70.2 ± 8.4%) lung regions, while overaerated lung region was slightly higher in the prone compared with the supine group (12.5 ± 6.5% versus 5.3 ± 5.5%). Health-related quality of life was similar to in healthy population. However, these patients showed reduction in daily activity specifically due to pulmonary disease as measured by the St. George's Respiratory Questionnaire.

CONCLUSIONS

No differences in pulmonary function or quality of life were observed in this small group of ARDS survivor patients treated in prone versus supine position.

Lung function and quality of life in survivors of the acute respiratory distress syndrome (ARDS)

Recent studies have begun to describe the long-term outcomes of acute respiratory distress syndrome (ARDS) survivors. These patients experience a number of physical, mental and psychological morbidities that significantly impair their health-related quality of life (HRQL). The trajectory of pulmonary recovery in survivors of ARDS, as it relates to lung function, structure and health-related quality of life (HRQL), is predictable and often persists years after hospital discharge. True pulmonary parenchymal morbidity is uncommon and when present, persistent restrictive disease is likely related to diaphragmatic weakness with a mild reduction in diffusion capacity (DLCO). Future research should focus on identifying patients at risk for long-term functional limitations and the design of rehabilitation interventions tailored to individual patient needs.

Quality of life, pulmonary function, and tomographic scan abnormalities after ARDS

BACKGROUND

ARDS can produce a loss of lung function with persistent sequelae. This study aimed to evaluate health-related quality of life (HRQL) in survivors of ARDS compared with a healthy reference population and to determine the middle/long-term radiographic abnormalities and functional status, as well as their relation to observed HRQL, in these patients.

METHODS

This was a prospective study carried out in three ICUs. HRQL in patients was determined with the Nottingham Health Profile immediately after ARDS diagnosis and 6 months after diagnosis. Patients underwent complete respiratory function testing, chest CT scan study, and the 6-min walk test.

RESULTS

Follow-up was conducted in 38 patients with ARDS. Survivors of ARDS presented a poorer overall HRQL vs the general population, mainly because of lower scores in the dimensions related to mobility, energy, and social isolation. Limitations in daily life activities were documented in 40%. Respiratory function was altered in 67%, with a restrictive respiratory pattern in 58%. Radiologic study disclosed alterations in 76% (mainly reticular pattern). Patients were able to cover only 366 m (318-411 m) in the 6-min walk test and had a minimum pulse oximetry of 93% (90%-94%). A significant correlation was documented between the overall quality of life at first and at 6 months (r = 0.68, P < .01).

CONCLUSIONS

Survivors of ARDS after 6 months had a poorer HRQL than the healthy population and showed mild radiographic and functional involvement. Early HRQL study in these patients enabled early detection of those who would present more long-term HRQL morbidity.

Timing of acute respiratory distress syndrome onset is related to patient outcome

BACKGROUND/PURPOSE

Acute respiratory distress syndrome (ARDS) is a major cause of mortality and morbidity in adult intensive care units. The relationship between the timing of ARDS onset and outcome is not well known. The objective of this study was to investigate the outcome of patients with late-onset ARDS during hospitalization.

METHODS

We prospectively enrolled patients who were intubated and fulfilled ARDS criteria in medical and surgical intensive care units in a tertiary referral medical center from December 1, 2004 to May 31, 2006. Those who developed ARDS more than 48 hours after hospital admission were categorized as late-onset ARDS; otherwise, they were defined as early-onset ARDS. We assessed the risk factors for hospital mortality using multivariate analysis and 90-day survival using Kaplan-Meier analysis between early- and late-onset ARDS, and between direct and indirect ARDS.

RESULTS

A total of 172 patients were included in the study. Overall mortality rate was 70%. Late-onset ARDS [odds ratio (OR): 3.06; 95% confidence interval (CI): 1.41 to 6.63; p = 0.005] and initial shock (OR: 8.20; 95% CI: 3.39-19.79; p < 0.001) were the independent risk factors for hospital mortality. Patients with late-onset ARDS had higher hospital mortality rate (83% vs. 60%; p = 0.002), longer duration of mechanical ventilation (27.0 +/- 23.4 vs. 14.6 +/- 11.5 days; p < 0.001) and length of intensive care unit stay (25.5 +/- 20.6 vs. 15.6 +/- 13.6 days; p < 0.001) than patients with early-onset ARDS. The 90-day survival showed that both early-onset ARDS and direct ARDS were associated with better survival.

CONCLUSION

Patients with late-onset ARDS are associated with poor prognosis and should be managed as high-risk patients.

Quality of life, emotional abnormalities, and cognitive dysfunction in survivors of acute lung injury/acute respiratory distress syndrome

This article provides a brief discussion of the recent literature linking quality-of-life impairment to physical dysfunction after acute lung injury/acute respiratory distress syndrome. Its main focus is a review of the current knowledge concerning cognitive and emotional outcomes after lung injury and their impact on long-term quality of life.

Etiology and outcomes of pulmonary and extrapulmonary acute lung injury/ARDS in a respiratory ICU in North India

OBJECTIVE

Outcomes in patients with ARDS/acute lung injury (ALI) may be dependent on the underlying cause. We describe the case mix, clinical behavior, and outcomes of patients with ALI/ARDS resulting from pulmonary causes (ALI/ARDSp) and extrapulmonary causes (ALI/ARDSexp).

DESIGN

Retrospective study conducted between January 2001 and June 2005.

SETTING

Respiratory ICU (RICU) of a tertiary care hospital in northern India.

PATIENTS

All patients fulfilling the criteria for ALI/ARDS and requiring mechanical ventilation for > 24 h.

MEASUREMENTS AND RESULTS

Of the 180 patients (ARDS, 140 patients; ALI, 40 patients), 123 patients had ALI/ARDSp, whereas 57 patients had ALI/ARDSexp. The most common cause of ALI/ARDSp was infective pneumonia, whereas the most common cause of ALI/ARDSexp was sepsis. At ICU admission, although patients with ALI/ARDSexp were sicker than those with ALI/ARDSp, there was no difference between the two groups of patients in the development of new organ dysfunction/failure (Delta sequential organ failure assessment [SOFA] scores) or the time to develop the first organ dysfunction/failure (assessed by SOFA scores). The median length of RICU stay was similar in the two groups (5 days [interquartile range (IQR), 6 days] vs 5 days [IQR, 9.5 days], respectively, in patients with ALI/ARDSp and ALI/ARDSexp; p = 0.4). The hospital mortality rate was 47.8% and was not significantly different between the two groups (ALI/ARDSp group, 43.1%; ALI/ARDSexp group, 57.9%; p = 0.06). Multivariate analysis showed the following risk factors for death in the ICU: female gender (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.25 to 0.94); SOFA scores (OR, 1.18; 95% CI, 1.07 to 1.3); and DeltaSOFA scores (OR, 1.24; 95% CI, 1.09 to 1.41). There was no significant effect of the category of ARDS on outcome (OR, 1.6; 95% CI, 0.8 to 3.2).

CONCLUSIONS

Although patients with ALI/ARDSexp are sicker on ICU admission, the underlying cause of ARDS does not affect the length of ICU stay or hospital survival time.

Quality of life after acute respiratory distress syndrome: a meta-analysis

OBJECTIVE

To summarize long-term quality of life (QOL) and the degree of variation in QOL estimates across studies of acute respiratory distress (ARDS) survivors.

DESIGN

A systematic review of studies evaluating QOL in ARDS survivors was conducted. Medline, EMBASE, CINAHL, pre-CINAHL, and the Cochrane Library were searched, and reference lists from relevant articles were evaluated. Two authors independently selected studies reporting QOL in adult survivors of ARDS or acute lung injury at least 30 days after intensive care unit discharge and extracted data on study design, patient characteristics, methods, and results.

MEASUREMENTS AND RESULTS

Thirteen independent observational studies (557 patients) met inclusion criteria. Eight of these studies used eight different QOL instruments, allowing only qualitative synthesis of results. The five remaining studies (330 patients) measured QOL using the Medical Outcomes Study 36-Item Short Form survey (SF-36). Mean QOL scores were similar across these studies, falling within a range of 20 points for all domains. Pooled domain-specific QOL scores in ARDS survivors 6 months or later after discharge ranged from 45 (role physical) to 66 (social functioning), or 15-26 points lower than population norms, in all domains except mental health (11 points) and role physical (39 points). Corresponding confidence intervals were no wider than +/-9 points. Six studies all found stable or improved QOL over time, but only one found significant improvement beyond 6 months after discharge.

CONCLUSIONS

ARDS survivors in different clinical settings experience similar decrements in QOL. The precise magnitude of these decrements helps clarify the long-term prognosis for ARDS survivors.

Pulmonary and extrapulmonary acute lung injury: inflammatory and ultrastructural analyses

To test whether pulmonary and extrapulmonary acute lung injury (ALI) of identical mechanical compromise would express diverse morphological patterns and immunological pathways. For this purpose, a model of pulmonary (p) and extrapulmonary (exp) ALI with similar functional changes was developed and pulmonary morphology (light and electron microscopy), cytokines levels, and neutrophilic infiltration in the bronchoalveolar lavage fluid (BALF), elastic and collagen fiber content in the alveolar septa, and neutrophil apoptosis in the lung parenchyma were analyzed. BALB/c mice were divided into four groups. In control groups, saline was intratracheally (it, 0.05 ml) instilled and intraperitoneally (ip, 0.5 ml) injected, respectively. In the ALIp and ALIexp groups, mice received E. coli lipopolysaccharide (10 microg it and 125 microg ip, respectively). The changes in lung resistive and viscoelastic pressures and in static elastance, alveolar collapse, and cell content in lung tissue were similar in the ALIp and ALIexp groups. The ALIp group presented a threefold increase in KC (murine function homolog to IL-8) and IL-10 levels in the BALF in relation to ALIexp, whereas IL-6 level showed a twofold increase in ALIp. Neutrophils in the BALF were more frequent in ALIp than in ALIexp. ALIp showed more extensive injury of alveolar epithelium, intact capillary endothelium, and apoptotic neutrophils, whereas the ALIexp group presented interstitial edema and intact type I and II cells and endothelial layer. In conclusion, given the same pulmonary mechanical dysfunction independently of the etiology of ALI, insult in pulmonary epithelium yielded more pronounced inflammatory responses, which induce ultrastructural morphological changes.