Outcomes of acute respiratory distress syndrome (ARDS) in elderly patients

Etiology and Outcomes of ARDS in the Elderly Population in an Intensive Care Unit in North India

BACKGROUND

Whether age would impact the outcomes in subjects with acute respiratory distress syndrome (ARDS) remains unclear. Herein, we study the effect of age as a predictor of mortality in ARDS.

MATERIALS AND METHODS

We categorized consecutive subjects with ARDS as either ARDSelderly (age >65 years) or ARDSnonelderly (age ≤65 years) admitted to the respiratory intensive care unit (ICU) of a tertiary care hospital in North India between January 2007 and December 2019. We compared the baseline clinical and demographic characteristics, lung mechanics, and mortality between the two groups. We also analyzed the factors predicting ICU survival using multivariate logistic regression analysis.

RESULTS

We included 625 patients (ARDSelderly, 140 [22.4%] and ARDSnonelderly, 485 [77.6%]) with a mean (standard deviation) age (56.3% males) of 40.6 (17.8) years. The ARDSelderly were more likely (p = 0.0001) to have the presence of any comorbid illness compared to ARDSnonelderly. The elderly subjects had significantly higher pulmonary ARDS than the younger group. The severity of ARDS was however, similarly distributed between the two study arms. There were 224 (35.8%) deaths, and the mortality was significantly higher (p = 0.012) in the ARDSelderly than the to ARDSnonelderly (ARDSelderly vs ARDSnonelderly, 45 vs 33.2%). On multivariate logistic regression analysis, the baseline sequential organ failure assessment scores, presence of pulmonary ARDS, and the development of new organ dysfunction were the independent predictors of mortality.

CONCLUSION

The outcomes in subjects with ARDS are dependent on the severity of illness at admission and the etiology of ARDS rather than the age alone.

HOW TO CITE THIS ARTICLE

Sehgal IS, Agarwal R, Dhooria S, Prasad KT, Muthu V, Aggarwal AN. Etiology and Outcomes of ARDS in the Elderly Population in an Intensive Care Unit in North India. Indian J Crit Care Med 2021;25(6):648-654.

Human Umbilical Cord-Derived Mesenchymal Stem Cells for Acute Respiratory Distress Syndrome

OBJECTIVES

To investigate the safety, feasibility, and possible adverse events of single-dose human umbilical cord-derived mesenchymal stem cells in patients with moderate-to-severe acute respiratory distress syndrome.

DESIGN

Prospective phase I clinical trial.

SETTING

Medical center in Kaohsiung, Taiwan.

PATIENTS

Moderate-to-severe acute respiratory distress syndrome with a PaO2/FIO2 ratio less than 200.

INTERVENTIONS

Scaling for doses was required by Taiwan Food and Drug Administration as follows: the first three patients received low-dose human umbilical cord-derived mesenchymal stem cells (1.0 × 10 cells/kg), the next three patients with intermediate dose (5.0 × 10 cells/kg), and the final three patients with high dose (1.0 × 10 cells/kg) between December 2017 and August 2019.

MEASUREMENTS AND MAIN RESULTS

Nine consecutive patients were enrolled into the study. In-hospital mortality was 33.3% (3/9), including two with recurrent septic shock and one with ventilator-induced severe pneumomediastinum and subcutaneous emphysema. No serious prespecified cell infusion-associated or treatment-related adverse events was identified in any patient. Serial flow-cytometric analyses of circulating inflammatory biomarkers (CD14CD33/CD11b+CD16+/CD16+MPO+/CD11b+MPO+/CD14CD33+) and mesenchymal stem cell markers (CD26+CD45-/CD29+CD45-/CD34+CD45-/CD44+CD45-/CD73+CD45-/CD90+CD45-/CD105+CD45-/CD26+CD45-) were notably progressively reduced (p for trend < 0.001), whereas the immune cell markers (Helper-T-cell/Cytotoxity-T-cell/Regulatory-T-cell) were notably increased (p for trend < 0.001) after cell infusion.

CONCLUSIONS

The result of this phase I clinical trial showed that a single-dose IV infusion of human umbilical cord-derived mesenchymal stem cells was safe with favorable outcome in nine acute respiratory distress syndrome patients.

Characteristics, management, and prognosis of elderly patients with COVID-19 admitted in the ICU during the first wave: insights from the COVID-ICU study : Prognosis of COVID-19 elderly critically ill patients in the ICU

Background

The COVID-19 pandemic is a heavy burden in terms of health care resources. Future decision-making policies require consistent data on the management and prognosis of the older patients (> 70 years old) with COVID-19 admitted in the intensive care unit (ICU).

Methods

Characteristics, management, and prognosis of critically ill old patients (> 70 years) were extracted from the international prospective COVID-ICU database. A propensity score weighted-comparison evaluated the impact of intubation upon admission on Day-90 mortality.

Results

The analysis included 1199 (28% of the COVID-ICU cohort) patients (median [interquartile] age 74 [72–78] years). Fifty-three percent, 31%, and 16% were 70–74, 75–79, and over 80 years old, respectively. The most frequent comorbidities were chronic hypertension (62%), diabetes (30%), and chronic respiratory disease (25%). Median Clinical Frailty Scale was 3 (2–3). Upon admission, the PaO₂/FiO₂ ratio was 154 (105–222). 740 (62%) patients were intubated on Day-1 and eventually 938 (78%) during their ICU stay. Overall Day-90 mortality was 46% and reached 67% among the 193 patients over 80 years old. Mortality was higher in older patients, diabetics, and those with a lower PaO₂/FiO₂ ratio upon admission, cardiovascular dysfunction, and a shorter time between first symptoms and ICU admission. In propensity analysis, early intubation at ICU admission was associated with a significantly higher Day-90 mortality (42% vs 28%; hazard ratio 1.68; 95% CI 1.24–2.27; p < 0·001).

Conclusion

Patients over 70 years old represented more than a quarter of the COVID-19 population admitted in the participating ICUs during the first wave. Day-90 mortality was 46%, with dismal outcomes reported for patients older than 80 years or those intubated upon ICU admission.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00861-1.

The Impact of Aging in Acute Respiratory Distress Syndrome: A Clinical and Mechanistic Overview

Acute respiratory distress syndrome (ARDS) is associated with increased morbidity and mortality in the elderly population (≥65 years of age). Additionally, age is widely reported as a risk factor for the development of ARDS. However, the underlying pathophysiological mechanisms behind the increased risk of developing, and increased severity of, ARDS in the elderly population are not fully understood. This is compounded by the significant heterogeneity observed in patients with ARDS. With an aging population worldwide, a better understanding of these mechanisms could facilitate the development of therapies to improve outcomes in this population. In this review, the current clinical evidence of age as a risk factor and prognostic indicator in ARDS and the potential underlying mechanisms that may contribute to these factors are outlined. In addition, research on age-dependent treatment options and biomarkers, as well as future prospects for targeting these underlying mechanisms, are discussed.

Who Doesn't Come Home? Factors Influencing Mortality Among Long-Term Care Residents Transitioning to and From Emergency Departments in Two Canadian Cities

Residents of long-term care (LTC) whose deaths are imminent are likely to trigger a transfer to the emergency department (ED), which may not be appropriate. Using data from an observational study, we employed structural equation modeling to examine relationships among organizational and resident variables and death during transitions between LTC and ED. We identified 524 residents involved in 637 transfers from 38 LTC facilities and 2 EDs. Our model fit the data, (χ² = 72.91, df = 56, p = .064), explaining 15% variance in resident death. Sustained shortness of breath (SOB), persistent decreased level of consciousness (LOC) and high triage acuity at ED presentation were direct and significant predictors of death. The estimated model can be used as a framework for future research. Standardized reporting of SOB and changes in LOC, scoring of resident acuity in LTC and timely palliative care consultation for families in the ED, when they are present, warrant further investigation.

Alda-1 attenuates hyperoxia-induced mitochondrial dysfunction in lung vascular endothelial cells

Acute lung injury (ALI) is a major cause of morbidity and mortality worldwide, especially in aged populations. Mitochondrial damage is one of the key features of ALI. Hyperoxia-induced lung injury model in mice has been widely used for ALI study because it features many ALI phenotypes including, but not limited to, mitochondrial and vascular endothelial cell damage. Recently, accumulating evidence has shown that mitochondrial aldehyde dehydrogenase 2 (ALDH2) has a protective effect against oxidative stress mediated cell damage in epithelial cells. However, it is not known whether ALDH2 protects against oxidative stress in vascular endothelial cells. In this current study, we attempted to find the capacity of Alda-1 [(N-(1,3benzodioxol-5-ylmethyl)-2,6- dichloro-benzamide), an ALDH2 activator] to protect against oxidative stress in human microvascular endothelial cells (HMVEC). HMVEC pretreated with Alda-1 prior to hyperoxic exposure vs non-treated controls showed i) lower 4-hydroxynonenal (4-HNE) levels, ii) significantly decreased expressions of Bax and Cytochrome C, iii) partially restored activity and expression of ALDH2 and iv) significantly improved mitochondrial membrane potential. These results suggest that ALDH2 protein in lung vascular endothelial cells is a promising therapeutic target for the treatment of ALI and that Alda-1 is a potential treatment option.

SIRT7 deficiency suppresses inflammation, induces EndoMT, and increases vascular permeability in primary pulmonary endothelial cells

Acute lung injury (ALI), a common condition in critically ill patients, has limited treatments and high mortality. Aging is a risk factor for ALI. Sirtuins (SIRTs), central regulators of the aging process, decrease during normal aging and in aging-related diseases. We recently showed decreased SIRT7 expression in lung tissues and fibroblasts from patients with pulmonary fibrosis compared to controls. To gain insight into aging-related mechanisms in ALI, we investigated the effects of SIRT7 depletion on lipopolysaccharide (LPS)-induced inflammatory responses and endothelial barrier permeability in human primary pulmonary endothelial cells. Silencing SIRT7 in pulmonary artery or microvascular endothelial cells attenuated LPS-induced increases in ICAM1, VCAM1, IL8, and IL6 and induced endomesenchymal transition (EndoMT) with decreases in VE-Cadherin and PECAM1 and increases in collagen, alpha-smooth muscle actin, TGFβ receptor 1, and the transcription factor Snail. Loss of endothelial adhesion molecules was accompanied by increased F-actin stress fibers and increased endothelial barrier permeability. Together, these results show that an aging phenotype induced by SIRT7 deficiency promotes EndoMT with impaired inflammatory responses and dysfunction of the lung vascular barrier.

The acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a prevalent cause of acute respiratory failure with high rates of mortality, as well as short- and long-term complications, such as physical and cognitive impairment. Therefore, early recognition of this syndrome and application of well-demonstrated therapeutic interventions are essential to change the natural course of this entity and bring about positive clinical outcomes. In this article, we review updated concepts in ARDS. Specifically, we discuss the current definition of ARDS, its risk factors, and the evidence supporting ventilation management, adjunctive therapies, and interventions required in refractory hypoxemia.

Association between age and acute respiratory distress syndrome development and mortality following trauma

BACKGROUND

Improved understanding of the relationship between patient age and acute respiratory distress syndrome (ARDS) development and mortality following traumatic injury may help facilitate generation of new hypotheses about ARDS pathophysiology and the role of novel treatments to improve outcomes across the age spectrum.

METHODS

We conducted a retrospective cohort study of trauma patients included in the National Trauma Data Bank who were admitted to an intensive care unit from 2007 to 2016. We determined ARDS incidence and mortality across eight age groups for the entire 10-year study period and by year. We used generalized linear Poisson regression models adjusted for underlying mortality risk (injury mechanism, Injury Severity Score, admission Glasgow Coma Scale score, admission heart rate, and admission hypotension).

RESULTS

Acute respiratory distress syndrome occurred in 3.1% of 1,297,190 trauma encounters. Acute respiratory distress syndrome incidence was lowest among pediatric patients and highest among adults aged 35 to 64 years. Acute respiratory distress syndrome mortality was highest among patients 80 years or older (43.9%), followed by 65 to 79 years (30.6%) and 4 years or younger (25.3%). The relative risk of mortality associated with ARDS was highest among the pediatric age groups, with an adjusted relative risk (aRR) of 2.06 (95% confidence interval [CI], 1.72-2.70) among patients 4 years or younger compared with an aRR of 1.51 (95% CI, 1.42-1.62) for the entire cohort. Acute respiratory distress syndrome mortality increased over the 10-year study period (aRR, 1.03 per year; 95% CI, 1.02-1.05 per year), whereas all-cause mortality decreased (aRR, 0.98 per year; 95% CI, 0.98-0.99 per year).

CONCLUSIONS

While ARDS development following traumatic injury was most common in middle-aged adults, patients 4 years or younger and 65 years or older with ARDS experienced the highest burden of mortality. Children 4 years or younger were disproportionately affected by ARDS relative to their low underlying mortality following trauma that was not complicated by ARDS. Acute respiratory distress syndrome-associated mortality following trauma has worsened over the past decade, emphasizing the need for new prevention and treatment strategies.

LEVEL OF EVIDENCE

Prognostic/epidemiological study, level III.

The effect of blood lactate and NT-proBNP predict the survival in patients with invasive mechanical ventilation

Background

Respiratory failure is one of the most common critical diseases. It has already been reported that invasive mechanical ventilation (IMV) should be used to treat respiratory failure. The present study aims to evaluate the prognostic value of blood lactate and NT-proBNP in patients with IMV.

Methods

We retrospectively included 353 patients who were hospitalized in the emergency department of Shanghai Sixth People’s Hospital from 2016 to 2019. All patients had IMV. R&D Human Premixed Multi-Analyte Kit detected the expression of various inflammatory factors in serum. Receiver operating characteristic (ROC) curve analysis, survival analysis, and multivariate cox proportional hazards analysis were implemented as statistical analysis methods.

Results

The mean duration of hospitalization was 25.5±20.6 days. Twenty-four men and 41 women died. Compared with the survivors, the nonsurvivors were older, had different types of diagnosis, longer ventilation time, and shorter survival time (P<0.05). Also, the expression levels of PCT, NT-proBNP, lactate in 12 h and lactate in 24 h in the nonsurvivors were significantly higher than those in the survivor group (P<0.05). There was a significant correlation between these parameters and ventilation times (P<0.001). The results showed that age, NT-proBNP, and lactate were independent predictors of survival rate. ROC analysis showed that the cut-off values of age, NT-proBNP and lactate were 61.5 years, 230.5 pg/mL and 3.7 mmol/L, respectively. Patients aged ≥61.5 years or NT-proBNP ≥230.5 pg/mL or lactate ≥3.7 mmol/L had a worse prognosis. Therefore, patients with three parameters higher than cut-off value had the lowest survival rate, while patients with three parameters lower than cut-off value had the best survival rate.

Conclusions

Blood lactate and NT-proBNP may be used as biomarkers to predict the prognosis of patients undergoing IMV.

Impact of Long-Term Exposures to Ambient PM2.5 and Ozone on ARDS Risk for Older Adults in the United States

BACKGROUND

Chronic exposures to particulate matter with an aerodynamic diameter < 2.5 μm (PM_2.5) and ozone pollution can affect respiratory function. ARDS, an often lethal respiratory failure, is most common among older adults. However, few epidemiology studies have investigated an association between air pollution and the risk of ARDS.

METHODS

This observational study was conducted to estimate air pollution exposures at the ZIP code level and hospital admissions with ARDS among US Medicare beneficiaries aged ≥ 65 years from 2000 to 2012. A two-pollutant generalized linear mixed model, adjusting for sex, age, race, median household income, smoking, and weather, was applied.

RESULTS

There were a total of 1,164,784 hospital admissions with ARDS in the cohort. Increases of 1 µg/m³ in annual average PM_2.5 and of 1 parts per billion in annual average ozone were associated with increases in annual hospital admission rates for ARDS of 0.72% (95% CI, 0.62-0.82) and 0.15% (95% CI, 0.08-0.22), respectively. In low-pollution regions (annual average PM_2.5 level < 12 µg/m³ and annual average ozone level < 45 parts per billion), the same annual increase in PM_2.5 and ozone were associated with increases in annual hospital admission rates for ARDS of 1.50% (95% CI, 1.27-1.72) and 0.27% (95% CI, 0.16-0.38).

CONCLUSIONS

Long-term exposures to PM_2.5 and ozone were associated with increased risk of ARDS among older adults in the United States, including exposures below current annual US National Ambient Air Quality Standards.

Survival predictors in elderly patients with acute respiratory distress syndrome: a prospective observational cohort study

Acute respiratory distress syndrome (ARDS) has a high mortality rate in intensive care units (ICU). The elderly patients remain to be increased of ICU patients. The aim is to investigate the survival predictors of elderly patients with ARDS. We reported a prospective observational cohort research, including the patients with ARDS between October 2012 and May 2015. Demographic, comorbidities, severity, lung mechanics, laboratory data and survival outcomes were analyzed. A total of 463 patients with ARDS were ≥65 years old were enrolled and analyzed. Multivariate logistic regression analysis identified Charlson comorbidity index (CCI) [odds ratio (OR) 1.111, 95% CI 1.010–1.222, p = 0.031], Sequential Organ Failure Assessment (SOFA) score (OR 1.127, 95% CI 1.054–1.206, p < 0.001) and peak inspiratory pressure (PIP) (OR 1.061, 95% CI 1.024–1.099, p = 0.001) which were independently associated with hospital mortality. Regarding the subgroups patients as 65–74 years old, 75–84 years old and ≥85 years old, the baseline characteristics were not significant difference and the hospital mortality rates were also not significant difference. In conclusion, CCI, SOFA score and PIP were identified as survival predictors in elderly patient with ARDS. Assessing comorbidities with CCI is essential in predicting the survival for elderly patients with ARDS.

Caring for critically ill oldest old patients: a clinical review

Despite technological advances, the mortality rate for critically ill oldest old patients remains high. The intensive caring should be able to combine technology and a deep humanity considering that the patients are living the last part of their lives. In addition to the traditional goals of ICU of reducing morbidity and mortality, of maintaining organ functions and restoring health, caring for seriously oldest old patients should take into account their end-of-life preferences, the advance or proxy directives if available, the prognosis, the communication, their life expectancy and the impact of multimorbidity. The aim of this review was to focus on all these aspects with an emphasis on some intensive procedures such as mechanical ventilation, noninvasive mechanical ventilation, cardiopulmonary resuscitation, renal replacement therapy, hemodynamic support, evaluation of delirium and malnutrition in this heterogeneous frail ICU population.

Timing of valproic acid in acute lung injury: prevention is the best therapy?

BACKGROUND

Acute lung injury and respiratory distress syndrome is characterized by uncontrolled inflammation of the lungs after a severe inflammatory stimulus. We have previously demonstrated an ameliorated syndrome and improved survival in mice with early administration of valproic acid (VPA), a broad-spectrum histone deacetylase inhibitor, while studies in humans have shown no benefit when anti-inflammatories are administered late. The current study tested the hypothesis that early treatment would improve outcomes in our gram-negative pneumonia-induced acute lung injury.

MATERIALS AND METHODS

Mice (C57BL/6) had 50 × 10⁶ Escherichia coli (strain 19,138) instilled endotracheally and VPA (250 mg/kg) administered intraperitoneally 3, 4, 6, and 9 h (n = 12/group) later. Six hours after VPA administration, the animals were sacrificed, and bronchoalveolar lavage (BAL) fluid interleukin-6 (IL-6), tumor necrosis factor, neutrophils and macrophages as well as the E coli colony-forming units were quantified. Plasma IL-6 was also measured. A separate group of mice (n = 12/group) were followed prospectively for 7 days to assess survival.

RESULTS

BAL IL-6 and tumor necrosis factor as well as plasma IL-6 were significantly lower in the animals administered VPA within 3 h (P < 0.05) but not when administered later (4, 6, 9 h). There was no difference in the BAL E coli colony-forming units, macrophage, or neutrophil numbers at any time point. Survival improved only when VPA was administered within 3 h.

CONCLUSIONS

A narrow therapeutic window exists in this murine model of gram-negative pneumonia-induced acute lung injury and likely explains the lack of response in studies with late administration of anti-inflammatory therapies in clinical studies.

Curcumin inhibits lipopolysaccharide (LPS)-induced endotoxemia and airway inflammation through modulation of sequential release of inflammatory mediators (TNF-α and TGF-β1) in murine model

OBJECTIVE

Curcumin (diferuloylmethane), a major component of turmeric is well known for its anti-inflammatory potential. Present study investigates sequential release of inflammatory mediators post LPS challenge (10 mg/kg,i.p.) causing lung inflammation and its modulation by curcumin through different routes (20 mg/kg, i.p and 10 mg/kg, i.n.) in murine model. Dexamethasone (1 mg/kg, i.p) was used as standard drug.

METHODS

Lung Inflammation was evaluated by histopathological analysis, myeloperoxidase (MPO) activity followed by inflammatory cell count and total protein content measurements in bronchoalveolar fluid (BALF). Reactive oxygen species (ROS), nitrite and TNF-α levels were measured as markers of endotoxin shock at different time points (1-72 h). The mRNA expression of transforming growth factors-β1 (TGF-β1), iNOS and Toll-like receptor-4 (TLR-4) were measured followed by Masson's trichrome staining and hydroxyproline levels as collagen deposition marker leading to fibrotic changes in lungs.

RESULTS

We found that LPS-induced lung inflammation and injury was maximum 24-h post LPS challenge shown by MPO and histological analysis which was further supported by elevated nitrite and ROS levels whereas TNF-α level was highest after 1 h. Endotoxin-induced mortality was significantly reduced in curcumin (i.p) pretreatment groups up to 72-h post LPS challenge. Significant inhibition in mRNA expression of iNOS, TGF-β1 and TNF-α level was noted after curcumin treatment along with lowered MPO activity, inflammatory cell count, ROS, nitrite levels and collagen deposition in lungs.

CONCLUSION

Our results suggest that higher endotoxin dose causes inflammatory mediator release in chronological order which tend to increase with time and reached maximum after 24-h post-endotoxin (LPS) exposure. Intraperitoneal route of curcumin administration was better in modulating inflammatory mediator release in early phase as compared to intranasal route of administration. It can be used as supplementary therapeutic intervention at early stage of endotoxemia, having fewer side effects.

Epidemiological profile of acute respiratory distress syndrome patients: A tertiary care experience

Background:

Acute respiratory distress syndrome (ARDS) is seen in critically ill patients. Its etiological spectrum in India is expected to be different from that seen in western countries due to the high prevalence of tropical infections.

Aim:

To study the epidemiological profile of ARDS patients.

Setting:

A tertiary care hospital in Karnataka, India.

Materials and Methods:

Retrospective analysis of 150 out of the 169 ARDS patients diagnosed during 2010–2012. Data collected included the clinical features and severity scoring parameters.

Results:

The mean age of the study population was 42.92 ± 13.91 years. The causes of ARDS included pneumonia (n = 35, 23.3%), scrub typhus (n = 33, 22%), leptospirosis (n = 11, 7.3%), malaria (n = 6, 4%), influenza (H1N1) (n = 10, 6.7%), pulmonary tuberculosis (n = 2, 1.3%), dengue (n = 1, 0.7%), abdominal sepsis (n = 16, 10.7%), skin infection (n = 3, 2%), unknown cause of sepsis (n = 18, 12%), and nonseptic causes (n = 15, 10%). A total of 77 (51.3%) patients survived, 66 (44%) expired, and 7 (4.7%) were discharged against medical advice (AMA). Preexisting comorbidities (46) were present in 13 survivors, 19 nonsurvivors, and four discharged AMA. History of surgery prior to the onset of ARDS was present in one survivor, 13 nonsurvivors, and one discharge AMA. Mean Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE III, and Sequential Organ Failure Assessment scores in survivors were 9.06 ± 4.3, 49.22 ± 14, and 6.43 ± 2.5 and in nonsurvivors 21.11 ± 7, 86.45 ± 23.5, and 10.6 ± 10, respectively.

Conclusion:

The most common cause of ARDS in our study was pneumonia, but a large percentage of cases were due to the tropical infections. Preexisting comorbidity, surgery prior to the onset of ARDS, higher severity scores, and organ failure scores were more frequently observed among nonsurvivors than survivors.

Aging and Lung Disease. Clinical Impact and Cellular and Molecular Pathways

With the expected rapid growth of the aging population worldwide, there is a clear need to understand the complex process of aging to develop interventions that might extend the health span in this group of patients. Aging is associated with increased susceptibility to a variety of chronic diseases, and lung pathologies are no exception. The prevalence of lung diseases such as idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease has been found to increase considerably with age. In October 2014, the Division of Pulmonary, Allergy, and Critical Care of the University of Pittsburgh cohosted the Pittsburgh-Munich Lung Conference focused in aging and lung disease with the Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Ludwig-Maximilians University and Helmholtz Zentrum Munich Germany. The purpose of the conference was to disseminate novel concepts in aging mechanisms that have an impact in lung physiology and pathogenesis of pulmonary diseases that commonly occur in older populations. The conference included 28 presentations on diverse topics, which are summarized in this report. The participants identified priorities for future basic and translational investigations that will assist in the identification of molecular insights involved in the pathogenesis of age-related pulmonary diseases and the design of therapeutic interventions for these lung conditions.

[Extracorporeal pulmonary support procedures in intensive care medicine 2014]

BACKGROUND

In recent years a rapid expansion of extracorporeal devices for support of severe lung failure has been witnessed. Systems for veno-venous extracorporeal membrane oxygenation (VV-ECMO) or for extracorporeal carbon dioxide elimination are distinguished depending on the indications.

OBJECTIVES

The state of the art of extracorporeal lung support is presented with an overview of the different systems, the indications, efficiency and potential side effects.

METHODS

By means of a selective literature research and based on personal experience, the principles and techniques, efficiency and potential side-effects of the new modalities are described.

RESULTS

The VV-ECMO systems may be indicated in severe, refractory and predominantly hypoxemic lung failure (pAO2/FIO2 <80 mmHg). Both life-saving gas exchange and a reduction of ventilator-induced lung injury by means of a more protective ventilation can be achieved. Experienced centers can obtain survival rates of more than 60%. Either pumpless arterio-venous devices, also called interventional lung assist (ILA) or low-flow ECMO devices can be used for extracorporeal carbon dioxide elimination in refractory respiratory acidosis. Severe complications can occur with all modalities of extracorporeal support and have to be rapidly recognized and controlled. It must be pointed out that secure evidence based on prospective randomized studies is currently limited for all modalities.

CONCLUSION

Modern extracorporeal lung support devices allow an effective extracorporeal gas exchange and have become an inherent component of intensive care treatment of critically ill patients. Due to potentially severe complications the use should be restricted to specialized centers with experience in the treatment of severe acute respiratory distress syndrome (ARDS).

The acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is a major cause of acute respiratory failure. Its development leads to high rates of mortality, as well as short- and long-term complications, such as physical and cognitive impairment. Therefore, early recognition of this syndrome and application of demonstrated therapeutic interventions are essential to change the natural course of this devastating entity. In this review article, we describe updated concepts in ARDS. Specifically, we discuss the new definition of ARDS, its risk factors and pathophysiology, and current evidence regarding ventilation management, adjunctive therapies, and intervention required in refractory hypoxemia.

Influence of hyperoxia and mechanical ventilation in lung inflammation and diaphragm function in aged versus adult rats

Although assist ventilation with FIO2 0.21 is the preferable mode of ventilation in the intensive care unit, sometimes controlled ventilation with hyperoxia is needed. But the impact of this setting has not been extensively studied in elderly subjects. We hypothesized that a high fraction of inspired oxygen (FiO(2)) and controlled mechanical ventilation (CMV) is associated with greater deleterious effects in old compared to adult subjects. Adult and old rats were submitted to CMV with low tidal volume (6 ml/kg) and FiO(2) 1 during 3 or 6 h. Arterial blood gas samples were measured at 0, 60 and 180 min (four groups: old and adult rats, 3 or 6 h of CMV), and additionally at 360 min (two groups: old and adult rats, 6 h of CMV). Furthermore, total protein content (TPC) and tumor necrosis factor-alpha (TNF-α) in bronchoalveolar lavage were assessed; lung tissue was used for malondialdehyde and histological analyses, and the diaphragm for measurement of contractile function. Arterial blood gas analysis showed an initial (60 min) greater PaO(2) in elderly versus adult animals; after that time, elderly animals had lowers pH and PaO(2), and greater PaCO(2). After 3 h of CMV, TPC and TNF-α levels were higher in the old compared with the adult group (P < 0.05). After 6 h of MV, malondialdehyde was significantly higher in elderly compared with the adult animals (P < 0.05). Histological analysis showed leukocyte infiltration and edema, greater in old animals. In diaphragm, twitch contraction with caffeine significantly declined after 6 h of CMV only for the elderly group. These data support the hypothesis that relatively short-term CMV with low tidal volume and hyperoxia has greatest impact in elderly rats, decreasing diaphragmatic contractile function and increasing lung inflammation.

High-frequency oscillatory ventilation for cardiac surgery children with severe acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) in children after open heart surgery, although uncommon, can be a significant source of morbidity. Because high-frequency oscillatory ventilation (HFOV) had been used successfully with pediatric patients who had no congenital heart defects, this therapy was used in our unit. This report aims to describe a single-center experience with HFOV in the management of ARDS after open heart surgery with respect to mortality. This retrospective clinical study was conducted in a pediatric intensive care unit. From October 2008 to August 2012, 64 of 10,843 patients with refractory ARDS who underwent corrective surgery at our institution were ventilated with HFOV. Patients with significant uncorrected residual lesions were not included. No interventions were performed. The patients were followed up until hospital discharge. The main outcome measure was survival to hospital discharge. Severe ARDS was defined as acute-onset pulmonary failure with bilateral pulmonary infiltrates and an oxygenation index (OI) higher than 13 despite maximal ventilator settings. The indication for HFOV was acute severe ARDS unresponsive to optimal conventional treatment. The variables recorded and subjected to multivariate analysis were patient demographics, underlying disease, clinical data, and ventilator parameters and their association with hospital mortality. Nearly 10,843 patients underwent surgery during the study period, and the ARDS incidence rate was 0.76 % (83/10,843), with 64 patients (77 %, 64/83) receiving HFOV. No significant changes in systemic or central venous pressure were associated with initiation and maintenance of HFOV. The complications during HFOV included pneumothorax for 22 patients. The overall in-hospital mortality rate was 39 % (25/64). Multiple regression analyses indicated that pulmonary hypertension and recurrent respiratory tract infections (RRTIs) before surgery were independent predictors of in-hospital mortality. The findings show that HFOV is an effective and safe method for ventilating severe ARDS patients after corrective cardiac surgery. Pulmonary hypertension and RRTIs before surgery were risk factors for in-hospital mortality.

Creation of lung-targeted dexamethasone immunoliposome and its therapeutic effect on bleomycin-induced lung injury in rats

OBJECTIVE

Acute lung injury (ALI), is a major cause of morbidity and mortality, which is routinely treated with the administration of systemic glucocorticoids. The current study investigated the distribution and therapeutic effect of a dexamethasone(DXM)-loaded immunoliposome (NLP) functionalized with pulmonary surfactant protein A (SP-A) antibody (SPA-DXM-NLP) in an animal model.

METHODS

DXM-NLP was prepared using film dispersion combined with extrusion techniques. SP-A antibody was used as the lung targeting agent. Tissue distribution of SPA-DXM-NLP was investigated in liver, spleen, kidney and lung tissue. The efficacy of SPA-DXM-NLP against lung injury was assessed in a rat model of bleomycin-induced acute lung injury.

RESULTS

The SPA-DXM-NLP complex was successfully synthesized and the particles were stable at 4°C. Pulmonary dexamethasone levels were 40 times higher with SPA-DXM-NLP than conventional dexamethasone injection. Administration of SPA-DXM-NLP significantly attenuated lung injury and inflammation, decreased incidence of infection, and increased survival in animal models.

CONCLUSIONS

The administration of SPA-DXM-NLP to animal models resulted in increased levels of DXM in the lungs, indicating active targeting. The efficacy against ALI of the immunoliposomes was shown to be superior to conventional dexamethasone administration. These results demonstrate the potential of actively targeted glucocorticoid therapy in the treatment of lung disease in clinical practice.

Extracorporeal pulmonary support in severe pulmonary failure in adults: a treatment rediscovered

BACKGROUND

Severe, acute respiratory failure in adults still carries a high mortality. In recent years, improved pulmonary support techniques have been used increasingly alongside conventional treatment. About 1000 such treatments are performed in Germany annually, and the number is rising rapidly. The two types of systems currently in use involve venovenous extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide elimination.

METHODS

The underlying principles, technical implementation, efficacy, and adverse effects of the new techniques are summarized in the light of a selective review of the literature, supplemented by the authors' personal experience. Recommendations are given for clinical use.

RESULTS

Currently, only limited high-quality data (from prospective randomized trials) are available to support the use of either of these techniques in adults. Veno-venous ECMO systems can effectively secure gas exchange in patients with severe respiratory failure, with experienced centers reporting survival rates from 63% to 75%. Either pump-free arteriovenous systems or low-flow ECMO systems can be used for extracorporeal carbon dioxide elimination. Complications can be serious or life-threatening and must, therefore, be rapidly recognized and treated: these include vascular injury during cannulation, venous thrombosis in a cannulated vessel, an increased hemorrhagic tendency, and thrombocytopenia.

CONCLUSION

Modern miniaturized pulmonary support systems enable protective mechanical ventilation with low tidal volumes, reduce ventilator-associated lung injury, and can improve survival rates in critically ill patients with a manageable adverse effect profile.

Combined APACH II score and arterial blood lactate clearance rate to predict the prognosis of ARDS patients

OBJECTIVE

To explore the easily applicable indicators of practical value to evaluate the prognosis of acute respiratory distress syndrome (ARDS).

METHODS

Blood and biochemical tests and blood-gas analyses were performed upon entry into the ICUs, 12 h, 24 h, 48 h and 72 h after that in 72 ARDS patients (who were admitted to the ICUs of our hospital from January 2000 to December 2009). Then APACHE II scores were achieved by combining relevant physiological parameters and laboratory results.

RESULTS

There was a statistical difference between the death group and survival group at different time points upon entering the ICUs in terms of APACHE II score, alveolar-arterial oxygen difference and arterial blood lactate clearance rate. PaO(2)/FiO(2) values were recorded to be statistically different between the death group and survival group 24 h, 48 h and 72 h, respectively after entry into the ICUs. In addition, registered linear regression existed between APACHE II score, alveolar-arterial oxygen difference or PaO(2)/FiO(2) value and time. APACHE II score 24 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve (AUC) standing respectively at 0.919 and 0.955. Arterial blood lactate clearance rate 12 h, 24 h, 48 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve (AUC) at 0.918, 0.918, 0.909 and 0.991, respectively.

CONCLUSIONS

APACHE II score applied in combination with arterial blood lactate clearance rate is of clinical significance in assessing the prognosis of ARDS patients.

Short courses of mechanical ventilation with high-O2 levels in elderly rat lungs

PURPOSE

To evaluate the effects of mechanical ventilation (MV) of high-oxygen concentration in pulmonary dysfunction in adult and elderly rats.

METHODS

Twenty-eight adult (A) and elderly (E), male rats were ventilated for 1 hour (G-AV1 and G-EV1) or for 3 hours (G-AV3 and G-EV3). A and E groups received a tidal volume of 7 mL/kg, a positive end-expiratory pressure of 5 cm H2O, respiratory rate of 70 cycles per minute, and an inspiratory fraction of oxygen of 1. We evaluated total protein content and malondialdehyde in bronchoalveolar lavages (BAL) and performed lung histomorphometrical analyses.

RESULTS

In G-EV1 animals, total protein in BAL was higher (33.0±1.9 µg/mL) compared with G-AV1 (23.0±2.0 µg/mL). Upon 180 minutes of MV, malondialdehyde levels increased in elderly (G-EV3) compared with adult (G-AV3) groups. Malondialdehyde and total proteins in BAL after 3 hours of MV were higher in elderly group than in adults. In G-EV3 group we observed alveolar septa dilatation and significative increase in neutrofiles number in relation to adult group at 60 and 180 minutes on MV.

CONCLUSION

A higher fraction of inspired oxygen in short courses of mechanical ventilation ameliorates the parameters studied in elderly lungs.

Acute respiratory distress syndrome: pathophysiology and therapeutic options

Acute Respiratory Distress Syndrome (ARDS) is a common entity in critical care. ARDS is associated with many diagnoses, including trauma and sepsis, can lead to multiple organ failure and has high mortality. The present article is a narrative review of the literature on ARDS, including ARDS pathophysiology and therapeutic options currently being evaluated or in use in clinical practice. The literature review covers relevant publications until January 2011. Recent developments in the therapeutic approach to ARDS include refinements of mechanical ventilatory support with emphasis on protective lung ventilation using low tidal volumes, increased PEEP with use of recruitment maneuvers to promote reopening of collapsed lung alveoli, prone position as rescue therapy for severe hypoxemia, and high frequency ventilation. Supportive measures in the management of ARDS include attention to fluid balance, restrictive transfusion strategies, and minimization of sedatives and neuromuscular blocking agents. Inhaled bronchodilators such as inhaled nitric oxide and prostaglandins confer short term improvement without proven effect on survival, but are currently used in many centers. Use of corticosteroids is also important, and appropriate timely use may reduce mortality. Finally, extra corporeal oxygenation methods are very useful as rescue therapy in patients with intractable hypoxemia, even though a survival benefit has not, to this date been demonstrated. Despite intense ongoing research on the pathophysiology and treatment of ARDS, mortality remains high. Many pharmacologic and supportive strategies have shown promising results, but data from large randomized clinical trials are needed to fully evaluate the true effectiveness of these therapies.