Incidence and mortality after acute respiratory failure and acute respiratory distress syndrome in Sweden, Denmark, and Iceland. The ARF Study Group

Acute respiratory distress syndrome: epidemiology and management approaches

Acute lung injury and the more severe acute respiratory distress syndrome represent a spectrum of lung disease characterized by the sudden onset of inflammatory pulmonary edema secondary to myriad local or systemic insults. The present article provides a review of current evidence in the epidemiology and treatment of acute lung injury and acute respiratory distress syndrome, with a focus on significant knowledge gaps that may be addressed through epidemiologic methods.

Trends in the incidence of noncardiogenic acute respiratory failure: the role of race

OBJECTIVE

We sought to examine trends in the race-specific incidence of acute respiratory failure in the United States.

DESIGN

Retrospective cohort study.

SETTING

We used the National Hospital Discharge Survey database (1992-2007), an annual survey of approximately 500 hospitals weighted to provide national hospitalization estimates.

PATIENTS

All incident cases of noncardiogenic acute respiratory failure hospitalized in the United States.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified noncardiogenic acute respiratory failure by the presence of International Classification of Diseases, Ninth Revision, codes for respiratory failure or pulmonary edema (518.4, 518.5, 518.81, and 518.82) and mechanical ventilation (96.7×), excluding congestive heart failure. Incidence rates were calculated using yearly census estimates standardized to the age and sex distribution of the 2000 census population. Annual cases of noncardiogenic acute respiratory failure increased from 86,755 in 1992 to 323,474 in 2007. Noncardiogenic acute respiratory failure among black Americans increased from 56.4 (95% confidence interval 39.7-73.1) to 143.8 (95% confidence interval 123.8-163.8) cases per 100,000 in 1992 and 2007, respectively. Among white Americans, the incidence of noncardiogenic acute respiratory failure increased from 31.2 (95% confidence interval 26.2-36.5) to 94.0 (95% confidence interval 86.7-101.2) cases per 100,000 in 1992 and 2007, respectively. The average annual incidence of noncardiogenic acute respiratory failure over the entire study period was 95.1 (95% confidence interval 93.9-96.4) cases per 100,000 for black Americans compared to 66.5 (95% confidence interval 65.8-67.2) cases per 100,000 for white Americans (rate ratio 1.43, 95% confidence interval 1.42-1.44). Overall in-hospital mortality was greater for other-race Americans, but only among patients with two or more organ failures (57% [95% confidence interval 56%-59%] for other race, 51% [95% confidence interval 50%-52%] for white, 50% [95% confidence interval 49%-51%] for black).

CONCLUSIONS

The incidence of noncardiogenic acute respiratory failure in the United States increased between 1992 and 2007. Black and other-race Americans are at greater risk of developing noncardiogenic acute respiratory failure compared to white Americans.

A systematic review of validated methods for identifying acute respiratory failure using administrative and claims data

PURPOSE

The Food and Drug Administration's (FDA) Mini-Sentinel pilot program initially aims to conduct active surveillance to refine safety signals that emerge for marketed medical products. A key facet of this surveillance is to develop and understand the validity of algorithms for identifying health outcomes of interest (HOIs) from administrative and claims data. This paper summarizes the process and findings of the algorithm review of acute respiratory failure (ARF).

METHODS

PubMed and Iowa Drug Information Service searches were conducted to identify citations applicable to the anaphylaxis HOI. Level 1 abstract reviews and Level 2 full-text reviews were conducted to find articles using administrative and claims data to identify ARF, including validation estimates of the coding algorithms.

RESULTS

Our search revealed a deficiency of literature focusing on ARF algorithms and validation estimates. Only two studies provided codes for ARF, each using related yet different ICD-9 codes (i.e., ICD-9 codes 518.8, "other diseases of lung," and 518.81, "acute respiratory failure"). Neither study provided validation estimates.

CONCLUSIONS

Research needs to be conducted on designing validation studies to test ARF algorithms and estimating their predictive power, sensitivity, and specificity.

Heart rate-corrected QT interval helps predict mortality after intentional organophosphate poisoning

Introduction

In this study, we investigated the outcomes for patients with intentional organophosphate poisoning. Previous reports indicate that in contrast to normal heart rate-corrected QT intervals (QTc), QTc prolongation might be indicative of a poor prognosis for patients exposed to organophosphates.

Methods

We analyzed the records of 118 patients who were referred to Chang Gung Memorial Hospital for management of organophosphate poisoning between 2000 and 2011. Patients were grouped according to their initial QTc interval, i.e., normal (<0.44 s) or prolonged (>0.44 s). Demographic, clinical, laboratory, and mortality data were obtained for analysis.

Results

The incidence of hypotension in patients with prolonged QTc intervals was higher than that in the patients with normal QTc intervals (P = 0.019). By the end of the study, 18 of 118 (15.2%) patients had died, including 3 of 75 (4.0%) patients with normal QTc intervals and 15 of 43 (34.9%) patients with prolonged QTc intervals. Using multivariate-Cox-regression analysis, we found that hypotension (OR = 10.930, 95% CI = 2.961–40.345, P = 0.000), respiratory failure (OR = 4.867, 95% CI = 1.062–22.301, P = 0.042), coma (OR = 3.482, 95% CI = 1.184–10.238, P = 0.023), and QTc prolongation (OR = 7.459, 95% CI = 2.053–27.099, P = 0.002) were significant risk factors for mortality. Furthermore, it was revealed that non-survivors not only had longer QTc interval (503.00±41.56 versus 432.71±51.21 ms, P = 0.002), but also suffered higher incidences of hypotension (83.3 versus 12.0%, P = 0.000), shortness of breath (64 versus 94.4%, P = 0.010), bronchorrhea (55 versus 94.4%, P = 0.002), bronchospasm (50.0 versus 94.4%, P = 0.000), respiratory failure (94.4 versus 43.0%, P = 0.000) and coma (66.7 versus 11.0%, P = 0.000) than survivors. Finally, Kaplan-Meier analysis demonstrated that cumulative mortality was higher among patients with prolonged QTc intervals than among those with normal QTc intervals (Log-rank test, Chi-square test = 20.36, P<0.001).

Conclusions

QTc interval helps predict mortality after intentional organophosphate poisoning.

A simple classification model for hospital mortality in patients with acute lung injury managed with lung protective ventilation

OBJECTIVE

Despite improvements in the care of critically ill patients, hospital mortality rate for acute lung injury remains high at approximately 40%. We developed a classification rule to stratify mechanically ventilated patients with acute lung injury according to hospital mortality and compared this rule with the Acute Physiology and Chronic Health Evaluation III prediction.

PATIENTS

We used data of 2,022 participants in Acute Respiratory Distress Syndrome Network trials to build a classification rule based on 54 variables collected before randomization.

DESIGN

We used a classification tree approach to stratify patients according to hospital mortality using a training subset of 1800 participants and estimated expected prediction errors using tenfold crossvalidation. We validated our classification tree using a subset of 222 participants not included in model building and calculated areas under the receiver operating characteristic curves.

MEASUREMENTS AND MAIN RESULTS

We identified combinations of age (>63 yrs), blood urea nitrogen (>15 mg/dL), shock, respiratory rate (>21 breaths/min), and minute ventilation (>13.9 L/min) as important predictors of hospital mortality at 90 days. The classification tree had a similar expected prediction error in the training set (28% vs. 26%; p = .18) and areas under the receiver operating characteristic curve in the validation set (0.71 vs. 0.73; p = .71) as did a model based on Acute Physiology and Chronic Health Evaluation III.

CONCLUSIONS

Our tree-based classification rule performed similarly to Acute Physiology and Chronic Health Evaluation III in stratifying patients according to hospital mortality, is simpler to use, contains risk factors that may be specific to acute lung injury, and identified minute ventilation as a potential novel predictor of death in patients with acute lung injury.

Epidemiology of ARDS and ALI

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are distinctly modern clinical entities. Recent epidemiologic research has taken advantage of large cohorts in efforts to better describe these highly lethal syndromes with a focus on differentiation of clinically meaningful subtypes and early prediction in an effort to improve treatment and prevention. This article identifies the most significant studies and systematic reviews of recent years, defining the incidence, mortality, risk and prognostic factors, and etiologic classes of ARDS/ALI.

Extracorporeal membrane oxygenation for ARDS in adults

A 41-year-old woman presents with severe community-acquired pneumococcal pneumonia. Chest radiography reveals diffuse bilateral infiltrates, and hypoxemic respiratory failure develops despite appropriate antibiotic therapy. She is intubated and mechanical ventilation is initiated with a volume- and pressure-limited approach for the acute respiratory distress syndrome (ARDS). Over the ensuing 24 hours, her partial pressure of arterial oxygen (Pao2) decreases to 40 mm Hg, despite ventilatory support with a fraction of inspired oxygen (Fio2) of 1.0 and a positive end-expiratory pressure (PEEP) of 20 cm of water. She is placed in the prone position and a neuromuscular blocking agent is administered, without improvement in her Pao2. An intensive care specialist recommends the initiation of extracorporeal membrane oxygenation (ECMO).

The ALIEN study: incidence and outcome of acute respiratory distress syndrome in the era of lung protective ventilation

PURPOSE

While our understanding of the pathogenesis and management of acute respiratory distress syndrome (ARDS) has improved over the past decade, estimates of its incidence have been controversial. The goal of this study was to examine ARDS incidence and outcome under current lung protective ventilatory support practices before and after the diagnosis of ARDS.

METHODS

This was a 1-year prospective, multicenter, observational study in 13 geographical areas of Spain (serving a population of 3.55 million at least 18 years of age) between November 2008 and October 2009. Subjects comprised all consecutive patients meeting American-European Consensus Criteria for ARDS. Data on ventilatory management, gas exchange, hemodynamics, and organ dysfunction were collected.

RESULTS

A total of 255 mechanically ventilated patients fulfilled the ARDS definition, representing an incidence of 7.2/100,000 population/year. Pneumonia and sepsis were the most common causes of ARDS. At the time of meeting ARDS criteria, mean PaO(2)/FiO(2) was 114 ± 40 mmHg, mean tidal volume was 7.2 ± 1.1 ml/kg predicted body weight, mean plateau pressure was 26 ± 5 cmH(2)O, and mean positive end-expiratory pressure (PEEP) was 9.3 ± 2.4 cmH(2)O. Overall ARDS intensive care unit (ICU) and hospital mortality was 42.7% (95%CI 37.7-47.8) and 47.8% (95%CI 42.8-53.0), respectively.

CONCLUSIONS

This is the first study to prospectively estimate the ARDS incidence during the routine application of lung protective ventilation. Our findings support previous estimates in Europe and are an order of magnitude lower than those reported in the USA and Australia. Despite use of lung protective ventilation, overall ICU and hospital mortality of ARDS patients is still higher than 40%.

Prone and ECMO - a contradiction per se?

Acute respiratory distress syndrome (ARDS) still represents a serious problem in clinical routine and is associated with a high mortality. Several concepts are known for special treatment, but, in some instances, the application of an extracorporeal membrane oxygenation (ECMO) is necessary for both the improvement of oxygenation and the elimination of carbon dioxide (CO(2)). One basic aspect in lung protective ventilation in this context is alveolar recruitment, which can be achieved by different approaches, such as "the open lung concept", according to Lachmann, or by additional kinetic therapy. The most exposed feature of this entity is 'prone', which may be quite challenging in patients requiring extracorporeal support or organ replacement therapy under ongoing critical illness. We report two outstanding cases of prone under conditions of a veno-venous ECMO therapy which improved significantly under this position. Furthermore, we reflect critically possible risk factors and adverse events of such procedures and afford a current view from the literature.

Lung sonography and recruitment in patients with early acute respiratory distress syndrome: a pilot study

INTRODUCTION

Bedside lung sonography is a useful imaging tool to assess lung aeration in critically ill patients. The purpose of this study was to evaluate the role of lung sonography in estimating the nonaerated area changes in the dependent lung regions during a positive end-expiratory pressure (PEEP) trial of patients with early acute respiratory distress syndrome (ARDS).

METHODS

Ten patients (mean ± standard deviation (SD): age 64 ± 7 years, Acute Physiology and Chronic Health Evaluation II (APACHE II) score 21 ± 4) with early ARDS on mechanical ventilation were included in the study. Transthoracic sonography was performed in all patients to depict the nonaerated area in the dependent lung regions at different PEEP settings of 5, 10 and 15 cm H2O. Lung sonographic assessment of the nonaerated lung area and arterial blood gas analysis were performed simultaneously at the end of each period. A control group of five early ARDS patients matched for APACHE II score was also included in the study.

RESULTS

The nonaerated areas in the dependent lung regions were significantly reduced during PEEP increases from 5 to 10 to 15 cm H2O (27 ± 31 cm2 to 20 ± 24 cm2 to 11 ± 12 cm2, respectively; P < 0.01). These changes were associated with a significant increase in arterial oxygen partial pressure (74 ± 15 mmHg to 90 ± 19 mmHg to 102 ± 26 mmHg; P < 0.001, respectively). No significant changes were observed in the nonaerated areas in the dependent lung regions in the control group.

CONCLUSIONS

In this study, we show that transthoracic lung sonography can detect the nonaerated lung area changes during a PEEP trial of patients with early ARDS. Thus, transthoracic lung sonography might be considered as a useful clinical tool in the management of ARDS patients.

Mortality and associated factors in a thoracic surgery ICU

OBJECTIVE

To assess mortality and identify mortality risk factors in patients admitted to a thoracic surgery ICU.

METHODS

We retrospectively evaluated 141 patients admitted to the thoracic surgery ICU of the Denizli State Hospital, located in the city of Denizli, Turkey, between January of 2006 and August of 2008. We collected data regarding gender, age, reason for admission, invasive interventions and operations, invasive mechanical ventilation, infections, and length of ICU stay.

RESULTS

Of the 141 patients, 103 (73.0%) were male, and 38 (23.0%) were female. The mean age was 52.1 years (range, 12-92 years), and the mortality rate was 16.3%. The most common reason for admission was trauma. Mortality was found to correlate with advanced age (p < 0.05), requiring invasive mechanical ventilation (OR = 42.375; p < 0.05), prolonged ICU stay (p < 0.05), and specific reasons for admission-trauma, gunshot wound, stab wound, and malignancy (p < 0.05 for all).

CONCLUSIONS

Among patients in a thoracic surgery ICU, the rates of morbidity and mortality are high. Increased awareness of mortality risk factors can improve the effectiveness of treatment, which should reduce the rates of morbidity and mortality, thereby providing time savings and minimizing costs.

Serum zinc in critically ill adult patients with acute respiratory failure

BACKGROUND AND AIMS

Zinc deficiency leads to susceptibility to infections and may affect pulmonary epithelial cell integrity. Low zinc levels have also been associated with a degree of organ failure and decreased survival in critically ill children. Accordingly, the purpose of the study was to assess serum zinc in adult patients with acute respiratory failure, its association with ventilatory support time, intensive care unit (ICU) length of stay (LOS), organ dysfunction and 30-day mortality.

METHODS

We included consecutive patients with acute respiratory failure during an eight-week prospective, observational multicentre study (the FINNALI-study). Acute respiratory failure was defined as a need for either non-invasive or invasive positive pressure ventilation for >6 h regardless of the underlying cause or risk factors. After informed consent, a sample for zinc measurement was drawn at 6 h after the start of treatment and analysed from 551 of these patients.

RESULTS

Low serum zinc was frequent (95.8%) at the onset acute respiratory failure. The median interquartile range [IQR] was 4.7 [3.0-6.9] μmol/l. The median [IQR] serum zinc levels in non-infectious, sepsis and septic shock patients were 5.0 [3.1-7.1], 5.1 [3.5-7.3] and 3.8 [2.6-5.9] μmol/l, respectively, P<0.01. Baseline zinc levels were not associated with ventilatory support time (P=0.98) or ICU LOS (P=0.053). The area under curve in receiver operating characteristics analysis for serum zinc regarding 30-day mortality was 0.55 (95% CI 0.49-0.60).

CONCLUSIONS

Serum zinc on initiation of ventilation had no predictive value for 30-day mortality, ventilatory support time or intensive care unit LOS.

The advent of ECMO and pumpless extracorporeal lung assist in ARDS

Despite advances in critical care facilities and ventilation therapies acute respiratory distress syndrome (ARDS) is associated with high mortality rates. The condition can stem from a multitude of causes including pneumonia, septicemia and trauma ultimately resulting in ARDS. ARDS is characterized by respiratory insufficiency with severe hypoxemia or hypercapnia. The treatment strategy depends on the knowledge of the underlying disease. But lung-protective ventilation with adjusted positive end-expiratory pressure remains the most effective therapeutic tool despite advances in prone positioning, inhalation of nitric oxide and the use of steroids. Newer modalities including extracorporeal membrane oxygenation (ECMO) and pumpless extracorporeal lung assist (PECLA) are being increasingly introduced in critical care settings as rescue therapies in patients who fail to respond to conservative measures. We describe here the introduction and advances of both ECMO and PECLA in the management of ARDS.

Partial do-not-resuscitate orders: A hazard to patient safety and clinical outcomes?

BACKGROUND

Patients and families commonly discuss end-of-life decisions with clinicians to create a treatment plan based on patient wishes. In some instances, respect for patient autonomy in making choices may create the potential for patient harm. Medical treatments are often performed in groupings in order to work effectively. When such combinations are separated as a result of patient or surrogate choices, critical elements of life- saving care may be omitted, and the patient may receive nonbeneficial or harmful treatment. A partial do-not-resuscitate order may serve as an example.

LITERATURE REVIEW AND DISCUSSION

The limited literature available regarding partial do-not-resuscitate order(s) suggests the practice is clinically and ethically problematic. Not much is known about the prevalence of these orders, but some clinicians believe they are a growing phenomenon. Medical and bioethics organizations have produced guidelines and recommendations on the use of full do-not-resuscitate order(s) with little mention of partial do-not-resuscitate order(s). Partial do-not-resuscitate order(s) are designed based on the patient's anticipated need for resuscitation and are intended to manage dying in a tolerable manner based on what the decision maker believes is "best." Through an analysis of the medical literature, we propose that a partial do-not-resuscitate order contradicts this "best" management intention because it is impossible for the decision maker, or care providers, to anticipate all possible prearrest and arrest situations. We propose that a partial do-not-resuscitate order highlights larger problems: 1) a misunderstanding of the meaning and scope of a do-not-resuscitate order and 2) a need for discussions around goals of care.

CONCLUSION

Discouraging partial do-not-resuscitate(s) order may help promote more accurate and comprehensive advance care planning.

Plasma adiponectin and mortality in critically ill subjects with acute respiratory failure

OBJECTIVE

: Adiponectin, an anti-inflammatory cytokine produced by adipose tissue, has been shown to modulate survival in animal models of critical illness. We examined the association between plasma adiponectin and clinical outcomes in critically ill patients with acute respiratory failure.

DESIGN

: Secondary analysis of a single-center, randomized controlled trial.

SETTING

: Medical intensive care unit of a university-based, tertiary medical center.

PATIENTS

: One hundred seventy-five subjects with acute respiratory failure enrolled in randomized, controlled pilot trial of Early versus Delayed Enternal Nutrition (EDEN pilot study).

INTERVENTIONS

: None.

MEASUREMENTS AND MAIN RESULTS

: Adiponectin measured within 48 hrs of respiratory failure (Apn1) was inversely correlated with body mass index (r=-0.25, p=.007) and was higher in females (median, 12.6 μg/mL; interquartile range, 7.6-17.1) than males (9.45 μg/mL; 6.2-14.2; p=.02). Adiponectin increased at day 6 (Apn1: 11.4 μg/mL [6.6-15.3] vs. Apn6: 14.1 μg/mL [10.3-18.6], p<.001). This increase was significant only in survivors (Δ adiponectin in survivors: 3.9±6 μg/mL, n=80, p<.001 vs. Δ in nonsurvivors: 1.69±4.6 μg/mL, n=14, p=.19). Higher Apn1 was significantly associated with 28-day mortality (odds ratio 1.59 per 5-μg/mL increase; 95% confidence interval 1.15-2.21; p=.006). No measured demographic, clinical, or cytokine covariates, including interleukin-6, interleukin-8, interleukin-10, interleukin-1β, interleukin-12, tumor necrosis factor-α, and interferon-γ, were confounders or effect modifiers of this association between adiponectin and mortality.

CONCLUSIONS

: Independent of measured covariates, increased plasma adiponectin levels measured within 48 hrs of respiratory failure are associated with mortality. This finding suggests that factors derived from adipose tissue play a role in modulating the response to critical illness.

The epidemiology of acute respiratory failure in hospitalized patients: a Brazilian prospective cohort study

PURPOSE

The purpose of this study was to assess risk factors associated with the development of acute respiratory failure (ARF) and death in a general intensive care unit (ICU).

MATERIALS AND METHODS

Adults who were hospitalized at 12 surgical and nonsurgical ICUs were prospectively followed up. Multivariable analyses were realized to determine the risk factors for ARF and point out the prognostic factors for mortality in these patients.

RESULTS

A total of 1732 patients were evaluated, with an ARF prevalence of 57%. Of the 889 patients who were admitted without ARF, 141 (16%) developed this syndrome in the ICU. The independent risk factors for developing ARF were 64 years of age or older, longer time between hospital and ICU admission, unscheduled surgical or clinical reason for ICU admission, and severity of illness. Of the 984 patients with ARF, 475 (48%) died during the ICU stay. Independent prognostic factors for death were age older than 64 years, time between hospital and ICU admission of more than 4 days, history of hematologic malignancy or AIDS, the development of ARF in ICU, acute lung injury, and severity of illness.

CONCLUSIONS

Acute respiratory failure represents a large percentage of all ICU patients, and the high mortality is related to some preventable factors such as the time to ICU admission.

Effect of oral β-blocker on short and long-term mortality in patients with acute respiratory failure: results from the BASEL-II-ICU study

INTRODUCTION

Acute respiratory failure (ARF) is responsible for about one-third of intensive care unit (ICU) admissions and is associated with adverse outcomes. Predictors of short- and long-term outcomes in unselected ICU-patients with ARF are ill-defined. The purpose of this analysis was to determine predictors of in-hospital and one-year mortality and assess the effects of oral beta-blockers in unselected ICU patients with ARF included in the BASEL-II-ICU study.

METHODS

The BASEL II-ICU study was a prospective, multicenter, randomized, single-blinded, controlled trial of 314 (mean age 70 (62 to 79) years) ICU patients with ARF evaluating impact of a B-type natriuretic peptide- (BNP) guided management strategy on short-term outcomes.

RESULTS

In-hospital mortality was 16% (51 patients) and one-year mortality 41% (128 patients). Multivariate analysis assessed that oral beta-blockers at admission were associated with a lower risk of both in-hospital (HR 0.33 (0.14 to 0.74) P = 0.007) and one-year mortality (HR 0.29 (0.16 to 0.51) P = 0.0003). Kaplan-Meier analysis confirmed the lower mortality in ARF patients when admitted with oral beta-blocker and further shows that the beneficial effect of oral beta-blockers at admission holds true in the two subgroups of patients with ARF related to cardiac or non-cardiac causes. Kaplan-Meier analysis also shows that administration of oral beta-blockers before hospital discharge gives striking additional beneficial effects on one-year mortality.

CONCLUSIONS

Established beta-blocker therapy appears to be associated with a reduced mortality in ICU patients with acute respiratory failure. Cessation of established therapy appears to be hazardous. Initiation of therapy prior to discharge appears to confer benefit. This finding was seen regardless of the cardiac or non-cardiac etiology of respiratory failure.

TRIAL REGISTRATION

clinicalTrials.gov Identifier: NCT00130559.

Significance of elevated cardiac troponin T levels in critically ill patients with acute respiratory disease

BACKGROUND

Elevations in cardiac troponin have prognostic importance in critically ill patients. However, there are no data addressing the independent association between troponin levels and mortality, adjusted for the severity of the underlying disease, in patients hospitalized for acute respiratory disorders. We investigated whether troponin T (cTnT) elevations are independently associated with in-hospital mortality in patients in the intensive care unit (ICU) admitted for severe and acute respiratory conditions. After adjusting for the severity of disease measured by the Acute Physiology, Age, and Chronic Health Evaluation (APACHE) III prognostic system, we evaluated short-term (30 days) and long-term (3 years) mortality.

METHODS

We studied the APACHE III database and cTnT levels from patients admitted consecutively to the ICU at Mayo Clinic, Rochester, Minnesota. Between January 2001 and December 2005, 2078 patients with respiratory conditions had cTnT measured at ICU admission. In-hospital, short-term (30 days) and long-term (3 years) all-cause mortality were determined.

RESULTS

Of the study patients, 878 (42.3%) had elevated cTnT and 1200 patients (57.7%) had undetectable cTnT. During hospitalization, 1.1% of the patients with troponin T <0.01 ng/mL died compared to 21% of those with troponin T ≥0.01 ng/mL (P <.0001). At 30 days, mortality was 18.6% in patients with elevations of cTnT and 1.5% in patients without elevations of cTnT (P <.0001). The Kaplan-Meier probability of survival at 1-year follow-up was 71.0%, at 2-year follow-up was 48.3%, and 3-year follow-up was 39.4% with troponin T ≥0.01 ng/mL and at 1-year follow-up was 98.8%, at 2-year follow-up was 97.2%, and at 3-year follow-up was 95.5% with troponin T <0.01 μg/L (P <.0001). After adjustment for severity of disease and baseline characteristics, cTnT levels remained associated with in-hospital, short-term and long-term mortality (P <.0001).

CONCLUSIONS

In patients admitted to the ICU for respiratory disorders, cTnT elevations are independently associated with in-hospital, short-term and long-term mortality.

The neuronal guidance protein netrin-1 reduces alveolar inflammation in a porcine model of acute lung injury

Introduction

Acute lung injury (ALI) is an inflammatory disorder of pulmonary or extrapulmonary origin. We have previously demonstrated that netrin-1 dampens murine ALI, and in an attempt to advance this finding into future clinical practice we evaluated whether netrin-1 would reduce alveolar inflammation during porcine ALI.

Methods

This was a controlled in vivo experimental study in pigs. We induced ALI through lipoploysaccharide (LPS) infusion (50 μg/kg) for 2 hours. Following this, we exposed animals to either vehicle, intravenous netrin-1 (netrin-1 i.v.) or inhaled netrin-1 (netrin-1 inh.). Serum samples and bronchoalveolar lavage (BAL) were obtained to determine levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, interleukin-6 and interleukin-8 at baseline and 6 hours following treatment. Myeloperoxidase activity (MPO) and protein levels were determined in the BAL, and tissue samples were obtained for histological evaluation. Finally, animals were scanned with spiral CT.

Results

Following LPS infusion, animals developed acute pulmonary injury. Serum levels of TNF-α and IL-6 were significantly reduced in the netrin-1 i.v. group. BAL demonstrated significantly reduced cytokine levels 6 hours post-netrin-1 treatment (TNF-α: vehicle 633 ± 172 pg/ml, netrin-1 i.v. 84 ± 5 pg/ml, netrin-1 inh. 168 ± 74 pg/ml; both P < 0.05). MPO activity and protein content were significantly reduced in BAL samples from netrin-1-treated animals. Histological sections confirmed reduced inflammatory changes in the netrin-1-treated animals. Computed tomography corroborated reduced pulmonary damage in both netrin-1-treated groups.

Conclusions

We conclude that treatment with the endogenous anti-inflammatory protein netrin-1 reduces pulmonary inflammation during the initial stages of ALI and should be pursued as a future therapeutic option.

Critical care and the global burden of critical illness in adults

Critical care has evolved from treatment of poliomyelitis victims with respiratory failure in an intensive care unit to treatment of severely ill patients irrespective of location or specific technology. Population-based studies in the developed world suggest that the burden of critical illness is higher than generally appreciated and will increase as the population ages. Critical care capacity has long been needed in the developing world, and efforts to improve the care of the critically ill in these settings are starting to occur. Expansion of critical care to handle the consequences of an ageing population, natural disasters, conflict, inadequate primary care, and higher-risk medical therapies will be challenged by high costs at a time of economic constraint. To meet this challenge, investigators in this discipline will need to measure the global burden of critical illness and available critical-care resources, and develop both preventive and therapeutic interventions that are generalisable across countries.

Early predictors of morbidity and mortality in trauma patients treated in the intensive care unit

BACKGROUND

We investigated the incidence and severity of post-injury morbidity and mortality in intensive care unit (ICU)-treated trauma patients. We also identified risk factors in the early phase after injury that predicted the later development of complications.

METHODS

A prospective observational cohort study design was used. One hundred and sixty-four adult patients admitted to the ICU for more than 24 h were included during a 21-month period. The incidence and severity of morbidity such as multiple organ failure (MOF), acute lung injury (ALI), severe sepsis and 30-day post-injury mortality were calculated and risk factors were analyzed with uni- and multivariable logistic regression analysis.

RESULTS

The median age was 40 years, the injury severity score was 24, the new injury severity score was 29, the acute physiology and chronic health evaluation II score was 15, sequential organ failure assessment maximum was 7 and ICU length of stay was 3.1 days. The incidences of post-injury MOF were 40.2%, ALI 25.6%, severe sepsis 31.1% and 30-day mortality 10.4%. The independent risk factors differed to some extent between the outcome parameters. Age, severity of injury, significant head injury and massive transfusion were independent risk factors for several outcome parameters. Positive blood alcohol was only a predictor of MOF, whereas prolonged rescue time only predicted death. Unexpectedly, injury severity was not an independent risk factor for mortality.

CONCLUSIONS

Although the incidence of morbidity was considerable, mortality was relatively low. Early post-injury risk factors that predicted later development of complications differed between morbidity and mortality.

Eight-year trend of acute respiratory distress syndrome: a population-based study in Olmsted County, Minnesota

RATIONALE

significant progress has been made in understanding the pathogenesis of acute respiratory distress syndrome (ARDS). Recent advances in hospital practice may have reduced the incidence of this lethal syndrome.

OBJECTIVES

to observe incidence trends and associated outcomes of ARDS.

METHODS

this population-based cohort study was conducted in Olmsted County, Minnesota. Using a validated screening protocol, investigators identified intensive care patients with acute hypoxemia and bilateral pulmonary infiltrates. The presence of ARDS was independently confirmed according to American-European Consensus Conference criteria. The incidence of ARDS and associated outcomes were compared over the 8-year study period (2001-2008).

MEASUREMENTS AND MAIN RESULTS

over the 8-year period, critically ill Olmsted County residents presented with increasing severity of acute illness, a greater number of comorbidities, and a higher prevalence of major predisposing conditions for ARDS. The ARDS incidence decreased significantly from 82.4 to 38.9 per 100,000 person-years during the study period (P < 0.001). A decline in hospital-acquired ARDS (P < 0.001) was responsible for the fall in the incidence density with no change on admission (P = 0.877). Overall, mortality and hospital and intensive care unit lengths of stay decreased over time (P < 0.001), whereas the ARDS case-fatality did not change significantly.

CONCLUSIONS

despite an increase in patients' severity of illness, number of comorbidities, and prevalence of major ARDS risk factors, the incidence of ARDS in this suburban community decreased by more than half. Correlation of the observed findings with changes in health care delivery may have important implications for the planning of acute care services in other regions.

Aerosolized prostacyclin for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS)

BACKGROUND

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are critical conditions that are associated with high mortality and morbidity. Aerosolized prostacyclin has been used to improve oxygenation despite the limited evidence available so far.

OBJECTIVES

To systematically assess the benefits and harms of aerosolized prostacyclin in critically ill patients with ALI and ARDS.

SEARCH STRATEGY

We identified randomized clinical trials (RCTs) from electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 1); MEDLINE; EMBASE; Science Citation Index Expanded; International Web of Science; CINAHL; LILACS; and the Chinese Biomedical Literature Database (to 31st January 2010). We contacted trial authors and manufacturers in the field.

SELECTION CRITERIA

We included all RCTs, irrespective of blinding or language, that compared aerosolized prostacyclin with no intervention or placebo in either children or adults with ALI or ARDS.

DATA COLLECTION AND ANALYSIS

Two authors independently abstracted data and resolved any disagreements by discussion. We presented pooled estimates of the intervention effects as relative risks (RR) with 95% confidence intervals (CI) for dichotomous outcomes. Our primary outcome measure was all cause mortality. We planned to perform subgroup and sensitivity analyses to assess the effect of aerosolized prostacyclin in adults and children, and on various clinical and physiological outcomes. We assessed the risk of bias through assessment of methodological trial components and the risk of random error through trial sequential analysis.

MAIN RESULTS

We included one paediatric RCT with low risk of bias and involving a total of 14 critically ill children with ALI or ARDS. Aersosolized prostacyclin over less than 24 hours did not reduce overall mortality at 28 days (RR 1.50, 95% CI 0.17 to 12.94) compared with aerosolized saline (a total of three deaths). The authors did not encounter any adverse events such as bleeding or organ dysfunction. We were unable to perform the prespecified subgroups and sensitivity analyses or trial sequential analysis due to the limited number of RCTs. We were also not able to assess the safety and efficacy of aerosolized prostacyclin for ALI and ARDS. We found two ongoing trials, one involving adults and the other paediatric participants. The adult trial has been finalized but the data are not yet available.

AUTHORS' CONCLUSIONS

There is no current evidence to support or refute the routine use of aerosolized prostacyclin for patients with ALI and ARDS. There is an urgent need for more randomized clinical trials.

Bedside quantification of dead-space fraction using routine clinical data in patients with acute lung injury: secondary analysis of two prospective trials

INTRODUCTION

Dead-space fraction (Vd/Vt) has been shown to be a powerful predictor of mortality in acute lung injury (ALI) patients. The measurement of Vd/Vt is based on the analysis of expired CO2 which is not a part of standard practice thus limiting widespread clinical application of this method. The objective of this study was to determine prognostic value of Vd/Vt estimated from routinely collected pulmonary variables.

METHODS

Secondary analysis of the original data from two prospective studies of ALI patients. Estimated Vd/Vt was calculated using the rearranged alveolar gas equation: Vd/Vt=1-[(0.86×VCO2est)/(VE×PaCO2)] where VCO2est is the estimated CO2 production calculated from the Harris Benedict equation, minute ventilation (VE) is obtained from the ventilator rate and expired tidal volume and PaCO2 from arterial gas analysis. Logistic regression models were created to determine the prognostic value of estimated Vd/Vt.

RESULTS

One hundred and nine patients in Mayo Clinic validation cohort and 1896 patients in ARDS-net cohort demonstrated an increase in percent mortality for every 10% increase in Vd/Vt in a dose response fashion. After adjustment for non-pulmonary and pulmonary prognostic variables, both day 1 (adjusted odds ratio-OR = 1.07, 95%CI 1.03 to 1.13) and day 3 (OR = 1.12, 95% CI 1.06 to 1.18) estimated dead-space fraction predicted hospital mortality.

CONCLUSIONS

Elevated estimated Vd/Vt predicts mortality in ALI patients in a dose response manner. A modified alveolar gas equation may be of clinical value for a rapid bedside estimation of Vd/Vt, utilizing routinely collected clinical data.

Noninvasive positive pressure ventilation for patients with acute hypoxemic respiratory failure?

The re-emergence of noninvasive positive pressure ventilation (NIV) represents perhaps the single greatest advance in mechanical ventilation over the last 20 years. Clear benefit has been demonstrated for patients with respiratory failure in the setting of acute exacerbations of chronic obstructive pulmonary disease and cardiogenic pulmonary edema. While there are advocates for the use of NIV in patients presenting with acute hypoxemic respiratory failure not due to cardiogenic pulmonary edema, benefit for these patients is less clear. This article reviews briefly the heterogeneity of hypoxemic respiratory failure and looks at the current evidence to support NIV in this setting in some depth. Presently, there is little evidence to support the use of NIV for patients presenting with hypoxemic respiratory failure who fulfill the American and European Consensus Conference definition of acute lung injury or acute respiratory distress syndrome, other than in patients with high risk for death if endotracheally intubated (immunocompromised patients, postlung resection acute respiratory distress syndrome). As there are reasonable rationales for both benefit and harm, there is a need for a large, multicenter, randomized, controlled trial to clarify whether NIV offers benefit in terms of a reduced need for endotracheal intubation, length of stay and hospital mortality.

Inhaled nitric oxide for acute respiratory distress syndrome (ARDS) and acute lung injury in children and adults

BACKGROUND

Acute hypoxaemic respiratory failure (AHRF), defined as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), are critical conditions. AHRF results from a number of systemic conditions and is associated with high mortality and morbidity in all ages. Inhaled nitric oxide (INO) has been used to improve oxygenation but its role remains controversial.

OBJECTIVES

To systematically assess the benefits and harms of INO in critically ill patients with AHRF.

SEARCH STRATEGY

Randomized clinical trials (RCTs) were identified from electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 1); MEDLINE; EMBASE; Science Citation Index Expanded; International Web of Science; CINAHL; LILACS; and the Chinese Biomedical Literature Database (up to 31st January 2010). We contacted trial authors, authors of previous reviews, and manufacturers in the field.

SELECTION CRITERIA

We included all RCTs, irrespective of blinding or language, that compared INO with no intervention or placebo in children or adults with AHRF.

DATA COLLECTION AND ANALYSIS

Two authors independently abstracted data and resolved any disagreements by discussion. We presented pooled estimates of the intervention effects on dichotomous outcomes as relative risks (RR) with 95% confidence intervals (CI). Our primary outcome measure was all cause mortality. We performed subgroup and sensitivity analyses to assess the effect of INO in adults and children and on various clinical and physiological outcomes. We assessed the risk of bias through assessment of trial methodological components and the risk of random error through trial sequential analysis.

MAIN RESULTS

We included 14 RCTs with a total of 1303 participants; 10 of these trials had a high risk of bias. INO showed no statistically significant effect on overall mortality (40.2% versus 38.6%) (RR 1.06, 95% CI 0.93 to 1.22; I(2) = 0) and in several subgroup and sensitivity analyses, indicating robust results. Limited data demonstrated a statistically insignificant effect of INO on duration of ventilation, ventilator-free days, and length of stay in the intensive care unit and hospital. We found a statistically significant but transient improvement in oxygenation in the first 24 hours, expressed as the ratio of partial pressure of oxygen to fraction of inspired oxygen and the oxygenation index (MD 15.91, 95% CI 8.25 to 23.56; I(2) = 25%). However, INO appears to increase the risk of renal impairment among adults (RR 1.59, 95% CI 1.17 to 2.16; I(2) = 0) but not the risk of bleeding or methaemoglobin or nitrogen dioxide formation.

AUTHORS' CONCLUSIONS

INO cannot be recommended for patients with AHRF. INO results in a transient improvement in oxygenation but does not reduce mortality and may be harmful.

Severe hypoxemic respiratory failure: part 1--ventilatory strategies

Approximately 16% of deaths in patients with ARDS results from refractory hypoxemia, which is the inability to achieve adequate arterial oxygenation despite high levels of inspired oxygen or the development of barotrauma. A number of ventilator-focused rescue therapies that can be used when conventional mechanical ventilation does not achieve a specific target level of oxygenation are discussed. A literature search was conducted and narrative review written to summarize the use of high levels of positive end-expiratory pressure, recruitment maneuvers, airway pressure-release ventilation, and high-frequency ventilation. Each therapy reviewed has been reported to improve oxygenation in patients with ARDS. However, none of them have been shown to improve survival when studied in heterogeneous populations of patients with ARDS. Moreover, none of the therapies has been reported to be superior to another for the goal of improving oxygenation. The goal of improving oxygenation must always be balanced against the risk of further lung injury. The optimal time to initiate rescue therapies, if needed, is within 96 h of the onset of ARDS, a time when alveolar recruitment potential is the greatest. A variety of ventilatory approaches are available to improve oxygenation in the setting of refractory hypoxemia and ARDS. Which, if any, of these approaches should be used is often determined by the availability of equipment and clinician bias.

Acute lung injury and ARDS in acute pancreatitis: Mechanisms and potential intervention

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in acute pancreatitis still represents a substantial problem, with a mortality rate in the range of 30%-40%. The present review evaluates underlying pathophysiological mechanisms in both ALI and ARDS and potential clinical implications. Several mediators and pathophysiological pathways are involved during the different phases of ALI and ARDS. The initial exudative phase is characterized by diffuse alveolar damage, microvascular injury and influx of inflammatory cells. This phase is followed by a fibro-proliferative phase with lung repair, type II pneumocyte hypoplasia and proliferation of fibroblasts. Proteases derived from polymorphonuclear neutrophils, various pro-inflammatory mediators, and phospholipases are all involved, among others. Contributing factors that promote pancreatitis-associated ALI may be found in the gut and mesenteric lymphatics. There is a lack of complete understanding of the underlying mechanisms, and by improving our knowledge, novel tools for prevention and intervention may be developed, thus contributing to improved outcome.

Use of intensive care, mechanical ventilation, both, or neither by patients with acute lung injury

OBJECTIVE

Reports of acute lung injury and acute respiratory distress syndrome have generally been restricted to mechanically ventilated intensive care unit patients, creating an incomplete picture of the epidemiologies of the syndromes. We sought to determine the incidence and outcomes of acute lung injury and acute respiratory distress syndromes throughout an entire hospital population.

DESIGN

Retrospective cohort study.

SETTING

A Department of Veterans Affairs medical center.

PATIENTS

All patients satisfying criteria for acute lung injury or acute respiratory distress syndrome during a 2-yr period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 11,465 acute medical and surgical admissions during the study period; 156 patients had acute lung injury or acute respiratory distress syndrome. Only 74 (47%) were invasively ventilated in an intensive care unit for acute lung injury. Another 15 (10%) patients were ventilated for other reasons, 41 (26%) were admitted to an intensive care unit at approximately the time of acute lung injury onset but were not invasively ventilated, and 26 (17%) were managed with neither invasive ventilation nor admission to an intensive care unit. Four-week mortality differed by group (p = .023), ranging from 22% among those managed in an intensive care unit without invasive ventilation to 50% among those ventilated for acute lung injury or acute respiratory distress syndrome. By 2 yrs, differences in survival between groups were no longer significant. Notably, only 53 (34%) patients would have been eligible for widely cited acute lung injury intervention trials. Ten patients had a second episode of acute lung injury during the study period, equating to a 16%-per-year risk of recurrence.

CONCLUSIONS

Acute lung injury and acute respiratory distress syndrome studies restricted to patients mechanically ventilated in intensive care units substantially underestimate the incidence of the syndromes. Nonventilated patients and those cared for outside of intensive care units may still be at substantial risk for death. Further characterization of previously overlooked acute lung injury and acute respiratory distress syndrome patients may suggest new therapeutic opportunities.

Acute respiratory failure in the patient with cancer: diagnostic and management strategies

Acute respiratory failure (ARF) remains the major reason for admission to the intensive care unit (ICU) in patients with cancer and is often associated with high mortality, especially in those who require mechanical ventilation. The diagnosis and management of ARF in patients who have cancer pose unique challenges to the intensivist. This article reviews the most common causes of ARF in patients with cancer and discusses recent advances in the diagnostic and management approaches of these disorders. Timely diagnosis and treatment of reversible causes of respiratory failure, including earlier use of noninvasive ventilation and judicious ventilator and fluid management in patients with acute lung injury, are essential to achieve an optimal outcome. Close collaboration between oncologists and intensivists helps ensure that clear goals, including direction of treatment and quality of life, are established for every patient with cancer who requires mechanical ventilation for ARF.

Beyond mortality: future clinical research in acute lung injury

Mortality in National Heart, Lung and Blood Institute-sponsored clinical trials of treatments for acute lung injury (ALI) has decreased dramatically during the past two decades. As a consequence, design of such trials based on a mortality outcome requires ever-increasing numbers of patients. Recognizing that advances in clinical trial design might be applicable to these trials and might allow trials with fewer patients, the National Heart, Lung and Blood Institute convened a workshop of extramural experts from several disciplines. The workshop assessed the current state of clinical research addressing ALI, identified research needs, and recommended: (1) continued performance of trials evaluating treatments of patients with ALI; (2) development of strategies to perform ALI prevention trials; (3) observational studies of patients without ALI undergoing prolonged mechanical ventilation; and (4) development of a standardized format for reporting methods, endpoints, and results of ALI trials.

[Acute respiratory failure concomitant with serious disease or injury]

BACKGROUND

Acute respiratory failure has an annual incidence of 20-75/100,000 and is the most common reason for admittance to an intensive care unit. A common cause is acute inflammatory changes in lung tissue. The article reviews clinical, etiological, pathophysiological and therapeutic aspects of acute respiratory failure, with an emphasis on failure secondary to proinflammatory processes.

MATERIAL AND METHODS

This paper is not based on a comprehensive literature review, but on the clinical and scientific experience of the author, literature from a private archive and a limited Medline search.

RESULTS

Acute respiratory failure can be precipitated by agents and/or trauma that damage the lungs directly. Serious infections and tissue damage located in other parts of the body can also cause respiratory failure. In these cases, the blood transports activated blood cells and proinflammatory agents to the lungs where they induce secondary tissue inflammation. The resulting respiratory failure is often serious. Mortality is in the range 30-50 %.

INTERPRETATION

No specific treatment is available for secondary tissue inflammation; it usually resolves when the precipitating injuries or disease processes are healed. Positive pressure ventilation can prevent serious hypoxemia from causing additional damage to affected tissue. With modern treatment in an intensive care unit only 10-15 % of the deaths are caused by the respiratory failure per se, most deaths are caused by failure of several additional organs (multiorgan failure).

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.

Predictors of in-hospital mortality among hospitalized nursing home residents: an analysis of the National Hospital Discharge Surveys 2005-2006

OBJECTIVE

To determine the demographic and clinical predictors of in-hospital mortality among hospitalized nursing home (NH) residents.

DESIGN

Retrospective analysis of the public-use copies of the 2005-2006 National Hospital Discharge Survey (NHDS) datasets.

SETTING

Non-federal acute-care, short-stay hospitals in all 50 states and the District of Columbia.

PARTICIPANTS

Participants were 1904 and 1752 NH residents, 45 years or older, hospitalized in 2005 and 2006, respectively.

MEASUREMENTS

In-hospital mortality.

METHODS

A multivariable logistic regression model was developed to determine independent predictors of in-hospital mortality using the 2005 dataset. The model was then applied to the 2006 dataset to determine the generalizability of the predictors.

RESULTS

Significant independent predictors of in-hospital mortality in 2005 included age 85 years or older (adjusted odds ratio [OR], 2.53; 95% confidence interval [CI], 1.21-5.30; P=.013), acute respiratory failure (adjusted OR, 5.67; 95% CI, 3.51-9.17; P < .0001), septicemia (adjusted OR, 4.63; 95% CI, 3.08-6.96; P < .0001), and acute renal failure (adjusted OR, 2.11; 95% CI, 1.30-3.41; P=.002). The following baseline characteristics also predicted in-hospital mortality in 2006: age 85 years or older (adjusted OR, 2.45; 95% CI, 1.31-4.59; P=.005), acute respiratory failure (adjusted OR, 7.11; 95% CI, 4.46-11.33; P < .0001), septicemia (adjusted OR, 3.91; 95% CI, 2.64-5.80; P < .0001), and acute renal failure (adjusted OR, 2.75; 95% CI, 1.82-4.15; P < .0001). Chronic morbidities were not associated with in-hospital mortality.

CONCLUSION

Among hospitalized NH residents, age 85 years or older and several acute conditions, but not chronic morbidities, predicted in-hospital mortality. Elderly NH residents at risk of developing these acute conditions may benefit from palliative care.

Age, invasive ventilatory support and outcomes in elderly patients admitted to intensive care units

BACKGROUND

although advancing age is associated with worse outcomes on mechanically ventilated elderly patients admitted to intensive care units (ICU), this relation has not been extensively investigated on patients not requiring invasive ventilatory support.

OBJECTIVE

to determine the relationship between age and in-hospital mortality of elderly patients, admitted to ICU, requiring and not requiring invasive ventilatory support.

DESIGN

prospective observational cohort study conducted over a period of 11 months.

SETTING

medical-surgical ICU at a Brazilian university hospital.

SUBJECTS

a total of 840 patients aged 55 years and older were admitted to ICU.

METHODS

in-hospital death rates for patients requiring and not requiring invasive ventilatory support were compared across three successive age intervals (55-64; 65-74 and 75 or more years), adjusting for severity of illness using the Acute Physiologic Score.

RESULTS

age was strongly correlated with mortality among the invasively ventilated subgroup of patients and the multivariate adjusted odds ratios increased progressively with every age increment (OR = 1.60, 95% CI = 1.01-2.54 for 65-74 years old and OR = 2.68, 95% CI = 1.58-4.56 for > or =75 years). For the patients not submitted to invasive ventilatory support, age was not independently associated with in-hospital mortality (OR = 2.28, 95% CI = 0.99-5.25 for 65-74 years old and OR = 1.95, 95% CI = 0.82-4.62 for > or =75 years old).

CONCLUSIONS

the combination of age and invasive mechanical ventilation is strongly associated with in-hospital mortality. Age should not be considered as a factor related to in-hospital mortality of elderly patients not requiring invasive ventilatory support in ICU.

Inflammation-associated repression of vasodilator-stimulated phosphoprotein (VASP) reduces alveolar-capillary barrier function during acute lung injury

Acute lung injury (ALI) is an inflammatory disorder associated with reduced alveolar-capillary barrier function, increased pulmonary vascular permeability, and infiltration of leukocytes into the alveolar space. Pulmonary function might be compromised, its most severe form being the acute respiratory distress syndrome. A protein central to physiological barrier properties is vasodilator-stimulated phosphoprotein (VASP). Given the fact that VASP expression is reduced during periods of cellular hypoxia, we investigated the role of VASP during ALI. Initial studies revealed reduced VASP expressional levels through cytokines in vitro. Studies in the putative human VASP promoter identified NF-kappaB as a key regulator of VASP transcription. This VASP repression results in increased paracellular permeability and migration of neutrophils in vitro. In a model of LPS-induced ALI, VASP(-/-) mice demonstrated increased pulmonary damage compared with wild-type animals. These findings were confirmed in a second model of ventilator-induced lung injury. Studies employing bone marrow chimeric animals identified tissue-specific repression of VASP as the underlying cause of decreased barrier properties of the alveolar-capillary barrier during ALI. Taken together these studies identify tissue-specific VASP as a central protein in the control of the alveolar-capillary barrier properties during ALI.

A minimal model of lung mechanics and model-based markers for optimizing ventilator treatment in ARDS patients

A majority of patients admitted to the Intensive Care Unit (ICU) require some form of respiratory support. In the case of Acute Respiratory Distress Syndrome (ARDS), the patient often requires full intervention from a mechanical ventilator. ARDS is also associated with mortality rate as high as 70%. Despite many recent studies on ventilator treatment of the disease, there are no well established methods to determine the optimal Positive End-Expiratory Pressure (PEEP) or other critical ventilator settings for individual patients. A model of fundamental lung mechanics is developed based on capturing the recruitment status of lung units. The main objective of this research is to develop a minimal model that is clinically effective in determining PEEP. The model was identified for a variety of different ventilator settings using clinical data. The fitting error was between 0.1% and 4% over the inflation limb and between 0.3% and 13% over the deflation limb at different PEEP settings. The model produces good correlation with clinical data, and is clinically applicable due to the minimal number of patient specific parameters to identify. The ability to use this identified patient specific model to optimize ventilator management is demonstrated by its ability to predict the patient specific response of PEEP changes before clinically applying them. Predictions of recruited lung volume change with change in PEEP have a median absolute error of 1.87% (IQR: 0.93-4.80%; 90% CI: 0.16-11.98%) for inflation and a median of 5.76% (IQR: 2.71-10.50%; 90% CI: 0.43-17.04%) for deflation, across all data sets and PEEP values (N=34predictions). This minimal model thus provides a clinically useful and relatively simple platform for continuous patient specific monitoring of lung unit recruitment for a patient.

Acute respiratory failure in intensive care units. FINNALI: a prospective cohort study

OBJECTIVE

To evaluate the incidence, treatment and mortality of acute respiratory failure (ARF) in Finnish intensive care units (ICUs).

STUDY DESIGN

Prospective multicentre cohort study.

METHODS

All adult patients in 25 ICUs were screened for use of invasive or non-invasive ventilatory support during an 8-week period. Patients needing ventilatory support for more than 6 h were included and defined as ARF patients. Risk factors for ARF and details of prior chronic health status were assessed. Ventilatory and concomitant treatments were evaluated and recorded daily throughout the ICU stay. ICU and 90-day mortalities were assessed.

RESULTS

A total of 958 (39%) from the 2,473 admitted patients were treated with ventilatory support for more than 6 h. Incidence of ARF, acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) was 149.5, 10.6 and 5.0/100,000 per year, respectively. Ventilatory support was started with non-invasive interfaces in 183 of 958 (19%) patients. Ventilatory modes allowing triggering of spontaneous breaths were preferred (81%). Median tidal volume/predicted body weight was 8.7 (7.6-9.9) ml/kg and plateau pressure 19 (16-23) cmH2O. The 90-day mortality of ARF was 31%.

CONCLUSIONS

While the incidence of ARF requiring ventilatory support is higher, the incidence of ALI and ARDS seems to be lower in Finland than previously reported in other countries. Tidal volumes are higher than recommended in the concept of lung protective strategy. However, restriction of peak airway pressure was used in the majority of ARF patients.

A national survey on the practice and outcomes of mechanical ventilation in Korean intensive care units

A study was undertaken to describe the practice and outcomes of mechanical ventilation throughout Korea. This prospective cohort study was conducted over a three-month period enrolling patients (n = 519) who received mechanical ventilation for more than 72 hours in 21 university hospital intensive care units throughout Korea. The most common indication for mechanical ventilation was acute respiratory failure. The most common cause of acute-on-chronic respiratory failure was tuberculous lung disease. The most common initial mode for ventilation was volume-controlled ventilation. The mean tidal volume of acute respiratory distress syndrome patients was 7.6 ml/kg of the predicted body weight and the mean positive end-expiratory pressure was 9.4 cmH20. The weaning success rate at 28 days was 50.3%. Pressure support and the T-piece were most commonly used as initial and final weaning modes respectively. Preventive measures against deep vein thrombosis during mechanical ventilation were performed more frequently in intensive care units with full-time critical care physicians than those without such physicians. Multivariate analysis showed that the APACHE II score, indication for mechanical ventilation, respiratory rate at 72 hours, enteral feeding and prophylaxis of deep vein thrombosis were prognostic factors for survival. In Korean intensive care units, tuberculous lung disease remains an important cause for mechanical ventilation. The practice of mechanical ventilation in Korean intensive care units in general appeared to comply with the current international recommendations with regard to lung protection and weaning. However, intensive care units lacking critical care physicians seemed to be adopting fewer ancillary measures, such as deep vein thrombosis prophylaxis.

Mechanical ventilation: epidemiological insights into current practices

PURPOSE OF REVIEW

To describe the trends in the results of epidemiological studies of mechanical ventilation.

RECENT FINDINGS

Changes in population demographics have increased the incidence of mechanical ventilation. Higher age and comorbidity rates portend poorer outcomes of mechanical ventilation. The most common indication for initiation of mechanical ventilation is acute respiratory failure, including postoperative respiratory failure, pneumonia, sepsis, and acute respiratory distress syndrome. Patients with sepsis and acute respiratory distress syndrome have a much higher mortality risk than the rest of this population. Changes over time in the selection of modes of ventilation, tidal volumes, positive end-expiratory pressure levels, weaning strategies, and tracheostomy timing appear to accord with data from randomized controlled trials in the literature. However, despite these changes, observational studies have not detected a statistically significant change in adjusted mortality over time.

SUMMARY

The burden of critical illness will likely continue to increase in the future. Evidence from randomized trials appears to have affected the management of mechanical ventilation, but adherence to evidence-based practices may not be ideal.