Heart rate reduction with esmolol is associated with improved arterial elastance in patients with septic shock: a prospective observational study.

PURPOSE: Ventricular-arterial (V-A) decoupling decreases myocardial efficiency and is exacerbated by tachycardia that increases static arterial elastance (Ea). We thus investigated the effects of heart rate (HR) reduction on Ea in septic shock patients using the beta-blocker esmolol. We hypothesized that esmolol improves Ea by positively affecting the tone of arterial vessels and their responsiveness to HR-related changes in stroke volume (SV). METHODS: After at least 24 h of hemodynamic optimization, 45 septic shock patients, with an HR ≥95 bpm and requiring norepinephrine to maintain mean arterial pressure (MAP) ≥65 mmHg, received a titrated esmolol infusion to maintain HR between 80 and 94 bpm. Ea was calculated as MAP/SV. All measurements, including data from right heart catheterization, echocardiography, arterial waveform analysis, and norepinephrine requirements, were obtained at baseline and at 4 h after commencing esmolol. RESULTS: Esmolol reduced HR in all patients and this was associated with a decrease in Ea (2.19 ± 0.77 vs. 1.72 ± 0.52 mmHg l(-1)), arterial dP/dt max (1.08 ± 0.32 vs. 0.89 ± 0.29 mmHg ms(-1)), and a parallel increase in SV (48 ± 14 vs. 59 ± 18 ml), all p < 0.05. Cardiac output and ejection fraction remained unchanged, whereas norepinephrine requirements were reduced (0.7 ± 0.7 to 0.58 ± 0.5 µg kg(-1) min(-1), p < 0.05). CONCLUSIONS: HR reduction with esmolol effectively improved Ea while allowing adequate systemic perfusion in patients with severe septic shock who remained tachycardic despite standard volume resuscitation. As Ea is a major determinant of V-A coupling, its reduction may contribute to improving cardiovascular efficiency in septic shock.

Non-invasive ventilation in patients with hematologic malignancy: a new prospective.

Immunosuppressed patients are usually considered together without distinction. However, patients with hematologic malignancy should be included in a different subcategory. The outcome of this population has improved over the years. However, mortality rate continues to be high, especially when respiratory complications are present and mechanical ventilation is required. Non-invasive ventilation (NIV) demonstrated its efficacy on the process of respiratory failure improving clinical outcomes in patients of different diagnoses. Recommendations of guidelines to use NIV in immunosuppressed patients have been quite prudent. However, NIV has been recently applied in hematologic malignancy patients during an early or/and late respiratory failure, showing a favorable impact improving the outcome. At an early stage, one study showed CPAP to reduce respiratory complications and to improve the outcome of mortality rate from 75% in the control group to 15% in the treatment group, when compared to oxygen therapy. In other two randomized control trials, NIV in comparison to invasive mechanical ventilation demonstrated to reduce mortality rate from 100% to 53-61%. As most of the non-randomized control trials applied NIV in a general population of immunosuppressed patients, results are very difficult to analyze. So far, the treatment starting, and duration time are still not clearly defined. Novel clinical trials should be performed to elucidate the appropriate application of NIV in this population.

Respiratory failure due to upper airway obstruction in children: use of the helmet as bridge interface.

Upper airway obstruction (UAO) can cause severe respiratory distress in young children by increasing inspiratory muscle load and decreasing alveolar ventilation, ultimately resulting in hypercapnia and hypoxemia which have long term negative cardiovascular effects. Although non-invasive continuous positive airway pressure (CPAP) improves gas exchange in these patients, use of conventional interfaces (nasal mask, nasal pillow and facial mask) may cause significant discomfort and lead to CPAP intolerance. We report five cases of children affected by UAO who experienced CPAP intolerance via application of conventional interfaces. Alternatively, we acutely applied helmet-CPAP which resulted in improved breathing pattern and gas exchange. Thereafter, patients received training with respect to a nasal CPAP interface, allowing successful long term treatment. In conclusion, these five clinical cases demonstrate that helmet-CPAP can be used acutely in children with UAO if compliance to conventional modalities is problematic, allowing for sufficient time to achieve compliance to nasal-CPAP.

Epidemiology and outcome of sepsis syndromes in Italian ICUs: a muticentre, observational cohort study in the region of Piedmont.

BACKGROUND: Sepsis is an important cause of mortality and morbidity in the intensive care unit (ICU). We performed a study to describe the epidemiology of sepsis syndromes in patients admitted to ICUs of the Piedmont region. METHODS: In this prospective, multicentre, observational study, all 3902 patients admitted to a network of 24 ICUs from 17 hospitals during a 180 day period (April 3-September 29, 2006) were included. Patients were followed from the first day of admission until death or ICU discharge. RESULTS: The incidence of sepsis during the ICU stay was 11.4% (N.=446), corresponding to an incidence of 25 cases/100,000 inhabitants/year; 141 (31.6%) patients had only sepsis, 160 patients had severe sepsis (35.9%) and 145 patients (32.5%) had septic shock In 227 patients (50.9%), sepsis was observed within 48 hours after admission to the ICU, and 219 patients (49.1%) developed ICU-acquired sepsis. The main sources of infection were the lungs, abdomen, and urinary tract. ICU mortality was higher (41.3 vs. 17.3%, P<0.0001) and the median ICU length of stay longer (15 vs. 2 days, P<0.0001) in patients with sepsis than in those without sepsis. The mortality rate increased with the severity of sepsis. ICU-acquired sepsis was associated with higher ICU mortality rates than sepsis occurring within 48 hours of ICU admission (49.8 vs. 33.0%, P<0.0001). CONCLUSION: Sepsis is a common occurrence in critically ill patients. Our data underscore the regional variability in the epidemiology and outcome of sepsis syndromes and may be useful to guide appropriate resource allocation.

Recommendations for anesthesia and perioperative management of patients with neuromuscular disorders.

Patients with neuromuscular disorders are at high risk of intraoperative and postoperative complications. General anesthesia in these patients may exacerbate respiratory and cardiovascular failure due to a marked sensitivity to several anesthetic drugs. Moreover, succinylcholine and halogenated agents can trigger life-threatening reactions, such as malignant hyperthermia, rhabdomyolysis and severe hyperkalemia. Therefore, regional anesthesia should be used whenever possible. If general anesthesia is unavoidable, special precautions must be taken. In particular, for patients at increased risk of respiratory complications (i.e., postoperative atelectasis, acute respiratory failure, nosocomial infections), noninvasive ventilation associated with aggressive airway clearance techniques can successfully treat upper airway obstruction, hypoventilation and airway secretion retention, avoiding prolonged intubation and tracheotomy. Anesthesia and perioperative management of patients with neuromuscular disorders are described in this article. To grade the strength of recommendations and the quality of evidence we adopted the GRADE approach. In case of low-quality evidence, these recommendations represent the collective opinion of the expert panel.

What's new in the "Berlin" definition of acute respiratory distress syndrome?

A valid operative definition for ARDS is essential for the appropriate institution of a standardized 'best-evidence' treatment and for the identification of subgroups of patients who may benefit from specific adjunctive interventions, as well as to assist with prognostication, resource allocation and the design of new research trials. Here, we will discuss some of the methodology used by the ARDS Definition Task Force to develop the new 'Berlin' definition of ARDS, briefly discussing the rationale for the divergence from the AECC definition. The Berlin definition improves on the predictive validity for mortality of the American-European Consensus Conference's (AECC) definition and clarifies both the conceptual model of ARDS and the definition criteria of the syndrome and of its spectrum of severity. This should facilitate case recognition and more consistent treatment strategies based on severity.

Comparison of triple-lumen central venous catheters impregnated with silver nanoparticles (AgTive®) vs conventional catheters in intensive care unit patients.

BACKGROUND: Silver-impregnated central venous catheters (CVCs) have been proposed as a means for preventing CVC colonization and related bloodstream infections (CRBSIs). AIM: To evaluate the efficacy of CVCs impregnated with silver nanoparticles in a large group of critically ill patients. METHODS: A prospective, randomized clinical trial was conducted in five intensive care units (ICUs). Three hundred and thirty-eight adult patients requiring CVCs between April 2006 and November 2008 were randomized to receive AgTive silver-nanoparticle-impregnated (SC) or conventional (CC) CVCs. Primary endpoints were CVC colonization (growth of ≥15 colony-forming units from the catheter tip) and incident CRBSIs (meeting the definitions of the Centers for Disease Control and Prevention). Infection-free time (days from initial CVC insertion to initial blood culture positivity) and ICU mortality rates were measured as secondary endpoints. FINDINGS: The SC group (N = 135) and CC group (N = 137) were similar in terms of clinical and laboratory parameters at baseline, reasons for ICU admission, complications during CVC insertion, and total time with CVC (mean ± standard deviation; SC 13 ± 24 vs CC 15 ± 37 days). No significant intergroup differences were found in CVC colonization rates (SC 32.6% vs CC 30%; P = 0.7), CRBSI incidence rates (3.36 infections per 1000 catheter-days in both groups), infection-free times (SC 13 ± 34 vs CC 12 ± 12 days; P = 0.85) or ICU mortality (SC 46% vs CC 43%; P = 0.7). CONCLUSION: In critically ill patients, use of AgTive(®) silver-nanoparticle-impregnated CVCs had no significant effect on CVC colonization, CRBSI incidence or ICU mortality. These CVCs cannot be recommended as an adjunctive tool for control of CRBSIs.

Bridging to lung transplantation by extracorporeal support.

Ideally, bridging patients with end stage severe respiratory failure to lung transplantation should significantly extend the pretransplant life expectancy to increase the chances to receive a suitable organ, as well as efficiently preserve the post-transplant long-term life expectancy by maintaining physiological homeostasis and avoiding multi-organ dysfunction. Various advanced strategies of extracorporeal circulation can replace at least in part the respiratory function of the lung and can potentially provide the appropriate mode and level of cardiopulmonary support for each patient's physiologic requirements. Therefore, patients on the lung transplant waiting list developing severe hypoxemic and/or hypercapnic respiratory failure can be supported for a prolonged period of time before the transplant, preserving a satisfactory post-transplant life expectancy. However, a more systematic clinical study on this issue is warranted in order to define the actual efficacy of these treatments in reducing the mortality rate on the waiting transplant list, and eventually improve the outcome of patients with end stage respiratory failure.

Invasive and non-invasive long-term mechanical ventilation in Italian children.

BACKGROUND: To date, few studies have been published regarding the number of children in Italy who require long-term mechanical ventilation (LTV) and their underlying diagnoses, ventilatory needs and hospital discharge rate. METHODS: A preliminary national postal survey was conducted and identified 535 children from 57 centers. Detailed data were then obtained for 378 children from 30 centers. RESULTS: The estimated prevalence in Italy of this population was 4.3/100000. The majority of children (72.2%) were followed in pediatric units. The primary physicians who cared for these patients were either pediatric intensivists or pediatric pulmonologists. Neurological patients (78.2% of cases) represented the principal disorder category. 57.2% of the patients were non-invasively ventilated, with a nasal mask being the most common interface (85% of cases). The presence of clinical symptoms that were associated with abnormal findings on diagnostic testing was the primary indication for ventilatory support, whereas weaning failure was the primary indication for tracheotomy. Invasive ventilation was significantly related to younger age, longer daily hours on ventilation and cerebral palsy. Ventilatory modes with guaranteed minimal tidal volume were more often used in patients with tracheotomy. Despite their age, illness severity and need for technological care, 98% of the study population were successfully home discharged. CONCLUSION: Managing pediatric home LTV requires tremendous effort on the part of the patient's family and places a significant strain on community financial resources. In particular, neurological patients require more health care than patients in other categories. To further improve the quality of care for these patients, it is essential to establish a dedicated national database.

Are guidelines for non-invasive ventilation during weaning still valid?

Noninvasive ventilation (NIV) has gained increasing acceptance over the years to reduce endotracheal intubation, pneumonia and to prevent or treat respiratory failure in patients with different diagnoses. The international consensus conference, and the British society guidelines on NIV ventilation have analyzed its use during the weaning phase concluding that there were still conflicting results of its use. However, recent clinical trials have shown clear clinical benefits on the use of NIV in several patient populations during the weaning period. Acute respiratory failure (ARF) during the weaning process is the main object of recently published studies. The latest published randomized trials on the application of NIV for acute respiratory failure following extubation failed to demonstrate any favorable outcome. Even so, the use of NIV during the process of weaning in patients experiencing multiple weaning failure or as a preventive therapy in patients at higher risk of respiratory deterioration showed improved clinical outcomes only in chronic obstructive pulmonary disease and in particular in hypercapnic patients. Reduced invasive mechanical ventilation, tracheostomy and lower mortality rate at 90 days were the major advantages.

Sleep disturbances in the critically ill patients: role of delirium and sedative agents.

BACKGROUND: Impairment of sleep quality and quantity has been described in critically ill patients. Delirium, an organ dysfunction that affects outcome of the critically ill patients, is characterized by an acute onset of impaired cognitive function, visual hallucinations, delusions, and illusions. These symptoms resemble the hypnagogic hallucinations and wakeful dreams seen in patients with neurological degenerative disorders and suffering of disorders of rapid eye movement (REM) sleep. We assessed the characteristics of sleep disruption in a cohort of surgical critically ill patients examining the hypothesis that severe impairments of rapid eyes movement (REM) sleep are associated to delirium. METHODS: Surgical patients admitted to the intensive care units of the San G. Battista Hospital (University of Turin) were enrolled. Once weaning was initiated, sleep was recorded for one night utilizing standard polysomnography. Clinical status, laboratory data on admission, co-morbidities and duration of mechanical ventilation were recorded. Patients were a priori classified as having a "severe REM reduction" or "REM reduction" if REM was higher or lower than 6% of the total sleep time (TST), respectively. Occurrence of delirium during intensive care unit (ICU) stay was identified by CAM-ICU twice a day. Multivariate forward stepwise logistic regression analysis was performed with sleep ("severe REM reduction" vs. "REM reduction") as the a priori dependent factor. RESULTS: REM sleep amounted to 44 (16-72) minutes [11 (8-55) % of the TST] in 14 patients ("REM reduction") and to 2.5 (0-36) minutes [1 (0-6) % of the TST] in the remaining 15 patients ("severe REM reduction") (P = 0.0004). SAPS II on admission was higher in " severely REM deprived" then in "REM deprived" patients. Delirium was present in 11 patients (73.3%) of the patients with "severe REM reduction" and lasted for a median of 3 (0-11) days before sleep assessment, while only one patient having "REM reduction" developed delirium that lasted for 1 day. The factors independently associated with a higher risk of developing "severe REM reduction" were delirium and daily dosage of lorazepam. CONCLUSION: The present study shows that while all critically ill patients present a profound fragmentation of sleep with a high frequency of arousals and awakenings and a reduction of REM sleep, a percentage of patients present an extremely severe reduction of REM sleep. Delirium and daily dosage of lorazepam are the factors independently associated to extremely severe REM sleep reduction.

Long-term home ventilation of children in Italy: a national survey.

BACKGROUND: Improved technology, as well as professional and parental awareness, enable many ventilator-dependent children to live at home. However, the profile of this growing population, the quality and adequacy of home care, and patients' needs still require thorough assessment. OBJECTIVES: To define the characteristics of Italian children receiving long-term home mechanical ventilation (HMV) in Italy. METHODS: A detailed questionnaire was sent to 302 National Health Service hospitals potentially involved in the care of HVM in children (aged <17 years). Information was collected on patient characteristics, type of ventilation, and home respiratory care. RESULTS: A total of 362 HMV children was identified. The prevalence was 4.2 per 100,000 (95% CI: 3.8-4.6), median age was 8 years (interquartile range 4-14), median age at starting mechanical ventilation was 4 years (1-11), and 56% were male. The most frequent diagnostic categories were neuromuscular disorders (49%), lung and upper respiratory tract diseases (18%), hypoxic (ischemic) encephalopathy (13%), and abnormal ventilation control (12%). Medical professionals with nurses (for 62% of children) and physiotherapists (20%) participated in the patients' discharge from hospital, though parents were the primary care giver, and in 47% of cases, the sole care giver. Invasive ventilation was used in 41% and was significantly related to young age, southern regional residence, longer time spent under mechanical ventilation, neuromuscular disorders, or hypoxic (ischemic) encephalopathy. CONCLUSIONS: Care and technical assistance of long-term HMV children need assessment, planning, and resources. A wide variability in pattern of HMV was found throughout Italy. An Italian national ventilation program, as well as a national registry, could be useful in improving the care of these often critically ill children.

The use of CO2 removal devices in patients awaiting lung transplantation: an initial experience.

BACKGROUND: Lung transplantation is the treatment of choice for patients with end-stage lung failure. Limitations are presented by the shortage of donors and the long waiting list periods. New techniques, such as extracorporeal membrane ventilator devices with or without pump support, have been developed as bridges to transplantation for patients with severe, unresponsive respiratory insufficiency. METHODS: Between November 2005 and September 2009, 12 patients (7 males and 5 females), of overall mean age of 43.3 +/- 15.5 years underwent decapneization with extracorporeal devices. In 6 cases, a NovaLung system was used; in the remaining 6 patients, it was a Decap device. Causes of respiratory failure that led to implantation of such devices were cystic fibrosis (n = 6), pulmonary emphysema (n = 5), and chronic rejection of a previous double lung transplant (n = 1). RESULTS: Mean time on extracorporeal decapneization was 13.5 +/- 14.2 days. Eight patients died on the device. Three patients were bridged to lung transplantation; 1 recovered and was weaned from the device after 11 days. Mean PaCO(2) on the extracorporeal gas exchanger was significantly lower for both the devices at 24, 48, and 72 hours after implantation (P < .05). No significant difference was observed for the 2 systems. CONCLUSION: In our initial experience, decapneization devices have been simple, efficient methods to support patients with mild hypoxia and severe hypercapnia that is refractory to mechanical ventilation. This could represent a valid bridge to lung transplantation in these patients.

The effects of inhaled nitric oxide after lung transplantation.

Primary graft failure (PGF) is one of the major complications that occurs immediately following lung transplantation and greatly contributes to increased morbidity and mortality. The incidence of PGF is correlated with a marked decline in endogenous nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) levels. Therefore, the administration of NO during lung transplantation has been proposed as a possible therapeutic treatment to prevent or attenuate PGF pathogenesis. Despite the initial positive results of experimental and uncontrolled clinical trials, recent randomized clinical trials do not support the prophylactic administration of inhaled nitric oxide (iNO) for the prevention of PGF following lung transplantation under the conditions tested. Nonetheless, there is evidence that iNO administration during PGF can improve oxygenation and reduce pulmonary hypertension without altering systemic vascular resistance. This suggests that iNO may prevent the need for extracorporeal membrane oxygenation (ECMO) during the hypoxic phase of PGF. During the intraoperative phase of transplantation, one-lung ventilation (OLV) and pulmonary artery clamping usually increase PVR, causing decreased right ventricular function and hemodynamic instability. The administration of iNO during these lung transplant procedures could decrease right ventricular dysfunction by reducing PVR and help to avoid the use of cardiopulmonary bypass.

Respiratory management of acute respiratory failure in neuromuscular diseases.

Neuromuscular diseases (NMD) can affect all major respiratory muscles, leading to the development of respiratory failure, which is the most common cause of morbidity and mortality in patients affected by those conditions. Based on the clinical onset of acute respiratory failure (ARF), NMD can be classified into two main categories: 1) slowly progressive NMD with acute exacerbations of chronic respiratory failure, and 2) rapidly progressive NMD with acute episodes of respiratory failure. The most common slowly progressive NMDs, such as motor neuron diseases and inherited myopathies, account for the majority of NMD patients developing chronic neuromuscular respiratory failure at risk of acute exacerbations. Conversely, rapidly progressive NMDs, such as Guillain-Barré syndrome and myasthenic crises, are characterized by a sudden onset of ARF, usually in patients with previously normal respiratory function. The patho-physiological mechanisms responsible for ARF in NMD and the variety and complexity of specific challenges presented by the two main categories of NMD will be analyzed in this review, with the aim of providing clinically relevant suggestions for adequate respiratory management of these patients.

Invasive candidiasis and candidemia: new guidelines.

Invasive candidiasis (IC) includes candidemia, disseminated candidiasis with deep organ involvement, endocarditis and meningitis. IC has an attributable mortality of 40% to 50% and is increasingly reported in intensive care units (ICUs). Candida albicans and non-albicans strains are both responsible for infections in ICUs, where empirical and targeted treatments especially need to be initially appropriate. This review synthesizes the most recent guidelines for IC and candidemia from an ICU perspective. Essentially, patients who have been previously exposed to azoles have a higher probability of being infected by azole-resistant or non-albicans strains. Infection site, illness severity, neutropenia, hemodynamic status, organ failure and concomitant drug treatments are host-related factors that influence the choice of anti-fungal treatment. In general, echinocandins are currently favored for empiric treatment of candidemia, especially in critically ill patients or those with previous azole exposure. Pharmacokinetic properties and side effects suggest that polyenes should be avoided in patients with renal failure, and that echinocandins and azoles should be avoided in patients with severe hepatic dysfunction.

How respiratory system mechanics may help in minimising ventilator-induced lung injury in ARDS patients.

The main supportive therapy in acute respiratory distress syndrome patients is mechanical ventilation. As with any therapy, mechanical ventilation has side-effects, and may induce lung injury (ventilator-induced lung injury (VILI)/ventilator-associated lung injury). The mechanical factors responsible for VILI are thought to be related to tidal recruitment/derecruitment of previously collapsed alveoli and/or pulmonary overdistension. The volume/pressure (V/P) curve of the respiratory system in patients as well as in animal models of acute lung injury (ALI) has a characteristic sigmoid shape, with a lower inflection point (LIP) corresponding to the pressure/end-expiratory volume required to initiate recruitment of collapsed alveoli, and an upper inflection point (UIP) corresponding to the pressure/end inspiratory volume at which alveolar overdistension occurs. "Protective" ventilatory approaches have therefore set out to minimise mechanical injury by using the V/P curve to individualise positive end-expiratory pressure (PEEP) (PEEP above the LIP) and tidal volume (by setting end-inspiratory V/P below the UIP) since a large number of experimental studies correlate P/V curves to histological and biological manifestations of VILI and two randomised trials showed that protective ventilatory strategy individually tailored to the P/V curve minimised pulmonary and systemic inflammation and decreased mortality in patients with ALI. However, despite the fact that several studies have: 1) proposed new techniques to perform pressure/volume curves at the bedside, 2) confirmed that the lower inflection point and upper inflection point correspond to computed tomography scan evidence of atelectasis and overdistension, and 3) demonstrated the ability of the pressure/volume curve to estimate alveolar recruitment with positive end-expiratory pressure, no large studies have assessed whether such measurement can be performed in all intensive care units as a monitoring tool to orient ventilator therapy. Preliminary experimental and clinical studies show that the shape of the dynamic inspiratory pressure/time profile during constant flow inflation (stress index), allows prediction of a ventilatory strategy that minimises the occurrence of ventilator-induced lung injury.

The accuracy of transcranial Doppler to detect vasospasm in patients with aneurysmal subarachnoid hemorrhage.

OBJECTIVES: To examine the accuracy of transcranial Doppler to detect cerebral vasospasm in a patient population with aneurysmal subarachnoid hemorrhage. DESIGN: Prospective blind comparison of transcranial Doppler with cerebral angiography. Diagnostic accuracy of transcranial Doppler was assessed using receiver operating characteristic (ROC) analysis and likelihood ratios. Sensitivity and specificity were calculated using directly measured middle cerebral artery diameter as reference standard. SETTING: Intensive Care Unit of a large university teaching hospital. PATIENTS AND PARTICIPANTS: Twenty-two patients with subarachnoid hemorrhage were included. Patients underwent angiography on admission and after 8 days to diagnose vasospasm and were defined as having clinical vasospasm, angiographic vasospasm, or no vasospasm. MEASUREMENTS AND RESULTS: Sensitivity and specificity were 1.00 and 0.75 for angiographic vasospasm and both equal to 1.00 for clinical vasospasm diagnosis. A transcranial Doppler mean velocity threshold value of 100 cm/s for angiographic vasospasm and 160 cm/s for clinical vasospasm detection were chosen by ROC analysis. CONCLUSIONS: A Transcranial Doppler mean velocity threshold of 160 cm/s, calculated by the ROC analysis, accurately detects clinical vasospasm. A daily transcranial Doppler examination performed by a trained operator should be routinely used to provide early identification of patients at high risk and to orient therapeutic decisions.

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

OBJECTIVES: To summarize the prevalence of various forms of acute respiratory failure in acutely ill patients and review the major factors involved in the outcome of these patients. DATA SOURCES AND SELECTION: MEDLINE search for published studies reporting the prevalence or outcome for patients with acute respiratory failure and cited reference studies and abstracts from a recent international meeting in the intensive care medicine field. DATA SYNTHESIS AND EXTRACTION: From the selected articles, information was obtained regarding the prevalence of acute respiratory failure, including acute respiratory distress syndrome and acute lung injury as defined by the North American-European Consensus Conference, the outcome, and the factors influencing mortality rates in this population of patients. CONCLUSIONS: The prevalence of acute respiratory failure varies according to the definition used and the population studied. Nonsurvivors of acute respiratory distress syndrome die predominantly of respiratory failure in <20% of cases. The relatively high mortality rates of acute lung injury/acute respiratory distress syndrome are primarily related to the underlying disease, the severity of the acute illness, and the degree of organ dysfunction.