Tag Archives: Pulmonary

Sevoflurane for Sedation

Sevoflurane improves gas exchange, and reduces alveolar edema and inflammation in preclinical studies of lung injury, but its therapeutic effects have never been investigated in acute respiratory distress syndrome (ARDS). Jabaudon et al set out to assess whether sevoflurane would improve gas exchange and inflammation in ARDS.

They found that in patients with ARDS, use of inhaled sevoflurane improved oxygenation and decreased levels of a marker of epithelial injury and of some inflammatory markers, compared with midazolam.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

High-Flow Nasal Cannula vs. Noninvasive Ventilation

High-flow conditioned oxygen therapy delivered through nasal cannulae and noninvasive mechanical ventilation (NIV) may reduce the need for reintubation. Therefore, Hernández et al set out to test if high-flow conditioned oxygen therapy is noninferior to NIV for preventing postextubation respiratory failure and reintubation in patients at high risk of reintubation.

They found that among high-risk adults who have undergone extubation, high-flow conditioned oxygen therapy was not inferior to NIV for preventing reintubation and postextubation respiratory failure.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Airway Driving Pressure and Lung Stress in ARDS Patients

Since the first description of acute respiratory distress syndrome (ARDS) in the 1960s, numerous studies have sought the optimal tidal volume, positive end-expiratory pressure, plateau pressure, and inspired fraction of oxygen to reduce ventilator-induced lung injury. Chiumello et al set out to evaluate if airway driving pressure could accurately predict lung stress in ARDS patients.

They found that airway driving pressure can detect lung overstress with an acceptable accuracy.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

EIP Prolongation in ARDS Patients

End-inspiratory pause (EIP) prolongation decreases dead space-to-tidal volume ratio and partial pressure of carbon dioxide in arterial blood (PaCO2). We do not know the physiological benefits of this approach to improve respiratory system mechanics in acute respiratory distress syndrome (ARDS) patients when mild hypercapnia is of no concern. Aguirre-Bermeo et al, therefore, set out to address this unknown.

They found that prolonging EIP allowed a significant decrease in tidal volume without changes in PaCO2 in passively ventilated ARDS patients. This produced a significant decrease in plateau pressure and driving pressure and significantly increased respiratory system compliance, which suggests less overdistension and less dynamic strain.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Sedatives and Their Associations with VAEs and Time to Extubation

Sedative selection is crucial to outcomes in critically ill patients. While benzodiazepines are known to be associated with a longer duration of mechanical ventilation compared to propofol and dexmedetomidine, little data exist comparing these sedatives in association with ventilator-associated events (VAEs). Klompas et al therefore aimed to evaluate the association between these sedatives, VAEs and time to extubation.

They found that sedatives vary in their associations with VAEs and time to extubation but not in their associations with time to hospital discharge or mortality.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Delirium and the Efficacy of Dexmedetomidine

Some contend that effective therapy has not been established for patients with agitated delirium receiving mechanical ventilation. Therefore, Reade et al set out to determine the effectiveness of dexmedetomidine when added to standard care in patients with agitated delirium receiving mechanical ventilation.

They found that among patients with agitated delirium receiving mechanical ventilation in the intensive care unit, the addition of dexmedetomidine to standard care (compared with standard care alone [placebo]) resulted in more ventilator-free hours at seven days.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Use of High-Flow Oxygen Therapy in Low-Risk Postextubation Patients

Studies of mechanically ventilated critically ill patients that combine populations that are at high and low risk for reintubation suggest that conditioned high-flow nasal cannula oxygen therapy after extubation improves oxygenation compared with conventional oxygen therapy. However, conclusive data about reintubation are lacking. Therefore, Hernández et al set out to determine whether high-flow nasal cannula oxygen therapy is superior to conventional oxygen therapy for preventing reintubation in mechanically ventilated patients at low risk for reintubation.

They found that among extubated patients at low risk for reintubation, the use of high-flow nasal cannula oxygen compared with conventional oxygen therapy reduced the risk of reintubation within 72 hours.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Chronic Hypoxemia in Children with CHD Mars Airway Epithelial Na+ Transport

Ambient hypoxia impairs the airway epithelial Na+ transport, which is crucial in lung edema reabsorption. Whether chronic systemic hypoxemia affects airway Na+ transport has remained largely unknown. Kaskinen et al have therefore investigated whether chronic systemic hypoxemia in children with congenital heart defect affects airway epithelial Na+ transport, Na+ transporter-gene expression, and short-term lung edema accumulation.

They found that the impaired airway epithelial amiloride-sensitive Na+ transport activity in profoundly hypoxemic children with cyanotic congenital heart defect may hinder defense against lung edema after cardiac surgery.

Read the full Concise Critical Appraisal by logging in to the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Impact of Initial CVP on Outcomes of Fluid Management Strategies in ARDS

In acute respiratory distress syndrome, conservative fluid management increases ventilator-free days without affecting mortality. Response to fluid management may differ based on patients’ initial central venous pressure. Semler et al hypothesized that initial central venous pressure would modify the effect of fluid management on outcomes.

They found that conservative fluid management decreases mortality for acute respiratory distress syndrome patients with a low initial central venous pressure.

Read the full Concise Critical Appraisal by logging in to the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Tidal Volume and Its Association with Noninvasive Ventilation Outcome

A low or moderate expired tidal volume can be difficult to achieve during noninvasive ventilation for de novo acute hypoxemic respiratory failure. To see if this is a cause for concern, Carteaux et al set out to assess expired tidal volume and its association with noninvasive ventilation outcome.

They found that a low expired tidal volume is almost impossible to achieve in the majority of patients receiving noninvasive ventilation for de novo acute hypoxemic respiratory failure, and a high expired tidal volume is independently associated with noninvasive ventilation failure.
Read the full Concise Critical Appraisal by logging in to the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Use of Budesonide/Surfactant to Prevent Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is one of the most common complications in premature infants and is characterized by lung injury that affects alveolar and pulmonary vascular development. Yeh et al sought to compare intra-tracheal administration of surfactant/budesonide with that of surfactant alone on the incidence of death or BPD in very-low-birth-weight infants with severe respiratory distress syndrome.

They found that in very-low-birth-weight infants with severe respiratory distress syndrome, intra-tracheal administration of surfactant/budesonide compared with surfactant alone significantly decreased the incidence of BPD without immediate adverse effect.

Read the full Concise Critical Appraisal by logging in to the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

The Utility of High-Flow Nasal Cannula in Acute Hypoxic Respiratory Failure

High-flow nasal cannula (HFNC) is a relatively new technology that allows clinicians to treat patients with severe hypoxemia using significantly larger, humidified gas flows compared to traditional nasal cannula. Frat and colleagues compared the outcomes of patients with hypoxemic respiratory failure who were treated with HFNC, a combination of noninvasive positive-pressure ventilation and HFNC, and standard face mask oxygen therapy.

The authors found no difference in endotracheal intubation rates among the three groups at 28 days (their predefined primary outcome). However, an improvement in 90-day mortality and in subjective patient comfort was noted with HFNC over the other two treatment arms.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Predicting Weaning-Induced Cardiac Dysfunction

Weaning-induced cardiac dysfunction is one of the most frequent and treatable causes of weaning failure. Dres et al initiated a study to determine whether the presence of cardiac preload independence before a spontaneous breathing trial (SBT) is associated with weaning failure related to cardiac dysfunction.

They found that detection of cardiac preload independence by passive leg raising (PLR) performed before an SBT reliably predicted the occurrence of weaning-induced cardiac dysfunction. These study results provide compelling support for using PLR as an assessment tool for SBT failure. It is now a matter of waiting for confirmatory studies.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Driving Pressure and Survival in the Acute Respiratory Distress Syndrome

Protective lung strategies—low tidal volumes (Vt), increased positive end-expiratory pressures (PEEP) and lower plateau pressures (Pplat)—have been the mainstay of acute respiratory distress syndrome (ARDS) treatment, thought to confer survival benefit by reducing mechanical damage to the lungs. However, strategies can conflict, and the net negative effect of sacrificing one parameter for another is unclear. Because respiratory-system compliance (Crs) is strongly related to the volume of aerated remaining functional lung during disease (termed functional lung size), Amato et al hypothesized that driving pressure (ΔP = Vt/Crs), in which Vt is intrinsically normalized to functional lung size (instead of predicted lung size in healthy persons), would be an index more strongly associated with survival than Vt or PEEP in patients with ARDS who are not actively breathing.

They found that driving pressure was the ventilation variable that best stratified risk. Decreases in driving pressure owing to changes in ventilator settings were strongly associated with increased survival.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.

Noninvasive Ventilation for Severe Exacerbations of COPD

Noninvasive ventilation (NIV) can be used for patients with chronic obstructive pulmonary disease (COPD), and previous reports have demonstrated a survival benefit when NIV is used in carefully selected patient populations. Lindenauer and colleagues sought to compare the outcomes for patients with COPD treated with NIV versus invasive mechanical ventilation (IMV) using data from a network of U.S. hospitals reporting to a voluntary, fee-supported quality improvement database.

The authors found that patients with COPD treated with NIV at the time of hospitalization had lower inpatient mortality, shorter length of stay and lower costs compared to those treated with IMV. A major strength of this study is the use of a large, externally generalizable population. As with all observational studies, however, residual confounding remains a methodological flaw, which the authors attempted to control for with advanced statistical techniques. All said, among patients hospitalized for COPD exacerbations, NIV seems to be a prudent initial choice for ventilatory support based on the results of this study.

Read the full Concise Critical Appraisal by logging into the SCCM eCommunity. Concise Critical Appraisal is a regular feature aimed at highlighting the best and most relevant literature from a variety of academic journals and encouraging discussion around recent studies and research.