Prevention of Early Ventilator-Associated Pneumonia after Cardiac Arrest.

This article by Francois et others was published in the New England Journal of Medicine in November 2019 (Volume 381 number 19).
Background:  Patients who are treated with targeted temperature management after out-of-hospital cardiac arrest with shockable rhythm are at increased risk for ventilator-associated pneumonia. The benefit of preventive short-term antibiotic therapy has not been shown.
Methods:  We conducted a multicenter, double-blind, randomized, placebo-controlled trial involving adult patients (>18 years of age) in intensive care units (ICUs) who were being mechanically ventilated after out-of-hospital cardiac arrest related to initial shockable rhythm and treated with targeted temperature management at 32 to 34°C. Patients with ongoing antibiotic therapy, chronic colonization with multidrug-resistant bacteria, or moribund status were excluded. Either intravenous amoxicillin-clavulanate (at doses of 1 g and 200 mg, respectively) or placebo was administered three times a day for 2 days, starting less than 6 hours after the cardiac arrest. The primary outcome was early ventilator-associated pneumonia (during the first 7 days of hospitalization). An independent adjudication committee determined diagnoses of ventilator-associated pneumonia.
Results:  A total of 198 patients underwent randomization, and 194 were included in the analysis. After adjudication, 60 cases of ventilator-associated pneumonia were confirmed, including 51 of early ventilator-associated pneumonia. The incidence of early ventilator-associated pneumonia was lower with antibiotic prophylaxis than with placebo (19 patients [19%] vs. 32 [34%]; hazard ratio, 0.53; 95% confidence interval, 0.31 to 0.92; P = 0.03). No significant differences between the antibiotic group and the control group were observed with respect to the incidence of late ventilator-associated pneumonia (4% and 5%, respectively), the number of ventilator-free days (21 days and 19 days), ICU length of stay (5 days and 8 days if patients were discharged and 7 days and 7 days if patients had died), and mortality at day 28 (41% and 37%). At day 7, no increase in resistant bacteria was identified. Serious adverse events did not differ significantly between the two groups.
Conclusions:  A 2-day course of antibiotic therapy with amoxicillin-clavulanate in patients receiving a 32-to-34°C targeted temperature management strategy after out-of-hospital cardiac arrest with initial shockable rhythm resulted in a lower incidence of early ventilator-associated pneumonia than placebo. No significant between-group differences were observed for other key clinical variables, such as ventilator-free days and mortality at day 28. (Funded by the French Ministry of Health; ANTHARTIC ClinicalTrials.gov number, NCT02186951.).
The printed copy of the New England Journal of Medicine is available in the Health Care Library on D Level of Rotherham Hospital.

Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults

This article by Casey and colleagues was published in the New England in the issue of 28th February 2019
Background:  Hypoxemia is the most common complication during tracheal intubation of critically ill adults and may increase the risk of cardiac arrest and death. Whether positive-pressure ventilation with a bag-mask device (bag-mask ventilation) during tracheal intubation of critically ill adults prevents hypoxemia without increasing the risk of aspiration remains controversial.
Methods:  In a multicenter, randomized trial conducted in seven intensive care units in the United States, we randomly assigned adults undergoing tracheal intubation to receive either ventilation with a bag-mask device or no ventilation between induction and laryngoscopy. The primary outcome was the lowest oxygen saturation observed during the interval between induction and 2 minutes after tracheal intubation. The secondary outcome was the incidence of severe hypoxemia, defined as an oxygen saturation of less than 80%.
Results:  Among the 401 patients enrolled, the median lowest oxygen saturation was 96% (interquartile range, 87 to 99) in the bag-mask ventilation group and 93% (interquartile range, 81 to 99) in the no-ventilation group (P = 0.01). A total of 21 patients (10.9%) in the bag-mask ventilation group had severe hypoxemia, as compared with 45 patients (22.8%) in the no-ventilation group (relative risk, 0.48; 95% confidence interval [CI], 0.30 to 0.77). Operator-reported aspiration occurred during 2.5% of intubations in the bag-mask ventilation group and during 4.0% in the no-ventilation group (P = 0.41). The incidence of new opacity on chest radiography in the 48 hours after tracheal intubation was 16.4% and 14.8%, respectively (P = 0.73).
Conclusions:  Among critically ill adults undergoing tracheal intubation, patients receiving bag-mask ventilation had higher oxygen saturations and a lower incidence of severe hypoxemia than those receiving no ventilation. The printed copy of the New England Journal of Medicine is available in the Health Care Library on D Level of Rotherham Hospital.

Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults

This article by Casey and others was published in the New England Journal of Medicine in February 2019 (Volume 380 issue 9).
Background:  Hypoxemia is the most common complication during tracheal intubation of critically ill adults and may increase the risk of cardiac arrest and death. Whether positive-pressure ventilation with a bag-mask device (bag-mask ventilation) during tracheal intubation of critically ill adults prevents hypoxemia without increasing the risk of aspiration remains controversial.
Methods:  In a multicentre, randomized trial conducted in seven intensive care units in the United States, we randomly assigned adults undergoing tracheal intubation to receive either ventilation with a bag-mask device or no ventilation between induction and laryngoscopy. The primary outcome was the lowest oxygen saturation observed during the interval between induction and 2 minutes after tracheal intubation. The secondary outcome was the incidence of severe hypoxemia, defined as an oxygen saturation of less than 80%.
Results:  Among the 401 patients enrolled, the median lowest oxygen saturation was 96% (interquartile range, 87 to 99) in the bag-mask ventilation group and 93% (interquartile range, 81 to 99) in the no-ventilation group (P = 0.01). A total of 21 patients (10.9%) in the bag-mask ventilation group had severe hypoxemia, as compared with 45 patients (22.8%) in the no-ventilation group (relative risk, 0.48; 95% confidence interval [CI], 0.30 to 0.77). Operator-reported aspiration occurred during 2.5% of intubations in the bag-mask ventilation group and during 4.0% in the no-ventilation group (P = 0.41). The incidence of new opacity on chest radiography in the 48 hours after tracheal intubation was 16.4% and 14.8%, respectively (P = 0.73).
Conclusions:  Among critically ill adults undergoing tracheal intubation, patients receiving bag-mask ventilation had higher oxygen saturations and a lower incidence of severe hypoxemia than those receiving no ventilation.
The printed copy of the New England Journal of Medicine is available in the Health Care Library on D Level of Rotherham Hospital.

Effect of Jet Nebulization on Noninvasive Positive-Pressure Ventilation Administered with Noninvasive or Intensive Care Unit Ventilators: A Bench Study

This article by Xu and colleagues was published in the December 2018 issue of Respiration international review of thoracic diseases.
Background:  Most of the patients on non invasive positive pressure ventilation require aerosol inhalation therapy to moisturize the airways or deliver drugs in acute settings. However, the effect of jet nebulization on non invasive positive pressure ventilation (NPPV) has not been determined.
Objectives:  This study was designed to investigate the impact of jet nebulization on NPPV applied in ventilators.
Methods:  Aerosol therapy during NPPV was conducted in a simulated lung. The jet nebulizer was connected at both the distal and proximal end of the exhalation valve for the noninvasive ventilators, while it was placed both in front of the Y tube proximal to the patient and at 15 cm distance from the Y-tube inspiratory limb distal to the patient for the intensive care unit (ICU) ventilators. Driving flow was set at 4 and 8 L/min, respectively.
Results:  TPmin (time from the beginning of the lung simulator’s inspiratory effort to the lowest value of airway pressure needed to trigger the ventilator), Ttrig (time to trigger), and Ptrig (the magnitude of airway pressure drop needed to trigger) were not significantly altered by jet nebulization in the non-invasive ventilators, while they were significantly increased in the ICU ventilators. The greater the driving flow, the stronger the impact on TPmin, Ttrig, and Ptrig. The actual tidal volume and control performance were not significantly affected by jet nebulization in either non-invasive or ICU ventilators. The tidal volume monitored was significantly increased at 8 L/min driving flow. The greater the driving flow, the stronger the impact on the tidal volume monitored.
Conclusion:  The effect of jet nebulization on NPPV was different when compared to invasive ventilation. Jet nebulization only affected the tidal volume monitored in the non-invasive ventilator. Jet nebulization also affected the triggering performance and tidal volume monitored in the ICU ventilator.
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Effect of a Low vs Intermediate Tidal Volume Strategy on Ventilator-Free Days in Intensive Care Unit Patients without ARDS: A Randomized Clinical Trial.

This article by the Writing Group for the PReVENT Investigators was published in JAMA in November 2018.
Importance:  It remains uncertain whether invasive ventilation should use low tidal volumes in critically ill patients without acute respiratory distress syndrome (ARDS).
Objective:  To determine whether a low tidal volume ventilation strategy is more effective than an intermediate tidal volume strategy.
Design,Setting, and Participants:  A randomized clinical trial, conducted from September 1, 2014, through August 20, 2017,including patients without ARDS expected to not be extubated within 24 hours after start of ventilation from 6 intensive care units in the Netherlands.
Interventions:  Invasive ventilation using low tidal volumes(n = 477) or intermediate tidal volumes (n = 484).
Main Outcomes and Measures:  The primary outcome was the number of ventilator-free days and alive at day 28. Secondary outcomes included length of ICU and hospital stay; ICU, hospital, and 28- and 90-day mortality; and development of ARDS, pneumonia, severe atelectasis, orpneumothorax.
Results:  In total, 961 patients (65% male), with a median age of 68 years (interquartile range [IQR], 59-76), were enrolled. Atday 28, 475 patients in the low tidal volume group had a median of 21 ventilator-free days (IQR, 0-26), and 480 patients in the intermediate tidal volume group had a median of 21 ventilator-free days (IQR, 0-26) (mean difference, -0.27 [95% CI, -1.74 to 1.19]; P = .71). There was no significant difference in ICU (median, 6 vs 6 days; 0.39 [-1.09 to 1.89]; P = .58) and hospital (median, 14 vs 15 days; -0.60 [-3.52 to 2.31]; P = .68) length of stayor 28-day (34.9% vs 32.1%; hazard ratio [HR], 1.12 [0.90 to 1.40]; P = .30) and90-day (39.1% vs 37.8%; HR, 1.07 [0.87 to 1.31]; P = .54) mortality. There was no significant difference in the percentage of patients developing the following adverse events: ARDS (3.8% vs 5.0%; risk ratio [RR], 0.86 [0.59 to 1.24];P = .38), pneumonia (4.2% vs 3.7%; RR, 1.07 [0.78 to 1.47]; P = .67), severeatelectasis (11.4% vs 11.2%; RR, 1.00 [0.81 to 1.23]; P = .94), and pneumothorax (1.8% vs 1.3%; RR, 1.16 [0.73 to 1.84]; P = .55).  
Conclusions and Relevance:  In patients in the ICU without ARDS who were expected not to be extubated within 24 hours of randomization, a low tidal volume strategy did not result in a greater number of ventilator-free days than an intermediate tidal volume strategy.
The print copy of this issue JAMA is available in the Healthcare Library on D Level of Rotherham General Hospital.  The full text of the article should be available using a Rotherham NHS Athens password one month after publication via this link.

Intensive care doctors’ preferences for arterial oxygen tension levels in mechanically ventilated patients

This research by Schjørring and colleagues was published in Acta Anaesthesiologica Scandinavica in November 2018.
Background:  Oxygen is liberally administered in intensive care units (ICUs). Nevertheless, ICU doctors’ preferences for supplementing oxygen are inadequately described. The aim was to identify ICU doctors’ preferences for arterial oxygenation levels in mechanically ventilated adult ICU patients.
Methods:  In April to August 2016, an online multiple-choice 17-part-questionnaire was distributed to 1080 ICU doctors in seven Northern European countries. Repeated reminder e-mails were sent. The study ended in October 2016.
Results:  The response rate was 63%. When evaluating oxygenation 52% of respondents rated arterial oxygen tension (PaO2 ) the most important parameter; 24% a combination of PaO2 and arterial oxygen saturation (SaO2 ); and 23% preferred SaO2 . Increasing, decreasing or not changing a default fraction of inspired oxygen of 0.50 showed preferences for a PaO2 around 8 kPa in patients with chronic obstructive pulmonary disease, a PaO2 around 10 kPa in patients with healthy lungs, acute respiratory distress syndrome or sepsis, and a PaO2 around 12 kPa in patients with cardiac or cerebral ischaemia. Eighty per cent would accept a PaO2 of 8 kPa or lower and 77% would accept a PaO2 of 12 kPa or higher in a clinical trial of oxygenation targets.
Conclusion:  Intensive care unit doctors preferred PaO2 to SaO2 in monitoring oxygen treatment when peripheral oxygen saturation was not included in the question. The identification of PaO2 as the preferred target and the thorough clarification of preferences are important when ascertaining optimal oxygenation targets. In particular when designing future clinical trials of higher vs lower oxygenation targets in ICU patients.
To access the full text of this article via the journal’s homepage you require a personal subscription to the journal.  Some articles may be available freely without a password.  Library members can order individual articles via the Rotherham NHS Foundation Trust Library and Knowledge Service using the article requests online via this link.

Effect of a Low vs Intermediate Tidal Volume Strategy on Ventilator-Free Days in Intensive Care Unit Patients Without ARDS: A Randomized Clinical Trial

This article by the Writing Group for PReVENT Investigators was published in JAMA during October 2018.
Importance:  It remains uncertain whether invasive ventilation should use low tidal volumes in critically ill patients without acute respiratory distress syndrome (ARDS).
Objective:  To determine whether a low tidal volume ventilation strategy is more effective than an intermediate tidal volume strategy.
Design, Setting, and Participants:  A randomized clinical trial, conducted from September 1, 2014, through August 20, 2017, including patients without ARDS expected to not be extubated within 24 hours after start of ventilation from 6 intensive care units in the Netherlands.
Interventions:  Invasive ventilation using low tidal volumes (n = 477) or intermediate tidal volumes (n = 484).
Main Outcomes and Measures:  The primary outcome was the number of ventilator-free days and alive at day 28. Secondary outcomes included length of ICU and hospital stay; ICU, hospital, and 28- and 90-day mortality; and development of ARDS, pneumonia, severe atelectasis, or pneumothorax.
Results:  In total, 961 patients (65% male), with a median age of 68 years (interquartile range [IQR], 59-76), were enrolled. At day 28, 475 patients in the low tidal volume group had a median of 21 ventilator-free days (IQR, 0-26), and 480 patients in the intermediate tidal volume group had a median of 21 ventilator-free days (IQR, 0-26) (mean difference, -0.27 [95% CI, -1.74 to 1.19] P = .71). There was no significant difference in ICU (median, 6 vs 6 days; 0.39 [-1.09 to 1.89] ; P = .58) and hospital (median, 14 vs 15 days; -0.60 [-3.52 to 2.31]; P = .68) length of stay or 28-day (34.9% vs 32.1%; hazard ratio [HR], 1.12 [0.90 to 1.40]; P = .30) and 90-day (39.1% vs 37.8%; HR, 1.07 [0.87 to 1.31]; P = .54) mortality. There was no significant difference in the percentage of patients developing the following adverse events: ARDS (3.8% vs 5.0%; risk ratio [RR], 0.86 [0.59 to 1.24]; P = .38), pneumonia (4.2% vs 3.7%; RR, 1.07 [0.78 to 1.47]; P = .67), severe atelectasis (11.4% vs 11.2%; RR, 1.00 [0.81 to 1.23]; P = .94), and pneumothorax (1.8% vs 1.3%; RR, 1.16 [0.73 to 1.84]; P = .55).
Conclusions and Relevance:  In patients in the ICU without ARDS who were expected not to be extubated within 24 hours of randomization, a low tidal volume strategy did not result in a greater number of ventilator-free days than an intermediate tidal volume strategy.
The print copy of this issue JAMA is available in the Healthcare Library on D Level of Rotherham General Hospital.