Comparative evaluation of three interfaces for non-invasive ventilation: a randomized cross-over design physiologic study on healthy volunteers

Introduction: Interface choice is crucial for non-invasive ventilation (NIV) success. We compared a new interface, the helmet next (HN), with the facial mask (FM) and the standard helmet (HS) in twelve healthy volunteers.Methods: In this study, five NIV trials were randomly applied, preceded and followed by a trial of unassisted spontaneous breathing (SB). Baseline settings, for example, 5 cmH2O of both inspiratory pressure support (PS) and positive end-expiratory pressure (PEEP), were applied through FM, HS and HN, while increased settings (PS and PEEP of 8 cmH2O) were only applied through HS and HN. We measured flow, airway, esophageal and gastric pressures, and calculated inspiratory effort indexes and trigger delays. Comfort was assessed with a visual-analog-scale.Results: We found that FM, HS and HN at baseline settings were not significantly different with respect to inspiratory effort indexes and comfort. Inspiratory trigger delay and time of synchrony (TI,synchrony) were significantly improved by FM compared to both helmets, whereas expiratory trigger delay was shorter with FM, as opposed to HS only. HN at increased settings performed better than FM in decreasing inspiratory effort measured by pressure-time product of transdiaphragmatic pressure (PTPdi)/breath (10.7 ± 9.9 versus 17.0 ± 11.0 cmH2O*s), and PTPdi/min (128 ± 96 versus 204 ± 81 cmH2O*s/min), and PTPdi/L (12.6 ± 9.9 versus 30.2 ± 16.8 cmH2O*s/L). TI, synchrony was inferior between HN and HS at increased settings and FM.Conclusions: HN might hold some advantages with respect to interaction and synchrony between subject and ventilator, but studies on patients are needed to confirm these findings.Trial registration: ClinicalTrials.gov NCT01610960

Cytomegalovirus and herpes simplex virus effect on the prognosis of mechanically ventilated patients suspected to have ventilator-associated pneumonia.

OBJECTIVE: Cytomegalovirus (CMV) and herpes simplex virus (HSV) are common viruses that can affect critically ill patients who are not immunocompromised. The aim of this study was to determine whether the identification of CMV and/or HSV in mechanically ventilated critically ill patients suspected of having pneumonia was associated with an increased mortality. DESIGN: Prospective epidemiological study. SETTING: Medical intensive care unit of a tertiary medical center. PATIENTS: Ninety-three patients with suspected pneumonia. INTERVENTIONS: Patients with suspected pneumonia had bronchoalveolar lavage and blood samples taken to confirm the diagnosis. Antigenemia was used to detect CMV in the blood. Bronchoalveolar lavage samples were submitted to testing using quantitative real-time Polymerase Chain Reaction. MEASUREMENTS AND MAIN RESULTS: We identified 22 patients with a CMV infection, 26 patients with an HSV infection and 45 patients without CMV or HSV infection (control group). Mortality at day 60 was higher in patients with a CMV infection than in patients from the control group (55% vs. 20%, P<0.01). Mortality at day 60 was not significantly increased in the group with HSV infection. Duration of ICU stay and ICU mortality were significantly higher in patients with CMV infections when compared to patients from the control group, whereas ventilator free days were significantly lower in patients with CMV infections when compared to patients from the control group. CONCLUSIONS: In critically ill patients, a CMV infection is associated with an increased mortality. Further interventional studies are needed to evaluate whether treatment could improve the prognosis

Meta-analyse of the mortality associated with Cytomegalovirus (CMV) Diagnosis methods are detailed in <b>table 5</b>.

<p>Meta-analyse of the mortality associated with Cytomegalovirus (CMV) Diagnosis methods are detailed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051340#pone-0051340-t005" target="_blank"><b>table 5</b></a>.</p

Viral load on bronchoalveolar lavage for herpes simplex virus (<b>Figure 1A</b>) and cytomegalovirus (<b>Figure 1B</b>) according to mortality at day 60.

<p>Viral load on bronchoalveolar lavage for herpes simplex virus (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051340#pone-0051340-g001" target="_blank"><b>Figure 1A</b></a>) and cytomegalovirus (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051340#pone-0051340-g001" target="_blank"><b>Figure 1B</b></a>) according to mortality at day 60.</p

Diagnosis Methods used to diagnose CMV infection.

<p>BAL, bronchoalveolar lavage; PCR, polymerase chain reaction.</p

Meta-analyse of the mortality associated with Herpes Simplex Virus (HSV) Diagnosis methods are detailed in <b>table 6</b>.

<p>Meta-analyse of the mortality associated with Herpes Simplex Virus (HSV) Diagnosis methods are detailed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051340#pone-0051340-t006" target="_blank"><b>table 6</b></a>.</p

Outcomes.

<p>ICU, intensive care unit; ARDS, acute respiratory distress syndrome; VAP, ventilator-associated pneumonia; BAL, bronchoalveolar lavage; VFD, ventilator-free days.</p>*<p><i>p</i><0.01 <i>vs.</i> the No HSV – No CMV group;</p>†<p><i>p</i><0.05 <i>vs.</i> the No HSV – No CMV group;</p>‡<p><i>p</i><0.016 <i>vs.</i> the HSV group.</p

Characteristics of patients at the time of diagnosis.

<p>CPIS, clinical pulmonary infection score; SOFA, sequential organ failure assessment score; NMBA, Neuromuscular blocking agents; massive blood transfusion, replacement of a patient’s total blood volume in less than 24 hours;</p>*<p><i>p</i><0.05 <i>vs.</i> No HSV – No CMV.</p

Diagnosis Methods used to diagnose HSV infection.

<p>BAL, bronchoalveolar lavage; PCR, polymerase chain reaction.</p