Atelectasis, Pneumonia
Conditions
Keywords
Atelectasis, Pneumonia, Lung ultrasound, Doppler
Brief summary
In infectious lung consolidations, the inhibition of hypoxic pulmonary vasoconstriction (HPV) results in a higher regional acceleration time (RAcT) compared to the RAcT measured in atelectatic consolidations.
Detailed description
Ventilator-associated pneumonia has a considerable impact on morbidity and mortality in intensive-care patients. Chest radiography, which is the most frequently used imagery test for bedside lung evaluation in mechanically ventilated patients, is recognized to be poorly sensitive and non-specific for the diagnosis of ventilator-associated pneumonia. Bronchoalveolar lavage using a bronchoscope remains the most reliable tool for the diagnosis of this nosocomial infection. However, a bronchoscopy may not be feasible in all patients and waiting time before final results become available may cause a delay in the initiation of the treatment, thus increasing the risk of mortality. Lung ultrasound is a promising non-invasive, non-radiant, portable and easy to use tool especially in critically-ill patients. Dependent atelectasis is a frequent phenomenon in mechanically ventilated patients. The presence of clinical infection signs raises the question of the nature of the infiltrate. A consolidation of infectious nature differs from atelectasis by its local hypoxic pulmonary vasoconstriction inhibition. In patients breathing spontaneously, it is possible to detect this difference using the RAcT, measured by pulsed-wave Doppler in an arterial blood vessel located in a pulmonary consolidation visible by ultrasound examination. The use of pulsed-wave Doppler to measure the RAcT in a consolidation added to the value of general lung ultrasound could help determine the infectious or atelectatic nature of a consolidation in mechanically ventilated patients. However, the RAcT has never been studied in patients under positive pressure ventilation. In this observational study, the investigators will explore the role of measuring the RAcT and of general lung ultrasound as a diagnostic tool to detect pneumonia in mechanically ventilated patients.
Interventions
OTHERLung ultrasound and Doppler (Day 0)
In patients presenting a consolidation of suspected atelectatic nature, a lung ultrasound examination using pulsed-wave Doppler will be performed on Day 0.
Sponsors
Centre de Recherche du Centre Hospitalier de l'Université de Montréal
Centre hospitalier de l'Université de Montréal (CHUM)
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Under mechanical ventilation and presenting one or more consolidations on chest radiography or CT scan
Exclusion criteria
* Participation to another study * Poor echogenicity (morbid obesity, multiple thoracic dressings) * Contra-indications to superior limbs or torso mobilization * Contra-indications to bronchoscopy * Antibiotics initiated more than 24 hours but less than 72 hours before inclusion or changes in the antibiotic regimen in the last 72 hours.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| RAcT in lung consolidations | During lung ultrasound examination - Day 0 | Regional acceleration time measured by lung ultrasound and pulsed-wave Doppler |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Presence of visible blood vessels on colour Doppler in lung consolidations | During lung ultrasound examination - Day 0 | Graded semi-quantitatively (absence, single, multiple branching) |
| Presence of dynamic air bronchograms in lung consolidations | During lung ultrasound examination - Day 0 | To-and-fro respiratory movement of punctiform or linear hyperechoic artifacts (absence or presence) |
| Presence of sub-pleural consolidations | During lung ultrasound examination - Day 0 | Subpleural hypoechoic area with ragged margins (absence or presence) |
Countries
Canada
Contacts
Primary ContactMartin Girard, MD, FRCPC
Outcome results
None listed