Intrabronchial Airway Pressures in Intubated Patients During Bronchoscopy

Study Overview
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Brief Summary
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The purpose of this study is to examine changes in ventilation and airway pressures during conventional bronchoscopy of intubated patients.

Detailed Description
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Mechanically ventilated patients often need bronchoscopy as a diagnostic procedure or for visually directed elimination of secretions. Partial endotracheal tube occlusion by the bronchoscope increases airflow resistance. Inhibition of inspiratory flow may be compensated for by augmented inspiratory pressure. Reduced expiratory flow however, cannot be compensated for by most ventilators and could lead to higher airway - and intrathoracic pressures that are not detected by pressure transducers in the ventilator tubing. In this study we compare changes in ventilation, airway pressures, ventilator pressures and blood gases during bronchoscopy of intubated patients in both volume controlled and pressure controlled ventilation. Our hypothesis are that 1) increased resistance in the tube during bronchoscopy leads to high intrabronchial airway pressures when the ventilator is in volume controlled mode, and 2) when the ventilator is in pressure controlled mode, increased resistance in the tube during bronchoscopy leads to reduced Tidal Volume and moderately increased paCO2.

Official Title
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Intrabronchial Airway Pressures in Intubated Patients During Bronchoscopy Under Volume Controlled (VC) and Pressure Controlled (PC) Ventilation

Conditions
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Acute Respiratory Distress Syndrome, Acute Lung Injury (ALI)

Intervention / Treatment
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* Other: Bronchoscopy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ARDS/ALI patients on mechanical ventilation endotracheal tube size 7-9mm age > 18 years therapeutic or diagnostic bronchoscopy requested by staff physician Exclusion Criteria: SpO2 < 90% unstable BP pneumothorax acute cardiovascular disease cerebrovascular or other condition that requires stable BP and saturation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ARDS / ALI patients<br> | Other: Bronchoscopy<br>* Airway pressures, ventilation changes and blood gas changes are recorded in a group of intubated patients on mechanical ventilation before and after bronchoscope insertion. The registration is done immediately before a therapeutic/diagnostic bronchoscopy requested by a staff physician not involved n the study.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in ventilation, airway pressures and blood gases after bronchoscope insertion. | paO2, paCO2 (kPa), airway and ventilator pressures (cmH2O) | 2 minutes after bronchoscope insertion/ mode change |