Fiberoptic Bronchoscopy and Bronchoalveolar Lavage in Critically Ill Ventilated Patients: Impact on Respiratory Mechanics and Gas Exchange

Fiberoptic bronchoscopy (FOB) is widely used in intensive care units as a diagnostic or therapeutic procedure. FOB in respiratory failure patients supported by mechanical ventilation may worsen hypoxemia and hypercapnia, therefore FOB requires careful consideration in this patient population. The generally accepted indications for FOB in ventilated patients are removal of retained secretions, resolution of atelectasis and evaluation of hemoptysis. A diagnostic indication is the bronchoalveolar lavage (BAL), to sample the lower respiratory tract without contamination. Studies of FOB performed in mechanically ventilated patients suggest an acceptable safety profile, except for the occurrence of hypoxemia as the main adverse event. Bronchoalveolar Lavage (BAL) in normal volunteers is reported to be safe and does not lead to measurable changes in pulmonary function parameters. However, in intensive care patients may suffer from serious side effects such as prolonged oxygen desaturation. Moreover, reductions in arterial oxygen tension (PaO2) have been reported to persist in some patients for 4 h and more after the procedure. Authors reported the BAL procedure is associated to a worsening of PaO2/FiO2 ratio, in several ARDS patients the drop in PaO2 was higher than 30%. Moreover a physiological study in patients undergoing FOB and BAL showed adverse change in lung compliance and resistance.

The purpose of this prospective study is to determine the alterations in respiratory mechanics (regional compliance and resistance) and gas exchange induced by FOB and BAL up to 6 hours after the procedure. The lung regional ventilation evaluation will be made by electrical impedance tomography (EIT).