Changes in lung volumes during bronchoalveolar lavage according to bedside position. Case Series

Abstract

Introduction: Bronchoalveolar lavage (BAL) is used in the diagnosis of pneumonia in patients with Mechanical Ventilation. Its performance involves the instillation of saline solution, which is associated with lung collapse and worsening hypoxemia. Positioning the patient9s head at 0° could increase the loss of lung volume and oxygenation. A therapeutic option to mitigate this effect could be to perform this procedure with head elevation at 30°. Aims and Objectives: The study aimed to assess changes in lung volumes in relation to the position of the patient9s head. Methods: Case series of 3 patients. End-expiratory Lung Impedance (EELI) measurements were performed (Pulmovista V500) in the following situations: Head at 30° before BAL, 0° before BAL, 0° post-BAL and 30° post-BAL. Results: In patients 1 and 2, the change of headrest from 30° to 0° before BAL resulted in an overall decrease in EELI (83.1% - 20.2%). Performing BAL increased the drop in EELI, with greater expression in the regions where BAL was performed. After BAL was completed, in both patients, the repositioning of the headrest to 30° produced an increase in global EELI without reaching the values obtained with the headrest at 30° before BAL (Patient 1 80.5% - Patiente 2 52.9%). In patient 3, the change of head position from 30° to 0° after BAL showed a 12.5% decrease in EELI. Performing BAL deepened the drop in overall EELI (-44.4%), as did repositioning the headrest to 30° (-70%) post-BAL. Conclusion: Changes in bedside positioning before BAL resulted in a reduction in EELI in all 3 patients. The repositioning of the head after BAL had a heterogeneous behavior increasing the EELI in patients 1 and 2, and decreasing it in patient 3