Transpulmonary thermodilution enables to detect small short-term changes in extravascular lung water induced by a bronchoalveolar lavage

Abstract

Objective: To take the opportunity of a bronchoalveolar lavage to challenge the transpulmonary thermodilution for detecting the time course of changes in extravascular lung water.

Design: Observational study.

Setting: Medical ICU.

Patients: Mechanically ventilated patients in whom a bronchoalveolar lavage by bronchoscopy was performed.

Intervention: Transpulmonary thermodilution before and after bronchoalveolar lavage.

Measurements and main results: Before and at different times after bronchoalveolar lavage, transpulmonary thermodilution was performed to record the value of indexed extravascular lung water. For each measurement, the values of three thermodilution measurements were averaged at the following steps: before bronchoalveolar lavage, after bronchoalveolar lavage, and 1 hour, 2 hours, 4 hours, and 6 hours after bronchoalveolar lavage. The amount of saline infusion left in the lungs after bronchoalveolar lavage was also recorded. Twenty-five patients with suspicion of pneumonia were included. Twenty-eight bronchoalveolar lavages were finally analyzed. On average, 200 mL (180-200 mL) of saline were injected and 130 mL (100-160 mL) were left in the lungs. Between before and immediately after bronchoalveolar lavage, indexed extravascular lung water significantly increased from 12 ± 4 to 15 ± 5 mL/kg, respectively, representing a 169 ± 166 mL increase in nonindexed extravascular lung water. After bronchoalveolar lavage, the value of indexed extravascular lung water was significantly different from the baseline value until 2 hours after bronchoalveolar lavage and became similar to the baseline value thereafter.

Conclusions: Transpulmonary thermodilution enabled to detect small short-term changes of indexed extravascular lung water secondary to bronchoalveolar lavage.