5). Finally, we did not find any association related to the underlying disease process.Figure 4Bland-Altman analysis of agreement showing the differences between protein content (g/L) measurements plotted against the average between methods. Squares selleck chem Axitinib correspond to patients. The middle horizontal line indicates the average difference between the …Figure 5Bland-Altman analysis of agreement showing the differences between measurements of percentage of neutrophils plotted against the average between methods. Squares correspond to patients. The middle horizontal line indicates the average difference between …DiscussionThe sampling of alveolar fluid from patients with acute respiratory failure allows the study of lung inflammatory response to various injuries.
As demonstrated by Matthay and co-workers [4,5,10], direct sampling of undiluted lung oedema fluid may provide fundamental insights into the onset and evolution of acute inflammatory changes in permeability lung oedema as well as help to determine whether the pulmonary oedema is primarily from a hydrostatic or increased permeability mechanism. bBAL is generally well tolerated even in severely hypoxaemic patients with ALI/ARDS [15]. Yet, the sampling collections with this gold standard technique may sometimes be restricted by persistent severe hypoxaemia or cardiovascular instability, the presence of small endotracheal tubes or the unavailability of a bronchoscopist.
Mini-BAL has been successfully evaluated in comparison with bBAL for the diagnosis of ventilator-associated pneumonia [8], but it showed disappointing results in a recent study where both techniques were compared for assessing alveolar permeability and inflammation in patients at risk for ARDS or with ARDS [9]. However, considering that the s-Cath sampling might not perform adequately after 24 hours because the ability to obtain oedema fluid may decline over the course of ALI/ARDS, we decided to use the mini-BAL as a comparison methodology, because it is easily performed at the bedside and may be completed without a bronchoscopist.Mini-BAL was generally a safe procedure. However, when performed with a 16-Fr 5 mm outer diameter catheter, the mini-BAL procedure on rare occasions induced significant gas exchange abnormalities lasting up to 30 minutes after the end of collection, as shown by SpO2 and PaO2/FiO2abnormalities.
Hypoxaemia was probably induced by the lavage itself and by reduced tidal volumes delivered while the catheter was in place [7,16]. We measured the Ppeak on the ventilator (back pressure) before, during and after the procedure. This pressure significantly increased during mini-BAL sampling, representing an indirect sign of unstable tidal volumes during the ventilatory cycle [7,17]. Moreover, mini-BAL caused minor bronchial GSK-3 haemorrhage in five patients, leading us to stop the investigation prematurely.