© 2008 American Thoracic Society
Questions on the Reversibility of Lung Collapse in Early Acute ARDSFrom the Authors:We thank Dr. Guerin for his letter. Regarding the first question, Table 1 of our article (1) shows the data at admission, collected in the intensive care unit before transportation of the patients to computed tomography (CT) and before starting the study protocol. Therefore, the compliance values shown in this table are different from the baseline compliance values described in Table 3 and Figure 1, which refer to the moment of the first CT acquisition at protocol start. The different positive end-expiratory pressure values of 10 and 5 cm H2O, respectively, confirm these different conditions. We agree that the use of the term baseline for both conditions is confusing, and we apologize for the lack of clarity that led to this misinterpretation. Regarding the second and third questions, the aim of this study was to investigate the physiological effects of a new recruitment strategy aimed at full lung recruitment and not to evaluate mortality. Patients were submitted to a specific protocol that lasted 4 hours. Before and after performing the protocol, patients were routinely managed by the attending physician in an uncontrolled way. This is essentially different from a controlled trial. Finally, the admission characteristics of the patients in this study indicate that very sick patients with an expected high mortality were included. We fully agree that no conclusions can be drawn from these results, as Dr. Guerin stated. We show the impressive physiological results obtained in a very sick patient, who unfortunately died as his critical illness continued. We believe that saving the lives of these patients is not a matter of the fate of one representative patient but rather of advancing our knowledge of the complex pathophysiology of ventilation-induced lung injury and the effects of lung-protective ventilation strategies. Only by better understanding the mechanisms (2) involved in these phenomena will it be possible to acquire the necessary knowledge to improve management protocols that will hopefully result in positive trials (3–5) for such patients. The positive physiological effects of lung recruitment were clearly shown in our study. Future studies incorporating this knowledge will be necessary to show whether the proposed strategy can decrease mortality by reducing ventilator-associated lung injury and consequent multiple organ failure.
University of São Paulo FOOTNOTES Conflict of Interest Statement: The author does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
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