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Daniel Lichtenstein, MD, FCCP; Gilbert A. Mezière, MD
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Affiliations: Hôpital Ambroise-Paré Boulogne, Paris-Ouest, France,  Centre Hospitalier Saint-Cloud, Paris-Ouest, France

Correspondence to: Daniel A. Lichtenstein, MD, FCCP, Hospital Ambroise-Paré, Medical ICU, Rue Charles-de-Gaulle, Boulogne, Paris-West, F-92100 France; e-mail: dlicht@free.fr


The authors have no conflicts of interest to disclose.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).


Chest. 2009;135(3):884-885. doi:10.1378/chest.08-2734
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Published online

We thank Dr. Khosla for his thoughtful comments regarding our recent article in CHEST (July 2008).1

This duration may appear to be short. The BLUE protocol was performed by experienced operators it is true, but this was done with the aim of not interfering with the management that was underway. Doctors integrating the BLUE protocol in patient management are free to take more time. Several points explain our data, however. Since 1992, we have labeled our whole-body approach “fast-echo” because using no Doppler device, only one microconvex probe, and one setting provides major savings of time. Since the lung is superficial and has extensive contact with the wall, no time is lost searching for lung windows. A lines and B lines, are simple signs that can be detected immediately. Highlighting characteristic profiles (B, B′, A/B, and C, 46% of cases) shortens the BLUE protocol, since it exempts these patients from venous and lateroposterior lung analysis. Only the A profile (54% of cases) requires venous investigation. Exclusive use of a transversal venous approach, dynamic maneuvers (before compression) that immediately pinpoint the location of the vessels, and other time-saving points are explained in the book General Ultrasound in the Critically Ill.2

The B profile is generated by hemodynamic pulmonary edema, rarely pneumonia, and exceptionally chronic interstitial disease (CID). Diagnosing edema complicating CID (an even more exceptional event) is a limitation of the BLUE protocol if it is used alone. Integrating the patient's history of CID and echocardiography showing left heart anomalies favors associated edema (see Rare Diagnosis section). Note that when the BLUE protocol indicates non-B profiles, left heart analysis is not relevant, since edema is unlikely.

The BLUE protocol uses three dichotomous items. The diagnosis of pneumonia may appear complex, simply because it uses several profiles. The key points to seek are as follows: asymmetry (left/right in the A/B profile; anterior/posterior in the A/posterolateral alveolar/pleural syndrome [PLAPS] profile); focalized disorders (C profile); and specific combinations (B′ profile).

The principle of the BLUE protocol, which is designed to provide one profile, yielding one ultrasound diagnosis, subsequently correlated with one final diagnosis, which we retained as the “gold standard,” is to prioritize items. For this methodological reason, patients with no or several diagnoses were purposely excluded from the study (n = 41). However, all patients had a precise profile.

Patients Without a Diagnosis

The profiles indicated pneumonia in seven cases, edema in six cases, and COPD/asthma in three cases. In these precise cases, the BLUE protocol adds new information to the traditional approach. It is logical to extrapolate that such patients will benefit from this information.

Patients With Two Diagnoses

The B profile was seen in nine patients with edema plus pneumonia, and in two patients with edema plus COPD; the C profile was seen in one patient with edema plus pneumonia; the A/PLAPS profile was seen in one patient with edema plus COPD, one patient with edema plus phrenic paralysis, and one patient with pneumonia plus laryngeal dyspnea; and the A/PLAPS profile plus venous thrombosis was seen in one patient with pneumonia plus embolism. Therefore, the BLUE protocol established one of the two diagnoses in 87.5% of cases.

Rare Diagnoses

These are the very patients (9 of 269 cases [see Table 1 in our article1]) that may have slightly modified the value of the BLUE protocol. We stress that rare diagnoses are not necessarily difficult diagnoses. Patients with massive pleural effusion can be managed without the BLUE protocol. Rare diagnoses were excluded in order to simplify our algorithm. We remind readers that the BLUE protocol aimed to validate an ultrasound approach the value of which is to be associated with the usual initial data. This synthesis provides accurate diagnoses in nearly all cases, decreasing the need for CT scanning.

When rare or double diagnoses are suspected by the usual initial approach, the BLUE protocol can be enriched with other data (eg, unpublished lung ultrasound signs or echocardiography findings). This extended BLUE protocol would increase the potential of the ultrasound, although to the detriment of simplicity.

Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008;134:117-125. [PubMed] [CrossRef]
 
Lichtenstein D. General ultrasound in the critically ill. 2005; Berlin, Germany Springer-Verlag:70-95
 

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References

Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008;134:117-125. [PubMed] [CrossRef]
 
Lichtenstein D. General ultrasound in the critically ill. 2005; Berlin, Germany Springer-Verlag:70-95
 
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