Utility of Lung Sonography in Acute Respiratory Failure

is explained by the physiopathology of pulmonary edema since fluids flow against gravity. On the other hand, in the BLUE protocol, allpatients had acute respiratoryfailure, and pulmonary edema nearly always correlated with the B profile. Errors in the final diagnosis, which can never be fully excluded, may explain the few cases (3%) in this study and a previous one- in which the B profile did not show. Exceptional cases of giant bullous dystrophy may alter the location of B lines. Lateral B lines were always sought in our series, but this information appeared to be redundant. Associated with the B profile, lateral B lines were redundant for diagnosingpulmonary edema. Associated with B, C, or AlBprofiles,lateral B lines were redundant for diagnosing pneumonia. Associated with the A profile, lateral B lineswere redundant with posterolateral alveolar! pleural syndrome (or PLAPS) for demonstrating pneumonia (seven cases). An A profile associatedwith lateral B lines should therefore be interpreted cautiously. It should be specified that the B lines are not a sign of "alveolar-interstitial" syndrome'! Our 1997 princeps study compared ultrasound mostly with radiologic alveolar-interstitial syndrome, but using CT scanning as the "gold standard" clearly demonstrated that B lines indicate interstitial syndrome, distinct from alveolarsyndrome.

Daniel Lichtenstein, MD. FCCP H~tal Amhrrnse-Pare Boulogne, Paris-Ouest. France Gilbert A Mezm, MD Centre Hospitalier Saint-Cloud, Paris-Ouest, France The authors have no conflictsof interest to disclose. Reproduction of thisarticleisprohibitedwithoutwrittenpermission from the American College of Chest Physicians (www.cliestjoumal. orWmisclreprints.shtml). Co~ to:Daniel A. Lichtenstein, MD, FCCP, Hospital Amhrrnse-Pare, Medical lCU, Rue Charles-de-Gaulle, BoulOgne, Paris-West, F-92100 France; e-mail: dlicht@jreefr DOl: lO.13181chest.08-2133 REFERENCES 1 Volpicelli G, Mussa A, Garofalo G, et al. Bedside lung ultrasoundin the assessmentof alveolar-interstitial syndrome. Am J Emerg Med 2006; 24:689-696 2 Volpicelli G, Caramello V, Cardinale L, et al. Bedside ultrasound of the lung for the monitoring of acute decompensated heart failure. Am J Emerg Med 2008; 26:585-591 3 Lichtenstein DA, Meziere GA. Relevanceof lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest 2008; 134:117-125 4 Lichtenstein 0, Meziere G. A lung ultrasound sign allowing bedsidedistinction between pulmonary edema and COPD: the comet-tail artifact. IntensiveCare Med 1998; 24:1331-1334

Utility of Lung Sonography in Acute Respiratory Failure To the Editor: I read with interest the article written by Drs. Lichtenstein and Meziere1 in a recent issue of CHEST (July 20(8) on the use of ultrasound to make a rapid diagnosis in patients with acute respiratoryfailurewith the BLUE protocol. In the "Materialsand Methods" section of the article, it is says that the ultrasound examination took no longer than 3 min. If the test was limited to just the evaluation of the lungs, one can believe that in experienced hands 3 min wouldbe sufficient.But goingby the protocol, 884

a patient with an A profile (ie, anterior predominant bilateral A lines with lung sliding) would require venous analysis. In my opinion, it is not possible to do venous analysis for deep vein thrombosis within 3 min, even if one is limiting the study to compression sonography.s In a patient with underlying chronic interstitial syndrome, it would be very difficult to differentiate acute exacerbationof the underlying disease from pulmonary edema; hence, the knowledge of a patient's medical history is crucial in such a situation." Pneumoniacan present with differentprofiles (A, anteriorpredominant bilateralA lines with lung sliding; AlB, anterior predominant B+ lines on one side and predominant A lines on the other side; C, anterior alveolarconsolidations; and BI, anterior predominant B+ lines with abolished lung sliding), which can make it confusing for clinicians especiallywhilethey are learning the use of lung sonography. I find lung sonography to be very useful in patients with conditionssuch as pulmonaryedema and pleural effusions, and in ruling out pneumothorax.w For other clinicalpresentations such as COPD, pneumonia, asthma, and pulmonary embolism. one may have to acquire extensive experience before becoming comfortable in interpreting the results. The authors excluded 41 patients from analysis (16 patients with an unknowndiagnosis, 16 with several final diagnoses, and 9 with a rare diagnosis). In clinicalpractice, these are the very patients who cause a diagnostic dilemma, in whom, besides a clinical examination and basic laboratory tests, clinicians would want to perform a diagnostic test with high accuracy. The yield of ultrasonography would decline if these patients were considered for statistical analysis,

Rahul Khosla, MD Veterans Affairs Medical Center Washington, DC The author has reported to the ACCP that no si~cant conflicts of interest existwith anycompanies/organizations whoseproducts or services max be discussed in this article. Reproduction of thisarticleisprohibitedwithoutwrittenpermission from the American College of Chest Physicians (www.cliestjoumal. orWmisclreprints.shtml). Correspondence to: Rahul Khosla, MD, Veterans Affairs Medical Center, Department of PulfTU}Tl(Jry & Critical Care Medicine, 50 lruing St Nw. Washington. DC 20422; e-mail: rkhosla8@ yahoo. com DOl: lO.13181chest.OS-1922 REFERENCES 1 Lichtenstein DA, Meziere GA. Relevanceof lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest 2008; 134:117-125 2 Kheir DE. One time comprehensive ultrasonography to diagnose deep vein thrombOsis: is that the solution. Ann Intern Med 2004; 140:1052-1053 3 Lichtenstein D, Meziere G, Biderman P, et al. The comet-tail artifact: an ultrasound sign of alveolar-interstitial syndrome. Am J Respir Crit Care Med 1997; 156:1640-1646 4 Beaulieu Y, Marik PE. Bedside ultrasonography in the ICU: part 1. Chest 2005; 128:881-895 5 Beaulieu Y, Marik PE. Bedside ultrasonography in the ICU: part 2. Chest 2005; 128:1766-1781

Response To the Editor: We thank Dr. Khosla for his thoughtful comments regarding our recent article in CHEST (July 2(08).1