randomized to therapy with vancomycin died than did patients randomized to therapy with linezolid. Therefore, we think that the conclusion that linezolid “is associated” with lower mor- tality rates and greater clinical success rates than vancomycin in patients with MRSA pneumonia is valid. We, as the nonemployee authors of these manuscripts, and many other clinicians who have been presented these data have raised the same concerns about subgroup analysis as have Powers and colleagues. Because of these concerns, Pharmacia (now Pfizer Inc) has sponsored a direct comparison of vanco- mycin and linezolid specifically in patients with MRSA venti- lator-associated pneumonia. Until this and possibly other studies are completed, we agree with Powers and colleagues that clinicians should exercise care in drawing conclusions based on subgroup analysis. We differ with them, however, in that we think that the analysis of the MRSA subgroup that we published is more pertinent to the clinical care of patients with MRSA pneumonia than the “clinically evaluable” and “micro- biologically evaluable” subgroup analyses of the entire cohort favored by Powers and colleagues. Richard G. Wunderink, MD, FCCP Northwestern University Feinberg School of Medicine Chicago, IL Marin Kollef, MD, FCCP Washington University School of Medicine St. Louis, MO Jordi Rello, MD University Rovira I Virgili Tarragona, Spain All three authors have received research support from Pharmacia and Pfizer Inc, and are consultants to Pfizer Inc. Reproduction of this article is prohibited without written permis- sion from the American College of Chest Physicians (e-mail: permissions@chestnet.org). Correspondence to: Richard G. Wunderink MD, FCCP, Pulmo- nary and Critical Care Division, Northwestern University Fein- berg School of Medicine, 676 St. Clair St, Suite 14 – 044, Chicago IL 60611; e-mail: r-wunderink@northwestern.edu References 1 Rubinstein E, Cammarata S, Oliphant T, et al. Linezolid (PNU-100766) versus vancomycin in the treatment of hospi- talized patients with nosocomial pneumonia: a randomized, double-blind, multicenter study. Clin Infect Dis 2001; 32: 402– 412 2 Bernard GR, Vincent JL, Laterre PF et al. Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med 2001; 344:699 –709 3 Wunderink RG, Rello J, Cammarata SK, et al. Linezolid vs vancomycin: analysis of two double-blind studies of patients with methicillin-resistant Staphylococcus aureus nosocomial pneumonia. Chest 2003; 124:1789 –1797 4 Wunderink RG, Cammarata SK, Oliphant TH, et al. Contin- uation of a randomized, double-blind, multicenter study of linezolid versus vancomycin in the treatment of patients with nosocomial pneumonia. Clin Ther 2003; 25:980 –992 5 Fagon J, Patrick H, Haas DW, et al. Treatment of gram- positive nosocomial pneumonia: prospective randomized comparison of quinupristin/dalfopristin versus vancomycin; Nosocomial Pneumonia Group. Am J Respir Crit Care Med 2000; 161:753–762 Nasal Airflow in Sleep-Disordered Breathing To the Editor: The excellent review by Rappai et al (December 2003) 1 of the nose and sleep-disordered breathing was timely and needed. Unfortunately, I think the authors did not clearly state the major reason why this subject remains unclear and controversial. Plainly stated, reliable, simple, reproducible clinical measurements of nasal airflow and nasal anatomy must be available before the role of nasal obstruction in sleep-disordered breathing can be defined. For the practicing clinician, the tests covered in the review, including peak nasal flow, rhinomanometry, and acoustic rhino- manometry, are generally not available, and their correlation with anatomic or dynamic obstruction has not been uniformly ac- cepted. There are two tests that did not receive attention in the review and should be considered when discussing nasal airway obstruction. The use of radiographic procedures, which was not chosen to Figure 1. This is an example of a symptomatic patient with fixed nasal inspiratory airflow obstruction on FINFVC. The forced inspiratory flow is 1.2 L/s. On the CT scan, the nasal passages demonstrate enlarged turbinates with narrowed nasal lumen. Reprinted with permission from Hooper. 2 316 Communications to the Editor