title: Factors associated with dyspnea in adult patients with sickle cell disease.
abstract: OBJECTIVE
  The aim of this prospective study was to determine the cardiorespiratory factors associated with dyspnea in patients with sickle cell SS-hemoglobin disease, with a specific interest in lung vascular involvement.
  
  
  METHODS
  Forty-nine patients (29 women and 20 men; mean [+/- SD] age: women, 29 +/- 6 years; men, 31 +/- 11 years) underwent direct evaluations (Borg scale evaluation during a 6-min walk test) and indirect evaluations (modified Medical Research Council [MRC]score) of their dyspnea, pulmonary function tests (PFTs) [spirometry, volumes, diffusing capacity of the lung for carbon monoxide (Dlco), diffusing capacity of the alveolar-capillary membrane, and pulmonary capillary blood volume measurements], echocardiography, and biological evaluation.
  
  
  RESULTS
  Thirty-four patients complained of significant breathlessness (MRC score, > 1). Indirect and direct evaluations of dyspnea were correlated. PFT results depicted a very mild restrictive pattern (mean total pulmonary capacity, 86 +/- 11% predicted) and an impairment of Dlco (mean Dlco corrected for the degree of anemia, 69 +/- 13% predicted). The statistical analysis demonstrated that dyspnea and exercise performance were closely linked to indexes of Dlco but not with any echocardiographic or biological measure including anemia. Nevertheless, only approximately 25% of the variability was explained by these associations. Despite having a similar history of vasoocclusive crisis events, women had more severe anemia, dyspnea, decreases in Dlco (corrected for the degree of anemia), and a higher capillary blood volume (corrected for alveolar volume) than men.
  
  
  CONCLUSIONS
  Lung vascular disease contributes to dyspnea and the exercise limitation of patients with sickle cell disease. A sequential assessment of Dlco would therefore constitute one of the objective functional end points for follow-up studies of these patients.
authors.affiliation: Service de Physiologie, Hôpital Henri Mondor, Assistance Publique-Hôpitaux de Paris, Créteil, France. christophe.delclaux@egp.aphp.fr
authors.forename: Christophe
authors.initials: C
authors.lastname: Delclaux
authors.forename: Françoise
authors.initials: F
authors.lastname: Zerah-Lancner
authors.forename: Dora
authors.initials: D
authors.lastname: Bachir
authors.forename: Anoosha
authors.initials: A
authors.lastname: Habibi
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Monin
authors.forename: Bertrand
authors.initials: B
authors.lastname: Godeau
authors.forename: Frédéric
authors.initials: F
authors.lastname: Galacteros
mesh_terms: D000328:Adult; D000755:Anemia, Sickle Cell / Q000453:epidemiology* / Q000503:physiopathology; D001944:Breath Tests; D004417:Dyspnea / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000378:metabolism; D011653:Pulmonary Diffusing Capacity; D012129:Respiratory Function Tests
chemical_list: D009569:Nitric Oxide