title: Airways obstruction and pulmonary capillary blood volume in children with sickle cell disease.
abstract: Airways obstruction occurs in young children with sickle cell disease (SCD). Our aim was to test the hypothesis that increased pulmonary capillary blood volume at least in part explained the increased airways obstruction as this would inform which therapy might be most appropriate to treat the airway obstruction.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Twenty-five SCD children and 25 ethnic origin matched controls were recruited.
  
  
  METHODS
  Respiratory system resistance, using impulse oscillometry at 5 Hz (R5 %pred), pulmonary capillary blood volume (Vc), alveolar volume (VA), and spirometry were assessed before and after bronchodilator (ipratropium bromide). Lung volume measurements were also made.
  
  
  RESULTS
  The SCD children compared to the controls had a higher R5 %pred before (median 133 (range 88-181)% vs. 102 (83-184)%, P = 0.0046) and after (105 (79-150)% vs. 91 (64-147)%, P = 0.0489) bronchodilator and their median Vc/VA (ml/L) was higher before (26 (18-38) vs. 18 (14-28) P < 0.0001) and after (26 (19-41) vs. 18 (13-27) P < 0.0001) bronchodilator. There were similar decreases in R5 %pred post-bronchodilator in the two groups, but no significant changes in Vc/VA in either group. Vc/VA correlated significantly with R5 %pred in the SCD children only.
  
  
  CONCLUSIONS
  Increased pulmonary capillary blood volume contributes to the increased airways obstruction in children with SCD, hence, bronchodilators may be of limited benefit in reducing their airways obstruction.
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, SE5 9RS, United Kingdom.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Wedderburn
authors.forename: David
authors.initials: D
authors.lastname: Rees
authors.forename: Susan
authors.initials: S
authors.lastname: Height
authors.forename: Moira
authors.initials: M
authors.lastname: Dick
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
authors.forename: Alan
authors.initials: A
authors.lastname: Lunt
authors.forename: Anne
authors.initials: A
authors.lastname: Greenough
mesh_terms: D000293:Adolescent; D000402:Airway Obstruction / Q000209:etiology* / Q000503:physiopathology; D000755:Anemia, Sickle Cell / Q000503:physiopathology*; D001810:Blood Volume / Q000187:drug effects; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000494:pharmacology; D002196:Capillaries / Q000187:drug effects / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008168:Lung / Q000098:blood supply* / Q000187:drug effects / Q000503:physiopathology; D008176:Lung Volume Measurements; D008297:Male; D009991:Oscillometry; D013147:Spirometry; D014797:Vital Capacity / Q000187:drug effects
chemical_list: D001993:Bronchodilator Agents
keywords: anemia; impulse oscillometry; lung function