title: Severe nocturnal and postexercise hypoxia in children and adolescents with sickle cell disease.
abstract: Hypoxia is a common feature in children with sickle cell disease (SCD) that is inconsistently associated with painful crises and acute chest syndrome. To assess the prevalence and risk factors of hypoxia, we recorded daytime, nocturnal, and postexercise pulse oximetry (SpO2) values in 39 SCD patients with a median age of 10.8 years. Median daytime SpO2 was 97% (range, 89%-100%), and 36% of patients had daytime hypoxia defined as SpO2<96%. Median nocturnal SpO2 was 94.7% (range, 87.7%-99.5%), 50% of patients had nocturnal hypoxia defined as SpO2≤93%, and 11(37%) patients spent more than 10% of their total sleep time with SpO2<90%. Median postexercise SpO2 was 94% (range, 72%-100%) and 44.7% of patients had postexercise hypoxia defined as an SpO2 decrease ≥3% after a 6-minute walk test. Among patients with normal daytime SpO2, 35% had nocturnal and 42% postexercise hypoxia. Compared to 9 patients without daytime, nocturnal, or postexercise hypoxia, 25 patients with hypoxia under at least one of these three conditions had greater anemia severity (P = 0.01), lower HbF levels (P = 0.04), and higher aspartate aminotransferase levels (P = 0.03). Males predominated among patients with postexercise hypoxia (P = 0.004). Hypoxia correlated neither with painful crises nor with acute chest syndrome. Of 32 evaluable patients, 6 (18.8%) had a tricuspid regurgitation velocity ≥2.6 m/s, and this feature was associated with anemia (P = 0.044). Median percentage of the predicted distance covered during a 6-minute walk test was 86% [46-120]; the distance was negatively associated with LDH (P = 0.044) and with a past history of acute chest syndrome (P = 0.009). In conclusion, severe episodes of nocturnal and postexercise hypoxia are common in children with SCD, even those with normal daytime SpO2.
authors.affiliation: Pediatric Emergency Department, Hospital Necker, APHP, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Halphen
authors.affiliation: Paris Descartes University, Paris, France; Department of Biostatistics, Hospital Necker, APHP, Paris, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Elie
authors.affiliation: Pediatrics Department and Sickle Cell Clinic, Hospital Necker, AP-HP, Paris, France.
authors.forename: Valentine
authors.initials: V
authors.lastname: Brousse
authors.affiliation: Pediatric Pneumology and Allergology Department, Hospital Necker, APHP, Paris, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Le Bourgeois
authors.affiliation: Pediatrics Department and Sickle Cell Clinic, Hospital Necker, AP-HP, Paris, France.
authors.forename: Slimane
authors.initials: S
authors.lastname: Allali
authors.affiliation: Paris Descartes University, Paris, France; Pediatric Cardiology Department, M3C-Necker, AP-HP, Paris, Paris Descartes University, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Bonnet
authors.affiliation: Paris Descartes University, Paris, France; Pediatrics Department and Sickle Cell Clinic, Hospital Necker, AP-HP, Paris, France.
authors.forename: Mariane
authors.initials: M
authors.lastname: de Montalembert
mesh_terms: D056586:Acute Chest Syndrome / Q000150:complications; D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000150:complications*; D001775:Blood Circulation; D002648:Child; D002675:Child, Preschool; D015444:Exercise; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000150:complications* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D010092:Oximetry; D012129:Respiratory Function Tests; D013997:Time Factors; D014262:Tricuspid Valve Insufficiency / Q000150:complications