Prospective evaluation of haemoglobin oxygen saturation at rest and after exercise in paediatric sickle cell disease patients

Abstract

Summary Low steady state haemoglobin oxygen saturation in patients with sickle cell anaemia has been associated with the degree of anaemia and haemolysis. How much pulmonary dysfunction contributes to low saturation is not clear. In a prospective study of children and adolescents with sickle cell disease aged 3–20 years at steady state and matched controls, 52% of 391 patients versus 24% of 63 controls had steady state oxygen saturation <99% (P < 0·0001), 9% of patients versus no controls had saturation <95% (P = 0·008) and 8% of patients versus no controls had exercise‐induced reduction in saturation ≥3%. Decreasing haemoglobin concentration (P ≤ 0·001) and increasing haemolysis (P ≤ 0·003) but not pulmonary function tests were independent predictors of both lower steady‐state saturation and exercise‐induced reduction in saturation. Neither history of stroke nor history of acute chest syndrome was significantly associated with lower steady‐state oxygen saturation or exercise‐induced reduction in saturation. Tricuspid regurgitation velocity was higher in patients with lower steady state haemoglobin oxygen saturation (P = 0·003) and with greater decline in oxygen saturation during the six‐minute walk (P = 0·022). In conclusion, lower haemoglobin oxygen saturation is independently associated with increasing degrees of anaemia and haemolysis but not pulmonary function abnormalities among children and adolescents with sickle cell disease.

Hematologic and hemorheological determinants of resting and exercise-induced hemoglobin oxygen desaturation in children with sickle cell disease

“…11 This is supported by the fact that hemoglobin oxygen desaturation induced by a six-minute walk is associated with higher tricuspid regurgitation velocities in SCD children. 6 Hemoglobin oxygen desaturation may be related to the rightward shift of the oxyhemoglobin dissociation curve due to the decreased affinity of sickle hemoglobin 12 which is caused by an increased content of erythrocyte 2,3-bisphosphoglycerate. 13 There is also growing evidence to suggest that hemoglobin oxygen desaturation at rest and EIHOD are independently associated with anemia 1,5,11,14 and hemolysis.…”

“…Cellular activation and abnormal vascular cell adhesion in SCD are caused by resting hemoglobin oxygen desaturation 8 which is associated with an increased risk for vaso-occlusive crises, 9 stroke 10 and elevated tricuspid regurgitation velocity, 6,7 suggesting a role for hemoglobin oxygen desaturation in the occurrence of these complications. 11 This is supported by the fact that hemoglobin oxygen desaturation induced by a six-minute walk is associated with higher tricuspid regurgitation velocities in SCD children.…”

“…13 There is also growing evidence to suggest that hemoglobin oxygen desaturation at rest and EIHOD are independently associated with anemia 1,5,11,14 and hemolysis. 1,5,6,11,14,15 It has been proposed that chronic hemolysis could promote pulmonary vasculopathy that could cause ventilation-perfusion mismatching and limit oxygen uptake by hemoglobin. 16 Intrinsic lung disease has been suggested to participate in hemoglobin oxygen desaturation at rest or EIHOD, but several studies have failed to detect such an association.…”

“…16 Intrinsic lung disease has been suggested to participate in hemoglobin oxygen desaturation at rest or EIHOD, but several studies have failed to detect such an association. 2,6,11 Sickle cell disease is characterized by severe hemorheological abnormalities that play a role in the pathophysiology of several acute and chronic complications. [16][17][18][19][20][21][22][23][24] Experimental work in non-SCD subjects and mathematical modeling strongly suggest that hemorheological impairment may contribute to hemoglobin oxygen desaturation at rest.…”

“…Hemoglobin oxygen desaturation at rest [1][2][3][4][5][6][7] and exerciseinduced hemoglobin oxygen desaturation (EIHOD) 6,7 are common in sickle cell disease (SCD). Cellular activation and abnormal vascular cell adhesion in SCD are caused by resting hemoglobin oxygen desaturation 8 which is associated with an increased risk for vaso-occlusive crises, 9 stroke 10 and elevated tricuspid regurgitation velocity, 6,7 suggesting a role for hemoglobin oxygen desaturation in the occurrence of these complications.…”