Some patients with sickle cell disease may show oxygen desaturation during exercise.
Exercise-induced oxygen desaturation is associated with reduced 6MWT.
Factors impacting exercise-induced oxygen desaturation (may require blood rheology studies):
(1) decreased RBC deformability
(2) hemoglobin F percentage (impacts RBC deformability)
(3) RBC disaggregation threshold (greater strength of blood cell aggregates)
(4) rate of hemolysis
Parameters:
(1) percutaneous oxygen saturation at rest in percent
(2) percutaneous oxygen saturation after exercise in percent
oxygen desaturation associated with exercise =
= (oxygen saturation at rest) - (oxygen saturation after exercise)
Interpretation:
• Different thresholds may be used to define desaturation.
• A value >= 3% after the 6MWT may be used.
• It is important to evaluate the resting oxygen saturation since some patients show a lower oxygen saturation at rest, with further drop during exercise.
