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Ventilation and gas exchange during exercise in sickle cell anemia
P Pianosi1, S J D'Souza, D W Esseltine
1Respiratory Medicine Service, McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada.
The American Review of Respiratory Disease
|February 1, 1991
Summary
Children with sickle cell anemia (SCA) show increased exercise ventilation due to higher physiological dead space and lower hemoglobin levels. This suggests sickle cells may impair lung perfusion, affecting breathing during physical activity.
Area of Science:
- Pediatric Pulmonology
- Hematology
- Exercise Physiology
Background:
- Adults with sickle cell anemia (SCA) experience lung issues like impaired function and hypoxemia, leading to exercise hyperventilation.
- The specific respiratory responses to exercise in children with SCA are not fully understood.
Purpose of the Study:
- To investigate the role of lung impairment, dead space, and hemoglobin levels in exercise hyperventilation in children with SCA.
- To compare the exercise ventilatory response in children with SCA to healthy controls.
Main Methods:
- Pulmonary function tests and exercise tests were conducted on 34 children with SCA and 16 healthy controls.
- Key metrics measured included VO2max, ventilatory anaerobic threshold (VAT), ventilatory equivalents, dead space:tidal volume ratio (VD/VT), and arterial blood gases.
Main Results:
- Children with SCA demonstrated a steeper delta VE/delta VCO2 slope and higher VE/VCO2 during steady-state exercise compared to controls.
- A significantly increased VD/VT ratio was observed in SCA patients.
- Lower hemoglobin levels correlated with lower PaCO2 in SCA patients.
Conclusions:
- Children with SCA exhibit an exaggerated ventilatory response during exercise.
- Increased physiological dead space and low hemoglobin are contributing factors to this hyperventilation.
- Impaired capillary perfusion by sickle cells may cause the increased dead space.