Ventilation and gas exchange during exercise in sickle cell anemia.

Adults with sickle cell anemia (SCA) have restrictive lung impairment, increased alveolar dead space, and hypoxemia. These factors, together with increased anaerobic metabolism, are thought to cause exercise hyperventilation. To assess the role of each of these in children, 34 patients with SCA and 16 control subjects performed pulmonary function and exercise tests. Twenty-eight patients with SCA had spirometric values and lung volumes, and all but two patients with SCA had arterial saturation greater than 91% during exercise. Despite a low VO2max (30.07 +/- 6.55 ml/min/kg), the ventilatory anaerobic threshold (VAT) in the patients occurred at a similar %VO2max as in the control subjects (69 +/- 9% versus 63 +/- 12%). The slope of the delta VE/delta VCO2 relationship for sub-VAT work was steeper in the patients (29.4 +/- 6.5 versus 24.7 +/- 5.2, p = 0.01), and the ventilatory equivalent for CO2 (VE/VCO2) in steady-state exercise was greater in the patients than in the control subjects (33.2 +/- 3.5 versus 30.8 +/- 3.5, p = 0.03). End-tidal PCO2 did not differ (38.3 +/- 3.0 versus 39.2 +/- 3.1), indicating equivalent alveolar ventilation. The patients had a higher dead space:tidal volume ratio (VD/VT) than did the control subjects (0.204 +/- 0.033 versus 0.173 +/- 0.024, p = 0.0005). The PaCO2 was significantly lower in those with lower Hb, but there was no difference in pH. In conclusion, children with SCA have an increased exercise ventilatory response caused in part by increased physiologic dead space, and in part by their low Hb. The greater dead space may be the result of sickle cells impairing capillary perfusion to ventilated alveoli.

[1]  W. N. Jensen,et al.  Arterial oxygen unsaturation in sickle cell disease. , 2015, The American review of respiratory disease.

[2]  J. Graziano,et al.  Cardiorespiratory response to exercise in patients with thalassemia major. , 1987, The American review of respiratory disease.

[3]  K. Wasserman,et al.  Coupling of Ventilation and CO2 Production during Exercise in Children , 1987, Pediatric Research.

[4]  H H Lipowsky,et al.  A model of microvascular oxygen transport in sickle cell disease. , 1985, Microvascular research.

[5]  W. Strong,et al.  Longitudinal exercise hemodynamics in children with sickle cell anemia. , 1984, American journal of diseases of children.

[6]  R. Bookchin,et al.  Effects of carbon dioxide and pH variations in vitro on blood respiratory functions, red blood cell volume, transmembrane pH gradients, and sickling in sickle cell anemia. , 1984, The Journal of laboratory and clinical medicine.

[7]  C. Poyart,et al.  Cardiorespiratory adjustments in chronic sickle cell anemia. , 1983, Bulletin europeen de physiopathologie respiratoire.

[8]  V. Edgerton,et al.  Characteristics of blood gas in response to iron treatment and exercise in iron-deficient and anemic subjects. , 1983, Journal of nutritional science and vitaminology.

[9]  P. Jones,et al.  Cardiac output as a controller of ventilation through changes in right ventricular load. , 1982, Journal of applied physiology: respiratory, environmental and exercise physiology.

[10]  B. Whipp,et al.  Effect of CO2 set point on ventilatory response to exercise. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[11]  O. Platt,et al.  Lung function in children with sickle cell anemia. , 1979, The American review of respiratory disease.

[12]  B. Hsi,et al.  Ventilatory functions of normal children and young adults--Mexican-American, white, and black. I. Spirometry. , 1979, The Journal of pediatrics.

[13]  D. Femi-pearse,et al.  Ventilatory response to carbon dioxide in patients with homozygous sickle-cell disease. , 1976, British journal of anaesthesia.

[14]  C. Davies,et al.  Iron-deficiency anaemia: its effect on maximum aerobic power and responses to exercise in African males aged 17-40 years. , 1973, Clinical science.

[15]  J. Cotes,et al.  Iron-deficiency anaemia: its effect on transfer factor for the lung (diffusiong capacity) and ventilation and cardiac frequency during sub-maximal exercise. , 1972, Clinical science.

[16]  S. B. Griffiths,et al.  Oxygen dissociation curves in sickle cell anemia and in subjects with the sickle cell trait. , 1955, The Journal of clinical investigation.

[17]  D. Orenstein,et al.  Exercise testing in children , 1988, Pediatric pulmonology.

[18]  A. King.  The Peripheral Arterial Chemoreceptors. , 1985 .

[19]  H. Andersen,et al.  Iron deficiency and muscular work performance. An evaluation of the cardio-respiratory function of iron deficient subjects with and without anaemia. , 1970, Scandinavian journal of clinical and laboratory investigation. Supplementum.