A deficiency in airway nitric oxide (NO) could contribute to pulmonary vaso-occlusion in sickle cell disease (SCD). We measured the fractional expired concentration of NO (FENO) by chemiluminescence during a slow vital capacity maneuver against a positive pressure of 16 cm H2O at an expiratory flow rate of 50 mL/sec in 44 stable ambulatory adults with SCD and 30 healthy controls. A history of acute chest syndrome was present in 29 patients, and 22 complained of dyspnea. Mean ± SD FENO was significantly reduced in the SCD group compared with controls (14.8 ± 8.4 vs. 24.9 ± 13.5 ppb, P < 0.001). SCD patients with dyspnea had lower FENO than those without dyspnea (10.1 ± 5.7 vs. 19.6 ± 8 ppb, P < 0.001) and those with a history of ACS had lower values than those no episodes of ACS (13.0 ± 8.3 vs. 18.4 ± 7.6 ppb, P < 0.05). There was a weak correlation between FENO and percent-predicted DLCO (r = 0.4, P = 0.02) among the SCD patients. We conclude that exhaled NO is reduced in adults with SCD, and this may play a role in the pathogenesis of acute chest syndrome and chronic sickle cell lung disease.
- Acute chest syndrome
- Airway nitric oxide
- Chronic sickle cell lung disease
- Pulmonary hypertension
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