• Reduction in VAS Pain Score [ Time Frame: baseline, at 2,4,6 and 8 hours after start of drug and every 24 hours while therapy continues. ] [ Designated as safety issue: No ]
  

• Vital Signs [ Time Frame: At baseline, then every hour for the first 8 hours of therapy, followed by every 4 hours of therapy. ] [ Designated as safety issue: No ]
  
• Methemoglobin Levels [ Time Frame: at 2,4,6, and 8 hours after the start of therapy and then every 24 hours while on therapy. ] [ Designated as safety issue: Yes ]
  
• Need for analgesics [ Time Frame: baseline and throughout treatment. ] [ Designated as safety issue: No ]
  
• blood chemistry levels [ Time Frame: every 24 hours for the first 5 days after start of treatment. ] [ Designated as safety issue: No ]
  
• Lenght of hospitalization from admissions defined by the time of the discharge order is written [ Time Frame: study duration ] [ Designated as safety issue: No ]
  
• Rate of acute chest syndrome/pneumonia requiring blood transfusion [ Time Frame: study duration ] [ Designated as safety issue: No ]
  

The object of this study is to determine the safety and efficacy of nitric oxide for inhalation in the treatment of vaso-occlusive pain crisis (VOC) in patients with sickle cell disease. The study population will include patients with sickle cell disease (SS, S-beta-Thalassemia) presenting with vaso-occlusive pain crisis. Patients will be administered either placebo or inhaled nitric oxide to see if the experimental agent, inhaled nitric oxide, can reduce the time it takes for resolution of the vaso-occlusive crisis.

INCLUSION CRITERIA:

Each subject must meet all of the following inclusion criteria during the screening process in order to participate in the study:

• Patient must have a diagnosis of SCD (known SS, S-Beta-thalassemia or other hemoglobinopathies causing sickle cell disease). Patients with disease due to Hgb SC are not permitted.
• Must present to the ED/EC or other appropriate unit in VOC.
• Greater than or equal to 10 years old.
• Written informed consent/assent has been obtained.

EXCLUSION CRITERIA:

Subjects meeting any of the following criteria during baseline evaluation will be excluded from entry into the study:

• Exposure to therapeutic nitric oxide within the past 12 hours.
• Patient has received sildenafil or other phosphodiesterase 5 inhibitors, therapeutic L-arginine, nitroprusside or nitroglycerine within the past 12 hours.
• Patient has received previous ED/EC or other appropriate unit treatment for a vaso-occlusive crisis less than 48 hours or hospitalization less than 14 days ago (patients transferred directly from another ED or clinic may be enrolled).
• Patient has visited the ED/EC or other appropriate unit greater than 10 times in the past year having a vaso-occlusive crisis.
• Patients presenting with clinically diagnosed bacterial infection (e.g., osteomyelitis, pneumonia, sepsis or meningitis).
• Patients who are currently enrolled in any other investigational drug study except for hydroxyurea studies.
• Pregnant women (urine HCG + )/ nursing mothers.
• Patients who have received an exchange transfusion (not simple transfusion) in the last 30 days or are on a chronic simple or exchange transfusion program.
• Suspected splenic sequestration.
• Acute chest syndrome or pneumonia: Abnormal new pulmonary infiltrate (alveolar infiltration and not atelectasis) and one or more pulmonary signs and/or symptoms (fever, rales, wheezing, cough, shortness of breath, retractions).
• Previous participation in this study.