Please assess the completion status of the following clinical trial:

Trial Title: Oxygen Therapy in Cystic Fibrosis

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: NONE
- Phase: None
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* Children ≥ 6 years and adults ≥ 18 years with CF in a stable state~* With a forced expiratory volume in one second (FEV1) ≤ 50% of predicted value~* Having a pulse oximetry (SpO2) in room air ≤ 90% for ≥ 10% of the night and/or a SpO2 ≤ 90% for ≥ 10 minutes during the night~* Any patient with prior noninvasive positive pressure ventilation (NPPV) but who has stopped NPPV at least 15 days before the start of the study.~* Written approval by the patient and by the parents in case of a pediatric patient~* Patient having the French social security coverage~Exclusion Criteria:~* Patients with a respiratory exacerbation during the last 15 days~* Patients with NPPV or long term oxygen therapy prior to the start of the study and unable to stop this treatment~* Impossibility of a medical examination~* Pregnant patient or breastfeeding patient

- Gender: ALL
- Minimum Age: 6 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- Air - oxygen (Type: OTHER): One period in room air and one period with nocturnal oxygen therapy, separated by a wash out period of 2 to 6 weeks.
- Oxygen - Air (Type: OTHER): One period with nocturnal oxygen therapy and one period in room air, separated by a wash out period of 2 to 6 weeks.

Based on this trial design, predict the completion outcome and termination type (if applicable).