Please assess the completion status of the following clinical trial:

Trial Title: Substudy of Protocol 2019-002498-80 - NCT04223050: Comparing Mortality for Low Vs High Peripheral Oxygen Saturation in COPD-patients with Acute Exacerbation (O2flow-COPD)

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: NONE
- Phase: PHASE4
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* age 18 years or older~* ability to give informed consent~* previously diagnosed COPD (either confirmed diagnosis at prior hospital - contact or from their general practitioner or confirmed diagnosis by the treating physician in the emergency department (verified by use of relevant medication))~* admitted with acute exacerbation (acute and worsened shortness of breath) of COPD~* requiring oxygen treatment~Exclusion Criteria:~* Instability at arrival requiring immediate lifesaving treatment, e.g. intubation or non-invasive ventilation, within the first 30 minutes~* Expected total length of stay in hospital \< 12 hours~* Planned transfer to another hospital within 12 hours~* Unwilling to have repeated arterial blood gas analyses within the first 12 hours~* Patients judged terminal by treating physician in the emergency department~* Non-residents of the particular country~* Expected impossible follow-up~* Fertile women (\<50 years of age) with positive urine human gonadotropin (hCG) or plasma-hCG~* Prior participation in the study

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- High oxygen saturation (Type: ACTIVE_COMPARATOR): Peripheral oxygen saturation level \>94% Intervention: Drug: Oxygen gas
- Low oxygen saturation (Type: ACTIVE_COMPARATOR): Peripheral oxygen saturation level 88-92% Intervention: Drug: Oxygen gas

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