Please assess the completion status of the following clinical trial:

Trial Title: Dexmedetomidine Alleviates Postoperative Delirium After Brain Tumor Resections

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

Eligibility Criteria:
Inclusion Criteria:~* Patients undergoing selective frontotemporal tumor resection.~* Age ≥18 years.~* Obtain written informed consent.~Exclusion Criteria:~* Refusal to provide written informed consent.~* Preoperative severe cognitive impairment (mini-mental state examination, MMSE ≤ 20).~* Allergic to the study drug.~* History of psychotropic drugs within past 30 days.~* Pregnant or lactating women.~* History of traumatic brain injury or neurosurgery.~* Severe bradycardia (heart rate less than 40 beats per minute), sick sinus syndrome or second-to-third degree atrioventricular block.~* Severe hepatic or renal dysfunction.

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

Study Arms:
- DEX group (Type: ACTIVE_COMPARATOR): The DEX group will receives dexmedetomidine intraoperative.
- Placebo group (Type: PLACEBO_COMPARATOR): The placebo group will receives 0.9% saline intraoperative.

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