Nebulized Ketamine Plus Standard Care vs. Standard Care Alone in Moderate to Severe Asthma Exacerbations

\*\*Intervention Description:\*\* Nebulized ketamine is administered as a single dose of 0.5 mg/kg of ketamine hydrochloride diluted in 0.9% normal saline to a total volume of 5ml. The solution is delivered via a standard jet nebulizer over approximately 15-20minutes. This intervention is given once at the time of enrollment in the emergency department, in addition to standard asthma care. The ketamine used is in injectable solution form (typically 50 mg/mL concentration), drawn and diluted immediately prior to nebulization. Participants are monitored continuously for 60 minutes after administration to assess changes in peak expiratory flow rate (PEFR), symptom relief, and adverse events. The goal is to evaluate the bronchodilatory effect and safety of nebulized ketamine in adults with moderate to severe asthma exacerbation who present to the emergency department.

\*\*Intervention Description (Control Group):\*\* Participants in the control group will receive a single nebulized dose of 5 mL of 0.9% normal saline, delivered using a standard jet nebulizer over approximately 10-15 minutes. This placebo intervention is administered once at the time of enrollment in the emergency department, after standard asthma care. Standard care includes repeated doses of nebulized salbutamol and ipratropium, systemic corticosteroids (oral or intravenous), and supplemental oxygen as needed. The placebo solution is identical in appearance and volume to the active ketamine solution used in the intervention group to maintain blinding. All participants will be monitored for 60 minutes after nebulization to assess changes in peak expiratory flow rate (PEFR), symptom relief using a visual analog scale (VAS), and the occurrence of any adverse events.