Table 1.

PICOS Criteria

PICOS
Participants	Adult and pediatric patients with severe asthma refractory to conventional therapy
Intervention	Ketamine
Comparison	Placebo or other pharmacological strategies
Outcome	Improvement in oxygenation parameters; amelioration of clinical conditions; reduction of escalation to invasive ventilation; facilitation in weaning from mechanical ventilation; decrease in peak inspiratory pressures and increase in lung compliance; evaluation of side effects
Studies included	Randomized controlled trials; prospective studies for sensitivity analysis only