The disclosure describes a method for automatically initiating ventilation, controlling ventilation, transitioning a ventilator to subject controlled ventilation, and weaning a subject from ventilation. The disclosure describes that the method for automatically initiating ventilation includes inputting a physical characteristic of the subject into a ventilator. The physical characteristic may be ideal body weight, height, or age. Based on the inputted physical characteristic, one or more ventilation parameters are calculated. The disclosure describes initiating ventilation based on the calculated parameters. During ventilation at least one physiological parameter of the subject is monitored. At least one ventilation parameter may be adjusted based on the monitoring of the physiological parameters and the inputted physical characteristic.