-When setting the ventilator, many of us use an initial tidal volume of 6 ml/kg -This number comes from ARDSnet data that demonstrated improved mortality with low tidal volumes in patients with ARDS/ALI -It is important to note that your calculation of 6 ml/kg is based upon IDEAL BODY WEIGHT (not total body weight) -For males: IBW = 50 kg + 2.3 kg for each inch over 5 feet. -For females: IBW = 45.5 kg + 2.3 kg for each inch over 5 feet.