A pressure support system and method includes delivering a first flow of gas to the patient having first and second positive pressure levels that alternate with one another in a plurality of first cycles. The first flow of gas has a first period that is different than a predetermined apnea period. The method includes determining that the patient is experiencing an apneic episode, and, in response, delivering a second flow of gas to the patient. The second flow of gas has the first and second positive pressure levels that alternate with one another in a plurality of second cycles in the second flow of gas. The second flow of gas has a second period that is equal to the predetermined apnea period.
