Incentive Spirometry and Breath Stacking

\- Postoperative pulmonary complications in patients undergoing cardiac surgery are a major clinical problem, presenting negative impact on morbidity, mortality , length of hospital stay and health care costs. Although physical therapy has been widely used as a resource to improve lung function in the postoperative period, the adoption of routine procedures of physical therapy needs be discussed. * Incentive spirometers are mechanical devices used to reduce postoperative pulmonary complications. In general, they are activated by an inspiratory effort, visualized by an uplifted plate or ball in a transparent cylinder during sustained inspiration. * Breath Stacking is a technique allowing the patient inhale a greater volume of air, kept for a longer period of time using a one-way valve, thus promoting the accumulation of successive inspiratory volume and preventing exhalation. * The objective of the study is to evaluate the effectiveness of two different techniques of respiratory therapy on both reducing postoperative pulmonary complications and improving lung function. * Type of study : randomized clinical trial * Hypothesis 1. Both techniques Trifllo II Incentive Spirometry ( IS) (Trifllo ® - II ) and Breath Stacking ( BS ) may present similar effectiveness on reducing pulmonary complications, improving lung function and respiratory muscle strength ( MIP and MEP), as well as reducing hospital stay . 2. Trifllo II Incentive Spirometry ( IS) (Trifllo ® - II ) may be more effective than Breath Stacking on reducing pulmonary complications, improving lung function and respiratory muscle strength, as well as reducing hospital stay.