RESUMO
Background: It is important to encourage lung inflation to prevent postsurgical pulmonary complications and we compared three breathing techniques that place different emphasis on inspiratory flow and breath-holding. Methods: Fourteen healthy older people (69 ± 3.6 yrs) used diaphragmatic breathing (DB), Triflo II (TF), and a water pressure threshold device (BreatheMAX; BM) in a randomized and balanced crossover design. Outcome measures were inspiratory flow and pressure, inspiratory time (Ti), tidal volume (Vt), and breathing frequency. Results: Inspiratory flow with TF was significantly faster than DB and BM (p < 0.001: 0.96 ± 0.1; 0.43 ± 0.20 and 0.28 ± 0.1 L.s-1, respectively) and pressures greater (p < 0.001: -1.3 ± 0.6, -5.5 ± 1.2 and -2.8 ± 3.6 cm H2O). However, Ti was shorter (TF, 1.16 ± 0.21s; DB, 3.31 ± 0.97 s, p < 0.001; BM, 5.53 ± 1.92 s, p < 0.001), resulting in smaller Vt (TF, 1.12 ± 0.29 L; DB, 1.28 ± 0.29L, p = 0.003; BM, 1.37 ± 0.43L, p = 0.016). Breathing frequency was faster with TF compared to DB and BM (p < 0.001). Conclusions: Substantial lung inflation could be achieved with any of the above-mentioned methods, although Vt was smaller with TF and the high inspiratory flow with this method may not inflate the lower lung. The high pressures and rapid breathing with TF could increase the sense of effort. Trials are needed to determine the clinical value of the different breathing exercises.
