Effects of the breath stacking technique after upper abdominal surgery: a randomized clinical trial

Objective: To evaluate the effect of the association of the breath stacking (BS) technique associated with routine physiotherapy on pulmonary function, lung volumes, maximum respiratory pressures, vital signs, peripheral oxygenation, thoracoabdominal mobility, and pain in the surgical incision in patients submitted to upper abdominal surgery during the postoperative period, as well as to analyze BS safety. Methods: This was a randomized clinical trial involving 34 patients divided into a control group (CG; n = 16), who underwent conventional physiotherapy only, and the BS group (BSG; n = 18), who underwent conventional physiotherapy and BS. Both groups performed two daily sessions from postoperative day 2 until hospital discharge. The primary outcomes were FVC and Vt. The safety of BS was assessed by the incidence of gastrointestinal, hemodynamic, and respiratory repercussions. Results: Although FVC significantly increased at hospital discharge in both groups, the effect was greater on the BSG. Significant increases in FEV1, FEV1/FVC ratio, PEF, and FEF25-75% occurred only in the BSG. There were also significant increases in Ve and Vt in the BSG, but not when compared with the CG values at discharge. MIP and MEP significantly increased in both groups, with a greater effect on the BSG. There was a significant decrease in RR, as well as a significant increase in SpO(2) only in the BSG. SpO(2) acutely increased after BS; however, no changes were observed in the degree of dyspnea, vital signs, or signs of respiratory distress, and no gastrointestinal and hemodynamic repercussions were observed. Conclusions: BS has proven to be safe and effective for recovering pulmonary function; improving lung volumes, maximum respiratory pressures, and peripheral oxygenation; and reducing respiratory work during the postoperative period after upper abdominal surgery.