The study was performed to compare the effects of
negative-pressure wound therapy (NPWT) using gauze and foam on
wound edge movement and the macroscopic appearance of the heart and lungs after NPWT.
Sternotomy wounds were created in 6×70 kg pigs. Negative pressures of -40, -70, -120 and -160 mmHg were applied and the following were evaluated:
wound contraction, distension and the macroscopic appearance of the heart and lungs after NPWT.
Wound contraction was greater when using foam than gauze (3.5±0.3 cm and 1.3±0.2 cm, respectively, P<0.01). The application of
traction to the lateral edges of the
sternotomy resulted in greater
wound distention with foam than with gauze (5.3±0.3 cm and 3.6±0.2 cm, respectively, P<0.001). After using foam, the surface of the heart was red and mottled, and lung
emphysema and sometimes, lung
rupture were observed. After using gauze, the organ surface had no markings. The study shows that foam allows greater
wound contraction and distension than gauze. This movement of the
wound edges may cause damage to the underlying organs. There is less damage to the heart and lungs when using gauze than foam.