title: Pressure transduction and fluid evacuation during conventional negative pressure wound therapy of the open abdomen and NPWT using a protective disc over the intestines.
abstract: BACKGROUND
  Negative pressure wound therapy (NPWT) has gained acceptance among surgeons, for the treatment of open abdomen, since very high closure rates have been reported with this method, compared to other kinds of wound management for the open abdomen. However, the method has occasionally been associated with increased development of fistulae. We have previously shown that NPWT induces ischemia in the underlying small intestines close to the vacuum source, and that a protective disc placed between the intestines and the vacuum source prevents the induction of ischemia. In this study we compare pressure transduction and fluid evacuation of the open abdomen with conventional NPWT and NPWT with a protective disc.
  
  
  METHODS
  Six pigs underwent midline incision and the application of conventional NPWT and NPWT with a protective disc between the intestines and the vacuum source. The pressure transduction was measured centrally beneath the dressing, and at the anterior abdominal wall, before and after the application of topical negative pressures of -50, -70 and -120 mmHg. The drainage of fluid from the abdomen was measured, with and without the protective disc.
  
  
  RESULTS
  Abdominal drainage was significantly better (p < 0. 001) using NPWT with the protective disc at -120 mmHg (439 ± 25 ml vs. 239 ± 31 ml), at -70 mmHg (341 ± 27 ml vs. 166 ± 9 ml) and at -50 mmHg (350 ± 50 ml vs. 151 ± 21 ml) than with conventional NPWT. The pressure transduction was more even at all pressure levels using NPWT with the protective disc than with conventional NPWT.
  
  
  CONCLUSIONS
  The drainage of the open abdomen was significantly more effective when using NWPT with the protective disc than with conventional NWPT. This is believed to be due to the more even and effective pressure transduction in the open abdomen using a protective disc in combination with NPWT.
authors.affiliation: Department of Cardiothoracic Surgery, Lund University Hospital, SE-221 85 Lund, Sweden. sandra.lindstedt@skane.se
authors.forename: Sandra
authors.initials: S
authors.lastname: Lindstedt
authors.forename: Malin
authors.initials: M
authors.lastname: Malmsjö
authors.forename: Johan
authors.initials: J
authors.lastname: Hansson
authors.forename: Joanna
authors.initials: J
authors.lastname: Hlebowicz
authors.forename: Richard
authors.initials: R
authors.lastname: Ingemansson
mesh_terms: D058107:Abdominal Wound Closure Techniques / Q000009:adverse effects / Q000295:instrumentation*; D000818:Animals; D004322:Drainage; D005260:Female; D007421:Intestine, Small / Q000098:blood supply; D007431:Intraoperative Complications / Q000517:prevention & control; D007511:Ischemia / Q000209:etiology / Q000517:prevention & control; D008297:Male; D054843:Negative-Pressure Wound Therapy / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D011312:Pressure; D034421:Sus scrofa