Comparative study of the microvascular blood flow in the intestinal wall during conventional negative pressure wound therapy and negative pressure wound therapy using paraffin gauze over the intestines in laparostomy

Higher closure rates of the open abdomen have been reported with negative pressure wound therapy (NPWT) than with other kinds of wound management. We have recently shown that NPWT decreases the blood flow in the intestinal wall, and that the blood flow could be restored by inserting a protective disc over the intestines. The aim of the present study was to investigate whether layers of Jelonet (TM) (Smith & Nephew) dressing (paraffin tulle gras dressing made from open weave gauze) over the intestines could protect the intestines from hypoperfusion. Midline incisions were made in ten pigs and were subjected to treatment with NPWT with and without four layers of Jelonet over the intestines. The microvascular blood flow was measured in the intestinal wall before and after the application of topical negative pressures of -50, -70 and -120 mmHg, using laser Doppler velocimetry. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced, to 61 +/- 7% (P < 0.001), after the application of -50 mmHg using conventional NPWT, and to 62 +/- 7% (P < 0.001) after the application of -50 mmHg with Jelonet dressings between the dressing and the intestines. The blood flow was significantly reduced, to 38 +/- 5% (P < 0.001), after the application of -70 mmHg, and to 42 +/- 6% (P < 0.001) after the application of -70 mmHg with Jelonet dressings. The blood flow was significantly reduced, to 34 +/- 9% (P < 0.001), after the application of -120 mmHg, and to 38 +/- 6% (P < 0.001) after the application of -120 mmHg with Jelonet dressings. The use of four layers of Jelonet over the intestines during NPWT did not prevent a decrease in microvascular blood flow in the intestinal wall.