Pressure transduction to the thoracic cavity during topical negative pressure therapy of a sternotomy wound

Abstract

The present study was performed to examine pressure transduction to the thoracic cavity during topical negative pressure (TNP) therapy of a sternotomy wound. Seven pigs underwent median sternotomy. Pressure transduction catheters were placed on the anterior surface of the heart (under the foam), in the pericardium (under the heart), in the left pleura and in the oesophagus at the level of the heart. The wound was sealed as for TNP therapy. The vacuum source was set to deliver negative pressures between -50 and -200 mmHg. The pressure on the anterior surface of the heart changed in a linear relationship with the applied negative pressure and was slightly lower than the applied negative pressure (-102 +/- 9 mmHg at delivered -125 mmHg). Further down in the thoracic cavity, in the pericardium (under the heart), in the left pleura and in the oesophagus, the wound pressure was only slightly affected by TNP therapy. In conclusion during TNP therapy, negative pressure is effectively transmitted to anterior portions of the heart. This may explain our recent findings that TNP increases microvascular blood flow in the myocardium. The pressure difference between the anterior and the posterior portions of the heart causes the right ventricle to be sucked up towards the posterior parts of the sternum, where it might be exposed to the sharp edges of the sternal bone, which may result in heart injury.

Negative‐pressure wound therapy using gauze or open‐cell polyurethane foam: Similar early effects on pressure transduction and tissue contraction in an experimental porcine wound model

“…Previous publications have reported on the transmission of negative pressure to the wound bed. 12,14,15 Pressure transduction to the tissue from the vacuum source is dependent on adequate drainage tubes and a wound filler that is a material that does not inhibit pressure transduction. It has been shown that interface dressings influence the delivery of topical negativepressure therapy to the tissue.…”

“…12,14,15 Also, in complicated wounds, such as in the thoracic cavity, all spaces that are not in direct contact with the wound filler will not be reached by the negative pressure. 15 The wound model used in the current study is a superficial wound in which the entire wound bed has contact with the wound-filling material. This is presumably why the wound bed pressure was similar to the negative pressure set on the vacuum source pressure.…”

Influence on pressure transduction when using different drainage techniques and wound fillers (foam and gauze) for negative pressure wound therapy

“…The investigation complied with the ‘Guide for the Care and Use of Laboratory Animals' as recommended by the US National Institutes of Health and published by the National Academies Press (1996). Anesthesia and surgery were performed as described earlier (11).…”

Effects of Negative Pressure Wound Therapy on Healing of Open Wounds in Dogs

“…2,[17][18][19][20] NPWT was originally described for chronic wounds in people but applications for a variety of wounds and surgical situations are now reported, mainly in case series and clinical reviews. 21 The high rate of clinical success and relative ease of application of NPWT have encouraged adaptation in compromised flaps, [22][23][24][25] free skin grafts, [26][27][28][29] postoperative sternal incisional infection and mediastinitis, [30][31][32][33][34] perineal, urologic, and gynecologic wounds, 35,36 as well as for cytotoxic sloughs, 37 abdominal wall defects and drainage, [38][39][40][41] and burns. 42,43 Reduced overall treatment cost and shortened hospitalization have been documented with NPWT.…”