The pig: a model for human infectious diseases

A bandage has a first sheet overlying a wound and located adjacent to it and a top sheet overlying the first sheet. The first sheet has a plurality of discrete passageways overlying the wound and adapted to communicate negative pressure established by a negative pressure source to the wound.

Wound treatment apparatus

A wound therapy combination comprising a suction head and a surgical drape. The suction head comprises a planar flange portion and a tubular connector piece on a first face that communicates with an aperture extending to a second face. The second face is formed with projections that define flow channels for facilitating flow of liquids to the aperture.

Surgical drape and suction head for wound treatment

The invention relates to a portable wound treatment apparatus for stimulating the healing of superficial wounds. The apparatus comprises a housing (210) containing a suction pump and a canister for containing fluids drawn from the wound. The housing is supported on a harness or belt (216, 218) worn by the patient and is connected to a porous dressing at the wound site by a catheter.

Portable wound treatment apparatus

Apparatus for the application of topical negative pressure therapy to a wound site is described, the apparatus comprising: a wound contacting element for retaining wound exudate fluid therein; a wound covering element that provides a substantially airtight seal over the wound contacting element and wound site; a vacuum connection tube connecting a wound cavity to a vacuum source; and a vacuum source connected to a distal end of the vacuum connection tube.

Vacuum assisted wound dressing

In this article a dressing system is described that is capable of providing continuous or intermittent wound irrigation. It is based on a felt dressing provided with an adhesive cover and ports for fluid supply and suction drainage. At continuous irrigation (approximate rate, 70 ml/h), a 1-L fluid bag and a siphon about 30 cm in height are used; at intermittent irrigation (approximate rate, 60 ml/min), a 60-ml fluid bag and a suction balloon are used. In an experimental set-up it was shown that the supplied fluid diffused throughout the dressing felt and that the felt was partly saturated both during continuous and after intermittent irrigation, the effect of gravity being counteracted by capillary force and suction. The suction pressure at the drainage port and within the occlusively applied felt showed a linear relationship. The drainage of particles, while relatively impeded at low flow rates, was satisfactory at rates recommended for clinical use. The dressing felt was inert to adherence of bacteria and white blood cells. This dressing system would seem to provide access to the whole wound surface for active therapy through fluid supply and suction drainage.

A dressing system providing fluid supply and suction drainage used for continuous or intermittent irrigation.

Full-thickness excision wounds infected with Staphylococcus hyicus, a pig pathogen, or Staphylococcus aureus, a human pathogen, were produced in pigs. The inoculated wounds were kept occluded for 2 days and then exposed and biopsied at intervals for 9 to 12 days. The exposed lesions were edematous and exudative. The S. aureus model was experimentally advantageous because the infection remained localized to the wound without systemic infection or signs of discomfort. The S. hyicus infection caused a rash with skin blisters; thus, its use is discouraged. The concentration of S. hyicus in the wound on day 2 was log 8.6 +/- 0.4 CFU/g (mean +/- standard deviation). On day 4 the mean was log 9.2. For S. aureus the values were log 8.0 +/- 0.9 on day 2 and 6.9 on day 4 (p less than 0.05). Of the 50 individual values in the S. aureus series, 45 were above log 5. The inflammatory reaction was more pronounced after the infection with S. hyicus, whereas with S. aureus the fibroblast response came earlier and was more pronounced. The model parallels typical clinical courses of staphylococcal infection.

Staphylococcal wound infection in the pig: Part I. Course.

Bacteria from full-thickness excision wounds with staphylococcal infection in the pig were cultured quantitatively. The bacterial concentration increased with the size of the inoculum, and after 2 days it had already reached a stable, maximal level of approximately log 8 CFU/g in the tissue. The correlation coefficient was 0.753 in comparing concentrations from superficial and deep biopsy halves and 0.145 from "surface wash" and superficial biopsies. The "within wound" sample distribution was logarithmic. The gain in precision when assessing the mean bacterial concentration from three instead of one biopsy was 45%. The coefficient of variation of between wound and within wound determinations was in the same range (i.e., 7.1-12.5%). Paired observations from a sample population with 7 sites (wounds) were needed to determine a 10% change in the bacterial concentration at a significance level of p less than 0.05, and a similar change could be determined from unpaired observations based on two populations with eleven sites.

Sandén G

Papers

A dressing system providing fluid supply and suction drainage used for continuous or intermittent irrigation.

Staphylococcal wound infection in the pig: Part I. Course.

Staphylococcal wound infection in the pig: Part II. Inoculation, quantification of bacteria, and reproducibility.