1. Field of the Invention
Embodiments of the invention relate to fluid (e.g., liquid) delivery to a wound therapy dressing and more particularly relate to systems and methods for automated fluid delivery to a negative pressure wound therapy dressing.
2. Description of the Related Art
Existing fluid delivery systems for wound therapy dressings are typically based on infusion systems. It is worth noting that with drug delivery systems, the user is responsible for determining the dosage of the fluids and would not generally use an automated system to determine the desired volume of liquid that should be delivered.
However, if one considers the art with respect to fluid delivery for wound dressings, such an approach may not be appropriate. For example, wound dressing fluid delivery systems are not delivering intravenous drugs. Furthermore, wounds are not uniform and indeed will change volume as the therapy progresses. Consequently, using techniques employed in other areas to prescribe a dose volume may result in under- or over-delivery of fluids with the commensurate problems. In existing delivery systems, fluid pressure may be monitored to determine if there is a line blockage, but it is typically not monitored to determine the pressure of the fluid at the site of delivery.
The referenced shortcomings are not intended to be exhaustive, but rather are among many that tend to impair the effectiveness of previously known techniques in fluid delivery to wound dressings; however, those mentioned here are sufficient to demonstrate that the methodologies appearing in the art have not been satisfactory and that a significant need exists for the techniques described and claimed in this disclosure. Instillation of fluid as an adjunct to negative pressure wound therapy (NPWT) is currently accomplished by asking the user to specify an instillation time (gravity feed systems) or instillation volume (active pumping systems).
Because it is difficult to judge the volume of a dressed wound, either approach can be problematic and time-consuming to arrive at the desired fill volume. A “Fill Assist” approach has also been used, which requires the user to stop metered fluid flow based on visual observation of the wound filling; whereafter, the automated system dispenses the same volume in subsequent instillation cycles.
However, even this simplified approach requires that the user be attentive to stopping the flow, and can easily lead to over-filling the wound, waste of NPWT collection canister volume, and potentially instillation fluid leakage at the dressing. It is therefore desirable that automated systems and methods be developed to allow the user to determine when the wound dressing has received the proper volume of liquid for instillation.