"Low cost, modified negative pressure wound therapy in infected orthopaedic wounds: can it be as effective as its costly counterparts?"

Evaluation of a new low-cost negative pressure wound therapy in the treatment of diabetic foot ulcers

OBJECTIVE

To investigate the effectiveness of a new and low-cost negative pressure wound therapy (LC-NPWT) in the treatment of diabetic foot ulcers (DFUs).

METHOD

In this retrospective cohort study, patients from our inpatient clinic with Wagner grade 3 DFUs were given LC-NPWT or conventional wound dressings. The primary outcome was the wound healing rates. Complete wound healing, defined as complete re-epithelialisation of the wound, was recorded during the two months of follow-up. The definition of complete epidermis of the wound was that the skin was closed (100% re-epithelialisation), with no drainage or dressing. The secondary outcomes were the number of inpatient days and surgical procedures, and outcomes after hospital discharge. The wound score from the Bates-Jensen wound assessment tool and the levels of the inflammation factors procalcitonin (PCT), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were compared between the two groups. The Kaplan-Meier survival estimate was used to examine the cumulative wound healing rate.

RESULTS

The study cohort comprised 41 patients. The two-month wound healing rate was higher in patients in the LC-NPWT group than in the control group (15/21 (71.4%) versus 8/20 (40.0%), respectively; p=0.043). At the end of the two-month follow-up period, the cumulative wound healing rate was higher in the LC-NPWT group than in the control group (p=0.032). Patients in the LC-NPWT group had fewer inpatient days (19.3±3.84 versus 25.05±4.81; p<0.001) and shorter duration of antibiotic use (32.14±3.89 days versus 36.10±5.80 days; p=0.014) than those who received conventional wound dressings. There were significant improvements in mean wound score between the LC-NPWT group and the control group (p<0.001). After one week of treatment, the blood levels of PCT (0.03±0.30ng/ml versus 0.07±0.08ng/ml; p=0.039), CRP (14.55±13.40mg/l versus 24.71±18.10mg/l; p=0.047) and ESR (42.05±29.29mm/h versus 61.65±22.42mm/h; p=0.021) were lower in patients who received LC-NPWT than those who received conventional wound dressings.

CONCLUSION

LC-NPWT is effective in the treatment of DFUs and provides a cheaper alternative for patients with DFUs that could potentially alleviate the economic distress these patients endure.

Device for Negative Pressure Wound Therapy in Low-Resource Regions: Open-Source Description and Bench Test Evaluation

Background: Negative (vacuum) pressure therapy promotes wound healing. However, commercially available devices are unaffordable to most potential users in low- and middle-income countries (LMICs), limiting access to many patients who could benefit from this treatment. This study aimed to design and test a cheap and easy-to-build negative pressure device and provide its detailed open-source description, thereby enabling free replication. Methods: the negative pressure device was built using off-the-shelf materials available via e-commerce and was based on a small pump, a pressure transducer, and the simplest Arduino controller with a digital display (total retail cost ≤ 75 US$). The device allows the user to set any therapeutic range of intermittent negative pressure and has two independent safety mechanisms. The performance of the low-cost device was carefully tested on the bench using a phantom wound, producing a realistic exudate flow rate. Results: the device generates the pressure patterns set by the user (25–175 mmHg of vacuum pressure, 0–60 min periods) and can drain exudate flows within the clinical range (up to 1 L/h). Conclusions: a novel, low-cost, easy-to-build negative pressure device for wound healing displays excellent technical performance. The open-source hardware description provided here, which allows for free replication and use in LMICs, will facilitate the application and wider utilization of this therapy to patients.