Blood Cell Count and the Presence or Absence of Infection in Venous Ulcers Treated With Platelet-Rich Plasma

Beatriz Guitton Renaud Baptista de Oliveira, DN, RN; Joyce Beatriz de Abreu Castro, MSN, RN; Bruna Maiara Ferreira Barreto Pires, RN, PhD; Márcia de Assunção Ferreira, DN, RN; Jane Marcy Neffá Pinto, PhD, MD; Lenise Arneiro Teixeira, DSC, BF


Wounds. 2021;33(5):113-118. 

In This Article

Materials and Methods

This case series study involved a sequential sample of 17 patients with venous ulcers treated with topically applied autologous PRP in combination with petrolatum gauze (ADAPTIC; 3M) and compression therapy. The follow-up time was 12 weeks. The study site was the outpatient wound repair clinic of a federal and university-affiliated public hospital in the state of Rio de Janeiro, Brazil. The data collection period was from August 2016 to December 2017. The research protocol complied with the Declaration of Helsinki, was approved by the research ethics committee of the university's faculty of medicine, and respected the principles established by the Ministry of Health of Brazil.

Before study participation, all participants provided informed consent; afterwards, the eligibility criteria (inclusion/exclusion) were assessed. The patients who met the inclusion criteria were subjected to an initial visit to start the treatment with PRP. The patients included in the study had not used PRP before.

Inclusion criteria consisted of the following: 18 years and older, without distinctions based on sex; a venous ulcer greater than 2 cm2 but less than 100 cm2; the presence of wounds with an evolution time of more than 12 weeks; hematocrit greater than 34%; hemoglobin greater than 11 g/dL; and platelet count greater than 150 000/mm3.

Exclusion criteria included the following: if the patient was pregnant or breastfeeding; alterations in prothrombin activation time or partial thromboplastin time; current use of corticosteroids; current immunosuppressive treatment or presence of an immunosuppressive disease; suspected malignancy of the ulcer; nonadherence to the proposed treatment plan; if the patient received a blood transfusion in the preceding 3 months; and presence of a circular ulcer.

All patients satisfied the inclusion criteria; there were no instances of discontinuation of treatment nor any treatment-related adverse events.

The patients included in the study were assessed by the dermatologist of the research team, and the patients had no indication for antibiotic therapy. The patients attended the outpatient clinic weekly for nursing consultation and dressing changes, with PRP application administered every 15 days.

Platelet-rich Plasma Dressing Application

Each wound was first irrigated with 0.9% saline. The dressing application of PRP on the wound bed created a thin layer (1 mm–2 mm).[14] After 5 minutes to 8 minutes, the wound was covered with dry sterile gauze; periwound hydration was kept with NDERM cream (Viemed). The dressing was fixed using cotton bands; compression therapy was the last layer of the bandage fixing.

Every 24 hours, the dressing was changed according to the home protocol. The wound was irrigated with 0.9% saline, dressed in sterile petrolatum gauze and ADAPTIC TOUCH Non-Adhering Silicone Dressing (3M), and supported by dry sterile gauze. The hydrating cream was used for periwound hydration once every 24 hours. The dressing was fixed using cotton bands and finished with compression therapy.

Mechanical debridement was performed only at the outpatient clinic, as necessary. All patients received kits containing dressing materials (ie, the sterile petrolatum gauze, nonadherent silicone dressing, sterile dry gauze, hydrating cream, cotton bands, and compression materials) in addition to written guidelines regarding daily dressing application at home.

Clinical specimens were collected a total of 3 times (once each on week 1, week 6, and week 12) by the nurses on the present research team by swabbing the venous ulcer using the quantitative swab culture and smear as described by Levine et al.[15]

For the microbial analyses, swabs were collected and added to Stuart transport medium, placed in 2.5 mL of sterile saline (0.9%), and then vortexed. Aliquots of approximately 0.5 mL were added to 2.0 mL of 2X tryptic soy broth (TSB), then incubated at 35°C (± 2°C) for 24 hours to 48 hours. After incubation, tubes showing a turbid culture medium were seeded on mannitol salt agar and cetrimide agar to determine the presence of Staphylococcus aureus and P aeruginosa, respectively. After incubating at 35°C (± 2°C) for 24 hours to 48 hours—ideal time for bacterial growth—the plates were analyzed for colony growth and characteristics. Saline and TSB samples were frozen in cryoprotective medium.

Suspected colonies were removed using an inoculation loop for identification by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (Microflex LT; Bruker Daltonics).

The McNemar test and χ2 test with a significance threshold of 5% were performed to evaluate infection improvement during the 12 weeks of treatment. Clinical signs of infection were identified using an outpatient wound protocol involving evaluation of the presence of pain, odor, purulent exudate, edema, erythema, and heat (Table 1). In accordance with the Infectious Diseases Society of America[16] guidelines for defining infection of diabetic wounds and wounds associated with other chronic diseases, the presence of infection in a wound was determined based on the presence of purulent exudate or 2 or more classic signs of inflammation (ie, heat, pain, erythema, and/or edema).

White blood cell counts were obtained during the screening visit and on the last day of the study (ie, before and after 12 weeks of treatment with autologous PRP). Minimum and maximum leukocyte counts of 4500/mm3 and 10 500/mm3, respectively, were used to define the normal range; these values were the reference values utilized at the institution where the study was performed.