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

Disclosures

Wounds. 2021;33(5):113-118. 

In This Article

Abstract and Introduction

Abstract

Introduction: In general, chronic wounds are colonized by bacteria; however, when microorganisms start to multiply at higher levels, wounds can become infected, causing prolongation of the inflammatory phase and retardation of collagen synthesis and epithelialization.

Objective: The objective of this study was to evaluate the presence of infection in venous ulcers after 12 weeks of treatment with autologous platelet-rich plasma (PRP) and determine global white blood cell counts.

Materials and Methods: This case series study involved a sequential sample of 17 patients with venous ulcers treated with PRP for 12 weeks. Descriptive and inferential statistical analysis was performed using the McNemar test and χ 2 test.

Results: At baseline, 10 patients (58.8%) had wound infection. During the sixth week of treatment with PRP, only 3 patients (17.6%) continued to exhibit wound infection. After 12 weeks of PRP treatment, only 1 patient (5.9%) continued to exhibit wound infection. McNemar and χ 2 tests used to assess the presence of infection in the intervention group produced a P value of .0039 for a comparison of baseline and week 6 and a P value of .0078 for a comparison of baseline and week 12. These results demonstrated significant differences from baseline at both 6 weeks and 12 weeks of treatment, with greater significance at 12 weeks. There was no relationship between global white blood cell count and the presence of infection.

Conclusion: After intervention with PRP, 94% of patients experienced improvement concerning the infection of ulcers.

Introduction

Chronic wounds, defined as wounds that present with delayed healing, are considered to be a serious problem worldwide and are responsible for significant morbidity and mortality.[1] Also, these wounds have a considerable economic impact,[1] accounting for expenditures of approximately $25 billion per year in the United States.[2] The presence of wound infection is one of the factors responsible for increased medical expenses due to the resulting use of antimicrobial agents, hospitalization, and other complications.[2]

In general, chronic wounds are colonized by bacteria; however, low levels of such colonization do not delay the healing process because neutrophils, monocytes, lymphocytes, and macrophages increase as part of the physiological response, thereby increasing prostaglandin E2 levels and collagen formation.[3] However, when microorganisms start to multiply at higher levels, wounds can become infected, causing prolongation of the inflammatory phase and retardation of collagen synthesis and epithelialization, resulting in tissue damage.[3,4]

In addition to the classic signs of pain, edema, erythema, and heat, clinical signs and symptoms of infection in chronic lesions can also include the presence of serous exudate with simultaneous inflammation, delayed healing, discoloration in granulation tissue, friable granulation tissue, increased exudate level, odor, wound decompensation, increased pain, increased temperature in the perilesional area, erythema, and edema.[5]

One prominent challenge in wound treatment is the selection of an appropriate material for wound coverage. A potential catalyzing agent in the process of wound repair, platelet-rich plasma (PRP) has been presented as an innovation for promoting tissue regeneration and acceleration of the healing process.[6–9] In several case series, autologous PRP produced promising results in the treatment of chronic ulcers, both with and without comparison with conventional treatments;[10–12] all these studies recommended cost-benefit analyses and consideration of its accessibility, biocompatibility, safety, and efficacy.

To the authors' knowledge, few studies have evaluated the action of PRP on infected wounds. It is believed that white blood cells (WBCs) and innate immune defense peptides present in PRP may act as agents that decrease the proliferation of microorganisms. 13 On the other hand, the formation of fibrin due to the activation of the coagulation cascade and the presence of growth factors of PRP can favor microbial growth, especially of Pseudomonas aeruginosa 48 hours after its action on the wound.[13] However, it was not found in the literature how this microorganism uses growth factors in its cell replication process.

Further research with autologous PRP is needed to determine precise indications for clinical protocols and resolve questions regarding both the use of PRP and clinical signs of infection in a wound. The objectives of the current research were to evaluate the presence of infection in venous ulcers after 12 weeks of treatment with autologous PRP and determine WBC counts.

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