Risk Factors for Pressure Ulcers

Primary outcomes

1. Anthropometric characteristics

   Time frame: one hour

   Body Mass Index (BMI) is a simple index of weight-for-height. It is defined as the weight in kilograms divided by the square of the height in metres (kg/m2).

2. Diabetes mellitus

   Time frame: one hour

   • Plasma levels glucose in mmol/l was measured by standard enzymatic methods using reagents in a fully automated analyzer Cx5 Pro-Bechman Coulter-Fuller-Ton

3. Dyslipidemia

   Time frame: one hour

   • Lipid markers: total serum cholesterol (CH), serum triglyceride, serum HDL- CH, in mmol/l, levels were measured by standard enzymatic methods using reagents in a fully automated analyzer (Randox Antrim, UK; CX9-BECKMANN).
   • Low density lipoprotein cholesterol (LDL-C) in mmol / l was determined by Friedewald formula.
   • non esterified fatty acids in serum was determined by colorimetric method at 550 nm (mmol/l)

4. Renal failure

   Time frame: one hour

   • renal profile: urea (mmol/l), creatinine and uric acid (μmol/l) levels were measured by standard enzymatic methods using reagents in a fully automated analyzer ( Cx9 Pro-Bechman Coulter-Fuller-Ton).

5. Inflammatory parameter

   Time frame: one hour

   • C-reactive protein (CRP), in mg/l, was measured using immunoturbidimetric methods (COBAS INTEGRA 400 Roche).

6. Endogenous inflammatory marker

   Time frame: one hour

   • α1-acid glycoprotein, in g/l, measured using the dry chemistry method (BN prospec, siemens)

7. Markers of nutritional status

   Time frame: one hour

   • albumin (chronic marker) and prealbumin (early marker) were measured, in g/l, using the dry chemistry method (BN prospec, siemens).
   • Protide in g/l was measured by standard enzymatic methods using reagents in a fully automated analyzer (CX9-BECKMANN).

8. Marker of lipid peroxidation

   Time frame: one day

   • Serum total homocysteine concentrations in μmol/l were measured by using an AxSYM (ABBOTT) homocysteine assay.
   • thiobarbituric acid reactive substances (TBARS) in serum was determined by the fluorimetric method of Yagi in μmol/l.

9. Antioxidant parameters

   Time frame: one day

   • Serum catalase activity in KU/l was determined according to the spectrophotometric method of Goth .

10. Total antioxidant status

    Time frame: one hour

    Serum total antioxidant status in mmol/l was measured with RANDOX kit (Cat. No. NZ 2332; Randox Labs Ltd., Crumlin, UK) by colorimetric method at 600 nm .

11. Determination of trace elements

    Time frame: one hour

    Serum copper in μmol/l was indicated spectrophotometrically with RANDOX kit (Cat. No. CU 2340; Randox Labs Ltd., Crumlin, UK) at 580 nm according.

    Serum zinc was measured in μmol/l with RANDOX kit (Cat. No. ZN 2341; Randox Labs Ltd, Crumlin, UK) at 560 nm.

12. Nutritional status

    Time frame: 3 hours

    • Nutritional Risk Index (NRI) was originally derived from the serum albumin concentration and the ratio of present to usual weight [NRI = (1.489 x albumin, g/L) + (41.7 x present weight/ideal body weight)] and categorized as follows: severe risk (NRI < 83.5), moderate risk (83.5 < NRI < 97.5) and no risk (NRI > 97.5).

13. Nutritional risk

    Time frame: 3 hours

    • Prognostic Inflammatory and Nutritional Index (PINI) is a simple clinical [PINI = AAG x CRP / albumine x prealbumin] and classificated as follows: normal (1<PINI score <10), mild malnutrition (11<PINI score<20), severe malnutrition (21<PINI score<30) and risk for death when PINI score >30.

    These scores gained in popularity as it uses an objective rather than subjective measurements to determine nutritional risk in hospitalized patient populations.

14. A microbiological diagnosis

    Time frame: 3 days

    The bacterial colonization of a wound is a recognized detrimental factor in the multifactorial process of wound healing.

    wound per patient suffering from pressure ulcer was cultured by swab to determine the bacterial species of the infection and helps guide antibiotic therapy.

    The representative sample is collected before topical or systemic antibiotics are initiated and pain assessment should be conducted prior to wound procedures such as dressing changes and debridement. Bacterial swabs provide information on the predominant flora.

15. Proteomics

    Time frame: 2 days

    • Serum gelatinase activities of MMP-9 by zymography (%)

16. DNA extraction

    Time frame: 2 days

    Genomic DNA was extracted from whole blood using the salting out method for the part of molecular biology.

17. Genotype for the MMP9-1562 C/T polymorphism

    Time frame: 1 days

    • Genetic polymorphism in the MMP9 coding region 1562C>T was screened following the polymerase chain reaction and restriction fragment length polymorphism (RFLP-PCR).
    • The frequency distributions of different MMP9-1562 C/T genotypes and allele were investigated.
    • The relationship between the polymorphism of the MMP-9 gene and the severity of PU was analyzed.

18. Genotyping of TNF- α G238A

    Time frame: 1 days

    • TNF-α G238A promoter polymorphism were determined by the RFLP-PCR method.
    • The genotypic and allelic frequencies of -238G/A were calculated
    • This study investigated the association between TNF-α-238G>A and Pressure ulcer in Tunisian population.

19. Genotyping of TNF- α G308A

    Time frame: 1 days

    • The genotypic analysis of the TNF-α G308A polymorphism was performed using Allele-specific PCR (AS-PCR) amplification.
    • In this study, we have analyzed the TNF-α gene promoter -308G/A polymorphism in Tunisian patients with PU to evaluate the contribution of this SNP in genetic susceptibility to PU.