Bt 3000 plus

Urinary cotinine was measured in accordance with the procedures described by Cattaneo et al.²⁴ A high-performance liquid chromatograph (1290 Infinity; Agilent^®, Santa Clara, CA, USA) equipped with a Zorbax Eclipse XDB-C8 (4.6 mm × 150 mm × 5 µm) column and a UV-Vis (λ = 260 nm) detector (Agilent^®) was used, with an injection volume of 20 µL and an isocratic mobile phase flow rate of 0.4 mL/min. The methodology was validated by using the parameters set forth in Brazilian National Health Oversight Agency Resolution no. 899.²⁵ Because of its sensitivity and specificity, high-performance liquid chromatography is recommended for measuring cotinine; in addition to being less expensive than other methods, high-performance liquid chromatography allows determination of low concentrations of cotinine.²⁶ The limits of detection and quantification were 6.46 µg/L and 19.59 µg/L, respectively.
Urinary cotinine levels are directly related to biological factors such as renal function, urine flow, and urine pH. For increased accuracy, urinary cotinine levels were adjusted for urinary creatinine levels (urinary cotinine/creatinine ratio, in µg/g).²⁷Urinary creatinine was measured with a creatinine assay kit and a spectrophotometer with a thermostated cuvette at 37°C (readings at 30 s and 90 s; wavelength, 510 ηm). An automated chemistry analyzer (BT 3000 PLUS; Wiener lab Group, Rosario, Argentina) was used.

After approval of the project by the Institution Review Board, under number 804.216, serum CRP was measured prospectively and for convenience in 103 patients submitted to primary TKA between September 2014 and March 2015.
The study included all patients who underwent primary TKA and accepted to participate by signing an informed consent form. Patients undergoing revision arthroplasty and those with inflammatory diseases were excluded.
On the day before surgery, the first sample of 2 mL of venous blood was collected to determine the preoperative quantitative CRP (CRP₀); assessment was made in the laboratory of the institution. The biochemistry analyzer BT3000 Plus® (Wiener Lab, Rosario, Santa Fe, Argentina) was used for the analysis with the turbidimetric method, whose reference values in adults is 5 mg/L for infectious diseases. Patients had their stature and body weight measured. Weight was documented in kilograms and height in meters. These data were used to calculate the body mass index (BMI) of each patient in order to categorize them according to the parameters of the World Health Organization (WHO).¹²
The same implant was used in all cases (PFC Sigma® DePuy Synthes) and the posteriorly stabilized model with patellar replacement was chosen. Intramedullary guides were used for the femoral cut and extramedullary guides for the tibial cut. Patients were operated with the use of perioperative ischemia; the cuff was applied at the thigh level, with a pressure 100 mm/Hg above the systolic pressure.
Pre-anesthetic assessment, filed in the medical record, was used to document the underlying pathologies and the clinical status of the patients.
On the third day after the arthroplasty, while patients were still hospitalized, blood collection procedure for serum CRP was repeated (CRP₃).
Patients were discharged according to clinical criteria, and an outpatient follow-up appointment was scheduled for the 21st day after surgery. At the follow-up appointment, before consultation or any manipulation of the surgical wound, a blood sample was collected for the third CRP measurement (CRP₂₁).
A spreadsheet containing patients’ initials, medical record number, age, gender, skin color, primary knee pathology, laterality, clinical comorbidities, body weight and height, BMI, and CRP₀, CRP₃, and CRP₂₁ values was created.
From the data collected, two files were created and then analyzed using SPSS (Statistical Package for the Social Sciences), version 22.0, and Microsoft Excel 2007.
Descriptive analysis was presented as tables of the observed data, expressed as mean, standard deviation, median, and minimum and maximum for numerical data, and frequency (n) and percentage (%) for categorical data, as well as illustrative graphs. CRP₂₁ was considered normalized when it reached a value lower than or equal to 5 mg/L or lower than or equal to CRP₀.
In the inferential analysis, to verify the association between qualitative variables, chi-squared test was used; when inconclusive, Fisher's exact test was applied. For quantitative variables, the normality hypothesis was verified by the Kolmogorov–Smirnov and Shapiro–Wilk tests. When distribution was normal, comparison between the two groups was made by Student's t-test, otherwise, the nonparametric Mann–Whitney test was used. Comparison between more than two independent groups was conducted using the Kruskal–Wallis test. The quantitative variables were analyzed by two approaches: by calculating Pearson's linear correlation coefficient for normal distributions and Spearman's correlation coefficient for non-normal. A 5% significance level was adopted for rejecting the null hypothesis.