Biochemical Markers with Predictive Value in Polytrauma Patients with Femoral Fractures

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1 Biochemical Markers with Predictive Value in Polytrauma Patients with Femoral Fractures DORIANA LUPESCU¹, MARIA GREABU², ALEXANDRA TOTAN², MIHAIL NAGEA³, GHEORGHE ION POPESCU 4, OLIVERA LUPESCU 4 *, ALEXANDRU LISIAS DIMITRIU 4, IRINA STOIAN 5, IOANA MARINA GRINTESCU 6, DAN CORNECI 7 ¹Maria Burghele Hospital, Anaesthesia and Intensive Care Unit, 5 Studioului Str., 70000, Buftea, Romania ²University of Medicine and Pharmacy Carol Davila, Biochemistry Department, Dental Medicine, 37 Dionisie Lupu Str., , Bucharest, Romania ³Orthopaedics and Traumatology Clinic, Clinical Emergency Hospital, 8 Calea Floreasca, , Bucharest, Romania 4 University of Medicine and Pharmacy Carol Davila, Orthopaedics and Trauma Clinic, Clinical Emergency Hospital, 37 Dionisie Lupu Str., , Bucharest, Romania 5 University of Medicine and Pharmacy Carol Davila, Biochemistry Department, General Medicine, 37 Dionisie Lupu Str., , Bucharest, Romania 6 University of Medicine and Pharmacy Carol Davila, Anaesthesia and Intensive Care, Clinical Emergency Hospital, 37 Dionisie Lupu Str., , Bucharest, Romania 7 University of Medicine and Pharmacy Carol Davila, Anaesthesia and Intensive Care, Elias Universitary Hospital, 37 Dionisie Lupu Str., ,Bucharest, Romania Polytrauma represents one of the most challenging aspects of modern medicine, due to its high mortality and morbidity, affecting especially young, active patients. Therefore, research is nowadays directed towards optimising the treatment for these patients, which is extremely difficult, as polytrauma is characterized by a complicated pathophysiology with intricate pathways, potentially generating local and general complications and requiring a multidisciplinary approach. An essential issue for these patients is a careful monitoring algorithm, able to determine an appropriate therapeutic response in due time, so objective, measurable and reproducible elements able to do this have been sought. Since biochemical markers have these properties, and the most important pathogenic element in polytrauma is the Systemic Inflammatory Response Syndrome (SIRS), the authors of this paper evaluate the predictive value of inflammatory markers in order to improve the monitoring algorithm of these patients. The results of this prospective study demonstrate some statistically significant correlations, such as those between lactate (at admission and 24 hours later) and mortality, as well as between IL-6 and early systemic complications, which are of great value because they can concentrate the efforts of the multidisciplinary team and save the life of the poytrauma patient. Keywords: polytrauma, IL-6, inflammatory response, damage control Polytrauma is characterized by the existence of multiple injuries, at least one of them having lethal potential, and an Injury Severity Score (ISS) more than 16. The ISS is based on the Abbreviated Injury Scores (AIS), and ISS represents the sum of the square values of AIS in the most severely damaged parts of the body. ISS = AIS (a) 2 + AIS(b) 2 + AIS(c) 2 [1] Although several other definitions were taken into consideration, as there is no consensus yet, the pathophysiology of polytrauma is unanimously described as being ruled by the fragile balance between the inflammatory and counter-inflammatory phenomena. Any trauma determines a complex neuro-endocrine reaction due to bleeding and painful stimuli, and this is called a Systemic Post Aggressive Reaction (SPAR). In polytrauma, multiple SPARs are generated by the initial injuries, and by their treatment as well, and these isolated reactions generate a global one not by a summative effect, but by enhancing each other, thus generating what is called Systemic Inflammatory Response Syndrome (SIRS)[2]. Its severity is difficult to be quantified, several markers being proposed for this purpose [3]. Opposing to SIRS, antiinflammatory mechanisms produce a systemic action called Compensatory, Anti-inflammatory Response Syndrome (CARS) and the balance between them is crucial for the outcome of the patient. The biochemical profile of SIRS is complex and the most important components are: Acute Phase Proteins (APP), Cytokines, Phospholipids, Acute Traumatic Coagulopathy and the Complement System. I. Acute Phase Proteins (APP) - the most important ones are the following: - CRP (C Reactive Protein) has 5 components, with 206 aminoacids each; with a Molecular Weight (MW) of 115kDa; it is produced especially by the liver and lungs; several cytokines (IL-6, TNF-α, IL-1) initiate its liver synthesis, as reaction to infection, inflammation or tissue injuries. CRP increases in trauma, influences the Complement System, opsonisation and phagocytosis. [4,5] - Procalcitonin (PCT) consist of 116 aminoacids and belongs to the so-called group of calcitonin gene-related peptides. It is produced by the C-cells of the thyroid gland, and has an unclear biological function. Normal values are bellow 0.5 ng/ml and they increase in sepsis and after stimulation by endotoxins and pro-inflammatory cytokines (TNF-α, IL-1β); the PCT value can increase up to 1000 times by non-hormone non-thyroid stimulation; it is currently accepted that levels higher than 2 ng/ml are predictive of sepsis [6]. The half time of PCT is h; it can rise h after trauma, and then, if the outcome is favourable, it rapidly decreases. Some authors describe a peak on day 7, after which it goes back to normal by day * olivera_lupescu@yahoo.com REV.CHIM.(Bucharest) 69 No

2 30 [7]. If sepsis or other systemic complications appear, either the levels remain high or a secondary peak appears [8,9]. As for the specificity for a certain type of complication, PCT is considered to be more specific then CRP and IL-6 for the differential diagnosis between SIRS and sepsis in critically ill patients. Fibrinogen, also a good parameter for inflammation, septic or aseptic II. Cytokines - which are significant in the: a.acute phase: Tumor Necrosis Factor alpha (TNFα) and Interleukin 1 beta (IL-1β) -Tumor Necrosis Factor alpha (TNFα) is expressed on the surface of the macrophages, lymphocytes and other cells involved in inflammation; it rapidly rises immediately after trauma, with a short half-life, and then slowly decreases. It has been demonstrated to have a strong negative predictive value for ARDS [10] and it acts through the following mechanisms: -it increases capillary permeability [11] and has a procoagulant activity, -it activates the NK lymphocytes and the macrophages and enhances the synthesis of arachidonic acid and proinflammatory markers : IL-6, IL-8, IL-10, IFN γ -Citotoxicity and Cytokine TH1 production [12-13] -Interleukin 1 beta (IL-1β), produced by the endothelial cells and monocytes activated by ischaemia or infection, has a pro-inflammatory effect, increasing the capillary permeability and the action of lymphocytes and macrophages, as well as the endothelial adherence and the chemotaxis of neutrophils. The level of IL-1β in the pulmonary alveoli correlates with hypoxemia and the risk of ARDS (Acute Respiratory Distress Syndrome) [14-15]. b.subacute phase : -The most important is Interleukin 6 (IL-6), which has both pro- and anti-inflammatory properties; it is produced by most of the cells involved in trauma response (such as endothelial cells, monocytes, macrophages, B and T lymphocytes). Studies have demonstrated that the levels of IL-6 correlate with ISS, MODS, ARDS or sepsis, and with the patients outcome as well [16]. IL-6 stimulates the activation and multiplication of B and T lymphocytes, induces liver synthesis of APP (CRP, fibrinogen, Complement system, antitrypsin), and enhances the activity of NK lymphocytes as well as the differentiation of Cytotoxic T lymphocytes [17-19]. The normal value of the IL-6 is under 5.9 pg/ml and in trauma it rises rapidly within the first 24 h, getting back to normal within 5-7 days in the absence of complications [20] c.secondary phase: IL-12, IL-18 It must be underlined that cytokines are involved in both SIRS and CARS, as some of them have dual action [21] III. Phospholipids - the most important are: PGI2 (vasodilator and inhibitor of the platelet aggregation) and TXA2 (vasoconstrictor and stimulator of the platelet aggregation) IV. Post-traumatic coagulopathy V. Complement System Treatment of polytrauma patients with femoral shaft fractures is based on the idea that these are fractures with a major systemic impact; due to bleeding ( ml), it is unanimously accepted that urgent stabilization of these fractures is considered a resuscitative method; the type of stabilization depends on the status of the patient, which is described as: stable, borderline, unstable and in extremis according to several clinical and paraclinical criteria established by a multidisciplinary evaluation. In stable patients, Early Total Care (ETC) can be performed, using intramedullary nails, while a minimal invasive stabilization using and external fixator (ExFix) is indicated in borderline and unstable patients, method which is called Damage Control [22-24]. The rationale for this attitude is the concept of the Second Hit after the initial trauma (called the First Hit), a systemic reaction mainly based on inflammation occurs. Any internal or external condition interfere in this period can re-trigger an even more powerful inflammatory mechanism, therefore a new SIRS, which can considerably affect the stability, already compromised, of the polytrauma patient, leading to systemic complications ( ARDS, MSOF or even death). This type of condition is called second hit and it must avoid by any mean especially in polytrauma patients, therefore all the therapeutic interventions will be performed so as not to overwhelm the reactive capacity of the patient, as Damage Control achieves in unstable and borderline patients [25-27]. Despite all the efforts of modern medicine, these patients still have a high mortality and morbidity and their outcome is impacted by a high rate of systemic complications, the most severe being ARDS (Acute Respiratory Distress Syndrome), MSOF ( Multiple System Organ Failure) and finally, death. The main pathological pathway of these complications is represented by SIRS, which is why the purpose of this study is to evaluate the predictive value of some inflammatory markers in polytrauma patients, so as to allow an early detection of complications and to generate a proper therapeutic response. Experimental part Material and methods The authors present the results of a prospective transversal study, including 148 polytrauma patients with femoral fractures, operated in the Clinical Emergency Hospital Bucharest between , with proper medical records; the fractures were closed or open type I or II, those with type III fractures being excluded, as were the patients with multiple injuries but not polytrauma, those with isolated femoral fractures or with incomplete medical data The study group was analysed according to several type of criteria, from which, relevant for this paper, are d.demographical (age, sex) e.initial status (stable, borderline, unstable and in extremis), f.treatment of the femoral fracture ( initial stabilisation) g.the incidence of general complications h.the biochemical profile, including: leucocytes, thrombocytes, ESR, serum lactate, CRP, IL-1, and IL-6, evaluated in a dynamic manner, so as to establish relevant markers for the outcome of the patients. Statistical analysis was performed using the SPSS 20 (Statistical Package for the Social Sciences) system, the descriptive analysis and the chi-squared test (the value for statistical significance of the test being p < 0.005). The ANOVA method and the Bonferonni test were used in order to test different correlations, as well as the ROC (Receiver Operating Characteristics), and the AUC (Area under Curve), reflecting the efficiency of a model through its sensitivity and specificity Results and discussions According to the collected data, the demographical analysis showed that most of the patients were young, active (fig. 1a), thus explaining the high social impact of this problem. Using the clinical and paraclinical parameters, the patients were described as (fig. 1b): REV.CHIM.(Bucharest) 69 No

3 Fig.1. Demographical analysis (a) and the stability of the patients (b) - haemodinamically stable (96 patients), for whom intramedullary nails were used (Early Total Care ETC) - borderline and unstable (52 patients), for whom an ExFix was used as a Damage Control (DC) method (fig. 1b). The general complications in the study group were represented by: - ARDS-14.18% (21/148 patients) - MSOF-9.46% (14/148 patients), - other systemic complications -10.8% (thromboembolic and abdominal) (16/148 patients) -death- 8.1 % (12/148 patients) In order to evaluate the predictive value of different biochemical markers, the patients were divided into three groups: - patients who survived without complications (Group I) (82 patients) - patients who survived with systemic complications (MSOF, ARDS) (Group II) (54 patients) - patents who died (Group III- 12 patients), and for each group, the dynamic of certain parameters was described The first parameter was ESR (fig. 2a), for which the curves demonstrated: -Increasing values up to day 6, then progressive decrease to normal, for Group I -Continuously increasing values up to day 7,followed by a slow decrease for the patients in Group II, so that normal values were described late, after day 21, due to systemic complications -Continuously increasing values in Group III, where death occurred within a fully installed inflammatory syndrome. Although, there was no statistically significant correlation between the value of ESR and mortality (p=0.38) or incidence of complications (p= 0.22), thus demonstrating the relatively low value of ESR for predicting complications in polytrauma patients. The curve of the leucocytes (fig. 2b) is somehow different from that of ESR, with no concordance between its aspect and the outcome of the patients. As seen in Figure 2b, the value of leucocytes decrease in Group II, despite the onset of complications, while in Group III, there is a minor enhancing just before death occurred. Form a statistical point of view, no correlation was identified between the initial and the 24 h level of leucocytes and mortality or the incidence of complications, therefore we can conclude that the leucocytes does not represent an optimal monitoring parameter, meaning that an increased value may suggest the probability of a complication, but a descendent curve does not necessarily mean a favourable outcome. Another parameter which was tested was PCR, which, as represented in figure 3a, shows to be correlated to the outcome of the patients, as following: -According to the classical description of the inflammatory syndrome, the PCR value increases up to day 6 -In Group III, there is a continuous increase of the CRP values, correlated with the lethal complications, unlike the initial decrease of the leucocytes in the same group -In Group II, CRP initially decreased up to day 6, then the curve is ascendant, with the second peak coexisting with the moment of complications; statistical analysis showed that 92% of the patients had increased values of CRP in day 14, which was statistically significant (p=0.0018) The analysis of thrombocytes (fig. 3b) in the three groups was also performed, as thrombocytes represent one of the criteria used for classifying the patients in stable, borderline or unstable, and correlated with the Acute Traumatic Coagulopathy (ATC). Statistical analysis demonstrated the following: -No statistically significant correlation was identified between the incidence of complications and the value of the thrombocytes at admission and after 24 h ( p=0.08), but between the incidence of complications and the value of thrombocytes in day 14. -The initial value of thrombocytes was not correlated with mortality (p=0.32), thus suggesting that the complex features of ATC are dependent on far more complex elements than the number of the thrombocytes. Fig.2. The value of ESR (a) and leucocytes (b) in the study group REV.CHIM.(Bucharest) 69 No

4 Fig.3.The value of CRP (a) and thrombocytes (b) in the study group The values of the seric lactate, those at admission and those after 24 h were statistically correlated (p=0.0012) with mortality (fig. 4); as for the data revealed by the ROC, the AUC for lactate was 0.87, and the value of 3.5 mmol/l was detected as having a sensitivity of 87% (95% CI= ) and specificity of 84% (95%CI= %) to be correlated with mortality. In Groups I and II (patients who survived), the lactate varied between mmol/l, with a median value of 2.5 mmol/l, while in Group III ( patients who died), the values were , with a median of 4.8 mol/l. Fig.4.The curve of lactate in the study group Other parameters which were analysed were Il-1 and IL-6; parameter which was analysed was IL-1, an APP, which had the following tendency: in Group I, IL-1 increased during the first 24 h, then rapidly getting back to normal, at the utmost in day 4 (fig. 5a), while in Groups II and III, the values were high even after this moment. As for IL-6, an APP, its values returned to normal within the first week in Group I (fig. 5b), while its curve was ascendant in Groups II and III, with a slow decrease in patients who survived with complications, a statistically significant correlation being identified (p=0.0008) between the value of IL-6 in day 6 and the onset of a lethal or non-lethal complication. The most relevant biochemical markers (ESR, CRP, Il-1, and Il-6) were also evaluated within each of the three groups in order to compare their behaviour under the same circumstances regarding the outcome of the patients. The results in the study group showed that: -In Group I, all the parameters have an initial raise, then descending continuously and somehow concordant until day 6, correlated with a favourable outcome (fig. 6a) -In Group II, with the patients who survived but with complications, all the curves have (even if in different moments) a bimodal aspect, suggesting that the complications can be correlated with a second hit; initially, the inflammatory markers decrease, due to the intervention of the compensatory mechanisms, then secondary increase again, due to the onset of the complications (fig. 6b) -In Group III, two different behaviours were described: in patients who died early, due to exhausting of the protective mechanisms, the inflammatory markers continuously increase (fig. 7a), while in late deaths, the Fig.5. Variations of IL-1 (a) and IL-6 (b) in the study group Fig.6. Biochemical parameters in Groups I (a) and II (b) REV.CHIM.(Bucharest) 69 No

5 Fig.7. Biochemical parameters in Group IIIearly deaths (a) and after complications (b) aspect is bimodal, but the second part of the curve is continuously ascendant, as the reactive systems are overridden (fig. 7 b) Due to their considerable morbidity and mortality, polytrauma patients need careful monitoring in order to adapt the treatment to the patients status. One of the most unfavourable situation is that of the polytrauma with femoral shaft fracture, as both the fracture and its treatment have a major systemic impact, being able to produce a so called second hit phenomenon, thus increase the risk of MSOF and even death. Therefore, a proper evaluation of the patients status in each moment of the treatment is mandatory in order to adapt the therapeutical attitude to any potential complication, and objective, measurable and reproducible elements should be used for that. These requests are met by some biochemical markers, suggestive for the inflammatory status of the patients, which were analysed in this study. Several aspects of this research need to be discussed: first of all, this study confirms the implication of SIRS and CARS into the pathogeny of polytrauma, and enhances the importance of indicating the proper treatment, as, most of the markers proved no statistical significant correlation between the initial value and systemic complications. The only exception is the lactate: as acidosis is one of the main pathogenic mechanisms in trauma, the magnitude of the initial trauma is reflected by the initial value of the lactate; thus explaining the statistically significant correlation between this and mortality; after the first hit, the initial trauma, all therapeutic means are directed to neutralising the pathogenic mechanisms, including the acidosis; the success of this action considerably influences the outcome of the patient, and failure to antagonise acidosis will lead to death; the statistically significant correlation between the value of lactate after 24 h and mortality reflects the efficacy of the initial treatment. Although this study achieve only a global analysis of the complications, without looking for specific correlations for each type of them ( septic, embolic, etc), it confirmed that the severity of the initial injury is crucial for the outcome of the patients- the complications were statistically significant more frequent in the Damage Control group, as these were unstable and borderline patients. The inflammatory markers were found to be suggestive for the late morbidity and mortality, thus demonstrating their value in polytrauma Conclusions This study demonstrated that certain biochemical markers can reflect the outcome of polytrauma patients: IL-1 in day 2, IL-6 in day 6, CRP and thrombocites in day 14 were statistically significant correlated with the onset of complications, which is concordant with their biochemical and functional characteristics. The most specific marker for early complications was proved to be IL-6, which went back to normal, if the outcome was favourable, while complications were associated with a plateau or an ascendant curve even later from day 6, classically considered the limit of the inflammatory phase. These conclusions have a considerable therapeutic value, as they fully describe the pathogeny of polytrauma using the objective, measurable biochemical markers for monitoring these patients and guide the treatment This study suggests that at least IL-1, IL-6, CRP and thrombocites should be routinely performed din polytrauma and should be introduced in the guidelines and recommendations as standard evaluation tools. References 1.*** 2.CARTIN-CEBA, R., HUBMAYR, R., QIN, R. Predictive value of plasma biomarkers for mortality and organ failure development in patients with acute respiratory distress syndrome. 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