Influence of antioxidant therapy on the clinical status of multiple trauma patients. A retrospective single center study

Abstract

Introduction

The biochemical processes of bioproduction of free radicals (FR) are significantly increasing in polytrauma patients. Decreased plasma concentrations of antioxidants, correlated with a disturbance of the redox balance are responsible for the installation of the phenomenon called oxidative stress (OS). OS action is associated with a series of secondary complications with direct implications in reducing the rate of survival, as well as in increasing morbidity The objectives of this study were to reveal possible relations between antioxidant therapy and a number of serum biochemical variables (ALT, AST, APPT, LDH, urea, leukocytes, platelets), the length of mechanical ventilation, the time spent in the ICU, and the mortality rate in major trauma patients.

Materials and methods

In this retrospective study from a single center, 64 medical files of polytrauma patients admitted to the ICU “Casa Austria” were analysed. The selection criteria were: the Injury Severity Score (ISS) > 16 and a systolic arterial pressure (SAP) < 89 mmHg. The selected patients (n = 34) were divided into two groups: Antiox group, 20 patients who benefited from antioxidant therapy and the Contr group, 14 patients who did not received antioxidant therapy and served as a control group. The antioxidant therapy consisted of the simultaneous administration of vitamin C (i.v.), vitamin B1 (i.v.) and N-acetylcysteine (i.v.). The clinical and the biological evaluation were performed repeatedly until discharge from the ICU or the death of the patient.

Results

No significant differences were highlighted concerning the demographic data, the magnitude or the trauma mechanism between the two groups. In comparison with patients from the Contr group, the patients submitted to antioxidant therapy showed lower values after the treatment for leukocytes (p = 0.0066), urea (p = 0.0076), LDH (p = 0.0238), AST (p = 0.0070) and ALT (p < 0.0001). No statistically significant differences were evidenced regarding the incidence of sepsis or the development of multiple organ dysfunction syndrome (MODS). The period of mechanical ventilation was longer in patients from the Contr group (p = 0.0498), with no differences concerning the ICU length of stay (p = 0.7313). The mortality rate was lower in the Contr group (p = 0.0475).

Conclusion

In multiple trauma patients a prolonged antioxidant therapy improved the posttraumatic laboratory tests.

Introduction

The production of reactive oxygen or nitrogen species occurs in the human body under normal circumstances. Patients with critical trauma have a drastically increased production of free radicals (FR) [1, 2]. In physiological conditions, the human body has an antioxidant autonomous system consisting of numerous enzymes and biomolecules able to interrupt the oxidative activity of FR: superoxide dismutase, catalase, glutathione, uric acid, methionine [3–8]. Hemorrhagic shock is associated with an increased level of FR, mainly due to ischemia-reperfusion syndrome [9–10].

Several studies have shown beneficial effects from the intravenous administration of antioxidants (AOX) (vitamin C, vitamines B, N-acetylcysteine) in patients with critically trauma and hemorrhagic shock [11–13].

Antioxidant therapy significantly reduces ischemia-reperfusion injuries and correlated with a significant decrease of mortality in critically ill patients [14–17].

The aim of our study was to identify possible relations between antioxidant therapy and the laboratory tests measured before and after therapy, in patients with critically trauma and hemorrhagic shock. Duration of mechanical ventilation, the ICU length of stay and the mortality rate were secondary endpoints.

Material and methods

Patients

This retrospective study was performed with the institutional Ethics Committee approval. Medical files of 64 patients admitted in the Anaesthesia and Intensive Care Unit (ICU) “Casa Austria” of the Polytraumatology Clinic from the Clinical Emergency Hospital “Pius Brînzeu” Timisoara, Romania during January 2014 – December 2014 were examined.

The inclusion criteria were: systolic blood pressure (SBP) < 89 mmHg, multiple trauma, and Injury Severity Score (ISS) > 16. The patients enrolled chronologically in the study, were divided into two groups: Antioxi group – 20 patients who benefited from antioxidant therapy and Contr group – 14 patients who did not receive antioxidant therapy and served as controls.

Not all patients admitted to the ICU during the previous year benefited from the antioxidant therapy which was administered discontinuously.

Prolonged antioxidant therapy

Antioxidant therapy consisted of the administration of Vitamin C, Vitamin B1 and N-acetylcysteine (NAC). All patients received Vitamin C (i.v): 1 g three times daily, for 5 days, vitamin B1 (i.v.): 100 mg daily for 3 days and N-Acetylcysteine (i.v.) 300 mg twice a day, for the whole period of the ICU stay. For patients who had an ICU stay longer than 9 days, starting with day 10, the treatment with Vitamin C and B1 was repeated until discharge or death of the patients.

Data Collection and Processing

From patients files we collected data concerning the trauma mechanism, associated injuries, admission module (direct admission/transfer from another hospital), the admission speed in ICU “Casa Austria” and the transfusional requirements. Clinical and demographic characteristics that were also recorded at admission in ICU included: gender, age, ISS, Apache II score, Glasgow Coma Scale (GCS) score < 7, invasive or noninvasive blood pressure, heart rate (HR), SpO₂, base excess (BE), lactate (Lac), temperature, haemoglobin (Hb), thrombocytes, leukocytes, international normalized ratio (INR), activated partial thromboplastin time (APTT), prothrombin time (PT), lactate dehydrogenase (LDH), urea, aspartate transaminase (AST), alanine transaminase (ALT) values. All patients received biological investigations conducted by the central laboratory of the hospital and ICU own laboratory during the stay in ICU. Subsequently, the humoral-biochemical markers were analyzed once every 24 hours until the moment of discharge from the ICU. Every patient’s data regarding days of mechanical ventilation, ICU length of stay and mortality were also recorded.

Statistical analysis

The statistical analysis of data was performed with Microsoft Office Excel for Mac 2011 v.14.4.7. (Microsoft Corporation, Bucharest, Romania) and Prism 6 for Mac OS X v.6.0. (GraphPad Software, Inc., San Diego, CA).

This analysis consisted of the calculation of frequencies and the percentages for qualitative variables, as well as the calculation of averages and standard deviations for the quantitative variables. The statistical comparison of the averages samples was made by the unpaired t-test and the statistical comparison of the percentages was made by the Chi square test. The statistical estimation of the results was performed using the criteria decision of the statistical test. Statistical significance was defined as p < 0.05.

Results

From the 64 medical files of patients admitted to ICU, in the study period, only 34 patients (53.12%) met the inclusion criteria and were allocated in the Antiox group (n = 20) and the Contr group (n = 14). Figure 1 illustrates the flow chart of the study.

Fig. 1.

The flowchart of the study (A – Antiox group, B – Contr group)

Data concerning the trauma mechanism, associated injuries, admission module (direct admission/transfer from another hospital), ICU length of stay and the transfusion requirements are presented in Table 1.

Table 1.

Data referring trauma mechanisms, associated injuries, time to admission and transfusion requirements

Characteristics		Antiox group (n = 20)	Contr group (n = 14)
Trauma mechanism, n (%)	Traffic accident	10 (50)	8 (57.1)
	Aggression	1 (5)	2 (14.2)
	Others	9 (45)	4 (28.5)
Associated injuries, n (%)	Head injury	6 (30)	11 (78.5)
	Thoracic injury	16 (80)	10 (71.4)
	Abdominal injury	4 (20)	5 (35.7)
	Extremities injury	12 (60)	6 (41.8)
Direct admission, n (%)		6 (30)	9 (64.2)
Time elapsed since the trauma to the admission in ICU “Casa Austria”, mean (SD), minutes		108.4 (210.7)	73.6 (99.3)
Blood transfusion at admission/emergency operating theater, n (%)	1 – 9 units	12 (60)	9 (64.2)
	10 + units	4 (20)	5 (35.7)

Fifty percent of patients from the Antiox group and 57.1% from the Contr group were admitted to the ICU following a road accident. Regarding the associated injuries, 30% from the Antiox group and 78.5% from the Contr group had suffered head injuries, 80% of patients from Antiox group and 71.4% of patients from the Contr group suffered thoracic injuries. Other common injuries in polytrauma patients were represented by extremities’ fractures and abdominal injuries. Of the 34 patients who entered into the study, 15 patients (44.1%) had primary admission on ICU, the others being transferred from other hospitals to the ICU “Casa Austria”, after more than 24 hours from the time of injury. The mean (SD) time between occurrence of trauma and the ICU admission in “Casa Austria” was 108.4 (210.7) minutes for patients from the Antiox group, and 73.6 (99.3) minutes for patients from the Contr group. The number of blood units transfused at admission and during emergency surgery was similar in the two groups.

At admission in ICU, the ISS score of the two groups was similar (p = 0.1157), and no differences were recorded concerning APACHE II score (p = 0.9690), SpO₂ % (p = 0.0685) or the number of patients with hypotension (p > 0.05). The contr group included a higher number of patients with altered neurologic status (GCS < 7) as compared with patients from the Antiox group which presented a lower mean temperature at admission (p < 0.0001) (Table 2).

Table 2.

Demographics and clinical data of the analyzed patients at admission in ICU

Variable	Antiox group (n = 20)	Contr group (n = 14)	p value
Gender, % male	75	85.71	0.7417
Age, mean (SD), years	52 (14.5)	53.8 (20.9)	0.7629
APACHE II, mean (SD)	10.7 (5.8)	10.8 (7.6)	0.9690
ISS, mean (SD)	26,1 (8,4)	31.1 (9.4)	0.1157
GCS < 7, n (%)	1 (5)	6 (42.8)	> 0.05
Arterial hypotension, n (%)	20 (100)	12 (84.7)	> 0.05
HR, mean (SD), bpm	100 (25)	106 (23)	0.4821
SpO2, mean (SD), %	92.5 (7.5)	88 (5.5)	0.0685
BE, mean (SD), mmol/L	− 5 (5.6)	− 9.9 (4.2)	0.0096*
Lac, mean (SD), mmol/L	3.9 (3.4)	5.1 (2.5)	0.2976
Temperature, mean (SD), °C	34.6 (0.6)	36 (1.2)	0.0001*
APTT, mean (SD), s	31.5 (9.8)	25.2 (1.8)	0.6750
PT, mean (SD), %	81.2 (11)	90 (1.5)	0.8894
INR, mean (SD)	1.8 (2.1)	1.7 (0.1)	0.8614
Hb, mean (SD), mg/dL	11.5 (3.1)	10.7 (1.5)	0.3789
Platelets (103/uI), mean (SD)	161 (89.5)	155.1 (71.5)	0.8409
Leukocytes (103/uI), mean (SD)	8.7 (2.5)	11.1 (2.8)	0.0161*
Urea (mg/dL), mean (SD)	59.5 (10.5)	64.1 (3.1)	0.1177
LDH (U/L), mean (SD)	610.3 (410)	725 (510)	0.4730
AST (U/L), mean (SD)	81.7 (1.9)	85 (17.7)	0.3890
ALT (U/L), mean (SD)	51.8 (15.9)	99 (21.9)	0.0001*

ISS = Injury Severity Score, GCS = Glasgow Coma Scale, SpO₂ = Peripheral Capillary Oxygen Saturation, BE = Base Excess, Lac = Lactic Acid, APTT = Activated Partial Thromboplastin Time, PT = Prothrombin Time, INR = International Normalized Ratio, Hb = haemoglobin, LDH = Lactate Dehydrogenase, AST = Aspartate Transaminase, ALT = Alanine Transaminase,

^*p < 0.05,

SD = standard deviation

Among the laboratory tests determined at admission, significantly more patients from the Contr group presented a reduced value of BE (p = 0.0096), an increased ALT value (p < 0.0001) and an increased number of leucocytes (p = 0.0161) (Table 2).

During the ICU stay, 17 patients developed sepsis: 8 in the Antiox group and 9 in the Contr group (p > 0.05), associated in 14 of them with multiple organ failure (MOF), with no differences between groups (p = 0.594).

In patients from the Antiox group the laboratory data were improved, while in patients from the Contr group remained elevated (Table 3).

Table 3.

Biochemical and humoral parameters at discharge from ICU

Variable	Antiox group (n = 20)	Contr group (n = 14)	p value
Leukocytes (103/uI), mean (SD)	9.6 (1.4)	12.2 (1.8)	0.0066*
Urea (mg/dL), mean (SD)	27.8 (10.5)	57.1 (20.8)	0.0076*
LDH (U/L), mean (SD)	575.3 (239.8)	1231 (469.3)	0.0238*
AST (U/L), mean (SD)	47.7 (19.2)	78 (15.7)	0.0070*
ALT (U/L), mean (SD)	45.6 (18.9)	89 (22.3)	< 0.0001*

LDH = lactate dehydrogenase, AST = aspartate transaminase, ALT = alanine transaminase,

^*p < 0.05,

SD = standard deviation

Antioxidant therapy determined significant differences between groups related to: ALT (p < 0.0001) (Fig. 2A), AST (p = 0.007) (Fig. 2B), APTT (p > 0.05) (Fig. 2C), leukocytes (p = 0.0066) (Fig. 2D), platelets (p > 0.05) (Fig. 2E), LDH (p = 0.0238) (Fig. 2F), urea (p = 0.0076) (Fig. 2G).

Fig. 2.

Graphical representation of biochemical humoral mean values at discharge from ICU; (A) ALT (p < 0.0001), (B) AST (p = 0.007), (C) APTT (p > 0.05), (D) leukocytes (p = 0.0066), (E) platelets (p > 0.05), (F) LDH (p = 0.0238), (G) urea (p = 0.0076). ALT = alanine transaminase, AST = aspartate transaminase, APTT = activated partial thromboplastin time, LDH = lactate dehydrogenase, *p < 0.05

A number of 26 patients required mechanical ventilation more than 96 h, significantly less in the Contr group as compared with the Antiox group (p = 0.049).

The mean (SD) length of stay in ICU was 11.7 (11.9) days for the Antiox group and 13 (10) days for the Contr group (p = 0.7513).

Fifteen patients died, 6 in the Antiox group and 9 in the Contr group. Hence, the registered mortality in the Antiox group (n = 20) was 30 % and in the Contr group (n = 14) was 64.2% (p = 0.0475).

Discussion

It is well known that oxidative stress represents an important threat in patients with major trauma [18].

Along with recent changes in pharmaconutrition, a new strategy that enhances cellular defense, decreases oxidative stress and diminishes systemic inflammatory response, to improve outcome in major trauma is being considered.

Naturally, the human body has an antioxidant autonomous system consisting of a number of enzymes or biomolecules able to interrupt oxidative activity of FR: superoxide dismutase, catalase, glutathione, uric acid, methionine [3, 6]. In the critically ill due to major physiological imbalances and hypermetabolism, patients no longer have an antioxidant-oxidant balance. If sepsis is a concurrent event antioxidant capacity decreases significantly due to acute inflammatory response, hypermetabolism or inadequate nutrition as long as OS level is increased due to the overproduction of FR through nicotinamide adenine dinucleotide phsphate oxidase, xanthine oxidase, lipoxygenase, oxidation of catecholamines or cyclooxygenase [7, 8]. It seems obvious that an inadequate balance between production and demands on antioxidants will lead to a worsening situation.

Even if numerous animal experimental studies have highlighted the protective effects of antioxidant substances on FR, there are few clinical works on this topic. Abiles et al., in their study on oxidative stress on the critical patient, showed significant correlations between oxidative stress and a number of critical common diseases [17].

In a recent meta-analysis authors searched for the potential benefits of antioxidants in the critically ill but the majority had endpoints such as mortality, infections complications, and length of stay and showed a great variability in the administration of combination micronutrients/antioxidants as well as different dosages [19].

A primary goal of our study was to establish possible correlations between antioxidant therapy and laboratory tests courses in traumatized patients, meanwhile searching for a patient’s outcome.

Even if they are limited by the study’s retrospective nature, the results of our study showed a positive/favorable course of the humoral biochemical parameters, as a secondary effect of the antioxidant therapy, in group Antiox (Table 3).

Leukocytes and platelets in normal physiological conditions fulfill a number of functions, which include the ability to modulate the pro-inflammatory factors, thrombosis or systemic biological control signals [20]. A directly proportional link between serum levels of leukocytes, platelets and that of a number of specific side effects of oxidative stress: mitochondrial dysfunction and loss of ATP synthase activity have been reported and are considered essential biomarkers of lipid peroxidation [21]. Our study showed a statistically significant difference between the groups regarding leukocytes count (p = 0.0066) and no differences in platelet count (Figure 2).

It has been documented that AST and ALT are considered significant biomarkers for oxidative injuring brought by FR [16]. Our results highlight a statistically significant difference regarding the values of AST and ALT levels in patients from the Antiox Group (AST: p = 0.0070, ALT: p < 0.0001) (Figure 2) at the end of ICU stay.

Oxidative stress leads to membranes destruction and consequently to a significant increase of LDH levels. Experimental studies have proven that Vitamin C administration is able to inhibit this cell membrane denaturation [21, 22]. The value of ascorbic acid and N-acetyl-cysteine (NAC) could be still controversial as in a recent study Childs et al. showed that vitamin C and NAC could act as pro-oxidants in humans during inflammatory conditions. By inducing an acute-phase inflammatory response by an eccentric arm muscle injury, authors noted that administration of vitamin C and NAC transiently increased tissue damage (by elevation of LDH and creatinkinase) and oxidative stress [23]. In our study all humoral parameters evidenced a significant decrease, including LDH, toward normalization in the group which was under antioxidant therapy (p = 0.023).

Recently, Peluso et al. demonstrated that increased levels of urea accelerate the production of FR [24]. We found a significant difference between groups regarding serum levels of urea (p = 0.0076) (Figure 2), and we suppose that antioxidants might have played a role in reducing FR release.

The imbalance between endogenous antioxidants and the biosynthesis of FR seems responsible for the systemic inflammatory response and finally leads to severe organs dysfunction [25]. We did not register differences between groups regarding MODS but antioxidant therapy beneficiaries evidenced a significant shorter period of ventilator support (p = 0.049). The ICU length of stay was 11.7 ± 11.9 days, in Antiox group, and 13.2 ± 13.9 days in the Contr group (Figure 3). However, we did not note any significant differences regarding the influence of antioxidant treatment upon ICU stay (p = 0.7513). A reduced mortality was found in the Antiox group (p = 0.047), which could be attributed to the antioxidant therapy, although a difference in the severity of the injury at admission between the groups cannot be ruled out. In spite of the lack of differences concerning the ISS score, the APACHE II score, SpO₂ %, and the number of patients with hypotension, a higher number of patients in the control group were admitted with an altered neurological status, reduced values of BE and increased ALT values. However, a recent meta-analysis of 18 randomized controlled trials examined the impact of AOX on endpoints such as mortality, infections complications, and LOS. They concluded that in critically ill patients, micronutrient therapy (including antioxidants) was beneficial, with a suggested decrease in mortality [19, 26, 27].

There are several limitations of this study that hinder the capacity of drawing firm conclusions. There were differences regarding conditions severity between groups, and it was difficult to appreciate if the patient’s outcome in the Antiox group would have been different in the absence of antioxidant therapy. Our results are limited because of the retrospective nature of this study and the reduced number of patients.

Conclusions

This study showed a significant improvement of the humoral biochemical parameters in patients with major trauma who received antioxidant therapy. Further prospective studies should be undertaken to establish the benefits of counteracting oxidative stress in severe trauma patients.