a b s t r a c t

Background: Carbon monoxide poisoning is associated with cardiac injuries or manifestations, frequently at- tributing to direct hypoxic damage at cellular level. For this, the aims were to evaluate the role of serum Pentraxin 3 (PTX 3), ischemia-modified albumin , and Myeloperoxidase as an early biomarker for Cardiac damage when compared to cardiac troponin I (cTnI) and creatine kinase-MB fraction (CK-MB) in adult patients with acute CO poisoning.

Methods: Forty patients with acute CO poisoning admitted to the emergency department. The patients were divided into 2 main groups as follows: cardiac injury (group I, n = 19) and nonsuspected cardiac injury (group II, n = 21). Pentraxin 3, IMA, MPO, cTnI, CK-MB, and the other assays in the circulation were measured on admission.

Results: Upon measuring the serum PTX 3, IMA, MPO, cTnI, and CK-MB levels as well as large electrocardiography and echocardiography abnormalities of patients with cardiac injury on admission, no statistical difference for PTX 3, IMA, and MPO was found between the groups (P N .05). However, cTnI, CK-MB, and leukocyte count (white blood cell) were higher determined in patients of group I compared to group II (P b .05). Receiver oper- ating characteristic curve was also performed to evaluate the diagnostic performance of these tests in patients with cardiac injury.

Conclusions: Our results suggest that PTX, IMA, and MPO assays are not superior to cTnI and CK-MB in predicting a cardiac damage in patients with acute CO intoxication.

(C) 2016

Introduction

Carbon monoxide (CO) is a toxic gas known as a silent killer among individuals in the community and results from not exactly combustion of compounds containing carbon. A person may breathe CO gas acciden- tally or with the purpose of suicide, resulting in CO intoxication. Carbon monoxide poisoning is a serious cause of morbidity and mortality worldwide [1-3]. Clinical findings in Poisoned patients are associated with the duration of CO exposure and inhaled CO concentration. Thus, findings of the poisoning include a spectrum from mild to moderate complaints such as headache, dizziness, and weakness to serious clinical manifestations which may result in convulsions, cardiovascular col- lapse, and even death [4,5]. Previous studies have implicated that CO in- toxication usually lead to cardiotoxicity in innocent subjects after moderate to severe CO poisoning [3,6,7]. Latest reports suggest that

* Corresponding author at: Department of Emergency Medicine, Faculty of Medicine, Ondokuz Mayis University, Kurupelit, 55139 Samsun, Turkey. Tel.: +90 362 3121919×2096; fax: +90 362 4576041.

E-mail address: [email protected] (A. Baydin).

hypoxia is the most probably underlying cause of cardiac injury or cardiotoxicity after CO poisoning [1,5,8]. The degree of cardiotoxicity is highly variable in patients with CO intoxication [9-11]. To make a di- agnosis of cardiac injury, echocardiography, biochemical markers, and the resting electrocardiographic are key components for the proper assessment of a patient with a suspected CO intoxication. The markers of cardiac injury, predominately cardiac troponin I (cTnI), cre- atine kinase-MB (CK-MB), Ischemia-modified albumin , and heart-type fatty acid binding protein as well as B-type natri- uretic peptide are also the major tests in the diagnosis of patients with CO intoxication [3,5,7,12-14]. Carbon monoxide in blood circulation also leads to platelet-to-neutrophil aggregation and release of myeloperoxidase (MPO), proteases, and Reactive oxygen species, lead- ing to oxidative stress, lipid peroxidation, and apoptosis [15,16].

Previous scientific reports have presented that pentraxin 3 levels in the circulation are raised clearly in patients with acute myocardial infarction and unstable angina pectoris [17]. Pentraxin 3 is also expressed in response to many proinflammatory signals including ischemic and hypoxic clinic conditions [17,18]. As well as elec- trocardiography and echocardiography, both clinical features and

http://dx.doi.org/10.1016/j.ajem.2016.05.043

0735-6757/(C) 2016

1928 A. Baydin et al. / American Journal of Emergency Medicine 34 (2016) 1927-1930

laboratory tests are considerable important for accurate diagnosis in poisonings in relation to cardiac injury. Therefore, our aim is to examine whether PTX 3, IMA, and MPO are able to be an early biomarkers for myocardial damage when compared to cTnI, CK-MB, and cardiac mani- festations in patients with acute CO poisoning.

Materials and methods

From September 2013 to March 2015, we prospectively enrolled consecutive patients admitted to the emergency department (ED) that visits annually 57 000 adult patients at university hospital. The study had an approval procedure from the local research ethics committee (ethics approval no. PYO.TIP.1901.13.036). The minimum number of pa- tients needed for each group was determined by power analysis. For IMA, while d = 0.12, ? = 0.05, ? = 0.05, and power of 95%, the mini- mum number is n = 6 [12]. A total of 40 adult patients (N 18 years) with CO poisoning were involved in this study. Six patients were ex- cluded from the present prospective study due to lack of medical data. Carbon monoxide intoxication was diagnosed according to patient his- tory and Carboxyhemoglobin levels in the bloodstream. Detailed histo- ries were taken from patients or patients’ relatives; their physical examinations were performed.

The patients admitted to the ED within 6 hours after intoxication were accepted as acute CO poisoning. Patient demographics, presenting vital signs (blood pressure, respiratory rate, heart rate, and temperature), presenting symptoms, exposure time of CO gas, cause of CO gas, and Glasgow Coma Scale score were recorded upon presentation in the ED. Complete blood count, cardiac biomarkers (cTnI, CK-MB) results, ECG, arterial blood gas measurements, the blood Carboxyhemoglobin levels, and chest radiography were obtained in all the cases (Table).

The patients were divided into 2 main groups as follows: group 1, cardiac injury; group 2, nonsuspected cardiac injury. A diagnostic crite- rion of cardiac injury was defined as loss of consciousness, an elevated cardiac biomarkers (CK-MB, N 3.23 ng/mL; cTnI, N 0.1 ng/mL) [3,6], is- chemic changes on ECG, and wall motion abnormalities on echocardiog- raphy. Ischemic changes were classified as new ST-segment elevation (>= 1 mm), depression (>= 0.5 mm), or T-wave inversion (>= 2 mm) in 2 consecutive leads [19]. Electrocardiograms were reviewed indepen- dently from clinical data by a specialist doctor of emergency medicine and were classified by rhythm and ST-T wave changes. Echocardio- grams classified by ejection fraction and wall motion abnormalities were performed by a specialist doctor of cardiology within 2 to 4 hours admitted to ED. Patients were evaluated by a System 7 Vingmed echocardiography device (General Electric Medical System, Horten, Norway) using a 2.5-MHz probe on admission.

In the present study, the exclusion criteria included the following:

(1) patients with CO poisoning younger than 18 years; (2) clinical and toxicologic data were insufficient to permit the diagnosis of carbon monoxide poisoning; (3) the presence of coronary artery diseases histo- ry before the carbon monoxide poisoning; (4) chronic obstructive pul- monary diseases; (5) smoking history; and (6) patients admitted to the ED after receiving medical treatment in another health institution.

After initial evaluation, fluid and Oxygen treatment were adminis- tered to all patients in the ED. Those in Serious condition were intubated and were connected to the mechanical ventilation and then hospitalized in intensive care unit.

Blood samples and measurements

Blood samples for the detection of PTX 3, IMA, and MPO were taken from patients who have the first clinical symptoms of CO intoxica- tion upon arrival to the ED. Serum was separated and stored at -80?C until analysis. Pentraxin 3, IMA, and MPO levels were measured in serum samples by enzyme-linked immunosorbent assay method using a kit from Sun. Red Biotechnology Company (catalog no.

Table

Baseline demographic and clinical characteristics of study population

Variables Cardiac injury Nonsuspected cardiac P

injury

Group I (n = 19) Group II (n = 21)

Age (y)	52.4 +- 18.3	42.3 +- 18.1
Sex (F/M)	12/7	14/7
Vital signs on admission
SBP (mm Hg)	121.8 +- 19.5	117.1 +- 24.6
DBP (mm Hg)	72.6 +- 10.7	71.6 +- 10.9
Heart rate (beats/min)	99.8 +- 23.4	82.2 +- 7.8
Respiratory rate (breaths/min)	23.2 +- 6.1	21.5 +- 3.6
Temperature (?C)	36.3 +- 0.5	36.3 +- 0.4
initial symptoms
Headache	1 (5.3%)	8 (38.1%)
Dizziness	1 (5.3%)	1 ( 4.8%)
Weakness and fatigue	1 (5.3%)	8 (38.1%)
Vomiting	-	1 ( 4.8%)
Loss of consciousness or syncope	16 (84.2%)	3 (14.3%)
ECG findings on admission
Normal sinus rhythm	6 (31.6%)	14 (66.7%)
Sinus tachycardia	7 (36.8%)	6 (28.6%)
Atrial fibrillation	2 (10.5%)	-
ST-T wave variation	3 (15.8%)	1 (4.7%)
Asystole	1 (5.3%)	-
Cause of exposure to CO poisoning
Stove (coal or wood)	15 (78.9%)	17 (81.0%)
Barbecue	1 (5.3%)	-
Hot water boiler	3 (15.8%)	3 (14.3%)
Gas boiler	-	1 (4.8%)
Exposure time of CO gas (h) 1.8 +- 0.9		1.5 +- 1.1
Arterial blood gas analysis
pH 7.3 +- 0.1		7.4 +- 0.1
PO2 (mm Hg) 79.6 +- 54.3		57.2 +- 39.5
PCO2 (mm Hg) 33.8 +- 9.1		38.5 +- 5.1
SaO2 (%) 80.5 +- 23.2		75.7 +- 23.8
Glasgow Coma Score at admission
GCS 14-15	14 (73.7%)	21 (100%)
GCS 9-13	4 (21.1%)	-
GCSb 9	1 (5.3%)	-
Echocardiography findings on admission
Normal echocardiography findings	3 (15.8%)	21 (100%)
Wall motion abnormalities	7 (36.8%)	-
Ejection fraction (b45%)	9 (47.4%)	-

Final outcome

Discharged 17 (89.5%) 21 (100%)

Exitus 2 (10.5%) -

Laboratory findings

COHb (%)	23.8 +- 13.6	19.5 +- 12.6	N.05
cTnI (ng/mL)	0.94 +- 2.03	0.006 +- 0.01	b.05
CK-MB (U/L)	11.4 +- 17.5	1.4 +- 1.3	b.05
PTX 3 (pg/mL)	1817.4 +- 1247.7	1800.1 +- 1927.9	N.05
IMA (ng/mL)	165.7 +- 102.9	147.6 +- 66.2	N.05
MPO (pg/mL)	32 324.0 +- 12 304.6	30 952.1 +- 12 892.6	N.05
WBCs (/mm3)	15 188.9 +- 6185.2	9042.4 +- 2298.4	b.05
AST (U/L)	38.9 +- 38.9	23.9 +- 17.5	N.05
ALT (U/L)	26.9 +- 20.9	22.2 +- 20.7	b.05

Abbreviations: M, male; F, female; SBP, systolic blood pressure; DBP, diastolic blood pres- sure; AST, aspartate aminotransferase; ALT, alanine aminotransferase.

DZE201121173, lot no. 201505), Boster Biological Technology Co, Ltd (catalog no. EKO850, lot no. 50010282227), and Boster Biological Technology Co, Ltd (catalog no. EK0861, lot no. 5111025320), respec- tively. Creatine kinase-MB and cTnI levels were measured in serum by Simens ADVIA Centaur Cp analyzer, and leukocyte count was mea- sured in the whole blood by Simens Advia 2120i analyzer and the other analyses were determined by Roche Cobas Integra 800 analyzer in emergency laboratory.

Statistical analysis

Statistical analyses were performed with use of a SPSS 18 for Win- dows (SPSS, Chicago, IL). The data were presented as mean +- SD or as frequency (%). The Shapiro-Wilk test was used to analyze normal

Baydin et al. / American Journal of Emergency Medicine 34 (2016) 1927-1930 1929

distribution assumption of the quantitative outcomes. To compare 2 in- dependent groups, we used the Student t and Welch tests for normal data and Mann-Whitney U test for nonnormal data. ?² Tests were used for comparisons of percentages. These were Pearson ?², continuity correction ?², and Fisher exact tests. Receiver operating characteristic curve was used to illustrate and evaluate the diagnostic performance of data. P b .05 was considered as statistically significant.

Results

The baseline demographic and clinical characteristics of the patients are presented in the Table. Upon measuring the serum PTX 3, IMA, MPO, cTnI, and CK-MB levels as well as large electrocardiography and echo- cardiography abnormalities of patients with cardiac injury on admis- sion, no statistical difference for PTX 3, IMA, and MPO was found between groups I and II (P N .05). However, cTnI, CK-MB, and white blood cells (WBCs) were determined to be higher statistically in pa- tients of group I compared to group II (P b .05) as shown in the Table. diagnostic values of cTnI, CK-MB, PTX 3, IMA, and MPO tests to make an assumption in patients of group I with acute CO poisoning were shown in the Figure and its legend. When receiver operating character- istic analysis was performed for 5 biomarkers, area under curve values for cTnI and CK-MB were found to be P b .001 which indicates that these 2 markers may be used as tools in diagnosis of cardiac damage. Cutoff values for cTnI and CK-MB were found to be 0.025 and 2.37, re- spectively. Four-eyed table statistics revealed that, although sensitivity was 94.7%, specificity was 90.5%, positive predictive value was 90.0%, and negative predictive value was 95.0% for cTnI; for CK-MB, sensitivity was 84.2%, specificity was 85.7%, positive predictive value was 84.2%, and negative predictive value was 85.7%. Area under curve values for PTX 3, IMA, and MPO were found to be P N .05. Four-eyed table statistics were not calculated because these 3 markers were shown not to have a diagnostic value in indicating cardiac injury.

Discussion

Carbon monoxide poisoning affects individuals in a broad spectrum of age [19]. Although Elderly people are known to be vulnerable to toxic effects of CO poisoning and repeated poisonings [20], many studies re- vealed that younger adults are more likely to be affected from CO poi- soning [4,7,13]. Accordingly, a mean age of the patients exposed to CO poisoning in our study was 47.1 years.

cardiovascular involvement in CO poisoning can be clinically occult and often remains undiagnosed because of the lack of overt symptoms or specific ECG changes [25]. The most common ECG abnormality among patients with CO poisoning was determined to be arrhythmia

Figure. Diagnostic values of cTnI, CK-MB, PTX 3, IMA, and MPO tests to make an assump- tion in patients with cardiac injury in acute CO poisoning.

in our study. In a study on effects of CO poisoning on cardiovascular sys- tem, sinus tachycardia was reported to be the most common ECG abnor- mality [22]. In another studies, sinus tachycardia was determined in 41% to 49% of the patients [3,14].

Pathphysiologic mechanism CO poisoning consists of a tissue hypox- ia caused by CO-mediated molecular pathologic events. Carbon monox- ide binds to hemoglobin molecules with high affinity, displacing O₂ and generating carboxyhemoglobin that is nearly ineffective to deliver O₂ to the organ tissues. The organs with the highest demand for O₂, in partic- ular, the brain and heart, are much vulnerable to tissue injury. In addi- tion to hypoxic tissue damage, CO generates myocardial injuries with cardiospecific mechanisms, the clinic spectrum related to heart encom- passes cardiomyopathy, angina attack, myocardial infarction, arrhyth- mias, and heart failure up to Myocardial stunning, cardiogenic shock, and sudden death [2,3,12]. Carbon monoxide poisoning is considered to have occurred at COHb values of more than 10%, but Severe poisoning is associated with levels more than 20% to 25%, related to symptoms of severe cerebral or cardiac ischemia. In the present study, COHb levels were measured as 23.8% +- 13.6% in patients with acute CO intoxication. Thus, our patient’s COHb levels appear to be corresponding with moder- ate to severe poisoning along with echocardiography findings on admis- sion as indicated in the Table.

Carbon monoxide exposure also leads to inflammation through dif- ferent pathways that are independent of the pathways hypoxia, resulting in neurologic and cardiac injuries [16]. By the way, PTX 3, IMA, and MPO levels are to increase in the bloodstream in obvious in- flammatory, hypoxia, and oxidative stress conditions [12,15,17,18,23]. In a study on 50 consecutive patients, plasma MPO concentration was found 5-fold elevated in patients with acute CO poisoned, indicating that CO exposure triggers platelet-neutrophil aggregation and neutro- phil activation-degranulalation [15]. Myeloperoxidase liberated by neu- trophils mediates oxidative stress. In our study on 19 patients, no significant difference was observed for MPO levels between the groups; however, its levels were measured as mildly high in patients with suspected clinical myocardial injury in acute CO poisoning. A couple of scientific reports focus interest in a new biomarker IMA for an earlier di- agnosis of CO intoxication and detection of myocardial injury after acute ischemia. In 2 studies by Turedi et al [12] and Durukan et al [24], IMA levels in consecutive patients on admission in the ED were established as higher in CO poisoning compared to control. In contrast to 2 reports, we could not observe significant difference for serum IMA values be- tween groups I and II.

Pentraxin 3 is expressed in a high rate in Acute stage of acute coro- nary conditions that involve Endothelial cells, macrophages, neutro- phils, dendritic cells, smooth muscle cells, and cardiomyocytes [17,18]. Regarding PTX 3, there are no data in the literature in connection to a biomarker for cardiac damage in acute CO poisoning. In the current study, PTX 3 concentration is measured as slightly high in patients with suspected clinical myocardial injury compared to group I in acute CO intoxication, but no significant difference was observed for its values between the groups. Actually, cTnI and CK-MB supported by clinical his- tory, physical, and ECG findings are the criterion standard biomarkers for identifying myocardial damage to clinicians. Thus, cTnI and CK-MB are highly sensitive and specific indicators of myocardial dysfunction in association with acute CO poisoning. Pentraxin 3, IMA, and MPO have a poor diagnostic value in comparison with cTnI, CK-MB, and WBC tests to enable a more rapid diagnosis of cardiac dysfunction as shown in the Table, the Figure, and its legend.

Limitations of the study

Our study also has some limitations. Small subject size may affect the results of our study. In addition, we could not perform an appropri- ate follow-up for the patients in the ED. Another limitation is that Hyperbaric oxygen therapy could not be performed due to lack of an advanced center.

1930 A. Baydin et al. / American Journal of Emergency Medicine 34 (2016) 1927-1930

Conclusion

Although cardiotoxicity is thought to be the main cause of mortality in acute CO poisoning, the early diagnosis of cardiac damage is frequent- ly difficult [21]. Determination of cardiac injury in the early stage is es- sential to decrease morbidity and mortality. However, in our study, PTX 3, IMA, and MPO assays were found to be insufficient in indicating a car- diac damage, in comparison with cTnI and CK-MB in patients with acute CO poisoning. The main predictors of cardiac injury in acute CO poi- soned patients are still ischemic findings in ECG and elevated current serum cardiac markers.

Conflict of interest

The authors have no conflicts of interest existing with any compa- nies/organizations whose products or services may be discussed in this article. This manuscript has not been previously published and is not under consideration for publication elsewhere.

Acknowledgments

The authors would like to thank Dr Leman Tomak for statistical advice. This work was in part supported by the “Scientific Research Project” for young scientists of the Faculty of Medicine at Ondokuz Mayis University.

References

1. Lee FY, Chen WK, Lin CL, Kao CH. Carbon monoxide poisoning and subsequent car- diovascular disease risk: a nationwide population-based cohort study. Medicine (Baltimore) 2015;94:e624.
2. Lippi G, Rastelli G, Meschi T, et al. Pathophysiology, clinics, diagnosis and treatment of heart involvement in carbon monoxide poisoning. Clin Biochem 2012;45: 1278-85.
3. Satran D, Henry CR, Adkinson C, et al. Cardiovascular manifestations of moderate to severe carbon monoxide poisoning. J Am Coll Cardiol 2005;45:1513-6.
4. Kao HK, Lien TC, Kou YR, Wang JH. Assessment of myocardial injury in the emergen- cy department independently predicts the short-term poor outcome in patients with severe carbon monoxide poisoning receiving mechanical ventilation and hy- perbaric oxygen therapy. Pulm Pharmacol Ther 2009;22:473-7.
5. Garg J, Krishnamoorthy P, Palaniswamy C, et al. CardioVascular abnormalities in car- bon monoxide poisoning. Am J Ther 2014;1-10 [Epub ahead of print].
6. Henry CR, Satran D, Lindgren B, et al. Myocardial injury and long-term mortality fol- lowing moderate to severe carbon monoxide poisoning. JAMA 2006;295:398-402.
7. Kalay N, Ozdogru I, Cetinkaya Y, et al. Cardiovascular effects of carbon monoxide poi- soning. Am J Cardiol 2007;99:322-4.
8. Gandini C, Castoldi AF, Candura SM, et al. Carbon monoxide cardiotoxicity. J Toxicol Clin Toxicol 2001;39:35-44.
9. Chamberland DL, Wilson BD, Weaver LK. Transient cardiac dysfunction in acute car- bon monoxide poisoning. Am J Med 2004;117:623-5.
10. Ryoo SM, Sohn CH, Kim HJ, et al. Intracardiac thrombus formation induced by carbon monoxide poisoning. Hum Exp Toxicol 2013;32:1193-6.
11. Grieb G, Simons D, Piatkowski A, et al. Carbon monoxide intoxication versus myo- cardial infarction: an easy diagnosis? Burns 2011;37:e29-31.
12. Turedi S, Cinar O, Kaldirim U, et al. Ischemia-modified Albumin levels in carbon mon- oxide poisoning. Am J Emerg Med 2011;29:675-81.
13. Erenler AK, Yardan T, Baydin A, et al. Heart-type fatty acid-binding protein as a po- tential biomarker of acute carbon monoxide poisoning. Am J Emerg Med 2013;31: 1165-9.
14. Koylu R, Cander B, Dundar ZD, et al. The importance of H-FABP in determining the severity of carbon monoxide poisoning. J Clin Med Res 2011;3:296-302.
15. Thom SR, Bhopale VM, Han ST, et al. Intravascular neutrophil activation due to car- bon monoxide poisoning. Am J Respir Crit Care Med 2006;174:1239-48.
16. Weaver LK. Clinical practice. Carbon monoxide poisoning. N Engl J Med 2009;360: 1217-25.
17. Inoue K, Kodama T, Daida H. Pentraxin 3: a novel biomarker for inflammatory car- diovascular disease. Int J Vasc Med 2012;1-6. http://dx.doi.org/10.1155/2012/ 657025.
18. Kume N, Mitsuoka H, Hayashida K, Tanaka M. Pentraxin 3 as a biomarker for acute coronary syndrome: comparison with biomarkers for cardiac damage. J Cardiol 2011;58:38-45.
19. Aslan S, Uzkeser M, Seven B, et al. The evaluation of myocardial damage in 83 young adults with carbon monoxide poisoning in the East Anatolia region in Turkey. Hum Exp Toxicol 2006;25:439-46.
20. Acikalin A, Satar S, Sebe A, et al. H-FABP in cases of carbon monoxide intoxication ad- mitted to the emergency room. Hum Exp Toxicol 2011;30:443-7.
21. Chiew AL, Buckley NA. Carbon monoxide poisoning in the 21st century. Crit Care 2014;18:221.
22. Colomp-Lippa D. Acute carbon monoxide exposure: diagnosis, evaluation, treat- ment. JAAPA 2005;18:41-6.
23. Baydin A, Amanvermez R, Tuncel OK, et al. Ischemia-modified albumin is not beter than creatine kinase-MB and cardiac troponin I in predicting a cardiac injury in nontraumatic subaracnoid hemorrhage. Am J Emerg Med 2015;33:488-92.
24. Durukan P, Koyuncu M, Salt O, et al. Comparison of ischemia modified albumin levels with total oxidant, total antioxidant status, oxidative stress index in carbon monoxide poisoning. Acta Med Mediterr 2014;30:601-5.
25. Davutoglu V, Gunay N, Kocoglu H, et al. Serum levels of NT-ProBNP as an early car- diac marker of carbon monoxide poisoning. Inhal Toxicol 2006;18:155-8.