[The impact of L-carnitine administration on the serum level of myocardium injury markers in patients with acute carbon monoxide poisoning].

OBJECTIVE: To examine the serum level of myocardial injury markers in patients with carbon monoxide (CO) poisoning, the correlation between these markers and the severity of the disease, and the therapeutic effects of L-carnitine administration.

METHODS: 69 patients, chosen from 309 cases of acute carbon monoxide poisoning (ACOP) for abnormally high level of serum myocardial injury markers (myoglobin, Mb; MB isoenzyme of creatine kinase, CK-MB; cardiac troponin-I, cTnI) at the time of admission, were randomly divided into control group (n = 34) and observation group (n = 35). The patients in control group were given Xingnaojing (20 ml/d i.v. drip), and the observation group Xingnaojing (20 ml/d)+L-carnitine (2 g/d i.v. drip), in addition to the conventional oxygen supply and symptom-focused therapy. The plasma concentration of carboxyhemoglobin (HbCO, as index for CO poisoning severity), Mb, CK-MB, and cTnI in these patients were further examined 24 hours, 72 hours and 1 week after the treatment, for difference between the two groups, and the correlation between the serum level of HbCO and the myocardial injury markers.

RESULTS: At the time of admission, the incidence of abnormal findings in myocardial injury markers were 2.5% (5/204), 46.8% (36/77) and 100.0% (28/28) in patients with mild (HbCO: 10% ~ 19%), moderate (20% ~ 39%) and severe (≥40%) CO poisoning, respectively. The incidence of abnormal findings in injury markers was significantly correlated to the HbCO concentration (x(2)=170.3549, P < 0.0001). Before the treatment, no significant difference was found in any of the indexes [HbCO: (31.1 ± 17.6)%, (32.3 ± 16.9)%, Mb (μg/L): 154.2 ± 51.8, 165.4 ± 48.6, CK-MB (μg/L): 8.7 ± 3.3, 9.6 ± 3.8), and cTnI (μg/L): 2.7 ± 1.2, 2.8 ± 1.5, all P > 0.05] between the control and observation group. However, it was found in: Mb (24 hours: 74.0 ± 36.5 vs. 97.1 ± 35.8, 72 hours: 40.1 ± 6.8 vs. 69.0 ± 11.2), cTnI (24 hours: 1.9 ± 0.5 vs. 2.3 ± 0.7, 72 hours: 1.2 ± 0.3 vs. 1.8 ± 0.4) both 24 hours and 72 hours after the treatment, and CK-MB, 24 hours after treatment (10.6 ± 4.1 vs. 13.0 ± 3.9) with the values in observation group significantly lower (P < 0.05 or P < 0.01); 1 week after the treatment, the concentration of all the injury markers returned to the normal levels with no significant difference between the two groups. Meanwhile, no significant difference was found between the two groups in HbCO concentration throughout the due-course of the therapy.

CONCLUSIONS: The incidence of abnormal findings in serum myocardial injury markers was positively correlated with HbCO concentration after CO poisoning. L-carnitine may protect the myocardium and striated muscles against injury in patients with CO poisoning.