The efficacy of high performance liquid chromatography (HPLC) for the diagnosis of intoxication patients in the emergency room and ICU

Background

After the chemical weapon terrorism with SARIN (methyphosphonofluoridic acid 1-methyl-ethyl ester), a nerve agent used in Tokyo, Japan in 1995, the Ministry of Health and Welfare set up the chemical material's analyzers for countermeasure immediately at 73 emergency centers in Japan. On the other hand, there are no rare intoxication patients who are transferred to the emergency center and admitted in the ICU because of unconsciousness and critical cases. It is important to judge chemical materials for intoxication cases immediately and also to discriminate what cause to unconsciousness by intoxication or other diseases. The purpose of this study is to assess the efficacy of HPLC in the emergency room and ICU for the unconscious and critical patients caused by intoxication compared with Triage^® (Biosite Diagnostics, San Diego, CA, USA), which is the usual method.

Materials and Methods

The clinical records of 120 intoxication patients who underwent treatment in our emergency room and ICU between 1999 and 2002 were reviewed retrospectively. These patients included 40 men and 80 women ranging in age from 17 to 84 years (mean 33 ± 2.1 years).

To evaluate the usefulness and efficacy of HPLC for the critical cases, we surveyed the detective ability, the duration of examination, the expense per sample and the technical skill of HPLC compared with Triage^®.

Results

The drugs and poisons that patients took are presented in Table 1. Table 2 shows characteristics of HPLC and Triage^®. 44.8% of drugs and poisons were detected only by Triage^® and they are some benzosiazepines, hemp and stimulants. Also, HPLC was not useful for them. 25.4% of materials were positive by HPLC but negative by Triage^®. These chemicals were carbamazepine, levomepromazine, bromovalerylurea and agricultural chemicals. 9.7% were detected with both of HPLC and Triage^®, but 20.1% were not detected with either HPLC or Triage^®. These chemicals were nicotine, magic mushrooms, bleach, lithium carbonate, and insecticide (Table 3).

Table 1

Table 2

Table 3

Discussion

HPLC is superior to specify the chemicals compared with Triage^®, which can detect only the metabolized products. Moreover, since HPLC has begun use in our institution, the percentages of detection of chemical materials has elevated more than 25%. However, HPLC takes a long time to get the results, at much expense and requires more technical skills. Therefore, to improve the diagnosis for intoxication patients in critical cases, we should examine with both HPLC and Triage^®. But first, Triage^® should be done and, if its result is negative, afterwards HPLC should be carried out. Furthermore, it was not able to detect around 20% using both HPLC and Triage^®. This result suggests we have to take into consideration HPLC is not enough equipment for all chemical materials and we should consider the countermeasure for negative materials.