Abstract
Abnormally high chloride concentration has been occasionally observed in the sera of patients when examined by a Stat/Ion system in which an ion-selective electrode technique is used. One of the causes is presumably the interference of medicaments on chloride electrode. The purpose of the present communication is to identify the medicaments which may interfere with the determination of chloride levels in the serum.
Aliquots of the samples of the sera from the same patients were examined by the ion-selective electrode technique and by Schales-Schales' method. In ten patients (most of the samples were taken several days after operation when the patients were in a serious condition), a marked discrepancy in the chloride values was observed between the above two methods. The medicaments, which were administered during the period in which the chloride concentration was high, was picked up from chart of the above ten patients. Drugs thus selected were added to the pooled serum and the chloride concentration was measured by the above two methods. It was found that the chloride electrode showed a high response to the following six drugs,(a) timepidium bromide (Sesden),(b) butylscopolamine bromide (Buscopan),(c) neostigmine bromide (Vagostigmin),(d) propanthelin bromide (Methaphyllin),(e) composite preparation of salicylate sodium, calcium bromide and dextrose (Salbro) and (f) thiosulfate sodium.
When three healthy volunteers of 3 groups received (a),(b) or bromhexine-HCl (Bisolvon, having bromine in its aromatic nucleus), respectively, of a regular therapeutic dose, no remarkable changes in serum chloride concentration were observed in any groups.
Animal experiments were then carried out as follows. Rats were received orally a single large dose of 300mg/kg of (a) through a gastric tube under the general anesthesia using ethyl ether. A marked difference in serum chloride concentration was observed in between the values just before and one hour after administration, as determined by the Stat/Ion system.
The ion-selective electrode of silver-chloride is not specific to chloride ion. It responds not only to Cl-, but also to Br-, I-, CN-, Fe(CN)3-6, Fe(CN)4-6, SCN-, S--, S2O3--, and to the compounds which contain SH group, such as glutathione and L-cysteine. The disturbance of the silver-chloride electrode with the presence of SH group was not confirmed until today.
There will be an increasing demand for the use of the ion-selective electrode technique for thefollowing reasons: 1) there is a necessity of repeated electrolyte determinations in emergency situation such as post-operative stage, 2) this technique is rather simple and 3) this technique causes no environmental pollution.
However it is to be emphasized that the silver-chloride electrode which currently in use be improved or replaced with one of a new type.
