Intensive Care of Acute Poisoning - A. V. Hovenko 2010

Modern approaches to the diagnosis of acute poisoning
Laboratory diagnostic methods for acute poisoning

Laboratory toxicological Diagnostics of poisonings has three main areas:

1) specific toxicological testing for the emergency detection of toxic substances in biological Body Fluids;

2) specific testing to determine characteristic Changes in the Biochemical Composition of Blood;

3) nonspecific biochemical tests to diagnose the severity of toxic damage to Liver, Kidney, and other organ Functions.

Modern laboratory and instrumental rapid Methods for determining toxic substances in biological environments (blood, urine, dialysate solutions) must deliver results within the shortest possible time (1-2 hours) and be sufficiently accurate. These requirements are met by Thin-Layer Chromatography, Gas-Liquid Chromatography, and spectrophotometry. The choice of method is primarily determined by the PHYSICOCHEMICAL PROPERTIES OF the toxic substances causing the poisoning, as well as the methods used to extract them from the biological sample provided for analysis.

Chemical and toxicological screening is performed in the following sequence.

1. At the pre-hospital stage, the emergency medical team collects physical evidence: medications, suspicious liquids. When performing gastric lavage in patients with unknown poisoning, it is essential to collect the first portion of the wash Water (100-150 ml).

If Carbon monoxide poisoning is suspected, a blood sample must be taken.

2. In the hospital, blood and urine samples are collected prior to THE START OF infusion therapy.

3. In the hospital, the toxicologist, based on clinical symptoms, instrumental data, and physical evidence, proceeds with the search and identification of toxic substances.

4. The Isolation of the toxic substance from biological material is a crucial stage of chemical and toxicological analysis. The following Procedures are used for this purpose:

a) extraction of the poison with organic Solvents (barbiturates, Alkaloids, organophosphorus insecticides); in some cases, purification of the isolated substance via back-extraction and thin-layer chromatography is required;

b) distillation (alcohols, organic solvents, etc.);

c) mineralization (metals);

d) destruction (heavy metals).

5. The next stage of chemical and toxicological analysis is proving the presence of the toxic substance in the biological material using Chemical Reactions or instrumental methods (thin-layer and gas-liquid chromatography, spectrophotometry).

6. Quantitative determination of toxic substances in the sample using gas-liquid chromatography.

7. During the chemical and toxicological analysis of an unknown poison, urine samples are first examined using chromatography of alkaline, neutral, and acidic extracts, as well as volatile substances (when identifying alcohol and its surrogates), along with various chemical reactions.

8. Upon the detection of toxic substances from any group, a quantitative analysis is performed.

9. The final Diagnosis of poisoning is established by the toxicologist based on the results of the chemical and toxicological analysis and clinical examination data, taking mandatory account of specific and nonspecific biochemical test results. The toxicological laboratory report and the toxicologist's diagnosis frequently serve as legal documents in criminal proceedings and are reviewed in court hearings.