|SOFT - TIAFT 1998||Poster Session 3||Thursday October 8, 1998|
A CASE OF PROPOFOL ABUSE|
Karla A. Moore, Robert Jones, Barry Levine, and Michael L. Smith
Division of Forensic Toxicology, Armed Forces Institute of Pathology, 1413 Research Blvd., Rockville, MD 20850, USA
|Propofol (2,6-diisopropylphenol) is a drug used as an anesthetic agent. It is structurally unrelated to other common anesthetic agents such as opioids, barbiturates, benzodiazepines and halogenated liquids. An initial inducing dose is given to the patient and is followed by an infusion to maintain anesthesia. Blood propofol concentrations associated with anesthesia range from 2 to 4 mg/L.
In the presented case, a 50 year-old white female surgical nurse was found unconscious in a bathroom near her duty station at a major military medical institution. A syringe was found in her arm. In her purse were found 5 empty and 1 unused vials of Diprivan®. Other empty vials were found among her possessions. The patient had a medical history of migraine headaches and insomnia, but no history of depression or other psychiatric disorders. A blood specimen was collected from the patient and sent to the Division of Forensic Toxicology for comprehensive testing for therapeutic and abused drugs.
No common therapeutic or abused drugs were detected in the blood specimen using a combination of radioimmunoassay and gas chromatography-nitrogen phosphorus detection. Since propofol does not contain a nitrogen atom, a gas chromatography/mass spectrometry (GC/MS) method was developed to identify and quantify propofol in the blood. To 2 mL blood were added 2 mL saturated borate buffer, 40 µg methylphenidate (internal standard, I.S.) and 0.15 mL chloroform: ethyl acetate (70:30). After mixing and centrifuging, 2 µL were injected into the GC/MS. A 30 m x 0.53 mm ID DB-5 column was used to achieve analytical separation. The oven temperature began at 100oC for one minute and increased at 30oC to 270oC. Three ions at m/z = 163, 178 and 117 were monitored for qualitative identification; m/z = 163 and 84 (I.S.) were used for quantification. In this case, the blood propofol concentration was 0.24 mg/L. A previously reported propofol fatality had a propofol concentration of 0.22 mg/L.