Suicide by self-administration of pethidine, propofol and anxiolytics : a case report

Proença, Paula; Castanheira, Alice; Castanheira, Fernando; Monteiro, Carla; Simoes Da Silva, Beatriz; Franco, João Miguel; Corte Real, Francisco

http://hdl.handle.net/10400.26/53942

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Authors

Proença, Paula

Castanheira, Alice

Castanheira, Fernando

Monteiro, Carla

Simoes Da Silva, Beatriz

Franco, João Miguel

Corte Real, Francisco

Abstract(s)

Background and aim: Recreational use of anesthetic and sedative agents in health care practitioners is becoming an increasing problem due to its easy availability and, therefore, they become vulnerable to misusing or abusing of these drugs. The authors present a fatal case involving a a 50-year-old man, nurse, found dead in a hospital room, in supine position, with intravenous access devices in the forearm that were attached to two packages of saline solutions. Some empty packages were close to the victim. A white viscous fluid found at the death scene was send to analysis. The expert's investigation at the scene indicated possible propofol poisoning. Methods: The blood samples were initially subjected to a qualitative analysis. A systematic toxicological drug screening was carried out in blood with a combination of enzyme immunoassays (ELISA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Femoral blood alcohol concentration was measured by gas chromatography with headspace (GC/FID) technique. Due to suspected propofol intoxication, a specific analytical methodology was developed in order to detect and quantify this substance in the postmortem samples. Chromatographic analysis of propofol was preceded by protein precipitation of 0.1 mL of blood samples with acetonitrile. Chromatographic separation was achieved with a reversed-phase column, using a gradient elution of 2 mM aqueous ammonium formate (0.1% formic acid), and 2mM ammonium fluoride in methanol, at a flow rate of 0.4 mL/min, with a run time of 10 minutes. Results and discussion: Toxicological results revealed the presence of the anesthetic (propofol) in femoral blood (33.5 mg/L) and heart blood (113.3 mg/L), and also in the white viscous fluid found at the death scene. The remaining laboratory analyses revealed the presence of nordiazepam, temazepam and metoclopramide in therapeutic concentrations, but toxic blood concentrations of midazolam (1473 μg/L), diazepam (5182 μg/L) and pethidine (8622 μg/L). The blood alcohol analysis result was positive (0.18 g/L) as well as positive for opiates (morfine < 25 μg/L). Pesticides were not present in the analysed samples. Conclusion: The development of the method for confirmation and quantification of the anesthetic propofol was crucial given the suspicion of poisoning by this substance. However, laboratory analysis has also revealed the simultaneous presence of an opioid analgesic agent (pethidine) and anxiolytics in high blood concentrations. These findings have allowed to identify a case where several drugs were abused and whose synergy of effects and intoxication, that were not considered at first, were lately found to have contributed to the medico-legal etiology of suicide.