Summary
Background
Thiopental, as many other centrally acting drugs, can depress the electroencephalogram, so serum levels of these drugs must be well below their therapeutic range for a reliable diagnosis of brain death. While for many of these drugs fast and simple immunossays are available, for thiopental only chromatographic tests are available.
Methods
We compared a high-performance liquid chromatographic method with an ultraviolet detector (HPLCUV) and a gas chromatographic method with a flame ionization detector (GC-FID) for the quantification of serum thiopental.
Results
From January to July 2011, serum samples collected from 25 critically ill patients were processed either by both HPLC-UV and GC-FID for the quantification of serum thiopental. A satisfactory correlation was found between the methods.
Conclusion
Although both methods were reliable, easy to perform and fast enough, the GC-FID method seemed to fit to our needs better than the HPLC-UV method. This was due to the extreme sensitivity of GC in quantifying serum thiopental well below the therapeutic level, and also because GC is easier and faster to perform in a setting which usually needs a rapid turn-around time.
Riassunto
Premesse
Il Tiopentale è in grado di causare, come molti farmaci che agiscono sul sistema nervoso centrale, una profonda depressione fino all’appiattimento dell’elettroencefalogramma. Tale situazione si sostanzia in una difficoltà nella diagnosi di morte cerebrale in soggetti con estese lesioni a carico dell’encefalo, e potenziali candidati al prelievo di organi. Allo stato attuale, per il rilievo del Tiopentale sono disponibili esclusivamente sistemi cromatografici.
Metodi
Questo lavoro descrive la valutazione comparativa fra il metodo gas cromatografico con rilevazione in ionizzazione di fiamma, e il metodo in cromatografia liquida a elevate prestazioni con rilevazione in ultra violetto, allo scopo di valutarne caratteristiche, qualità e adattabilità alle esigenze di supporto al centro di medicina trapiantologica.
Risultati
Dal mese di gennaio al mese di luglio 2011 i sieri di 25 pazienti critici, in osservazione per possibile prelievo di organi a scopo di trapianto, sono stati analizzati sia con il metodo gas cromatografico in uso, che con metodo alternativo in cromatografia liquida a elevate prestazioni. Tra le due metodiche è stata riscontrata una soddisfacente correlazione.
Conclusioni
Entrambi i metodi presi in considerazione si sono dimostrati affidabili e di relativa facilità di esecuzione; tuttavia in base alla nostra esperienza, il metodo gas cromatografico appare più soddisfacente in termini di rapidità di esecuzione e nello stesso tempo sembra particolarmente sensibile per il rilievo di valori decisamente al di sotto dell’intervallo terapeutico. In patologia trapiantologica, è per altro opportuno che vengano utilizzate metodiche con un Turn Around Time (TAT) quanto più breve possibile.
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Colatutto, A., Zaglia, R., Isola, L. et al. Comparison between a high-perfomance liquid chromatographic method and a gas chromatographic method for the quantification of serum thiopental for the diagnosis of brain death in critically ill patients. Riv Ital Med Lab 8, 162–167 (2012). https://doi.org/10.1007/s13631-012-0060-1
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DOI: https://doi.org/10.1007/s13631-012-0060-1
Key words
- Brain death diagnosis
- Flat encephalogram
- High-performance liquid chromatography with ultraviolet detector (HPLC-UV)
- Gas chromatography with flame ionization detector (GC-FID)
- Turn around time (TAT)