Fig. 33.1 Which drugs?
Drug Testing Questions
How does substance abuse affect anesthesiology as a specialty?
What test would you order for suspected fentanyl substance abuse in your patients?
What test would you order for suspected cocaine substance abuse in your patients?
How do you test for marijuana drug use in your patients?
According to the American College of Surgeons certified Level I Trauma Centers, what percentage of patients screened are positive for both alcohol and illicit drug misuse?
How do you group illicit drugs and what are their anesthetic implications?
Eighty percent of anesthesia residency programs have at least one resident with substance abuse. One to two percent of anesthesia residents have a problem with substance abuse. The Massachusetts General Hospital has instituted a preplacement (preemployment) and post-employment random urine testing in an attempt to lower the incidence of substance abuse among anesthesia residents . Twenty-nine percent of anesthesia residents relapse after being allowed to return/continue in an anesthesia residency program. For residents that are allowed to return to their residency program, the initial presentation is death (10%). Forty-three percent of program directors feel that residents in recovery should be allowed to attempt reentry, while 30% feel that they should not .
Fentanyl can be detected by radioimmunoassay or more selective gas chromatographic techniques. Urine and blood screening involving a novel enzyme-linked immunosorbent assay (ELISA) coupled with nanoparticles for fentanyl detection has the advantage of being simple, sensitive, inexpensive, and capable of detecting metabolites . Fentanyl concentrations as low as 5 pg/well can be detected in urine and serum samples.
Urine radioimmunoassay test is the initial screening test for cocaine abuse and is positive for up to 72 h after exposure. Benzoylecgonine is the main cocaine urine metabolite tested in cocaine drug screening . Gas chromatography coupled with mass spectrometry (GC-MS) or liquid chromatography coupled with a mass spectrometry (LC/MS) is more sensitive and sophisticated than immunoassay and can be done for confirmation of various drugs and their metabolites including cocaine. The window of testing is 1–3 days for urine testing. Although hair testing is the most sensitive for cocaine and has the widest detection window indicating chronic use, it is not done routinely compared to urine.
Urine is the preferred medium to test for marijuana use because of higher concentrations, longer detection time of metabolites, ease of sampling, and higher sensitivity compared to blood . The major metabolite tested in marijuana use is tetrahydrocannabinol (THC) and carboxy tetrahydrocannabinol (THCCOOH). The detection window for urine testing is 10 h for THC and 25 days for THCCOOH. While immunoassay is adequate for preliminary testing, advanced chromatographic techniques are used for quantitation of levels.
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