Clinical chemistry
-
A 27-year-old man with a history of cocaine abuse ingested a large quantity of street cocaine in an apparent suicide attempt. Shortly thereafter, he developed tonic-clonic seizures and became cyanotic. An arterial blood gas sample, collected in the emergency department, appeared chocolate-brown and showed pO2 279 mmHg, pCO2 53 mmHg, and pH 7.15. ⋯ Further testing revealed the presence of benzocaine, a compound known to produce methemoglobinemia. A powder submitted as the "cutting" substance was shown to be benzocaine. When confronted with a possible cocaine overdose (particularly by ingestion), the physician should consider the possible clinical effects of adulterants, especially local anesthetics such as benzocaine.
-
To assess the effect of prolonged administration of midazolam or isoflurane on hepatocellular integrity, we measured the concentrations of glutathione transferase (EC 2.5.1.18) B1 subunit and the activities of alanine aminotransferase (ALT; EC 2.6.1.2) and aspartate aminotransferase (AST; EC 2.6.1.1) in 40 patients who required long-term sedation with low-dose midazolam or isoflurane. Blood samples were collected before and 24 h after the start of the sedation and 0, 24, 72, 120, and 172 h after the last dose. ⋯ The patients who received isoflurane and those who received midazolam showed no significant differences in any of the enzyme tests. We conclude that long-term sedation with midazolam or isoflurane is unlikely to affect hepatocellular integrity.