The changes of propofol concentration in human cerebrospinal fluid after drug infusion.
OBJECTIVE
Investigation of the propofol concentration changes in cerebrospinal fluid (CSF) after the termination of the drug infusion.


METHODS
Nine patients (American Society of Anesthesiologists classes I-III) scheduled for elective intracranial procedures were studied. Propofol was applied in the form of target control infusion. During anesthesia, fractional doses of fentanyl and cisatracurium were administered as necessary. After tracheal intubation, the lungs were ventilated to achieve normocapnia with an oxygen-air mixture (fraction of inspired oxygen = 0.33). Arterial blood and CSF samples (from an intraventricular drain) were taken simultaneously at the end of propofol infusion and then at 15, 30, 45, 60, 90, and 120 minutes after the end of infusion.


RESULTS
A pronounced decrease of the anesthetic concentration in plasma (P < 0.001) was observed during the first 15 minutes after infusion termination, followed by further yet slower decrease of the drug concentration. At the end of propofol infusion, the concentration of propofol in CSF was 65.59 ng/mL (SD, 26.91 ng/mL) and remained almost stable for approximately 30 minutes; afterward, a slow decrease of CSF propofol concentration was observed.


CONCLUSIONS
The statement that CSF can be regarded as a significant route for drugs delivery to the brain is disputable for propofol. The obtained results show that, in contrast to the situation from induction of anesthesia, back transport of the drug from CSF to blood is markedly slower, supporting the thesis about propofol transport from blood to CSF by passive diffusion.
Dawidowicz
Andrzej L
AL
Department of Chromatographic Methods, Faculty of Chemistry, Maria Curie-Sklodowska University, Lublin, Poland. dawid@hermes.umcs.lublin.pl
Kalitynski
Rafal
R
Mardarowicz
Marek
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000097:blood / Q000134:cerebrospinal fluid*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D015742:Propofol / Q000008:administration & dosage / Q000097:blood / Q000134:cerebrospinal fluid*; D013997:Time Factors
D018686:Anesthetics, Intravenous; D015742:Propofol