The effect of positive end-expiratory pressure ventilation on propofol concentrations during general anesthesia in humans

• Published in: Fundamental & clinical pharmacology Vol. 20; no. 5; pp. 489 - 492
• Main Authors: Takizawa, Eri, Ito, Naomi, Ishizeki, Junko, Goto, Fumio, Hiraoka, Haruhiko, Takizawa, Daisuke
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.10.2006; Blackwell
• Subjects: Adult; Anesthesia, General; Anesthetics, Intravenous - blood; Anesthetics, Intravenous - pharmacokinetics; Biological and medical sciences; Cardiac Output; Female; Humans; liver blood flow; Liver Circulation; Male; Medical sciences; Middle Aged; pharmacokinetics; Pharmacology. Drug treatments; Positive-Pressure Respiration; Propofol - blood; Propofol - pharmacokinetics; Human; Digestive system; Liver; General anesthesia; Respiratory system; Blood flow; General anesthetic; Positive pressure; Cardiac output; Hemodynamics; Propofol; Pulmonary ventilation; Respiration; Pharmacokinetics; liver blood flow
• ISSN: 0767-3981; 1472-8206
• DOI: 10.1111/j.1472-8206.2006.00436.x

The present study investigated the effects of positive end‐expiratory pressure (PEEP) on propofol concentrations in humans. Eleven patients undergoing elective surgery were enrolled in this study. Anesthesia was induced with propofol, then maintained using 60% nitrous oxide in oxygen, fentanyl 10–20 μg/kg and continuous infusion of propofol. Vecuronium was used to facilitate the artificial ventilation of the lungs. Propofol was administered to all subjects via target‐controlled infusion to achieve a propofol concentration of 6.0 μg/mL at intubation and 2.0 μg/mL after intubation. Before, during and after PEEP level of 10 cmH2O, cardiac output (CO) and effective liver blood flow (LBF) was measured using indocyanine green as an indicator and blood propofol concentration was determined using high‐performance liquid chromatography. Data are expressed as median and range. After PEEP of 10 cmH2O was applied, CO and effective LBF was significantly decreased from 5.5 (3.8–6.8) L/min to 4.5 (3.2–5.8) L/min (P < 0.05), 0.78 (0.65–1.21) L/min to 0.65 (0.50–0.89) L/min (P < 0.05), respectively. Propofol concentration was significantly increased from 2.21 (1.46–2.63) μg/mL to 2.45(1.79–2.89) μg/mL (P < 0.05). These data indicate that propofol concentrations can be increased by PEEP, suggesting the possibility of overdosing following PEEP.