BACKGROUND: This study compared the hemodynamic response and recovery profile of remifentanil-sevoflurane anesthesia for a pediatric tonsillectomy with that of remifentanil-propofol anesthesia. METHODS: Fifty healthy children (4-10 yr) undergoing a tonsillectomy were randomly assigned to one of two groups. Anesthesia was induced with remifentanil 1 mcg/kg over 1 min, propofol 2 mg/kg, and rocuronium 0.8 mg/kg. Anesthesia was maintained with remifentanil 0.25 mcg/kg/min and propofol 6 mg/kg/h, or remifentanil 0.25 mcg/kg/min and sevoflurane 1.0 vol%. The propofol and sevoflurane dose was kept unchanged, and remifentanil was titrated according to the hemodynamic response. The perioperative hemodynamics, recovery time, and side effects were assessed. RESULTS: Remifentanil-based anesthesia with propofol or sevoflurane resulted in stable hemodynamics, but sevoflurane was associated with a significantly lower systolic blood pressure. The recovery times were similar for spontaneous ventilation, extubation, eye opening, orientation, and full recovery in both groups. The incidence of side effects was similar in both groups. CONCLUSIONS: Remifentanil/sevoflurane is as equally effective as remifentanil/propofol in pediatric patients. The hemodynamic stability is appropriate and the recovery from anesthesia is rapid.
Anesthesia* ; Blood Pressure ; Child ; Hemodynamics ; Humans ; Incidence ; Propofol ; Tonsillectomy* ; Ventilation

BACKGROUND: Induction of anesthesia with propofol commonly associated with reduction in systemic arterial pressure, especially in elderly and high risk patients. This reduction is influenced by the dose and rate of propofol injection. The aim of this study was to examine the effect of different injection rate of propofol on vital signs, dose requirement and induction time during induction period. METHODS: Unpremedicated one hundred and twenty ASA physical status I and II patients aged 20~60 years scheduled for elective surgery were randomly allocated into one of four (150, 300, 600, 1200 ml/hr) groups according to speed of injection of propofol during induction period. Loss of verbal contact was taken as the end-point of induction. Vital signs, SpO2, dose requirement of propofol and induction time were checked. RESULTS: As the injection rate of propofol became slower, there were significant reduction in induction dose and increase in induction time (p<0.05). For example, induction dose and time were 1.82 mg/kg, 223 +/- 58 sec in 150 ml/hr group and 3.14 mg/kg, 50 +/- 11 sec in 1200 ml/hr group, respectively. Also, decrease in systolic and diastolic pressure were less marked at lower injection rates. CONCLUSIONS: Slower injection of propofol produces less vital sign changes and dose requirement for the induction of anesthesia.
Aged ; Anesthesia* ; Arterial Pressure ; Blood Pressure ; Humans ; Propofol* ; Vital Signs*

BACKGROUND: The effect site is the theoretical compartment in which a drug exerts its action and thus the concentration at this site is a direct determinant of a drug,s effect. This study was performed to compare effect site targeting with plasma targeting with regard to induction phenomena and vital sign changes using propofol target controlled infusion (TCI). METHODS: Forty patients were randomly assigned to one of two groups. Groups were defined as propofol administered via TCI to either a target plasma propofol concentration (group P) or to a target effect site (group E) propofol concentration. We used Master TCI for plasma targeting and a stelpump program for effect site targeting. The concentration targeted for all subjects was 5.7 microgram/ml. We compared the time to loss of consciousness, change of concentration, BP and pulse pressure between groups until the effect site concentration was reached at 5.7 microgram/ml. RESULTS: The median time to LOC in group P was 58.1 +/- 11.8 s and 35.8 +/- 7.9 s in group E (P <0.05). The mean time to achieve the effect site concentration of 5.7 microgram/ml was 18.5 +/- 0.1 min in group P and 3.6 +/- 0.1 min in group E (P < 0.05). Systolic and diastolic blood pressure showed significant changes in group E. CONCLUSIONS: We concluded that anesthetic induction time can be significantly reduced when the effect site concentration is targeted. However, we recommended effect site targeting in anesthesia induction with propofol TCI only in cases of healthy young patients because of possible undesirable hemodynamic changes.
Anesthesia ; Blood Pressure ; Hemodynamics ; Humans ; Plasma ; Propofol ; Unconsciousness ; Vital Signs

BACKGROUND: Propofol is a good choice for elderly patents because it produces rapid onset and quick recovery with few side effects. Propofol produces dose-dependent cardiovascular depression. This effect is more pronounced in elderly patients during induction and can be minimized by a slow injection. The aim of this study was to determine the appropriate induction dose of propofol using a slower infusion rate for elderly patients to obtain desirable sedation and hypnotic conditions with minimal hemodynamic changes. METHODS: Thirty-nine patients aged over 70 years were assigned to receive a propofol infusion of either 1.5 mg/kg (n = 21, Group 1) or 2.0 mg/kg (n = 18, group 2). The infusion rate was 20 mg/kg/hr. The systolic and diastolic pressure, heart rate, BIS and modified observers assessment of the alertness/sedation scale (OAA/S) were measured before the induction (baseline), after the propofol infusion, as well as immediately, 3 and 5 minutes after intubation. RESULTS: The systolic pressure decreased significantly after the propofol infusion in both groups (group 1: 17%, group 2: 25%) but there were no significant differences between them. The BIS values after the propofol infusion and intubation were 67.1 +/- 12.6 and 62.3 +/- 12.7 in group 1, 49.6 +/- 11.1 and 51.7 +/- 11.7 in group 2, respectively which showed significant differences between the groups. CONCLUSIONS: When 2.0 mg/kg of propofol is administrated to elderly patients, a slower infusion rate is more appropriate for maintaining the desirable sedation and hypnotic conditions and cause no significant hemodynamic changes.
Aged* ; Blood Pressure ; Depression ; Heart Rate ; Hemodynamics* ; Humans ; Intubation ; Propofol*

This study aimed to establish a new propofol target-controlled infusion (TCI) model in animals so as to study the general anesthetic mechanism at multi-levels in vivo. Twenty Japanese white rabbits were enrolled and propofol (10 mg/kg) was administrated intravenously. Artery blood samples were collected at various time points after injection, and plasma concentrations of propofol were measured. Pharmacokinetic modeling was performed using WinNonlin software. Propofol TCI within the acquired parameters integrated was conducted to achieve different anesthetic depths in rabbits, monitored by narcotrend. The pharmacodynamics was analyzed using a sigmoidal inhibitory maximal effect model for narcotrend index (NI) versus effect-site concentration. The results showed the pharmacokinetics of propofol in Japanese white rabbits was best described by a two-compartment model. The target plasma concentrations of propofol required at light anesthetic depth was 9.77±0.23 μg/mL, while 12.52±0.69 μg/mL at deep anesthetic depth. NI was 76.17±4.25 at light anesthetic depth, while 27.41±5.77 at deep anesthetic depth. The effect-site elimination rate constant (ke0) was 0.263/min, and the propofol dose required to achieve a 50% decrease in the NI value from baseline was 11.19 μg/mL (95% CI, 10.25-13.67). Our results established a new propofol TCI animal model and proved the model controlled the anesthetic depth accurately and stably in rabbits. The study provides a powerful method for exploring general anesthetic mechanisms at different anesthetic depths in vivo.
Anesthetics, Intravenous ; blood ; pharmacokinetics ; Animals ; Drug Monitoring ; Infusions, Intravenous ; Models, Statistical ; Propofol ; blood ; pharmacokinetics ; Rabbits ; Software

OBJECTIVE: A rapid and selective method has been developed for the determination of propofol in blood by gas chromatography-mass spectrometry (GC-MS). METHODS: The blood was extrasted with the solution of internal standard, the extracted residue was analyzed by gas chromatography-mass spectrometry using selected-ion monitoring mode. RESULTS: The linear range was 0.1-10 microg/mL. The coefficient(R2) was 0.993 1. The detection limit was 0.05 microg/mL. CONCLUSION The method is simple and rapid, offering superior sensitivity and selectivity for propofol. The method can be used successfully during clinical and forensic toxicology.
Anesthetics, Intravenous/blood* ; Gas Chromatography-Mass Spectrometry/methods* ; Humans ; Propofol/blood* ; Reproducibility of Results ; Sensitivity and Specificity

OBJECTIVETo investigate the effect of propofol at doses for different anesthesia depths on γ-aminobutyric acid (GABA) in different cerebral regions at propofol uptake equilibrium in dogs.

METHODSTwelve 12-18-month-old healthy hybrid dogs weighing 10-12 kg were randomly divided into light anesthesia group (n=6) and deep anesthesia group (n=6) with a single bolus dose of propofol (5.5 and 7.0 mg/kg, respectively) completed in 15 s followed by intravenous propofol infusion at a constant rate (55 and 70 mg·kg(-1)·h(-1), respectively). Blood samples (2 ml) were taken from the internal carotid artery and jugular vein to measure plasma propofol concentrations 50 min after the start of the infusion. The dogs were then sacrificed and tissues were taken from different brain regions and the cervical cord to measure GABA concentrations using high-pressure liquid chromatography (HPLC).

RESULTSThe plasma propofol concentrations in internal carotid artery and jugular vein were similar in both light anesthesia group (3.00 ± 0.31 and 3.10 ± 0.51 µg/ml, respectively, P>0.05) and deep anesthesia group (6.41 ± 0.05 and 6.40 ± 0.11 µg/ml, respectively, P>0.05). GABA concentrations in the brain regions were significantly higher in deep anesthesia group than in light anesthesia group (P<0.05). The dorsal thalamus and hypothalamus showed greater GABA variations [(83.83 ± 2.230%) and (85.83 ± 1.72)%] compared to other brain regions at different anesthesia depths (P<0.05).

CONCLUSIONSIn both groups, plasma propofol concentrations in the internal carotid artery and internal jugular vein reach equilibrium at 50 min of propofol infusion. The variation of GABA is associated with the anesthesia depth of propofol, and GABA variation in the dorsal thalamus and hypothalamus plays an important role in propofol anesthesia.

Anesthetics, Intravenous ; pharmacokinetics ; Animals ; Brain ; metabolism ; Dogs ; Female ; Male ; Propofol ; blood ; pharmacokinetics ; gamma-Aminobutyric Acid ; metabolism

A possibility to use the Membrane-Introduction Mass Spectrometry (MIMS) with membrane separator interface has evolved into a powerful method for measurement of anaesthetic agents absolute concentration in blood plasma and cerebrospinal fluid for the study of blood-brain barrier (BBB) properties. Recent advanced a new membrane material was used for drug concentration measurement in biologic fluids. A hydrophobic membrane was used in the interface to separate anaesthetic agents from biological fluids: inhalational anaesthetic desflurane,hypnotic propofol, analgesic fentanyl. The selective detection of volatile anesthetic agents in blood does not require long-term sample processing before injecting the sample into mass-spectrometer interface, in contrast to chromatographic methods. Mass-spectrometric interface for the measurement of anaesthetic agent concentration in biological fluids (blood plasma and cerebrospinal fluid) is described. Sampling of biological fluids was performed during balanced inhalational (desflurane, fentanyl) anaesthesia and total intravenous (propofol, fentanyl) anaesthesia.
Anesthesia ; Anesthetics ; Blood-Brain Barrier ; Cerebrospinal Fluid* ; Fentanyl* ; Mass Spectrometry* ; Membranes ; Plasma* ; Propofol*

BACKGROUND: Sevoflurane has been reported to potentiate the effect of rocuronium. We compared the effect of sevoflurane and propofol on intubating conditions and their corresponding hemodynamic changes, and also compared the intubation conditions at different intubation timing using the rocuronium. METHODS: Sixty patients were randomized into four groups: group P (P-60, P-90) received 10 mg/kg/hr of propofol after 2 mg/kg of bolus injection; group S (S-60, S-90) were inhaled with 8 vol% sevoflurane after injection of 50 mg of thiopental sodium. Intubation was attempted at either 60 seconds (P-60, S-60) or 90 seconds (P-90, S-90) after the rocuronium administration. Intubation conditions were assessed and evaluated as excellent, good, poor and inadequate. Single twitch responses were measured at every 30 seconds after rocuronium administration. Blood pressure and heart rate were measured before induction, before intubation and immediately after intubation. RESULTS: Excellent and good intubation conditions were obtained in 60% (n = 9) of group P-60, 73% (n = 11) of group S-60, 92% (n = 14) of group P-90 and 100% (n = 15) of group S-90. Single twitch responses were fewer in group P-90 and S-90 compared to those in group P-60 and S-60 (P < 0.01). Blood pressure and heart rate after intubation were elevated in all four groups. CONCLUSIONS: Intubation conditions were not significantly different between inhalation of sevoflurane and intravenous administration of propofol when using rocuronium. Prolonged interval between rocuronium administration and intubation resulted in improved intubation conditions.
Administration, Intravenous ; Blood Pressure ; Heart Rate ; Hemodynamics ; Humans ; Inhalation ; Intubation* ; Propofol ; Thiopental

BACKGROUND: We performed a prospective, randomized, and controlled trial to evaluate the effect of an intravenous fentanyl and propofol on the variation in BIS level associated tracheal suction. METHODS: Thirty ICU patients intubated or tracheostomized were randomly allocated to control and experimental groups. Control group was received saline and experimental groups were received propofol with or without fentanyl intravenously prior to tracheal suction. And then we monitored BIS index, blood pressure, heart rate and SpO2 before, during and after tracheal suction. RESULTS: BIS index was significantly lower in propofol plus fentanyl group than others during experiment (P < 0.05). Heart rate and blood pressure in propofol plus fentanyl group also less increased than those in control or propofol group during tracheal suction (P < 0.05). CONCLUSIONS: These results suggest that co-administration of propofol and fentanyl has more effective than propofol alone in sedation and analgesia of ICU patients during tracheal suction.
Analgesia ; Blood Pressure ; Fentanyl* ; Heart Rate ; Humans ; Propofol* ; Prospective Studies ; Suction*