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*

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*

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

BACKGROUND: Remifentanil is an ultra-short-acting mu opioid receptor agonist. However, there are few reports of its use in children. Therefore, this study compared propofol-remifentanil anesthesia (PR) with a desflurane-N2O anesthesia (D) in children. METHODS: One hundred children (5-12 years), who were scheduled for a tonsillectomy, were randomly assigned to either Group PR (n=50) or Group D (n=50). After inducing anesthesia with propofol and rocuronium, group PR was maintained with an infusion of propofol and remifentanil. Group D was maintained with desflurane. At the end of surgery all the anesthetics were terminated without tapering. The systolic and diastolic blood pressure, and heart rate were measured upon arrival at the operation room, after induction, after intubation, at the beginning of the operation, 5, 10, 20 minutes after beginning of surgery and the end of anesthesia. RESULTS: There was a significantly lower heart rate in group PR than in group D but there was no significant difference in blood pressure between the two groups. CONCLUSIONS: In children, propofol-remifentanil anesthesia is a well-tolerated method of anesthesia, with a lower heart rate compared with desflurane-N2O based anesthesia.
Anesthesia* ; Anesthetics ; Blood Pressure* ; Child ; Heart Rate* ; Heart* ; Humans ; Intubation ; Propofol ; Receptors, Opioid, mu ; Tonsillectomy*

BACKGROUND: Midazolam is often used as an anxiolytic premedication before surgery, but it is difficult and complex to assess its effect. This study evaluated the bispectral index as an objective indicator of midazolam premedication and the relation of cardiovascular response to anesthetic induction. METHODS: Forty patients (aged 20 to 60 and in ASA class I or II) to undergo simple elective surgery under general anesthesia entered the study. The patients were divided into the midazolam group (n = 20) that received midazolam (0.08 mg/kg IM) and glycopyrrolate (0.2 mg IM) premedication, and the control group (n = 20) that received glycopyrrolate (0.2 mg IM) only. Then, anesthetic induction (fentanyl 1 microgram/kg, propofol 2 mg/kg, succinylcholine 1 mg/kg) was done. The bispectral index of the electroencephalogram, blood pressure, and heart rate were measured under unanesthetized conditions, after fentanyl, propofol injection, and intubation. RESULTS: The bispectral index was significantly lower in the midazolam group as compared with the control group before anesthetic induction, after fentanyl injection, and intubation. Blood pressure was not significantly different in the two groups. Heart rate was significantly lower in the midazolam group compared with the control group before anesthetic induction and after fentanyl injection. CONCLUSIONS: Midazolam-premedicated patients appear to maintain stable hemodynamics during anesthetic induction and intubation. The bispectral index can be objectively used in midazolam-premedicated patients when evaluating the degree of sedation. (Korean J Anesthesiol 2000; 38: 947~953)
Anesthesia, General ; Blood Pressure ; Electroencephalography ; Fentanyl ; Glycopyrrolate ; Heart Rate ; Hemodynamics ; Humans ; Intubation ; Midazolam* ; Premedication* ; Propofol ; Succinylcholine

BACKGROUND: Remifentanil is a new member of fentanyl family and a short-acting, esterase-metabolized opioid.This study compared the perioperative characteristics of a remifentanil infusion with those of fentanyl bolus administration as an adjuvant to propofol infusion for the anesthetic management of patients undergoing ureteroscopic lithotripsy. METHODS: Eighty patients were randomly assigned to receive either remifentanil target controlled infusion (R group, effect-site concentration of 4.0 ng/ml for induction followed by 2.0 ng/ml) or fentanyl bolus (F group, 2.0microgram/kg before induction).All patients received propofol infusion as the part of the induction and maintenance.We investigated recovery profiles, adverse events and the ease of insertion of laryngeal mask airway (LMA) between the two groups.Heart rate (HR) and mean blood pressure (MBP) were also compared at baseline (T0), loss of consciousness (T1), insertion of LMA (T2), beginning and end of operation (T3, T4) and removal of LMA (T5). RESULTS: The time from the end of anesthesia to spontaneous respiration, eye opening and LMA removal were significantly shorter for patients receiving remifentanil than for those receiving fentanyl.HR at T3 and T4 were lower in the R group than in the F group.Aldrete recovery score, time to discharge from recovery ward, the ease of insertion of the LMA, MAP and adverse events did not differ significantly between the two groups. CONCLUSIONS: Target controlled infusion of remifentanil combined with propofol can significantly shorten the early recovery time than fentanyl bolus administration without increasing adverse events in patients undergoing ureteroscopic lithotripsy.
Anesthesia ; Blood Pressure ; Eye ; Fentanyl ; Humans ; Laryngeal Masks ; Lithotripsy ; Piperidines ; Propofol ; Respiration ; Unconsciousness

BACKGROUND: To analyze how lidocaine 40 mg mixed prevents injection pain of propofol affects the onset time of rocuronium, tracheal intubating conditions and intubation related hemodynamic changes. METHODS: This study consisted of 70 patients with an American Society of Anesthesiologists (ASA) physical status class 1 or 2 for general anesthesia. All the patients were randomly allocated into two groups: propofol 2 mg/kg plus normal saline 2 ml (Group C) and propofol 2 mg/kg plus 2% lidocaine 40 mg (Group L). Each group was administrated intravenously during induction and the patient was intubated 1 minute after an injection of 0.6 mg/kg of rocuronium. The time at disappearance of the first twitch and intubation scores were recorded. Also, blood pressure and heart rate were measured at the baseline, after intravenous injection of propofol, before intubation, and at 0, 1, 2, 3 and 5 minutes after intubation. RESULTS: There were no significant differences between group C and L (P > 0.05). CONCLUSIONS: 40 mg of lidocaine mixed with propofol to prevent injection pain did not affect the onset time of rocuronium, intubating conditions and intubation related hemodynamic changes.
Androstanols ; Anesthesia, General ; Blood Pressure ; Heart Rate ; Hemodynamics ; Humans ; Injections, Intravenous ; Intubation ; Lidocaine ; Neuromuscular Blockade ; Propofol