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

A need has been recognized for a safe and effective induction for patients undergoing elective renal transplantations. We have evaluated the effect of propofol (injection rate; 50 mg/min, average dosage; 2.28+/-0.08 mg/kg, n=10) on a cardiovascular stability compared with that of thiopental (injection rate; 100 mg/min, average dosage; 5.22+/-0.18 mg/kg, n=10) as an induction agent. Blood pressure and heart rate as cardiovascular parameters were checked before induction(control), one, two, three minutes after induction, before and after orotracheal spray of lidocaine, and immediately, one and two minutes after endotracheal intubation. The results were as follows: 1) There were no significant cardiovascular changes in the propofol group during the whole induction period. 2) In the thiopental group, diastolic blood pressures checked just after intubation, which were 120.20+/-7.79 mmHg, were significantly higher than those of one or two minutes after induction, which were 86.30+/-4.36, 88.40+/-3.85 mmHg, respectively. The above results suggest that intravenous propofol (2.0~2.5 mg/kg) is a safe and effective induction agent for renal recipients.
Blood Pressure ; Heart Rate ; Humans ; Intubation ; Intubation, Intratracheal ; Kidney Transplantation ; Kidney* ; Lidocaine ; Propofol* ; Thiopental

BACKGROUND: In the previous studies, remifentanil reduces the hemodynamic change induced by endotracheal intubation. We studied the optimal effect site concentration of remifentanil for endotracheal intubation using light wand. METHODS: Sixty ASA 1 or 2 patients scheduled for elective surgery under general anesthesia were classified in three groups according to the TCI (target controlled infusion) dose of remifentanil. Each group was administered 4microgram/ml of propofol TCI, rocuronium, with 2 ng/ml (group 1), 4 ng/ml (group 2), 6 ng/ml (group 3) of remifentanil TCI. Blood pressure, heart rate and bispectral index score were measured before induction, 3 minutes after remifentanil and propofol TCI, after endotracheal intubation using light wand, and 3 minutes after endotracheal intubation. Statistical analysis was done for comparison of time and dose dependant change among the groups. RESULTS: After endotrachal intubation, blood pressure and heart rate were significantly increased in group 1, and decreased in group 2 and 3. 3 minute after endotracheal intubation, heart rate significantly decreased in group 3, but there were no changes in group 2. CONCLUSIONS: The spontaneous BRS was decreased during ketamine induction of general anesthesia. These results suggest that anesthesia induction with ketamine impairs baroreflex control of heart rate, which may provoke hemodynamic instability.
Anesthesia ; Anesthesia, General ; Baroreflex ; Blood Pressure ; Heart Rate ; Hemodynamics* ; Humans ; Intubation ; Intubation, Intratracheal* ; Ketamine ; Propofol

BACKGROUND: Epinephrine is commonly used to reduce bleeding by constriction of nasal vessels in endoscopic sinus surgery. However, when it absorbs to other organs systemically, tachycardia and hypertension may occur and result in more bleeding. This study is performed to evaluate the dose response effects of remifentanil infusion to suppress these adverse responses without delaying emergence. METHODS: Sixty healthy patients who scheduled for endoscopic sinus surgery were randomly allocated into three groups by the dose of remifentanil infusion. For induction and maintenance of anesthesia, 0.05, 0.15, 0.25microgram/kg/min of remifentanil and 3.5microgram/ml of intravenous propofol by TCI were infused to each group. Systolic and diastolic blood pressure, heart rate and bispectral index were measured for 15 minutes at the 1 minute intervals after nasal packing of epinephrine. RESULTS: Systolic and diastolic blood pressure in R0.15 and R0.25 group were significantly lower compared to R0.05 group during 9 to 12 minutes after epinephrine packing, but heart rate and bispectral index were not significantly different among the groups. The frequency of hypotension and bradycardia were significantly higher in R0.25 than R0.05 and R0.15. CONCLUSIONS: Continuous infusion of 3.5microgram/ml of propofol with 0.15microgram/kg/min of remifentanil attenuate hypertension and tachycardia induced by epinephrine with little side effects.
Anesthesia ; Blood Pressure ; Bradycardia ; Constriction ; Epinephrine* ; Heart Rate ; Hemodynamics* ; Hemorrhage ; Humans ; Hypertension ; Hypotension ; Propofol ; Tachycardia

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