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: 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: 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: In endoscopic sinus surgery, visualization of the surgical field is a major concern, as surgical bleeding is the cause of many complications. The purpose of this study was to compare the effects of dexmedetomidine and remifentanil on the visualization of the surgical field in endoscopic sinus surgery. METHODS: Forty-three patients were prospectively enrolled and randomly allocated to the dexmedetomidine or remifentanil group and general anesthesia was induced and maintained using a propofol target-controlled infusion. In the dexmedetomidine group, dexmedetomidine was loaded for 5 min and a continuous infusion was administered. In the remifentanil group, a remifentanil target-controlled infusion was used. After completion of the operation, the satisfaction with the visualization of the surgical field was assessed on a numeric rating scale, from 0 (= worst) to 10 (= best). The mean blood pressure, heart rate, recovery profiles, and postoperative pain score were recorded. RESULTS: Satisfaction score for visualization by numeric rating scale was not significantly different between the two groups (P = 0.95). There were no differences in the mean blood pressure and heart rate. The extubation time was significantly shorter in the dexmedetomidine group (8.4 +/- 1.8 min) than in the remifentanil group (11.9 +/- 5.4 min) (P = 0.04). Except for the extubation time, the recovery profiles of the two groups were comparable. CONCLUSIONS: Continuous infusions of dexmedetomidine provide a similar visualization of the surgical field and hemodynamic stability as remifentanil target-controlled infusions in patients undergoing endoscopic sinus surgery.
Anesthesia, General ; Blood Pressure ; Dexmedetomidine* ; Heart Rate ; Hemodynamics ; Hemorrhage ; Humans ; Pain, Postoperative ; Propofol ; Prospective Studies ; Sinusitis

BACKGROUND: Endotracheal intubation induces clinically adverse cardiovascular changes. Various pharmacological strategies for controlling these responses have been suggested with opioids being widely administered. In this study, the optimal effect-site concentration (Ce) of remifentanil for minimizing hemodynamic responses to fiberoptic nasotracheal intubation was evaluated. METHODS: Thirty patients, aged 18-63 years, scheduled for elective surgery were included. Anesthesia was induced with a propofol and remifentanil infusion via target-controlled infusion (TCI). Remifentanil infusion was initiated at 3.0 ng/mL, and the response of each patient determined the Ce of remifentanil for the next patient by the Dixon up-and-down method at an interval of 0.5 ng/mL. Rocuronium was administered after propofol and remifentanil reached their preset Ce; 90 seconds later fiberoptic nasotracheal intubation was initiated. Non-invasive blood pressure and heart rate (HR) were measured at pre-induction, the time Ce was reached, immediately before and after intubation, and at 1 and 3 minutes after intubation. The up-and-down criteria comprised a 20% change in mean blood pressure and HR between just prior to intubation and 1 minute after intubation. RESULTS: The median effective effect-site concentration (EC50) of remifentanil was 3.11 ± 0.38 ng/mL by the Dixon's up-and-down method. From the probit analysis, the EC50 of remifentanil was 3.43 ng/mL (95% confidence interval, 2.90-4.06 ng/mL). In PAVA, the EC50 and EC95 of remifentanil were 3.57 ng/mL (95% CI, 2.95-3.89) and 4.35 ng/mL (95% CI, 3.93-4.45). No remifentanil-related complications were observed. CONCLUSIONS: The EC50 of remifentanil for minimizing the cardiovascular changes and side effects associated with fiberoptic nasotracheal intubation was 3.11-3.43 ng/mL during propofol TCI anesthesia with a Ce of 4 ug/mL.
Analgesics, Opioid ; Anesthesia ; Blood Pressure ; Heart Rate ; Hemodynamics ; Humans ; Intubation* ; Intubation, Intratracheal ; Methods ; Propofol

BACKGROUND: The aim of this study was to examine the safety and efficacy of patient-controlled sedation (PCS) according to the lock-out time (LOT, 1 or 2 min) with a demand bolus of propofol and alfentanil fixed during a colonofiberscopy. METHODS: Fifty ASA physical status 1 or 2 patients who underwent a colonofiberscopy were enrolled in this study. They were provided with a PCS pump (Perfusor(R) fm, B Braun Germany, nominal infusion rate, NIR = 1,000 ml/h) containing propofol (9.1 mg/ml) and alfentanil (45.5microgram/ml) in order to self-administer a 2 ml bolus whenever they felt uncomfortable. The lock-out time (LOT) was set to 1 (n = 20, group 1) or 2 (n = 30, group 2) minutes. The Observer's Alertness/Sedation (OAA/S) score, D/A (delivery/attempt, %), blood pressure, heart rate, respiratory rate, SpO2, end tidal CO2 and bispectral index (BIS) were assessed and measured during and/or after the procedures. The verbal descriptive pain scores, as well as the patient's and endoscopist's satisfaction scale were assessed after the procedures. RESULTS: Intraoperative and postoperative pain scores, D/A, the patient's and endoscopist's satisfaction were similar in both groups. However, the lowest BIS values in group 1 was lower than in group 2 (70.3 +/- 12.2 and 77.6 +/- 6.8, respectively, P = 0.010). There were fewer patients whose lowest OAA/S score was <3 in group 2 (4/30) than in group 1 (11/20)(P = 0.002). CONCLUSIONS: With a demand bolus of propofol (18.2 mg) and alfentanil (91.0microgram) fixed, the incidence of over-sedation was higher at LOT 1 min than at LOT 2 min while the efficacy was similar in the PCS with a high NIR during the colonofiberscopy.
Alfentanil* ; Blood Pressure ; Germany ; Heart Rate ; Humans ; Incidence ; Pain, Postoperative ; Propofol* ; Respiratory Rate

INTRODUCTION: Intravenous sedation is performed to ensure smooth and safe surgery. Dental anxiety is a reaction to an unknown danger. The Spielberger's state-trait anxiety inventory (STAI) can be used to simultaneously evaluate the levels of state and trait anxiety. State anxiety is defined as subjective feelings of nervousness. This study assessed the presurgical anxiety using STAI and performed intravenous sedation for patients whose level of state anxiety was > stage IV. Based on our clinical experience, it is believed that higher doses of sedatives are needed to induce the desired levels of sedation in patients with a high level of state anxiety. OBJECTIVES: This study examined whether the sedative consumption of the patient with a high anxiety level increased. PATIENTS AND METHODS: Patients with state anxiety scores of > or =51 were included in Group V, and those with state anxiety scores ranging from 42 to 50 were placed in Group IV. To induce sedation, intravenous access was established, and a bolus dose of 3.0 mg midazolam was administered intravenously. Sedation was maintained by administering a continuous infusion of propofol, which was aimed at achieving an Observer's Assessment of Alertness/Sedation scale of 10-12/20. In this study, midazolam was initially administered when the body movements appeared to occur or the blood pressure increased. This was followed by the administration of higher doses of propofol if low sedation was observed. RESULTS: There were no significant differences in the patient demographics, duration of sedation, and doses of local anaesthetic agents between Groups IV and V. The midazolam dose and mean propofol dose needed to maintain comparable levels of sedation were significantly higher in Group V than in Group IV. CONCLUSION: In female patients, whose level of preoperative state anxiety is more than Stage V of STAI, a large quantity of sedatives is needed for intravenous sedation.
Anxiety ; Blood Pressure ; Demography ; Dental Anxiety ; Dietary Sucrose ; Female ; Humans ; Hypnotics and Sedatives ; Midazolam ; Molar, Third ; Propofol