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

BACKGROUND: We evaluated the changes in effect-site concentration (Ce) of propofol, hemodynamic responses and heart rate variability (HRV) in elderly patients with or without hypertension according to bispectral index (BIS) during target effect-site controlled infusion (TCEI) of propofol. METHODS: Twenty four elderly patients with (group H, n = 12) or without hypertension (group C, n = 12) were recruited. We analyzed the spectral components of HRV at the BIS of 60-80 and 40-60 during TCEI of propofol. We also measured systolic and diastolic blood pressure (SBP and DBP), mean arterial pressure (MAP), heart rate (HR) and predicted Ce of propofol. RESULTS: The predicted Ce in group H (2.76 +/- 0.20microg/ml) was significantly lower than that in group C (3.53 +/- 0.24microg/ml) at the BIS of 60-80. BP in both groups decreased significantly in a BIS-dependent manner. The low frequency power (LnLF) in group H decreased significantly to 83.5 +/- 4.6% and 79.1 +/- 4.4% of pre-induction value at the BIS of 60-80 and 40-60, respectively. At the BIS of 60-80, the change of HR in group H was inversely proportional to the change of total (LnTP) and high frequency power (LnHF) significantly (P < 0.05). CONCLUSIONS: The group H required significantly lower Ce of propofol than group C for BIS 60-80. The LnLF in group H decreased significantly at the BIS of 60-80 and 40-60 compared with pre-induction value. At the BIS value of 60-80, the change of HR in group H showed inversely proportional correlation with that of LnTP and LnHF significantly.
Aged* ; Arterial Pressure ; Blood Pressure ; Heart Rate* ; Heart* ; Hemodynamics* ; Humans ; Hypertension ; Propofol*

BACKGROUND: Laryngeal mask airway (LMA) can be inserted without muscle relaxant in patients who have received propofol. Remifentanil that is recently used opioid effectively attenuates the hemodynamic responses to laryngoscopy. This study was to investigate the effects of remifentanil on the quality and hemodynamic response of LMA insertion after intravenous propofol induction without muscle relaxant. METHODS: Forty patients (ASA I or II, 20-65 years) were randomly allocated to control and remifentanil group. Control group received propofol 4microg/ml alone, remifentanil group received propofol 4microg/ml and remifetanil 2 ng/ml by target controlled infusion. LMA insertion condition was assessed by Muzi's score (jaw mobility, coughing, movement). The time interval to loss of eyelash reflex, to BIS < 60 and to insertion of LMA were recorded. The BIS and hemodynamic changes were measured at preinduction (baseline), preinsertion and postinsertion. RESULTS: Loss of consciousness and LMA insertion were more rapid with remifentanil group than control group (P < 0.05). Clinically acceptable insertion of LMA were observed in 35% and 70% of patients in the control and remifentanil group, respectively. There were significant elevations in heart rate, mean blood pressure after insertion of LMA in control group, but no elevations in remifentanil group. And there were no significant differences in BIS in both groups. CONCLUSIONS: The LMA insertion with propofol-remifentanil can provide more favorable condition and stable hemodynamic status compared with propofol alone.
Blood Pressure ; Cough ; Heart Rate ; Hemodynamics ; Humans ; Laryngeal Masks ; Laryngoscopy ; Propofol* ; Reflex ; Unconsciousness

BACKGROUND: This study compared the hemodynamic effects of target-controlled infusion (TCI) of remifentanil (4, 5, or 6 ng/ml) during propofol induction in normotensive and hypertensive patients. It was also examined whether increasing the remifentanil concentrations might reduce propofol consumption at the loss of consciousness (LOC). METHODS: Seventy five ASA 1 or 2 normotensive (N) and 75 ASA 2 hypertensive (H) patients were randomly allocated according to the remifentanil target effect-site concentration of 4, 5, 6 ng/ml (groups N4, N5, N6, H4, H5, H6 respectively). After the start of remifentanil TCI, when the target effect-site concentration of remifentanil had been reached, the TCI of propofol (4microgram/ml) was started. The effect-site concentration of propofol at LOC was recorded. When the target effect-site concentration of propofol was reached, 0.6 mg/kg of rocuronium was administered. Tracheal intubation was carried out after 2 minutes. The noninvasive blood pressure, heart rate (HR), bispectral index (BIS) and infused dose of remifentanil and propofol were recorded. RESULTS: Groups H5, H6 and N6 resulted in significant decrease in blood pressure after intubation. In groups N4 and H4, clinically significant increases in HR (above 25% of the baseline) were observed at 1 minute after intubation. The effect-site concentration of propofol at LOC was significantly lower in groups N6 and H6 compared to groups N4 and H4. CONCLUSIONS: In hypertensive patients, a dosing requirement of lower effect-site concentration of 4 ng/ml remifentanil might be adequate during propofol induction. Increasing the remifentanil concentrations from 4 to 6 ng/ml may reduce the propofol requirements for hypnosis.
Blood Pressure ; Heart Rate ; Hemodynamics* ; Humans ; Hypertension ; Hypnosis ; Intubation ; Propofol* ; Unconsciousness

BACKGROUND: Various maneuvers are commonly used to achieve the ideal operative field necessary for successful endoscopic sinus surgery (ESS). There are a few contradictory reports on this subject and the consensus is that propofol anesthesia results in a better or similar surgical field and less or similar amount of bleeding than volatile anesthesia. The aim of this study was to compare the surgical field in patients in whom intravenous anesthesia is used as opposed to balanced general anesthesia. METHODS: Sixty patients undergoing ESS were randomly assigned into three groups, each of which used a different type of anesthesia: propofol/remifentanil (PRO/REM) group, sevoflurane/remifentanil (SEV/REM) group, and desflurane/remifentanil (DES/REM) group. We aimed to maintain the intraoperative mean blood pressure (MBP) at 65 mmHg and the heartrate (HR) at about 75 beats per minute. The quality of visibility of the surgical field was graded, using a validated scoring system, 60 minutes after the start of the operation. RESULTS: All groups had a similar MBP and mean HR at 60 minutes after the operation started. There was no significant differences among the three groups for surgical grade score (P = 0.83). CONCLUSIONS: In this comparative study of three anesthetic combinations (PRO/REM, SEV/REM, and DES/REM) in patients undergoing ESS with controlled BP and HR, we did not observe any significant differences in the surgical grade scores.
Anesthesia ; Anesthesia, Intravenous ; Blood Pressure ; Consensus ; Hemorrhage ; Humans ; Isoflurane ; Methyl Ethers ; Piperidines ; Propofol ; Sinusitis