Effect of ear point embedding on plasma and effect site concentrations of propofol-remifentanil in elderly patients after target-controlled induction / 中国针灸

<p><b>OBJECTIVE</b>To observe the clinical effect of ear point embedding on plasma and effect site concentrations of propofol-remifentanil in elderly patients who underwent abdominal external hernia surgery at the time of consciousness and pain disappearing by target-controlled infusion (TCI) and bispectral index (BIS).</p><p><b>METHODS</b>Fifty patients who underwent elective abdominal hernia surgery were randomly assigned into an observation group and a control group, 25 cases in each one. In the observation group, 30 minutes before anesthesia induction, Fugugou (Extra), Gan (CO), Pizhixia (AT), and Shenmen (TF) were embedded by auricular needles until the end of surgery, 10 times of counter press each point. In the control group, the same amount of auricular tape was applied until the end of surgery at the same points without stimulation 30 minutes before anesthesia induction. Patients in the two groups were given total intravenous anesthesia, and BIS was monitored by BIS anesthesia depth monitor. Propofol was infused by TCI at a beginning concentration of 1.5μg/L and increased by 0.3μg/L every 30s until the patients lost their consciousness. After that, remifentanil was infused by TCI at a beginning concentration of 2.0μg/L and increased by 0.3μg/L every 30s until the patients had no body reaction to pain stimulation (orbital reflex). Indices were recorded, including mean arterial pressure (MAP), heart rate (HR) and the BIS values, at the time of T(entering into the operation room), T(losing consciousness) and T(pain relief), the plasma and effect site concentrations of propofol at T, the plasma and effect site concentrations of remifentanil at T. After surgery we recorded the total amounts of propofol and remifentanil, surgery time and anesthesia time.</p><p><b>RESULTS</b>At Tand T, MAP and HR of the observation group were higher than those of the control group (<0.05,<0.01). At T, the plasma and effect site concentrations of propofol in the observation group were significantly lower than those in the control group (<0.05,<0.01). At T, the plasma and effect site concentrations of remifentanil in the observation group were significantly lower than those in the control group (<0.05,<0.01). There was no significant difference in BIS values at Tand Tbetween the two groups (both>0.05). There was no significant difference in operation time and anesthesia time between the two groups (both>0.05). The total amount of remifentanil in the observation group was significantly lower than that in the control group (<0.01). There was no significant difference in the total amount of propofol between the two groups (>0.05).</p><p><b>CONCLUSIONS</b>Ear points embedding combined with propofol-remifentanil TCI could reduce the plasma and effect site concentrations of propofol and remifentanil and the total amount of remifentanil in elderly patients with extra-abdominal hernia surgery, and had the effect of assisting sedation and analgesia.</p>

Anesthetic management with propofol/remifentanil target controlled infusion for awake craniotomy: A case report

Awake craniotomy is indicated for tumor resection involving eloquent cortex. It allows the operator to perform appropriate cortical mapping during surgery and facilitate maximum tumor resection while minimizing neurologic deficit. Therefore anesthesia should provide adequate analgesia and sedation but also importantly a full consciousness and cooperation for neurologic testing. This case reports the use of target-controlled infusion (TCI) and monitoring of sedation and anesthetic depth through bispectral index (BIS), providing good control of sedation and analgesia to meet frequent changes throughout the different levels of the procedure while maintaining good condition for intraoperative brain mapping. We propose that TCI of propofol and remifentanil in combination may be a useful alternative for awake craniotomy requiring intraoperative brain mapping surgery.

An analysis of correlation between remifentanil effect site concentration and age blunting hemodynamic response to endotracheal intubation

BACKGROUND: There are many studies using propofol-remifentanil target controlled infusion (TCI) for the prevention of adverse hemodynamic changes during tracheal intubation. Most of these studies suggested optimal remifentanil target concentration without considering age. The purpose of this study is to analyze the correlation between concentration of remifentanil and age to blunting adverse hemodynamic responses during tracheal intubation. METHODS: We enrolled ASA physical state I or II 55 patients, aged 12-75 years undergoing elective surgery. Anesthesia was induced using a propofol TCI (Marsh model). A 4micro/ml effect-site concentration of propofol was chosen. Rocuronium 0.6 mg/kg was administered after the patients lost consciousness. Remifentanil TCI (Minto model) was started 1 minute after the propofol injection. Initially, a 3 ng/ml effect-site concentration was chosen. The next concentration was chosen using Dixon's up-and-down method. The non-invasive blood pressure and heart rate were recorded before induction (baseline), after the remifentanil infusion, immediately after intubation as well as 1 and 3 minutes after intubation. RESULTS: Probit analysis revealed a remifentanil effect site EC50 and EC95 in all patients to be 1.768 ng/ml (S.E. +/-0.136) and 2.912 ng/ml (S.E. +/-0.307). Final probit equation was as following consisted with age and remifentanil effect site concentration. Probit = -2.588 + 1.886 remifentanil effect site concentration -0.022 x Age. CONCLUSIONS: The probability of success rate of blunting adverse hemodynamic response is related to the concentration of remifentanil directly and age inversely.

Target-controlled Infusion of Remifentanil during Propofol Induction in Hypertensive Patients: Effects of Three Different Remifentanil Concentrations on Hemodynamic Changes / 대한마취과학회지

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.

Remifentanil Effect-site Concentration Blunting Cardiovascular Responses to Tracheal Intubation for Different Sex during Propofol Infusion / 대한마취과학회지

BACKGROUND: Tracheal intubation induces clinically adverse hemodynamic changes. Various pharmacological strategies for controlling these reponses have been suggested with opioids being widely used. The purpose of this study was to determine the effect site concentration of remifentanil in blunting the cardiovascular responses to tracheal intubation according to gender. METHODS: Eighty ASA physical status I or II patients, aged 20-40 years undergoing elective surgery, were classified into a male group (n = 40) and a female group (n = 40). Anesthesia was induced using a propofol target controlled infusion (TCI: Marsh model). A propofol target effect-site concentration of 4microgram/ml was chosen. Rocuronium 0.6 mg/kg was administered after the patients lost consciousness. Remifentanil TCI (Minto model) was started 1 min after the propofol injection. Initially, an effect-site concentration of 3 ng/ml was chosen. The next concentration was chosen using the up-and-down method reported by Dixon. The non-invasive blood pressure and heart rate were recorded before induction (baseline), after the remifentanil injection, immediately after intubation as well as 1 and, 3 minutes after intubation. RESULTS: Probit analysis revealed a remifentanil effect-site EC50 and EC95 in the male group to be 1.94 ng/ml (95% CI, 1.60-2.27 ng/ml ), 3.07 ng/ml (95% CI, 2.65-4.06 ng/ml), respectively. The EC50 and EC95 in the female group were 1.69 ng/ml (95% CI, 1.35-2.01 ng/ml), 2.81 ng/ml (95% CI, 2.39-3.81 ng/ml), respectively. There were no significant differences between the two groups. CONCLUSIONS: The effect-site concentration of remifentanil blunting the cardiovascular responses to tracheal intubation during propofol TCI anesthesia was between 2 and 3 ng/ml. There were no gender differences.

What is the Optimal Dosage of Remifentanil for Minimizing the Hemodynamic Change to Tracheal Intubation during Induction with Propofol Target-Controlled Infusion? / 대한마취과학회지

BACKGROUND: Laryngoscopy and tracheal intubation are associated with hemodynamic pressor responses, which lead to adverse effect. Opioids have been used to reduce the hemodynamic change. The purpose of this study was to investigate an optimal dosage of remifentanil for attenuating hemodynamic change. METHODS: 120 ASA class 1-2 patients, scheduled for elective surgery, were divided randomly into 4 groups. Anesthesia was induced with vecuronium priming dose (0.01 mg/kg) and TCI of propofol target concentration 8 microgram/ml. This was reduced to 4 microgram/ml when the effect-site concentration had been 3 microgram/ml. After the effect-site concentration had reached 4 microgram/ml, vecuronium (0.09 mg/kg) was given. At the same time, control group received normal saline, group R0.25 received remifentanil 0.25 microgram/kg, group R0.5 received remifentanil 0.5 microgram/kg, group R1 received remifentanil 1 microgram/kg over 60s and an infusion 0.2 microgram/kg/min. Intubation was performed after maximum depression of the single twitch was shown by single twitch stimulation test. Sytolic blood pressure, mean arterial pressure, diastolic blood pressure, heart rate and BIS value were measured preinduction, after propofol induction, immediately before and after intubation and 1, 2, 3, 4 minutes after intubation, respectively. RESULTS: Post-intubation mean arterial pressure decreased significantly from pre-intubation value in group R0.5 and R1 (P < 0.05). In group R0.5 and R1, hypotension and bradycardia occurred but there were no significant differences in their incidence between two groups. CONCLUSIONS: We suggest that remifentanil 0.5 microgram/kg bolus and an infusion of 0.2 microgram/kg/min attenuate the pressor response to tracheal intubation in patients anesthetized with propofol TCI.

Effect of Small-Dose Sufentanil: Target-Controlled Infusion Combined with General Anesthesia Using Propofol / 대한마취과학회지

BACKGROUND: Sufentanil has been shown to act synergistically when combined with propofol, or when combined with potent inhalation anesthetics. The aiml of this study was to determine the dosing rate and target plasma concentration of propofol in the presence of low concentrations and to determine the impact of sufentanil infusion. METHODS: Sixty patients undergoing a plastic surgery and urologic surgery were anesthetized with nitrous oxide, and given a target-controlled infusion (TCI) of sufentanil [target plasma concentrations of 0 (group 1) and 0.05 ng/ml (group 2)], and propofol at rates varying according to the bispectal index (BIS). The mean target concentration (Tc) and infusion rate of propofol according to the changes in the sufentanil concentrations were determined. The recovery time (from stopping the infusion to eye opening) and side effects were compared. RESULTS: The induction time and recovery time were shorter in group 2 than in group 1 (P < 0.05). The infusion rate and mean target concentration of propofol were significantly lower in group 2 (148.8 +/- 25.2 microgram/kg/min, 4.1 +/- 0.8 microgram/ml) than in group 1 (161.7 +/- 26.9 microgram/kg/min, 4.7 +/- 0.5 microgram/ml) (P < 0.01). There were a similar number of side effects in the two groups. CONCLUSIONS: The blood propofol and plasma sufentanil concentrations in the plastic surgery and urologic surgery patients, with respect to satisfactory intraoperative anesthetic conditions and speed of recovery, were 4.1 +/- 0.8 microgram/ml and 0.05 ng/ml.

The Effect-Site Concentration of Remifentanil for Prevention of Increase of Blood Pressure and Heart Rate to Tracheal Intubation during Propofol-Remifentanil Total Intravenous Anesthesia in Korean / 대한마취과학회지

BACKGROUND: Combination of propofol and remifentanil is an ideal regimen for total intravenous anesthesia. The purpose of this study is to determine the effect-site concentration of remifentanil for prevention of hemodynamic responses to tracheal intubation during fixed propofol infusion (4microgram/ml) and to find any sexual differences. METHODS: Thirty ASA physical status I-II patients undergoing general anesthesia were assigned to male (n = 15), and female (n = 15) group. All patients received a target controlled infusion (TCI) of propofol with a fixed effect-site concentration of 4microgram/ml. After target effect-site concentration of propofol and remifentanil was reached, tracheal intubation was performed. The hemodynamic changes (systolic/diastolic blood pressure, mean arterial pressure, and heart rate) were measured at 1 and 2 min before tracheal intubation (baseline), immediately after, 1, 2, 3, 4 and 5 min following tracheal intubation. In both groups, effect-site concentration of remifentanil was initiated with 3 ng/ml. Subsequent concentration of remifentanil was determined by hemodynamic responses of the previous patient to tracheal intubation based on up and down sequential allocation. RESULTS: The mean EC50 of remifentanil for prevention of hemodynamic responses to tracheal intubation were 1.37 ng/ml (95% CI, 0.95-1.81 microgram/ml) in male group and 1.05 microgram/ml (95% CI, 0.68-1.40 ng/ml) in female group, respectively. In addition, there were no statistical significant differences between two groups. CONCLUSIONS: Relatively small dosages of remifentanil (0.68-1.81 microgram/ml) for attenuation of hemodynamic responses to tracheal intubation was needed in Korean population in propofol TCI and there were no sexual differences.

The Effect-Site Concentration of Remifentanil for Prevention of Increase of Blood Pressure and Heart Rate to Tracheal Intubation during Propofol-Remifentanil Total Intravenous Anesthesia in Korean / 대한마취과학회지

BACKGROUND: Combination of propofol and remifentanil is an ideal regimen for total intravenous anesthesia. The purpose of this study is to determine the effect-site concentration of remifentanil for prevention of hemodynamic responses to tracheal intubation during fixed propofol infusion (4microgram/ml) and to find any sexual differences. METHODS: Thirty ASA physical status I-II patients undergoing general anesthesia were assigned to male (n = 15), and female (n = 15) group. All patients received a target controlled infusion (TCI) of propofol with a fixed effect-site concentration of 4microgram/ml. After target effect-site concentration of propofol and remifentanil was reached, tracheal intubation was performed. The hemodynamic changes (systolic/diastolic blood pressure, mean arterial pressure, and heart rate) were measured at 1 and 2 min before tracheal intubation (baseline), immediately after, 1, 2, 3, 4 and 5 min following tracheal intubation. In both groups, effect-site concentration of remifentanil was initiated with 3 ng/ml. Subsequent concentration of remifentanil was determined by hemodynamic responses of the previous patient to tracheal intubation based on up and down sequential allocation. RESULTS: The mean EC50 of remifentanil for prevention of hemodynamic responses to tracheal intubation were 1.37 ng/ml (95% CI, 0.95-1.81 microgram/ml) in male group and 1.05 microgram/ml (95% CI, 0.68-1.40 ng/ml) in female group, respectively. In addition, there were no statistical significant differences between two groups. CONCLUSIONS: Relatively small dosages of remifentanil (0.68-1.81 microgram/ml) for attenuation of hemodynamic responses to tracheal intubation was needed in Korean population in propofol TCI and there were no sexual differences.

What is an Optimal Dosage of Alfentanil for Minimizing the Hemodynamic Change to Endotracheal Intubation during Anesthesia Induction with Propofol Target-Controlled Infusion? / 대한마취과학회지

BACKGROUND: Laryngoscopy and tracheal intubation are associated with hemodynamic pressor responses, which can have adverse effects. During anesthesia induction with propofol target-controlled infusion (TCI), we aimed to determine the most appropriate dosage of alfentanil required for intubation, using a steady effect-site concentration of propofol and with the use of vecuronium. METHODS: Eighty ASA class 1 or 2 patients presenting for elective surgery were allocated at random to one of four groups. Anesthesia was induced in all patients with TCI of propofol target concentration 8 microgram /ml, followed by vecuronium (0.12 mg/kg). This was reduced to 5microgram/ml when the effect-site concentration had been 4microgram/ml. After the effect-site concentrations had reached to 5microgram/ml, control group received normal saline, group 1 received alfentanil 10microgram/kg, group 2 received alfentanil 20microgram/kg, and group 3 received alfentanil 30microgram/kg. Laryngoscopy and intubation were performed 90 s later. Heart rate was monitored continuously. Systolic blood pressure, diastolic blood pressure and mean arterial pressure were measured at pre-induction, post-induction (pre-intubation) and post-intubation, respectively. Complications such as hypotention and bradycardia were recorded until 5 minutes had elapsed after tracheal intubation. RESULTS: Control group showed significant increases associated with tracheal intubation in all hemodynamic variables (P < 0.05). Post-intubation values decreased significantly from pre-induction values in groups 1, 2 and 3 (P < 0.05). In groups 2 and 3, hypotension and bradycardia occurred (zero in group 1) but there were no significant differences in their incidences between the three groups. CONCLUSIONS: We suggest that alfentanil 10microgram/kg constitutes the optimal dosage to obtund the hemodynamic responses to tracheal intubation, using propofol TCI (5microgram/ml) and vecuronium for induction of anesthesia.

Proper Target Concentration of Fentanyl during Endotracheal Intubation with a CACI (Computer Assisted Continuous Infusion) in Patients Undergoing Coronary Artery Bypass Graft Surgery / 대한마취과학회지

BACKGROUND: The computer-assisted continuous infusion (CACI) system was developed to more rapidly attain and to maintain stable effect-site fentanyl concentrations as compared with the intermittent injection method. The CACI system allows the anesthesiologist to control effect-site fentanyl concentrations during various surgical stimuli during cardiac anesthesia. This system can rapidly control the depth of anesthesia and compensate for the disadvantages of IV anesthesia. Early patient recovery also enables early tracheal extubation, which is an important component of the "fast track" cardiac surgery pathway. In this study, the use of a target-controlled infusion of low-dose propofol was combined with the target-controlled infusion of fentanyl for patients undergoing coronary artery bypass graft surgery. The purpose of this study was to evaluate the proper effect-site concentration of fentanyl for the tracheal intubation of patients undergoing coronary artery bypass graft surgery. METHODS: Fifty patients scheduled for elective coronary artery bypass graft surgery were included, and randomly allocated to group L (effect-site fentanyl concentration = 5 ng/ml, n = 25) or group H (effect-site fentanyl concentration = 7.5 ng/ml, n = 25). Anesthesia was induced and maintained by the computer-controlled infusions of propofol and fentanyl. Hemodynamics and other variables were recorded preinduction, and before and 1 minute after intubation. RESULTS: The two groups were compared with regard to demographic and perioperative data. The two groups were similar demographically, and no significant differences was found in any hemodynamic parameter at any time between the two groups. CONCLUSIONS: Both fentanyl regimens provided stable hemodynamics and adequate anesthesia in patients during endotracheal intubation. It is reasonable to say that the lower dose of fentanyl (5 ng/ml) may be the better choice, because it provides the same level of anesthesia during endotracheal intubation during coronary artery bypass graft surgery.

Target-Controlled Infusion of Alfentanil for Conscious Sedation / 대한마취과학회지

BACKGROUND: Opioids are frequently used to relieve pain or to induce sedation during monitored anesthesia care and regional anesthesia. Infusion rates for alfentanil range from 0.25-0.72 microgram/kg/min. This study was performed to define the optimal range of blood concentration of alfentanil to produce a conscious sedation without significant vital sign changes and side effects in spinal anesthesia patients. METHODS: One hundred patients were administered spinal anesthesia with 0.5% hyperbaric bupivacaine 12-18 mg and then a target controlled infusion (TCI) of alfentanil using a syringe pump equiped with a stelpump program. The target concentrations of alfentanil were 20 ng/ml (n = 20, group A20), 25 ng/ml (n = 20, group A25), 30 ng/ml (n = 20, group A30), 35 ng/ml (n = 20, group A35) and 40 ng/ml (n = 20, group A40). Sedation scale, bispectral index (BIS), systolic and diastolic blood pressure, heart rate, SpO2, and anxiety score were checked during the operation and postoperatively one hour later in the recovery room. RESULTS: The sedation scale was significantly higher in groups A30, A35, and A40 than in the other two groups (P < 0.05), but there were no significant difference in BIS among the groups. Mean infusion rates of alfentanil were 0.27-0.46 microgram/kg/min. Time from end of alfentanil infusion to response to a verbal command was significant delayed in groups A30, A35, and A40 than in the other two groups. Recall of operative procedure occurred in 50 65%. Intraoperative hypotension, bradycardia, and respiratory depression occurred more frequently in groups A35, and A40 than in the other three groups (P < 0.05). Incidences of postoperative nausea and vomiting were significantly higher in groups A35, and A40 than in the other three groups (P < 0.05). Heart rate and systolic and diastolic pressures were more significantly lowered during the operation in groups A35, and A40 than in the other three groups (P < 0.05). CONCLUSIONS: Alfentanil has an effective sedation effect at 40% of the analgesic dosage during spinal anesthesia. But, incidences of side effects, like hypotension, bradycardia, and nausea and vomiting increased with alfentanil target concentrations. TCI of alfentanil at 30 ng/ml produces effective sedation, antianxiety effect, and fewer side effects during spinal anesthesia.

Target-Controlled Infusion of Alfentanil and Propofol for Total Abdominal Hysterectomy / 대한마취과학회지

BACKGROUND: Alfentanil has been shown to act synergistically if combined with propofol, with or without nitrous oxide, or if combined with potent inhalation anesthetics. The goal of this study was to determine the dosing rate and target plasma concentration of propofol to supplement nitrous oxide in the presence of varying concentrations of alfentanil and to determine the optimal combination of propofol and alfentanil. METHODS: Sixty patients undergoing a total abdominal hysterectomy (TAH) were anesthetized with nitrous oxide, and given a target-controlled infusion (TCI) of alfentanil [target plasma concentrations of 0 (A0 group), 50 ng/ml (A50 group), and 100 ng/ml (A100 group)], and propofol at rates varied up and down depending on the bispectal index (BIS). The mean target concentration (Tc) and infusion rate of propofol according to changes of concentrations of alfentanil were determined. Recovery time (from infusion stop to eye opening) and side effects were compared. RESULTS: Induction time and recovery time were shortened in the A50 group and A100 group compared with the A0 group (P < 0.05). The infusion rate and mean target concentration of propofol were significantly lower in the A100 group (7.5 mg/kg/h, 3.4ng/ml) than the A0 (12.6 mg/kg/h, 4.5ng/ml) and A50 (10.2 mg/kg/h, 4.0ng/ml) groups (P < 0.01). Side effects did not differ among the three groups. CONCLUSIONS: The optimal blood propofol and plasma alfentanil concentration, with respect to satisfactory intraoperative anesthetic conditions and speed of recovery, are 4.0ng/ml and 50 ng/ml or 3.4ng/ ml and 100 ng/ml in TAH patients.

Optimal Target Concentration of Alfentanil for the Sedation of Urologic Surgical Patients / 대한마취과학회지

BACKGROUND: The purpose of this study was to define the optimal target concentration of alfentanil effective in achieving a sedative, antianxiety and analgesic effect during spinal anesthesia in urologic patients. METHODS: Sixty patients underwent spinal anesthesia with 0.5% hyperbaric bupivacaine 12-18 mg and received a target controlled infusion (TCI) of alfentanil with 0 ng/ml (group A0, n = 15), 20 ng/ml (group A20, n = 15), 30 ng/ml (group A30, n = 15) or 40 ng/ml (group A40, n = 15). Sedation scale, bispectral index (BIS), anxiety level and infusion rate of alfentanil were checked during the operation. RESULTS: Sedation scale was significantly higher in group A30 (3.3) and A40 (3.8) than group A0 (1.9) and A20 (2.5)(P<0.05). Incidences of intraoperative hypotension, respiratory depression, postoperative nausea and vomiting, and dizziness were significantly higher in group A40 than the other groups (P<0.05). There were no significant differences in BIS, anxiety level and incidences of recall of the operative procedure among the groups (P<0.05). CONCLUSIONS: TCI of alfentanil with 30 ng/ml produces effective sedation and antianxiety effect without significant side effects during spinal anesthesia.

The Optimal Target Propofol and Alfentanil Concentrations during Plastic Surgery / 대한마취과학회지

BACKGROUND: Propofol and alfentanil are frequently combined to provide total intravenous anesthesia (TIVA). The goals of this study were to determine the target plasma concentration (predicted plasma concentration) of propofol required to provide satisfactory anesthesia in the presence of nitrous oxide over a range of alfentanil infusions for analgesia and to determine the dosing rates required to achieve adequate anesthesia. METHODS: Sixty patients undergoing plastic surgery were anesthetized with 50% nitrous oxide, alfentanil (0 [A0 group] or 5ng/kg loading followed by 0.12ng/kg/min [A5 group] or 10ng/kg loading followed by 0.25ng/kg/min [A10 group] or 20ng/kg loading followed by 0.5ng/kg/min [A20 group]) and propofol using a target-controlled infusion (TCI). The mean target concentration and infusion rate of propofol, and induction and recovery time according to changes of the alfentanil regimen were checked. RESULTS: Induction and recovery time were prolonged in the A0 group more than other groups, and recovery time was shortened in the A10 group more than the other three groups (P < 0.05). The infusion rate and mean target concentration of propofol had significant impact among the groups (P < 0.05). Side effects did not differ among the groups. CONCLUSIONS: The optimal target plasma propofol concentrations and infusion rates of alfentanil, both with satisfactory intraoperative anesthetic conditions and speed of recovery, are 3.51, 3.02, 2.35ng/ml and 0.12, 0.25, 0.5ng/kg/min with 5, 10, 20ng/kg loading in plastic surgery patients. We recommand 0.25ng/kg infusion with 10ng/kg loading of alfentanil combined with 3.02ng/ml of target plasma concentration of propofol as the best combination dosage to shorten recovery time.

Effect of electromyogram variation on BIS accuracy during general anesthesia / 解放军医学杂志

40), the values of BIS, electromyogram (EMG), signal quality index (SQI), mean arterial pressure(MAP), and heart rate(HR) were recorded every minute for 5min, then additional vecuronium (0.05mg/kg) was administered, and the values of the parameters above mentioned were registered for the next 10min. Results BIS value decreased significantly 3 min after the administration of the additional vecuronium (P0.05). Conclusion A misleading BIS value may be caused by the decline of muscle relaxant during the maintenance stage of propofol/fentanyl anesthesia, which greatly influence the accuracy of BIS monitoring.