OBJECTIVETo observe the safety and feasibility of tracheal intubation by target-controlled infusion of propofol and remifentanil without muscle relaxant in children.

METHODSTotally 100 4-10-year-old pediatric patients (ASA1) who had been scheduled for plastic surgery were equally divided into remifentanil group and control group through computer-generated randomized grouping. In all patients, five minutes after intravenous administration of atropine 0.01 mg/kg and midazolam 0.1 mg/kg, propofol was infused at the targeted effect-site concentration (Ce of 6 μg/ml. When the intended target Ce of propofol was reached, the remifentanil group began to be infused with remifentanil at a Ce of 5 ng/ml, and normal saline (0.1 ml/kg) was injected simultaneously. In the control group remifentanil was replaced by normal saline and rocuronium (0.8 mg/kg) was injected together with the normal saline. After the equilibration of plasma and the Ce of remifentanil were reached, tracheal intubation was attempted. The complications during the induction and tracheal intubation were recorded. The intubating conditions were assessed using a five-point scoring system based on ease of laryngoscopy, vocal cords position, coughing, jaw relaxation and limb movement.

RESULTSThe success rate of tracheal intubation was in 90% in remifentanil group and 98% in the control group (P=0.122).CONCLUSION Target-controlled infusion of propofol and remifentanil at Ce of 6 μg/ml and 5 ng/ml is feasible for the induction and tracheal intubation without muscle relaxant in children.

Child ; Child, Preschool ; Female ; Humans ; Infusions, Intravenous ; Intubation, Intratracheal ; Male ; Piperidines ; administration & dosage ; Propofol ; administration & dosage

OBJECTIVETo observe the effects of remifentanil combined with naloxone on human sperm motility in vitro and to investigate its possible mechanism.

METHODSTwenty normal semen samples were collected, each divided into 13 aliquots, one as the control and the others treated in vitro with different concentrations of remifentanil or remifentanil + naloxone for 35 min. The percentage of progressive mobile sperm was assessed by computer-assisted sperm analysis at 5, 10, 15, 20 and 35 min.

RESULTSCompared with the control group, remifentanil at 0.1, 1, 10 and 100 microg/L significantly decreased sperm motility at 5 and 10 min in a dose-dependent manner, with no significant difference at 15 and 30 min; sperm motility showed no significant difference on 5 -35 min exposure to naloxone at 0.004 -0.04 mg/L, nor on 5, 10, 15 and 20 min exposure at 0.4 -4 mg/L, but was significantly increased at 35 min. Compared with the corresponding concentrations of remifentanil alone, remifentanil + naloxone remarkably increased sperm motility at 0.1 + 0.004, 1 + 0.04, 10 + 0.4, and 100 + 4 mg/L at 5 and 10 min, with no obvious difference at 15 and 30 min.

CONCLUSIONThe onset and offset of the effect of remifentanil on sperm motility are rapid and its inhibitory effect can be antagonized by naloxone, which may be related with the micro-opioid receptor.

Adult ; Humans ; Male ; Naloxone ; administration & dosage ; pharmacology ; Piperidines ; administration & dosage ; pharmacology ; Sperm Motility ; drug effects ; Spermatozoa ; drug effects ; Young Adult

Adolescent ; Adult ; Anesthesia ; Child ; Evoked Potentials, Auditory ; Humans ; Midazolam ; pharmacology ; Monitoring, Intraoperative ; Piperidines ; administration & dosage ; Propofol ; administration & dosage ; Spine ; surgery

OBJECTIVETo evaluate target-controlled infusion (TCI) of remifentail-propofol and the balanced anesthesia of fentanyl-isoflurane during the operation with suspension laryngscope.

METHODSSixty ASA I-II patients scheduled for the surgery through suspension laryngoscopy were randomly divided into two groups: TCI group and control group. In TCI group, anesthesia was maintained with TCI remifentanil-propofol which was stopped at the end of operation. The target plasma concentration of remifentanil was set at 6 microg/L and propofol at 3 mg/L. In control group, anesthesia was induced with intravenous fentanl 2.5 microg/kg and propofol 1-2 mg/kg, maintained with fentanl 0.03 microg.kg(-1). min(-1) and 1% isoflurane which was stopped at the end of surgery. Intubation was facilitated with succinylcholine 1-1.5 mg/kg.MAP, HR, ECG, S(p)O(2) and P(ET)CO(2) were monitored during anesthesia. The following parameters were recorded and compared between two groups: (1) the changes in blood pressure (BP), heart rate(HR) and S(p)O(2) at different time point; (2) recovery profile including the time of response to verbal commands, autonomous breathing, tracheal extubation, orientation recovery, discharging from PACU after operation; (3) OAAS scores after operation; (4) postoperative complications; (5) unexpected events and awareness during operation.

RESULT(1) The hemodynamics were stable while the target plasma concentration of remifentanil was set at 6 microg/L and propofol at 3 mg/L. (2) During tracheal intubation, suspension laryngoscope was inserted, and extubation MAP was significantly lower in TCI group than that in control group; (3) There were no significant differences in hemodynamic values and S(p)O(2) of different time points between two groups. Study group was faster than control group on recovery profile including the time of response to verbal commands, autonomous breathing, tracheal extubation, orientation recovery and discharging from PACU. There was respectively one unexpected event in both groups.

CONCLUSIONRemifentanil supplemented with isoflurane anesthesia can achieve the optimal hemodynamic stability during the operation with suspension laryngoscopy and better recovery profile from anesthesia than fentanyl.

Adolescent ; Adult ; Anesthetics, Combined ; administration & dosage ; Anesthetics, Intravenous ; administration & dosage ; Blood Pressure ; Female ; Heart Rate ; Humans ; Laryngoscopy ; methods ; Male ; Middle Aged ; Piperidines ; administration & dosage ; Propofol ; administration & dosage

OBJECTIVETo observe the clinical effectiveness of inductions and tracheal intubating conditions with 3% sevoflurane and different doses of remifentanil without muscle relaxant in children.

METHODSTotally 120 peadiatric patients (aged 4-10 years, American Society of Anesthesiologists grade I for inhalational induction) were randomly allocated into group I (remifentanil 1 microg/kg), group II (remifentanil 2 microg/kg), group III (remifentanil 3 microg/kg), and control group (vecuronium bromide 0.1 mg/kg). After inhalational induction with 3% sevoflurane and 60% nitrous oxide in 40% oxygen for 2 minutes, remifentanil 1 microg/kg, 2 microg/ kg, and 3 microg/kg were intravenously injected over 1 minute into patients in group I , group II, and group III, respectively. After remifentanil administration and manual ventilation for 1 minute, the trachea was intubated. In the control group, 2 minutes after intravenous administration of vecuronium bromide 0.1 mg/kg, tracheal intubation was attempted. Agitation, intubating satisfactoriness, and the circulation changes after tracheal intubation and anesthesia induction were observed.

RESULTSIn these four groups, agitation occurred in 37.5% of patients during sevoflurane induction. Satisfactory intubation rate was 70.0% in group I, 86.7% in group II, 90.0% in group III, and 93.3% in the control group. Compared with the control group, the impact of tracheal intubation on the circulatory system was smaller in group I , II , and III.

CONCLUSIONSInduction with 3% sevoflurane combined with remifentanil can be smoothly performed, followed by the successful tracheal intubation. The intubating conditions are more satisfactory with 3% sevoflurane combined with remifentanil 2 microg/kg or 3 microg/kg.

Anesthesia, Inhalation ; Anesthetics, Inhalation ; administration & dosage ; Child ; Child, Preschool ; Dose-Response Relationship, Drug ; Female ; Humans ; Intubation, Intratracheal ; adverse effects ; Male ; Methyl Ethers ; administration & dosage ; Piperidines ; administration & dosage

OBJECTIVETo observe the impacts of doxapram on anesthetic efficacy and respiratory and circulatory functions during anesthesia with remifentanil given by target-controlled infusion (TCI) combined with propofol in painless artificial abortion.

METHODSA total of 120 ASA I women requiring voluntarily painless artificial abortion were randomized into two equal groups. One group was given remifentanil by TCI at 2 ng/ml and propofol 1mg/kg (group I), and the other given remifentanil by TCI, propofol, and doxapram 0.6 mg/kg (group II). The anesthetic efficacy and respiratory and circulatory suppression during anesthesia were observed.

RESULTSBoth of the two groups showed satisfactory anesthetic efficacy with comparable the BIS values (P>0.05). No significant difference was noted in the induction time and awaking time between the two groups (P>0.05), but group I had more serious respiratory and circulatory depression than group II (P<0.05).

CONCLUSIONDoxapram may attenuate respiratory and circulatory depression during anesthesia with remifentanil given by TCI combined with propofol in painless artificial abortion, and provide comparable anesthetic efficacy.

Abortion, Induced ; Adolescent ; Adult ; Anesthetics, Combined ; Doxapram ; administration & dosage ; Female ; Humans ; Infusions, Intravenous ; Middle Aged ; Piperidines ; administration & dosage ; Propofol ; administration & dosage ; Treatment Outcome

BACKGROUNDLittle is known about the influence of liver transplantation on the pharmacokinetics of most anesthetic drugs. The goal of this study was to study the population pharmacokinetics of remifentanil in the different phases of orthotopic liver transplantation (OLT) and the influence of relevant factors.

METHODSThirteen adult patients undergoing OLT were enrolled. A single bolus infusion of remifentanil 5 microg/kg was administered during the preanhepatic, anhepatic and neohepatic phases of OLT. Arterial blood samples of 1.5 ml were collected at 0 (baseline), 1, 2, 3, 5, 7, 10, 15, 20, 25, 30, 45, 60 and 90 minutes after drug administration. Remifentanil concentration was assayed by high-performance liquid chromatography/mass spectrometry/mass spectrometry (HPLC/MS/MS). Population pharmacokinetic modeling was performed using nonlinear mixed-effects modeling (NONMEM).

RESULTSThe pharmacokinetics of remifentanil in patients undergoing OLT was best described by a two-compartment open model. The pharmacokinetic parameters were not influenced by age, gender, operative phase, blood temperature, rehydration volume, or blood loss volume during sampling. The volume of distribution in the central compartment (V(1)) and the volume of distribution in the peripheral compartment (V(2)) were influenced by body weight.

CONCLUSIONSThe population pharmacokinetics of remifentanil in patients undergoing OLT can be well described by a two-compartment open model. The functional status of the liver does not significantly affect the pharmacokinetics of remifentanil, but the body weight is an influential factor of V(1) and V(2).

Adult ; Chromatography, High Pressure Liquid ; Female ; Humans ; Liver Transplantation ; Male ; Middle Aged ; Piperidines ; administration & dosage ; pharmacokinetics ; Tandem Mass Spectrometry

OBJECTIVETo explore the preventive effect of etomidate-induced myoclonus by different concentrations of target-controlled infusion of remifentanil.

METHODSA total of 120 cases undergoing general anesthesia were randomly divided into 4 groups according to different concentrations of target controlled infusion of remifentanil using plasma target controlled infusion ( Minto model) , in which the target concentration was set as 1 f.Lg/L ( group A) , 2 f.Lg/L ( group B) , 3 f.Lg/L ( group C) , and 4 f.Lg/L ( group D) . Five minutes after the balance of effect compartment, induction with etomidate 0. 3 mglkg was conducted intravenously. The intensity and duration of myoclonus was recorded.

RESULTSThe incidence of etomidate-induced myoclonus was 70.9%, 33.3%, 26.7%, and 0 in groups A, B, C, and D, respectively. Along with the increase of the remifentanil concentration, the incidence of severe myoclonus gradually reduced, which was significantly lower in group B and C than in group A ( P < 0. 05). When the concentration reached 4 f.Lg/L, bradycardia and apnea appeared.

CONCLUSIONMyoclonus induced by etomidate under general anesthesia can be prevented by target controlled infusion of remifentanil, with 2-3 f.Lg/L being the optimal concentration.

Adult ; Anesthetics, Intravenous ; administration & dosage ; adverse effects ; Etomidate ; adverse effects ; Female ; Humans ; Male ; Middle Aged ; Myoclonus ; chemically induced ; prevention & control ; Piperidines ; administration & dosage

BACKGROUNDAwake intubation requires an anesthetic management that provides sufficient patient safety and comfort, adequate intubating conditions, and stable hemodynamics. In this prospective clinical study, our aim was to determine the median effective dose (ED(50)) of remifentanil in combination with midazolam and airway topical anesthesia for awake laryngoscopy and intubation.

METHODSThirty-six female adult patients, scheduled for elective plastic surgery under general anesthesia requiring orotracheal intubation were included in this study. Ten minutes after intravenous administration of midazolam 0.1 mg/kg, patients were assigned to receive remifentanil in bolus, followed by a continuous infusion. The bolus dose and infusion rate of remifentanil were adjusted by a modified Dixon's up-and-down method. Patient's reaction score at laryngoscopy and an Observer's Assessment of Alertness/Sedation Scale (OAA/S) were used to determine whether the remifentanil dosage regimen was accepted. During laryngoscopy, 2% lidocaine was sprayed into the airway to provide the topical anesthesia. ED(50) of remifentanil was calculated by the modified Dixon up-and-down method, and the probit analysis was then used to confirm the results obtained from the modified Dixon's up-and-down method. In the patients who were scored as "accept", patient's OAA/S and reaction scores at different observed points, intubating condition score and patient's tolerance to the endotracheal tube after intubation were evaluated and recorded. Blood pressure and heart rate at different measuring points were also noted.

RESULTSED(50) of remifentanil for awake laryngoscopy and intubation obtained by the modified Dixon's up-and-down method was (0.62 +/- 0.02) microg/kg. Using probit analysis, ED(50) and ED(95) of remifentanil were 0.63 microg/kg (95% CI, 0.54 - 0.70) and 0.83 microg/kg (95% CI, 0.73 - 2.59), respectively. Nineteen patients who were scored as "accept" had an OAA/S of > 15 and tolerated well laryngoscopy without significant discomfort or gagging. The mean intubating condition score was 1.8 +/- 0.8. The endotracheal tube was well tolerated. During awake laryngoscopy and intubation, blood pressure and heart rate were also kept stable. The postoperative follow up showed that no patient recalled discomfort and pain for airway manipulation.

CONCLUSIONSWhen combined with midazolam 0.1 mg/kg and airway topical anesthesia, ED(50) of remifentanil for successful awake laryngoscopy and intubation is 0.62 microg/kg in bolus followed by continuous infusion of 0.062 microg*kg(-1)*min(-1). This sedation and analgesia regimen can provide patient safety and comfort, ensure adequate intubating conditions, maintain hemodynamic stability, and prevent negative recall of the airway procedure.

Adolescent ; Adult ; Analgesics, Opioid ; administration & dosage ; Dose-Response Relationship, Drug ; Female ; Follow-Up Studies ; Humans ; Intubation, Intratracheal ; methods ; Laryngoscopy ; methods ; Piperidines ; administration & dosage ; adverse effects ; Prospective Studies ; Wakefulness

OBJECTIVETo assess the value of compound anesthesia of transcutaneous electrical point stimulation and Remifentanil and the efficacy of this method on postoperative acute pain.

METHODSSixty cases with vertebral lamina internal fixation decompression operation were selected and randomly divided into 2 groups, an observation group and a control group, 30 cases in each group. The patients in the observation group received compound anesthesia of transcutaneous electrical point stimulation at Hegu (LI 4), Laogong (PC 8), Neiguan (PC 6) and Waiguan (TE 5) 30 min before anesthesia induction with HANS stimulator and then Remifentanil anesthesia. During the operation, the stimulation was lasted for 30 min and ceased for 30 min until the end of operation. The patients in the control group received simple Remifentanil anesthesia. The dosage of the narcotic, changes of both blood pressure and heart rate during operation, before and after extubation and the pain degree, etc. were investigated in the two groups.

RESULTS(1) The dosage of Isoflurane, (0.52 +/- 0.33)vol%, in the observation group was significantly lower than (1.12 +/- 0.18) vol% in the control group (P < 0.01). (2) Both blood pressure and heart rate during operation, before and after extubation in the observation group were lower than those before operation (P < 0.01), and both the blood pressure and heart rate during operation in the control group were lower than those before operation (P < 0.01). The blood pressure after extubation in the observation group was significantly lower than that of the control group (P < 0.01), and the heart rate before and after extubation in the observation group was significantly lower than that of the control group (P < 0.01). (3) The time of extubation and palinesthesia in the observation group were significantly shorter than those in the control group (P < 0.01). (4) In the observation group, the VAS scores after palinesthesia in 26 cases were < 4, and in 4 cases were > or = 5, while in the control group, the scores in 4 cases were < 4 and in 20 cases > or = 5, with a significant difference between the two groups (P < 0.01).

CONCLUSIONCompound anesthesia of transcutaneous electrical point stimulation and Remifentanil can reduce the dosage of narcotics, shorten the time of palinesthesia and effectively prevent and treat acute pain after Remifentanil anesthesia.

Acupuncture Analgesia ; Adult ; Anesthesia Recovery Period ; Anesthetics, Intravenous ; administration & dosage ; Electroacupuncture ; Female ; Humans ; Male ; Middle Aged ; Pain, Postoperative ; prevention & control ; therapy ; Piperidines ; administration & dosage ; Spine ; surgery