BACKGROUND: This study undertook to compare the effect-site concentration of remifentanil for prevention of hemodynamic responses to endotracheal intubation, employing the single-lumen tracheal tube and the double-lumen bronchial tube during total intravenous anesthesia. METHODS: Based on the nature of the surgery, 38 patients undergoing general anesthesia were assigned either to the single-lumen tube group or the double-lumen tube group. Anesthesia was induced by a target controlled infusion of propofol, with an effect-site concentration of 4 µg/ml. Remifentanil was then administered to the first patient in each group, with an effect-site concentration of 3.5 ng/ml. Subsequent concentration of remifentanil was determined by hemodynamic responses of the previous patient to intubation, based on the up-and-down method. RESULTS: The effect-site concentrations of remifentanil for prevention of hemodynamic responses to endotracheal intubation in 50% of patients (EC₅₀) were 2.8 ng/ml (95% CI, 2.0–3.7 ng/ml) in the single-lumen tube group, and 2.9 ng/ml (95% CI, 2.5–3.2 ng/ml) in the double-lumen tube group. No significant difference was observed between the two groups. CONCLUSIONS: The effect-site concentration of remifentanil for prevention of hemodynamic responses to endotracheal intubation did not differ during total intravenous anesthesia, using either the single-lumen tracheal tube or the double-lumen bronchial tube.
Anesthesia ; Anesthesia, Endotracheal ; Anesthesia, General ; Anesthesia, Intravenous ; Hemodynamics* ; Humans ; Intubation* ; Intubation, Intratracheal ; Methods ; Propofol

OBJECTIVE: To evaluate the effects of intravenous anesthesia in painless esophagoscopy for extraction of foreign bodies in the esophagus. METHOD: Forty-two patients underwent painless esophagoscopy, and extracted the foreign bodies in the esophagus. RESULT: Thirty-two cases had their foreign bodies extracted smoothly and no serious complication occurred,the other 10 cases were mucosal injuries of esophagus with no obvious foreign body. CONCLUSION Intravenous sedation with propofol in extraction of foreign bodies in the esophagus can relieve the suffering and adverse reactions, and it is safe, quick, comfortable and effective for extraction of foreign bodies in the esophagus and is worthy to be applied in the clinic.
Anesthesia, Intravenous ; methods ; Anesthetics, Intravenous ; Esophagoscopy ; methods ; Esophagus ; injuries ; Female ; Foreign Bodies ; therapy ; Humans ; Male ; Propofol

Adult ; Anesthesia, General ; methods ; Anesthesia, Intravenous ; methods ; Cesarean Section ; methods ; Female ; Humans ; Muscular Atrophy, Spinal ; Pregnancy

This paper present a microcontroller system for target controlled infusion according to pharmacodynamic parameters of intravenous anesthetics. It can control the depth of anesthesia by adjusting the level of plasma concentrations. The system has the advantages of high precision, extended function and easy operation. It has been now used in the clinical anesthesia.
Algorithms ; Anesthesia, Intravenous ; instrumentation ; methods ; Anesthetics, Intravenous ; administration & dosage ; pharmacokinetics ; Computer Systems ; Humans ; Infusions, Intravenous ; Microcomputers ; Software Design

Preoyerative sedation of children is a difficult problem of great importance, for the psychic trauma comsequent to anticipation of surgery may be as great a hazard to the patient as his original disease. Until now, a number of sedatives have been used commonly for adequate sedation of pediatric patients, but, no method has been universally accepted. At our hospital fifty pediatric patients receiving general anesthesia for minor elective surgery were studied to evaluate the effect of ketamine hydrochloride as a preanesthetic agent. The results were as follows: 1) The onset of drag action was about, about 5min. 2) The induction of anesthesia and maintenances of operation was smooth, because a sedative effect was obtained without cardiovascular and respiratory depression. 3) With a small dosage of ketamine(2mg/kg), patients were free from apprehension. So, perioperative psychic trauma was preventible. 4) The two excitable patients were anesthetized by intravenous anesthetics with ease. 5) Mild complications, accurred but they were not significant.
Anesthesia ; Anesthesia, General ; Anesthetics, Intravenous ; Child* ; Humans ; Hypnotics and Sedatives ; Ketamine* ; Methods ; Respiratory Insufficiency

Due to individual differences of the depth of anaesthesia (DOA) controlled objects, the drawbacks of monitoring index, the traditional PID controller of anesthesia depth could not meet the demands of nonlinear control. However, the adjustments of the rules of DOA fuzzy control often rely on personal experience and, therefore, it could not achieve the satisfactory control effects. The present research established a fuzzy closed-loop control system which takes the cerebral state index (CSI) value as a feedback controlled variable, and it also adopts the particle swarm optimization (PSO) to optimize the fuzzy control rule and membership functions between the change of CSI and propofol infusion rate. The system sets the CSI targets at 40 and 30 through the system simulation, and it also adds some Gaussian noise to imitate clinical disturbance. Experimental results indicated that this system could reach the set CSI point accurately, rapidly and stably, with no obvious perturbation in the presence of noise. The fuzzy controller based on CSI which has been optimized by PSO has better stability and robustness in the DOA closed loop control system.
Anesthesia ; methods ; Anesthesiology ; methods ; Anesthetics, Intravenous ; administration & dosage ; Feedback ; Fuzzy Logic ; Propofol ; administration & dosage

BACKGROUNDAwareness is a serious complication of general anesthesia. In China, the incidence of intraoperative awareness was 1% in patients undergoing total intravenous anesthesia (TIVA). In this study, we compared the incidence of awareness between Bispectral index (BIS)-guided and routine TIVA protocol and evaluated the effect of BIS on preventing awareness.

METHODSA prospective, randomized, double-blinded, multicenter controlled trial was performed. Patients (≥ 18 years of age) undergoing TIVA were randomly divided into BIS-guided group (Group A, BIS was monitored and recommended to maintain between 40 - 60) and control group (Group B, BIS was monitored but the screen was covered). The intraoperative BIS values were downloaded and the BIS trends of confirmed awareness cases were analyzed to determine whether light anesthesia existed.

RESULTSOf the total 5228 patients, 2919 patients were assigned to Group A and 2309 to Group B. Four cases of confirmed awareness (0.14%) were reported in the BIS-guided group and 15 (0.65%) in the control group (P = 0.002, OR = 0.21, 95% confidence intervals: 0.07 - 0.63). The incidence of possible awareness (0.14% vs. 0.26%, P = 0.485) and dreaming (3.1% vs. 3.1%, P = 0.986) was comparable between BIS-guided group and the control group. Among the 19 confirmed awareness cases, intraoperative BIS trends of six cases were downloaded and identified. Five of them showed signs of light anesthesia as BIS > 60 and lasted 19 - 106 minutes, whereas one case had a stable BIS trend and the values were within 60 during the operation. Another five awareness cases were reviewed for anesthesia procedures, of which improper light anesthesia were confirmed.

CONCLUSIONSBIS-guided TIVA (BIS was recommended to maintain between 40 - 60) decreased the risk of awareness compared with routine TIVA. The main reason for awareness was light anesthesia.

Adolescent ; Adult ; Aged ; Anesthesia, General ; methods ; Anesthesia, Intravenous ; methods ; Female ; Humans ; Intraoperative Awareness ; prevention & control ; Male ; Middle Aged ; Young Adult

This paper presents a microcontroller system for target controlled infusion according to pharmacodynamic parameters of intravenous anesthetics. It can control the depth of anesthesia by adjusting the level of plasma concentrations. The system has the advantages of high precision, extending power and easy manipulation. It has been used in the clinical anesthesia.
Anesthesia, Intravenous ; instrumentation ; methods ; Anesthetics, Intravenous ; administration & dosage ; pharmacokinetics ; Drug Delivery Systems ; methods ; Drug Therapy, Computer-Assisted ; methods ; Humans ; Monitoring, Intraoperative ; methods

Recently, intravenous sedatives and analgesics are being commonly used in children because of the clinical need for increasing the non-operating room anesthesia and intraoperative neurophysiologic monitoring during surgery and environmental problems. Administration methods (single bolus, intermittent bolus, or continuous infusion) vary according to the clinical request. Continuous intravenous anesthesia based on the weight is still the most commonly used method for administration of intravenous drugs in children. With the newly developed statistical method and medical devices, target controlled infusion of intravenous anesthetics has become possible in pediatric anesthesia, in spite of the difficulty in obtaining the specific pharmacokinetic model using pharmacokinetic parameters. Nowadays, a pharmacokinetic-pharmacodynamic model for complete effect-site target controlled infusion is available for use in children. Several drugs are used for pediatric sedation, such as analgesics or anesthetics such as opioids (remifentanil, sufentanil or alfentanil), neuromuscular blocking agents or sedatives (midazolam, dexmedetomidine). All these drugs have been used in continuous infusion via various methods including target controlled infusion. Many studies have been carried out by researchers to use target controlled infusion for safe and efficient treatment in children according to the increase in clinical demand. Various pharmacokinetic-pharmacodynamic models for commonly used intravenous drugs will be reviewed, with a focus on children in this small discussion.
Analgesics ; Analgesics, Opioid ; Anesthesia ; Anesthesia, Intravenous ; Anesthetics ; Anesthetics, Intravenous ; Child* ; Humans ; Hypnotics and Sedatives ; Intraoperative Neurophysiological Monitoring ; Methods ; Neuromuscular Blocking Agents ; Sufentanil

Recently, intravenous sedatives and analgesics are being commonly used in children because of the clinical need for increasing the non-operating room anesthesia and intraoperative neurophysiologic monitoring during surgery and environmental problems. Administration methods (single bolus, intermittent bolus, or continuous infusion) vary according to the clinical request. Continuous intravenous anesthesia based on the weight is still the most commonly used method for administration of intravenous drugs in children. With the newly developed statistical method and medical devices, target controlled infusion of intravenous anesthetics has become possible in pediatric anesthesia, in spite of the difficulty in obtaining the specific pharmacokinetic model using pharmacokinetic parameters. Nowadays, a pharmacokinetic-pharmacodynamic model for complete effect-site target controlled infusion is available for use in children. Several drugs are used for pediatric sedation, such as analgesics or anesthetics such as opioids (remifentanil, sufentanil or alfentanil), neuromuscular blocking agents or sedatives (midazolam, dexmedetomidine). All these drugs have been used in continuous infusion via various methods including target controlled infusion. Many studies have been carried out by researchers to use target controlled infusion for safe and efficient treatment in children according to the increase in clinical demand. Various pharmacokinetic-pharmacodynamic models for commonly used intravenous drugs will be reviewed, with a focus on children in this small discussion.
Analgesics ; Analgesics, Opioid ; Anesthesia ; Anesthesia, Intravenous ; Anesthetics ; Anesthetics, Intravenous ; Child* ; Humans ; Hypnotics and Sedatives ; Intraoperative Neurophysiological Monitoring ; Methods ; Neuromuscular Blocking Agents ; Sufentanil