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>

Effect of various anaesthesia depth on the sublingual microcirculation / 天津医药

Objective To investigate the effects of different depth of anesthesia on sublingual microcirculation. Meth?ods ASA gradeⅠ-Ⅱpatients (n=20) were scheduled for elective thyroid surgery and included in the prospective observa?tional study. Midazolam 0.05 mg·kg, sufentanil 0.3μg·kg-1 and rocuronium 0.6 mg·kg-1 were administrated intravenously to induce anesthesia which was then maintained by continuous intravenous infusion of propofol. Target medication concentra?tion increased 0.5 mg·L-1, regulated based on BIS. The patients underwent endotracheal intubation and mechanical ventila?tion. Sublingual microcirculations were evaluated by sidestream dark field (SDF) imaging at T1 (BIS baseline ), T2 (50 0.05). Conclusion When BIS value sit between 40 and 50, it can best inhibit stress response and attenuate the agitation of microcirculation.

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.

Cross-clamping of the descending thoracic aorta leads to the asymmetrical distribution of propofol during cardiopulmonary bypass surgery / 대한마취과학회지

BACKGROUND: We hypothesized that cross-clamping of the descending thoracic aorta (CcDTA) would result in significant changes in plasma propofol concentrations (Cp) proximal and distal to the cross-clamp. We investigated the effect of CcDTA on Cp centrally and distally, including the pulmonary artery and the cardiopulmonary bypass (CPB) cannula. METHODS: The bispectral index (BIS) was recorded during CcDTA in eight patients undergoing thoracic aortic surgery using target-controlled total intravenous anesthesia with propofol. The calculated Cp was maintained at 3 microg/ml. Cp was measured in blood samples drawn from the right radial artery, left dorsalis pedis artery, pulmonary artery, and the long venous CPB cannula. RESULTS: Complete data were obtained from six patients. BIS decreased significantly in all cases 5 minutes after initiating CcDTA. BIS continued to decrease in association with increasing propofol concentrations. During CcDTA, Cp in samples from the radial and pulmonary arteries (3.5 +/- 0.50 and 2.9 +/- 0.63 microg/ml, mean +/- SD) was significantly higher than in samples from the dorsalis pedis artery and the venous cannula (1.1 +/- 0.22 and 1.4 +/- 0.02 microg/ml) (P < 0.05). CONCLUSIONS: The results suggest that almost all of the blood returning from the superior vena cava during CcDTA directly enters the pulmonary circulation without mixing with blood from the inferior vena cava. Observed changes in anesthetic blood concentrations could be due to the presence of a split circulation and asymmetrical distribution of propofol induced by CcDTA and CPB.

Comparative Study of Brain Protection Effect between Thiopental and Etomidate Using Bispectral Index during Temporary Arterial Occlusion

OBJECTIVE: This study was conducted to compare the effect of etomidate with that of thiopental on brain protection during temporary vessel occlusion, which was measured by burst suppression rate (BSR) with the Bispectral Index (BIS) monitor. METHODS: Temporary parent artery occlusion was performed in forty one patients during cerebral aneurysm surgery. They were randomly assigned to one of two groups. General anesthesia was induced and maintained with 1.5-2.5 vol% sevoflurane and 50% N2O. The pharmacological burst suppression (BS) was induced by a bolus injection of thiopental (5 mg/kg, group T) or etomidate (0.3 mg/kg, group E) according to randomization prior to surgery. After administration of drugs, the hemodynamic variables, the onset time of BS, the numerical values of BIS and BSR were recorded at every minutes. RESULTS: There were no significant differences of the demographics, the BIS numbers and the hemodynamic variables prior to injection of drugs. The durations of burst suppression in group E (11.1+/-6.8 min) were not statistically different from that of group T (11.1+/-5.6 min) and nearly same pattern of burst suppression were shown in both groups. More phenylephrine was required to maintain normal blood pressure in the group T. CONCLUSION: Thiopental and etomidate have same duration and a similar magnitude of burst suppression with conventional doses during temporary arterial occlusion. These findings suggest that additional administration of either drug is needed to ensure the BS when the temporary occlusion time exceed more than 11 minutes. Etomidate can be a safer substitute for thiopental in aneurysm surgery.

The effect of remifentanil on sedation during midazolam induced sedation under brachial plexus block / 대한마취과학회지

BACKGROUND: The effects of remifentanl on bispectral index (BIS) and sedation are controversial. The aim of this study was to evaluate the effects of continuous remifentanil infusion (0.03microgram/min/kg) on sedation by using BIS and the modified Observer's Assessment of the Alertness/Sedation Scale (OAA/S) during midazolam induced sedation after achieving pain free state by brachial plexus block. METHODS: In this study 40 ASA physical status 1 or 2 adult patients scheduled to undergo upper extremity surgery under brachial plexus anaesthesia were included. After obtaining adequate brachial plexus block, patients were randomly allocated to two groups. All patents received a single dose of midazolam 2 mg intravenously and continuous infusion (2 mg/h). At 15 minutes after midazolam injection, Group C received saline infusion and Group R received additional remifentanil (0.4microgram/kg bolus plus continuous infusion (0.03microgram/kg/min)). The mean arterial blood pressure (MAP), heart rate (HR), SpO2, respiration rate (RR), and BIS were recorded every 5 min after injection of midazolam. The patient's level of sedation was assessed using the modified OAA/S and BIS immediately after MAP, HR, SpO2, and RR measurements. RESULTS: There are no significant differences in MAP, HR, BIS, and the modified OAA/S between two groups but RR was significant reduced in Group R compared with Group C after remifentanil infusion. CONCLUSIONS: The remifentanil showed no effect on BIS and the modified OAA/S during midazolam induced sedation under pain free state.

Adequate Dosage for Midazolam Premedication in Koreans / 대한마취과학회지

BACKGROUND: Midazolam is often used as an anxiolytic premedication before surgery. Although the sedative, anxiolytic, and amnestic properties of midazolam may be desirable before the induction of general anesthesia, respiratory function is impaired frequently by larger doses of midazolam. Therefore, we evaluated the adequate doses of midazolam premedication on anxiolytic and sedation without its serious side effects. METHODS: Eighty ASA I or II adult patients scheduled for elective minor surgery were randomly allocated to four groups according to premedication doses of midazolam. They were group 1: midazolam 0.05 mg/kg IM for lean body mass (LBM); group 2: midazolam 0.075 mg/kg IM for LBM; group 3: midazolam 0.1 mg/kg IM for LBM.; group 4: midazolam 0.125 mg/kg IM for LBM. Blood pressure, heart rate, bispectral index (BIS), oxygen saturation (SpO2), anxiety visual analogue scale (VAS), and observer's assessment of alertness and sedation (OAA/S) scores were measured before and at 30 minutes after midazolam premedication. The frequency of apnea, defined as a cessation of spontaneous respiration for more than 10 seconds, was recorded. Induction time and dose requirements in propofol-induced general anesthesia were recorded at the loss of opening their eyes on verbal command and eyelid reflex after starting the propofol infusion. Following intubation, blood pressure and heart rate were measured. RESULTS: The bispectral index and anxiety VAS was significantly decreaced in group 3 and group 4. However, oxygen saturation were significantly lower in group 4 compared with group 3. CONCLUSIONS: We concluded that group 3 (midazolam 0.1 mg/kg IM for LBM) is the proper premedication dosage for anxiolytic and sedation in Koreans without respiratory side effects.

Awareness Detection during a Cesarean Section under General Anesthesia Using Bispectral Index Monitoring / 대한마취과학회지

BACKGROUND: A light plane of general anesthesia is chosen for fetal safety during a cesarean section. Therefore an experience of wakefulness and pain perception is not infrequent and can be distressful to patients. The electroencephalogram-derived bispectral index (BIS) is a promising new method to assess anesthetic adequacy. This study was designed to assess the adequacy of general anesthesia and to evaluate the usefulness of the BIS in monitoring the awareness during a cesarean section. METHODS: Twenty one parturients undergoing general anesthesia for an elective caesarean section were examined. Anesthesia was induced with 4 mg/kg thiopental and 1 mg/kg succinylcholine, and then followed with a mixture of 50% N2O, 50% O2 and 0.8% enflurane at a flow of 4 L/min. Before administration of succinylcholine, a tourniquet was applied to the free arm and inflated to 250 mmHg. Responsiveness to verbal commands using the Tunstall isolated forearm technique was detected and the BIS was monitored throughout the study period. RESULTS: The incidence of responsiveness to verbal commands were 33% at the time of skin incision and fetal delivery respectively. BIS values of response to commands were significantly higher than that of no respose at both time points (p < 0.05). Fisher's exact test suggested that the BIS value less than 75 was related to unresponsiveness to verbal commands at time of skin incision (p < 0.05) and the BIS less than 85 at fetal delivery (p < 0.05). CONCLSIONS: These results suggest that adequate anesthesia is not provided with a mixture of 50% N2O, 50% O2 and 0.8% enflurane at a flow of 4 L/min at the time of skin incision and fetal delivery. In addition BIS could be a predictor of awareness during cesarean section under general anesthesia.

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.