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ABSTRACT: The aim of the present study was to determine the effect of low-dose remifentanil on the monitoring quality of the Bispectral index for mechanically ventilated patients. Twelve patients who underwent elective surgery and required mechanical ventilation post-operatively were enrolled in this study with written informed consent. Eligible patients were divided into two groups. Patients in the remifentanil group received low-dose remifentanil (0.05-0.125 μg/kg/min) and propofol (1-3 mg/kg/h). Patients in the control group received propofol (1-3 mg/kg/h). Levels of sedation were evaluated by both the Richmond Agitation Sedation Scale (RASS) and BIS monitor (A2000-XP, version 4.0, Aspect Medical Systems, Newton, USA). Monitoring quality was assessed by a correlation between RASS and BIS values. These values were assessed by single regression analysis and a P value of <0.05 was considered significant. There was a significant correlation between RASS and BIS values (P = 3 × 10(-12), R (2) = 0.67) in the remifentanil group, but not in the control group (P = 0.50, R (2) = 0.057). The administration of low-dose remifentanil makes BIS a more precise tool for sedated patients under mechanical ventilation in the ICU.
International Journal of Clinical Monitoring and Computing 07/2012;
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ABSTRACT: An 86-year-old woman with low cardiac function was scheduled to undergo hip fracture surgery. Preoperative electrocardiogram showed complete left bundle brunch block, first degree atrioventricular block, left axis deviation and bigeminy. However, her electrocardiogram had changed to complete atrioventricular block on arrival at operating theater. ACC/AHA guideline on perioperative cardiovascular evaluation and care for non cardiac surgery indicates the assessment of both the urgency of the surgery and cardiac complications. Because complete atrioventricular block is classified to "active cardiac conditions", we decided to postpone the surgery for more detailed evaluation and treatment of cardiac conditions. In spite of the discontinuation of digoxin and carvegilol, complete atrioventricular block continued for a week, and the permanent pacemaker was inserted. The surgery was performed 2 weeks following the insertion of the pacemaker without any problems under combined general and lumbar epidural anesthesia.
Masui. The Japanese journal of anesthesiology 06/2011; 60(6):706-9.
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ABSTRACT: We report a man with severe dilated cardiomyopathy with an implantable cardioverter-defibrillator (ICD) who underwent sigmoidectomy. During the operation, the defibrillation function of the ICD has been stopped to prevent malfunction caused by electrocautery artifacts, and the electrodes of the external defibrillator were placed on the chest wall. Pulmonary artery catheter was inserted under X-ray imaging to prevent the interference between ICD leads and the catheter. Anesthesia was maintained with combined general and thoracic epidural anesthesia. In order to prevent the afterload increase, both milrinone and carperitide were administered. Fluid resuscitation was also performed to maintain circulating blood volume. As a result of the management, patient has not exhibited any heart failure.
Masui. The Japanese journal of anesthesiology 09/2010; 59(9):1194-7.
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ABSTRACT: A 60-year-old female with multiple sclerosis (MS) and supranuclear palsy (PSP) was scheduled for right eye iridotomy, left eye phaco emulcification aspiration and insertion of the intraocular lens. Her medical conditions included prolonged immobility, spastic contracture, and a history of convulsion. She was administered with L-dopa, tizanidine, bacrofen, and dantrorane. Anesthesia was induced with propofol 50 mg and fentanyl 25 microg intravenously, and inhalation of oxygen and 1% sevoflurane. Tracheal intubation was performed without neuromuscular blocking agents. Anesthesia was maintained with inhalation of oxygen-air (Fi(O2) 0.4) and 1-1.5% sevoflurane, combined with regional anesthesia. Supplemental fentanyl was administered as needed. The bispectral index (BIS) was monitored and kept between 40 and 60. The operation proceeded uneventfully. After discontinuation of anesthetic agents, she awoke immediately and the BIS index returned to the pre-induction level. Neither neurological disturbances nor unexpected event were observed postoperatively. In patients with MS, it is important to remember the possibility of drugs moving into the central nervou system easily due to the disturbance of the blood-brai barrier. Patients with PSP are usually medicated wit. various medicines which have possibility of interactin with anesthetics. Therefore, we used least anesthetic as possible. In this case, monitoring of BIS seemed to be useful to maintain the minimum sevoflurane concen trations needed.
Masui. The Japanese journal of anesthesiology 07/2010; 59(7):906-10.
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ABSTRACT: We present a life-threatening case of hemothorax resulting from right brachiocephalic vein perforation during right internal jugular vein catheterization. We considered that the guidewire had punctured the right brachiocephalic vein extraluminally and the catheter inserted over the guidewire had enlarged the size of the perforation. Despite the use of proper technique, an angle-tip guidewire may perforate the venous wall. Therefore, when there is negative aspiration after central venous catheterization, it is important to perform an emergency chest radiograph before proceeding with surgery; it is also important not to use an angle-tip guidewire.
Journal of Anesthesia 02/2009; 23(1):135-8. · 0.83 Impact Factor
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ABSTRACT: It has been reported some patients have opened eyes with low bispectral index (BIS) values immediately following electroconvulsive therapy (ECT). We investigated the time course of the recovery from amnesia and BIS values.
Five patients with depression requiring repeated ECT procedures were enrolled. The patients were asked to recall an object presented prior to anesthesia at four specific points (prior to induction, upon regaining consciousness following ECT, when they returned to their ward, and when their BIS values had returned to pre-anesthetic levels). BIS data were recorded continuously until BIS values returned to the pre-anesthetic levels at their ward. The area under a receiver-operating characteristic (ROC) curve was used to detect associations between the BIS values and disturbance of memory function.
A total of 41 ECT stimuli were administered. After returning to their ward, patients generally fell asleep, with BIS values of between 50 and 70, and they woke up 1-2 h later. All the patients could recall the presented object prior to anesthesia and when the BIS values had returned to pre-anesthetic levels. The area under the ROC curve for the detection of memory disturbance was 0.902.
The present study demonstrated a high frequency of patients falling asleep and the frequent occurrence of prolonged periods of low BIS values following ECT. The results of memory testing showed that ECT procedures resulted in amnesia. The ROC curve findings suggest a strong association of memory disturbance with BIS values. In conclusion, patients generally fell asleep, with low BIS values, for 1-2 h after ECT, and a prolonged period of impairment of memory formation was associated with low BIS values.
Journal of Anesthesia 02/2009; 23(2):182-7. · 0.83 Impact Factor
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ABSTRACT: A case of accidental total spinal anesthesia was presented. A 47-year-old woman was scheduled for a total abdominal hysterectomy. An epidural catheter was inserted at the L1-2 interspace and 10 ml of 1% ropivacaine was injected. Following surgery, the patient did not regain consciousness and we confirmed total spinal anesthesia because of the cerebrospinal fluid leak through the epidural catheter. Therefore propofol was administered again until the recovery of sufficient spontaneous breathing confirmed approximately 3 hours following administration of ropivacaine, and patient was extubated. No neurologic deficits could be detected.
Masui. The Japanese journal of anesthesiology 03/2007; 56(2):173-4.
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ABSTRACT: The prediction of the hypnotic states is useful to maintain the adequate anesthesia. During propofol anesthesia, the respiratory depression has been documented in a dose-dependent manner. Therefore, we investigated whether the respiratory depression under the spontaneous breathing reflected the estimated effect site propofol concentrations (Cp) in a dose-dependent fashion.
We enrolled 12 patients for elective lower limb surgery under combined subarachnoid anesthesia and propofol sedation. The respiratory parameters and BIS were measured at the Cp of 5 microg x ml(-1) followed by the 0.5 microg x ml(-1) decrements until the patients' movement. Effective indices to predict patients' movement were determined by receiver-operator characteristics.
The significant correlations within a particular patient between the respiratory parameters and Cp were observed, although those were not between the patients. An EtCO2 of 53 mmHg or greater represents a clinically determinant condition for non-movement of the patients.
We concluded that the respiratory parameters during spontaneous breathing were useful indices to predict the changes in the effect site propofol concentrations and to maintain the adequate anesthetic levels.
Masui. The Japanese journal of anesthesiology 11/2004; 53(10):1130-5.
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ABSTRACT: The effect of nitrous oxide either as a sole agent or with volatile anesthetic agents on the central nervous system has been well studied. However, it has not been clarified during various levels of propofol anesthesia. We therefore evaluated the effect of nitrous oxide on the central nervous system using bispectral index (BIS) and suppression ratio (SR) under various levels of propofol anesthesia.
Twelve patients were enrolled for the study. After the administration of subarachnoid block, propofol was infused using a stepped down series (effect site concentration of 5, 4, 3 microg x ml(-1)) for 20 minutes. After obtaining BIS and SR at each concentration, nitrous oxide was added.
When 67% of nitrous oxide was added to the estimated effect site propofol concentration of 5 microg x ml(-1), BIS decreased and SR increased indicating that the nitrous oxide had a depressant effect on the central nervous system. On the other hand, nitrous oxide combined with 3 or 4 microg x ml(-1) of propofol did not cause significant changes in BIS and SR, suggesting that nitrous oxide did not have a suppressive effect.
We conclude that nitrous oxide has different effects on BIS according to their basal propofol concentrations.
Masui. The Japanese journal of anesthesiology 07/2004; 53(6):650-3.
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Toshiya Koitabashi
Journal of Anesthesia 02/2004; 18(2):141-3. · 0.83 Impact Factor
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ABSTRACT: Marshall-Smith syndrome (MSS) is a rare clinical disorder, characterized by accelerated skeletal maturation, facial anomalies, failure to thrive and death in early infancy due to respiratory complications. We experienced the difficult airway case with MSS. A 4-year-old boy underwent tenosynovectomy for the snapping finger. Although his upper airway was diagnosed as almost normal on the fiber-optic laryngoscope examination, he frequently showed pharyngeal collapse during sleep. Anesthesia was induced and maintained with N2O-O2-sevoflurane using oral-airway without muscle relaxants. But, when we inserted the laryngoscope in order to clarify the existence of the difficult intubation, we could only see a part of the epiglottis. We concluded that we must treat MSS as difficult airway and intubation, even if in the mild case of MSS.
Masui. The Japanese journal of anesthesiology 09/2003; 52(8):860-2.
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ABSTRACT: The effect of opioid administration on the bispectral index (BIS) during general anesthesia is controversial. Several investigators have reported BIS to be insensitive to opioid addition, whereas others have found a hypnotic response. We designed this study to examine the effect of remifentanil on BIS during combined regional/general propofol anesthesia under steady-state conditions. After Human Investigations Committee approval, 19 healthy ASA physical status I or II patients were enrolled in a prospective experimental design. Regional anesthesia was initiated and general anesthesia induced by using computer-assisted continuous infusion of propofol. Propofol was incrementally adjusted to a BIS of approximately 60. After 20 min at a stable propofol infusion rate, a remifentanil computer-assisted continuous infusion (effect-site target concentration of 0.5, 2.5, and then 10 ng/mL) was sequentially administered at stepped 15-min intervals. BIS decreased from 56 +/- 2 to 44 +/- 1, 95% spectral edge frequency from 17.9 +/- 0.5 Hz to 15.0 +/- 0.4 Hz, heart rate from 84 +/- 5 bpm to 62 +/- 4 bpm, and mean arterial blood pressure from 93 +/- 4 mm Hg to 69 +/- 3 mm Hg with increasing remifentanil concentration. A significant linear correlation between BIS, 95% spectral edge frequency, heart rate, and log (remifentanil effect-site) concentration was found. The change in baseline BIS was relatively modest but significant, suggesting that remifentanil has some sedative/hypnotic properties, or that it potentiates the hypnotic effect of propofol. IMPLICATIONS: This experiment identified a significant, dose-dependent decrease in bispectral index (BIS), 95% spectral edge frequency, heart rate, and mean arterial blood pressure with increasing remifentanil dose. The change in baseline BIS was relatively modest but significant, suggesting that remifentanil has some sedative/hypnotic properties, or that it potentiates the hypnotic effect of propofol.
Anesthesia & Analgesia 07/2002; 94(6):1530-3, table of contents. · 3.29 Impact Factor
