Toshiya Koitabashi

Remifentanil dose/electroencephalogram bispectral response during combined propofol/regional anesthesia.

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.

Life-threatening hemothorax resulting from right brachiocephalic vein perforation during right internal jugular vein catheterization

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.

Integration of suppression ratio in the bispectral index

After gaining approval by the Human Investigations Committee (Ichikawa General Hospital, Tokyo Dental College, Chiba, Japan) and obtaining informed written consent, the author enrolled 40 patients (30 men and 10 women) who underwent elective surgery under general anesthesia monitored using the BIS. Patients were excluded if any of the following conditions were met: seizure disorder; or longterm opioid, sedative, or alcohol use. Premedication consisted of 0.5mg·kg 1 of atropine, with or without midazolam 1–3mg, intramuscularly 30min prior to the anesthetic induction. After arrival in the operating room, patients were connected to standard physiological monitors. EEG (At1-Fpzt or At2Fpzt) was measured using a self-preparing sensor (BIS Sensor) and BIS monitor (A-1050; BIS version 3.4; Aspect Medical Systems, Newton, MA, USA). The BIS and SR were recorded continuously by a computer. Anesthesia was maintained with either propofol or sevoflurane, with or without regional anesthesia. The selection of the agents and their concentrations were at the discretion of the attending anesthesiologists. After the surgery, the author evaluated the relationship between the BIS and the SR from the obtained data. Statistical analysis was performed using the Pearson correlation coefficient to evaluate linear regression. The patients’ average age was 42 14 years. The average weight and height were 65 16 kg and 160 11cm, respectively. After IV induction, all patients were endotracheally intubated with vecuronium and ventilated mechanically. End-expiratory CO2 was maintained between 30 and 35mmHg. The BIS decreased in an anesthetic dose-dependent fashion in all patients and reached a plateau of 30 (Fig. 1). In all patients with BIS in the 30s, the SR value was between 0 and 40%. In seven of the 40 patients, the SR exceeded 40%. In these situations, the author observed an inverse proportional relationship between the BIS and the SR. For an SR greater than 40%, the BIS was completely determined from the SR component. The

Intravenous midazolam passage into breast milk

It is desirable to allow breast-feeding as soon as possible after anesthesia. It is common for anesthesiologists to encounter nursing mothers who invariably question whether breast feeding after anesthesia can harm their infants [1]. Only limited reviews concerned with diffusion into breast milk could be found, and in particular there were no studies on breast-feeding after intravenous administration of midazolam to the mother. The present study reports the degree to which intravenously administered midazolam passed from plasma to breast milk in one patient.

Low bispectral index values following electroconvulsive therapy associated with memory impairment

PurposeIt 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.MethodsFive 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.ResultsA 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.ConclusionThe 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.

Palliative Care for Oral Cancer

Palliative care is an approach that improves the quality of life of patients and their families facing the problems associated with life-threatening illness. For pain assessment, it is important to obtain not only the onset, duration, location, quality, pattern, character, and intensity of pain but also aggravating and relieving factors, associated symptoms and signs, and current pain management agents and their effectiveness. To treat cancer pain, this principles can be summarized in five steps (by the mouth, by the clock, by the ladder, for the individual, and attention to detail). The use of opioids should not be affected by unfounded fears such as respiratory depression, tolerance, or dependence. When satisfactory alleviation of cancer pain cannot be achieved as a result of regular assessment of the response to analgesics or therapy, opioid-resistant cancer pain should be assessed. Opioid-resistant cancer pain includes underdosing, poor absorption or intake of opioids, raised intracranial pressure, and neuropathic pain. In cases of neuropathic pain, adjuvant analgesics such as anticonvulsants or antidepressants should be considered. Both prevention and appropriate interventions for opioid-related adverse effects such as constipation, nausea and vomiting, and drowsiness are one of the key components to continue to treat cancer pain.