Tomo Hayase

The usefulness of an earphone-type infrared tympanic thermometer for intraoperative core temperature monitoring.

BACKGROUND:In this study we sought to determine the usefulness of a novel earphone-type infrared tympanic thermometer (IRT) for core temperature monitoring during surgery. METHODS:Two groups of patients were studied under different surgical conditions. The first group consisted of 18 adult patients (ASA I or II) who had been scheduled for elective surgery under general anesthesia. Before induction of general anesthesia, an earphone-type IRT was inserted into either the left or right ear canal. Tympanic temperature was monitored and recorded along with both rectal and esophageal temperatures during anesthesia. The second group consisted of eight adult patients (ASA II or III) who had been scheduled for cardiac surgery with cardiopulmonary bypass. Similar to the first group, tympanic temperature was measured by the earphone-type IRT and recorded along with the rectal and esophageal temperatures during cooling and rewarming phases of cardiopulmonary bypass. RESULTS:Study 1—The average temperature (±2 sd) measured with the IRT was +0.08°C (±0.34°C) above the esophageal temperature, and that with the rectal temperature was +0.11°C (±0.55°C) above the esophageal temperature. Study 2—The average temperature (±2 sd) measured with the IRT was +0.72°C (±2.2°C) above the esophageal temperature during cooling and warming phases during cardiac surgery with cardiopulmonary bypass. CONCLUSIONS:The earphone-type IRT might be used in a clinical setting for reliable and continuous core temperature monitoring during an operation.

Efficacy and Safety of a Lidocaine and Ropivacaine Mixture for Scalp Nerve Block and Local Infiltration Anesthesia in Patients Undergoing Awake Craniotomy.

Background: Mixtures of various local anesthetics, such as lidocaine and ropivacaine, have been widely used. However, their efficacy and safety for scalp nerve blocks and local infiltration during awake craniotomy have not been fully elucidated. Methods: We prospectively investigated 53 patients who underwent awake craniotomy. Scalp block was performed for the blockade of the supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater occipital, and lesser occipital nerves with a mixture containing equal volumes of 2% lidocaine and 0.75% ropivacaine, including 5 &mgr;g/mL of epinephrine. Infiltration anesthesia was applied at the site of skin incision using the same mixture. The study outcomes included changes in heart rate and blood pressure after head pinning and skin incision, and incidence of severe pain on emergence from anesthesia. Total doses and plasma concentrations of lidocaine and ropivacaine were measured at different time points after performing the block. Results: The heart rate and blood pressure after head pinning were marginally, but significantly, increased when compared with baseline values. There were no significant differences in heart rate and blood pressure before and after the skin incision. Nineteen percent of the patients (10/53) complained of incisional pain at emergence from anesthesia. The highest observed blood concentrations of lidocaine and ropivacaine were 1.9±0.9 and 1.1±0.4 &mgr;g/mL, respectively. No acute anesthetic toxicity symptom was observed. Conclusions: Scalp block with a mixture of lidocaine and ropivacaine seems to provide effective and safe anesthetic management in patients undergoing awake craniotomy.

Effect of sevoflurane anesthesia on the comprehensive mRNA expression profile of the mouse hippocampus

Postoperative nausea and vomiting (PONV) is a common complication after general anesthesia. Recent studies suggested that the hippocampus is involved in PONV. Hypothesising that hippocampal dopaminergic neurons are related to PONV, we examined the comprehensive mRNA profile of the hippocampus, using a sevoflurane-treated mouse model to confirm this. This study was conducted after approval from our institutional animal ethics committee, the Animal Research Center of Sapporo Medical University School of Medicine (project number: 12-033). Eight mice were assigned to two groups: a naοve group and a sevoflurane group (Sev group). In the Sev group, four mice were anesthetised with 3.5% sevoflurane for 1 hour. Subsequently, mRNA was isolated from their hippocampal cells and RNA sequencing was performed on an Illumina HiSeq 2500 platform. Mapping of the quality-controlled, filtered paired-end reads to mouse genomes and quantification of the expression levels of each gene were performed using R software. The Rtn4rl2 gene that encodes the Nogo receptor was the most up-regulated gene in the present study. The expression levels of dopamine receptor genes and the tachykinin gene were increased by sevoflurane exposure, while the genes related to serotonin receptors were not altered by sevoflurane exposure. The expression levels of LIM-homeodomain-related genes were highly down-regulated by sevoflurane. These findings suggest that sevoflurane exposure induces dopaminergic stimulation of hippocampal neurons and triggers PONV, while neuronal inflammation caused by LIM-homeodomain-related genes is down-regulated by sevoflurane.

The influence of depth of anesthesia on motor evoked potential response during awake craniotomy.

OBJECTIVE Motor evoked potentials (MEPs) are a critical indicator for monitoring motor function during neurological surgery. In this study, the influence of depth of anesthesia on MEP response was assessed. METHODS Twenty-eight patients with brain tumors who underwent awake craniotomy were included in this study. From a state of deep anesthesia until the awake state, MEP amplitude and latency were measured using 5-train electrical bipolar stimulations on the same site of the precentral gyrus each minute during the surgery. The depth of anesthesia was evaluated using the bispectral index (BIS). BIS levels were classified into 7 stages: < 40, and from 40 to 100 in groups of 10 each. MEP amplitude and latency of each stage were compared. The deviation of the MEP measurements, which was defined as a fluctuation from the average in every BIS stage, was also considered. RESULTS A total of 865 MEP waves in 28 cases were evaluated in this study. MEP amplitude was increased and latency was decreased in accordance with the increases in BIS level. The average MEP amplitudes in the > 90 BIS level was approximately 10 times higher than those in the < 40 BIS level. Furthermore, the average MEP latencies in the > 90 BIS level were 1.5-3.1 msec shorter than those in the < 60 BIS level. The deviation of measured MEP amplitudes in the > 90 BIS level was significantly stabilized in comparison with that in the < 60 BIS level. CONCLUSIONS MEP amplitude and latency were closely correlated with depth of anesthesia. In addition, the deviation in MEP amplitude was also correlated with depth of anesthesia, which was smaller during awake surgery (high BIS level) than during deep anesthesia. Therefore, MEP measurement would be more reliable in the awake state than under deep anesthesia.

work stress in medical anaesthesiology trainees

Pract Res Clin Anaesthesiol 2006; 20: 81–99. 3. Kin N, Konstadt SN, Sato K, Hanaoka K. Reduction of bispectral index value associated with clinically significant cerebral air embolism. J Cardiothorac Vasc Anesth 2004; 18: 82–84. 4. Hemmerling TM, Olivier JF, Basile F, Le N, Prieto I. Bispectral index as an indicator of cerebral hypoperfusion during off-pump coronary artery bypass grafting. Anesth Analg 2005; 100: 354–356. 5. Szekely B, Saint-Marc T, Degremont AC, Castelain MH, Fischler M. Value of bispectral index monitoring during cardiopulmonary resuscitation. Br J Anaesth 2002; 88: 443–444. 6. Gilbert TT, Wagner MR, Halukurike V, Paz HL, Garland A. Use of bispectral electroencephalogram monitoring to assess neurologic status in unsedated, critically ill patients. Crit Care Med 2001; 29: 1996–2000. 7. Deogaonkar A, Gupta R, DeGeorgia M et al. Bispectral Index monitoring correlates with sedation scales in braininjured patients. Crit Care Med 2004; 32: 2403–2406.

TACR1 gene polymorphism and sex differences in postoperative nausea and vomiting

We hypothesised that the genetic effect of single nucleotide polymorphisms in the TACR1 gene, which encodes NK1 receptors, could influence the sex difference in postoperative nausea and vomiting. Thirty‐two selected single nucleotide polymorphisms were genotyped by the Sanger sequencing method in 200 patients who underwent lower abdominal surgery. The incidence and severity of postoperative nausea and vomiting were evaluated after surgery. The rs3755468‐SNP showed significant association with the incidence and severity of postoperative nausea and vomiting (p = 0.016). The TT haplotype defined by two single nucleotide polymorphisms, including the rs3755468‐SNP, was associated with reduced incidence and severity of postoperative nausea and vomiting in female patients (p = 0.03). The rs3755468‐SNP is located within the predicted oestrogen response element and a DNase I hypersensitive site. The single nucleotide polymorphisms in the TACR1 gene are associated with sex differences in postoperative nausea and vomiting and may help to elucidate the mechanisms underlying these differences.

clinical performance of a novel portable epoc™ Analyzer for Arterial Blood Gas and electrolyte Testing in Operating Rooms

Background: A new blood gas analyzer (epoc™, Epocal Inc.) has recently been developed for the ambulatory monitoring of respiration and electrolyte balance. However, the accuracy of this instrument has not been fully elucidated. The present study compares the performance of the epoc™ analyzer and a conventional bench-top analyzer in operating rooms. Materials and Methods: Fifty blood samples were collected from anesthetized surgical patients and three samples were collected from volunteers into syringes containing lithium heparin. pH, pCO2, pO2, Na+, K+ Ca2+, glucose, lactate and hemoglobin levels were measured using both the epoc™ and calibrated ABL700™ analyzers (Radiometer). Data were statistically analyzed using Pearson correlation coefficients and Bland-Altman plots. Results: Results showed excellent agreement between the values measured using the epoc™ analyzer and those obtained using the ABL700™ analyzer, except for Na+. Conclusions: The epoc™ analyzer is useful in clinical settings, including operating rooms.

Determination of the Effects of Sevoflurane Anesthesia in Different Maturing Stages of the Mouse Hippocampus by Transcriptome Analysis

Purpose: Postoperative cognitive dysfunction (POCD) is a serious complication after general anesthesia. POCD is more likely to occur in elderly patients, but the mechanism of POCD has not been fully elucidated. We hypothesized that the difference of mRNA expression profile in the brain depending on the maturing stage causes the difference in the effect of sevoflurane anesthesia. We investigated the mRNA expression profile of hippocampal cells in young mice and in aged mice under sevoflurane anesthesia using transcriptome analysis. Methods: This study was conducted after approval from our institutional animal ethics committee, the Animal Research Center of Sapporo Medical University School of Medicine (project number: 12-033). Eight mice were assigned to two groups: a young group and an aged group. Each of the 4 mice in the two groups was anesthetized with 3.5% sevoflurane for 1 hour. Subsequently, mRNA was isolated from hippocampal cells and RNA sequencing was performed on an Illumina HiSeq 2500 platform. Mapping of the quality-controlled, filter paired-end reads to mouse genomes and quantification of the expression level of each gene were performed using R software. Results: The Lhx9 gene, which is thought to be associated with neuronal inflammation, was the most highly upregulated gene in aged mice. The Epyc gene, which encodes a protein related to the phospholipase-C pathway and ERK signaling, was the most down-regulated gene in aged mice. Conclusions: The findings suggest that sevoflurane anesthesia induces neuronal inflammation via a LIMhomeodomain family related gene in aged mice and causes POCD.

In reply: Desflurane anesthesia and cognitive function

comparable MMSE scores in the two groups. Sevoflurane is also a suitable anesthetic agent for elderly patients with regard to postoperative MMSE score. However, the results for modified Aldrete score might reflect the better emergence from general anesthesia in the desflurane group. We should present further discussions about the difference between the two anesthetic agents for perioperative cognitive function.