Effect of forced-air warming by an underbody blanket on end-of-surgery hypothermia: a propensity score-matched analysis of 5063 patients

Abstract Background Underbody blankets have recently been launched and are used by anesthesiologists for surgical patients. However, the forced-air warming effect of underbody blankets is still controversial. The aim of this study was to determine the effect of forced-air warming by an underbody blanket on body temperature in anesthetized patients. Methods We retrospectively analyzed 5063 surgical patients. We used propensity score matching to reduce the bias caused by a lack of randomization. After propensity score matching, the change in body temperature from before to after surgery was compared between patients who used underbody blankets (Under group) and those who used other types of warming blankets (Control group). The incidence of hypothermia (i.e., body temperature < 36.0 °C at the end of surgery) was compared between the two groups. A p value < 0.05 was considered to indicate statistical significance. Results We obtained 489 propensity score-matched pairs of patients from the two groups, of whom 33 and 63 had hypothermia in the Under and Control groups, respectively (odds ratio: 0.49, 95% confidence interval: 0.31–0.76, p = 0.0013). Conclusions The present study suggests that the underbody blanket may help reduce the incidence of intraoperative hypothermia and may be more efficient in warming anesthetized patients compared with other types of warming blankets. Trial registration UMIN Clinical Trials Registry (Identifier: UMIN000022909; retrospectively registered on June 27, 2016)

Quantification of muscle tone by using shear wave velocity during an anaesthetic induction: a prospective observational study

Abstract Objectives The quantitative assessment of muscle stiffness or weakness is essential for medical care. Shear wave elastography is non-invasive ultrasound method and provides quantitative information on the elasticity of soft tissue. However, the universal velocity scale for quantification has not been developed. The aim of the study is to determine the shear wave velocities of abdominal muscle during anesthetic induction and to identify methods to cancel the effects of confounders for future development in the quantitative assessment of muscle tone using the universal scale. Methods We enrolled 75 adult patients undergoing elective surgery with ASA-PS I – III in the period between December 2018 and March 2021. We measured and calculated the shear wave velocity (SWV) before and after opioid administration (i.e., the baseline at rest and opioid-induced rigidity condition), and after muscle relaxant administration (i.e., zero reference condition). The SWV value was adjusted for the subcutaneous fat thickness by our proposed corrections. The SWVs after the adjustment were compared among the values in baseline, rigidity, and relaxation using one-way repeated-measures ANOVA and post hoc Tukey–Kramer test. A p-value of < 0.05 was considered to be statistically significant. UMIN Clinical Trials Registry identifier UMIN000034692, registered on October 30, 2018. Results The SWVs in the baseline, opioid-induced rigidity, and muscle relaxation conditions after the adjustment were 2.08 ± 0.48, 2.41 ± 0.60, and 1.79 ± 0.30 m/s, respectively (p < 0.001 at all comparisons). Conclusion The present study suggested that the SWV as reference was 1.79 m/s and that the SWVs at rest and opioid-induced rigidity were ~ 10% and ~ 30% increase from the reference, respectively. The SWV adjusted for the subcutaneous fat thickness may be scale points for the assessment of muscle tone

Nociceptive Sensitization by Activation of Protease-Activated Receptor 2 in a Rat Model of Incisional Pain

Postoperative pain and consequent inflammatory responses after tissue incision adversely affects many surgical patients due to complicated mechanisms. In this study, we examined whether activation of protease-activated receptor 2 (PAR-2), which is stimulated by tryptase from mast cells, elicits nociception and whether the PAR-2 antagonist could reduce incisional nociceptive responses in vivo and in vitro. The effects of a selective PAR-2 antagonist, N3-methylbutyryl-N-6-aminohexanoyl-piperazine (ENMD-1068), pretreatment on pain behaviors were assessed after plantar incision in rats. The effects of a PAR-2 agonist, SLIGRL-NH2, on nociception was assessed after the injection into the hind paw. Furthermore, the responses of C-mechanosensitive nociceptors to the PAR-2 agonist were observed using an in vitro skin–nerve preparation as well. Intraplantar injection of SLIGRL-NH2 elicited spontaneous nociceptive behavior and hyperalgesia. Local administration of ENMD-1068 suppressed guarding behaviors, mechanical and heat hyperalgesia only within the first few hours after incision. SLIGRL-NH2 caused ongoing activity in 47% of C-mechanonociceptors in vitro. This study suggests that PAR-2 may support early nociception after incision by direct or indirect sensitization of C-fibers in rats. Moreover, PAR-2 may play a regulatory role in the early period of postoperative pain together with other co-factors to that contribute to postoperative pain

インタラクティブ進化的計算による室内照明環境デザイン

1 はじめに / 2 システム構成 / 3 GAコーディング / 4 高速化簡易レンダリング / 5 今後の取り組み課題 / 6 まとめ高速な簡易レンダリングを導入することで実用時間の照明設計を可能にしたインタラクティブ進化計算（IEC）を用いた室内照明環境デザイン支援システムを構築する．輝度の異なる多数のLEDを天井や壁全体に分布させた場合，求める照明デザインを探し出すには組合せ数が著しく増加する．この問題解決のために，照明環境デザインにIECを導入する．また室内家具などレンダリングに時間がかかるため，各照明1灯ずつで予めレンダリングした固定視野角からのCG室内照明環境の2次元画像を重み付き加算する簡易法によって実用時間での照明デザインを可能する．Abstract We develop a design support system for room lighting environment using interactive evolutionary computation. When many LED's with different lighting levels are distributed on wide ceiling and walls, the number of optimization solutions for desired lighting environment drastically increases. We introduce IEC into a lighting design support system to overcome this problem. Usually, it take time to render many CG room objects, which hinders lighting design support even IEC is used. We overcome this problem by introducing a fast rendering method that approximates real rendering. First, we make a 2-D room lighting image from a fixed view angle when only one LED is turned on. We made many similar 2-D images by changing the turned LED. The fast rendering method is to generate any lighting image by weighted sum of the 2-D images. By combining the IEC method and the fast rendering method, the lighting design support system can be used by not only professional but also any users practically